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

Information

  • Patent Application
  • 20170349765
  • Publication Number
    20170349765
  • Date Filed
    November 24, 2015
    10 years ago
  • Date Published
    December 07, 2017
    8 years ago
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 10−2 Hz to 106 Hz and its application for coating/impregnating fibrous and/or porous matrix and materials containing the thereof.
Description

The present invention relates to a composition for impregnating other materials, thus making them capable of shielding against the effects of alternating electromagnetic fields, including its use in coating and modifying construction materials, furniture, textiles, clothing and other materials. The invention can be applied in the construction industry, for household goods, for coating the structural elements of buildings and for shielding electrical and electronic devices.


The technological development of electromechanical, electronic, teletechnical and IT devices, as well as their rapidly increasing application, requires us to analyse the impact of electric (EF), magnetic (MF) and electromagnetic fields (EMF) on human health. The following organisations are involved in work on the problem: WHO (World Health Organization), European Commission: HEALTH & CONSUMER PROTECTION, International Commission on Non-Ionizing Radiation Protection and IEEE (Institute of Electrical and Electronics Engineers). The analysis of the health condition in the USA during the rapid electrification process in the 1940s indicates that electromagnetic radiation contributes more to civilization diseases than the actual change of lifestyle [Medical Hypotheses 74(2010)337]. As we cannot give up using electrical devices, the only solution is to shield them. Classical materials for EF shielding are single-phase materials of high electric conductivity (metals, carbon, conductive polymers and their combinations) based on the Faraday cage effect. Metal foils and grids placed, inside a polymer or glass, conductive polymers and materials made of cotton and polyester with woven-in micron diameter silver or stainless steel wires are applied as EF shields [IEEE Trans. Electromagnetic Compatibility 30(1988)187; ibid 30(1988)282].


These types of solutions are disclosed in U.S. Pat. No. 6,028,266—Low frequency MF shield and U.S. Pat. No. 6,320,123—EMF shielding, as well as for electric cable shielding. A novel solution is the application of multi-phase materials to form composites for EMF shielding, because when tailoring the properties of the component phases, their weight/volume ratio and connectivity, one can obtain materials with properties suited to the requirements of the intended application [J. Mater. Sci. 44(2009)3917; Progress Mater. Sci. 59(2013)183].


Many patented solutions are related to EMF shielding composites in the GHz frequency range. This solution is disclosed, among others, in the following patents: U.S. Pat. No. 3,599,210, EP 0312333B1, FR 2695760A1, EP0420513B1, U.S. Pat. No. 5,661,484, and JP10013081. There are other inventions for EMF shielding composites having a wide range from Hz to GHz, such as in international patent application WO2002/40799A1, U.S. Pat. No. 6,337,125B1, international patent application WO2003031722A1 and polish patent PL203956. A wide EMF shielding range (from Hz to GHz) was given in international patent application WO 2002/40799A1, where the shielding material used a composite based on a matrix filed with cements, plaster or gypsum combined with various ashes, slag, micro-silica and limestone (CaCO3 with admixtures) and components reflecting/absorbing electromagnetic radiation, such as exfoliated graphite, electrode graphite, graphite flakes, carbon fibres, soot, ferrites and carborundum (SiC). The shielding material contains 1-6 layers of metal grid and 0.5-60% w/w of iron filings. U.S. Pat. No. 6,337,125B1 presents devices and methods for the production of composites absorbing electromagnetic radiation that allows for increased absorption rate and are thinner and/or lighter than those previously used. These are a combination of synthetic dielectric materials either with a synthetic magnetic material or another material with a high magnetic losses such that the dielectric permittivity and magnetic susceptibility are matched in the desired frequency range. The frequency absorption band is from 10 MHz to 10 GHz.


International patent application WO2003/031722A1 shows a composite composed of a suitably selected layer to reflect electromagnetic waves and an absorbing layer containing conductive fibres, e.g. carbon fibres of lengths chosen to suit the band of absorbed electromagnetic waves.


Polish patent PL203956B1 shows a material absorbing electromagnetic waves in a frequency band from a few kHz to ˜2 GHz as a nanocomposite composed of kaolinite stripes of relatively low permittivity and layers of organic polar molecules of high permittivity. The kaolinite packages are <1 nm thick, while a 0.2-2 nm layer of polar organic molecules is of imidazole. This is polar organic molecules intercalated with kaolinite.


Chinese patent application CN103755333 presents a composite composed of a matrix in the form of a silicone rubber foam filled with magnesium-barium-aluminium nanoferrite. In this case the radiation absorbent is nanoferrite; however the shielding frequency of the patented composite is not specified.


Polish patent application PL387274 presents an aqueous solution for impregnating materials to shield against alternating electric fields with low-frequency characteristics. This involves a liquid containing a hydratable salt or salt mixture from the set MgCl2, Na3PO4, CuSO4 and other hydratable salts, while the weight ratio of salt or salt mixture with water is in the range 1:1 to 1:100, and with the optional addition of a polymer from a group used for applying finishes to textiles, especially poly(vinyl acetate). The Prior Art figure shown before the presented invention demonstrates the absorption of an electric field using a polyester material impregnated with an aqueous solution of MgCl2:H2O in the ratio 1:20 with the addition of a poly(vinyl acetate) dispersion.


Generally applied EMF shields in the low-frequency range using single-phase materials of high electric conductivity that are heavy, expensive and usually require grounding. Moreover, the majority of shields use multi-phase systems: composites to shield EMF in the microwave band or from few kHz to few GHz along with composites with a specific shielding properties in the Hz-GHz range that also contain metal meshes and iron filling (thus require grounding). The search continues for a material able to shield EMF starting from low frequencies, i.e. from 10−2 Hz, to radio frequencies, i.e. up to 106 Hz and higher, in the order of several GHz, without the need for grounding while remaining light and useable in various forms: foil, nonwoven, plaster, wall or wood, and could even shield at low relative humidities. Unexpectedly, all the above problems were solved by the presented invention.


The presented invention is a composition designed to impregnate other materials, thus rendering them able to shield against the effects of alternating electromagnetic field. It contains an aqueous solution of salt that may form hydrates or combinations of salts, of which at least one forms a hydrate, characterised by its content of 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 the alternating field is shielded at least in range from 10−2 Hz to 106 Hz. The composition, according to the invention, is preferably characterized by having surface active agents that are compounds selected from a group containing detergents, surfactants, emulsifiers, amphiphiles, preferable defoamers, dispersants, and glycols. The composition according to the invention is preferably characterized in that aluminosilicates and silicates are compounds selected from the group containing bentonite, kaolin, and talc. The composition according to the invention is preferably characterized in that insoluble calcium compounds are compounds selected from the group containing powdered limestone and dolomite. The composition according to the invention is preferably characterized by containing compounds selected from the group containing gypsum, calcium hydroxide, and Portland cement. The composition according to the invention is preferably characterized by containing resins, preferably alkyd resin in an organic solvent, and epoxide resin in a solid state or solution, phenol formaldehyde resin in ethanol, or silicone resin in solution or suspension. The compounds used that may form inorganic hydrates are: MgCl2 (MgClz.6H2O), CaCl2 [CaCl2.H2O, CaCl2.2H2O, CaCl2.6H2O], NaCO3 [NaCO3.H2O, NaCO3.7H2O, NaCO3.10H2O], LiCl [LiCl.H2O, LiCl.8H2O] and others. As polymer dispersions, acrylic dispersion, styrene-acrylic dispersion and silicone emulsion can be used. The invention can use as modifiers, surface active agents, i.e. defoamers as a silicone oil emulsion, dispersants such as sodium polyacrylate, anionic active emulsifiers and viscosity enhancers such as carboxymethylcellulose and poly(ethylene oxide). As modifiers also the following compounds can be used: basic magnesium silicate [Mg3Si4O10(OH)2-talc], basic aluminium silicate [Al2Si2O5(OH)4-kaolinite, the main component of kaolin] and aluminosilicates in form of bentonite, as well as calcium compounds: lime powder [>90% CaCO3], dolomite powder [(Ca, Mg)(CO3)2], gypsum [CaSO4.2H2O] and Portland cement [3CaO.SiO2 (50-65%), 2CaO.SiO2 (˜20%), 4CaO.Al2O3.Fe2O3 (˜10%) and 3CaO.Al2O3 (˜10%)]. It is preferable when the hydratable salt:water weight ratio is in the range from salt concentration in saturated solution to 1:1,000, polymer:water ratio is in the range from 1:1 to 1:2,000, weight ratio of surface active agents:water is in the range from 1:20 up to 1:10,000, while inorganic modifiers:water weight ratio is in the range 1:0.5 up to 1,000. Equally preferable for airtight gel shields, shielding occurs up to 3 GHz.


Another object of the invention is the use of the composition defined in the first object for coating/impregnating fibrous and/or porous matrices, which after drying obtain EMF shielding properties, preferable for coating or modifying constructional, furniture, textile and clothing materials. Preferable construction materials according to the invention 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 the shielding solution, and textiles with shielding properties. The invention used as fibrous materials cellulose, viscose, polyester and other polymer nonwoven, spun and knitted fabrics, while as porous materials the following are used: cement, different bricks, plaster, gypsum board, plasterboard, cement board, OSB and similar materials of different commercial names, wood, laminates and various and vapour-permeable and vapour barrier roof membranes. Materials impregnated with composition such as nonwovens, spun or knitted materials or construction material such as cement, plaster, gypsum board/plasterboard/cement board, ceramic materials, bricks, silicate blocks or wood form composite matrix, whose EMF absorbing materials after drying are bound with water in form of micro- and nanodroplets entrapped on the surface of pores/nanopores and modifier grains in form of hydration water (connected with salts forming hydrates) and water absorbed in bulk (bentonite) as well as dispersed polymer particles and introduced modifier particles.


The third object of the invention is electrical field shielding for construction, furniture, textile or clothing material characterised in that it contains the component material defined in the first object of the invention.


An essential feature of the invention is the development of the shielding composition for impregnation of fibrous and/or porous materials intended for shielding electromagnetic fields in the low frequency band of 10−2 Hz up to radio frequencies, i.e. 106 Hz. The composition is a mixture of: an aqueous solution of one or more salts able to form hydrates, a polymer dispersion (acrylic or styrene-acrylic dispersion or silicone emulsion) and/or modifiers (surface active agents and/or silicates and aluminosilicates and/or water soluble and insoluble calcium compounds). Materials containing the composition according to the invention such as nonwoven, spun or knitted materials and/or construction materials such as cements, gypsum board/plasterboard/cement board, ceramic materials/bricks, silicate blocks and/or wood are composite matrices of statistic topology, which, after drying, shields electromagnetic radiation. The shielding properties of this composite are related to dielectric absorption arising from the dielectric losses of all composite components and with the Maxwell-Wagner polarization occurring in this composite related to the difference between the permittivity of the matrix and fillers as well as of the entrapped water and modifiers. By changing the type and topology of the matrix as well as the type and concentration of the hydratable salt, concentration of polymer dispersion, type and concentration of modifiers, it is possible to adjust the shielding frequency band to suit the requirements of the application.


It is preferable for the matrix to have pores and/or slits and/or capillaries. Preferably a composite matrix belonging to the group containing textiles, knitted materials, nonwovens, ceramics, wood, plastics, construction materials and various systems thereof. EMF shielding composites were produced and electric field shielding tests were carried out for different porous matrices such as ceramics, nonwoven and similar materials impregnated with impregnating solutions of various compositions. The effect of matrix structure and type (such as porosity, weight, hydrophilic properties) was studied, as well as the effect of temperature and humidity. Shields manufactured according to the invention can be used for the production of different types of screens to be used in construction, such as nonwoven roofing, roof membranes, bricks, ceramic tiles, cement, mortar and plaster, paint, primers, putty or can be applied directly to a building wall to protect living organisms and electronic devices against the effect of alternating EMF. Shielding materials can also be used directly e.g. for electrical outlets and electric cables. Another application of the impregnating solution is the production of whole-bed mats. Screens with a matrix made of nonwoven, spun or knitted materials can be used also for the production of clothing, bedsheets, quilts, tents, sleeping bags and foam pads. Protection of human health and electronic devices does not exhaust the uses of the present invention. The invention can be used for protecting rooms and buildings against electronic information leakage, etc.





The Examples of the invention are presented in the figures, where



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,



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



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 NH4Cl and MgCl2 with the addition of SiO2,



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,



FIG. 5 presents a comparison of dependence of shielding efficiency on frequency for a screen containing an aqueous solution of gel NH4Cl and MgCl2 with the addition of SiO2 and a screen containing additionally gel gellan,



FIG. 6 presents a comparison of dependence of shielding efficiency SE of electric field determined as SE=(E0−Ee)/E0 as a percentage (E0 is the electric field strength before the screen, Ee 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 (CaCO3) impregnated with various aqueous solutions of hydratable salts with the addition of bentonite (specified percentage concentration of additives are in wt percentage), while



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

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 MgCl2 solution at a temperature not exceeding 117° C. in order to obtain an EF shield. The solution was prepared in the weight ratio MgCl2.6H2O:H2O 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 101 to 5×104 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 MgCl2 with the addition of a 20% acrylic dispersion and 5% silica at a relative humidity in the range 25% to 37%.


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=(E0−Ee)/E0 (E0—electric field strength in front of the screen, Ee—electric field strength behind the screen) or shielding efficiency in dB. Different matrices were impregnated with 16 g/m2 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 10−2 to 107 Hz. Table 1 presents the increase of shielding efficiency of a model wall made of a matrix (PE+CaCO3) after impregnation with various impregnating solutions: an aqueous solution of MgCl2, a mixture of an aqueous solution of MgCl2 with PVA dispersion and a mixture of an aqueous solution MgCl2 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=(E0−Ee)/E0 as a percentage (E0 is the electric field strength in front of the screen, Ee is the electric field strength behind the screen) for a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO3) impregnated with a mixture of an aqueous solution of MgCl2 with PVA dispersion and various modifiers (specified percentage concentrations of additives are in wt percentage).


















TABLE 1







2
5
10
20
50
100
200
400


No.
matrix (PE + CaCO3) + fillers
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
























1
2.2% of MgCl2 aqueous
24.7
8.8
4.4
2.9
2.4
2.4
1.9
2.9



solution (aq. s.)


2
2.2% MgCl2 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% MgCl2 aq. s. + 20% PVA
76.6
62.1
42.1
23.6
15.3
11.9
9.2
7.7



dis.


4
2.2% MgCl2 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

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 (CaCO3) impregnated with a mixture of an aqueous solution of MgCl2 with acrylic dispersion and various modifiers (Table 2—shielding efficiency SE of electric field determined as SE=(E0−Ee)/E0 as a percentage (E0 is the electric field strength in front of the screen, Ee is the electric field strength behind the screen) for a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO3) impregnated with a mixture of an aqueous solution of MgCl2 with acrylic dispersion and various modifiers (specified percentage concentrations of additives are in wt percentage).


















TABLE 2







2
5
10
20
50
100
200
400


No.
matrix (PE + CaCO3)
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% MgCl2 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% MgCl2 aq. s. + 20% PVA
35.6
16.5
10.5
8.1
6.6
5.6
4.3
4.3



dis.


4
2.2% MgCl2 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

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 (CaCO3) impregnated with a mixture of an aqueous solution of MgCl2 with styrene-acrylic dispersion and various modifiers (Table 3—shielding efficiency SE of electric field determined as SE=(E0−Ee)/E0 as a percentage (E0 is the electric field strength in front of the screen, Ee is the electric field strength behind the screen) for a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO3) impregnated with a mixture of an aqueous solution of MgCl2 with styrene-acrylic dispersion and various modifiers (specified percentage concentrations of additives are in wt percentage).


















TABLE 3







2
5
10
20
50
100
200
400


No.
matrix (PE + CaCO3)
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% MgCl2 + 0.1% styr.-acr.
25.0
10.9
8.2
5.8
5.5
5.6
5.0
6.1



disp.


3
2.2% MgCl2 + 20% styr.-acr.
29.7
15.3
9.9
6.5
6.0
4.9
3.0
4.2



disp.


4
2.2% MgCl2 + 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

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 (CaCO3) impregnated with a mixture of an aqueous solution of MgCl2 with a silicone emulsion and various modifiers (Table 4—shielding efficiency SE of an electric field determined as SE=(E0−Ee)/E0 as a percentage (E0 is the electric field strength in front of the screen, Ee is the electric field strength behind the screen) for a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO3) impregnated with a mixture of an aqueous solution of MgCl2 with silicone emulsion and various modifiers (specified percentage concentrations of additives are in wt percentage).


















TABLE 4







2
5
10
20
50
100
200
400


No.
matrix (PE + CaCO3)
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% MgCl2 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% MgCl2 aq. s. + 20% sil.
94.2
92.3
88.4
81.3
65.3
49.2
26.9
14.4



emulsion


4
2.2% MgCl2 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% MgCl2 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% MgCl2 aq. s. + 20% tit.
38.1
20.3
12.7
8.5
7.7
5.7
4.2
4.2



white


7
2.2% MgCl2 aq. s. + 40% tit.
97.2
96.2
94.2
90.4
79.6
63.7
43.2
24.0



white









EXAMPLE 5

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 (CaCO3) impregnated with an aqueous solution of MgCl2 and various modifiers (Table 5—shielding efficiency SE of an electric field determined as SE=(E0−Ee)/E0 as % (E0 is the electric field strength in front of the screen, Ee is the electric field strength behind the screen) for a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO3) impregnated with an aqueous solution of MgCl2 and various modifiers (specified percentage concentrations of additives are in wt percentage).


















TABLE 5







2
5
10
20
50
100
200
400


No.
matrix (PE + CaCO3)
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
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

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 (CaCO3) impregnated with an aqueous solution of MgCl2 with various modifiers (Table 6). Shielding efficiency SE of an electric field of various frequencies determined as SE=(E0−Ee)/E0 as a percentage (E0 is the electric field strength in front of the screen, Ee is the electric field strength behind the screen) for a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO3) impregnated with an aqueous solution of MgCl2 with various modifiers (specified percentage concentrations of additives are in wt percentage).


















TABLE 6







2
5
10
20
50
100
200
400


No.
matrix (PE + CaCO3)
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% MgCl2 + 0.6% empilan
81.8
63.6
42.5
28.0
10.7
7.3
6.6
8.6



2502 detergent


3
2.2% MgCl2 + 0.6% elfacoze
73.3
56.3
41.1
26.7
15.4
10.8
8.1
7.2



200 detergent


4
2.2% MgCl2 + 0.6% emulgin
72.9
62.6
46.6
29.5
13.6
6.4
4.5
3.7


5
2.2% MgCl2 + 0.6% PEG 22
74.3
58.4
43.7
29.3
16.8
11.9
9.3
8.0









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 MgCl2 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.


Subsequently, as can be seen in Examples 1-7, the optimum concentrations of these additives when an aqueous solution of MgCl2 is used depend both on the matrix type and the type of polymer dispersion.


EXAMPLE 7

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/m2 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=(E0−Ee)/E0 as % (E0 is the electric field strength in front of the screen, Ee 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 7







2
5
10
20
50
100
200
400


No.
Matrix: nonwoven
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
























1
2.2% MgCl2 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% MgCl2 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% MgCl2 aq. s. + 5%
97.2
96.2
94.5
89.2
78.5
62.9
40.1
24.8



synth. gypsum


5
2.2% MgCl2 aq. s. + 50%
97.8
97.6
96.8
95.0
89.4
80.8
70.0
58.5



synth. gypsum


6
2.2%MgCl2 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% MgCl2 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% MgCl2 aq. s. + 5% nat.
97.1
96.4
94.9
90.4
80.5
65.4
44.7
27.8



gypsum


10
2.2% MgCl2 aq. s. + 50% nat.
96.8
96.9
96.8
96.3
94.1
89.8
83.2
74.9



gypsum


11
2.2% MgCl2 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% MgCl2 aq. s. + 0.1%
96.8
95.6
93.1
88.4
75.6
58.9
38.8
23.6



cement


14
2.2% MgCl2 aq. s. + 5%
97.0
96.4
94.9
90.8
80.9
66.2
46.1
30.6



cement


15
2.2% MgCl2 aq. s. + 10%
97.0
96.8
96.1
94.0
87.6
77.0
62.2
48.9



cement


16
2.2% MgCl2 aq. s. + 30%
96.4
94.4
90.8
82.2
65.5
46.2
24.1
11.6



cement


17
2.2% MgCl2 aq. s. + 50%
82.1
63.1
47.4
32.3
16.5
7.2
1.3
0.2



cement


18
2.2% MgCl2 aq. s. + 70%
55.0
37.5
26.3
11.7
4.6
1.2
0.9
0.1



cement


19
2.2% MgCl2 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% MgCl2 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% MgCl2 aq. s. + 5%
95.9
95.5
94.8
92.5
84.9
72.4
54.2
42.1



Ca(OH)2









EXAMPLE 8

An impregnating solution of the following composition: mixture of an aqueous 2.2% MgCl2 solution with 20% PVA dispersion and 0.3% addition of bentonite was applied to commercially available construction materials in the form of:

    • a) plasterboard,
    • b) gypsum plaster wall,
    • 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% MgCl2 mixture of an aqueous solution with 20% PVA dispersion and the addition of 0.3% bentonite.













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

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/m2 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 MgCl2 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 10−2 Hz to 107 Hz. Dependence of shielding efficiency on frequency for this screen is presented by the curve with data points in FIG. 2.


EXAMPLE 10

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 MgCl2 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 m2 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

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 MgCl2 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 m2 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

Shielding paint was produced using the following substances: a mixture of a 2.2% aqueous MgCl2 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/m2) 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=(E0−Ee)/E0 as a percentage (E0 is the electric field strength in front of the screen, Ee is the electric field strength behind the screen) for a matrix in the form of a polyethylene (PE) foil with calcium carbonate (CaCO3) painted with shielding primer.



















TABLE 9







50
2
5
10
20
50
100
200
400


No.
matrix (PE + CaCO3)
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

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% NH4Cl, 5% MgCl2 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

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.


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 (CaCO3) impregnated with various impregnating solutions, while Table 11 presents the shielding efficiency of a polypropylene nonwoven impregnated with an aqueous MgCl2 solution with various modifiers in percentage.















TABLE 10









styr.-






acrylic
silicone
acryl
PVA
without




dispersion
dispersion
dispersion
dispersion
polymer


no.
Matrix (PE + CaCO3)
[dB]
[dB]
[dB]
[dB]
[dB]





















1
2.2% MgCl2 Aqueous
x
x
x
x
10.4



solution (aq. s.)


2
2.2% MgCl2 aq. s. + 0.1%
4.4
53.7
5.3
14.7
x



polym. disp.


3
2.2% MgCl2 aq. s. + 20% polym.
6.0
46.3
5.5
42.4
x



disp.


4
2.2% MgCl2 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% MgCl2 aqueous solution
x
x
x
x
 0.6


48
MgCl2 saturated aqueous
x
x
x
x
 8.3



solution

























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% MgCl2 aqueous
84.4
68.7
54.8
40.5
25.0
14.1
8.1
5.3



solution (aq. s.)


2
2.2% MgCl2 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% MgCl2 + 0.6% Euxyl
96.5
93.6
88.5
77.9
58.1
39.1
20.3
9.3



K120 preservative


4
2.2% MgCl2 + 0.6% Euxyl
95.4
92.1
86.4
77.1
57.4
38.5
23.9
14.0



K702 preservative


5
2.2% MgCl2 + 0.6% Euxyl
96.5
93.4
93.5
78.9
59.0
41.9
26.4
15.0



9010 preservative


6
2.2% MgCl2 + 0.6%
94.5
87.6
77.2
62.5
40.9
23.2
9.9
3.4



Mystic Zen fragrance



composition








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 10−2 Hz to 106 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.
Priority Claims (1)
Number Date Country Kind
P.410462 Dec 2014 PL national
PCT Information
Filing Document Filing Date Country Kind
PCT/IB2015/059065 11/24/2015 WO 00