NO802143L - PREPARATION AND PROCEDURE FOR COMBUSTING DUST ALLERGENS - Google Patents

Description

Dust in private homes or "house dust" is the cause of a number of troublesome allergy symptoms in an unknown number of people who will be more or less constantly bothered by sneezing and a runny nose or by hoarseness and shortness of breath. The possible harmful effects of house dust have long been known. In recent times, the house-dust fauna, especially arthropods such as various types of mites and their waste, have been the subject of investigation in relation to house-dust atopy, an important factor in the etiology of bronchial asthma and rhinitis. The symptoms resulting from an allergy to house dust are usually those found in perennial allergic rhinitis, sneezing, runny nose and nasal congestion, as well as watery and sore eyes. These symptoms can be identical to those found in connection with seasonal hay fever.

In the literature to date, no recommendations can be found with regard to the control of house dust mites. Neither chemical nor health control agents seem possible due to a lack of knowledge in the field.

Furthermore, it has been shown that most mite control agents have little effect at concentrations below one percent, which in most cases is too strong a treatment for them to be used inside houses where. one has a high mite density, such as mattresses, upholstered furniture etc., where people travel daily. Furthermore, these treatments have not combated or controlled the mites' waste, which is also known as an allergen source.

It is therefore a purpose of the present invention to combat allergens found in house dust. V

Furthermore, it is a purpose of the invention to provide a preparation or a composition for combating the allergens found in substances, and where this composition can be used in environments where people travel.

Furthermore, it is a purpose of the invention to combat waste from mites found in substances.

Furthermore, it is a purpose of the invention to be able to treat substances in such a way as to limit the mobility of the mites and the mite waste, maintain an environment with low humidity around the mites and isolate them from critical nutrients.....

Furthermore, it is a purpose of the invention to be able to apply a preparation to combat allergens found in substances by means of a device which enables regulation of the application speed and that said preparation is evenly applied, so that the substance can be completely coated, but at the same time will become dry within a reasonable period of time.

These other purposes of the invention will be apparent from the following description.

The connection between different types of mites, allergies and house dust seems to suggest that relief from allergies can be achieved in a typical household environment by changing the mites' • microenvironment in the specific areas where one. combating the mites' activity will have the greatest effect. Furthermore, such a change to the mites' microenvironment can be achieved in such a way that this is compatible with possible exposure to humans.

It is well known that these areas in a typical home are characterized by the dominance of substances, such as upholstered furniture, mattresses, bed mats and wallpapers, and these will provide ideal host micro-environments for different types of mites. It has also been found that the latter substances are periodically treated with a composition that has certain physical and chemical properties, so the mites' activity on and in these substances can be regulated with a corresponding reduction in these substances' allergy potential. It has also been found that the shape of the preparation is important for combating said mites, and more particularly it is important to be able to regulate the speed of application, the evenness of the applied coating and the drying time of this. To achieve this, it has been found that an aerosol shower with a special composition is effective in reducing the activity of the mites and in combating the mites' waste.

A control or a regulation of the activity of the mites includes a control of both biological and physical activity for said mites and their waste, and this includes their outer chitinous skeleton and their ex-crime.

It has been found that in order to achieve the best control of the mites' activity can be achieved by changing the micro environment in certain substances where traditionally there is a high density of mites, and this can be done with a coating composition that tends to isolate the mites and/ or their exoskeleton and their excrement. It has also been found that this type of control or control reduces allergic reactions to a significant extent. If a suitable substance is chosen for

to isolate the mites and their waste, you will also achieve that other critical environmental factors such as the humidity level and nutrient availability can also be changed and this will further contribute to a better control or combating of the mites' activity.

Nutrients for mites include human skin waste, dander, dust fibers and food particles. An isolation of mites from these critical nutrients is achieved by coating certain substances found in ordinary houses, where mites tend to live and reproduce. This coating will then form a barrier on the fabric between the present mites and volatile nutrients which tend to accumulate on these substances after treatment.

Optimal substances for combating and regulating the activity of mites thus include coating compositions which: (a) limit the mobility of mites and the mites' waste, (b) maintain a microenvironment with reduced humidity around the mites, and (c) isolate and/or prevent the mites from critical

nutrients, and

(d) does not alter substance li gli et en on the host substrate,

and

(e) interrupts' normal use of the host substrate in a

minimum period of time.

It should be obvious that a good microenvironment for mites is typical fabric surfaces of the type found in ordinary houses. A treatment of these surfaces will thus be the most effective means of combating and/or regulating the activity of mites.

Compositions according to the present invention which are suitable for combating or controlling allergens in fabrics include an aqueous, film-forming composition under pressure with the following properties:-(a) a minimum film-forming temperature (MFT)

under approx. 30°C,

(b) contains a polymer or polymers with a glass transition temperature (Tg) of less than about 20°C, and (c) contains a volatile organic solvent

part, such as a low-molecular alcohol,

(d) provides a film which is hydrophobic, flexible, continuous and which can be removed from the substrate with detergent and water, and (e) can be spread from an aerosol container so that essentially a continuous film is formed on the substance, and where the film becomes so dry that it can be touched within a couple of minutes, and where the mite waste present is essentially rendered immobile.

Several applications of the type of coating described above on certain substances in the house have been shown to significantly reduce the activity of mites and their waste with a corresponding reduction in the allergy potential of these substances.

The coating

The present invention describes the combating and control of allergens by periodically coating certain types of substances with an aqueous, film-forming composition under pressure, and where the resulting film:-(a) has a minimum film-forming temperature (MFT)

of under approx. 30°C,

(b) contains polymers with a glass transition temperature (Tg) of less than about 20°C, and (c) forms a generally substantially continuous film which

is dry within minutes..

These aqueous film-forming compositions are applied to the entire fabric surface and wet the mites and their waste. Once the water and organic solvent have evaporated, you will have a continuous polymeric film that has coated the mites and their waste and binds them to the fabric.

.Films according to the present invention can generally be described as:-

(a) hydrophobic,

(b) bendable,

(c) continuous, and

(d) auto-dissolving.

The coating compositions of the present invention are only effective as long as dust mites and their waste are immobilized and the mites are kept under less than optimal growth conditions. Thus, for example, it is critical in the present invention that the film applied to different substances must be hydrophobic. This means that the film itself must not absorb moisture and consequently under support the mites' activity.

It has also been found that it is critical for combating or controlling the mites' activity in the substances that the film is self-dissolving. According to the present invention, the applied films can thus be dissolved with another coating composition of the invention when this is applied to the fabric. This auto-dissolving property is a function of the solubility of the polymer in the composition and the aerosol application methods. The pH of the coating composition may also be a factor in that regard.

The coating compositions under pressure according to the present invention provide flexible films which adhere to the various substances being treated. Usually the films will be from approx. 0.01 to approx. 1 (one) micron in thickness. In the preferred embodiment of the invention, the films will be from approx. 0.0025 mm to approx. 0.0125 mm thick. The films have an MFT of less than approx. 30°C, and are generally substantially continuous when they are formed at room temperature conditions, provided that the fabric surface is generally substantially completely moistened with the aerosol shower.

Limiting the movement of mites and mite waste The connection between mites and house dust allergy is well documented. However, it is not known how the mites relate to the allergic factors. There are three systems by means of which mite products are believed to be deposited in house dust, and in each of these systems the waste is easily mobile and has in itself a tendency to become airborne either as such or as part of a dust fibre. r. These systems are the following:-(1) the integument system, which contributes to the shedding of skin, fluids in connection with skeletal change and glands with secretions; (2) the reproductive system provides eggs, fluids associated with fertilization, and other compounds produced by egg laying and copulation; and (3) the intestinal canal system contributes to excrement with various components, as well as an intestinal lining that is very similar to a peritropic membrane.

It is thus obvious that a. combating and controlling these types of waste is achieved according to the present invention by applying a coating composition which binds the waste to the substance, thereby preventing or reducing the mobility of the waste. The coating compositions which are under pressure provide a quick-drying film which is essentially continuous and which almost immediately upon application renders the waste immobile in the fabric. Furthermore, coatings according to the present invention will be flexible and they will thus retain their continuity and capture of waste even when the material is bent. The net effect of treating fabric infested with mites and waste using the present compositions is to reduce the number of living mites in the fabric. Secondarily, the coated fabrics will essentially become impermeable to mites that might try to reinfect the fabric. Consequently, the fabric surface will no longer be an ideal microenvironment for mite activity and the mites tend to seek other environments, thereby reducing the allergy potential of the treated fabrics.

Maintenance of a rnil. lake with reduced humidity Population growth in mites is related to the absolute humidity in the air both indoors and outdoors, and almost any change in humidity is followed by a change in the number of mites and their activity.

It has been established that standardized female North American house dust mites have a constant equilibrium hot mass which is independent of the water vapor activity in the surrounding environment as long as this is above the critical equilibrium activity (CEA=0.70 at 25°C .) When the mites are kept in an environment where the water vapor activity is below the CEA, then. the rate of evaporation will be greater than the rate of absorption, and there will be a net loss of water as long as this condition is maintained.

It has also been established that the rate of water loss for mites kept in a dehydrated state is inversely proportional to the water vapor activity of the air. Thus, it has been possible to find that for water bird activities on. 0.5^5»0.225 and 0.00, then the rate of water loss will respectively be 1.11, 1, k0 and 1.77$> per hour at 25°C. Mean survival times for these dehydrating activities are 6S>t55°S ^3 hours, respectively. Standardized females contain 81% water by weight, and they can tolerate water loss of up to 46.5% before death occurs.

It should thus be obvious that coating substances with a high density with compositions under pressure according to the present invention will very effectively control the microenvironment of the mites and thereby reduce the niidd populations. This fighting or control can at least be attributed to the hydrophobic nature of man. finds on the continuous and flexible films that apply the fabric. After air-drying, these coatings will produce films that have very low water tension. Thus, these films will tend to maintain a humidity level that is less than that necessary for maintaining the activity of the mites, i.e. a CEA of less

than 0.7 at 25°C. This will result in an environment that is hostile to mite activity.

Isolation of mites from critical nutrients House dust mites prefer nutrients such as human skin waste, dander, dry hair, vegetable fibers such as lint, yeast and gelatin. Substances where mites tend to gather and which are coated with coating compositions under pressure according to the present invention have been shown to provide limited availability of such nutrients for said mites. As the coating compositions in themselves are not a nutrient for the mites, the continuous coating compositions will tend to regulate the activity of the mites which are not immobilized by starving them out.

The polymer

Polymers suitable for pressurized coating compositions of the present invention can generally be described as alkali- or acid-soluble, having a glass transition temperature of less than about 20°C and able

to form a film at less than 30°C. The preferred polymers according to the invention will generally have a relatively low molecular weight. Such polymers include acid-functional or base-functional monomers and monomers containing a vinyl group. Suitable polymers containing monomers can

further described as acid monomers, basic monomers, soft monomers and possibly hydrophobic monomers.

Soft monomers are the monomers that give flexible or pliable homopolymers with a brittleness point of less than approx. 20°C. Preferred soft monomers are vinyl acetate, the alkyl esters of acrylic acid, where said alkyl group has from 1 to 12 carbon atoms, such as methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate and lauryl acrylate; as well as higher alkyl esters of methacrylic acid where said higher alkyl group has from 2 to 12 carbon atoms, such as butyl methacrylate, 2-ethylhexyl methacrylate and lauryl methacrylate. The preferred soft monomers are ethyl acrylate and butyl acrylate.

Acidic monomers are monoethylenically unsaturated compounds that have at least one, and preferably only one, carboxylic acid group. Examples of such monomers include acrylic acid, methacrylic acid, itaconic acid, maleic acid and crotonic acid; monoalkyl esters of itacone and maleic acids where said alkyl group has from 1 to 8 carbon atoms, such as methyl, ethyl, butyl, hexyl and octyl. The preferred acidic monomers are acrylic and methacrylic acid.

Basic monomers are monoethylenic unsaturated compounds having at least one, and preferably only one base functional group. Examples of such monomers include dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, t-butylaminoethyl nitacrylate, t-butylaminoethyl acrylate, diethylaminoethyl methacrylate, diethylaminoethyl acrylate, 2-vinylpyridine, dimethylaminophenyl acrylate, vinylamine and ethyleneimine.

The preferred basic monomers are t-butylaminoethyl methacrylate and dimethylaminoethyl methacrylate.

Suitable hydrophobic monomers which can be included in the acrylic polymer are lower alkyl methacrylates where said lower alkyl group has from 1 to 3 carbon atoms, such as methyl methacrylate, ethyl methacrylate and isopropyl methacrylate; cycloalkyl acrylates and methacrylates where said cycloalkyl group has from 5 to 7 carbon atoms, such as cyclohexyl acrylate and cyclohexyl methacrylate; as well as hard vinyl monomers such as styrene. The preferred hydrophobic monomers are styrene and lower alkyl methacrylates, especially methyl methacrylate.

Listed in Table I below are examples of preferred acid-functional polymers that can be used in coating compositions under pressure according to the present invention. The composition of the polymers is stated in weight percent of the monomers present. In addition to this, the glass transition temperature Tg of these polymers is shown. It is understood that a glass transition temperature range of -9°C to 10°C defines polymers that provide flexible films that do not crack when the substrate is bent.

Listed in Table II below are examples of preferred base-functional polymers which can be used in the present compositions. The composition of the polymers is given in weight percent of the monomers present. In addition, the glass transition temperature Tg for these polymers is shown.

Processes for the preparation of the preferred polymers that can be used, in coating compositions under pressure according to the present invention, are well known and generally can. they are produced by a. addition- or emu ls j onspor-. lymeris ering. Thus, the polymers in Table I can be prepared in the following manner. For every 100 parts of monomer used, 3 parts of a surfactant such as sodium lauryl sulfate and 0.5 parts of a starting compound such as ammonium persulfate are mixed with 300 parts of distilled water. Emulsion polymerization is carried out by heating the sodium lauryl sulfate in water to 80°C. under an inert gas blanket in a reactor equipped with a stirring mechanism. The ammonium persulphate is first added, after which the mixture of monomers is added to the aqueous mixture over the course of an hour. The reaction mixture is then held at the reaction temperature for one hour and then cooled.

Automatic resolution

An auto-dissolution is the property of the dried film which allows the film to completely or partially redissolve when exposed to a subsequent application of the film forming composition. That property is necessary to achieve optimal control or regulation of the mites' waste and the mites themselves in the substance that is. exposed to a continuous contamination of dander and other nutrients that attract mites. Such places include sheets, pillowcases and upholstered furniture.

The auto-dissolution or the self-dissolution process itself regulates an amount of film which is again deposited on the substance by repeated applications of compositions according to the present invention. Thus will. not only mites and mite waste are captured, but also contaminants such as dandruff. Compositions according to the present invention have se.lv solubility when the polymer contains a suitable amount of pH-sensitive monomers and hydrophobic monomers1, so that by neutralizing the pH-sensitive part of the polymer. the latter will change from a state with respect to insolubility in an aqueous medium to a state that has solubility. This transition is marked by changes in the properties of the aqueous polymer composition such as changes in viscosity and/or changes in optical density. The pH-sensitive monomers are grouped into acid monomers as listed in Table I and the basic monomers are as listed in Table II. In addition to this, the degree of neutralization of the pH-sensitive groups found in the polymer will also affect the degree of self-dissolution exhibited by the composition.

Auto-dissolve liglien or self-dissolve liglien is achieved with the help of the polymers in table I by adding suitable amounts of alkali, e.g. ammonium hydroxide, morpholine, triethanolamine, sodium hydroxide or other commonly known bases, whereby a solution with a resulting pH of between 7 and. 10.

In a similar way, self-solubility can be produced with polymers in table II by adding suitable amounts of acids, for example acetic acid, citric acid, phosphoric acid, hydrochloric acid or other known acids, so that you get. a solution with a pH between approx. 7°S approx. k.

The solvent

The aqueous film-forming compositions according to the present invention are applied to the fabric surface and moisten mites and mite waste. To get optimal control, the film should dry within a few minutes. Preferably, the solution dries within five minutes when it is showered on the fabric, whereby a polymeric film is obtained which has moistened the mites and the mite waste and thereby binds them to the fabric. It is therefore critical for the present purpose that the coatings applied to the substrate dry relatively quickly. It has been found that the addition of relatively volatile organic solvents such as low molecular weight alcohols will accelerate the drying rate. Preferred alcohols in this regard include ethyl, isopropyl, isobutyl and tertiary butyl alcohol. Usually, the organic solvent mite1 will amount to approx. 5 to approx. 50 percent by weight, preferably from approx. 5 to approx.

25 percent by weight of the total composition.

Examples of compositions of film-forming compositions which are suitable for coating compositions under pressure according to the present invention are indicated in Table III.

The fuel

It is critical for the purpose of the present invention is that the film-forming composition lean is applied to the fabric in a regulated manner and that the dispersed material is dried so that it can be touched shortly after application, for example within three to fifteen minutes. It has been found that the sprayed-on composition does not need to penetrate deeply into certain substances, e.g. of the type found on upholstered furniture, bed mats etc., in order to be effective in controlling and combating mites. In reality, overwetting the fabric will have detrimental effects such as prolonged drying time, and this will reduce the composition's ability to immobilize mites. In addition to this, the physicality of the treated fabric can also change as a result of overwetting. It has thus been found that the method of application itself is closely related to the overall effect of the present invention. The present invention thus describes applying the film-forming composition by means of an aerosol propellant which is under pressure.

The preferred propellants are liquid hydrocarbons which are gaseous at room temperature, liquid halogenated hydrocarbons which are gaseous at room temperature and inert compressible gases. Preferred hydrocarbon propellants include saturated aliphatic hydrocarbons such as propane, butane, isobutane, n-pentane and isopentane. Preferred halogenated hydrocarbons include dichlorodifluoroethane, dichlorotetrafluoroethane, trichlorotrifluoroethane and difluoromethane. Preferred inert compressible gases that can be used as propellants include nitrous oxide, nitrogen and carbon dioxide. Mixtures of two or more propellants can also be used. Other usable propellants include normal and branched hexanes and heptanes.

The propellant is preferably used in an amount that is sufficient to expel the entire contents of the container. Generally, a propellant amount varying from 5 to 50 percent by weight, preferably from 5 to 20 percent by weight, of the total composition will thus be used. The composition will usually be expelled from the container in the form of a foam or a fine surface shower. The pressure in the container will usually be off. 0.35 to 5>27 kg. per cm above atmospheric pressure.

Coating compositions under pressure Coating compositions under pressure according to the present invention include the following:

(a) a polymer,

(b) water,

(c) an organic solvent, and (d) a propellant.

The following examples illustrate embodiments of the invention. It is understood that these examples are only illustrative and that the invention as such is not limited by what is stated in these examples.

To achieve optimal properties of the propellant, small amounts of a propellant-stabilizing surfactant are often added to the composition, typically from approx. 1 to approx. 5 percent. Preferred stabilizing surfactants in this respect are well known, and can for example be polyoxyethylene sorbitan alkyls, alkyl phenoxy polyethoxy ethanols, polyoxyethylene alkyl esters and alkyl aryl polyether alcohols.

Application of the coating

It has been established that arthropods such as different types of mites allow a t to grow up tp is in ode which is annually dependent on the climate. For example, in temperate humid climates you will have a peak growth period for these mites from July to October. In addition to this, it has been observed that there is a high correlation between maximum indoor humidity and live mites present during these peak growth periods.

It has now been found that certain optimal memory host substances found in houses are treated with the composition according to the present invention before such peak growth periods, then mite populations and waste from these will be significantly reduced and a corresponding reduction in the allergy potential of these substances will be obtained. As described in Table IV, certain critical substances found in houses were thus selectively treated before and during a growing period in order to control and regulate the mites' activity and to avoid reinfection by mites, thereby reducing the allergy potential of the treated substances.

There are certain areas in a typical house that are more conducive to insidious activity than others. Said areas include mattresses, underlays, upholstered furniture and carpets. The dense mite populations that are often found in mattresses are partly due to an excess of human skin waste and plant fibre, and these are known preferred nutrients for mites. In addition to this, a mattress will provide the best optimal and constant humidity conditions available in the house. It has been found that the mites mostly live.- in over- -• .

the surface layer of the mattress. It is well known that mattresses can

be a reservoir for mite activity in most houses, and that a mattress can be a source of mite reinfection. A preferred area for treatment according to the present invention is thus in the entire mattress surface and bed base which

like that. Preferably, this treatment should take place periodically throughout the year.

Examples 2 3 to 31

Various coating compositions under pressure are described in Table IV below, and these were applied to various fabric surfaces. These pressurized coatings provide quick-drying films that are hydrophobic, flexible, continuous and self-dissolving.

It is clear from the following examples that different coatings under pressure can be applied to a number of different substances in order to thereby regulate mite activity and thus reduce the substance's allergy potential. The. it is clear from these examples that a system has been developed for combating and controlling mites in a typical domestic environment. Such a system requires periodic treatment of certain fabric surfaces and less frequent treatment of others. It is believed that if these treatments are carried out on all critical substances in a house,

then you will significantly reduce mite activity. and thereby the allergy potential in such environments.

The following table indicates application examples of compositions from Table III. It is understood that the compositions set forth in Table III as well as the applications are typical, but are not exhaustive or exclusive in any way.

Claims (9)

1. Article suitable for the regulation of allergens in substances, characterized by consisting of: (a) a container under pressure, in which there is1 (b) a. aqueous film-forming coating composition (c) an organic solvent, and (d) a propellant; and where the composition, when this is applied to a substrate by spraying from the aerosol container, quickly dries, so that a substantially continuous film is obtained, and where said composition has a minimum film-forming temperature of below approx. 30°C., and includes a hydrophobic polymer with a glass transition temperature of less than approx. 20°C. 2. Article according to claim 1, characterized in that said polymer is composed of acid-functional monomers and monomers containing a vinyl group. 3. Article according to claim 2, characterized in that said carboxylic acid monomer is selected from the group consisting of methacrylic acid, acrylic acid and mixtures thereof, and that the monomer containing a vinyl group is selected from the group consisting of ethyl acrylate, methyl acrylate, n-butyl acrylate and mixtures thereof . k. Article according to claim 3> characterized in that the polymer includes an effective amount of an acid monomer, so that said polymer becomes water-soluble upon addition of a base, selected from the group consisting of ammonium hydroxide, morpholine, sodium hydroxide and triethanolamine. 5. Article according to claim 4, characterized in that the film has a minimum film-forming temperature of between -1 and 14°C. , that the polymer component in the film has a glass transition temperature of between -9 and 14°C, that the composition has a pH from 7 to 10, and that the film is self-dissolving. 6. Article according to claim 1, characterized in that said organic solvent is a low molecular weight alcohol. 7. Article according to claim 6, characterized in that said low molecular alcohol is present in amounts of between 5 and 25 percent by weight and is selected from the group consisting of ethyl, isopropyl, isobutyl and tertiary butyl alcohol. 8. Article according to claim 1, characterized in that the coating composition contains a polymer composed of monomers containing a basic functional group and monomers containing a vinyl group. 9. Article according to claim 8, characterized in that the polymer is composed of amino basic monomers, soft monomers and hydrophobic monomers.