A 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

The object of the invention is a composition for impregnating other materials, rendering them able to shield alternating electromagnetic fields in the range from low frequencies up to radio frequencies, containing an aqueous solution of salt that may form hydrates or a combination of salts, of which at least one forms a hydrate, characterised in that it contains an acrylic and/or styrene-acrylic dispersion and/or silicone emulsion and/or enhancing additives selected from a group containing surfactants and/or aluminosilicates and silicates and/or soluble and insoluble calcium compounds, metal and metalloid oxides, while an alternating field is shielded at least in range from 10.sup.−2 Hz to 10.sup.6 Hz and its application for coating/impregnating fibrous and/or porous matrix and materials containing the thereof.

Claims

1. A composition or impregnating materials, rendering them able to shield alternating electromagnetic fields and containing an aqueous solution of salt that may form hydrates or a combination of salts, of which at least one forms a hydrate characterised in that it contains acrylic and/or styrene-acrylic dispersion and/or silicone emulsion and/or enhancing additives selected from a group containing surfactants and/or aluminosilicates and silicates and/or soluble and insoluble calcium compounds, metal and metalloid oxides, while the alternating field is shielded at least in the range 10.sup.−2 Hz to 10.sup.6 Hz.

2. The composition of claim 1, characterised in that surface active agents are compounds selected from a group containing detergents, surfactants, emulsifiers, amphiphiles, preferably defoamers, dispersants, and glycols.

3. The composition of claim 1, characterised in that aluminosilicate and silicates are selected compounds from a group containing bentonite, kaolin, and talc.

4. The composition of claim 1, characterised in that insoluble calcium compounds are selected compounds from a group containing powdered limestone and dolomite.

5. The composition of claim 1, characterised in that it contains compounds selected from a group containing gypsum, calcium hydroxide, and Portland cement.

6. The composition of claim 1, characterised in that it contains resins, preferably alkyd resin in organic solvent, and epoxide resin in a solid state or solution, phenol formaldehyde resin in ethanol, or silicone resin in solution or suspension.

7. The composition of claim 1, characterised in that for airtight gel shields shielding occurs up to 3 GHz.

8. Use of the composition defined in claims 1 to 6 for coating/impregnating fibrous and/or porous matrix, which after drying obtain EMF shielding properties, preferable for coating or modifying construction, furniture, textile and clothing materials.

9. The use of claim 8, characterised in that construction materials are primers, plaster/paint primers, paints, plastering mortars, laminates used in constructions including: roof membranes, vapour barrier laminates with particular application for roofs and other applications, vapour-permeable laminates, foils coated with shielding solution, and textiles with shielding properties.

10. Electric field shielding construction, furniture, and textile or clothing material characterised in that it contains the composition defined in claim 1.

Description

[0015] The Examples of the invention are presented in the figures, where

[0016] FIG. 1 presents the dependence of the real and imaginary part of permittivity (∈′, ∈″) and dielectric losses (tan δ) on frequency for a foil-screen produced on a production line,

[0017] FIG. 2 presents the dependency of shielding efficiency on frequency for various screens,

[0018] FIG. 3 presents a comparison of shielding efficiency dependence on frequency for a screen in the form of 12 μm thick aluminium 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,

[0019] FIG. 4 presents a comparison of dependence of shielding efficiency on the electric and magnetic component for a gel screen at a frequency of 27 MHz,

[0020] FIG. 5 presents a comparison of 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 containing additionally gel gellan,

[0021] FIG. 6 presents a comparison of dependence of shielding efficiency SE of electric field determined as SE=(E.sub.0−E.sub.e)/E.sub.0 as a percentage (E.sub.0 is the electric field strength before the screen, E.sub.e is the electric field strength behind the screen) on frequency 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), while

[0022] FIG. 7 presents a comparison of shielding of the invention shown in patent application PL387274 and composition according to the presented invention with additions for low humidity environments.

EXAMPLE 1

[0023] In order to illustrate the advantages of the invention, its performance was compared with a prior known solution. As a typical prior art for the presented invention, the invention shown in patent application PL387274 is shown below, 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 the 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 humidity—in 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. C&C generator FG-220C was used as the source of the alternating electric field. Measurement results from 10.sup.1 to 5×10.sup.4 Hz are presented in the illustration labelled state-of-the-art illustrating the dependence on the frequency of 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. 7 presents a comparison of the shielding of the invention shown in patent application PL387274 and the composition according to the presented 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 25% to 37%.

[0024] Examples of the invention are presented in the Tables and in the illustration with figures presenting the measurement results of shielding efficiency. The Table and illustration present the measurement results of shielding efficiency (SE) SE=(E.sub.0−E.sub.e)/E.sub.0 (E.sub.0—electric field strength in front of the screen, E.sub.e—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 presents 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 PVA dispersion and a mixture of an aqueous solution MgCl.sub.2 with PVA dispersion and various modifiers. The first four results with figure labelled prior art 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 optimum concentration. The further positions of Table 1 show the effect of modifiers: bentonite, sodium aluminosilicate, kaolin, titanium white, silica, talc, lime powder, dolomite powder, defoamer (emulsion of silicone oil, dispersant (sodium polyacrylate), poly(vinyl alcohol), carboxymethylcellulose and biocide (Kathon 886). Table 1 presents shielding efficiency SE of an electric field determined as SE=(E.sub.0−E.sub.e)/E.sub.0 as a percentage (E.sub.0 is the electric field strength in front of the screen, 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) impregnated with a mixture of an aqueous solution of MgCl.sub.2 with PVA dispersion and various modifiers (specified percentage concentrations of additives are in wt percentage).

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

[0025] The tests carried out were as for Example 1, and Example 2 illustrates tests of EF shielding efficiency depending on frequency for a shield in form of a polyethylene foil matrix with calcium carbonate (CaCO.sub.3) impregnated with a mixture of an aqueous solution of MgCl.sub.2 with acrylic dispersion and various modifiers (Table 2—shielding efficiency SE of electric field determined as SE=(E.sub.0−E.sub.e)/E.sub.0 as a percentage (E.sub.0 is the electric field strength in front of the screen, 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) impregnated with a mixture of an aqueous solution of MgCl.sub.2 with acrylic dispersion and various modifiers (specified percentage concentrations of additives are in wt percentage).

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

[0026] The tests carried out were as for Example 1, and Example 3 illustrates tests of EF shielding efficiency depending on frequency for a shield in form of a polyethylene foil matrix with calcium carbonate (CaCO.sub.3) impregnated with a mixture of an aqueous solution of MgCl.sub.2 with styrene-acrylic dispersion and various modifiers (Table 3—shielding efficiency SE of electric field determined as SE=(E.sub.0−E.sub.e)/E.sub.0 as a percentage (E.sub.0 is the electric field strength in front of the screen, 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) 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).

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

[0027] The tests carried out were as for Example 1, and Example 4 illustrates tests of EF shielding efficiency depending on frequency for a shield in form of a polyethylene foil matrix with calcium carbonate (CaCO.sub.3) impregnated with a mixture of an aqueous solution of MgCl.sub.2 with a silicone emulsion and various modifiers (Table 4—shielding efficiency SE of an electric field determined as SE=(E.sub.0−E.sub.e)/E.sub.0 as a percentage (E.sub.0 is the electric field strength in front of the screen, 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) impregnated with a mixture of an aqueous solution of MgCl.sub.2 with silicone emulsion and various modifiers (specified percentage concentrations of additives are in wt percentage).

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

[0028] The tests carried out were as for Example 1, and Example 5 illustrates tests of EF shielding efficiency depending on frequency for a shield in form of a polyethylene foil matrix with calcium carbonate (CaCO.sub.3) impregnated with an aqueous solution of MgCl.sub.2 and various modifiers (Table 5—shielding efficiency SE of an electric field determined as SE=(E.sub.0−E.sub.e)/E.sub.0 as % (E.sub.0 is the electric field strength in front of the screen, 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) impregnated with an aqueous solution of MgCl.sub.2 and various modifiers (specified percentage concentrations of additives are in wt percentage).

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

[0029] The tests were conducted as for Example 1, and Example 6 illustrated results of EF shielding efficiency tests depending on the frequency for a shield with a matrix in the form of a polyethylene foil (PE) with calcium carbonate (CaCO.sub.3) impregnated with an aqueous solution of MgCl.sub.2 with various modifiers (Table 6). Shielding efficiency SE of an electric field of various frequencies determined as SE=(E.sub.0−E.sub.e)/E.sub.0 as a percentage (E.sub.0 is the electric field strength in front of the screen, 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) impregnated with an aqueous solution of MgCl.sub.2 with various modifiers (specified percentage concentrations of additives are in wt percentage).

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

[0030] 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 styrene-acrylic dispersion, which has to be added in amount of: ˜90% (Table 3) and a silicone emulsion, where even the addition of fraction of a percent is active (Table 4). Shielding efficiency and frequency range is increased by addition of: modifiers, e.g. a few to few dozen percent of bentonite, sodium aluminium silicate, titanium white, lime and dolomite powder and talc.

[0031] 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

[0032] Loose construction materials (increasing shielding range) were added to powdered hexahydrated magnesium chloride in the ratio 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 as SE=(E.sub.0−E.sub.e)/E.sub.0 as % (E.sub.0 is the electric field strength in front of the screen, 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).

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

[0033] An impregnating solution of the following composition: mixture of an aqueous 2.2% MgCl.sub.2 solution with 20% PVA dispersion and 0.3% addition of bentonite was applied to commercially available construction materials in the form of: [0034] a) plasterboard, [0035] b) gypsum plaster wall, [0036] c) OSB board.
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 materials in the form of boards, before and after impregnation with a 2.2% MgCl.sub.2 mixture of an aqueous solution with 20% PVA dispersion and the addition of 0.3% bentonite.

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

[0037] 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, than 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 subject 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. 1) show that the obtained screen-foil exhibits dielectric losses (tan δ>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. 2.

EXAMPLE 10

[0038] A shielding laminate was developed for protecting large surfaces against low-frequency EF (up to approx. 20 kHz). Using the following substances: a mixture of 2.2% aqueous MgCl.sub.2 solution, 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 foils 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. Dependence of EF shielding efficiency for such a laminate on frequency is presented by the curve in FIG. 2, with data points.

EXAMPLE 11

[0039] Shielding floor underlay was developed to protect large surfaces against low-frequency EF (up to approx. 20 kHz), using the following substances: a mixture of a 2.2% aqueous MgCl.sub.2 solution, 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. 2.

EXAMPLE 12

[0040] Shielding paint was produced using the following substances: a mixture of a 2.2% aqueous MgCl.sub.2 solution, 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 painting roll 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 as SE=(E.sub.0−E.sub.e)/E.sub.0 as a percentage (E.sub.0 is the electric field strength in front of the screen, 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 shielding primer.

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

[0041] 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% of aluminium-sodium silicate. FIG. 3 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 the fixed screen thickness. The thickness of the gel layer was 1 mm FIG. 3 presents the shielding efficiency at a frequency of 27 MHz for the same gel shield.

EXAMPLE 14

[0042] 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. 5 presents the frequency characteristics of 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.

[0043] Table 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 the screen using a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO.sub.3) 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.

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

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