JP2019131956A - Steel pipe filled with polyurethane foam - Google Patents

Abstract

To provide a steel pipe with excellent rust preventability and preventing combustion in processing.SOLUTION: A steel pipe 2 is filled with a flame-retardant polyurethane foam 5 containing an urethane resin and a flame retardant.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a steel pipe filled with polyurethane foam.

  Steel pipes are used to install display objects such as signs, traffic lights, electric bulletin boards, etc. on the road or on the side of the road. Although this steel pipe is provided on the road or side of the road with the display attached, there is a problem that condensation of high humidity air occurs inside the steel pipe and rust occurs inside the steel pipe.

  On the other hand, in Patent Document 1, after coating the inner surface of a circular steel pipe with a rust preventive paint mainly composed of moisture-curing urethane resin, the rigid polyurethane foam composition is injected into the circular steel pipe and foamed. Thus, there is disclosed a rust-proofing method for the inner surface of a circular steel pipe, characterized in that air present inside the circular steel pipe is discharged outside the steel pipe and the inside of the circular steel pipe is filled with a rigid polyurethane foam.

Patent No. 5705174

  Even if coating is performed with a rust preventive paint as in Patent Document 1, the steel pipe is in a high humidity condition, so that there is a problem that the coating is easily peeled off due to temperature shrinkage and the durability is poor. In addition, since the inside of the circular steel pipe is filled with a hard polyurethane foam having a different composition after being coated with a rust preventive paint mainly composed of a moisture curable urethane resin, the construction is complicated.

  Further, since the hard polyurethane foam of Patent Document 1 has no heat resistance, when a fire occurs, the hard polyurethane foam filled in the circular steel pipe of Patent Document 1 can be easily melted or burned at high temperature to perform its function. Disappear.

  Furthermore, in the rust prevention treatment method of Patent Document 1, since the hard polyurethane foam does not have heat resistance, it is difficult to heat-process the circular steel pipe after filling the hard polyurethane foam.

  An object of the present invention is to provide a steel pipe excellent in rust resistance, fire resistance and thermal workability.

  The present invention encompasses the subject matter described in the following sections.

  Item 1. A steel pipe filled with a flame retardant polyurethane foam containing a urethane resin and a flame retardant.

  Item 2. The steel pipe according to item 1, wherein the flame-retardant polyurethane foam further contains a trimerization catalyst, and the flame retardant contains red phosphorus.

  Item 3. Item 3. The steel pipe according to Item 1 or 2, wherein the flame-retardant polyurethane foam is in direct contact with the inner peripheral surface of the steel pipe.

  Item 4. The flame retardant comprises at least one flame retardant selected from the group consisting of phosphate-containing flame retardants, phosphate esters, bromine-containing flame retardants, metal hydroxides, needle fillers, and boron-containing flame retardants, The addition amount of the red phosphorus is in the range of 1 to 30 parts by mass with respect to 100 parts by mass of the urethane resin, and the addition amount of the at least one flame retardant is 1 to 70 with respect to 100 parts by mass of the urethane resin. Item 3. The steel pipe according to Item 2, which is a range of parts by mass.

  According to the present invention, durability and productivity of a steel pipe can be improved.

(A) Schematic diagram of the steel pipe of the embodiment of the present invention, (B) A cross-sectional view taken along line BB of FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1A is a schematic view of a steel pipe 1 with a road sign. The end of the circular steel pipe 2 is attached to the ground, for example, a road or a roadside. One or a plurality (two in the figure) of steel pipes 3 having a smaller diameter than the circular steel pipe 2 are attached to the distal end portion of the circular steel pipe 2 so as to extend substantially perpendicular to the circular steel pipe 2. A guide sign 4 as a road sign is attached to the end of the steel pipe 3 opposite to the side attached to the circular steel pipe 2.

  As shown in FIG. 1 (B), the internal space of the circular steel pipe 2 is filled with a flame retardant urethane foam 5. The flame retardant urethane foam 5 is obtained by filling the internal space of the circular steel pipe 2 with the flame retardant urethane resin composition, and foaming and curing. The flame retardant urethane resin composition will be described later. The flame retardant urethane foam 5 is in direct contact with the inner peripheral surface of the circular steel pipe 2. Preferably, the flame retardant urethane foam 5 is in direct contact with 80% or more, more preferably 90% or more, of the total inner surface of the circular steel pipe 2. In this case, since the flame retardant urethane foam 5 is in contact with the inner peripheral surface of the circular steel pipe 2, the amount of high-humidity air that comes into contact with the inner peripheral surface of the circular steel pipe 2 is suppressed. improves.

  Moreover, it is preferable that the flame-retardant urethane foam 5 occupies 80% or more of the entire volume of the internal space of the circular steel pipe 2, and preferably 90% or more. Also in this case, since the flame retardant urethane foam 5 occupies most of the internal space of the circular steel pipe 2, the amount of high-humidity air that enters the internal space of the circular steel pipe 2 is suppressed, so that the rust resistance is achieved. Will improve. Therefore, the durability of the circular steel pipe 2 is also improved.

  Furthermore, the flame-retardant polyurethane foam 5 used in the present embodiment is resistant to heat such as fire, and forms a fireproof heat insulating layer by heating. For this reason, for example, even if the road-signed steel pipe 1 encounters a fire, the combustion residue of the flame-retardant polyurethane foam 5 retains its shape, so that it is compared with a case where a conventional polyurethane foam without fire resistance is filled. The deformation of the steel pipe 1 with a road sign due to heat can be prevented for a long time.

Furthermore, since the flame retardant polyurethane foam 5 used in the present embodiment is resistant to heat such as fire, it can withstand thermal processing such as cutting or welding.
For example, the cutting can be performed by gas fusing using acetylene gas at a temperature of 700 to 1,500 ° C. Welding can be performed by arc welding or the like at a temperature of 1,500 to 2,800 ° C.

  Therefore, the circular steel pipe 2 filled with the flame retardant polyurethane foam 5 can be cut to an arbitrary length, or the end portions of the two round steel pipes 2 filled with the flame retardant polyurethane foam 5 inside. They can be welded together using a flange joint or the like.

  Thus, according to the structure of the circular steel pipe 2 which filled the flame-retardant polyurethane foam 5 of this embodiment inside, heat workability increases.

  Unlike the conventional case, since the circular steel pipe 2 can be filled before the thermal processing of the circular steel pipe 2, the manufacturing of the circular steel pipe 2 becomes flexible and the productivity is improved.

  Here, the flame retardant urethane resin composition used for the production of the flame retardant polyurethane foam 5 will be described.

  The flame retardant urethane resin composition contains a urethane resin and a flame retardant.

  Examples of the urethane resin include those containing a polyisocyanate compound as a main agent and a polyol compound as a curing agent.

  Examples of the polyisocyanate compound that is a main component of the urethane resin include aromatic polyisocyanates, alicyclic polyisocyanates, and aliphatic polyisocyanates.

  Examples of the aromatic polyisocyanate include phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, dimethyldiphenylmethane diisocyanate, triphenylmethane triisocyanate, naphthalene diisocyanate, polymethylene polyphenyl polyisocyanate, and the like.

  Examples of the alicyclic polyisocyanate include cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and dimethyldicyclohexylmethane diisocyanate.

  Examples of the aliphatic polyisocyanate include methylene diisocyanate, ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate, and hexamethylene diisocyanate.

  One or more polyisocyanate compounds can be used.

  The main component of the urethane resin is preferably diphenylmethane diisocyanate for reasons such as ease of use and availability.

  One or two or more polyisocyanate compounds can be used.

  Examples of the polyol compound include polylactone polyol, polycarbonate polyol, aromatic polyol, alicyclic polyol, aliphatic polyol, polyester polyol, polymer polyol, and polyether polyol.

  Examples of the polylactone polyol include polypropiolactone glycol, polycaprolactone glycol, and polyvalerolactone glycol.

  Examples of the polycarbonate polyol include a polyol obtained by a dealcoholization reaction of a hydroxyl group-containing compound such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, octanediol, and nonanediol with diethylene carbonate, dipropylene carbonate, and the like. Etc.

  Examples of the aromatic polyol include bisphenol A, bisphenol F, phenol novolac, and cresol novolak.

  Examples of the alicyclic polyol include cyclohexanediol, methylcyclohexanediol, isophoronediol, dicyclohexylmethanediol, dimethyldicyclohexylmethanediol, and the like.

  Examples of the aliphatic polyol include ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol.

  Examples of the polyester polyol include a polymer obtained by dehydration condensation of a polybasic acid and a polyhydric alcohol, a polymer obtained by ring-opening polymerization of a lactone such as ε-caprolactone and α-methyl-ε-caprolactone, Examples thereof include condensates of hydroxycarboxylic acid and the above polyhydric alcohol.

  Specific examples of the polybasic acid include adipic acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid, and succinic acid.

  Specific examples of the polyhydric alcohol include bisphenol A, ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, diethylene glycol, 1,6-hexane glycol, neopentyl glycol, and the like. .

  Specific examples of the hydroxycarboxylic acid include castor oil, a reaction product of castor oil and ethylene glycol, and the like.

  As the polymer polyol, for example, an ethylenically unsaturated compound such as acrylonitrile, styrene, methyl acrylate, and methacrylate is graft-polymerized to an aromatic polyol, an alicyclic polyol, an aliphatic polyol, a polyester polyol, a polyether polyol, and the like. Examples thereof include polymers, polybutadiene polyols, modified polyols of polyhydric alcohols, and hydrogenated products thereof.

  Examples of the modified polyol of the polyhydric alcohol include those modified by reacting the raw material polyhydric alcohol with an alkylene oxide.

Examples of the polyhydric alcohol include trihydric alcohols such as glycerin and trimethylolpropane;
Tetravalent to octavalent alcohols such as pentaerythritol, sorbitol, mannitol, sorbitan, diglycerin, dipentaerythritol and the like, sucrose, glucose, mannose, fructose, methylglucoside and derivatives thereof;
Phenol, phloroglucin, cresol, pyrogallol, catechol, hydroquinone, bisphenol A, bisphenol F, bisphenol S, 1-hydroxynaphthalene, 1,3,6,8-tetrahydroxynaphthalene, anthrol, 1,4,5 Phenols such as 1,8-tetrahydroxyanthracene and 1-hydroxypyrene;
Polybutadiene polyol;
Castor oil polyol;
Examples include (co) polymers of hydroxyalkyl (meth) acrylates and polyfunctional (eg, 2 to 100 functional group) polyols such as polyvinyl alcohol, and condensates (novolaks) of phenol and formaldehyde.

  The method for modifying the polyhydric alcohol is not particularly limited, but a method of adding alkylene oxide (hereinafter abbreviated as AO) is preferably used.

  As AO, C2-C6 AO, for example, ethylene oxide (hereinafter abbreviated as EO), 1,2-propylene oxide (hereinafter abbreviated as PO), 1,3-propyloxide, 1,2- Examples include butylene oxide and 1,4-butylene oxide. Among these, PO, EO, and 1,2-butylene oxide are preferable from the viewpoint of properties and reactivity, and PO and EO are more preferable.

  When two or more types of AO are used (for example, PO and EO), block addition or random addition may be used, or a combination thereof may be used.

  As the polyether polyol, for example, in the presence of at least one low molecular weight active hydrogen compound having two or more active hydrogens, at least one alkylene oxide such as ethylene oxide, propylene oxide, and tetrahydrofuran is subjected to ring-opening polymerization. The obtained polymer is mentioned.

  Examples of the low molecular weight active hydrogen compound having two or more active hydrogens include diols such as bisphenol A, ethylene glycol, propylene glycol, butylene glycol, and 1,6-hexanediol; triols such as glycerin and trimethylolpropane; Examples include amines such as ethylenediamine and butylenediamine.

  As the polyol, it is preferable to use a polyester polyol or a polyether polyol, and a polyester polyol is more preferable because a polyurethane foam obtained by curing the flame retardant urethane resin composition is difficult to ignite.

  Next, the compounding ratio of the main component of urethane resin and the curing agent will be described.

  In the present invention, the index is defined by [number of equivalents of isocyanate] × 100 ÷ [number of equivalents of polyol + number of equivalents of water].

  Here, the number of equivalents of the isocyanate compound is represented by [weight of isocyanate compound (g)] × [content of isocyanate group in isocyanate compound (%)] ÷ 100 ÷ [molecular weight of isocyanate group].

  The number of equivalents of the polyol compound is represented by [hydroxyl value of the polyol compound (mgKOH / g)] × [weight of the polyol compound (g)] ÷ [molecular weight of potassium hydroxide].

  The equivalent number of water is represented by [weight of water (g)] × 2 ÷ [molecular weight of water].

  The range of the index is not particularly limited, but is preferably in the range of 100 to 1000, more preferably 120 to 700, still more preferably 150 to 500, and most preferably 250 to 400. Yes.

  When the equivalent ratio is 100 or more, good heat resistance can be obtained, and when the equivalent ratio is 1000 or less, foaming failure can be prevented.

  The flame retardant urethane resin composition can contain a urethane resin curing catalyst in addition to the urethane resin.

  Examples of the urethane curing catalyst include amino compounds, tin compounds, and acetylacetone metal salts.

  Examples of the amino compound include pentamethyldiethylenetriamine, triethylamine, N-methylmorpholine bis (2-dimethylaminoethyl) ether, bis (2-dimethylaminoethyl) ether, N, N, N ′, N ″, N ″ — Pentamethyldiethylenetriamine, N, N, N′-trimethylaminoethyl-ethanolamine, bis (2-dimethylaminoethyl) ether, N-methyl-N′-dimethylaminoethylpiperazine, secondary amine functional group in imidazole ring Is substituted with a cyanoethyl group, N, N-dimethylcyclohexylamine, diazabicycloundecene, triethylenediamine, tetramethylhexamethylenediamine, N-methylimidazole, trimethylaminoethylpiperazine, tripropylamido , Tetramethylammonium salts, tetraethylammonium salts, triphenyl ammonium salts.

  Examples of the tin compound include stannous octylate, dibutyltin diacetate, dibutyltin dilaurate, and the like.

  Examples of the acetylacetone metal salt include acetylacetone aluminum, acetylacetone iron, acetylacetone copper, acetylacetone zinc, acetylacetone beryllium, acetylacetone chromium, acetylacetone indium, acetylacetone manganese, acetylacetone molybdenum, acetylacetone titanium, acetylacetone cobalt, acetylacetone vanadium, and acetylacetone zirconium. .

  One or two or more urethane resin curing catalysts can be used.

  Although it does not specifically limit to the addition amount of the urethane resin curing catalyst used for the flame-retardant urethane resin composition which concerns on this invention, 0.01-10 with respect to 100 mass parts of urethane resins which consist of a polyisocyanate compound and a polyol compound. It is preferably in the range of parts by mass, more preferably in the range of 0.01 to 8 parts by mass, still more preferably in the range of 0.01 to 6 parts by mass, and 0.01 to 1.5 parts by mass. Most preferred is the range of parts. In the case of 0.01 parts by mass or more and 10 parts by mass or less, it is easy to handle and control of the reaction is easy.

The flame retardant urethane resin composition can contain a trimerization catalyst. The trimerization catalyst reacts the isocyanate group contained in the polyisocyanate compound, which is the main component of the polyurethane resin, to trimerize and promote the formation of an isocyanurate ring. As aromatic compounds such as tris (dimethylaminomethyl) phenol, 2,4-bis (dimethylaminomethyl) phenol, 2,4,6-tris (dialkylaminoalkyl) hexahydro-S-triazine, potassium acetate, sodium acetate , Quaternary ammonium compounds such as potassium 2-ethylhexanoate, sodium 2-ethylhexanoate, carboxylates of tertiary amines, amine compounds such as aziridines such as 2-ethylaziridine, diazabicycloundecene, Lead compounds such as lead naphthenate and lead octylate, An alcoholate compound such as thorium methoxide, a phenolate compound such as potassium phenoxide, a quaternary ammonium salt of carboxylic acid, or the like may be used.

  The addition amount of the trimerization catalyst used in the flame-retardant urethane resin composition according to the present invention is not particularly limited, but is preferably in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the urethane resin. The range is more preferably 0.01 to 8 parts by mass, still more preferably 0.01 to 6 parts by mass, and most preferably 0.5 to 1.5 parts by mass.

  When the amount is 0.01 parts by mass or more, the problem that the trimerization of isocyanate is inhibited does not occur, and when the amount is 10 parts by mass or less, the problem that the urethane bond is inhibited can be reduced.

  One or two or more trimerization catalysts can be used.

  Moreover, a flame-retardant urethane resin composition can contain a foaming agent. The foaming agent promotes foaming of the urethane resin.

Examples of the foaming agent include water;
Low boiling point hydrocarbons such as propane, butane, pentane, hexane, heptane, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane;
Chlorinated aliphatic hydrocarbon compounds such as dichloroethane, propyl chloride, isopropyl chloride, butyl chloride, isobutyl chloride, pentyl chloride, isopentyl chloride;
Fluorine compounds such as trichloromonofluoromethane, trichlorotrifluoroethane, CHF ₃ , CH ₂ F ₂ and CH ₃ F;
Hydrochlorofluorocarbon compounds such as dichloromonofluoroethane (for example, HCFC141b (1,1-dichloro-1-fluoroethane), HCFC22 (chlorodifluoromethane), HCFC142b (1-chloro-1,1-difluoroethane);
Hydrofluorocarbon compounds such as HFC-245fa (1, 1, 1, 3, 3-pentafluoropropane), HFC-365mfc (1, 1, 1, 3, 3-pentafluorobutane);
Hydrofluoroolefins such as HFO-1233zd (E) (trans-1-chloro-3,3,3-trifluoropropene), HFO-1234yf (2,3,3,3-tetrafluoro-1-propene);
Organic physical foaming agents such as ether compounds such as diisopropyl ether, or mixtures of these compounds;
Examples include inorganic physical foaming agents such as nitrogen gas, oxygen gas, argon gas, and carbon dioxide gas.

  The foaming agent is preferably water, cyclopentane, hydrofluorocarbon or hydrofluoroolefin, and more preferably water and hydrofluorocarbon or hydrofluoroolefin are used in combination.

  One or two or more foaming agents can be used.

  Although the addition amount of the foaming agent used for the flame-retardant urethane resin composition according to the present invention is not particularly limited, it is preferably in the range of 0.1 to 20 parts by mass with respect to 100 parts by mass of the urethane resin. More preferably, it is in the range of 5 to 15 parts by mass, still more preferably in the range of 1 to 15 parts by mass, and most preferably in the range of 1.5 to 10 parts by mass.

  When the water range is 0.1 parts by mass or more, foaming is promoted, and the density of the obtained molded product can be reduced. When the water content is 20 parts by mass or less, the cells are continuous with each other in the obtained molded product. Can be introduced.

  The flame retardant urethane resin composition can contain a foam stabilizer.

  Examples of the foam stabilizer include surfactants such as a polyoxyalkylene foam stabilizer such as polyoxyalkylene alkyl ether and a silicone foam stabilizer such as organopolysiloxane.

  The amount of the foam stabilizer used for the urethane resin cured by the chemical reaction is appropriately set depending on the urethane resin cured by the chemical reaction to be used. For example, for 100 parts by mass of the urethane resin, It is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 4 parts by mass, and still more preferably 1 to 3 parts by mass.

  One or more foam stabilizers can be used.

  Next, the flame retardant added to the flame retardant urethane resin composition will be described.

  The flame retardant includes red phosphorus and at least one selected from the group consisting of phosphate-containing flame retardants, phosphate esters, bromine-containing flame retardants, metal hydroxides, needle fillers, and boron-containing flame retardants. .

  First, red phosphorus will be described. There is no limitation to red phosphorus, and a commercially available product can be appropriately selected and used. The addition amount of red phosphorus used in the flame retardant urethane resin composition is in the range of 1 to 30 parts by mass with respect to 100 parts by mass of the urethane resin composed of the compound and the polyol compound. The amount of red phosphorus added is preferably in the range of 3.2 to 20 parts by weight, more preferably in the range of 3.2 to 18 parts by weight, and still more preferably in the range of 6 to 18 parts by weight. .

  When the range of red phosphorus is 1 part by mass or more, the self-extinguishing property of the flame retardant urethane resin composition is maintained, and when it is 30 parts by mass or less, foaming of the flame retardant urethane resin composition is not inhibited.

  In addition to the red phosphorus described above as a flame retardant, the flame retardant urethane resin composition is a phosphate-containing flame retardant, phosphate ester, bromine-containing flame retardant, metal hydroxide, needle filler and boron-containing flame retardant. At least two selected from the group consisting of flame retardants can be used.

  The phosphoric acid used for the phosphate-containing flame retardant is not particularly limited, and examples thereof include various phosphoric acids such as monophosphoric acid and pyrophosphoric acid.

  Examples of the phosphate-containing flame retardant include phosphorus composed of salts of various phosphoric acids and at least one metal or compound selected from metals of Group IA to IVB of the periodic table, ammonia, aliphatic amines, and aromatic amines. There may be mentioned acid salts. Examples of the metals of Group IA to IVB of the periodic table include lithium, sodium, calcium, barium, iron (II), iron (III), and aluminum.

  Examples of the aliphatic amine include methylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, piperazine and the like.

  Aromatic amines include pyridine, triazine, melamine, ammonium and the like.

  The phosphate-containing flame retardant may be subjected to a known water resistance improving treatment such as silane coupling agent treatment or coating with a melamine resin, and a known foaming aid such as melamine or pentaerythritol may be added. May be.

  Specific examples of the phosphate-containing flame retardant include monophosphate and pyrophosphate.

Although it does not specifically limit as monophosphate, For example, ammonium salts, such as ammonium phosphate, ammonium dihydrogen phosphate, hydrogen diammonium phosphate;
Sodium salts such as monosodium phosphate, disodium phosphate, trisodium phosphate, monosodium phosphite, disodium phosphite, sodium hypophosphite;
Potassium salts such as monopotassium phosphate, dipotassium phosphate, tripotassium phosphate, monopotassium phosphite, dipotassium phosphite, potassium hypophosphite;
Lithium salts such as monolithium phosphate, dilithium phosphate, trilithium phosphate, monolithium phosphite, dilithium phosphite, lithium hypophosphite;
Barium salts such as barium dihydrogen phosphate, barium hydrogen phosphate, tribarium phosphate, barium hypophosphite;
Magnesium salts such as magnesium monohydrogen phosphate, magnesium hydrogen phosphate, trimagnesium phosphate, magnesium hypophosphite;
Calcium salts such as calcium dihydrogen phosphate, calcium hydrogen phosphate, tricalcium phosphate, calcium hypophosphite;
Zinc salts such as zinc phosphate, zinc phosphite, zinc hypophosphite;
Examples thereof include aluminum salts such as primary aluminum phosphate, secondary aluminum phosphate, tertiary aluminum phosphate, aluminum phosphite, and aluminum hypophosphite.

  Among these, since the self-extinguishing property of the phosphate-containing flame retardant is improved, it is preferable to use a monophosphate, and ammonium dihydrogen phosphate, diammonium hydrogen phosphate, primary aluminum phosphate, monophosphate It is more preferable to use at least one selected from the group consisting of sodium and tertiary aluminum phosphate, and it is more preferable to use ammonium dihydrogen phosphate and primary aluminum phosphate. One or two or more monophosphate-containing flame retardants can be used.

  It is preferable that the addition amount of a phosphate containing flame retardant is the range of 1.5-20 mass parts with respect to 100 mass parts of urethane resins. The addition amount of the phosphate-containing flame retardant is more preferably in the range of 1.5 to 10 parts by mass, further preferably in the range of 3 to 10 parts by mass, and in the range of 3 to 8 parts by mass. Most preferred.

  When the range of the phosphate-containing flame retardant is 1.5 parts by mass or more, the self-extinguishing property of the flame retardant urethane resin composition is maintained. When the range of the phosphate-containing flame retardant is 20 parts by mass or less, foaming of the flame retardant urethane resin composition is not inhibited.

  The flame retardant urethane resin composition comprises a phosphate ester, a bromine-containing flame retardant, a metal hydroxide, an acicular filler, and a phosphate-containing flame retardant as a flame retardant instead of or in place of a phosphate-containing flame retardant. At least one selected from the group consisting of boron-containing flame retardants can be used.

  Although it does not specifically limit as phosphate ester, It is preferable to use monophosphate ester, condensed phosphate ester, etc.

  Examples of monophosphate esters include, but are not limited to, trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri (2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris (Isopropylphenyl) phosphate, tris (phenylphenyl) phosphate, trinaphthyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, diphenyl (2-ethylhexyl) phosphate, di (isopropylphenyl) phenyl phosphate, monoisodecyl phosphate, 2 -Acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid Sulfate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, melamine phosphate, dimelamine phosphate, melamine pyrophosphate, triphenylphosphine oxide, tricresylphosphine oxide, diphenyl methanephosphonate, phenylphosphonic acid Examples include diethyl, resilsinol bis (diphenyl phosphate), bisphenol A bis (diphenyl phosphate), phosphaphenanthrene, tris (β-chloropropyl) phosphate, and the like.

  Although it does not specifically limit as condensed phosphate ester, For example, a trialkyl polyphosphate, a resorcinol polyphenyl phosphate, a resorcinol poly (di-2, 6- xylyl) phosphate (the Daihachi Chemical Industry make, brand name PX-200) , Hydroquinone poly (2,6-xylyl) phosphate and condensed phosphates such as condensates thereof.

  Examples of commercially available condensed phosphate esters include resorcinol polyphenyl phosphate (trade name CR-733S), bisphenol A polycresyl phosphate (trade name CR-741), aromatic condensed phosphate ester (trade name CR747), and resorcinol. Examples thereof include polyphenyl phosphate (manufactured by ADEKA, trade name ADK STAB PFR), bisphenol A polycresyl phosphate (trade names FP-600, FP-700), and the like.

  Among these, it is preferable to use a monophosphate ester because the effect of reducing the viscosity in the composition before curing and the effect of reducing the initial calorific value are high, and tris (β-chloropropyl) phosphate is used. Is more preferable.

  Phosphoric acid ester can use 1 type, or 2 or more types.

  The addition amount of the phosphate ester is preferably in the range of 2.5 to 50 parts by mass with respect to 100 parts by mass of the urethane resin. The addition amount of the phosphate ester is more preferably in the range of 3 to 50 parts by mass, further preferably in the range of 3 to 30 parts by mass, and most preferably in the range of 7 to 30 parts by mass.

  When the range of the phosphate ester is 2.5 parts by mass or more, the molded body made of the flame retardant urethane resin composition is difficult to ignite. When the range of the phosphate ester is 50 parts by mass or less, foaming of the flame retardant urethane resin composition is not inhibited.

  Although it will not specifically limit as a bromine containing flame retardant if it is a compound which contains bromine in molecular structure, For example, an aromatic brominated compound etc. can be mentioned.

Specific examples of aromatic brominated compounds include, for example, hexabromobenzene, pentabromotoluene, hexabromobiphenyl, decabromobiphenyl, hexabromocyclodecane, decabromodiphenyl ether, octabromodiphenyl ether, hexabromodiphenyl ether, bis (pentabromo Monomeric organic bromine compounds such as phenoxy) ethane, ethylene-bis (tetrabromophthalimide), tetrabromobisphenol A;
Brominated polycarbonates such as polycarbonate oligomers produced from brominated bisphenol A as a raw material, copolymers of polycarbonate oligomers and bisphenol A;
Brominated epoxy compounds such as diepoxy compounds produced by reaction of brominated bisphenol A with epichlorohydrin, monoepoxy compounds obtained by reaction of brominated phenols with epichlorohydrin;
Poly (brominated benzyl acrylate);
Brominated polyphenylene ether;
Condensates of brominated bisphenol A, cyanuric chloride and brominated phenol;
Brominated polystyrene such as brominated (polystyrene), poly (brominated styrene), cross-linked brominated polystyrene;
Halogenated bromine compound polymers such as crosslinked or non-crosslinked brominated poly (-methylstyrene).

  From the viewpoint of enhancing the self-extinguishing property of the flame retardant urethane resin composition, a brominated aromatic ring-containing aromatic compound in which a bromine atom is substituted on the aromatic ring is preferable, brominated polystyrene, hexabromobenzene and the like are more preferable, and hexabromo More preferred is benzene.

  One or more bromine-containing flame retardants can be used.

  Although it does not specifically limit to the addition amount of a bromine containing flame retardant, It is preferable that it is the range of 1.5-20 mass parts with respect to 100 mass parts of urethane resins. The addition amount of the bromine-containing flame retardant is more preferably in the range of 1.5 to 10 parts by mass, further preferably in the range of 3 to 10 parts by mass, and most preferably in the range of 3 to 8 parts by mass. .

  When the range of the bromine-containing flame retardant is 1.5 parts by mass or more, the self-extinguishing property of the flame retardant urethane resin composition is maintained. When the range of the bromine-containing flame retardant is 20 parts by mass or less, foaming of the flame retardant urethane resin composition is not inhibited.

  Examples of the metal hydroxide include aluminum hydroxide, magnesium hydroxide, dawsonite, calcium aluminate, dihydrate gypsum, calcium hydroxide and the like.

  As the metal hydroxide, it is preferable to use aluminum hydroxide or magnesium hydroxide because of its high fire resistance.

  One or two or more metal hydroxides can be used.

  Although it does not specifically limit to the addition amount of a metal hydroxide, It is preferable that it is the range of 1.5-20 mass parts with respect to 100 mass parts of urethane resins. The addition amount of the metal hydroxide is more preferably in the range of 1.5 to 10 parts by mass, further preferably in the range of 3 to 10 parts by mass, and most preferably in the range of 3 to 8 parts by mass. .

  When the range of the metal hydroxide is 1.5 parts by mass or more, the self-extinguishing property of the flame retardant urethane resin composition is maintained. When the range of the metal hydroxide is 20 parts by mass or less, foaming of the flame retardant urethane resin composition is not inhibited.

  Examples of the acicular filler include potassium titanate whisker, aluminum borate whisker, magnesium-containing whisker, silicon-containing whisker, wollastonite, sepiolite, zonolite, elastadite, boehmite, rod-like hydroxyapatite, glass fiber, asbestos fiber, carbon fiber Graphite fiber, metal fiber, slag fiber, gypsum fiber, silica fiber, alumina fiber, silica / alumina fiber, zirconia fiber, boron nitride fiber, boron fiber, stainless steel fiber and the like.

  The aspect ratio (length / diameter) of the acicular filler is preferably in the range of 5 to 50, more preferably in the range of 10 to 40.

  One or two or more acicular fillers can be used.

  Although it does not specifically limit to the addition amount of an acicular filler, It is preferable that it is the range of 3-30 mass parts with respect to 100 mass parts of urethane resins, It is more preferable that it is the range of 3-20 mass parts, More preferably, it is in the range of 18 parts by mass, and most preferably in the range of 6 to 18 parts by mass.

  When the range of the acicular filler is 3 parts by mass or more, the shape after combustion of the molded body of the flame retardant urethane resin composition containing the flame retardant used in the present invention is maintained. When the range of the acicular filler is 30 parts by mass or less, foaming of the flame retardant urethane resin composition containing the flame retardant used in the present invention is not inhibited.

  Examples of the boron-containing flame retardant include borax, boron oxide, boric acid, and borate.

  Examples of the boron oxide include diboron trioxide, boron trioxide, diboron dioxide, tetraboron trioxide, and tetraboron pentoxide.

  Examples of the borate include alkali metals, alkaline earth metals, elements of Group 4, Group 12, and Group 13 of the periodic table, and ammonium borate.

  Specifically, alkali metal borate such as lithium borate, sodium borate, potassium borate, cesium borate, alkaline earth metal borate such as magnesium borate, calcium borate, barium borate, boron Examples thereof include zirconium acid, zinc borate, aluminum borate, and ammonium borate.

  The boron-containing flame retardant used in the present invention is preferably a borate, and more preferably zinc borate.

  One or more boron-containing flame retardants can be used.

  The addition amount of the boron-containing flame retardant used in the present invention is not particularly limited, but is preferably 0.1 to 60 parts by mass with respect to 100 parts by mass of the urethane resin.

  When the range of the boron-containing flame retardant is 0.1 part by mass or more, the self-extinguishing property of the flame retardant urethane resin composition according to the present invention is maintained. When the range of the boron-containing flame retardant is 60 parts by mass or less, foaming of the flame retardant urethane resin composition according to the present invention is not inhibited.

  At least one selected from the group consisting of a phosphate-containing flame retardant, a phosphate ester, a bromine-containing flame retardant, a metal hydroxide, an acicular filler, and a boron-containing flame retardant is each for 100 parts by mass of the urethane resin. The boron-containing flame retardant is preferably in the range of 0.6 to 60 parts by mass with respect to 100 parts by mass of the urethane resin. In one embodiment, the total amount of phosphate-containing flame retardant, phosphate ester, bromine-containing flame retardant, metal hydroxide, needle filler and boron-containing flame retardant is 9 parts by mass to 200 parts by mass, A more preferable total amount is 10 parts by mass to 50 parts by mass. Moreover, a more preferable upper limit is 40 mass parts, 30 mass parts, 25 mass parts, or 20 mass parts, and a more preferable lower limit is 15 mass parts.

  As a flame retardant other than the above-mentioned red phosphorus, it is preferable to use a phosphate ester, a bromine-containing flame retardant, an acicular filler, and a boron-containing flame retardant, and use a phosphate ester, an acicular filler, and a boron-containing flame retardant. It is more preferable to use a phosphate ester in combination with a needle-like filler and / or a boron-containing flame retardant, and it is most preferable to use a phosphate ester, a needle-like filler and a boron-containing flame retardant in combination.

  The flame retardant urethane resin composition can contain an inorganic filler.

  The inorganic filler is not particularly limited. For example, silica, diatomaceous earth, alumina, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, ferrites, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, base Magnesium carbonate, calcium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, dosonite, hydrotalcite, potassium sulfate such as calcium sulfate, barium sulfate, calcium silicate, talc, clay, mica, montmorillonite, bentonite, activated clay, imogolite , Sericite, glass beads, silica-based balun, aluminum nitride, boron nitride, silicon nitride, carbon black, graphite, carbon balun, charcoal powder, various metal powders, magnesium sulfate, lead zirconate titanate, aluminum Borate, molybdenum sulfide, silicon carbide, various magnetic powder, fly ash, inorganic phosphorus compounds, and the like.

  One or two or more inorganic fillers can be used.

  Furthermore, the flame retardant urethane resin composition is within a range that does not impair the object of the present invention, as necessary, such as phenol-based, amine-based, sulfur-based antioxidants, heat stabilizers, metal harm-preventing agents, charging agents. Additives such as inhibitors, stabilizers, crosslinking agents, lubricants, softeners, pigments, tackifying resins, and tackifiers such as polybutenes and petroleum resins can be included.

  Since the flame retardant urethane resin composition reacts and cures, its viscosity changes over time. Therefore, before using the flame retardant urethane resin composition, the flame retardant urethane resin composition is divided into two or more to prevent the flame retardant urethane resin composition from reacting and curing. And when using a urethane resin composition, a flame-retardant urethane resin composition is obtained by putting together the flame-retardant urethane resin composition divided | segmented into two or more.

  In addition, when dividing the flame retardant urethane resin composition into two or more, each component of the flame retardant urethane resin composition divided into two or more does not start to cure, and each of the flame retardant urethane resin composition Each component may be divided so that the curing reaction starts after the components are mixed.

  The flame retardant urethane resin composition is mixed with each component of the flame retardant urethane resin composition. The flame retardant urethane resin composition is suspended in an organic solvent. Or by dispersing in a solvent to prepare a slurry.

  Alternatively, the main component and the curing agent of the urethane resin can be kneaded separately with a filler or the like and kneaded with a mixer or the like immediately before injection. Further, the components of the flame retardant urethane resin composition excluding the catalyst and the catalyst can be kneaded in the same manner immediately before injection.

  The method of injecting or filling the flame retardant urethane resin composition is not particularly limited. For example, it is stirred using an arbitrary apparatus such as a low pressure foaming machine or a high pressure foaming machine usually used for foaming urethane, a nozzle, etc. May be used for direct injection or filling, or once poured into a cup may be poured before curing. Even when the apparatus does not foam, the injection method is not particularly limited. For example, there is a method in which a mechanical stirrer is used and the agitated material is poured manually in a cup.

  The flame-retardant urethane resin composition can be obtained by the method described above.

  When each component of the flame retardant urethane resin composition is mixed, the reaction starts, the viscosity increases with time, and the fluidity is lost. By injecting the flame retardant urethane resin composition into a mold and curing and molding, a fireproof heat insulating layer made of the flame retardant urethane resin composition can be obtained.

  The specific gravity of the flame retardant urethane resin composition and the flame retardant urethane foam formed therefrom is not particularly limited, but is preferably in the range of 0.02 to 0.2, in the range of 0.02 to 0.1. The range of 0.03 to 0.08 is more preferable, and the range of 0.03 to 0.06 is most preferable.

  The fireproof heat insulating layer obtained by curing the flame retardant urethane resin composition is made of polyurethane foam and has bubbles inside. It is preferable that the air bubbles are independent air bubbles in the polyurethane foam.

The density of the flame retardant urethane resin composition and the flame retardant urethane foam formed therefrom is not particularly limited, but is preferably 10 to 100 kg / m ³ . Such a flame retardant urethane resin composition and a flame retardant urethane foam are lightweight and easy to handle.

  Up to this point, the embodiment of the present invention has been described as an example. However, the present invention is not limited to this, and various modifications as described below are possible.

  The cross-sectional shape of the steel pipe is not limited, and the cross-sectional shape of the circular steel pipe 2 may be rectangular other than circular.

  In addition to the guide sign 4, the road sign may be a guide sign, a warning sign, a regulation sign, an instruction sign, or an auxiliary sign. The sign is not limited to a road sign, and may be any sign that gives information to an observer.

  Although the said embodiment was taken as the example in which the steel pipe 1 is attached to a road sign, the use of the steel pipe 1 is not specifically limited, The steel pipe 1 may be attached to display objects other than a road sign, such as a traffic light and an electric bulletin board. However, it may be used for an indoor or outdoor structure that does not include a display object.

  Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

1. Production of Flame Retardant Polyurethane Foam Flame retardant urethane resin compositions according to Example 1 and Comparative Example 1 were prepared according to the formulation shown in Table 1. The details of each component shown in Table 1 are as follows. The unit is part by mass unless otherwise specified.

(A) Polyol compound A-1: p-phthalic acid-based polyester polyol (manufactured by Kawasaki Kasei Kogyo Co., Ltd., product name: Maximol RFK-505, hydroxyl value: 250 mgKOH / g, number of functional groups: 2 [per molecule])
A-2: Phthalic acid-based polyester polyol (manufactured by Kawasaki Kasei Kogyo Co., Ltd., product name: Maximol RDK-133, hydroxyl value: 315 mgKOH / g, number of functional groups: 2 [per molecule])

(B) Catalyst B-1: Potassium octylate (Momentive Performance Materials, product name: K-zero G)
B-2: Trimerization catalyst (product name: TOYOCAT-TR20, manufactured by Tosoh Corporation)
B-3: Pentamethyldiethylenetriamine (manufactured by Tosoh Corporation, product name: TOYOCAT-DT)

(C) Foam stabilizer Polyalkylene glycol foam stabilizer (manufactured by Dow Corning Toray, product name: SH-193, foam stabilizer of Table 1)

(D) Foaming agent D-1: Water D-2: HFC-365mfc (1,1,1,3,3-pentafluorobutane, manufactured by Nippon Solvay)
HFC-245fa (1,1,1,3,3-pentafluoropropane, manufactured by Central Glass Co., Ltd.)
Mixing ratio HFC-365mfc: HFC-245fa = 7: 3 (described as “HFC” in Table 1)

(E) Polyisocyanate compound MDI (manufactured by Tosoh Corporation, product name: Millionate MR-200, isocyanate content 30.5-32.0%)

(F) Flame retardant F-1: Red phosphorus (Rin Chemical Industry Co., Ltd., product name: Nova Excel 140)
F-2: Tris (β-chloropropyl) phosphate (manufactured by Daihachi Chemical Industry Co., Ltd., product name: TMCPP, hereinafter referred to as “TMCPP”)
F-3: Wollastonite (SiO2, CaO; acicular filler) (manufactured by Kinsei Matec, product name: SH-1250)

  The polyol compound, the catalyst, the foam stabilizer, the foaming agent, and the flame retardant shown in Table 1 were weighed so that the total amount became 10 kg, and stirred for 10 minutes to prepare a polyol premix. The polyol premix and polyisocyanate compound prepared above were put into separate tanks of a low pressure foaming machine (A310 type low pressure foaming machine manufactured by Toho Machine Industry Co., Ltd.).

A low pressure foaming machine containing the constituents of the flame retardant urethane resin composition was connected to a nozzle, and the flame retardant urethane resin composition was injected into the hollow steel pipe through the nozzle under the following conditions.
Polyol premix solution temperature: 25 ° C
Isocyanate temperature: 25 ° C
Mixing method: Using a low-pressure urethane foaming machine, the polyol premix and the isocyanate were mixed at a flow rate of 10 kg / min and a rotation speed of 3000 rpm / min by discharging a predetermined number of the amounts shown in Table 1 so as to achieve the target specific gravity. .

2. Evaluation of flame retardant polyurethane foam
[Measurement of flammability 1]
The flame retardant polyurethane compositions of Example 1 and Comparative Example 1 were poured into a steel pipe, and foamed and cured in a 70 ° C. oven.
The steel pipe after hardening of the foam was cut using a commercially available steel pipe cutting device (cutting temperature 1,300 ° C.), and the combustibility at that time was confirmed.
The case where the internal foam did not burn was marked with ◯, and the case where it burned was marked with x.

[Measurement of flammability 2]
The foams of the flame-retardant polyurethane foams of Example 1 and Comparative Example 1 molded into a sheet in an aluminum mold maintained at a mold temperature of 70 ° C. and cut to a thickness of 300 mm × 300 mm square and 50 mm A gas burner installed vertically and ignited on the surface was kept applied for 30 seconds.
After 30 seconds of flaming, the case where it did not burn was marked with ○, and the case where it burned was marked with ×.
As a result, in the foam of Example 1, both flammability 1 and 2 were good, but in the foam of Comparative Example 1, both flammability 1 and 2 were inferior.

  2 ... round steel pipe as steel pipe, 5 ... flame retardant polyurethane foam.

Claims (4)

A steel pipe filled with a flame retardant polyurethane foam containing a urethane resin and a flame retardant. The steel pipe according to claim 1, wherein the flame retardant polyurethane foam further includes a trimerization catalyst, and the flame retardant includes red phosphorus. The steel pipe according to claim 1 or 2, wherein the flame-retardant polyurethane foam is in direct contact with an inner peripheral surface of the steel pipe. The flame retardant comprises at least one flame retardant selected from the group consisting of phosphate-containing flame retardants, phosphate esters, bromine-containing flame retardants, metal hydroxides, needle fillers, and boron-containing flame retardants, The addition amount of the red phosphorus is in the range of 1 to 30 parts by mass with respect to 100 parts by mass of the urethane resin, and the addition amount of the at least one flame retardant is 1 to 70 with respect to 100 parts by mass of the urethane resin. The steel pipe according to claim 2 which is the range of a mass part.