Composition for impregnating materials to shield against the effects of alternating electromagnetic fields, its application in coating/impregnating fibrous and/or porous matrices and materials containing the same

Abstract

A composition for application to a base material, rendering the base material able to shield alternating electromagnetic fields in the range from low frequencies up to radio frequencies, includes an aqueous solution of a hydratable salt; a modifier selected from the group consisting of acrylic dispersions, styrene-acrylic dispersions, silicone emulsions and combinations thereof; and an enhancing additive selected from the group consisting of surface active agents, aluminosilicates, silicates, soluble calcium compounds, insoluble calcium compounds, metal oxides, metalloid oxides and combinations thereof. The alternating field is shielded at least in the range from 10.sup.2 Hz to 10.sup.6 Hz. The composition may be used to coat/impregnate fibrous and/or porous matrices.

Claims

1. A composition for application to a base material to render the base material able to shield alternating electromagnetic fields, the composition comprising: an aqueous solution of a hydratable salt; a modifier selected from the group consisting of acrylic dispersions, styrene-acrylic dispersions, silicone emulsions and combinations thereof; and an enhancing additive selected from the group consisting of surface active agents, aluminosilicates, silicates, soluble calcium compounds, insoluble calcium compounds, metal oxides, metalloid oxides, and combinations thereof, wherein the base material is shielded from alternating electromagnetic fields at least in the range of 10.sup.2 Hz to 10.sup.6 Hz.

2. The composition of claim 1, wherein the surface active agents are compounds selected from the group consisting of detergents, surfactants, emulsifiers, amphiphiles, defoamers, dispersants, and glycols.

3. The composition of claim 1, wherein the aluminosilicates and silicates are compounds selected from the group consisting of bentonite, kaolin, and talc.

4. The composition of claim 1, wherein the insoluble calcium compounds are compounds selected from the group consisting of powdered limestone and dolomite.

5. The composition of claim 1, wherein the composition contains compounds selected from the group consisting of gypsum, calcium hydroxide, and Portland cement.

6. The composition of claim 1, wherein the composition contains a resin selected from the group consisting of alkyd resin in an organic solvent, epoxide resin in a solid state or a solution, phenol formaldehyde resin in ethanol, and silicone resin in a solution or a suspension.

7. An electric field shielding construction material comprising the composition of claim 1.

8. An EMF shielding material, comprising: a matrix material; and a composition according to claim 1 coated on or impregnated in the matrix material.

9. The EMF shielding material of claim 8, wherein the composition coated on or impregnated in the matrix material forms a construction material selected from the group consisting of primers, plaster/paint primers, paints, plastering mortars, laminates used in constructions, and textiles.

10. Electric field shielding furniture material comprising the composition of claim 1.

11. Electric field shielding clothing material comprising the composition of claim 1.

12. Electric field shielding textile material comprising the composition of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The Examples of the invention are presented in the figures, in which:

(2) FIG. 1 is a graph showing the absorption of an electric field using an impregnated polyester material according to the prior art;

(3) FIG. 2 is a graph showing the dependence of the real and imaginary part of permittivity (, ) and dielectric losses (tan ) on frequency for a foil-screen produced on a production line;

(4) FIG. 3 is a graph showing the dependency of shielding efficiency on frequency for various screens;

(5) FIG. 4 is a graph showing a comparison of shielding efficiency dependence on frequency for a screen in the form of 12 m thick aluminum foil and a screen containing gel and an aqueous solution of NH.sub.4Cl and MgCl.sub.2 with the addition of SiO.sub.2;

(6) FIG. 5 is a bar graph showing a comparison of the dependence of shielding efficiency on the electric and magnetic component for a gel screen at a frequency of 27 MHz;

(7) FIG. 6 is a graph showing a comparison of the dependence of shielding efficiency on frequency for a screen containing an aqueous solution of gel NH.sub.4Cl and MgCl.sub.2 with the addition of SiO.sub.2 and a screen additionally containing gel gellan;

(8) FIG. 7 is a graph showing a comparison of the dependence of shielding efficiency SE on frequency for an electric field determined as SE=(E.sub.0E.sub.e)/E.sub.0 as a percentage (where E.sub.0 is the electric field strength in front of the screen and E.sub.e is the electric field strength behind the screen) for screens with a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO.sub.3) impregnated with various aqueous solutions of hydratable salts with the addition of bentonite (specified percentage concentration of additives are in wt percentage); and

(9) FIG. 8 is a graph showing a comparison of shielding for the invention described in patent application PL387274 and a composition according to the present invention with additions for low humidity environments.

DETAILED DESCRIPTION

Example 1

(10) In order to illustrate the advantages of the invention, its performance was compared with a prior known solution. As typical prior art for the present invention, the invention shown in patent application PL387274 is shown in FIG. 1, where a hydrophilic textile made of polyester was impregnated with an MgCl.sub.2 solution at a temperature not exceeding 117 C. in order to obtain an EF shield. The solution was prepared in a weight ratio MgCl.sub.2.6H.sub.2O:H.sub.2O equal to 1:20 with the addition of a poly(vinyl acetate) dispersion belonging to the group of polymers used for applying finishes to textiles in order to maintain the bonded hydrate. Subsequently, after draining, the fabric was dried and left to achieve ambient humidityin order for separation of free water from the material to occur. After drying, the fabric absorbed the electrical component of electromagnetic waves in the low frequency band. The electric field shielding ability was determined using a Maschek ESM-100. A C&C generator FG-220C was used as the source of the alternating electric field. Measurement results from 10.sup.1 to 510.sup.4 Hz are presented in FIG. 1 illustrating the dependence on the frequency of the electric field strength measured with an electric field meter for the modified fabric obtained according to the procedure described in Example 1 placed between the field meter and the antenna connected to the generator (see the curve with measurement points marked with squares, and the control measurement without modified fabric with measurement points marked with triangles). FIG. 8 shows a comparison of the shielding for the invention shown in patent application PL387274 and the composition according to the present invention containing 2.2% of MgCl.sub.2 with the addition of a 20% acrylic dispersion and 5% silica at a relative humidity in the range of 25% to 37%.

(11) Examples of the invention are presented in the Tables and in the figures presenting the measurement results of shielding efficiency. The Tables and figures present the measurement results of shielding efficiency (SE) SE=(E.sub.0E.sub.e)/E.sub.0 (where E.sub.0 is the electric field strength in front of the screen and E.sub.e is the electric field strength behind the screen) or shielding efficiency in dB. Different matrices were impregnated with 16 g/m.sup.2 of various compositions and then after 24 h the shielding efficiency was measured. The drying time of the impregnated matrix was chosen to be excessive, since as early as 10 h no changes in SE were observed. The polymers used in these examples were dispersions with a dispersed phase:water ratio of 1:1. Electric field strength was measured at ambient temperature using an electromagnetic field meter by Maschek Elektronik, ESM-100 3D H/E, in the frequency range from 5 Hz to 400 kHz. A rod antenna connected to a C&C FG-220C generator was used as the source of the alternating electric field. For a polypropylene nonwoven impregnated with a shielding component material, dielectric measurements were also carried out at ambient temperature using a broadband dielectric spectrometer by Novocontrol GmbH in the frequency range from 10.sup.2 to 10.sup.7 Hz. Table 1 shows the increase of shielding efficiency of a model wall made of a matrix (PE+CaCO.sub.3) after impregnation with various impregnating solutions: an aqueous solution of MgCl.sub.2, a mixture of an aqueous solution of MgCl.sub.2 with various concentrations of a PVA dispersion, and a mixture of an aqueous solution of MgCl.sub.2 with a 20% PVA dispersion and various modifiers. The first four results and FIG. 1 illustrate the invention shown in Polish patent application PL387274. Depending on the modifier used, there was an increase in the shielding efficiency (SE) and significant broadening of the shielding frequency range towards the higher frequencies in comparison to the closest prior art (see results starting from No. 5 in Table 1), while the 20% concentration of added dispersion of PVA is close to an optimum concentration. The further results in Table 1 show the effect of modifiers: bentonite, sodium aluminosilicate, kaolin, titanium white, silica, talc, lime powder (natural and synthetic), dolomite powder, defoamer (emulsion of silicone oil), dispersant (sodium polyacrylate), poly(vinyl alcohol), carboxymethylcellulose and biocide (Kathon 886). Table 1 shows the shielding efficiency SE of an electric field determined by SE=(E.sub.0E.sub.e)/E.sub.0 as a percentage (where E.sub.0 is the electric field strength in front of the screen and E.sub.e is the electric field strength behind the screen) for a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO.sub.3), the matrix impregnated with a mixture of an aqueous solution of MgCl.sub.2 with a PVA dispersion and various modifiers (specified percentage concentrations of additives are in wt percentage).

(12) TABLE-US-00001 TABLE 1 2 5 10 20 50 100 200 400 No. matrix (PE + CaCO.sub.3) + fillers kHz kHz kHz kHz kHz kHz kHz kHz 1 2.2% of MgCl.sub.2 aqueous 24.7 8.8 4.4 2.9 2.4 2.4 1.9 2.9 solution (aq. s.) 2 2.2% MgCl.sub.2 aq. s. + 0.1% PVA 53.2 30.0 14.9 8.5 5.4 5.6 6.1 8.2 dis. 3 2.2% MgCl.sub.2 aq. s. + 20% PVA 76.6 62.1 42.1 23.6 15.3 11.9 9.2 7.7 dis. 4 2.2% MgCl.sub.2 aq. s. + 95.4% 62.8 42.1 27.1 19.5 15.6 12.5 9.0 7.4 PVA dis. 5 no. 3 + 0.3% bentonite 97.8 95.9 94.1 92.2 85.7 77.3 65.3 52.9 6 no. 3 + 5% bentonite 97.2 95.8 95.0 92.2 81.3 70.6 51.0 30.0 7 no. 3 + 40% bentonite 82.9 64.4 43.9 24.6 8.9 4.1 3.1 4.2 8 no. 3 + 0.3% sodium 96.9 96.3 95.4 93.7 89.0 82.2 72.7 61.9 aluminosilicate 9 no. 3 + 5% sodium 95.2 93.0 91.1 85.3 72.0 59.9 36.6 19.5 aluminosilicate 10 no. 3 + 20% sodium 90.3 78.3 64.2 45.3 21.6 11.5 5.1 2.0 aluminosilicate 11 no. 3 + 0.3% kaolin 97.4 96.7 95.5 91.5 81.0 68.5 49.2 29.1 12 no. 3 + 5% kaolin 96.5 96.2 94.9 92.3 82.1 72.6 49.9 34.4 13 no. 3 + 20% kaolin 96.4 95.8 94.7 91.9 81.9 68.5 49.4 27.1 14 no. 3 + 0.3% titanium white 96.6 96.1 94.7 92.2 83.1 69.6 55.0 37.3 15 no. 3 + 20% titanium white 97.1 96.9 96.2 94.2 86.8 77.5 62.8 45.6 16 no. 3 + 40% titanium white 96.6 95.6 93.4 89.4 77.2 60.5 39.2 20.0 17 no. 3 + 0.1% silica 96.7 95.5 94.6 91.7 82.4 72.3 53.6 30.8 18 no. 3 + 5% silica 95.4 92.1 86.7 76.3 51.5 29.9 12.3 6.5 19 no. 3 + 10% silica 94.6 90.9 86.5 76.1 53.0 33.5 13.2 9.2 20 no. 3 + 0.3% synth. lime 96.7 95.8 94.2 90.9 80.2 66.4 48.9 35.1 powder 21 no. 3 + 5% synth. lime powder 96.8 96.2 95.4 93.0 85.9 76.6 61.7 46.5 22 no. 3 + 20% synth. lime 96.6 95.4 93.4 89.4 76.0 59.6 40.8 25.3 powder 23 no. 3 + 0.3% nat. lime powder 96.8 96.2 95.5 92.9 84.3 72.6 55.7 35.8 24 no. 3 + 5% nat. lime powder 96.5 95.8 94.9 93.1 87.1 76.6 65.9 53.5 25 no. 3 + 20% nat. lime powder 96.8 96.3 95.6 93.9 87.5 79.4 65.7 51.8 26 no. 3 + 0.3% dolomite powder 97.2 96.5 94.8 90.9 79.3 64.6 44.4 25.2 27 no. 3 + 5% dolomite powder 97.0 96.4 95.9 93.2 86.2 78.5 65.5 49.1 28 no. 3 + 20% dolomite powder 96.9 96.8 96.2 94.9 89.2 80.9 68.6 54.2 29 no. 3 + 0.3% talc 96.9 96.1 94.9 91.4 80.8 69.5 51.4 30.3 30 no. 3 + 5% talc 96.9 96.5 95.8 94.3 88.1 79.3 67.5 55.7 31 no. 3 + 20% talc 96.1 93.7 90.1 84.0 69.5 52.3 31.4 16.4 32 no. 3 + 0.01% defoamer 96.8 96.2 95.2 92.8 84.9 72.3 55.2 37.1 33 no. 3 + 0.6% defoamer 96.3 94.2 90.3 83.2 64.5 42.1 20.7 9.8 34 no. 3 + 5% defoamer 67.6 48.5 32.4 23.3 16.2 14.6 11.1 11.4 35 no. 3 + 0.01% dispersant 95.8 95.3 94.4 91.6 82.9 71.8 53.8 35.1 36 no. 3 + 0.6% dispersant 97.0 94.8 92.0 86.3 72.0 54.6 32.4 18.3 37 no. 3 + 5% dispersant 87.7 75.0 57.6 40.6 13.6 4.7 2.7 4.7 38 no. 3 + 0.1% poly(vinyl 95.6 92.1 86.5 75.2 52.7 32.7 16.2 8.4 alcohol) 39 no. 3 + 0.3% poly(vinyl 96.0 95.0 93.0 88.1 76.7 60.1 38.5 18.9 alcohol) 40 no. 3 + 5% poly(vinyl alcohol) 96.1 93.8 89.7 82.4 63.6 42.9 22.8 11.1 41 no. 3 + 0.1% 96.7 94.4 90.1 81.5 65.1 45.8 27.4 16.7 carboxymethylcellulose 42 no. 3 + 0.3% 96.4 93.9 89.6 80.8 60.7 39.9 21.3 10.4 carboxymethylcellulose 43 no. 3 + 1% 91.3 81.7 66.9 46.9 25.7 14.0 10.9 8.1 carboxymethylcellulose 44 no. 3 + 0.01% BIOCIDE 95.7 92.6 88.3 79.7 61.5 42.2 22.3 11.3 45 no. 3 + 0.1% BIOCIDE 96.1 95.0 93.2 87.4 75.8 59.2 33.9 17.0 46 no. 3 + 0.6% BIOCIDE 95.2 94.1 91.8 85.8 70.8 52.2 27.9 14.4

Example 2

(13) The tests carried out were as for Example 1, and Example 2 illustrates test results of EF shielding efficiency depending on frequency for a shield in the form of a polyethylene foil matrixed with calcium carbonate (CaCO.sub.3) and impregnated with a mixture of an aqueous solution of MgCl.sub.2 with an acrylic dispersion and various modifiers. Table 2 shows the shielding efficiency SE of an electric field determined by SE=(E.sub.0E.sub.e)/E.sub.0 as a percentage (where E.sub.0 is the electric field strength in front of the screen and E.sub.e is the electric field strength behind the screen) for a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO.sub.3), the matrix impregnated with a mixture of an aqueous solution of MgCl.sub.2 with an acrylic dispersion and various modifiers (specified percentage concentrations of additives are in wt percentage).

(14) TABLE-US-00002 TABLE 2 2 5 10 20 50 100 200 400 No. matrix (PE + CaCO.sub.3) kHz kHz kHz kHz kHz kHz kHz kHz 1 2.2% MgCl2 Aqueous 24.7 8.8 4.4 2.9 2.4 2.4 1.9 2.9 solution (aq. s.) 2 2.2% MgCl.sub.2 aq. s. + 0.1% 25.0 7.9 3.8 2.5 2.5 2.6 2.3 3.3 acryl. dis. 3 2.2% MgCl.sub.2 aq. s. + 20% PVA 35.6 16.5 10.5 8.1 6.6 5.6 4.3 4.3 dis. 4 2.2% MgCl.sub.2 aq. s. + 95.4% 31.2 9.4 3.8 2.1 2.4 2.5 2.3 3.2 acryl. dis. 5 no. 3 + 0.3% bentonite 47.7 34.7 23.2 11.7 6.7 5.7 4.4 3.1 6 no. 3 + 1% bentonite 73.0 49.0 30.6 13.1 6.0 2.9 2.7 3.6 7 no. 3 + 2% bentonite 67.3 41.6 21.4 12.8 6.1 4.8 4.7 5.1 8 no. 3 + 5% bentonite 64.3 37.5 22.0 13.7 8.4 6.3 4.4 4.5 9 no. 3 + 40% bentonite 81.7 62.6 43.7 26.4 12.9 6.9 4.3 4.7 10 no. 3 + 0.3% sodium 47.4 27.1 19.6 15.3 12.3 9.8 6.8 7.0 aluminosilicate 11 no. 3 + 5% sodium 63.4 37.3 23.7 15.4 9.8 7.3 5.4 5.1 aluminosilicate 12 no. 3 + 20% sodium 88.0 72.6 55.1 32.5 11.1 5.0 2.4 3.1 aluminosilicate 13 no. 3 + 0.3% kaolin 57.5 38.1 26.5 16.9 9.1 6.1 2.8 3.3 14 no. 3 + 5% kaolin 88.6 75.8 58.0 35.7 13.0 5.3 2.1 3.0 15 no. 3 + 20% kaolin 97.6 96.6 94.2 89.3 75.2 56.9 33.6 14.8 16 no. 3 + 0.3% titanium white 63.5 41.0 28.6 20.6 13.5 8.8 4.9 3.3 17 no. 3 + 20% titanium white 79.1 55.3 34.0 16.3 5.9 3.1 2.0 3.7 18 no. 3 + 40% titanium white 97.6 95.5 92.0 84.7 64.9 43.3 20.2 7.4 19 no. 3 + 0.1% silica 39.9 17.8 9.6 5.3 3.5 3.0 2.0 4.1 20 no. 3 + 2% silica 70.6 46.3 27.4 12.8 7.8 5.6 4.5 7.1 21 no. 3 + 5% silica 96.6 94.7 91.0 83.3 63.8 41.1 18.4 6.7 22 no. 3 + 10% silica 96.3 96.0 95.1 93.0 86.3 76.0 59.7 42.5 23 no. 3 + 0.3% nat. lime powder 58.6 31.4 15.5 7.4 3.6 2.6 2.0 4.2 24 no. 3 + 5% nat. lime powder 91.6 82.4 68.4 48.7 25.5 14.1 6.5 5.3 25 no. 3 + 20% nat. lime powder 85.4 67.7 49.3 30.5 17.3 12.2 8.6 8.1

Example 3

(15) The tests carried out were as for Example 1, and Example 3 illustrates test results of EF shielding efficiency depending on frequency for a shield in the form of a polyethylene foil matrixed with calcium carbonate (CaCO.sub.3) and impregnated with a mixture of an aqueous solution of MgCl.sub.2 with a styrene-acrylic dispersion and various modifiers. Table 3 shows the shielding efficiency SE of an electric field determined by SE=(E.sub.0E.sub.e)/E.sub.0 as a percentage (where E.sub.0 is the electric field strength in front of the screen and E.sub.e is the electric field strength behind the screen) for a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO.sub.3), the matrix impregnated with a mixture of an aqueous solution of MgCl.sub.2 with styrene-acrylic dispersion and various modifiers (specified percentage concentrations of additives are in wt percentage).

(16) TABLE-US-00003 TABLE 3 2 5 10 20 50 100 200 400 No. matrix (PE + CaCO.sub.3) kHz kHz kHz kHz kHz kHz kHz kHz 1 2.2% MgCl2 Aqueous 24.7 8.8 4.4 2.9 2.4 2.4 1.9 2.9 solution (aq. s.) 2 2.2% MgCl.sub.2 + 0.1% styr.-acr. 25.0 10.9 8.2 5.8 5.5 5.6 5.0 6.1 disp. 3 2.2% MgCl.sub.2 + 20% styr.-acr. 29.7 15.3 9.9 6.5 6.0 4.9 3.0 4.2 disp. 4 2.2% MgCl.sub.2 + 95.4% styr.-acr. 91.3 80.6 65.4 44.0 20.5 10.8 5.8 5.0 disp. 5 no. 3 + 0.3% bentonite 37.2 15.3 8.3 6.3 6.0 5.5 4.8 6.0 6 no. 3 + 5% bentonite 93.9 88.7 79.6 63.6 36.8 19.7 10.5 7.7 7 no. 3 + 40% bentonite 93.9 87.1 77.2 61.1 33.8 17.3 6.3 7.5 8 no. 3 + 0.3% sodium 59.4 35.1 20.1 12.8 8.9 7.1 5.8 6.4 aluminosilicate 9 no. 3 + 5% sodium 64.6 37.8 22.0 13.0 7.7 5.8 4.5 5.3 aluminosilicate 10 no. 3 + 20% sodium 83.5 62.5 41.6 20.2 7.2 4.9 4.0 4.9 aluminosilicate 11 no. 3 + 0.3% kaolin 27.7 9.3 4.6 3.2 3.1 3.1 2.7 3.5 12 no. 3 + 5% kaolin 56.8 30.6 20.0 12.8 9.5 9.1 7.4 8.7 13 no. 3 + 20% kaolin 96.4 94.6 90.2 82.2 62.3 40.4 20.5 10.2 14 no. 3 + 0.3% titanium white 47.2 24.0 13.7 9.0 6.7 5.6 4.7 5.3 15 no. 3 + 20% titanium white 97.0 94.9 91.4 84.2 64.8 42.8 21.5 9.9 16 no. 3 + 40% titanium white 95.9 94.7 92.2 87.1 72.4 52.3 28.9 12.3 17 no. 3 + 0.1% silica 42.2 19.7 10.7 5.8 4.1 3.5 2.7 3.3 18 no. 3 + 5% silica 96.4 96.1 95.0 92.4 84.4 72.5 53.7 34.2 19 no. 3 + 10% silica 96.1 94.3 85.6 83.5 65.1 43.7 23.3 10.8 20 no. 3 + 0.3% synth. lime powder 31.6 10.0 4.3 2.9 2.8 2.9 2.3 3.3 21 no. 3 + 5% synth. lime powder 70.0 45.9 29.1 18.1 11.1 8.0 5.7 5.9 22 no. 3 + 20% synth. lime powder 87.4 71.7 52.7 28.6 11.6 5.1 2.1 3.1 23 no. 3 + 0.3% nat. lime powder 38.3 14.7 6.8 4.2 3.3 2.9 2.0 3.2 24 no. 3 + 5% nat. lime powder 71.7 46.8 28.1 14.7 7.2 4.5 2.8 3.7 25 no. 3 + 20% nat. lime powder 84.0 67.6 50.0 32.0 15.1 7.3 4.1 4.2 26 no. 3 + 0.3% talc 36.3 15.9 9.1 5.8 4.7 4.1 3.4 4.7 27 no. 3 + 5% talc 70.1 46.9 29.8 16.0 6.3 2.7 1.1 1.5 28 no. 3 + 20% talc 74.0 55.6 42.7 32.9 23.8 16.9 10.4 6.6

Example 4

(17) The tests carried out were as for Example 1, and Example 4 illustrates test results of EF shielding efficiency depending on frequency for a shield in the form of a polyethylene foil matrixed with calcium carbonate (CaCO.sub.3) and impregnated with a mixture of an aqueous solution of MgCl.sub.2 with a silicone emulsion and various modifiers. Table 4 shows the shielding efficiency SE of an electric field determined by SE=(E.sub.0E.sub.e)/E.sub.0 as a percentage (where E.sub.0 is the electric field strength in front of the screen and E.sub.e is the electric field strength behind the screen) for a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO.sub.3), the matrix impregnated with a mixture of an aqueous solution of MgCl.sub.2 with a silicone emulsion and various modifiers (specified percentage concentrations of additives are in wt percentage).

(18) TABLE-US-00004 TABLE 4 2 5 10 20 50 100 200 400 No. matrix (PE + CaCO.sub.3) kHz kHz kHz kHz kHz kHz kHz kHz 1 2.2% MgCl.sub.2 Aqueous 24.7 8.8 4.4 2.9 2.4 2.4 1.9 2.9 solution (aq. s.) 2 2.2% MgCl.sub.2 aq. s. + 0.1% sil. 95.8 93.6 90.8 85.4 68.1 51.8 32.3 18.5 emulsion 3 2.2% MgCl.sub.2 aq. s. + 20% sil. 94.2 92.3 88.4 81.3 65.3 49.2 26.9 14.4 emulsion 4 2.2% MgCl.sub.2 aq. s. + 95.4% sil. 62.7 37.8 20.4 13.9 10.5 8.0 5.5 6.4 emulsion 5 2.2% MgCl.sub.2 aq. s. + 0.3% tit. 36.4 13.7 8.8 6.2 5.1 4.8 4.6 4.7 white 6 2.2% MgCl.sub.2 aq. s. + 20% tit. 38.1 20.3 12.7 8.5 7.7 5.7 4.2 4.2 white 7 2.2% MgCl.sub.2 aq. s. + 40% tit. 97.2 96.2 94.2 90.4 79.6 63.7 43.2 24.0 white

Example 5

(19) The tests carried out were as for Example 1, and Example 5 illustrates test results of EF shielding efficiency depending on frequency for a shield in the form of a polyethylene foil matrixed with calcium carbonate (CaCO.sub.3) and impregnated with an aqueous solution of MgCl.sub.2 and various modifiers. Table 5 shows the shielding efficiency SE of an electric field determined by SE=(E.sub.0E.sub.e)/E.sub.0 as a percentage (where E.sub.0 is the electric field strength in front of the screen and E.sub.e is the electric field strength behind the screen) for a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO.sub.3), the matrix impregnated with an aqueous solution of MgCl.sub.2 and various modifiers (specified percentage concentrations of additives are in wt percentage).

(20) TABLE-US-00005 TABLE 5 2 5 10 20 50 100 200 400 No. matrix (PE + CaCO.sub.3) kHz kHz kHz kHz kHz kHz kHz kHz 1 2.2% MgCl.sub.2 Aqueous 24.7 8.8 4.4 2.9 2.4 2.4 1.9 2.9 solution (aq. s.) 2 no. 1 + 0.3% bentonite 79.9 65.6 51.2 33.9 18.6 10.6 5.6 3.9 3 no. 1 + 5% bentonite 96.4 96.0 95.6 94.8 92.6 87.9 77.9 69.9 4 no. 1 + 40% bentonite 95.9 92.9 88.4 77.3 61.0 40.9 20.9 11.1 5 no. 1 + 0.3% sod.-alum. 53.2 28.6 12.8 3.4 3.1 2.4 1.4 2.0 silicate 6 no. 1 + 5% sod.-alum. silicate 21.1 8.3 3.0 0.3 1.9 1.1 0.9 0.9 7 no. 1 + 20% sod.-alum. silicate 18.3 4.1 0.4 0.2 0.2 0.2 0.1 0.2 8 no. 1 + kaolin 0.3% 90.9 84.1 79.3 75.9 68.5 55.9 40.5 30.6 9 no. 1 + 5% kaolin 96.0 94.8 92.9 89.2 80.2 68.2 52.9 43.3 10 no. 1 + 20% kaolin 97.3 97.1 96.8 95.9 92.4 86.3 76.8 67.0 11 no. 1 + 0.3% titanium white 86.3 79.7 73.9 62.7 40.3 21.9 8.5 4.2 12 no. 1 + 20% titanium white 95.5 92.4 86.5 75.8 52.1 28.0 12.1 8.1 13 no. 1 + 40% titanium white 97.1 96.0 93.6 89.5 76.4 58.8 42.4 26.4 14 no. 1 + 0.1% silica 87.3 79.5 69.6 54.1 32.5 15.8 6.6 2.7 15 no. 1 + 5% silica 73.4 52.7 34.4 18.9 10.9 7.2 4.9 4.5 16 no. 1 + 10% silica 72.6 51.1 33.4 16.7 9.2 5.2 2.8 2.0 17 no. 1 + 0.3% synth. lime 59.0 35.7 19.4 8.7 6.5 5.0 3.6 4.1 powder 18 no. 1 + 5% synth. lime powder 94.1 93.8 93.5 92.4 88.8 81.3 70.5 60.7 19 no. 1 + 20% synth. lime 96.8 96.2 95.2 93.1 87.5 78.7 66.4 52.7 powder 20 no. 1 + 0.3% nat. lime powder 61.7 45.0 26.9 13.7 8.5 6.0 4.2 4.7 21 no. 1 + 5% nat. lime powder 88.5 78.5 66.4 49.6 29.2 17.2 10.1 6.6 22 no. 1 + 20% nat. lime powder 96.8 96.4 95.8 94.2 90.8 85.2 77.1 65.1 23 no. 1 + 5% dolomite powder 85.0 76.1 66.6 50.3 28.4 14.9 7.3 6.5 24 no. 1 + 0.3% dolomite powder 76.6 63.4 48.8 29.6 15.2 7.9 3.8 3.4 25 no. 1 + 20% dolomite powder 96.4 96.3 96.3 96.1 94.9 93.2 90.4 82.8 26 no. 1 + 0.3% talc 76.6 59.6 43.6 23.7 12.4 6.6 3.1 2.1 27 no. 1 + 5% talc 96.5 96.4 96.3 95.7 93.0 87.6 77.4 70.0 28 no. 1 + 20% talc 96.1 95.6 95.0 93.3 87.4 78.0 61.7 48.7 29 no. 1 + 0.01% defoamer 39.9 17.5 8.1 4.4 4.3 3.3 2.5 2.8 30 no. 1 + 0.6% defoamer 86.1 77.7 69.9 56.2 33.5 16.4 4.8 2.2 31 no. 1 + 5% defoamer 56.8 33.8 19.8 9.6 6.3 3.7 1.4 0.9 32 no. 1 + 0.01% dispersant 48.0 20.9 8.2 2.1 3.1 2.6 2.2 2.2 33 no. 1 + 0.6% dispersant 78.0 65.4 50.5 31.6 17.8 9.5 4.5 2.8 34 no. 1 + 5% dispersant 80.3 68.6 54.0 36.2 17.2 7.5 3.0 1.7

Example 6

(21) The tests were conducted as for Example 1, and Example 6 illustrates test results of EF shielding efficiency tests depending on frequency for a shield with a matrix in the form of a polyethylene foil (PE) with calcium carbonate (CaCO.sub.3) and impregnated with an aqueous solution of MgCl.sub.2 with various modifiers. Table 6 shows the shielding efficiency SE of an electric field of various frequencies determined by SE=(E.sub.0E.sub.e)/E.sub.0 as a percentage (where E.sub.0 is the electric field strength in front of the screen and E.sub.e is the electric field strength behind the screen) for a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO.sub.3), the matrix impregnated with an aqueous solution of MgCl.sub.2 with various modifiers (specified percentage concentrations of additives are in wt percentage).

(22) TABLE-US-00006 TABLE 6 2 5 10 20 50 100 200 400 No. matrix (PE + CaCO.sub.3) kHz kHz kHz kHz kHz kHz kHz kHz 1 2.2% MgCl.sub.2 Aqueous 24.7 8.8 4.4 2.9 2.4 2.4 1.9 2.9 solution (aq. s.) 2 2.2% MgCl.sub.2 + 0.6% empilan 81.8 63.6 42.5 28.0 10.7 7.3 6.6 8.6 2502 detergent 3 2.2% MgCl.sub.2 + 0.6% elfacoze 73.3 56.3 41.1 26.7 15.4 10.8 8.1 7.2 200 detergent 4 2.2% MgCl.sub.2 + 0.6% emulgin 72.9 62.6 46.6 29.5 13.6 6.4 4.5 3.7 5 2.2% MgCl.sub.2 + 0.6% PEG 22 74.3 58.4 43.7 29.3 16.8 11.9 9.3 8.0

(23) In summary, it can be stated that it is possible to obtain EF shields of high efficiency in a broad range of field frequencies. It is very effective to use a mixture of an aqueous solution of MgCl.sub.2 with a styrene-acrylic dispersion, which has to be added in an amount of 90% (Table 3), and a silicone emulsion, where even the addition of a fraction of a percent is active (Table 4). Shielding efficiency and frequency range is increased by the addition of modifiers, e.g. a few to a few dozen percent of bentonite, sodium aluminum silicate, titanium white, lime powder, dolomite powder and talc.

(24) Subsequently, as can be seen in Examples 1-7, the optimum concentrations of these additives when an aqueous solution of MgCl.sub.2 is used depend both on the matrix type and the type of polymer dispersion.

Example 7

(25) Loose construction materials (increasing shielding range) were added to powdered hexahydrated magnesium chloride in the ratios given in Table 7. The following materials were used: synthetic gypsum, natural gypsum, cement, and slaked lime, and comminuted to obtain a homogenous powder mixture. Water was added to the mixture to obtain a suitable consistency and the mixture was used to coat a nonwoven polypropylene matrix of 25 g/m.sup.2 basic weight. After drying, an EF shield was obtained and shielding efficiency measurements were carried out in the frequency range of 2 kHz-400 kHz with the results given in Table 7 illustrating the shielding efficiency SE of an electric field of various frequencies determined by SE=(E.sub.0E.sub.e)/E.sub.0 as a percentage (where E.sub.0 is the electric field strength in front of the screen and E.sub.e is the electric field strength behind the screen) for a shield prepared according to the above description (specified percentage concentrations of additives are in wt percentage).

(26) TABLE-US-00007 TABLE 7 2 5 10 20 50 100 200 400 No. Matrix: nonwoven kHz kHz kHz kHz kHz kHz kHz kHz 1 2.2% MgCl.sub.2 Aqueous 84.4 68.7 54.8 40.5 25.0 14.1 8.1 5.3 solution (aq. s.) 2 aq.s. 50% synth. gypsum - 42.0 28.4 18.0 9.0 6.2 3.8 1.6 1.5 control 3 2.2% MgCl.sub.2 aq. s. + 0.1% 95.8 93.6 89.5 81.6 63.6 42.4 24.3 13.0 synth. gypsum 4 2.2% MgCl.sub.2 aq. s. + 5% 97.2 96.2 94.5 89.2 78.5 62.9 40.1 24.8 synth. gypsum 5 2.2% MgCl.sub.2 aq. s. + 50% 97.8 97.6 96.8 95.0 89.4 80.8 70.0 58.5 synth. gypsum 6 2.2%MgCl.sub.2 aq. s. + 70% 98.0 97.7 97.1 95.2 90.5 83.0 70.2 56.6 synth. gypsum 7 nat. gypsum - control 41.4 27.0 17.0 8.7 6.7 4.6 2.8 3.6 8 2.2% MgCl.sub.2 aq. s. + 0.1% nat. 96.9 95.8 93.2 88.1 73.7 55.6 35.0 18.0 gypsum 9 2.2% MgCl.sub.2 aq. s. + 5% nat. 97.1 96.4 94.9 90.4 80.5 65.4 44.7 27.8 gypsum 10 2.2% MgCl.sub.2 aq. s. + 50% nat. 96.8 96.9 96.8 96.3 94.1 89.8 83.2 74.9 gypsum 11 2.2% MgCl.sub.2 aq. s. + 70% nat. 96.9 96.8 96.2 94.2 89.0 80.1 64.1 48.8 gypsum 12 50% cement - control 2.8 1.3 0.6 0.2 0.1 0.3 0.2 0.6 13 2.2% MgCl.sub.2 aq. s. + 0.1% 96.8 95.6 93.1 88.4 75.6 58.9 38.8 23.6 cement 14 2.2% MgCl.sub.2 aq. s. + 5% 97.0 96.4 94.9 90.8 80.9 66.2 46.1 30.6 cement 15 2.2% MgCl.sub.2 aq. s. + 10% 97.0 96.8 96.1 94.0 87.6 77.0 62.2 48.9 cement 16 2.2% MgCl.sub.2 aq. s. + 30% 96.4 94.4 90.8 82.2 65.5 46.2 24.1 11.6 cement 17 2.2% MgCl.sub.2 aq. s. + 50% 82.1 63.1 47.4 32.3 16.5 7.2 1.3 0.2 cement 18 2.2% MgCl.sub.2 aq. s. + 70% 55.0 37.5 26.3 11.7 4.6 1.2 0.9 0.1 cement 19 2.2% MgCl.sub.2 aq. s. + 0.1% 83.5 71.0 58.4 41.9 25.3 15.8 9.2 6.6 Ca(OH)2 20 2.2% MgCl.sub.2 aq. s. + 0.6% 93.8 86.8 77.1 60.9 38.9 24.1 13.9 9.9 Ca(OH)2 21 2.2% MgCl.sub.2 aq. s. + 5% 95.9 95.5 94.8 92.5 84.9 72.4 54.2 42.1 Ca(OH)2

Example 8

(27) An impregnating solution of a mixture of an aqueous 2.2% MgCl.sub.2 solution with a 20% PVA dispersion and a 0.3% addition of bentonite was applied to commercially available construction materials in the form of:

(28) a) plasterboard,

(29) b) gypsum plaster wall,

(30) c) OSB board.

(31) The measured shielding efficiency for impregnated and dried boards is specified in Table 8, showing the decrease in electric field strength at the 50 Hz frequency due to the commercially available construction boards both before and after impregnation with a 2.2% MgCl.sub.2 mixture of an aqueous solution with a 20% PVA dispersion and a 0.3% addition of bentonite.

(32) TABLE-US-00008 TABLE 8 Gypsum Plasterboard plaster wall OSB board V/m V/m V/m Electric field strength 150 150 150 (control) Electric field strength after 137 139 145 shielding with board Electric field strength after 4 3 6 shielding with board painted once with shielding liquid Electric field strength after 1 2 3 shielding with board painted twice with shielding liquid

Example 9

(33) A foil-shield developed for protecting large surfaces (large devices, places of sleep) against low-frequency EF (up to approx. 20 kHz), produced on a production line. A polypropylene nonwoven of 25 g/m.sup.2 basic weight was unwound continuously from a horizontally placed bale, dragged through a bath containing the impregnating solution at room temperature, then pressed using a mangle and dried at 95 C. (for 0.5 min at a distance of 5 m) and wound on a roll. The bath contained a mixture of a 2.2% aqueous MgCl.sub.2 solution with a 20% PVA dispersion with the addition of 0.5% of bentonite and 0.1% of silica. The basic weight of the modified nonwoven increased by 30% in comparison with the basic weight of the non-modified nonwoven. Subsequently, the nonwoven was subjected to another treatment involving hot drenching on both sides with a polyethylene film. Such a screen-foil is impermeable to water and can be used as roof insulation, under floors and in walls. Dielectric measurements (FIG. 2) show that the obtained screen-foil exhibits dielectric losses (tan >1) in the low frequency range from 10.sup.2 Hz to 10.sup.7 Hz. Dependence of shielding efficiency on frequency for this screen is presented by the curve with data points in FIG. 3.

Example 10

(34) A shielding laminate was developed for protecting large surfaces against low-frequency EF (up to approx. 20 kHz). A mixture was formulated of 2.2% aqueous MgCl.sub.2 solution, a 20% PVA dispersion and 30% acrylic glue with the addition of 0.5% of bentonite and 0.1% of silica. The glue was used to join two layers of foil and, after drying at ambient temperature for approx. one week, an EF shielding laminate was obtained. The foil layers were made of vapour-permeable polyethylene foils with calcium carbonate inclusions. The amount of glue used was 16 g per 1 m.sup.2 of the foil. The dependence of EF shielding efficiency for such a laminate on frequency is presented by the curve with data points in FIG. 3.

Example 11

(35) A shielding floor underlay was developed to protect large surfaces against low-frequency EF (up to approx. 20 kHz), using a mixture of a 2.2% aqueous MgCl.sub.2 solution, a 20% PVA dispersion and 3% of acrylic glue with the addition of 0.5% of bentonite, 0.1% of silica, and 0.3% of kaolin. The glue was sprayed on XPS floor underlays and dried at 60 C. with ventilation. The amount of glue used was 5 g per 1 m.sup.2 of the underlay. The obtained material absorbs the electrical component of EMF, which is shown by the curve with data points in FIG. 3.

Example 12

(36) Shielding paint was produced using a mixture of a 2.2% aqueous MgCl.sub.2 solution, a 20% PVA dispersion and 0.4% bentonite, 2% kaolin, 0.1% of silica, and 0.5% of surface active agents. Primer paint (16 g/m.sup.2) intended for painting walls was applied with a paint roller on porous foil made of polyethylene with calcium carbonate inclusions that simulated a wall. After drying the foil painted with the primer shields low-frequency EF, as shown in Table 9 presenting the shielding efficiency SE of an electric field of various frequencies determined by SE=(E.sub.0E.sub.e)/E.sub.0 as a percentage (where E.sub.0 is the electric field strength in front of the screen and E.sub.e is the electric field strength behind the screen) for a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO.sub.3) painted with the shielding primer.

(37) TABLE-US-00009 TABLE 9 50 2 5 10 20 50 100 200 400 No. matrix (PE + CaCO.sub.3) Hz kHz kHz kHz kHz kHz kHz kHz kHz 1 Shielding primer 98.9 97.1 95.3 92.2 85.8 67.2 49.1 27.7 12.0

Example 13

(38) A gel high-frequency EMF screen was developed in order to shield equipment for nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR). The screen uses an encapsulated airtight gel produced on an aqueous base using 7% silica, 5% NH.sub.4Cl, 5% MgCl.sub.2 and 1% aluminum-sodium silicate. FIG. 4 presents the frequency characteristics of the attenuation efficiency of the gel placed between two poly(vinyl chloride) (PCV) foils, between which a nonwoven was placed to maintain a fixed screen thickness. The thickness of the gel layer was 1 mm. FIG. 5 presents the shielding efficiency at a frequency of 27 MHz for the same gel shield.

Example 14

(39) A gel high-frequency EMF screen was developed in order to shield equipment for nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR). The screen uses an encapsulated airtight gel produced on an aqueous base using gellan, silica, ammonium chloride, and magnesium chloride. FIG. 6 presents the frequency characteristics of the SE of the gel with additives placed between the poly(vinyl chloride) foil, between which a nonwoven was placed to maintain a fixed screen thickness. The thickness of the gel layer was 1 mm.

(40) Tables 10 and 11 present a comparison of the EF shielding efficiency by a screen using the same matrix with different fillers. Table 10 compares the 50 Hz EF shielding efficiency of a screen using a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO.sub.3) and impregnated with various impregnating solutions, while Table 11 presents the shielding efficiency of a polypropylene nonwoven impregnated with an aqueous MgCl.sub.2 solution with various modifiers in percentage.

(41) TABLE-US-00010 TABLE 10 styr.- acrylic silicone acryl PVA without dispersion dispersion dispersion dispersion polymer no. Matrix (PE + CaCO.sub.3) [dB] [dB] [dB] [dB] [dB] 1 2.2% MgCl.sub.2 Aqueous x x x x 10.4 solution (aq. s.) 2 2.2% MgCl.sub.2 aq. s. + 0.1% 4.4 53.7 5.3 14.7 x polym. disp. 3 2.2% MgCl.sub.2 aq. s. + 20% polym. 6.0 46.3 5.5 42.4 x disp. 4 2.2% MgCl.sub.2 aq. s. + 95.4% 4.5 6.7 19.6 16.5 x polym. disp. 5 no. 3 + 0.3% bentonite 9.0 9.6 10.7 49.2 24.0 6 no. 3 + 5% bentonite 11.0 9.2 39.7 49.2 44.1 7 no. 3 + 40% bentonite 14.1 17.0 33.1 25.3 47.7 8 no. 3 + 0.3% sod.-alum. silicate 9.0 9.8 11.7 51.2 16.0 9 no. 3 + 5% sod.-alum. silicate 8.2 24.2 15.7 59.7 20.1 10 no. 3 + 20% sod.-alum. silicate 24.3 15.6 17.3 34.3 20.5 11 no. 3 + 0.3% kaolin 7.4 8.8 12.0 49.2 21.7 12 no. 3 + 5% kaolin 26.7 4.9 10.7 49.2 45.2 13 no. 3 + 20% kaolin 57.2 53.7 42.4 47.7 46.3 14 no. 3 + 0.3% titanium white 6.5 9.2 8.4 49.2 17.8 15 no. 3 + 20% titanium white 18.9 6.8 53.7 51.2 45.2 16 no. 3 + 40% titanium white 47.7 53.7 53.7 53.7 42.4 17 no. 3 + 0.1% silica 7.6 5.3 12.2 53.7 21.7 18 no. 3 + 5% silica 49.2 9.3 59.7 57.2 31.2 19 no. 3 + 10% silica 59.7 35.3 47.7 44.1 32.9 20 no. 3 + 0.3% synth. lime powder 8.9 7.9 10.8 57.2 19.3 21 no. 3 + 5% synth. lime powder 12.1 8.6 7.3 51.2 42.4 22 no. 3 + 20% synth. lime powder 25.7 38.1 29.2 53.7 44.1 23 no. 3 + 0.3% nat. lime powder 9.1 10.0 14.8 49.2 21.1 24 no. 3 + 5% nat. lime powder 10.8 14.8 11.2 49.2 35.3 25 no. 3 + 20% nat. lime powder 16.9 27.4 15.9 47.7 46.3 26 no. 3 + 0.3% dolomite powder 8.6 8.5 11.9 63.2 17.8 27 no. 3 + 5% dolomite powder 8.6 10.6 11.8 49.2 16.4 28 no. 3 + 20% dolomite powder 39.1 28.4 34.3 49.2 40.3 29 no. 3 + 0.3% talc 8.0 8.0 9.9 51.2 16.9 30 no. 3 + 5% talc 8.5 7.9 11.5 51.2 42.4 31 no. 3 + 20% talc 17.7 29.6 25.4 57.2 44.1 32 no. 3 + 0.01% defoamer 7.6 8.2 11.8 48.4 19.7 33 no. 3 + 0.6% defoamer 7.8 9.5 14.5 46.3 18.6 34 no. 3 + 5% defoamer 7.0 7.0 10.6 41.6 17.7 35 no. 3 + 0.01% dispersant 5.6 7.8 11.3 49.2 21.2 36 no. 3 + 0.6% dispersant 7.9 7.1 9.1 53.7 16.2 37 no. 3 + 5% dispersant 6.0 6.1 11.2 43.2 16.5 38 no. 3 + 0.1% poly(vinyl alcohol) x x x 53.7 x 39 no. 3 + 0.3% poly(vinyl alcohol) x x x 46.3 x 40 no. 3 + 5% poly (vinyl alcohol) x x x 47.7 x 41 no. 3 + 0.1% x x x 46.3 x carboxymethylcellulose 42 no. 3 + 0.3% x x x 53.7 x carboxymethylcellulose 43 no. 3 + 1% x x x 47.7 x carboxymethylcellulose 44 no. 3 + 0.01% BIOCIDE x x x 51.2 x 45 no. 3 + 0.1% BIOCIDE x x x 53.7 x 46 no. 3 + 0.6% BIOCIDE x x x 45.2 x 47 0.1% MgCl.sub.2 aqueous solution x x x x 0.6 48 MgCl.sub.2 saturated aqueous x x x x 8.3 solution

(42) TABLE-US-00011 TABLE 11 2 5 10 20 50 100 200 400 No. PP nonwoven matrix kHz kHz kHz kHz kHz kHz kHz kHz 1 2.2% MgCl.sub.2 aqueous 84.4 68.7 54.8 40.5 25.0 14.1 8.1 5.3 solution (aq. s.) 2 2.2% MgCl.sub.2 aq. s. + 0.6% 93.9 87.0 77.2 61.8 42.2 26.7 14.8 9.3 propylene glycol 3 2.2% MgCl.sub.2 + 0.6% Euxyl 96.5 93.6 88.5 77.9 58.1 39.1 20.3 9.3 K120 preservative 4 2.2% MgCl.sub.2 + 0.6% Euxyl 95.4 92.1 86.4 77.1 57.4 38.5 23.9 14.0 K702 preservative 5 2.2% MgCl.sub.2 + 0.6% Euxyl 96.5 93.4 93.5 78.9 59.0 41.9 26.4 15.0 9010 preservative 6 2.2% MgCl.sub.2 + 0.6% 94.5 87.6 77.2 62.5 40.9 23.2 9.9 3.4 Mystic Zen fragrance composition