JPS6116781B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a fireproof coating for electric wires that forms a strong carbonized layer due to heat during a fire to prevent the spread of fire. In recent years, the use of electrical equipment in high-rise buildings and factories has increased, not only for lighting, but also for power sources and centralized control of operating equipment.As a result, an extremely large amount of electrical wiring is required for energy supply and the transmission and reception of control signals. began to be applied. These electric wires are usually coated with a polymeric material such as polyethylene as a sheath material, but they are extremely flammable and have a major problem in that in the event of a fire, the fire can spread through the wires. For this reason, it is common practice to apply fire retardant paint to coated wires to prevent the spread of fire, and various fire retardant paints have been developed for this purpose, but most of these are solvent-based paints.
Since most painting work is done inside buildings, there is a risk of toxicity to workers, fire hazards due to ignition, etc.
On the other hand, while water-diluted paints do not have the drawbacks of solvent-based paints, they have poor water resistance and also cause large cracks in the fire protection coating when electric wires are bent during installation. easy to do,
In the event of a fire, flames can enter through this part and cause the fire to spread, resulting in a fatal drawback such as the flame-retardant effect being diminished. The present invention solves the above-mentioned problems and provides a fireproof coating for electric wires that has excellent fire resistance, flexibility, and good fire spread prevention properties. Such a paint is made of (1) (a) ammonium polyphosphate and/or having a phosphorus content of approximately 66 to 75% by weight in terms of P ₂ O ₅ and a nitrogen content of approximately 12 to 24% by weight in terms of N; Encapsulated fire spread encapsulated in a mixture of modified ammonium polyphosphate 1.0 to 10.0 parts by weight (b) melamine 0.1 to 10.0 parts by weight (c) starch and/or cellulose 1.0 parts by weight, and (d) dipentaerythritol 1.0 to 10.0 parts by weight inhibitor
It consists of a homogeneous mixture of 84-95% by weight (2) fibrous material 1-15% by weight (3) and rubber latex and/or acrylic emulsion with a solid content of 4-15% by weight. The protective coating of the present invention has the function of the encapsulated fire spread preventive agent forming a strong carbonized layer against flames, and even if cracks occur in the protective coating due to expansion of the wire sheath material due to high heat, it blocks the cracks. Since it has a so-called heat-sealing function, it solves the lack of heat-sealing properties and has extremely high fire spread prevention properties compared to known fire prevention paints. In addition, since the water-soluble components in the fire spread preventive agent contained in the encapsulation are retained in the coating film, the desired fire spread preventive properties are maintained over a long period of time. The above-mentioned components and compounding ratio of the paint of the present invention were determined through extensive experiments, and the reaction mechanism has not yet been elucidated. Sexuality is significantly reduced. Commercially available ammonium polyphosphates and modified polyphosphoric acids can be used, such as Sumisaf L, Sumisaf P (manufactured by Sumitomo Chemical Industries),
Taien S, Taien A (Taihei Kagaku), Gokatsu AF#100 (Nissan Kagaku), Hostik P
#30 (manufactured by Monsanto Chemical) etc. The above ammonium polyphosphate and modified ammonium polyphosphate should have a phosphorus content of 75% by weight or less in terms of P ₂ O ₅ and a nitrogen content of 12% by weight or more in terms of N, in order to improve the fire spread prevention properties of the paint. It is preferable. In other words, the phosphorus content is 75% by weight calculated as P ₂ O ₅ .
As mentioned above, when the nitrogen content is 12% by weight or less in terms of N, the fire spread prevention property deteriorates due to a decrease in the heat sealing property of the coating film. The starch includes potato starch, rice starch, wheat starch, corn starch,
Raw starches such as tapioca starch, soluble starches, oxidized starches, fluid starches, white dextrin, yellow dextrin, British gum starch phosphate, etc. can be used. Examples of the celluloses that can be used include cotton cellulose, wood cellulose, soda cellulose, ethyl cellulose, and carboxymethyl cellulose; organic acid ester cellulose such as cellulose acetate and cellulose propionate; and inorganic acid ester cellulose such as cellulose phosphate and cellulose sulfate. . The encapsulated fire spread preventive agent is added in an amount of 84 to 95% by weight in terms of the encapsulated fire spread preventive agent in the solid content of the paint. If the amount added is less than 84% by weight, effects such as the formation of a strong carbonized layer against fire and heat sealability will not be sufficiently obtained, while even if the amount added is more than 95% by weight, these effects will be further reduced. No increase in effectiveness is observed, and on the contrary, the added amount of fibers and binder decreases, resulting in insufficient properties, which is not preferable. The reason why the fire spread preventive agent is encapsulated in the present invention is that by covering a part of the fire spread preventive agent with an encapsulating agent that is insoluble in water, the fire spread preventive agent is retained in the coating film and the fire spread preventive properties of the paint film are maintained for a long period of time. The goal is to maintain this for a long time. Furthermore, since the fire spread inhibitor of the present invention is effective only when the four components (a) to (d) above coexist, the encapsulated fire spread inhibitor must contain all the components, including melamine, dipentaerythritol, The effects of the present invention cannot be obtained even if water-insoluble or sparingly soluble components are incorporated into the paint without being encapsulated. The fibers are added to make the paint into a mastic state to improve painting workability and adhesion, to prevent cracks in the paint film and to prevent the charred layer formed by flames from falling off, and the amount added is less than 1% by weight. If the amount is too low, these characteristics cannot be obtained, and if it is more than 15% by weight, the paint will become dry and workability will decrease, and the heat sealability and flexibility of the paint film will decrease. Undesirable. Specific examples of the above-mentioned fibers include inorganic fibers and whiskers such as asbestos, silica alumina fibers, glass fibers, silicon carbide fibers, talc fibers, and silicon carbide whiskers, and organic fibers such as vinylon fibers, cellulose fibers, and waste paper pulp. I can do it. The binder for forming the coating film containing the fire spread preventive agent should be one that does not inhibit the heat sealing properties of the fire spread preventive agent and has excellent properties such as adhesion to coated wires, flexibility, and water resistance. use Rubber latexes, acrylic emulsions, and the like can be used as binders having such characteristics. Specific examples of rubber-based latexes include styrene-butadiene-based latex, chloroprene-based latex, isoprene-based latex, methyl methacrylate-butadiene-based latex, carboxy-modified styrene-butadiene-based latex, and natural rubber-based latex. Acrylic emulsions can be synthesized from various monomers, and have a glass transition temperature (Tg) of
is preferably 10°C or less, especially -20°C to -50°C.
℃ is preferred. If the Tg is higher than 10°C, it will not be possible to obtain a coating film with sufficient flexibility, and the coating will crack and easily fall off due to bending during cable installation work or expansion and contraction of the cable due to temperature changes. . On the other hand, those with low Tg make the coating film sticky, but this can be reduced by adding the above-mentioned fibers. Further, even if some tackiness remains in the coating film, there is no particular problem in practical use. For example, it consists of a homopolymer of 2-ethylhexyl acrylate.
Emulsions with Tg -88°C can also be used as binders. An acrylic emulsion that imparts appropriate flexibility to the coating film has a Tg of 0°C to -50.
℃ is particularly preferred. Monomers used in the synthesis of acrylic emulsions include, for example, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate,
Examples include 2-ethylhexyl methacrylate, hydroxyethyl methacrylate, methacrylic acid, acrylic acid, styrene, maleic anhydride, vinyltoluene, vinyl acetate and other α/β-unsaturated carboxylic acid esters. These binders are used in an amount of 4 to 15% by weight on a solid basis. If the amount added is less than 4% by weight, it will not be possible to form a coating film with sufficient adhesion, flexibility, water resistance, etc., while if it is more than 15% by weight, the adhesion and flexibility will be even worse. However, there is no improvement in water resistance, etc., and on the contrary, since the amounts of the fire spread preventive agent and fibrous material added are reduced, the characteristics possessed by these agents cannot be sufficiently obtained. In addition, if necessary, add an appropriate amount of colored pigment to the paint.
Colorants such as dyes can be added. The microencapsulated fire spread inhibitor is obtained by encapsulating a mixture of components (a) to (d) by a known microencapsulation method. Examples of microencapsulation methods that can be used include interfacial polymerization, in situ polymerization, in-liquid curing, phase separation, in-liquid drying, melt-dispersion cooling, spray drying, and powder bed methods. The microencapsulating agent used must have good water resistance and good affinity and adhesion with the aqueous binder. Examples of such microencapsulating agents include vinyl chloride resin, vinylidene chloride resin, epoxy resin, urethane resin, acrylic resin, phenolic resin, vinyl acetate resin, cellulose resin, alkyd resin, shellac resin, diallylphthalate resin, polyamide resin, Melamine resins, urea resins and the like can be used alone or in combination. In addition, the particle size of the microcapsule particles is preferably about 1 to 500 μm; if the particle size is smaller than 1 μm, the proportion of the encapsulating agent in the encapsulated fire spread inhibitor becomes extremely large;
If the size is larger than 500μ, there will be many particles that are not homogeneously encapsulated, making it difficult to maintain fire spread prevention properties over a long period of time, and the capsules may mechanically break when uniformly dispersed in the paint. It becomes easier to do. The coating material of the present invention is produced by roughly kneading the water-based binder and the capsule fire spread prevention agent using a conventional stirrer, such as a butterfly mixer, paddle-type stirrer, propeller-type stirrer, turbine-type stirrer, or reciprocating stirrer. After that, a method can be used in which fibers and, if necessary, a coloring agent are added and kneaded using a mixing machine such as a kneader mixer, internal mixer, Müller mixer, or pony mixer. The paint obtained by uniformly kneading can be diluted with water to an appropriate viscosity if necessary, and applied by methods such as spatula coating, brush coating, and spray coating. The present invention will be explained below with reference to Examples. Each paint used in the examples was prepared by uniformly stirring and mixing the ingredients (parts by weight) shown in Table 1 using a disper.
Fireproof paints of the present invention (Examples 1 to 4) and comparative paints (Comparative Examples 1 to 9) were prepared. In Comparative Examples 1 to 3, the fire spread preventive agent was not encapsulated but was made into a paint. A physical property test of the obtained paint was conducted using a polyethylene sheath material with an outer diameter of 15 mm and a length of 50 cm.
The test was performed on a sample that was coated on a coated wire to a thickness of 1 mm and dried at room temperature for 3 days. The test results are shown in Table 2. CAP-A, CAP-B, CAP-C and CAP were used as encapsulated fire spread inhibitors before the examples.
-J and CAP-D to CAP-I for comparative examples were prepared as follows. CAP-A; dipentaerythritol 640g, melamine 130g
g, wheat starch 430g and ammonium polyphosphate [trade name Sumisaf L, manufactured by Sumitomo Chemical, solid content
Phosphoric acid content (in terms of P ₂ O ₅ ): 66% by weight, nitrogen content (in terms of N)
24% by weight] 1070g was ground and mixed in a mortar to prepare a fire spread preventive agent. A solution prepared by dissolving 100 g of polyvinyl acetate resin in 5000 ml of chloroform is maintained at 40° C., and the above fire spread inhibitor is gradually added to the solution with sufficient stirring to homogeneously disperse it. 5,000 ml of ethanol is gradually added to this dispersion to phase-separate the polyvinyl acetate surrounding the fire spread inhibitor. After gradually cooling to room temperature, the encapsulated material was collected by decantation, washed once with ethanol, collected by centrifugation, and dried to yield 2300 g of encapsulated fire spread inhibitor CAP-
I got an A. CAP-B; dipentaerythritol 100g, melamine 25
g, 41 g of ginger starch, and 123 g of ammonium polyphosphate (dry solidification of the above-mentioned Sumisaf L) were thoroughly ground and mixed to prepare a fire spread preventive agent. 30 g of melamine resin (trade name Sumimaru MC-1 manufactured by Sumitomo Chemical, non-volatile content 80%) is dissolved in 500 ml of ethanol and kept at 40°C. The fire spread preventive agent is gradually added to this solution and stirred thoroughly to form a homogeneous dispersion. Add to this a hardening agent solution (weight ratio of polymerized phosphoric acid/35% hydrochloric acid/methanol = 11.0/
Add 2.5 g of a mixed solution of 19.0/70.0 and stir for 15 minutes, then add 200 ml of n-hexane and 300 ml of toluene.
ml, stirred for 15 minutes, then decanted the liquid phase, washed once with toluene, centrifuged, air-dried to obtain 300 g of encapsulated fire spread inhibitor.
I got CAP-B. CAP-C; dipentaerythritol 350g, melamine 150g
g, starch phosphate 60g and ammonium polyphosphate [trade name Sumisaf P, manufactured by Sumitomo Chemical, solid content
80% by weight dried and solidified. Phosphoric acid content (in terms of P ₂ O ₅ ): 71 to 73% by weight Nitrogen content (in terms of N): 14 to 16% by weight] 420 g was thoroughly ground and mixed to prepare a fire spread preventive agent. Isocyanate resin (product name: Takenate)
D102 Manufactured by Takeda Pharmaceutical, non-volatile content 90% by weight) 50
The fire spread preventive agent is gradually added to a solution prepared by dissolving . After adding 3 g of ethylenediamine to this dispersion and stirring for another 30 minutes, the encapsulated product was separated by decantation, washed once with ethyl acetate, centrifuged, and air-dried to obtain 1010 g of encapsulated fire spread inhibitor CAP-C. . CAP-D: Wheat starch 430g, ammonium polyphosphate (solid content of Sumisafe L) 215g, melamine 430g
Thoroughly pulverize and mix 860g of dipentaerythritol and 860g of dipentaerythritol, use this as a fire spread preventive agent, and encapsulate it in the same manner as CAP-A using 90g of polyvinyl acetate resin to obtain 1970g of encapsulated fire spread preventive agent.
I got CAP-D. CAP-E; Wheat starch 143g, ammonium polyphosphate (solid content of Sumisaf L) 1576g, melamine
Thoroughly grind and mix 143 g and dipentaerythritol 286 g, use this as a fire spread preventive agent, and encapsulate it in the same manner as CAP-A using 100 g of polyvinyl acetate resin to obtain 2180 g of encapsulated fire spread preventive agent.
Obtained CAP-E. CAP-F; 375 g of wheat starch, 19 g of melamine, 750 g of dipentaerythritol, and 1125 g of ammonium polyphosphate (solid content of the above-mentioned Sumisaf L) were thoroughly ground and mixed, and this was used as a fire spread prevention agent, and CAP was prepared using 100 g of polyvinyl acetate resin - 2300g of encapsulated fire spread prevention agent encapsulated in the same manner as A
I got CAP-F. CAP-G: 1000g of wheat starch, 4000g of ammonium polyphosphate (solid content of Sumisafe L above), 5000g of dipentaerythritol and 1100g of melamine are thoroughly ground and mixed, and this is used as a fire spread preventive agent, and CAP is made using 100g of polyvinyl acetate resin. -A was encapsulated in the same manner as in A to obtain 2130 g of encapsulated fire spread inhibitor CAP-G. CAP-H: 137 g of wheat starch, 1100 g of melamine, 69 g of dipentaerythritol, and 963 g of ammonium polyphosphate (the solid content of the above Sumisaf L) were thoroughly ground and mixed, and an isocyanate resin (the above Takenate
D102) encapsulated in the same manner as CAP-C using 110g, and 2310g of encapsulated fire spread prevention agent
I got CAP-H. CAP-I: 100 g of wheat starch, 500 g of melamine, 1100 g of dipentaerythritol, and 500 g of ammonium polyphosphate (solid content of the above Sumisaf L) were thoroughly ground and mixed, and an isocyanate resin (the above Takenate
D102) Using 110g, encapsulate in the same manner as CAP-C and 2240g encapsulated fire spread prevention agent.
I got CAP-I. CAP-J; 130 g of wheat starch, 778 g of melamine, 1167 g of dipentaerythritol, and 195 g of ammonium polyphosphate (the solid content of the above-mentioned Sumisafe P) were thoroughly ground and mixed to make a melamine resin (the above-mentioned Sumimaru MC-J).
1) Using 120g, encapsulate 2310g of encapsulated fire spread inhibitor in the same manner as CAP-B.
I got CAP-J.

【table】

【table】

【table】

[Table] In Table 1, in Comparative Example 4, when ammonium polyphosphate was less than the lower limit of 1.0 parts by weight,
Comparative Example 5 is ammonium polyphosphate, which is the upper limit of 10
If the melamine content is less than the lower limit of 0.1 parts by weight, Comparative Example 6 will be used.
If melamine is more than the upper limit of 10 parts by weight,
Comparative Example 8 shows a case in which dipentaerythritol is smaller than the lower limit of 1.0 parts by weight, and Comparative Example 9 shows a case in which dipentaerythritol is more than 10 parts by weight as an upper limit. It is found that the effects of the present invention cannot be obtained in any of these comparative examples. Example 5 The same paint as in Example 1 was used except that ethyl cellulose was used instead of wheat starch, and the physical properties were tested in the same manner. The flexibility, water resistance, and flame retardant properties were as good as in Example 1, and the foaming ratio was 66. Example 6 The same paint as in Example 3 was used except that cellulose phosphate was used instead of starch phosphate, and the physical properties were tested in the same manner. The flexibility, water resistance, and flame retardant properties were as good as in Example 3, and the expansion ratio was 65.

Claims (1)

[Claims] 1 (1) (a) Phosphoric acid content is approximately 66 to 75% by weight in terms of P ₂ O ₅ , and nitrogen content is approximately 12 to 24% by weight in terms of N.
Ammonium polyphosphate and/or modified ammonium polyphosphate 1.0 to 10.0 parts by weight (b) Melamine 0.1 to 10.0 parts by weight (c) Starch and/or cellulose
1.0 parts by weight (d) Encapsulated fire spread inhibitor containing a mixture of 1.0 to 10.0 parts by weight of dipentaerythritol 84 to 95% by weight (2) Fibrous 1 to 15% by weight and (3) Rubber latex and/or A foaming fireproofing paint for electric wires, comprising a homogeneous mixture of acrylic emulsion with a solid content of 4 to 15% by weight.