CN1394923A - Water thin type expanding steel structure fire-resisting paint and its preparation method - Google Patents

Abstract

The present invention relates to a water thin expanding steel structure fire-resisting coating material and its preparation method. Said ivnention adopts a self-synthesized high melting temp. acrylate emulsion as main film-forming substance, adding proper quantity of chlorometaemulsion to raise fibre resistance of film-forming substance self-body, and on the basis of convertional ammonium polyphosphate fire-resistant adjuvant an expandable graphite as foaming material is added so as to form the invented fire-resisting coating material. Said invention can greatly raise forming rate to coating layer, the thickness of foamed layer can be up to 30-50 times that of original coating layer, and its fire-resisting limit can be up to 75 min (thickness of coating layer is 3 mm).

Description

Water-based thin intumescent steel structure fireproof coating and preparation method thereof

Technical field

The invention relates to a steel structure fireproof coating. The present invention further relates to a preparation method of the fireproof coating for steel structures.

Background technique

There are many types of fire-resistant coatings for steel structures, which can be divided into three types: water-based, solvent-based and powder-based according to their material forms; thick, thin and ultra-thin according to the coating thickness; The mechanism can be divided into three types: thermal insulation type, expansion type and non-expansion type. At present, the commonly used fireproof coatings for steel structures are mainly classified into three types: thick type, thin type and ultra-thin type:

Thick steel structure fireproof coating: the coating thickness is between 8-50mm, and the fire resistance limit is 0.5-3h. It is a heat-insulating fireproof coating. Rock, etc.) and flame retardants. Although this type of coating is currently the largest and most widely used type of fire-resistant coating, and can reduce the flame propagation speed in the early stage of combustion, it will lose its effect once the fire is strong, so it is generally used for fire prevention. of buildings.

Thin fireproof coatings for steel structures: fireproof coatings with a coating thickness of 3 to 7mm are called thin fireproof coatings, and their fire resistance limit is 0.5 to 1.5h. They are mainly composed of polymer resins, carbon forming catalysts, carbon forming agents, foaming agents and Composed of inorganic fillers, etc., it is an intumescent fireproof coating. This kind of paint has thin coating, small dosage per unit area, strong fireproof function and good decorative effect, so it is the development direction of fireproof paint.

Ultra-thin fireproof coating for steel structures: The coating thickness of ultra-thin fireproof coating is not more than 3mm, and the fire resistance limit is within 2h. The film-forming substances and fire retardant additives of this type of coating are basically the same as those of thin fire retardant coatings, but in the preparation process, measures are taken to increase the fineness of fire retardant additives in the coating, so that the coating has better leveling properties and increases the coating's durability. Decorative appearance. This type of coating is also the development direction of fire retardant coatings.

The components of the existing water-based thin intumescent fireproof coatings for steel structures include ordinary styrene-acrylic emulsions, chlorine partial emulsions (or chlorine partial emulsions alone), ammonium polyphosphate, melamine, pentaerythritol, and inorganic fillers and coalescents . The specific process is to mix and grind ordinary propylene benzene emulsion, chlorine partial emulsion, and fireproof additives. Although this kind of steel structure fireproof coating has become the development direction of fireproof coating due to its thin coating and good performance, because the fireproof additives used in this water-based thin intumescent fireproof coating are mainly organic compounds, its fire resistance temperature is not high. At the same time, the softening temperature of the film-forming material used in this type of fire retardant coating is relatively low, and the foamed layer is relatively loose after burning, and it is easy to fall off under flame erosion. In addition, the compatibility between the film-forming substance and the fire protection additive is not good enough, and the melting temperature of the film-forming substance is often not the foaming start temperature of the fire protection additive, so the expansion rate of the coating is low, generally only its own thickness 10 to 20 times of that. Therefore, the fire resistance limit of the steel structure water-based thin-coated intumescent fireproof coating made of the above-mentioned ordinary propylbenzene emulsion, chlorine partial emulsion, and fireproof additive is only 30 minutes, which cannot reach the level of cement-based thick fireproof coating, thus limiting them. scope of application.

Contents of invention

The technical problem to be solved by the present invention is to find a kind of high-efficiency water-based thin-type intumescent fireproof coating with good foaming performance and tight combination between the foamed layer and the steel structure after combustion, and with the level of thick fireproof paint, so as to meet the requirements of high steel structure. Fire-resistant coatings for fire-resistant requirements.

The present invention also solves the preparation method of this fireproof coating.

In order to solve the above-mentioned technical problems, the present invention is carried out like this: the coating composition of the present invention adopts self-synthesized high-melting temperature acrylate emulsion as the main film-forming substance, and it is mixed with chlorine partial emulsion to improve the flame retardancy of the film-forming substance itself, In particular, expandable expandable graphite has been selected as the expansion agent, as well as ammonium polyphosphate fire protection additives, fillers and film-forming additives. Among them: ammonium polyphosphate fire protection additives are ammonium polyphosphate, melamine and pentaerythyl alcohol; filler is zinc oxide;

Coating composition proportioning of the present invention is as follows:

Component Content (wt%)

Water-based high melting temperature acrylate emulsion 32～38

Chlorine partial emulsion 12～18

Ammonium polyphosphate 17～20

Ammonium melamine 5～7

Pentaerythritol 11～13

Expanded graphite 4～10

Zinc oxide 0～6

Coalescing agent 0～6

Preparation technique of the present invention comprises following two steps:

The first step is the synthesis of high melting temperature acrylate emulsion: first select the following components:

The monomer is: p-halomethylstyrene (the halogen atom can be a chlorine atom or a bromine atom);

Methyl methacrylate; Butyl acrylate; Acrylic acid.

The emulsifiers are: sodium lauryl sulfate and nonylphenol polyoxyethylene ether (OP-10);

The initiator is: ammonium persulfate. Then weigh according to the following component content (emulsifier, initiator and water are calculated by monomer total amount %):

Category Component Content (wt%)

Monomer Methyl methacrylate 40～46

Butyl acrylate 40～46

Acrylic 2～4

4 ～ 18 of chlor -based styrene 4 ～ 18

      4-18 p-bromomethyl styrene

Emulsifier Sodium Lauryl Sulfate is 1~3 of the total amount of monomers

   Nonylphenol polyoxyethylene ether (OP-10) is 3-6 of the total amount of monomers

Initiator ammonium persulfate is 1~2 of the total amount of monomers

Water 100

Mix the monomer, emulsifier and water uniformly first, then add the initiator, control the polymerization temperature to 70-85°C, and the polymerization time to be 4-6 hours to obtain the high melting temperature acrylate emulsion of the present invention. The melting temperature of the polymer is 125-135°C and has the following chemical structure: Wherein X is Cl or Br; n, m, p, q are positive integers greater than 0.

The second step is the preparation of fireproof coatings: the self-synthesized high-melting temperature acrylate emulsion and chlorine partial emulsion are used as film-forming substances; polyphosphate amine, melamine and pentaerythritol are used as fireproof additives. First, after weighing the components of the fire retardant coating according to the present invention, first put the emulsion, fire retardant additives, fillers and film-forming additives together and stir and mix for 20-30 minutes, then add the above-mentioned components after grinding by a sand mill The expandable expanded graphite can be mixed uniformly to obtain the finished product of the present invention.

The present invention has following advantage:

1. Since the fireproof coating of the present invention is on the basis of commonly used ammonium polyphosphate fireproof additives, a kind of expandable expanded graphite is added as the foaming material. This expanded graphite is a type of natural mineral material with metallic luster , gray-black, soft and greasy, scale-like, violently foams and expands when heated above 200°C, and the expansion rate can reach up to 350 times its own volume, thus greatly improving the foaming rate of the coating, the foaming layer The thickness can reach 30 to 50 times the thickness of the original coating, thus improving the fire resistance limit.

2. Since the fireproof coating of the present invention adopts self-synthesized high-melting temperature acrylate emulsion as the main film-forming substance, an appropriate amount of chlorine partial emulsion is mixed into it, compared with the existing emulsion that simply uses chlorine partial emulsion as the film-forming substance. The flame retardancy of the film substance itself is improved. In addition, the methyl methacrylate and p-halomethylstyrene used in the preparation of the high melting temperature acrylate emulsion of the present invention, especially the latter, have made a great contribution to improving the melting temperature and the bonding rate of the coating. Its fire resistance limit is increased from the existing 30min to 75min (coating thickness 3mm).

3. The preparation process of the present invention is simple, pollution-free, low in cost and widely used.

Detailed ways

The technical solutions of the present invention will be further described below in conjunction with the examples.

Example 1

Preparation of high melting temperature acrylate emulsions. Please refer to Table 1 for the formulation of the high melting temperature internal acrylate emulsion of the present invention and the existing common styrene-acrylic emulsion formulation. First, prepare according to the formula of high melting temperature acrylate emulsion 1 in Table 1. Weigh the monomers in component A, then weigh water and emulsifier according to the weight percentage of the total amount of monomers, and mix and stir together to form pre-emulsion A. Weigh the water and initiator in component B according to the weight percentage of the total amount of monomers in Table 1, mix and dissolve to obtain solution B. Then, the water of component C is weighed according to the weight percentage of the total amount of monomers, and then added to the reactor, and the reactor is placed in a water bath to keep the temperature at 75°C, and about 1/5 of the pre-emulsion A and about 1/5 of the Solution B, stirred for about 0.5h. When the reaction system appears slightly blue, start to drop the pre-emulsion A and solution B simultaneously. The dropwise addition was completed in about 3 hours. Then keep it warm at 85°C for 1 hour, remove the water bath, cool to below 40°C, add ammonia water to adjust the pH value to 8, and discharge for later use. The resulting product had an initial melting temperature of 134°C.

Example 2

High melting temperature acrylate emulsion 2 was prepared according to the formula in Table 1. The preparation method is the same as Embodiment 1. The resulting product had an initial melting temperature of 131°C.

Example 3

Please refer to Table 2 for the 4 formulations of fire retardant coatings of the present invention and one of the existing comparative formulations. First, according to formula 1 in table 2, the high melting temperature acrylate emulsion 1 prepared by embodiment 1 weighed 36% by weight, and 15% of chlorine partial emulsion, 20% of ammonium polyphosphate, 7% of ammonium melamine, 13% of pentaerythritol, 4% of expanded graphite, 3% of zinc oxide and 2% of film-forming aids should be weighed. Then, first add the high melting temperature acrylate emulsion into the mixing tank, add the three kinds of fire prevention aids, zinc oxide and film-forming aids of the present invention under stirring, after stirring evenly, grind it in a sand mill, and then add expanded graphite , mixed evenly, and discharged into barrels. The properties of the resulting arson coating of the present invention are shown in Formulation 1 of Table 3. From the performance item of table 3 and compare with the performance of existing coating, reached the purpose of the present invention.

Example 4

According to formula 2 in table 2, adopt the same method of embodiment 3 to prepare fireproof coating. The properties of the resulting coatings are shown in Table 3, Formulation 2.

Example 5

According to formula 3 in table 2, adopt the same method of embodiment 3 to prepare fireproof coating. The properties of the resulting coatings are shown in Table 3, Formulation 3.

Example 6

According to formula 4 in table 2, adopt the same method of embodiment 3 to prepare fireproof coating. The properties of the resulting coatings are shown in Table 3, Formulation 4.

Because the present invention has adopted expanded graphite as expansion agent, adopts self-prepared emulsion at the same time, these two aspects are improved to existing water-based thin expansion fireproof coating, produced the advantage as shown in Table 3, and cost is low, and preparation process is simple , can be widely used in various steel structure fire prevention.

comparative example

Prepare common styrene-acrylic emulsion by the formula of table 1. Mix and stir the monomer, water and emulsifier in component A to form pre-emulsion A. Mix and dissolve the water and initiator in component B to obtain solution B. Add the water of component C into the reactor, and place the reactor in a water bath to keep the temperature at 75°C, add about 1/5 of the pre-emulsion A and about 1/5 of the solution B, and stir for about 0.5h. When the reaction system appears slightly blue, start to drop the pre-emulsion A and solution B simultaneously. The dropwise addition was completed in about 3 hours. Then keep it warm at 85°C for 1 hour, remove the water bath, cool to below 40°C, add ammonia water to adjust the pH value to 8, and discharge for later use. The resulting product had an initial melting temperature of 116°C.

According to the formula of the comparative example in Table 2, add water into the mixing tank, add the fire prevention additive under stirring, after stirring evenly, put it into a sand mill for grinding, and discharge the material into a barrel. The properties of the resulting coatings are shown in Table 3.

Table 1 Preparation formula of high melting temperature acrylate emulsion of the present invention and common styrene-acrylic emulsion formula (wt%) raw material name High Melting Temperature Acrylate Emulsion 1 High melting temperature acrylate emulsion 2 Ordinary styrene-acrylic emulsion A monomer Methyl methacrylate 45 44 ~ Butyl acrylate 44 43 54 acrylic acid 2 4 2 p-Chloromethylstyrene 9 ~ ~ p-Bromomethylstyrene ~ 9 ~ Styrene ~ ~ 44 Emulsifier Sodium dodecyl sulfate 2 1 1～3 OP-10 4 6 3～6 water 85 85 85 B Initiator ammonium persulfate 1 2 1～2 water 10 10 10 C water 5 5 5 # all account for the weight % of monomer total amount

Table 2 Water-based thin coating intumescent fire retardant coating formula and comparative example of the present invention raw material name Recipe 1 Recipe 2 Recipe 3 Recipe 4 comparative example Ordinary styrene-acrylic emulsion ~ ~ ~ ~ 32～38 High Melting Temperature Acrylate Emulsion 1 36 37 35 33 ~ Chlorine partial emulsion 15 13 14 18 12～18 Ammonium polyphosphate 20 19 18 17 twenty two Melamine 7 6.5 6 5.5 8 pentaerythritol 13 12.5 12 11.5 14 expanded graphite 4 6 8 10 ~ Zinc oxide 3 2 6 0 0～6 Coalescent 2 4 1 5 0～6

Table 3 The main properties of the fire retardant coating of the present invention and the comparison with existing coatings performance item Recipe 1 Recipe 2 Recipe 3 Recipe 4 comparative example Drying time (h) 5 4 2.5 2 6 Initial drying crack resistance no crack no crack no crack no crack A small amount of very fine cracks Adhesive strength (MPa) 0.75 0.68 0.50 0.63 0.24 Water resistance (h) >24 >24 >24 >24 >24 Freeze-thaw stability (times) >15 >15 >15 >15 >15 Moisture and heat resistance (h) 280 300 340 400 250 Fire resistance Coating thickness (mm) 3 3 3 3 3 Foam layer thickness (mm) 85 98 108 120 28 Fire resistance limit(min) 54 60 66 75 30

Claims (3)

1. water thin type expanding steel structure fire-resisting paint is characterized in that: by synthetic high melting temperature acrylic ester emulsion voluntarily, and ammonium polyphosphate class fire proofing additive and expandability expanded graphite, and be aided with filler and film coalescence aid is formed;

Wherein: ammonium polyphosphate class fire proofing additive is ammonium polyphosphate, melamine and tetramethylolmethane; Filler is a zinc oxide;

Concrete composition proportioning is as follows:

Component concentration (wt%)

Water-based high melting temperature acrylic ester emulsion 32～38

Chlorine partial emulsion 12～18

Ammonium polyphosphate 17～20

Melamine 5～7

Tetramethylolmethane 11～13

Expanded graphite 4～10

Zinc oxide 0～6

Film coalescence aid 0～6

2. steel structure fire-proof paint according to claim 1 is characterized in that: the melt temperature of olefin(e) acid ester emulsion is 125～135 ℃ in the described high melting temperature, and its chemical structure is: Wherein X is Cl or Br; N, m, p, q are the positive integer greater than 0.

3. the preparation method of a water thin type expanding steel structure fire-resisting paint is characterized in that: comprise following two steps:

The first step: high melting temperature preparing acrylate emulsion, the monomer of employing be methyl methacrylate, butyl acrylate, vinylformic acid, to monochloromethyl vinylbenzene; Wherein the halogen atom in the monochloromethyl vinylbenzene be can be chlorine atom or bromine atoms; The emulsifying agent that adopts is sodium lauryl sulphate and polyoxyethylene nonylphenol ether (OP-10), and initiator is an ammonium persulphate; At first select following component and weighing good, wherein the content of emulsifying agent, initiator and water is the wt% of monomer total amount:

Classification component concentration (wt%)

Monomers methyl methacrylate 40～46

Butyl acrylate 40～46

Vinylformic acid 2～4

To monochloromethyl vinylbenzene 4～18

Emulsifier sodium lauryl sulfate 1～3

Polyoxyethylene nonylphenol ether (OP-10) 3～6

Initiator ammonium persulfate 1～2

Water 100 then, monomer and emulsifying agent are mixed earlier, add initiator, the controlled polymerization temperature is 70～85 ℃, polymerization time is 4～6h, promptly makes high melting temperature acrylic ester emulsion of the present invention;

Second step: the preparation of frie retardant coating: at first good by aforesaid right requirement 1 described frie retardant coating component concentration weighing, then emulsion and fire proofing additive are put together and mix 20～30 minutes, after sand mill grinds, add expandability expanded graphite, filler and the film coalescence aid of above-mentioned component, promptly get finished product of the present invention after mixing.