LU86125A1 - FLOCKED MINERALS AND WATER RESISTANT PRODUCTS MADE THEREOF - Google Patents

Description

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FLOCKED MINERALS AND WATER RESISTANT PRODUCTS MADE THEREOF

It is known that non-asbestos papers and / or webs can be produced from inorganic substances which swell in water, in particular 5 swollen silica gels. So e.g. US Pat. No. 4,239,519 describes the preparation of inorganic, crystal-containing, gellable, water-swellable leaf silicates and certain products made therefrom, such as paper, fibers, films, plates 10 and coatings. These non-asbestos papers and / or webs have good high-temperature resistance and high chemical resistance. Since no asbestos fibers are used to manufacture these products, they are also free from the health risk associated with 15 products containing asbestos.

The U.S. PS. 4,239,519 describes a three step process for the preparation of the gellable silicates which can be used for the production of the papers and webs mentioned, which consists in forming 20 (a) a completely or predominantly crystalline body which contains crystals which essentially consist of consist of water-swelling lithium and / or sodium mica, selected from the group of fluorhectorite, hydroxylhectorite, borofluorophlogopite, fluorophlogopite, 25 hydroxylborphlogopit and solid solutions thereof or

solid solutions thereof and other structurally contracted minerals • selected from the group talc, fluorine-I talc, polylithionite, fluoropolylithionite, phlogopite and Cp fluorophlogopite,

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I (b) contacted the body with a polar liquid, usually I lent water, to swell and decay the body I to form a gel and ^ 8 I (c) the ratio of solid to liquid of the 8 5 gel depending on the Set the intended use to a desired value.

8 The preferred crystalline starting materials are 8 glass-ceramic substances. These are made with substances with 8 large cations, i.e. brought into contact with an ion radius above the 8 10 of lithium, which leads to an 8 macro-flocculation of the gel and an ion exchange reaction between the large cations and the Li + and / 8 or Na + ions of the crystal interlayer.

US Pat. Nos. 3,325,340 and 3,454,917 describe the production of aqueous dispersions of vermiculite crystal flakes, which are caused by the supply of interstitial ions, namely (1) alkylammonium cations with 8 3 to 6 carbon atoms in each carbon group such as methyl B butylammonium, n-butylammonium, propylammonium and 8 20 iso-amylammonium and (2) the cationic form of amino acids such as lysine and ornithine and / or (3) lithium - 8 are swollen.

B Although the B products produced by the known processes, such as papers, webs and films, show excellent B 25 heat resistance and can be used for a variety of purposes extremely useful, they have been found to show some water sensitivity, which translates into a significant loss of strength and a general deterioration in mechanical and electrical properties when the

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Products exposed to high humidity or immersed in haters or other polar liquids. This sensitivity to water means that these products can be used for certain purposes, e.g. as head 5 or pressure seals, electrical insulators, protective coatings against environmental influences and washable building materials that are resistant to environmental influences are restricted accordingly.

It has now surprisingly been found that from a swollen, flocculated, layered silica gel, prepared by using exchangeable cations, selected from the group of guanidine derivatives, high-temperature, fire and water-resistant non-asbestos products such as sheets, papers, plates, Films, fibers and Be-15 layers can be produced. These generally surprisingly show far better results in tensile and puncture resistance tests on moist products than fabrics made using known interchangeable cations.

Furthermore, the products according to the invention generally have better electrical and mechanical properties than those produced by the known processes.

As far as heat resistance is concerned, the products according to the invention are resistant to temperatures of approx.

25 350 to 400 ° C absolutely resistant and are structure-resistant up to a temperature of approx. 800 ° C.

The products according to the invention and flocculated mineral suspensions are, according to one embodiment, using a water-swelling silicate with an I 30 average charge per structural unit of approx. -0.5 to Tÿjj approx. -1 and with exchangeable interstitial cations, 4 - 4 - <which are the swelling favor, manufactured as a starting material. The choice of the specific exchangeable cations in the starting material depends on the silicate to be used. E.g. If a synthetic gellable silicate prepared according to the method of US Pat. No. 4,239,519 is used as the starting material, the exchangeable cations are generally Li and / or Na ions. If e.g. Natural vermiculite-10 dispersion prepared according to US Pat. No. 3,325,340, the exchangeable cations generally include alkylammonium cations and the other cations specified in US Pat. No. 3,325,340. The silicate, irrespective of whether it is synthetic or natural, generally has the appearance of 15 thin scales which are disc, strip and / or ribbon-shaped. The scales usually have a length of approximately 500 to 100,000 8, preferably 5,000 to 100,000 8, a width of 500 to 100,000 8 and a thickness of less than 100 8. The expression 20 "charge per structural unit" refers to the average Charge density, as described by G. Lagaly and A. Weiss in "Determination of Layer Charge in Mica-Type Layer Silicates", Proceedings of International Clay Conference, 61-80 (1969) and G. Lagaly, in 25 "Characterization of Clays by Organic Compounds "

Clay Minerals, 16, 1-21 (1981).

The starting silicate can be produced according to the above-mentioned processes according to US Pat. Nos. 4,239,519, 3,325,340 or 3,434,917 or by other processes which produce laminates with separate layers with a charge density within the ge-ν '? desired range.

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Thereafter, the silicate is contacted with a source of at least one type of guanidine-derived cations in order to achieve an ion exchange reaction between the cations and the interstitial ions. This reaction can be carried out between the cations and the silicate material, whereby a flocculate is formed which is then used to form the products according to the invention. According to another embodiment of the invention, the starting silicate can be molded directly into the product, e.g. to lithium fluorhectorite fibers or films using the methods of U.S. Patent 4,239,519, after which the product is subjected to a cationic exchange reaction 15 using guanidine-derived cations, e.g. by immersing the product in a solution of guanidine-derived cations. The ion exchange reaction can thus be carried out in situ during the formation of the product.

The exchangeable cations which can be used according to the invention are derived from compounds of the formula f fr) * in which R, R ^ and R2 are selected from -NH2 and 25 -CH ^, with the proviso that at least two of R, and R2 are “NH2, and furthermore, in which one or more hydrogen atoms of R, Rj and / or R2 are replaced by substituents such as C ^ -C ^ alkyl, -C ^ alkenyl, -C ^ alkyny1 can and in which one or more groups SO of two such substituents together

Can form rings, which may be aromatic ^.

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The flocculated mineral suspensions according to the invention are e.g. prepared by reacting - generally with stirring - a suitable silica gel with a source of exchangeable cations derived from guanidine compounds of the formula 5 given to carry out an exchange reaction between the guanidine-derived cations and the interstitial cations in the silica gel, whereby exchanged macro-flocculate is obtained. Are e.g. the chosen exchange-10 bar cations guanidium or melaminium, that will

Silicate reacted with the corresponding hydrochloride.

As stated above, one or more exchangeable cations 15 derived from compounds of the formula mentioned can be used in the cationic exchange reaction. Since the different cations form a flocculate and possibly also end products with different physical properties, the specific cations or their combination are to be selected according to the desired end use.

20 The flocculated mineral suspension is used to form the desired end products. The individual stages of the specific treatment of the flocculate depend on the product to be molded. If it is necessary to produce the products according to the invention in the form of webs, the exchanged flocculate obtained is sufficient

The shear rate is stirred to give a particle size distribution which results in a suitable particle packing in the formation of the web. Thereafter, the flocculate is washed, if necessary, to remove any excess salt solution, after which the consistency of the flocculated slurry is adjusted to approximately 0.75 to approximately 2% solids. For better drainage on a machine screen, about Orl to about 1%, preferably 0.2 to 0.3%, based on the flocculate solids, can be added to the slurry. • Polyelectrolyte flocculant.

5 An example of a suitable polyelectrolyte flocculating agent is Polymin P, a trademark of BASF for a polyethyleneimine.

This slurry is then placed on a paper machine where it is dewatered by free dewatering and / or vacuum dewatering and finally squeezed out and dried on drum dryers.

The web obtained in this way can e.g. can be used for seals and the like.

Depending on the end use 15 of the flocculated mineral suspension, additional inert substances may be added. So e.g. For example, one or more fibers 20 from the group of natural or synthetic organic or inorganic fibers can be added to the flocculate in order to improve the degree of dewatering and to ensure an end product with increased strength and / or handling. Are e.g. the desired end products are seals, the fibers to be selected are cellulose, glass and / or Kev-lar fibers (a trademark of DuPont for an aromatic polyamide fiber). In addition, the

Flockulate to achieve a product with increased “strength latex or other binders can be added.

If the cationic exchange reaction is carried out immediately on a> 1 product formed from the silicate starting material, any desired additional inert substances are added to the starting material before the formation of the product and of course before the subsequent cationic exchange reaction added.

5 The term "water-resistant" here does not mean that the products according to the invention are water-resistant or completely water-impermeable. The expression means that the substances experience essentially no reduction in quality when exposed to water, at least in terms of their tensile and puncture resistance.

In the following examples, unless otherwise specified, the starting material used is lithium fluororectorite made by the processes of U.S. Patent 4,239,519.

15 Example 1

This example illustrates a process for making a flocculated fluorhectorite silicate exchanged with guanidinium and a sheet formed therefrom.

A slurry of "guanidinium fluorhectorite is prepared by adding 475 g of a 10% dispersion of lithium fluororectorite to 1.4 1 1N guanidine hydrochloride solution. The slurry is then stirred in a high shear mixer to reduce the particle size of the flocculate , then washed, analyzed for water content and diluted until a slurry with a solids content of 2% is obtained, after which the slurry CP is placed on a hand press tool to form a web of ""

Williams Apparatus Co. 29.21 x 29.21 cm (11.5 "x 11.5") and dewatered. The resulting web is then wet pressed and dried on a tumble dryer. The web is highly flexible 5 and shows good sealing behavior in the seal test.

Example 2

This example illustrates a process for the production of films according to the invention with cationic exchange in situ.

10 A gelled lithium fluorhectorite dispersion having a solids content of 10% is prepared in accordance with the procedures set forth in U.S. Patent 4,239,519. Then, using a 0.11 mm (4.5 mil) -Byrd applicator with a width of 12.7 cm, a 15 0.11 (4.5 mil) thick wet film of the dispersion is drawn onto a glass plate. Then the glass plate with the film adhered to it is immersed in a guanidinium hydrochloride solution (0.25 M) in order to effect a cation exchange between the guanidinium cations and the interlayer cations of the fluorine-20 hectorite. A film immediately forms on the film, indicating that the exchange has taken place. After 10 minutes the film is removed from the plate, washed in deionized water to remove the residual salts and dried. Film 25 shows high flexibility and ability to maintain strength when wet.

Examples 3 to 9 For each of these examples, the procedure according to Example 2 was essentially repeated, only that, in order to form 301 of the corresponding film, the following

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* $ »- 10 - exchangeable cations were used. In example 7 a 0.1 N solution of melamine hydrochloride was used, in all other examples a 0.25 N solution of the respective interchangeable source: 5 Example: Interchangeable cation 3 diaminoguanidine hydrochloride 4 aminoguanidine hydrochloride 5 tetramethylguanidine hydrochloride 6 methylguanidine hydrochloride 10 7 melamine hydrochloride 8. 2,6-diaminopyridine hydrochloride 9 2-aminopyridine hydrochloride

Comparative Examples 1 to 3 - These comparative examples illustrate fluorhectorite-15 films made with various known interchangeable cations. 0.11mm (4.5 mil) thick films of potassium fluorhectorite (KFH) and ammonium fluorhectorite (NH ^ FH) are made separately by the method set forth in U.S. Patent 4,239,519. Then a film is cast from both the KFH slurry and the NH ^ FH slurry. A Kymene fluorhectorite film (Kymene is a trademark of Hercules, Inc. for a cationic polyamide-epichlorohydrin resin) is then produced according to Example 2, only that a 3.0% strength Kymene solution is used and the lithium fluororectorite film is used in the Kymenel solution immersed for two hours until the interchangeable film obtained is self-supporting enough to be removed from the glass plate. These films are then 30jl together with those produced in Examples 2 to 9

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Films are subjected to a tensile and puncture resistance test, which tests are performed as follows:

Measurement of tensile strength 5 The tensile strength in the dry state is carried out using a holding device (Instron) with a claw spacing of 3.81 cm and at a crosshead speed of 0.51 cm / min. The wet strength measurement is carried out by contacting water-saturated sponges 10 with both sides of the film sample for 10 seconds, the sample being clamped in the claws of the holding device immediately before the strength test is carried out.

Puncture resistance measurement 15 A film sample is firmly clamped in a holding device. Then a pin touching the film is placed perpendicular to the surface of the film and loaded with increasing weight; * until the pin penetrates the film. In the wet test, the film is immersed in deionized water in the holding device for 10 seconds, and the puncture resistance test is performed instantaneously.

λ The results of these tests are summarized in the following 1) table: l · 3 îMMÉIB ί · II '·! · *' --------- -----. · '· - “·“. .....

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table

Film tensile strength - puncture resistance - interchangeability, MPa strength, g / iran

Cation (psi) _ 5 play dry wet dry wet

No.

2 guanidinium 98.42 63.27 7,100 4,600 (14,000) (9,000) 13 diaminoguanidinium 91.39 77.33 14,000 4,200 10 (13,000) (11,000) 4 aminoguanidinium 91.39 77.33 8,900 3,500 (13,000) (11,000) 5 Tetramethylguani- 77.33 77.33 13,000 4,400 dinium (11,000) (11,000) 15 6 methylguanidinium 36.56 19.68 6,600 3,400 (5,200) (2,800) 7 melaminium 133.57 140.60 10,000 3,300 (19,000) (20,000) 8 2,6-diaminopyridine 91.39 37.26 7,900 3,600. 20 (protein) (13,000) (5,300) 9 2-aminopyridine 77.33 49.21 7,800 3,600 (protein) (11,000) (7,000)

Comparative Example No. 25 1 Kymene 49.21 18.98 900 260 (protein) (7,000) (2,700) 2 ammonium 23.19 9.84 3,500 680 (3,300) (1,400) 3 potassium 7.73 1.41 3,300 440 30 (1,100) (200)

The test results show that the films produced by the process according to the invention are considerably higher. -5r wet tensile strength and / or wet puncture resistance show t h «- 13 - as the known compositions.

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Fire and smoke resistance

A film produced according to Example 2 is subjected to a fire and smoke resistance test after drying in accordance with the ASTM-E-662-79 method. Three separate tests are carried out.

The results are summarized below.

The numerical values correspond to the maximum optical t density, as in N.B.S. Technical Note # 708 given.

10 Test flame formation smoldering

No, _DM Corr_DM Corr_ 1 2 0 2 10 3 1 0 15 Electrical properties

The films according to Examples 2 and 7 and according to Comparative Example 3 are dried to their diameter after drying

Impact resistance tested according to the methodology of ASTM Dl49.

20 The results are summarized below: 1 film after dielectric strength, v / npri

Example 2 127.00. (5,000 v / mil)

Example 7 228.60 (9,000 v / mil)

Comparative Example 3 74.17 (2,920 v / mil) 25 Comparative Examples 4 and 5

These examples illustrate the use of silicate materials as starting material, which in their charge per structural unit and in their physical measurement results are outside the range according to the invention.

For comparative example 4, a 10% aqueous dispersion is prepared from the natural hectorite from the clay mineral warehouse of the Clay Minerals Society company, Blooming-5 ton, Indiana. For Comparative Example 5, a 10% aqueous dispersion is prepared from a sodium montmorillonite derived from the same source. In each example, a film is drawn using the 10 procedures given in Example 2. The glass plates are then immersed in a 0.25 M guanidine hydrochloride solution for 10 minutes. In both cases, there is no coherent film.

Example 10 15 This example illustrates a process for making a film of the invention using a vermiculite starting material: ""

A suspension 20 of n-butylammonium vermiculite containing 10% solids and prepared according to the process specified in US Pat. No. 3,325,340 is poured onto a glass plate according to the process specified in Example 2. Thereafter, together with the film adhering to it, it is immersed in a 0.25 M guanidinium hydrochloride solution for 10 minutes. Then the obtained film 25 is peeled off from the plate, washed and dried.

The film shows strength in the wet state in the tensile and dielectric strength test, which is not the case with a comparable non-exchanged vermiculite film.

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Example 11

This example illustrates the production of fibers using the method according to the invention. A 15% solids lithium fluorhectorite suspension prepared as above is extruded through a needle with a 0.28 mm (11 mil) die into a 2N guanidine hydrochloride solution. The extruded fiber is then conveyed into a second bath with 2N-guanidine hydrochloride using a porous belt. The 10 fibers so produced are washed by immersion in deionized water and dried. The fiber obtained proves to be firm and flexible.

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Claims (19)

1. Flocculated mineral substance, characterized in that it is a swollen layered silica gel with an average charge per structural unit of approximately -0.5 to approximately -1, which contains 5 interlattice cations representing at least some guanidine derivatives. 2. Material according to claim '1, characterized in that the silicate was produced synthetically. 3. Substance according to claim 2, characterized in that the silicate was produced by i {1) a body which consists essentially of Kristal le * '^ of 5 rrL · in water-swelling mica with the interstitial I «» * - -17 - cations of lithium and sodium exist, where the mica is selected from the group fluorhectoritr, hydroxylhectorite, borofluorophlogopite, hydroxylborphlogopite and solid solutions thereof or 10 solid solutions thereof and other structurally compatible minerals of the group talc, fluorotalk, polylithionite, fluoropolylithionite, phlogopite and fluorophlogopite contacted with a polar liquid until the crystals swell to form a gel and (2) contacted the gel thus formed at least with a cationic guanidine derivative in order to do so an ion exchange reaction between at least a part of the lithium and / or sodium cations and at least a part 20 of the guanidine derivative cations perform, 4. A substance according to claim 3, characterized in that the crystals are fluorohectorite. * * 5. A substance according to claim 3, characterized in that the polar liquid is water. 6. Material according to claim 1, characterized in that the silicate is vermiculite. 7. A substance according to claim 2 or 6, characterized in that the interstitial cations representing guanidine derivatives are selected from the group consisting of diaminoguanidine, tetramethylguanidine and guanidine, 5 aminoguanidine, methylguanidine and melamine derivatives. VtK 8. A process for the preparation of a ^ s gdQockten mineral, - 18 -, te »>» (! See material, which can be used to form a non-asbestos high-temperature- and water-resistant product according to one of claims 1 to 7 , characterized in that a swollen layered silica gel with an average charge per structural unit of approximately -0.5 to -1, which contains exchangeable interstitial ions, is contacted with at least one type of cations derived from guanidine, 10 .mu.m in this way at least carry out an ion exchange reaction between a part of the exchangeable interstitial ions and at least a part of the cations derived from guanidine. 9. The method according to claim 8, characterized in that the gel-like sheet silicate is a synthetic gellable silicate and the interstitial ions are Li + and / or Na +. 10. The method according to claim 9, characterized in that the synthetic silicate is «« produced by a body consisting essentially of crystals of a water-swelling glim-5 mers selected from the group fluorhectorite, hydroxyl hectorite, borofluorophlogopite , Hydroxylborphlogopite and solid solutions thereof or solid solutions thereof and other structurally compatible minerals, selected from the group consisting of talc, fluorotalk, polylithionite, fluoropoly-10 lithionite, phlogopite and fluorophlogopite, contacted with a polar liquid until the crystals form a Swell gels. s 11. The method according to claim 10, characterized in that the crystals are fluorohectorite. tl2. A method according to claim 10, characterized g e k e η n -. 5 1 »- · 1 - 19- indicates that the polar liquid is water. 13. The method according to claim 8, characterized g e k e η n - * characterized in that the silicate vermiculite and the interstitial ions are alkylammonium cations, the cationic form of amino acids and / or Li +. 14. The method according to claim 9 or 13, characterized in that the cations derived from guanidine are selected from the group diamino-noguanidine, tetramethylguanidine, guanidine, aminogua-5 nidine, methylguanidine and melamine derivatives. 15. High-temperature and water-resistant product, characterized in that it is made from a swollen layered silicate with an average charge per structural unit 5 of approximately -0.5 to approximately -1, which contains at least some guanidine derivatives representing interstitial cations. 16. Product according to claim 15, characterized in that it is made of a silicate flock lat. 17. Product according to claim 15 or 16, 'characterized in that it represents a web. 18. Product according to claim 15 or 16, characterized in that it is a fiber material. 19. Product according to claim 15 or 16, characterized in that it is a film. 20. A process for producing a high-temperature and water-resistant silicate product, characterized geke η n - ^ (draws that a layered silicate which can be swellable in ** K φ -20- water and has a charge of 5 structural units of approx. -0 , 5 to about -1 and exchangeable interstitial ions produced product contacted with at least one type of guanidine-derived cations in order to carry out an ion exchange reaction between at least a portion of the guanidine-derived cations 10 and at least a portion of the interstitial ions ^^^^ ^ "1" *