A single-phase autophobic hairspray composition containing 0.5% to 10% by weight of a film-forming hairspray resin; 10% to 60% by weight of a binary mixed propellant system; 0.01% to 1.0% by weight of an autophobic silicone hairspray additive; and 10% to 25% by weight water, is described.

The invention relates to an aerosol hairspray composition to achieve styling with improved sensory attributes at high water levels.
Hairspray compositions must meet a number of functional requirements. These include good holding ability and curl retention without giving a harsh, brittle feeling to the hair.
Conventional hairspray formulations are ethanol based and therefore form highly wetting systems for hair. Coalescence of the aerosol droplets on the hair fibre and subsequent ethanol evaporation to leave solid polymer residue leads to a network of fibre-fibre bonds.
There are, however, undesirable consequences in coating hair with polymer, manifesting in perceptions of sensory negatives such as stiffness, rigid feel, stickiness or unnatural feel.
U.S. Pat. No. 4,871,529 describes ethanol solvent-based hairspray compositions which employ a specific type of silicone copolyol which causes the hairspray composition to contract upon drying. This is described as an xe2x80x9cautophobic effectxe2x80x9d which causes large droplets of the composition to form, and produce larger juncture points between fibres. Localisation of deposits in this way is advantageous since it offers stronger bonds and more durable hold, yet reduced sensory negatives such as stiffness and unnatural feel.
U.S. Pat. No. 4,871,529 advises the minimum amount of water in its autophobic systems, if water is present at all. Increasingly, however, with the advent of legislation concerning the volatile organic content of hairsprays, it is desirable to formulate systems with relatively high water content.
U.S. Pat. No. 5,021,238 (Martino et al.) reports the advance of using dimethyl ether (DME) as a hairspray propellant. DME allows use of water as the only solvent thereby significantly reducing the volatiles problem.
However, with this type of propellant it has proved impossible to achieve an autophobic effect at high water levels.
Alternatively, replacement of chlorofluorocarbons with hydrocarbon propellants has been discussed in U.S. Pat. No. 4,859,455 (Nowak, Jr. et al).
However, a problem with hydrocarbon propellants is that it becomes impossible to achieve a single phase system at high water levels. For example, in a water-hydrocarbon system containing more than 15% hydrocarbon, the composition separates into two phasesxe2x80x94an aqueous phase and a hydrocarbon phase.
We have now found that achievement of both an autophobic effect and a single phase system is possible through use of a specific mixture of propellants in combination with a film-forming hairspray resin and an autophobic hairspray additive. Moreover the autophobic effect thus achieved is tolerant to high water levels.
The invention provides a single phase autophobic hairspray composition comprising:
a) from 0.5% to 10% by weight of a film-forming hairspray resin;
b) from 10 to 60% by weight of a propellant including a .mixture of at least one hydrocarbon and a di(C1-C4 alkyl) ether in a weight ratio from 5:1 to 1:10;
c) from 0.01% to 1.0% by weight of an autophobic hairspray additive, being a surfactant or polymer which imparts autophobic behaviour to the hairspray composition, and
d) water.
Film-Forming Hairspray Resin
The hairspray resins employed in compositions of the present invention should be capable of forming a film and holding the hair of the user in place after evaporation of the volatile components of the hairspray composition.
Hairspray resins are well known articles of commerce and many such resinous polymers are available commercially which contain moieties which render the polymers cationic, anionic, amphoteric or nonionic in nature. To provide optimum sprayability, the polymers employed in hairspray compositions typically range in number average molecular weight of from 5,000 to 100,000 with 10,000 to 50,000 being more preferred.
The amount of the resin may range from 0.5 to 10%, preferably 0.75 to 6% by weight of the total composition.
Examples of anionic hairspray resins are:
copolymers of vinyl acetate and crotonic acid;
terpolymers of vinyl acetate, crotonic acid and a vinyl ester of an alpha-branched saturated aliphatic monocarboxylic acid such as vinyl neodecanoate;
copolymers of methyl vinyl ether and maleic anhydride (molar ratio about 1:1) wherein such copolymers are 50% esterified with a saturated alcohol containing from 1 to 4 carbon atoms such as ethanol or butanol;
acrylic copolymers, terpolymers, etc., containing acrylic acid or methacrylic acid as the anionic radical-containing moiety with other monomers such as: esters of acrylic or methacrylic acid with one or more saturated alcohols having from 1 to 22 carbon atoms (such as methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, t-butyl acrylate, t-butyl methacrylate, n-butyl methacrylate, n-hexyl acrylate, n-octyl acrylate, lauryl methacrylate and behenyl acrylate); glycols having from 1 to 6 carbon atoms (such as hydroxypropyl methacrylate and hydroxyethyl acrylate); styrene; vinyl caprolactam; vinyl acetate, acrylamide; alkyl acrylamides and methacrylamides having 1 to 8 carbon atoms in the alkyl group (such as methacrylamide, t-butyl acrylamide and n-octyl acrylamide), and other compatible unsaturated monomers. The polymer may also contain grafted silicone, such as polydimethylsiloxane.
One specific example of a suitable anionic hairspray resin is the emulsion polymerised terpolymer of methacrylic acid, n-butyl acrylate and ethyl acrylate (e.g. in a weight percent ratio of 31:42:27, respectively). Another specific example is Ultrahold(copyright) 8 (CTFA-Cosmetic, Toiletries and Fragrance Association designation of Acrylate/Acrylamide Copolymer).
Other suitable anionic hairspray resins include carboxylated polyurethanes. Carboxylated polyurethane resins are linear, hydroxyl-terminated copolymers having pendant carboxyl groups. They may be ethoxylated and/or propoxylated at least at one terminal end. The carboxyl group can be a carboxylic acid group or an ester group, wherein the alkyl moiety of the ester group contains one to three carbon atoms. The carboxylated polyurethane resin can also be a copolymer of polyvinylpyrrolidone and a polyurethane, having a CTFA designation PVP/polycarbamyl polyglycol ester. Suitable carboxylated polyurethane resins are disclosed in EP 0 619 111 A1 and U.S. Pat. No. 5,000,955. Other suitable hydrophilic polyurethanes are disclosed in U.S. Pat. Nos. 3,822,238; 4,156,066; 4,156,067; 4,255,550; and 4,743,673.
Amphoteric polymers which can contain cationic groups derived from monomers such as t-butyl aminoethyl methacrylate as well as carboxyl groups derived from monomers such as acrylic acid or methacrylic acid can also be used in the present invention. One specific example of an amphoteric hairspray resin is Amphomer(copyright) (octylacrylamide/acrylates/butylaminoethyl methacrylate copolymer) sold by the National Starch and Chemical Corporation.
Examples of nonionic hairspray resins are homopolymers of N-vinylpyrrolidone and copolymers of N-vinylpyrrolidone with compatible nonionic monomers such as vinyl acetate and terpolymers of ethyl acrylate, butyl methacrylate and methyl methacrylate. Nonionic polymers containing N-vinylpyrrolidone in various weight average molecular weights are available commercially from ISP Corporation such as homopolymers of N-vinylpyrrolidone having an average molecular weight of about 630,000 sold by ISP (formerly GAF Corporation) under the tradename PVP K-90 and those having an average molecular weight of about 1,000,000 sold under the trademark of PVP K-120.
Examples of cationic hairspray resins are copolymers of amino-functional acrylate monomers such as lower alkyl aminoalkyl acrylate or methacrylate monomers such as dimethylaminoethyl methacrylate with compatible monomers such as N-vinylpyrrolidone, vinyl caprolactam, or alkyl methacrylates such as methyl methacrylate and ethyl methacrylate and alkyl acrylates such as ethyl acrylate and n-butyl acrylate.
Cationic resins containing N-vinylpyrrolidone are commercially available from ISP Corporation such as those sold under the trademarks of Copolymer 845 and Copolymer 937 (copolymers of N-vinylpyrrolidone and t-butylaminoethyl methacrylate of average molecular weight about 1,000,000) and Gafquat(copyright) 755 and 755N (quaternary ammonium polymers formed by the reaction of dimethyl sulfate and a copolymer of N-vinylpyrrolidone and dimethylaminoethyl methacrylate of average molecular weight about 1,000,000).
With certain of the resins it may be necessary to neutralise some acidic groups to promote solubility/dispersibility.
Examples of suitable neutralising agents include 2-amino-2-methyl-1,3-propanediol (AMPD); 2-amino-2-ethyl-1,3-propanediol (AEPD); 2-amino-2-methyl-1-propanol (AMP); 2-amino-1-butanol (AB); monoethanolamine (MEA); diethanolamine (DEA); triethanolamine (TEA); monoisopropanolamine (MIPA); diisopropanol-amine (DIPA); triisopropanolamine (TIPA); and dimethyl stearamine (DMS). A long chain amine neutralising agent such as lauramidopropyl dimethylamine may be employed, as is described in U.S. Pat. No. 4,874,604. Mixtures of any of the above neutralising agents may be used. Amounts of the neutralising agents will range from about 0.001 to about 10% by weight of the total composition.
Propellant
Essential to the present invention is a mixed propellant system of hydrocarbon and dialkyl ether. The dialkyl ether is a di(C1-C4 alkyl) ether, most preferably dimethyl ether. The hydrocarbon component of the propellant system will be a C3-C5 alkane, especially one selected from propane, isobutane, n-butane and mixtures thereof. An example is a combination of propane and isobutane, such as A50 propellant commercially available from the Aeropress Corporation.
Total amount of propellant will range from 3 to 50%, preferably from 5 to 45%, optimally from 25 to 45% by weight of the total composition.
Weight ratios of total hydrocarbon to dialkyl ether will range from 5:1 to 1:10, preferably from 2:1 to 1:5, more preferably from 1:1 to 1:4, optimally about 1:2 by weight.
Autophobic Hairspray Additive
Also essential to the present invention is an autophobic hairspray additive, being a surfactant or polymer which imparts autophobic behaviour to the hairspray composition.
Autophobic behaviour of the hairspray composition can conveniently be evaluated as follows:
Conventional systems display high wetting of hair fibres. In these systems, solid (including hairspray resin) deposited in fibre-fibre junctions is significantly spread along the fibres from the centre of the junction along the length of the fibres. In contrast, autophobic systems appear to localise deposition at fibre-fibre junctions, with a reduced coating of those fibre regions external to the junctions. This is consistent with the deposit being formed from a poorly wetting system, that is, the liquid makes a high contact angle with the fibre. The high contact angle droplet morphology of the dried autophobic system on crossed hair fibres can be viewed by magnifying lens.
Suitable autophobic hairspray additives may be selected from the group consisting of:
(i) alkyl-pendant silicone copolyols of formula (I):
xe2x80x83where m and n are integers of from 0 to 50, and x and y are integers chosen to give the copolyol a molecular weight of at least 600. Z is hydrogen or a C1-4 alkyl radical;
(ii) dimethicone copolyols of formula (II):
xe2x80x83where n is an integer chosen to give the copolyol a molecular weight of at least 600;
x and xxe2x80x2 are integers of from 1 to 12;
a, axe2x80x2,b, bxe2x80x2 are integers of from 0 to 50, and R is hydrogen or a C1-4 alkyl radical;
(iii) polydimethicone copolyols of formula (III):
xe2x80x83where x and n are integers chosen to give the copolyol a molecular weight of at least 500;
y is an integer of from 1 to 12, and
a and b are integers of from 0 to 50;
(iv) alkyl ethoxylates; and
(v) fluorosurfactants.
Illustrative alkyl-pendant silicone copolyols of formula (I) as referred to above are described in U.S. Pat. No. 4,871,529. A preferred example is the ethoxylated dimethicone copolyol SILWET(copyright) L-7602, ex OSi Specialities.
Dimethicone copolyols of formula (II) referred to above are sometimes designated as xe2x80x9cABAxe2x80x9d type copolymers, due to the presence of alternating polyalkylene oxide and silicone blocks.
Polydimethicone copolyols of formula (III) referred to above are sometimes designated as (AB)n type copolymers.
The molecular weight of the copolyols of formulae (II) and (III) suitably ranges from 500 to 50,000.
Suitable dimethicone copolyols of formula (II) are SILSOFT(copyright) 900, sold by OSi Specialties, having a molecular weight of about 2000, with R being hydrogen and a being 0, and the materials sold by Goldschmidt as TEGOPRENO (copyright) 3012 and 5830 respectively.
Suitable polydimethicone copolyols of formula (III) are those described in U.S. Pat. No. 4,242,466. Illustrative is the material sold by OSi Specialties as SILSOFT(copyright) 487, having a molecular weight of about 150,000, with a and b both greater than 0.
Examples of suitable alkyl ethoxylates are those of general formula (IV):
CnH2n +2 (OCH2CH2)xc3x97OR xe2x80x83xe2x80x83(IV)
where n is an integer of from 5 to 20, preferably from 8 to 18, most preferably 12 to 14;
x is an integer of from 3 to 50, preferably from 3 to 30; and
R is hydrogen or a C1-4 alkyl group, e.g. methyl. Preferably R is hydrogen.
Illustrative are GENAPOL(copyright) C-250, (ex Hoechst Celanese), 1which is coconut fatty alcohol (C8-C18, mainly C12-C14) ethoxylated with 25 moles of ethylene oxide, and DOBANOL(copyright) 91-5 (ex Shell), which is C9-C11 alcohol ethoxylated with 5 moles of ethylene oxide.
Fluorosurfactants are surfactants in which the hydrophobic segment of the molecule contains fluorine. At least one hydrogen atom in the hydrophobic segment contains fluorine. The hydrophobe can be fully fluorinated (perfluorinated) or partially fluorinated. As with conventional surfactants, fluorosurfactants can be classified into four types: anionic, cationic, amphoteric and nonionic. Their structural features are described in the book xe2x80x9cFluorinated Surfactants xe2x80x94Surfactant Science Series Vol. 50xe2x80x9d by Eric Kissa, Marcel Dekker Inc., 1994, Chapter 1.
An example of a suitable fluorosurfactant is the material sold by Dow/3M as L13564, of formula (V):
where Rf is a fluorine containing hydrophobe.
Mixtures of any of the above autophobic hairspray additives may also be used.
Water
Compositions of the present invention include water.
Typical water levels for an ethanol-based aerosol fixing spray are from 2 to 10%, usually about 2 to 6% by weight.
However, with the advent of legislation concerning the flammability and volatile organic content of hairsprays, it is increasingly desirable to formulate systems with relatively high water content. A particular advantage associated with hairsprays according to the present invention is that they can be formulated with high water content, without prejudice to the autophobic effect.
Hairsprays of the present invention can be formulated with a water content of up to 30%, even 45 to 55% , by weight of the total composition. The upper water content limit is not critical to the present invention, but in general is governed by the tendency of the hairspray formulation to impart a sticky feel to the hair if the level of water is too high.
An optimum water level for hairsprays of the present invention is generally from 10 to 25%, e.g. around 15 to 20% by weight of the total composition.
Optional Components
A preferred optional component in hairsprays of the invention is a conditioning agent selected from volatile and non-volatile silicone fluids. Volatile silicone fluids are preferably oils chosen from cyclic or linear polydimethyl siloxanes containing from 3 to 9, preferably from 4 to 5 silicon atoms.
Cyclomethicone is the most preferred cyclic volatile silicone. Linear volatile silicone oils generally have viscosities less than about 5 centistokes at 25xc2x0 C. while cyclic fluids typically have viscosities of less than about 10 centistokes.
Non-volatile silicone oils useful for the present invention include polyalkyl siloxanes, polyalkylaryl siloxanes and polyether siloxane copolymers. Non-volatile polyalkyl siloxanes useful herein include, for example, polydimethyl siloxanes with viscosities of from 5 to 100,000 centistokes at 25xc2x0 C. Among the preferred non-volatile silicones are the polydimethyl siloxanes having viscosities from 10 to 400 centistokes at 25xc2x0 C. These siloxanes are available, for example, from the General Electric Company as SF 1075 methyl phenyl fluid or from Dow Corning as 556 Cosmetic Grade Fluid.
The non-volatile polyalkylaryl siloxane fluids that may be used include, for example, polymethylphenylsiloxanes having viscosities of about 15 to 30,000 centistokes at 25xc2x0 C.
Also includable are minor amounts of other ingredients commonly found in hair care compositions, such as antifoam agents, antioxidants, proteins,preservatives, keratin amino acids, UV inhibitors, fragrances, coloring agents, buffering agents, polyols, and other moisturizing agents. Generally these optional ingredients are included individually at a level of up to about 5% by weight of the total composition.
Preferably, compositions of this invention also contain adjuvants suitable for hair care. Generally such ingredients are included individually at a level of up to 2%, preferably up to 1%, by weight of the total composition.
Among suitable hair care adjuvants, are:
(i) natural hair root nutrients, such as amino acids and sugars. Examples of suitable amino acids include arginine, cysteine, glutamine, glutamic acid, isoleucine, leucine, methionine, serine and valine, and/or precursors and derivatives thereof. The amino acids may be added singly, in mixtures, or in the form of peptides, e.g. di- and tripeptides. The amino acids may also be added in the form of a protein hydrolysate, such as a keratin or collagen hydrolysate. Suitable sugars are glucose, dextrose and fructose. These may be added singly or in the form of, e.g. fruit extracts. A particularly preferred combination of natural hair root nutrients for inclusion in compositions of the invention is isoleucine and glucose. A particularly preferred amino acid nutrient is arginine.
(ii) hair fibre benefit agents. Examples are:
ceramides, for moisturising the fibre and maintaining cuticle integrity. Ceramides are available by extraction from natural sources, or as synthetic ceramides and pseudoceramides. A preferred ceramide is Ceramide II, ex Quest. Mixtures of ceramides may also be suitable, such as Ceramides LS, ex Laboratoires Serobiologiques.

Autophobic hair spray composition comprising film forming resin, propellant, and autophobic hair spray additive

Unilever Home and Personal Care USA, Division of Conopco, Inc.


An electrical device for performing a particular function includes a system circuit for performing the function, and a dedicated power supply for providing power to the circuit. Both the system circuit and the power supply are hermetically sealed within a housing. The device within the housing is intended to be sterilized using high temperature, reaching a sterilization temperature. According to the invention, the device includes a thermal switch which is electrically connected between the system circuit and the power supply. With the present invention, the electrical components of a device are automatically protected from thermal damage during sterilization.

1) Field of the Invention
This invention generally relates to high-temperature sterilization of electronic devices and electromechanical devices and, more particularly, to systems to protect electronic components against the damaging effects of high-temperature sterilization.
2) Discussion of Related Art
Excess thermal energy (i.e., heat) is generally considered undesirable and harmful to electronic circuits. Electronic components of consumer and military electronic devices are each designed to operate within a specific temperature range, depending on the anticipated operational environment and the expected service parameters of the particular component. Generally, the higher the temperature that a particular electronic device or component can withstand without operational failure (or shortened lifespan), the more expensive that component will be to manufacture. Any device which requires many of such high-temperature-rated components, will, of course, end up being expensive as well.
Essentially, all electronic components generate some heat by dissipating energy as they operate. To this end, effective thermal management is important so that the upper end of the operational temperature range may be increased without the component failing. Most semiconductor devices, for example, are not rated for junction temperatures above 175° C., and their performance degrades rapidly with increased temperatures exceeding that upper limit, especially if the applied high temperature is maintained for relatively long periods of time. Interestingly, electronic components that are operating under power are substantially more sensitive to thermal damage than the same components isolated from a power source.
It is common to design thermal management structures and systems into a circuit to help prevent thermal-related failure of the operating components. Most thermal management includes mechanical heat-conduction structure designed to draw heat energy away from the electronic devices, as the heat is generated within or adjacent the component. Such structure includes heat sinks, cooling fans, and liquid-cooling systems, etc.
These cooling systems generally work well at removing excess heat from an operating electronic device because in most cases, there is access to a cooler region into which the excess energy generated by the particular electronic component may easily and naturally migrate, resulting in a cooler operating component. Unfortunately, certain electronic devices are forced to operate in a super-heated environment for a prolonged period of time (between 2 and 120 minutes depending on the sterilization temperature, device size, mass and complexity) where, by the very nature of the environment, no such temperature gradient can effectively exist.
A variety of mechanical and electro-mechanical devices must operate in environments that require the devices to be completely isolated within a protective barrier. In some situations, the "outside environment" (environment located outside the barrier) is hazardous and includes elements or conditions that will adversely affect the operation of the device or shorten its expected useful operative life. In such hazardous environments, the device must be completely sealed and the protective barrier must be made with the particular hazard in mind. For example, implanted devices must be hermetically sealed to prevent the penetration of moisture, which would adversely affect the operation of the device. Also, many medical devices that are to be implanted within a human patient, for example, must also be hermetically sealed, primarily, in this delicate living environment, to prevent infection or contamination caused from within the device.
Certain biologically implanted devices include delicate electronic components typically including integrated circuits, memory chips, and solid state sensors, that are powered by on-board, hermetically-sealed batteries and are all sensitive to high temperatures. Pace-makers, defibrillators, stimulators, drug-delivery devices (such as infusion pumps) are some examples of such powered, implanted devices wherein, for biological-safety reasons, the electronic components and the power supply are both permanently sealed within a metal housing and owing to the sealed arrangement requirements, cannot be mechanically or electrically accessed from outside the housing. The batteries used are built into the device and will provide the necessary power for the operational life of the device.
After manufacture of such devices and prior to them being used (or surgically implanted within a patient), the entire device must be sterilized using either a gas-sterilization system, a gamma radiation system or steam. If a gas is used, typically, Ethylene Oxide (ETO) is applied to the device for a controlled period of time. Sterilizing using ETO may be effective, but many materials tend to absorb the ETO chemical during the process. These components must be properly aerated after the ETO gas has been applied. Furthermore, in such applications wherein the sterilized device contacts humans, new studies have shown that an increasing number of people are sensitive to even the trace amounts of ETO residing on the device after ETO sterilization is complete.
Gamma radiation or E-beam application may be applied to the device to effectively sterilize the entire device, but unfortunately, such radiation applications have been shown to degrade or otherwise damage certain plastic and rubber compounds and, sadly, also electronic components.
Steam sterilization is a simple and effective process and is generally preferred over using ETO or gamma radiation. However, since the system uses heat to kill any microbes on the device, the required temperatures can likely damage onboard electronic components and onboard batteries.
To ensure thorough sterilization, super-heated steam is applied to the hermetically-sealed electronic device for a period generally between 2 and 120 minutes (depending on the sterilization temperature, device size, mass and complexity), during which time the entire device, including any on-board circuitry and batteries will become super-heated. During the sterilization process, all of the components of the device will eventually reach a temperature between 120 and 135 degrees Celsius. Electronic circuits operating in this super-heated environment (while electrically connected to the on-board batteries) for such a prolonged period of time will invariably suffer irreparable thermal damage and will likely fail either immediately, or sometime before its expected operational life has been reached. This potential for failure is incredibly undesirable considering that the device will eventually operate long-term within a human and will likely help the human to live.
Of course, some of the heat-related damage caused by the steam-sterilization process can be mitigated by using high-specification components (e.g., military-spec components). These components undergo critical testing during their manufacture and have been otherwise designed to handle higher temperatures. The problems associated with these military grade components include size, availability, and cost. The military grade components are generally larger and more expensive than their equivalent commercial-grade components. Furthermore, not all components are available in military grade. Considering typical commercial viability of the end product and the limited space available, use of such expensive and larger military-spec components is generally difficult to justify, leaving little option but to rely on cheaper, smaller, yet more-heat sensitive components for many of the devices that must be sterilized.
It is therefore an object of the present invention to provide a thermal-related protection to electronic components, which overcomes the deficiencies of the prior art.

This patent is subject to a terminal disclaimer.

System for protecting circuitry in high-temperature environments


A solid surface sheet includes visible, elongated, shredded cuttings uniformly distributed throughout a matrix wherein the cuttings and the matrix have substantially the same specific weight and wherein a majority of the cuttings are substantially elongated. Related methods are also disclosed including shredding a first mix while in a gel state, curing the cuttings, sorting by size, and using as a filler in a base material to form a blend having a unique appearance and high internal strength. The preferred material is polyester or acrylic. The solid surface sheet can be used as a countertop, floor or wall panel, furniture, and in similar applications.

The present invention concerns a solid composite sheet with visible elongated filler and a method of manufacturing the same.
Various materials including wood, ceramic tiles, and Formica® have been used to make countertops. In recent years, solid surface materials have become highly desirable because of their non-porous and homogeneous nature. To meet the demanding requirements of consumers with varying tastes, different designs and textures have been developed including different fillers used in the process of making solid surface materials. For example, fabricators have used both aluminatrihydrate as a filler and also recycled solid surface particulate materials by grinding them up into granules and reincorporating them into a new solid surface material. Some fabricators have even utilized other materials such as chips and shavings of non-ferrous metals (see Hamami U.S. Pat. No. 6,605,661). However, the heterogeneous nature of this last construction can substantially weaken the solid surface material due to voids that may occur, and due to poor bonding of the polyester base material to non-ferrous filler material. As a result of the poor bonding and different material strengths and due to odd particulate shapes that may trap air, chips and surface defects may be in the top surface of a sheet of this material as it is sanded and buffed to a final high-quality finish. Also, the need for other designs has become increasingly important.
Consequently, a solid surface material having the aforementioned advantages, yet incorporating a different design pattern while maintaining a high internal strength and low tendency for producing surface defects, is desired.

Composite sheet with visible filler and manufacturing method


A process is proposed for cleaning printing machines or printing plates by removing the contaminants from the surfaces to be cleaned by washing them with a microemulsion comprising water, a surfactant, and a water-immiscible organic solvent.

The invention relates to a process for cleaning printing machines and printing plates to remove, in particular, printing inksxe2x80x94for example, oil-based or radiation-curable printing inksxe2x80x94from the cylinders and rollers of printing machines, especially planographic or offset printing machines, and from printing plates, during, for example, an interruption in the printing process.
For said purposes it is common to employ cleaners based on organic solvents and/or aqueous solutions. When machines are at a prolonged standstill in printing plants, or when there is a change of ink, the parts of the printing machine that have come into contact with the printing ink are freed from ink residues. Similarly, when there is an interruption in the printing process, it is necessary to clean printing plates, especially planographic printing plates, carefully in order to remove ink residues and to coat them with preserving solutions based on hydrophilic polymers in order to maintain the hydrophilicity of the nonimage areas. Cleaners containing organic solvents usually have volatile organic components (VOCs) which pollute the atmosphere and are unacceptable from an environmental and workplace health and safety standpoint. Cleaners consisting exclusively or predominantly of apolar organic solvents, furthermore, have the disadvantage that solvent residues which adhere to the parts to be cleaned, such as printing rollers, cannot be washed off with water after cleaning. A clean printing roller, however, is vital for good wetting with printing ink and for effective ink transfer. In the case of some printing plates it is also possible for the ink-carrying print stencil to undergo incipient dissolution by the cleaner and, as a result, to become damaged or even unusable.
DE-B 27 24 557 describes a cleaner for lithographic printing plates which comprises water and water-miscible organic solvents. Its cleaning action with respect to viscous oil-based printing inks is naturally limited.
GB-A 2 089 289 describes oil-in-water and water-in-oil emulsions as cleaners. A disadvantage in this case is the relatively high interfacial tension between the water phase and the oil phase, so that, for example, lipophilic, strongly hydrophobic offset printing inks, owing to their high surface energy, are taken up only slowly and minimally by the continuous water phase cleaner solution.
Similar comments apply to emulsions as described, for example, in WO-A 90/03419 or EP-A 0 498 545.
Furthermore, emulsions of this kind are stable only kinetically but not thermodynamically, so that, especially in the case of temperature fluctuations, they have a tendency to separate [creaming (settling), thickening, flocculation] and so are impaired in their usefulness.
A particularly difficult task is the removal of UV-curable offset or relief inks based on polymerizable monomeric or oligomeric acrylates. They are generally removed using esters or mixtures of esters and mineral oil.
It is an object of the present invention to provide a cleaning process and a liquid cleaner (cleaning composition) which permit the rapid and effective detachment of printing inks without polluting the local environment by vapors from volatile organic components or attacking the print stencil of printing plates.
We have found that this object is achieved by a process for cleaning printing machines or printing plates by removing the contaminants from the surface by washing with a liquid, wherein said liquid is a preferably bicontinuous microemulsion comprising water, a surfactant and, as the oil phase, a water-immiscible organic solvent.
For the purposes of the present specification a microemulsion is a liquid mixture, preferably a bicontinuous mixture, of water phase and oil phase with an extremely low interfacial tension between water phase and oil phase, i.e., an interfacial tension up to three powers of ten lower than that of a conventional water-in-oil or oil-in-water emulsion. In the case of microemulsions this interfacial tension is in the range from 10xe2x88x923 to 10xe2x88x927 N/m, preferably from 10xe2x88x924 to 10xe2x88x926 N/m, and in the case of emulsions customarily in the range from 10xe2x88x923 to 10xe2x88x922 N/m. A microemulsion in the present specification is thermodynamically stable, visually transparent and preferably of low viscosity.
Customary, conventional emulsions may comprise oil phase and water phase in very different proportions by volume. They have a continuous phase and a disperse phase which is present as very small spherules, stabilized by coating with surfactants, in the continuous phase. Depending on the nature of the continuous phase the emulsions are referred to as oil-in-water or water-in-oil emulsions. Ideally these emulsions are kinetically stable, i.e., they persist for prolonged periods although not ad infinitum. In the case of fluctuating temperatures in particular, they may tend toward phase separation by settling, creaming, thickening or flocculating.
Bicontinuous microemulsions comprise two phases, a water phase and an oil phase, in the form of extended, adjacent and interpenetrating domains at the interface between which there is an accumulation of stabilizing surfactants in a monomolecular layer. Bicontinuous microemulsions form very easily, usually spontaneously on account of the very low interfacial tension, when the individual componentsxe2x80x94water, oil and a suitable surfactant systemxe2x80x94are mixed. Since the domains have only very small extents in at least one dimension, in the order of magnitude of nanometers, the microemulsions appear visually transparent and are stable thermodynamically, i.e., for an unlimited time, within a certain temperature range depending on the surfactant system employed.
Bicontinuous microemulsions are described, for example, in the article xe2x80x9cMikroemulsionenxe2x80x94eine wissenschaftliche und anwendungstechnische Fundgrube?xe2x80x9d [Microemulsionsxe2x80x94a scientific and technological treasure chest?] by H.-F. Eicke in Sxc3x96FW-Journal 118 (1992), pages 311 to 314.
In order to achieve the required low interfacial tension at the phase boundaries the microemulsions comprise certain amphiphiles, i.e., surfactants, and also often comprise, in their aqueous phase, dissolved electrolytes and, if desired, further auxiliaries. Electrolytes are added in particular when the amphiphiles are partly or exclusively ionic surfactants.
The use of microemulsions to extract organic pollutants from contaminated soils is described in WO 94/04289. The tertiary extraction of petroleum is another known field of application for microemulsions.
In addition, EP-A-0 498 545 discloses the use of microemulsions as cleaners for surfaces such as those of coated or untreated metal panels, plastics and other surfaces, in particular for the purpose of pretreatment for subsequent coatings.
The invention additionally provides a cleaning composition for conducting the process of the invention, said composition consisting of a microemulsion comprising water, a surfactant and a water-immiscible organic solvent.
The constituents of the microemulsions should be selected such that they do not alter the mechanical properties of components of equipment or sealing materials made of rubber or similar materials, such as their elasticity, flexibility, dimensional stability, etc., as a result of swelling or shrinkage (deswelling).
Water-immiscible organic solvents used are with advantage those having a boiling range above 100xc2x0 C., preferably above 150xc2x0 C. and, in particular, from 200 to 400xc2x0 C. In general, organic solvents having flash points above 100xc2x0 C. are employed. By organic solvents are meant, inter alia, fats and oils, such as colza oil, fatty acid esters, ethers, ketones, aldehydes, and hydrocarbons.
Generally suitable are esters, especially alkyl esters, of relatively long-chain fatty acids. The alkyl group of the alcohol component generally has 1 to 20, preferably 1 to 16 carbon atoms. The fatty acid component normally has 6 to 25, preferably 8 to 18 carbon atoms and can be linear or branched, saturated or unsaturated and contain up to three double bonds in the molecule. The esters generally have an iodine number of from 0 to about 150, preferably from 0 to 40. Compounds with a higher double bond content frequently show a tendency toward resinification and hence toward the deposition of unwanted substances. Such compounds are therefore added only in small amounts if at all. Examples of suitable esters are methyl, ethyl, isopropyl, n-butyl, n-hexyl, 2-ethylhexyl esters and/or isooctyl esters of fatty acids or fatty acid mixtures, examples being those of octanoic, 2-ethylhexanoic, capric, lauric, myristic, palmitic, oleic, linoleic or behenic acids or of soya oil, coconut oil, palm kernel oil, palm oil, sunflower oil, sperm oil, tall oil, rapeseed oil, castor oil or tallow fatty acids. Examples of specific typical esters are coconut fatty acid 2-ethylhexyl ester, tall oil fatty acid n-hexyl ester, rapeseed oil methyl ester, methyl oleate, methyl stearate, isopropyl palmitate, ethyl laurate, 2-ethylhexyl 2-ethylhexanoate, and n-octyl octanoate. In addition to these esters, ethers with a high boiling range, such as dioctyl ethers, and also triglycerides, such as rapeseed oil, coconut oil or soya oil, are also suitable.
A feature of the esters is their very low vapor pressure, so that no atmospheric pollution is caused when they are used. As is generally the case with bicontinuous microemulsions, the proportions of aqueous and organic phase by volume are approximately within the same order of magnitude; i.e., the volume ratio of water to organic phase is generally from 10:90 to 90:10, preferably from 25:75 to 75:25 and, in particular, from 40:60 to 60:40.
As surfactants it is possible in principle to employ those which differ in their amphiphilic nature, viz. anionic, cationic, amphoteric and nonionic surfactants or mixtures thereof.
Suitable anionic surfactants are C10 to C20, preferably C12 to C16 alkyl sulfates, for example, sodium dodecyl sulfate; C10 to C20, preferably C12 to C16 alkyl polyether sulfates, for example, sodium dodecyloxypolyethoxysulfate; alkali metal salts of diisooctylsulfosuccinic acid; alkali metal salts of alkylbenzenesulfonic acids, for example, sodium dodecylbenzenesulfonate, of dialkyl phosphates, and of carboxylates, for example, of fatty alkyl ether carboxylates. Some anionic surfactants, an example being sodium dodecyl sulfate, are often used together with alkanols such as butanol, pentanol or hexanol as cosurfactants and/or with alkali metal salts or alkaline earth metal salts, for example, sodium chloride or sodium sulfate or calcium chloride, or with other electrolytes, for example NaOH, KOH, phosphates or silicates. In addition, the microemulsions employed in accordance with the invention may also include complexing agents such as ethylenediaminetetraacetic acid, nitrilotriacetic acid or methylglycinediacetic acid, corrosion inhibitors and/or preservatives.
The alkanols can be added in amounts of up to 20% by weight, preferably up to 10% by weight, and the electrolytes in amounts up to 10% by weight, preferably up to 5% by weight. Cationic surfactants which can be used to prepare microemulsions are, for example, alkyltrimethylammonium halides having alkyl chain lengths of about 8 to 18 carbon atoms and/or quaternized imidazolinium salts or pyridinium salts.
Suitable nonionic or nonionogenic surfactants are polyglycol monoalkyl ethers with alkyl chain lengths from C8 to C18, preferably C10 to C16, and from 2 to 20, preferably from 3 to 15 oxyalkylene, especially oxyethylene, oxypropylene and/or oxybutylene, units, or block copolymers comprising these units. It is common to use C10 to C15 alkyl ethers of polyglycols having 3 to 10 oxyalkylene units. In the majority of cases these are technical-grade products having a more or less broad molecular weight distribution. Surfactants having a narrow molecular weight distribution, prepared over special catalysts, can also be employed. Also suitable are triglyceride alkoxylates, examples being reaction products of 1 mol of triglyceride with from 1 to 50 mol of alkylene oxide, especially from 10 to 50 mol of ethylene oxide. It is also possible to use saccharide-based surfactants, examples being alkylpolyglucosides and glucosamides.
The microemulsions employed in accordance with the invention contain preferably anionic surfactants, usually in combination with one or more nonionic surfactants. However, it is also possible to prepare microemulsions with nonionic surfactants alone.
Achieving an optimum cleaning effect in each individual case, for each combination of organic solvent, surfactant or surfactants and, if appropriate, electrolytes and complexing agents in aqueous solution requires defined, relatively narrow ranges of proportions of the individual components, which can be determined by simple routine experiments. In general, the proportion of surfactants in the microemulsion overall is in the range from 1 to 35, preferably from 1 to 25 and, in particular, from 7 to 25% by weight. Too high a proportion of surfactant may cause cleaning problems, or the drying of the printing rollers may present difficulties.
Proportions employed are generally from 1 to 20, preferably from 3 to 15 and, in particular, from 5 to 10% by weight of anionic surfactant; from 1 to 20% by weight of polyethylene glycol monoalkyl ether; from 0.1 to 10, preferably from 0.5 to 5% by weight of reaction product of triglyceride with ethylene oxide; and from 1 to 20% by weight of polyalkylene glycol monoalkyl ether with oxyethylene and/or oxypropylene units.
The microemulsions employed in accordance with the invention generally contain from 5 to 60, preferably from 20 to 60% by weight of water-immiscible organic solvent and from 20 to 80, preferably from 30 to 60% by weight of water. All percentages by weight here are based on the overall weight of the finished microemulsion.
Every microemulsion is thermodynamically stable within a defined temperature range. Preference is given to those microemulsions which are thermodynamically stable at room temperature and below. In many cases, however, it is also possible successfully to employ those microemulsions whose stability range lies above room temperature, for example, between 50 and 60xc2x0 C.
High concentrations of surfactants in known cleaning liquids often lead to poor printing ink detachment in association with surfactant deposits on the printing rollers; these disadvantages do not occur with the microemulsions employed in accordance with the invention.
When the cleaning process of the invention is performed the microemulsion is applied to those parts of the printing machine that are to be cleaned. The surface of the printing ink is wetted quickly, uniformly and completely, so that the printing ink is rapidly taken up by the cleaning liquid and dissolved or emulsified, respectively. The residues of microemulsion can easily be removed by washing with water. The same applies to the residues of ink which remain on a printing plate which is to be cleaned and preserved following an interruption in printing, especially an offset or relief printing plate. The important factor here is primarily the complete removal of ink residues from the nonimage or background areas of the printing plate, on which the required hydrophilicity must be maintained, for example, in planographic or offset printing when the printing operation is resumed. Reference to a printing plate in the context of this description is to a ready-to-print plate as generally obtained by exposure and development of a photosensitive printing plate.
The microemulsions employed in accordance with the invention are also suitable for cleaning other substances, such as plastics, old coatings, primers and untreated metal panels. They can be employed, for instance, as cleaners in the automotive refinish sector, and as brush cleaners.

Method for cleaning printing machines and printing moulds


A shape memory alloy (SMA) actuator for engaging and actuating a device. The actuator includes an engagement mechanism, a bias element, and a SMA object(s). The SMA actuator may automatically and passively transfer to a backup or redundant feature that resets or extends the actuator's operational life. In one embodiment, the SMA actuator includes an additional SMA object(s) that replaces the primary SMA object(s) in the event the primary SMA object(s) breaks. The SMA actuator may also be configured to apply a dynamic stress to the SMA object during transition of the object to modify the transition temperatures of the object. The SMA actuator may be part of a fluid distribution system, such as a heating, ventilation, and air conditioning (HVAC) system and used to control the flow of fluid, such as air, from the distribution system.

Shape memory alloys (SMAs) are metallic alloys that may recover apparent permanent strains when they are heated above a certain temperature. SMAs have two stable states or phases; a hot or austenite state and a cold or martensite state. The temperatures at which the SMA changes states (i.e. its crystallographic structure) are a characteristic of the particular alloy. Selecting the material composition of the alloy and anneal temperatures of the alloy may be used to control the alloy's transition temperatures.
In the austenite state, the alloy is hard and rigid, while in the martensite state, the alloy is softer and flexible. In the martensite state, the SMA may be stretched or deformed by an external force. Upon heating, the SMA will return to its austenite state and contract or recover any reasonable stretch that was imposed on it. Thus, the SMA recovers with more force that was required to stretch it out. This exerted force upon contraction may be used to perform any number of tasks such as, but not limited to, turning a device on or off, opening or closing an object, or actuating a device or object.
HVAC systems provide air or another fluid to compartments, such as rooms for example. A diffuser may be provided at the system outlet to distribute, in a particular way, the air or other fluid entering the room. For example, the diffuser may have one or more blades to direct the flow of the air.
Due to the buoyancy effect of air (i.e. cold air will naturally sink and hot air will naturally rise), heating air and cooling air are preferably provided to a room in different patterns. When both heating and cooling air are provided to the room through a single diffuser, the ability to adjust the diffuser to provide different flow patterns is desirable. Some diffusers may be manually adjusted while other diffusers may sense supply air temperature and adjust the diffuser through the use of a powered control system, bimetallic strips, or wax motors.


The present invention relates to absorbent articles such as sanitary napkins and pantiliners and the use of backsheet constructions comprising a three dimensional formed film therein, to provide masking of the materials stored in the absorbent article when viewed through the garment facing surface of the absorbent article.

The present invention relates to absorbent articles such as sanitary napkins and pantiliners. In particular the present invention relates to the use of backsheet constructions within absorbent articles to provide masking of the materials stored within the article when viewed through the garment facing surface of the article.
Absorbent articles such as sanitary napkins, diapers, incontinence products and perspiration pads are well known in the art. Typically these articles comprise a wearer facing surface and a garment facing surface. The wearer facing surface receives discharges from the body such as urine, faeces, vaginal discharges and the like which are to be absorbed and stored by the article. In order for the article to absorb the discharges the wearer facing surface of the articles needs to be liquid permeable. This wearer facing surface is known as the topsheet.
Topsheets are also well known in the art and are typically selected nonwovens, wovens or apertured film materials. Wovens and nonwovens are desirable in so far as they provide a clothlike appearance to the topsheet and appear relatively soft and comfortable to the wearer. However, the problem with such topsheets is that they also have some capacity to absorb. The topsheet thus rapidly becomes saturated and feels wet to the wearer of the product. Furthermore, such woven or nonwoven topsheets also rapidly develop a used, unclean and unsanitary appearance. Furthermore, the absorbed fluids are readily visible through the topsheet which is also considered unsightly and undesirable by consumers.
Attempts at remedying these problems have principally resided in providing the topsheet with surface treatments such as surfactants or fillers. However, neither of these treatments have resolved the problem satisfactorily. Alternatively it has also been proposed to provide alternative topsheet materials such as apertured formed films which have funnelled apertures which are designed to promote the passage of liquid discharge through the topsheet and into the absorbent core. These types of topsheet are preferred in that the problem of rewet is usually avoided. However, again these materials whilst reducing the visibility of the absorbed liquid contained in the absorbent core below do not entirely eliminate the problem.
In addition the problem of masking of the absorbed fluids and materials is not however merely limited to the stains from materials and fluids contained in the core which are visible when the product is viewed from or through the topsheet or the wearer facing surface of the article. Infact, this problem is also equally prevalent when the product is viewed from or through the backsheet or the garment facing surface where the absorbent fluids are also readily visible. Typically, these stains of the absorbed fluid in the absorbent core are particularly noticeable to the consumer of for example sanitary napkins or pantyliners as the article is removed from the undergarment and is folded for disposal. Again, it considered particularly undesirable to the consumers to view these stains as it appears that the absorbed material is in close contact to the undergarment and thus is unsanitary and that leakage may have occurred even if the absorbent capacity of the product has not been fully utilised.
A solution that has been proposed to address this problem and prevent the easy observation of stains through the backsheet material is simply to provide the backsheet or absorbent core with a coloured or non white appearance. However, coloured absorbent articles are unacceptable to consumers from an aesthetic standpoint, in particular because in contrast to white products coloured products are considered by many consumers to have a used and unsanitary appearance and are therefore undesirable.
Hence there still exists a need to provide masking of the absorbed materials contained within the absorbent core when viewed through the rear side or garment facing surface of the article without the necessity of utilising coloured article components.
It has now been surprisingly found that this problem may be addressed by the incorporation and use of a backsheet layer within an absorbent article wherein the backsheet comprises a three dimensional formed film layer.
The present invention relates to the use of a backsheet comprising a three dimensional formed film layer absorbent article, preferably a breathable absorbent article. Said article comprises a wearer facing surface and a garment facing surface and said backsheet comprises said garment facing surface. Accordingly, the present invention relates in particular to the use of said formed film layer to provide stain masking through said garment facing surface of said absorbent article.
The present invention relates to absorbent disposable articles such as sanitary napkins, panty liners, incontinence products, perspiration pads and baby diapers. According to the present invention these products comprise a wearer facing surface, and a garment facing surface. Typically, such products comprise a liquid pervious topsheet providing the wearer facing surface, a backsheet providing the garment facing surface and an absorbent core intermediate said topsheet and said backsheet. The present invention relates to such articles which preferably comprise a moisture vapour permeable, liquid impervious backsheet more commonly referred to as a breathable backsheet.
The absorbent articles can also comprise any of the components or features usual in the art, in particular side wrapping elements, side flap components, or wings as well as any sort of extensibility or elastication feature can be comprised in absorbent articles. For example a typical sanitary napkin or panty liner comprises an adhesive area on the garment facing surface of the backsheet providing the panty-fastening adhesive which is covered by a release paper, wrapper or the like prior to the use of the article.
The absorbent article for absorbing liquid is described below by reference to a sanitary napkin or panty liner. However products such as adult or baby diapers, incontinence products or perspiration pads can similarly benefit from the present invention.
Backsheet
The absorbent article according to the present invention comprises as an essential feature a backsheet. The backsheet primarily prevents the extrudes absorbed and contained in the absorbent structure from wetting articles that contact the absorbent product such as underpants, pants, pyjamas and undergarments thereby acting as a barrier to fluid transport. The backsheet typically extends across the whole of the absorbent structure and can extend into and form part of, or all of the sideflaps, side wrapping elements or wings. In addition to acting as a liquid barrier, the backsheet of the present invention is also preferably breathable such that it permits the transfer of at least moisture vapour, preferably both vapour and air through it and thus allows the circulation of gases into and out of the backsheet.
It has now been further surprisingly identified that the utilisation of a backsheet comprising a three dimensional formed film layer also delivers desirable benefits in terms of masking of the material contained within the absorbent article. In particular, the use of a backsheet comprising a three dimensional formed film layer provides a reduction in the stain visible when the article is viewed from the garment facing surface.
The amount of absorbed fluid and material within the core that can be observed through the backing can be readily quantified by utilising the following as described herein. This test method utilises reflection spectrophotometric analysis to asses the basking ability of the backsheet construction in terms of whiteness and redness. Preferably the whiteness (L) parameter is greater than 70, more preferably greater than 75 and most preferably greater than 80 and the redness (a) parameter is preferably less than 5, more preferably less than 4, and most preferably less than 3.
According to the present invention suitable three dimensional formed films for use as backsheets to provide the benefits as described herein above may be any three dimensional formed film known in the art. The formed films may be apertured or non apertured. However, apertured formed film layers are particularly preferred due to their ability to provide breathability to the absorbent article.
Whilst not being bound by theory it is believed that the stain masking through the garment facing surface of the absorbent article provided by three dimensional films is achieved by a result of two principle effects. Firstly the typically utilised 2 dimensional films have a width of approximately only 20 to 30 micrometers and are thereby effectively transparent and allow the materials contained in the core to be readily observed In contrast the use of a 3-dimensional film within the backsheet construction creates by its very nature of protruding funnels an increased width between the core and the garment facing surface of the article of approximately 500 micrometers, at which the ability of the human eye to detect the materials contained in the core is considerably reduced. Secondly, the incorporation of 2-dimensional films within the backsheet construction also results in the some of the absorbed material in the core being smeared over the surface of the backsheet material with which the core comes in contact with. This again further accentuates the visibility of the absorbed materials through the backsheet. However, in contrast the use of 3-dimensional films of the present invention reduces the surface area contact between the core and the backsheet and as a result the absorbed material is not smeared across the surface of the backsheet. As a result of the combination of these effect the visibility of the absorbent materials through the garment facing surface of the absorbent articles is reduced.
Suitable apertured formed films for use herein include films which have discrete apertures which extend beyond the horizontal plane of the garment facing surface of the layer towards the core thereby forming protuberances. The protuberances have an orifice located at its terminating end. Preferably said protuberances are of a funnel shape, similar to those described in U.S. Pat. No. 3,929,135. The apertures located within the plane and the orifices located at the terminating end of protuberance themselves maybe circular or non circular provided the cross sectional dimension or area of the orifice at the termination of the protuberance is smaller than the cross sectional dimension or area of the aperture located within the garment facing surface of the layer. Preferably said apertured performed films are uni directional such that they have at least substantially, if not complete one directional fluid transport towards the core.
Other suitable formed film layers for use herein include macroscopically expanded films as described in for example in U.S. Pat. Nos. 4,637,819 and 4,591,523.
According to the present invention the backsheet may in addition to said three dimensional formed film layer comprising additional layers. Any layer known in the art as a suitable backsheet material may be effectively employed and includes wovens or nonwoven material, polymeric films such as thermoplastic films of polyethylene or polypropylene, or composite materials such as a film-coated nonwoven material. Preferably, the backsheet is a polyethylene film having a thickness of from about 0.012 mm (0.5 mil) to about 0.051 mm (2.0 mils).
Exemplary polyethylene films are manufactured by Clopay Corporation of Cincinnati, Ohio, under the designation P18-0401 and by Ethyl Corporation, Visqueen Division, of Terre Haute, Ind., under the designation XP-39385. The backsheet is preferably embossed and/or matte finished to provide a more clothlike appearance.
In a preferred embodiment of the present invention the additional layers are also moisture vapour permeable and hence breathable. Suitable moisture vapour permeable layers include 2 dimensional, planar micro and macro-porous films, macroscopically expanded films, formed apertured films and monolithic films. According to the present invention the apertures in said layer may be of any configuration, but are preferably spherical or oblong and may also be of varying dimensions. The apertures preferably are evenly distributed across the entire surface of the layer, however layers having only certain regions of the surface having apertures are also envisioned.
Suitable 2 dimensional porous planar layers of the backsheet may be made of any material known in the art, but are preferably manufactured from commonly available polymeric materials. Suitable materials are for example Goretex(trademark) or Sympatex(trademark) type materials well known in the art for their application in so-called breathable clothing. Other suitable materials include XMP-1001 of Minnesota Mining and Manufacturing Company, St. Paul, Minn., USA and Exxaire XBF-101W, supplied by the Exxon Chemical Company. As used herein the term 2 dimensional planar layer refers to layers having a depth of less than 1 mm, preferably less than 0.5 mm, wherein the apertures have an average uniform diameter along their length and which do not protrude out of the plane of the layer. The apertured materials for use as a backsheet in the present invention may be produced using any of the methods known in the art such as described in EPO 293 482 and the references therein. In addition the dimensions of the apertures produced by this method may be increased by applying a force across the plane of the backsheet layer (i.e. stretching the layer).
Suitable monolithic films include Hytrel(trademark), available from DuPont Corporation, USA, and other such materials as described in Index 93 Congress, Session 7A xe2x80x9cAdding value to Nonwovensxe2x80x9d, J-C. Cardinal and Y. Trouilhet, DuPont de Nemours international S.A, Switzerland such as Pebax(trademark), available from Elf Atochem (France) and Estane(trademark) available from BF Goodrich (Belgium).
Preferred breathable backsheets for use herein are those having a high moisture vapour exchange, most preferably both a high moisture vapour and high air exchange. Particularly preferred backsheets for the present invention comprise at least two layers comprising said three dimensional apertured formed film and at least one additional layer selected from the above, such as a microporous layer or an apertured formed film a fibrous woven or nonwoven. The most preferred breathable backsheet component comprises a microporous film and an apertured formed film.
The Topsheet
According to the present invention the absorbent articles comprise a topsheet. The topsheet is compliant, soft feeling, and non-irritating to the wearer""s skin. The topsheet also can have elastic characteristics allowing it to be stretched in one or two directions in portions of the topsheet or throughout its extension. Further, the topsheet is fluid pervious permitting fluids (e.g., menses and/or urine) to readily penetrate through its thickness. A suitable topsheet can be manufactured from a wide range of materials such as woven and nonwoven materials; polymeric materials such as apertured formed thermoplastic films, apertured plastic films,, and hydroformed thermoplastic films; and thermoplastic scrims. Suitable woven and non woven materials can be comprised of natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polymeric fibers such as polyester, polypropylene, or polyethylene fibers) or from a combination of natural and synthetic fibers or bi-/multi-component fibers and are preferably hydrophobic.
Preferred topsheets for use in the present invention are selected from high loft nonwoven topsheets and apertured formed film topsheets. Apertured formed films are especially preferred for the topsheets because they are pervious to body exudates and yet non absorbent and have a reduced tendency to allow fluids to pass back through and rewet the wearer""s skin. Thus, the surface of the formed film that is in contact with the body remains dry, thereby reducing body soiling and creating a more comfortable feel for the wearer. Suitable formed films are described in U.S. Pat. Nos. 3,929,135; 4,324,246; 4,342,314; 4,463,045; and 5,006,394. Particularly preferred micro apertured formed film topsheets are disclosed in U.S. Pat. Nos. 4,609,518 and 4,629,643. A preferred topsheet for the present invention comprises the formed film described in one or more of the above patents and marketed on sanitary napkins by The Procter and Gamble Company of Cincinnati, Ohio as xe2x80x9cDRI-WEAVExe2x80x9d.
Topsheets having not a homogeneous distribution of liquid passage ways but only a portion of the topsheet comprising liquid passage ways are also contemplated by the present invention. Typically such topsheets would have the liquid passage ways oriented such that they result in a centrally permeable and peripherally impermeable topsheet for liquids.
The wearer facing surface of the formed film topsheet can be hydrophilic so as to help liquid to transfer though the topsheet faster than if the body surface was not hydrophilic. In a preferred embodiment, surfactant is incorporated into the polymeric materials of the formed film topsheet such as is described in PCT-publication WO 93/09741. Alternatively, the body surface of the topsheet can be made hydrophilic by treating it with a surfactant such as is described in U.S. Pat. No. 4,950,254.
Another alternative are so called hybrid topsheets which incorporate fibrous and film like structures. Particularly useful embodiments of such hybrid topsheets are disclosed in PCT publications WO 93/09744; WO 93/11725 or WO 93/11726.
When referring to the topsheet a multi layer structure or a mono layer structure is contemplated. The hybrid topsheet mentioned above is such a multi layer design but other multi layer topsheets such as primary and secondary topsheet designs are also considered.
The topsheet typically extends across the whole of the absorbent structure and outside the area coextensive with the absorbent structure. The topsheet can extend and form part or all of the preferred side flaps, side wrapping elements or wings.
Absorbent Core
According to the present invention the absorbent cores suitable for use in herein may be selected from any of the absorbent cores or core system known in the art. As used herein the term absorbent core refers to any material or multiple material layers whose primary function is to absorb, store and distribute fluid.
According to the present invention, the absorbent core can include the following components: (a) an optional primary fluid distribution layer preferably together with a secondary optional fluid distribution layer; (b) a fluid storage layer; (c) an optional fibrous (xe2x80x9cdustingxe2x80x9d) layer underlying the storage layer; and (d) other optional components.
a Primary/Secondary Fluid Distribution Layer
One optional component of the absorbent core according to the present invention is a primary fluid distribution layer and a secondary fluid distribution layer. The primary distribution layer typically underlies the topsheet and is in fluid communication therewith. The topsheet transfers the acquired fluid to this primary distribution layer for ultimate distribution to the storage layer. This transfer of fluid through the primary distribution layer occurs not only in the thickness, but also along the length and width directions of the absorbent product. The also optional but preferred secondary distribution layer typically underlies the primary distribution layer and is in fluid communication therewith. The purpose of this secondary distribution layer is to readily acquire fluid from the primary distribution layer and transfer it rapidly to the underlying storage layer. This helps the fluid capacity of the underlying storage layer to be fully utilized. The fluid distribution layers can be comprised of any material typical for such distribution layers.
b Fluid Storage Layer
Positioned in fluid communication with, and typically underlying the primary or secondary distribution layers, is a fluid storage layer. The fluid storage layer can comprise any usual absorbent material or combinations thereof. It preferably comprises absorbent gelling materials usually referred to as xe2x80x9chydrogelxe2x80x9d, xe2x80x9csuperabsorbentxe2x80x9d, hydrocolloidxe2x80x9d materials in combination with suitable carriers.
The absorbent gelling materials are capable of absorbing large quantities of aqueous body fluids, and are further capable of retaining such absorbed fluids under moderate pressures. The absorbent gelling materials can be dispersed homogeneously or non-homogeneously in a suitable carrier. The suitable carriers, provided they are absorbent as such, can also be used alone.
Suitable absorbent gelling materials for use herein will most often comprise a substantially water-insoluble, slightly cross-linked, partially neutralised, polymeric gelling material. This material forms a hydrogel upon contact with water. Such polymer materials can be prepared from polymerizable, unsaturated, acid-containing monomers which are well known in the art.
Suitable carriers include materials which are conventionally utilised in absorbent structures such as natural, modified or synthetic fibers, particularly modified or non-modified cellulose fibers, in the form of fluff and/or tissues. Suitable carriers can be used together with the absorbent gelling material, however, they can also be used alone or in combinations. Most preferred are tissue or tissue laminates in the context of sanitary napkins and panty liners.
An embodiment of the absorbent structure made according to the present invention comprises a double layer tissue laminate formed by folding the tissue onto itself. These layers can be joined to each other for example by adhesive or by mechanical interlocking or by hydrogen bridge bands. Absorbent gelling material or other optional material can be comprised between the layers.
Modified cellulose fibers such as the stiffened cellulose fibers can also be used. Synthetic fibers can also be used and include those made of cellulose acetate, polyvinyl fluoride, polyvinylidene chloride, acrylics (such as Orlon), polyvinyl acetate, non-soluble polyvinyl alcohol, polyethylene, polypropylene, polyamides (such as nylon), polyesters, bicomponent fibers, tricomponent fibers, mixtures thereof and the like. Preferably, the fiber surfaces are hydrophilic or are treated to be hydrophilic. The storage layer can also include filler materials, such as Perlite, diatomaceous earth, Vermiculite, etc., to improve liquid retention.
If the absorbent gelling material is dispersed non-homogeneously in a carrier, the storage layer can nevertheless be locally homogenous, i.e. have a distribution gradient in one or several directions within the dimensions of the storage layer. Non-homogeneous distribution can also refer to laminates of carriers enclosing absorbent gelling materials partially or fully.
c Optional Fibrous (xe2x80x9cDustingxe2x80x9d) Layer
An optional component for inclusion in the absorbent core according to the present invention is a fibrous layer adjacent to, and typically underlying the storage layer. This underlying fibrous layer is typically referred to as a xe2x80x9cdustingxe2x80x9d layer since it provides a substrate on which to deposit absorbent gelling material in the storage layer during manufacture of the absorbent core. Indeed, in those instances where the absorbent gelling material is in the form of macro structures such as fibers, sheets or strips, this fibrous xe2x80x9cdustingxe2x80x9d layer need not be included. However, this xe2x80x9cdustingxe2x80x9d layer provides some additional fluid-handling capabilities such as rapid wicking of fluid along the length of the pad.
d Other Optional Components of the Absorbent Structure
The absorbent core according to the present invention can include other optional components normally present in absorbent webs. For example, a reinforcing scrim can be positioned within the respective layers, or between the respective layers, of the absorbent core. Such reinforcing scrims should be of such configuration as to not form interfacial barriers to fluid transfer. Given the structural integrity that usually occurs as a result of thermal bonding, reinforcing scrims are usually not required for thermally bonded absorbent structures.
Another component which can be included in the absorbent core according to the invention and preferably is provided close to or as part off the primary or secondary fluid distribution layer are odor control agents.
A preferred sanitary napkin or panty liner made according to the present invention has a pair of side wrapping elements or xe2x80x9cundergarment covering componentsxe2x80x9d. These elements or components provide coverage of the wearer""s panties to reduce side soiling (i.e., staining of the edges of the panty crotch) and are typically smaller than conventional flaps or wings.
The function of the side wrapping elements, whether integral with the article or joined to the article after being formed separately, is further improved by rendering them extensible in one or both directions parallel to the longitudinal axis and/or lateral axis. The extensibility can be provided across all or only part of the side wrapping elements and can be achieved by pleating or ring-rolling those parts which are to be rendered extensible.
According to the present invention the topsheet, backsheet and absorbent core components are joined together to provide the absorbent article. Typically, at least two, preferably all of the components of the article are joined to form the article. Each of said components of the absorbent article comprise at least one layer and have a wearer facing surface and a garment facing surface. Typically, adjacent garment facing surfaces form a common interface with the wearer facing surface of an adjacent component or layer. The elements or layers are joined together across this common interface. In this manner, the topsheet is joined to the absorbent core, and the core is joined to the backsheet. In addition, the topsheet may be directly or indirectly by joined to the backsheet at the periphery of the absorbent article. Furthermore, particularly in sanitary napkin, panty liner and incontinence product applications, the garment facing surface of the backsheet also provides the surface to which the absorbent article is releasably joined to the garment of the user of the product. Prior to use, this surface is typically provided with a protective cover. Any means known in the art to join the components of the absorbent article and provide the garment fastening. May be utilised such as utilising a continuous layer of adhesive, a patterned layer of adhesive, such as spirals, or spots, or using heat bonds, pressure bonds, mechanical bonds and the like.
Test Method
Backsheet Masking Test-Reflection Spectrophotometric Analysis
This test assesses the backsheet masking level (redness/whiteness) of a sanitary napkin following usage or by simulated loading of the pad with synthetic blood.
Apparatus
X-Rite colorimetric Mod: 948/968. This equipment measures spectral reflectance according to the Hunter Lab (L, a, b components) according to industry standard CIE1976.
Procedure: Laboratory Simulation of Masking:
1. In accordance with the manual procedure calibrate the calorimetric X-Rite.
2. Place a fresh pad on the laboratory bench with the wearer facing surface (topsheet) facing upwards.
3. Load 10 ml of synthetic blood onto the centre pad.
4. After 1 min. apply a pressure/weight of 60 g/sqcm on the pad.
5. Remove the weight and place the pad with garment facing surface (backsheet) facing upwards and remove the silicon paper.
6. Place the X-rite instrument on the backsheet and measure the Hunter L,a,b values. Take an average of 10 readings over the loaded area.
7. The test is repeated on 5 separate pads.

Use of stain masking backsheets in absorbent articles