FI92216B - Fire Protective Coating Composition - Google Patents

Description

92216

FIRE PROTECTIVE COATING COMPOSITION

The invention relates to a coating composition for fire protection of various building elements, in particular steel structures.

At present, e.g. fire-fighting paints and fire-fighting paints.

The fire protection properties of fire protection paints are usually based on the fact that they swell when heated. Fire protection paints usually contain organic compounds, whereby the organic components react with each other under the influence of heat and the result is a carbonized porous foam layer which acts as an insulator 15 and generally protects the structures for up to about 30 minutes.

Similar insulation materials that may swell in the event of a fire also include materials that contain water glass, i. alkali metal silicate, and which can be used as a coating or adhesive for building elements 20. For example, DE 3506132 discloses a mass to be used as a coating or adhesive, which contains e.g. water glass and an organic binder. Application publication FI 921492 discloses a binder containing alkali metal silicate. . And an acid-treated excipient, and an expandable composition containing such a binder.

Furthermore, the patent publication FI 86738 describes a mixture for use as a coating or adhesive, which contains water glass and blast furnace slag, such that the proportion of water blast furnace slag is 65 to 99% by weight and the proportion of blast furnace slag is 0.5 to 30% by weight. In the application examples, the mixture also contains cellulose. The target protection time of the mixture is of the order of approx. 25 min.

A disadvantage of the known water-glass-containing insulating materials is that the water-glass does not withstand heat well, but when heated it begins to melt, breaking the surface of the insulating material and thus shortening the fire protection time of the coating 2 92216. Thus, insulating materials containing water glass are generally only suitable as protective cladding materials.

Of the various insulation materials, mention may also be made of U.S. Pat. No. 4,990,945, which discloses a support / sealing material for use in mines. Ko. the material contains 40 to 95% by weight of water glass, 0.05 to 4% by weight of perlite and mineral acid and also has a short fire-retardant effect on the type of protective cladding materials. Furthermore, U.S. Pat. No. 5,045,385 discloses a cured and pressed protective upholstery element consisting of vermiculite or perlite, glass fibers, a water glass binder and curable phenofin resins. These have the above-mentioned disadvantages and mainly represent the protective cladding material.

The fire protection property of fire protection masses, in turn, is mainly based on low thermal conductivity. The masses currently used are mainly expanded insulators containing expanded vermiculite. The target protection time of insulation compounds is longer than the protection times of protective cladding materials.

An example of a fire retardant for steel is the mass described in EP 400162, in which vermiculite has been replaced by cheaper raw materials. The mass does not swell in a fire situation. Insulation thicknesses of the order of 1-2 inches are recommended for steel \ fire protection, which can be considered impractical.

U.S. Pat. No. 4,113,325 discloses an sprayable fire retardant coating comprising a porous water glass matrix and unexpanded crude vermiculite or unexpanded perlite. The porous water glass matrix is formed of an alkali metal silicate, sodium silicofluoride, a gelling agent such as a low molecular weight amide or haloalcohol, and a fiber such as glass 3 92216 fiber. Based on current legislation, the harmful components of the composition are fiberglass and sodium silicofluoride, which in the event of a fire form toxic fluorine compounds.

5 FI 73716 further discloses an aqueous dispersion latex of a polymeric binder and a vermiculous filler for corrosion and fire protection.

The disadvantage of vermiculite-based fire retardants 10 is that the coating must be made relatively thick in order to obtain a longer-lasting fire retardant. In addition, there is still room for improvement in the mechanical strength of such coatings.

The object of the present invention is to eliminate the above-mentioned drawbacks.

It is a particular object of the invention to provide a flame retardant coating composition which, thanks to a novel combination of ingredients compared to previous compositions, provides a flame retardant coating which adheres excellently to the surface of the object, is mechanically strong and has at least one hour of fire protection.

For aspects of the invention, reference is made to the claims.

. The invention is based on the idea of combining a modified water glass, i. silicophosphate, blast furnace slag and vermiculite concentrate, and possibly phlogopite and / or pigment together, so as to obtain a new type of fire protection coating which expands in the event of fire due to its pyroplastic properties and also provides: surprisingly long-lasting fire protection.

The proportion of silicophosphate as a binder in the fire protection coating composition according to the invention is 43 to 76% by weight, preferably 46 to 65% by weight, and the proportion of powdered filler consisting of machine slag and vermiculite and possibly phlogopite and / or pigment is 24 to 57% by weight. , preferably 35 to 50 4 92216 wt%, by weight of the composition.

The filler mixture preferably contains finely ground blast furnace slag 5-15% by weight, more preferably 8-14% by weight, vermiculite concentrate 5-30% by weight, more preferably -5 min 8-14% by weight, phlogopite 0-15% by weight, more preferably 8 - 14% by weight, pigment 0-9% by weight, more preferably 5-8% by weight, by weight of the composition.

The flame retardant coating according to the invention preferably also contains a hardener of 2 to 10% by weight, more preferably 4 to 10% by weight, such as 4 to 6% by weight, of the weight of the binder.

The silicophosphate binder is obtained by reacting a water glass, which in this context means an alkali metal silicate such as sodium or potassium silicate, with potassium tripolyphosphate at an elevated temperature. The density of the water glass used as starting material is preferably at least on the order of 1.4 g / cm 3. Potassium tripolyphosphate is used in an amount of about 7 to 10% by weight of water glass.

In the flame retardant coating composition of the invention, silicophosphate has been found to penetrate very well between the granules of the powdered filler, which advantageously affects the integrity and continuity of the coating formed from the composition. The binder used also acts as a plasticizer, increasing the strength of the coating to be formed. Furthermore, the silicophosphate contained in the composition is more resistant to high temperatures, e.g. unmodified water glass.

The blast furnace slag used is preferably granulated blast furnace slag having a grain size of less than about 0.5 mm. Blast furnace slag has a very advantageous effect on the swelling properties of the coating to be formed and on the strength of the coating.

The vermiculite concentrate is preferably expanded vermiculite having a grain size of less than about 1 mm. 35 Vermiculite concentrate can be partially replaced by a cheaper raw material such as phlogopite. Vermiculite and phlogopite are used in the composition of the invention.

II

5,92216 as a heat insulating material.

The composition may also contain a pigment to produce the desired color. A particularly preferred pigment is zinc oxide and / or titanium dioxide, which have a beneficial effect on fire protection properties.

The hardener can be used to accelerate the drying speed of the coating to be formed. As the hardener, any of the hardeners known in the art can be used, which produce non-toxic combustion products in the event of a fire. Such hardeners include, for example, condensed aluminum phosphate, A1 (PO3) 3, and inorganic and organic acids such as carbonic acid, oxalic acid, tartaric acid, etc. Oxalic acid is a particularly useful hardener.

The flame retardant coating composition may also contain other additives known in the art.

In practice, the fire protection coating composition according to the invention is preferably a so-called in the form of a two-component preparation, wherein the dry filler mixture, optionally doped with a hardener, and the liquid silica-phosphate binder are mixed together just prior to application to the surface of the subject.

The invention also relates to a method of applying said fire protection coating composition to the surface of an object 25 and to a fire protection coating formed by the method.

Thanks to the advantageous combination of ingredients and the grain sizes used, the flame retardant coating mixture is easy to handle and can be applied to the surface of the object, e.g. by spraying, whereby the coating takes place conveniently and quickly.

When a hardener is used, the liquid silicophosphate binder and the filler mixture containing the hardener are combined and the resulting mixture mass is immediately applied to the surface of 35 objects. The curing of the applied coating is accelerated by the reaction of the silicophosphate binder with the hardener, resulting in a polysilicate chain that determines the curing of the coating. In this case, the curing of the applied layer takes only a few hours, after which a new layer can always be applied on top of the layer to obtain the desired coating thickness.

5 As the coating dries and cures, the binder binds the granules of the filler mixture and the potassium tripolyphosphate contained in the silicophosphate reaction product acts as a plasticizer to release internal stresses in the material and increase the mechanical strength, adhesion to the target surface and temperature resistance.

The mineralologically hardened and dried fire protection coating according to the invention consists of an amorphous and a crystalline phase.

In the event of a fire, the fire retardant coating composition of the invention expands due to the reaction between silicophosphate and blast furnace slag. The coating expands approx. 2 - 2.5 times. Because of the good heat resistance of silicophosphate, the expanded layer lasts longer than the expandable materials containing water glass, producing longer fire protection. The vermiculite concentrate used and any phlogopite used increase the fire protection when acting as thermal insulation. Furthermore, when the fire retardant coating composition contains Pigment-25 tin zinc oxide, the zinc oxide reacts in a fire-binding manner to form a zinc silicate, i. willemite.

The fire protection coating composition according to the invention does not produce toxic combustion products in the event of a fire. The fire protection coating composition according to the invention can be used as a heat-expandable fire protection word for various building elements, in particular steel structures, in order to provide long-lasting fire protection. Thanks to the invention, a relatively thin pin-35 weft layer thickness, on the order of 10 to 12 mm, provides at least one hour of fire protection.

. A further advantage of the invention is that it is provided. · · Li 7 92216 A highly useful fire retardant coating composition compared to the prior art utilizing an inexpensive blast furnace slag. The usefulness of the composition according to the invention is enhanced by its environmental friendliness.

The invention is illustrated in more detail by the following examples. The examples merely illustrate the invention without limiting it.

Example 1; Chemical-mineralogical structural studies of a fire protection coating according to the invention

The specimens were coated by spraying a flame retardant coating composition containing: silicophosphate binder 56.25 wt% 15 blast furnace slag 12.5 vermiculite concentrate 12.5 phlogopite 12.5

ZnO (GOST 202-84) 6.25 (dry matter content 43.75 wt%).

20

The ground blast furnace slag (Rautaruukki Oy) used in the composition had the following properties:

Chemical composition,%: 25 Na 2 O 0.77

MgO 10.5 Al 2 O 3 7.86

Fe 0.36 S 1.79 30 CaO 38.9

Ti 1.37

SiO 2 36.5 8 92216

Raeluokkajakautuma:

Grain class Proportion +0.5 mm 0.0 5 +0.297 - 0.5 12.8 +0.210 - 0.297 25.4 +0.149 - 0.210 16.2 +0.105 - 0.149 13.5 +0.074 - 0.105 9.6 10 + 0.053 - 0.074 5.3 -0.053 17.3 The vermiculite concentrate and phlogopite used had the following properties: 15

Vermiculite concentrate KVK-1 Phlogopite SFE-315 (Kovdor), grain size less than 1 mm:

Chemical composition,% Chemical composition,% 20 SiO2 38.62 SiO2 40

TiO 2 0.8 MgO 22 Al 2 O 3 12.15 Al 2 O 3 16

Fe 2 O 3 6.29 Fe 2 O 3 7

FeO 0.02 K 2 O + NazO 9 25 CaO 1.82 P 2 O 5 0.1

MgO 27.76 loose weight K20 0.44 not more than 0.5 g / cm3 free water 11.40 9 92216

The silicophosphate binder was prepared by reacting sodium water glass having a density of at least 1.4 g / cm 3 with potassium tripolyphosphate in a proportion of 7 to 10% by weight of the water glass at 80 ° C. The chemical composition of the obtained silicophosphate was as follows,%:

SiO 2 26.2

Na 2 O 9.5 P 2 O 5 2.43 10 K 2 O 2.50.

The coating was dried. The chemical composition of the cured coating was obtained:

Component Concentration,% 15 MgO 12.8 Al 2 O 3 6.25

SiO 2 38.3

Fe 1.8

Na 2 O 7.85 20 P 2 O 5 2.77

Zn 6.03 K 2 O 5.13

CaO 7.58 C 0.4 H 2 O 9.5

Density 1750 - 1800 kg / m3

Porosity 11.7%

Mineral determinations were performed on the X-ray diffraction fraction. The cured coating consisted of an amorphous and a crystalline phase. The amorphous phase was slag and the modified water glass used in the invention. From the crystalline phase, mica, vermiculite, zincite, portlandite and calcite were identified. Portlandite and calcite are clear products of hydraulic reactions. 35 As a result of the hydraulic reactions, about 3% of the calcite had formed.

. Melite, forsterite, willemite and mica were identified from the coating that was subsequently subjected to the combustion test described in Example 5.

Example 2: Investigation of the effect of added hardeners

The effect of oxalic acid and aluminum phosphate (LP-AN 212, Hoesch) on the curing of a flame retardant coating composition according to the invention was investigated in the experiment.

The composition used contained: silicophosphate binder 53.1 wt% blast furnace slag 13.4 vermiculite concentrate 13.4 15 phlogopite 13.4

ZnO 6.7 (dry matter content 46.9 wt%)

Upon addition of 3 to 6% by weight of oxalic acid to the resulting mixture, the mixture sprayed as a coating was cured in a few hours so that it could be coated with the next layer. For example, the addition of 4% by weight of oxalic acid had hardened the coating sufficiently after about 3-4 hours so that the next layer could be sprayed on it.

,. 25 Aluminum phosphate gave similar results when used in slightly higher amounts, on the order of 4-8 wt%.

Example 3: Examination of the properties of some fire protection coatings according to the invention and coatings containing water glass as a binder

The following Tables 1 and 2 summarize examples of coatings formed with the compositions of the invention and the properties determined therefor. As a comparative example, similar coatings have been used in which water glass has been used as a binder.

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The results show the advantage of coatings formed with the flame retardant coating compositions of the invention. In contrast, it is seen that coatings in which water-5 has been used as a binder have a long curing time and when such coatings are burned on water glass there is a tendency to melt from the surface.

Example 4: Mechanical properties of a fire retardant coating according to the invention Metal substrates were coated with the fire retardant coating composition shown in Example 2.

Adhesion to the object: The method involved the uniform tearing of the coating from the substrate, the measurement of the force required for it and the determination of the type of breakage. The experiment was performed on five samples. The average re-breaking strength was 46.3 kp / cm2.

Based on the results obtained, the adhesion of the coating is excellent.

Test of resistance to temperature differences in the coating: The coated test piece was kept at -20 ° C for 16 h, then at +60 ° C for 8 h and this was repeated 30 times. The coating was found to remain strong without visible damage, its adhesion to the metal remained unchanged.

In addition, the impact resistance of the cured fire retardant coating was excellent compared to traditional vercululite-based compounds.

Example 5: Combustion experiments 30 Two combustion experiments were performed.

The test according to the requirements of section 5.1 of SEV standard 1000-78 "Fire protection standards for building design, fire resistance testing method for building materials" was performed with the fire protection coating composition shown in Example 2. Coating thicknesses of about 9.9 mm and 10.1 mm were used in the experiments. No cracks, ignition, combustion or smoke formation of the fire protection coating was observed in the experiment. Prior to the end of the fire test (approx. 70 min), there were no significant changes in the behavior of the fire protection coating.

The second combustion test was a fire resistance test in a cube furnace performed at VTT's Fire Technology Laboratory la-5. The experiment was performed using spray-protected, unloaded steel plates. The standard SFS 4193 (ISO 834, Nordtest method NT FIRE 005) was applied in the experiment. The protection was performed with three sprays of 10 so that the mass ratio of dry matter to liquid binder was 45:55 for the first spray and 48:52 for the 2nd and 3rd sprays. The coating thicknesses and the results obtained for each sample are shown in Table 3.

15 TABLE 3

Time STEEL AMOUNT MODELS AVERAGE VALUES (* C) AND MAX. VALUE (· <!]) F mini

Levy 1 Lny 2 Levy 3 Levy 4

Steel plate 5 tm Steel plate 5 se Steel plate 10 m Steel plate 10 m

Insulator 8.9 hi Insulator 12.3 se Insulator 8.4 in Insulator 11.7 n 0 20 20 20 20 10 101 (101) 73 (76) 92 (97) 63 (64) 20 146 (153) 97 (100 ) 135 (135) 101 (101) '30 291 (293) 111 (119) 217 (239) 122 (130) 40 395 (398) 228 (241) 298 (322) 208 (217) 50 481 (485) 330 (344) 375 (398) 291 (303) 80 918 (926) 660 (668) 765 (799) 694 (749) »17 9221 6

During the combustion tests, the coating began to swell after about 4 minutes had elapsed since the beginning of the test.

When examining the excretion of volatile harmful substances, no formation of harmful gases was observed.

The experiments show that the protection capacity of the steel structures of the fire protection coating according to the invention is at least about 1 h.

Example 6: Preparation of a fire retardant coating composition according to the invention and application of the obtained mass to the surface of a steel structure 13.4 kg of finely ground blast furnace slag, 13.4 kg of vermiculite concentrate, 13.4 kg of phlogopite, 6.7 kg of zinc oxide and 2.1 kg of oxalic acid ( hardener) is mixed thoroughly in a ball mill for 30 min.

46.9 kg of the dry mixture obtained are introduced into a batch mixer and 53.1 kg of a silica-phosphate binder prepared as described in Example 1 and having a density of 1.48 g / cm 3 are added. The mixture is immediately applied to a syringe pump wood known per se and sprayed onto the surface of the steel structure in accordance with industry practice. Steel structures can have a subsoil if desired. The spraying is carried out so that the layer thickness 25 is about 4 to 5 mm. After 3 to 4 hours, the viscosity of the coating is so high that spraying can be repeated on the first coating layer. Spraying is performed a total of 3 times. If necessary, the spraying can be carried out, for example, in two steps. The coating is then allowed to dry. The thickness of the obtained coating is 10 to 12 mm. The hard coating provides at least about 1 h of fire protection.

One of the advantages of the fire protection coating composition according to the invention is its rapid curing, so that the necessary spraying operations can be carried out, for example, during one shift.

Claims (14)

922Ί6 A flame retardant coating composition consisting mainly of a liquid binder and a mixture of powdered fillers, characterized in that the binder is silicophosphate and the filler mixture comprises blast furnace slag, vermiculite concentrate and optionally phlogopite and / or pigment in a binder content of 24 to 76% by weight - 57% by weight of the composition. Composition according to Claim 1, characterized in that the composition swells on heating. Composition according to Claim 1 or 2, characterized in that the filler contains: finely ground blast furnace slag about 5 to 15% by weight of vermiculite concentrate about 5 to 30% by weight phlogopite about 0 to 15% by weight pigment about 0 to 9% by weight of the composition. Composition according to one of Claims 1 to 3, characterized in that the composition contains 2 to 10% by weight, preferably 4 to 8% by weight, of hardener, based on the weight of the binder. Composition according to one of Claims 1 to 4, characterized in that the grain size of the blast furnace slag is less than 0.500 mm. Composition according to one of Claims 1 to 5, characterized in that the vermiculite concentrate has a grain size of less than about 1 mm. · :. Composition according to one of Claims 1 to 6, characterized in that the pigment is zinc oxide, titanium dioxide and / or another suitable pigment. Composition according to one of Claims 1 to 7, characterized in that the hardener is I! * 22) 6 condensed aluminum phosphate or an inorganic or organic acid, preferably oxalic acid. Composition according to one of Claims 1 to 8, characterized in that the silicophosphate binder is obtained by reacting a glass of water with potassium triphosphate. A method of applying a flame retardant coating composition according to claim 1 to a surface of an object, characterized in that a liquid silicophosphate binder is mixed with a blend mixture of blast furnace slag, vermiculite concentrate and optionally phlogopite and / or pigment and the resulting flame retardant is applied to the surface. A method according to claim 10, characterized in that the silicophosphate binder is mixed with a filler mixture doped with a hardener and the obtained flame retardant coating mass is applied immediately to the surface of the object. Method according to Claim 10 or 11, characterized in that the fire-retardant coating composition is applied, for example, by spraying. Method according to one of Claims 10 to 12, characterized in that the fire-retardant coating composition is sprayed in three layers to form a coating with a thickness of 10 to 12 mm. Fire protection coating formed by a method according to one of Claims 10 to 13, characterized in that the coating produces a fire protection of at least 1 h in a layer thickness of about 10 to 12 mm. 92216