JP2020128459A - Method for producing polyurethane foam - Google Patents

Abstract

The present invention provides a method for producing a polyurethane foam that can advantageously produce a polyurethane foam that is excellent in flame retardancy and has a uniform density distribution. SOLUTION: In producing a polyurethane foam according to a blow foaming method using a composition A containing a polyol as a main component and a powdery flame retardant and a composition B containing a polyisocyanate as a main component, Composition A prepared by using a powdery flame retardant having an average particle size of 50 μm or less and having a viscosity of 100 to 2000 mPa s at 20° C. is rotated at a rotation speed of 800 to 2000 rpm for 10 minutes. After stirring with a stirrer as described above, a polyurethane foam is produced by carrying out a blow foaming method. [Selection figure] None

Description

The present invention relates to a method for producing a polyurethane foam, and more particularly to a method capable of advantageously producing a polyurethane foam having excellent flame retardancy and a uniform density distribution.

BACKGROUND ART Conventionally, polyurethane foam has been mainly used as a heat insulating material by utilizing its excellent properties such as heat insulating property, adhesive property, and light weight property, as heat insulating material for interior and exterior wall materials for construction, panels, etc., metal siding, electric refrigerators, etc. It is used for heat insulation, heat insulation of building walls, ceilings, roofs, etc. of buildings, condominiums, frozen warehouses, etc., prevention of dew condensation, insulation of infusion pipes, etc., and backing material for filling voids generated in civil engineering work, civil engineering work It is also in practical use as a reinforcing material for such occasions. Further, such a polyurethane foam is generally a composition comprising a polyol compounding liquid (premix liquid) in which a foaming agent is further added to a polyol, and if necessary, various auxiliary agents such as a catalyst, a foam stabilizer and a flame retardant. A and a composition B containing polyisocyanate as a main component are continuously or intermittently mixed by a mixing device to obtain a foamable composition for polyurethane foam, which is slab foaming method, injection foaming method, It is manufactured by foaming and curing by a method such as a spray foaming method, a laminate continuous foaming method, a lightweight embankment construction method, and an injection backfill construction method.

By the way, since the polyurethane foam formed as described above is required to have flame retardancy in view of its application, a flame retardant is added as described in Patent Documents 1 to 3. It is known to impart flame retardancy to the resulting polyurethane foam by using a polyol component or the like.

However, when a polyurethane foam is produced according to a blowing foaming method using a polyol compounding liquid (composition A) containing a powdery flame retardant, the powdery flame retardant may hinder the progress of the urethane reaction. Further, since the specific gravity of the powdery flame retardant is generally higher than the specific gravity of the entire composition A, the powdery flame retardant contained in the composition A precipitates with the passage of time. When a polyurethane foam is produced by using the composition A in which such a powdery flame retardant is unevenly distributed, the obtained polyurethane foam has the flame retardant unevenly present, resulting in uneven flame retardance. May have.

JP-A-2002-47325 JP, 2005-193839, A JP, 2008-100405, A

Here, the present invention has been made in view of such circumstances, and the problem to be solved is that a polyurethane foam excellent in flame retardancy and having a uniform density distribution is formed by a blowing foaming method. According to the present invention, there is provided a method for producing a polyurethane foam which can be advantageously produced.

And in order to solve the above-mentioned subject, the present invention can be suitably carried out in various modes as enumerated below. It is understood that the aspects and technical features of the present invention are not limited to those described below and can be recognized based on the inventive idea that can be understood from the description of the specification. Should be.

(1) When a polyurethane foam is produced according to a blowing foaming method using a composition A containing a polyol as a main component and a powdery flame retardant and a composition B containing a polyisocyanate as a main component. ,
The average particle diameter of the powdery flame retardant is 50 μm or less,
The composition A having a viscosity of 100 to 2000 mPa·s at 20° C. is stirred with a stirrer at a rotation speed of 800 to 2000 rpm for 10 minutes or more, and then the blowing foaming method is performed.
A method for producing a polyurethane foam, comprising:
(2) The aspect (1) in which the powdery flame retardant is contained in the composition A at a ratio of 1 to 70 parts by mass with respect to 100 parts by mass of the polyol in the composition A. The method for producing a polyurethane foam according to 1.
(3) The method for producing a polyurethane foam according to aspect (1) or aspect (2), wherein the powdery flame retardant is surface-treated with an inorganic substance and/or an organic substance. (4) The aspect (1) to the aspect (wherein the powdery flame retardant has a specific gravity of 1.0 to 5.0).
The method for producing a polyurethane foam according to any one of 3).
(5) The polyurethane according to any one of the above aspects (1) to (4), wherein the powdery flame retardant has a specific gravity of 1 to 5 times the specific gravity of the composition A. Form manufacturing method.
(6) The method for producing a polyurethane foam according to any one of the aspects (1) to (5), wherein the blowing foaming method is performed while circulating the composition A in a storage tank. ..
(7) Production of the polyurethane foam according to any one of the aspects (1) to (6), wherein the pressure of the composition A supplied to the foaming machine in the blowing foaming method is 3 to 10 MPa. Method.
(8) In the aspect (1) to the aspect (7), the spray foaming method is carried out by mixing the composition A and the composition B with a foaming machine and spraying the mixture onto an object to be constructed. The method for producing a polyurethane foam according to any one of claims.
(9) The above aspect in which the blowing foaming method is performed by mixing a foaming agent that becomes a gas at room temperature with a foaming machine together with the composition A and the composition B, and spraying the mixture onto a construction object. (1) to the method for producing a polyurethane foam according to any one of the aspects (7).
(10) According to the blowing foaming method, 1) a lower blown layer made of polyurethane foam having a thickness of 2 to 10 mm is formed on a construction object, and 2) a thickness of 30 m is formed on the lower blown layer.
The method for producing a polyurethane foam according to any one of the above aspects (1) to (9), characterized in that one or more polyurethane foam layers of m or less are formed.

In the method for producing a polyurethane foam according to the present invention, the composition A containing a polyol as a main component contains a powdery flame retardant having an average particle diameter of not more than a predetermined size, and has a viscosity at 20° C. Is used within a predetermined range, and the composition A is subjected to a blowing foaming method after being stirred under predetermined stirring conditions. That is, in the present invention, the composition A in which the powdery flame retardant is not evenly distributed and is in a uniformly dispersed state is subjected to the blowing foaming method, and the finally obtained polyurethane foam is obtained. Since the flame retardant in a state of being uniformly dispersed is allowed to exist even inside, the polyurethane foam has excellent flame retardancy and has a uniform density distribution.

Further, in the production method of the present invention, the powdery flame retardant contained in the composition A has an average particle diameter of not more than a predetermined size, and such a powdery flame retardant is also used. The viscosity of the composition A containing A at 20° C. is adjusted within a predetermined range. Therefore, the powdery flame retardant is in a state where it is difficult to settle in the composition A, and in the composition A after being subjected to a predetermined stirring operation, the powdery flame retardant contained therein. A good dispersed state of is maintained for a long time, and even when it takes a long time from the stirring operation to the execution of the blowing foaming method, the obtained polyurethane foam has excellent flame retardancy and a density distribution. Will be uniform.

In the method for producing a polyurethane foam according to the present invention, the composition A containing a polyol as a main component and the composition B containing a polyisocyanate as a main component are mixed, foamed and cured to give a desired polyurethane foam. However, various known polyol compounds, which react with polyisocyanate to produce polyurethane, may be used alone or appropriately as the polyol, which is the main component constituting the composition A used therein. It is about to be used in combination with. And, there, polyether polyol, polyester polyol, etc. will be used suitably. Of course, in addition to these polyols, various known polyol compounds such as polyolefin-based polyols, acrylic-based polyols, polymer polyols, etc. can be used alone or in an appropriate combination, and needless to say. ..

Specifically, among such polyols, a polyether polyol is an alkylene oxide which is used as at least one initiator such as a polyhydric alcohol, a saccharide, an aliphatic amine, an aromatic amine, a phenol, and a Mannich condensation product. Is obtained by reacting with. Here, as the alkylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, ethylene oxide and the like can be mentioned. Further, the polyhydric alcohol as an initiator includes ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc., and the saccharides include sucrose, dextrose, sorbitol, etc. Further, the aliphatic amines include alkanolamines such as diethanolamine and triethanolamine, and polyamines such as ethylenediamine, and the aromatic amines include various methyl-substituted compounds of phenylenediamine generally called tolylenediamine. Other examples include derivatives in which a substituent such as methyl, ethyl, acetyl, benzoyl is introduced into the amino group, 4,4′-diaminodiphenylmethane, p-phenylenediamine, o-phenylenediamine, naphthalenediamine, and the like, Furthermore, examples of the phenols include bisphenol A and novolac type phenol resin. Examples of Mannich condensation products include Mannich condensation products obtained by subjecting phenols, aldehydes and alkanolamines to a Mannich condensation reaction.

Examples of polyester polyols include polyhydric alcohol-polyhydric carboxylic acid condensation type polyols and cyclic ester ring-opening polymerization type polyols. As the polyhydric alcohol, the above-mentioned ones can be used, and the dihydric alcohol is particularly preferably used. Examples of the polycarboxylic acid include succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, terephthalic acid, isophthalic acid, and their anhydrides. In addition, ε-caprolactone or the like is used as the cyclic ester.

Among them, as the polyester polyol, it is preferable to use an aromatic polyester polyol from the viewpoint of flame retardancy and compatibility, and specifically, it is preferable to use a phthalic acid polyester polyol, and further, such polyester It is also effective to combine two or more kinds of polyols. The phthalic acid-based polyester polyol is a polyol composed of a condensation product of phthalic acid, terephthalic acid, isophthalic acid and their anhydrides with a dihydric alcohol such as ethylene glycol, propylene glycol, diethylene glycol and dipropylene glycol. It is meant. When such a phthalic acid-based polyester polyol is used, even when performing on-site foaming at a low temperature (about -10°C to 5°C), peeling of the generated foam from the building frame or the like is unlikely to occur, and further on-site foaming occurs. There is an advantage that it is possible to obtain a rigid polyurethane foam having flexibility such that the treatment of the foam end portion after foaming is relatively easy. In particular, when a hydrofluoroolefin-based foaming agent or a hydrochlorofluoroolefin-based foaming agent is contained, the composition has a characteristic of giving excellent storage stability.

Further, in the present invention, among the above-mentioned polyols, a polyol having a specific gravity of preferably 1.0 to 1.5, more preferably a polyol having a specific gravity of 1.2 to 1.4, Used.

On the other hand, the polyisocyanate, which is the main component of the composition B, is added to the composition A and reacts with the polyol in the composition A to form a polyurethane (resin). An organic isocyanate compound having two or more isocyanate groups (NCO groups) in, for example, diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate, tolylene diisocyanate, polytolylene triisocyanate, xylylene diisocyanate, naphthalene diisocyanate, phenylene diisocyanate, Dimethyldiphenylmethane diisocyanate, aromatic polyisocyanates such as triphenylmethane triisocyanate, methylene diisocyanate, ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate and other aliphatic polyisocyanates, isophorone diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene In addition to alicyclic polyisocyanates such as diisocyanate, dicyclohexylmethane diisocyanate, and dimethyldicyclohexylmethane diisocyanate, urethane prepolymers having an isocyanate group at the molecular end, isocyanurate modified products of polyisocyanates, and carbodiimide modified products can be mentioned. These polyisocyanate compounds may be used alone or in combination of two or more kinds. Generally, polymethylene polyphenylene polyisocyanate (polymeric MDI) is preferably used from the viewpoints of reactivity, economy, handleability and the like.

The proportion of the polyisocyanate in the composition B and the polyol in the composition A described above is appropriately determined depending on the type of foam to be formed (for example, polyurethane or polyisocyanurate). However, generally, the NCO/OH index (equivalent ratio) showing the ratio of the isocyanate group (NCO) of the polyisocyanate to the hydroxyl group (OH) of the polyol is 0.9 to 4.5, preferably 1.5 to 4.0. It will be appropriately determined to be within the range of the degree.

In the present invention, the composition A containing a polyol as a main component as described above and the composition B containing a polyisocyanate as a main component are mixed and reacted, and at the same time, foamed by a foaming agent and cured. As a result, a polyurethane foam is formed. In the reaction between the composition A and the composition B, a catalyst is generally used. In the present invention, preferably a trimerization catalyst, in other words, a catalyst (isocyanurate-forming catalyst) that reacts with an isocyanate group of a polyisocyanate to trimerize and promote the formation of an isocyanurate ring is added to the composition A. It will be included. As the trimerization catalyst, it is possible to appropriately select and use various known ones, but it is preferable to use a quaternary ammonium salt, potassium octylate, potassium 2-ethylhexanoate, sodium acetate. Alkali metal salts of carboxylic acids such as; Tris(dimethylaminomethyl)phenol, 2,4-bis(dimethylaminomethyl)phenol, tris(dimethylaminopropyl)hexahydrotriazine and other nitrogen-containing aromatic compounds; Trimethylammonium salt, triethyl Examples thereof include tertiary ammonium salts such as ammonium salts and triphenylammonium salts. Among these, it is preferable to use a quaternary ammonium salt from the viewpoint of improving flame retardancy, and in particular, it is preferable to use a quaternary ammonium salt in combination with an alkali metal carboxylic acid salt to further improve flame retardancy. From the viewpoint of improvement, it is particularly preferable.

As the quaternary ammonium salt advantageously used here, tetramethylammonium, methyltriethylammonium, ethyltrimethylammonium, propyltrimethylammonium, butyltrimethylammonium, pentyltrimethylammonium, hexyltrimethylammonium, heptyltrimethylammonium, octyltrimethylammonium, Aliphatic ammonium such as nonyl trimethyl ammonium, decyl trimethyl ammonium, undecyl trimethyl ammonium, dodecyl trimethyl ammonium, tridecyl trimethyl ammonium, tetradecyl trimethyl ammonium, heptadecyl trimethyl ammonium, hexadecyl trimethyl ammonium, heptadecyl trimethyl ammonium, octadecyl trimethyl ammonium Compounds, hydroxyammonium compounds such as (2-hydroxypropyl)trimethylammonium, hydroxyethyltrimethylammonium, trimethylaminoethoxyethanol, hydroxyethyl-2-hydroxypropyldimethylammonium, 1-methyl-1-azania-4-azabicyclo[2,2] Examples of the alicyclic ammonium compound such as 2,2]octanium, 1,1-dimethyl-4-methylpiperidinium, 1-methylmorpholinium, and 1-methylpiperidinium. Among these, excellent catalytic activity, from industrially available, tetramethylammonium, methyltriethylammonium, ethyltrimethylammonium, butyltrimethylammonium, hexyltrimethylammonium, octyltrimethylammonium, decyltrimethylammonium, dodecyltrimethylammonium, Tetradecyltrimethylammonium, hexadecyltrimethylammonium, octadecyltrimethylammonium, (2-hydroxypropyl)trimethylammonium, hydroxyethyltrimethylammonium, hydroxyethyl-2-hydroxypropyldimethylammonium, 1-methyl-1-azania-4-azabicyclo[ 2,2,2]octanium and 1,1-dimethyl-4-methylpiperidinium will be preferably used.

Examples of the organic acid group or the inorganic acid group constituting the quaternary ammonium salt as described above include, for example, formic acid group, acetic acid group, octyl acid group, oxalic acid group, malonic acid group, succinic acid group, glutaric acid group, Organic acid groups such as adipic acid group, benzoic acid group, toluic acid group, ethyl benzoic acid group, methyl carbonate group, phenol group, alkylbenzene sulfonic acid group, toluene sulfonic acid group, benzene sulfonic acid group, and phosphoric acid ester group, Inorganic acid groups such as a halogen group, a hydroxyl group, a hydrogen carbonate group and a carbonic acid group can be used. Among these, formic acid groups, acetic acid groups, octylic acid groups, methyl carbonate groups, halogen groups, hydroxyl groups, hydrogen carbonate groups, and carbonate groups are preferable because they have excellent catalytic activity and are industrially available.

Further, various catalysts made of such a quaternary ammonium salt are commercially available, and examples thereof include U-CAT 18X, U-CAT 2313 (manufactured by San-Apro Co., Ltd.), Kaorizer No. 410, Kaurizer No. 420 (manufactured by Kao Corporation) and the like can be mentioned.

In addition, as described above, the amount of the trimerization catalyst used as one of the catalysts is 0 with respect to 100 parts by mass of the entire polyol in the composition A in order to effectively exhibit the function as the catalyst. 1-10 parts by mass, preferably 0.5-8 parts by mass, more preferably 1-6 parts by mass. When the amount of the trimerization catalyst used is less than 0.1 part by mass, the trimerization of polyisocyanate cannot be sufficiently realized, and thus it becomes difficult to sufficiently achieve the flame retardancy improving effect. On the other hand, when the amount is more than 10 parts by mass, the reaction proceeds too much and the solidification is accelerated, which makes spraying difficult.

In the present invention, it is also possible to use a urethanization catalyst which is a resinization catalyst together with such a trimerization catalyst. Examples of the urethanization catalyst include fatty acid bismuth salts such as dibutyltin dilaurate, bismuth octylate (bismuth 2-ethylhexylate), bismuth neodecanoate, bismuth neododecanoate, bismuth naphthenate, and lead naphthenate. I can.

Further, the amount of the resinification catalyst used is 0.1 to 10 parts by mass, preferably 0 to 100 parts by mass of the entire polyol in the composition A, so that the function as the catalyst can be effectively exhibited. It will be selected in the range of 0.5 to 8 parts by mass, more preferably 1 to 6 parts by mass. If the amount of the resinification catalyst used is less than 0.1 parts by mass, the resulting foam may be sticky, dust, etc. may adhere to the foam, resulting in poor appearance. There is a problem such as poor workability because the droplets that adhere to the product become sticky. On the other hand, if it exceeds 10 parts by mass, the heat generated during the resinification reaction will increase and the appearance of the foam, such as yellowing, will be abnormal. However, the catalyst containing the quaternary ammonium salt contained in the droplets generated during foaming may deteriorate the work environment at the work site where the spraying work is performed.

On the other hand, in the present invention, a powdery flame retardant is added to the composition containing the above-mentioned polyol as a main component. In the present invention, the amount of the powdery flame retardant used is 1 to 70 parts by mass, preferably 10 to 60 parts by mass, and more preferably 20 to 55 parts by mass, relative to 100 parts by mass of the polyol in the composition A. Determined within the scope of the section. If the amount of powdery flame retardant added is too small, the resulting polyurethane foam may not be able to exhibit sufficient flame retardancy, and if the amount added is too large, the viscosity of composition A will increase. In addition to increasing the temperature and causing problems such as poor stirring, there is a risk of causing problems such as a decrease in workability and a problem that the polyurethane foam becomes rather easy to burn.

Here, in the production method according to the present invention, the average particle diameter of the powdery flame retardant used is 50 μm or less, preferably 0.1 to 50 μm, more preferably 0.5 to 40 μm, and further preferably 1 to It is 35 μm. As the composition A containing a polyol as a main component, a composition containing a powdery flame retardant having an average particle size of 50 μm or less and prepared to have a viscosity within a predetermined range is used. Since the sedimentation rate of the powdery flame retardant therein is effectively slowed down and the good dispersion state of the powdery flame retardant can be maintained for a long time, the effect of the present invention can be enjoyed.

Further, in the finally obtained polyurethane foam, the specific gravity of the powdery flame retardant is preferably 1.0 to 5.0 in order to make the dispersed state of the powdery flame retardant better. It is preferably 1.2 to 4.5, and more preferably 1.6 to 4.0.

Furthermore, the specific gravity of the powdery flame retardant is preferably 1 time or more and 5 times or less, more preferably 1 time or more and 4.5 times or less, and further preferably 1. It is 2 times or more and 4 times or less. In the composition A, the specific gravity of the powdery flame retardant is preferably 1 time or more of the specific gravity of the composition A so that the powdery flame retardant does not float up. On the other hand, by reducing the difference in the specific gravity between the powdery flame retardant and the composition A, the sedimentation speed of the powdery flame retardant in the composition A becomes slower. It is preferable that the specific gravity is 5 times or less.

In the method for producing a polyurethane foam according to the present invention, any conventionally known flame retardant can be used as long as it is in powder form, and it is usually used by appropriately selecting from commercial products. It will be. Examples of the powdery flame retardant usable in the present invention include red phosphorus, phosphate-containing flame retardants, stannate-containing flame retardants, boron-containing flame retardants, metal hydroxides and metal oxides. Yes, one or more of them are selected and added to the composition A and/or the composition B.

-Red phosphorus-
Any conventionally known red phosphorus can be used.

-Phosphate-containing flame retardant-
The phosphate-containing flame retardant is one that contains a phosphate and has flame retardancy. The phosphoric acid used in the phosphate-containing flame retardant is not particularly limited, and various phosphoric acids such as monophosphoric acid, pyrophosphoric acid and polyphosphoric acid can be exemplified.

Further, as the phosphate-containing flame retardant, for example, the above-mentioned various phosphoric acids, and at least one metal selected from the metals of group IA to IVB of the periodic table, ammonia, aliphatic amines, aromatic amines or compounds thereof. The phosphate consisting of the salt of and can be mentioned. Examples of metals of Group IA to IVB of the Periodic Table include lithium, sodium, calcium, barium, iron (II), iron (III), aluminum and the like. Examples of the aliphatic amine include methylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, piperazine and the like, and examples of the aromatic amine include pyridine, triazine, melamine, ammonium and the like. The phosphate-containing flame retardant used in the present invention may be one to which a known water resistance improving treatment such as silane coupling agent treatment and coating with a melamine resin has been added, and melamine, pentaerythritol, etc. A known foaming auxiliary agent may be added.

Specific examples of the phosphate constituting the phosphate-containing flame retardant used in the present invention include monophosphate, pyrophosphate and polyphosphate.

The monophosphate is not particularly limited, and examples thereof include ammonium phosphate, ammonium dihydrogen phosphate, ammonium salts such as diammonium hydrogen phosphate, monosodium phosphate, disodium phosphate, and trisodium phosphate. , Monosodium phosphite, disodium phosphite, sodium salts such as sodium hypophosphite, monopotassium phosphate, dipotassium phosphate, tripotassium phosphate, monopotassium phosphite, dipotassium phosphite, Potassium salts such as potassium hypophosphite, lithium lithium phosphate, dilithium phosphate, trilithium phosphate, lithium lithium phosphite, dilithium phosphite, lithium salts such as lithium hypophosphite, diphosphate Barium hydrogen, barium hydrogen phosphate, tribarium phosphate, barium hypophosphite and other barium salts, magnesium monohydrogen phosphate, magnesium hydrogen phosphate, trimagnesium phosphate, magnesium hypophosphite and other magnesium salts, phosphorus Examples thereof include calcium dihydrogen acid, calcium hydrogen phosphate, tricalcium phosphate, calcium hypophosphite, and other calcium salts; zinc phosphate, zinc phosphite, zinc hypophosphite, and other zinc salts.

The polyphosphate is not particularly limited, and examples thereof include ammonium polyphosphate, piperazine polyphosphate, melamine polyphosphate, ammonium polyphosphate amide, and aluminum polyphosphate.

In the present invention, it is possible to appropriately select and use one kind or two or more kinds from the conventionally known phosphate-containing flame retardants including those mentioned above. Among the above-mentioned phosphates, monophosphates are advantageously used, and ammonium dihydrogenphosphate is more advantageously used, in terms of excellent self-extinguishing property.

-Stannate-containing flame retardant-
The stannate-containing flame retardant is a flame retardant containing a metal stannate salt. Here, examples of the stannic acid metal salt contained in the stannate-containing flame retardant include zinc stannate, barium stannate, sodium stannate, potassium stannate, cobalt stannate, and magnesium stannate. Of these, zinc stannate is preferably used.

-Boron-containing flame retardant-
Examples of the boron-containing flame retardant used in the present invention include borax, boron oxide, boric acid, borate and the like. Specific examples of the boron oxide include diboron trioxide, boron trioxide, diboron dioxide, tetraboron trioxide, tetraboron pentaoxide and the like. In addition, examples of the borate include alkali metal, alkaline earth metal, elements of Group 4, Group 12, and Group 13 of the periodic table, ammonium borate, and the like. More specifically, lithium borate, sodium borate, potassium borate, cesium borate, and other alkali metal borate salts; magnesium borate, calcium borate, barium borate, and other alkaline earth metal borate salts; Examples thereof include zirconium borate, zinc borate, aluminum borate, ammonium borate and the like.

In the present invention, it is possible to appropriately select and use one kind or two or more kinds from the conventionally known boron-containing flame retardants including those mentioned above. Among the above-mentioned boron-containing flame retardants, borate is preferably used, and zinc borate is more preferably used.

-Metal hydroxide-
In the present invention, examples of the metal hydroxide used as the flame retardant include magnesium hydroxide, calcium hydroxide, aluminum hydroxide, iron hydroxide, nickel hydroxide, zirconium hydroxide, titanium hydroxide, zinc hydroxide. , Copper hydroxide, vanadium hydroxide, tin hydroxide and the like. One or two or more of these known materials are appropriately selected and used.

-Metal oxide-
In the present invention, examples of the metal oxide used as the flame retardant include zinc oxide, aluminum oxide, titanium oxide and the like. One or two or more of these known materials are appropriately selected and used.

Among the above-mentioned powdery flame retardants, in the present invention, those surface-treated with an inorganic substance and/or an organic substance are advantageously used from the viewpoint of safety and ease of handling. In particular, coated red phosphorus is advantageously used. The coated red phosphorus is red phosphorus that is surface-treated with an inorganic substance and/or an organic substance, and commercially available coated red phosphorus includes Novarred (trade name, manufactured by Rin Kagaku Kogyo Co., Ltd.) Excel (trade name, manufactured by Rin Kagaku Kogyo Co., Ltd.), Hishiguard (trade name, manufactured by Nippon Kagaku Kogyo Co., Ltd.) and the like can be exemplified. As the coated red phosphorus, the one having a high content ratio of red phosphorus contributes more effectively to the improvement of the flame retardancy of the polyurethane foam, and therefore the red phosphorus component is 80% or more, preferably 80 to 99%, Coated red phosphorus, preferably 90-98%, is advantageously used.

On the other hand, in the production method of the present invention, a liquid flame retardant can be used together with the powdery flame retardant described above. By using a powdery flame retardant and a liquid flame retardant in combination, it is possible to further improve the flame retardancy of the finally obtained polyurethane foam, and to improve the viscosity of the composition A and the composition B. It is also possible to reduce. In the present invention, a phosphoric acid ester, a bromine-containing flame retardant or the like can be used as the liquid flame retardant.

-Phosphate ester-
Examples of the phosphoric acid ester include monophosphoric acid ester and condensed phosphoric acid ester.

The monophosphate is not particularly limited, and examples thereof include trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri(2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl. Phosphate, tris(isopropylphenyl)phosphate, tris(phenylphenyl)phosphate, trinaphthylphosphate, cresyldiphenylphosphate, xylenyldiphenylphosphate, diphenyl(2-ethylhexyl)phosphate, di(isopropylphenyl)phenylphosphate, monoisodecyl Phosphate, 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, melamine phosphate, dimelamine phosphate, melamine pyrophosphate, triphenylphosphine Oxide, tricresylphosphine oxide, diphenyl methanephosphonate, diethyl phenylphosphonate, resilcinol bis (diphenyl phosphate), bisphenol A bis (diphenyl phosphate), phosphaphenanthrene, tris (β-chloropropyl) phosphate, etc. , Can be listed.

Also, the condensed phosphoric acid ester is not particularly limited, and examples thereof include trialkyl polyphosphate, resorcinol polyphenyl phosphate, resorcinol poly(di-2,6-xylyl) phosphate (trade name, manufactured by Daihachi Chemical Industry Co., Ltd.). : PX-200), hydroquinone poly(2,6-xylyl) phosphate, condensates of these, and the like. Examples of commercially available condensed phosphates other than those mentioned above include resorcinol polyphenyl phosphate (trade name: CR-733S), bisphenol A polycresyl phosphate (trade name: CR-741), aromatic condensed phosphate ester. (Trade name: CR747), resorcinol polyphenyl phosphate (made by ADEKA, trade name: ADEKA STAB PFR), bisphenol A polycresyl phosphate (trade names: FP-600, FP-700) and the like can be mentioned.

In the present invention, one or two or more kinds can be appropriately selected from among the conventionally known phosphoric acid esters including the monophosphoric acid ester and the condensed phosphoric acid ester, and can be used. is there. Further, among the monophosphates and condensed phosphates described above, it is possible to use a monophosphate in that the effect of lowering the viscosity of the composition before curing and the effect of reducing the initial calorific value are high. It is more preferable to use tris(β-chloropropyl)phosphate.

-Bromine-containing flame retardant-
The bromine-containing flame retardant used in the present invention is not particularly limited as long as it is a compound containing bromine in its molecular structure, and examples thereof include various aromatic brominated compounds. Specifically, hexabromobenzene, pentabromotoluene, hexabromobiphenyl, decabromobiphenyl, hexabromocyclodecane, decabromodiphenyl ether, octabromodiphenyl ether, hexabromodiphenyl ether, bis(pentabromophenoxy)ethane, ethylene-bis( Monobromoorganic compounds such as tetrabromophthalimide) and tetrabromobisphenol A; brominated polycarbonates such as polycarbonate oligomers produced from brominated bisphenol A as a raw material, copolymers of the above-mentioned polycarbonate oligomer and bisphenol A; brominated bisphenols Brominated epoxy compounds such as diepoxy compounds produced by the reaction of A with epichlorohydrin and monoepoxy compounds obtained by the reaction of brominated phenols with epichlorohydrin; poly(brominated benzyl acrylate); brominated polyphenylene ether; brominated Condensate of bisphenol A, cyanuric chloride and brominated phenol; brominated polystyrene such as brominated (polystyrene), poly(brominated styrene), crosslinked brominated polystyrene; crosslinked or non-crosslinked brominated poly(-methylstyrene) Mention may be made of halogenated bromine compound polymers and the like.

In the present invention, it is possible to appropriately select and use one kind or two or more kinds from the conventionally known bromine-containing flame retardants including those mentioned above. Among the above-mentioned bromine-containing flame retardants, brominated polystyrene, hexabromobenzene, etc. are advantageously used, and hexabromobenzene is more advantageously used, from the viewpoint of controlling the calorific value in the early stage of combustion.

As described above, the powdery flame retardant and the liquid flame retardant that can be used in the present invention have been illustrated and described, but in the present invention, other powdery flame retardants are included together with the powdery flame retardant red phosphorus. It is possible to further improve the flame retardancy of the polyurethane foam finally obtained by using together and/or a liquid flame retardant.

By the way, in the method for producing a polyurethane foam according to the present invention, a foaming agent is used as in the conventional method for producing a polyurethane foam. Examples of the foaming agent used in the present invention include water, hydrocarbons, hydrofluorocarbons, halogenated olefins, liquefied CO ₂ (critical, subcritical or liquid carbon dioxide), and the like.

Water produces carbon dioxide by reacting with polyisocyanate, and the carbon dioxide functions as a foaming agent. In addition, heat of reaction is generated during the reaction of water and polyisocyanate, and by the heat, urethanization reaction and isocyanurate reaction can be effectively progressed, and the compression strength of the obtained polyurethane foam is increased. There is also an advantage that it can be further enhanced. However, when the amount of such water used is too large, the strength is rather lowered. This is because the urea bond generated by the reaction between water and polyisocyanate increases in the resin, and the polyisocyanate used for the isocyanurate-forming reaction is consumed by the reaction with water, and the polyisocyanate in the reaction system decreases. This is because. As described above, in the present invention, it is preferable that water as a foaming agent is contained in the composition A containing a polyol as a main component, and the content (usage) is 100 parts by mass of the polyol in the composition A. On the other hand, the amount is preferably 5 parts by mass or less, preferably 4 parts by mass or less, more preferably 3 parts by mass or less, and in order to sufficiently exert the effect of the presence of water, 0.1 parts by mass or more, preferably It is desirable that the amount is 0.5 parts by mass or more, and more preferably 1 part by mass or more. In addition, such water is added and blended separately as a blending component for forming the composition A, and is also added and blended as water contained in other blending components such as polyol, and The water contained by moisture absorption during the storage of the composition A is also taken into consideration, and the total amount thereof is adjusted to be a ratio within the above-specified range.

Then, due to the presence of water in the composition A as described above, the composition A containing a polyol as a main component and the composition B containing a polyisocyanate as a main component are mixed and reacted with each other. Carbon dioxide is generated by the reaction with polyisocyanate, and this carbon dioxide also contributes to the foaming of polyurethane. In the present invention, when an organic foaming agent or liquefied CO ₂ described below is used, carbon dioxide generated by a reaction between water in the composition A and polyisocyanate and carbon dioxide used as liquefied CO ₂ described below. The organic foaming agent described below is present in the mixture of the composition A and the composition B such that the content of the organic foaming agent described below is more than 1 mol and not more than 20 mol per 1 mol of the total amount of It is confused.

In the present invention, as a foaming agent, instead of or together with the above-mentioned water, an organic foaming agent such as hydrocarbon (HC), hydrofluorocarbon (HFC), hydrofluoroolefin (HFO) or hydrochlorofluoroolefin (HCFO). It is possible to use halogenated olefins (halogenated alkenes) referred to as ). HFC is classified as a chlorofluorocarbon foaming agent, and HC, HFO, and HCFO are classified as a non-fluorocarbon foaming agent.

Examples of the hydrocarbon (HC) that can be used in the present invention include propane, normal pentane, isopentane, cyclopentane, butane, isobutane, hexane, isohexane, neohexane, heptane, isoheptane, and the like. Examples of the fluorocarbon (HFC) include difluoromethane (HFC32), 1,1,1,2,2-pentafluoroethane (HFC125), 1,1,1-trifluoroethane (HFC143a), 1,1,2. ,2-tetrafluoroethane (HFC134), 1,1,1,2-tetrafluoroethane (HFC134a), 1,1-difluoroethane (HFC152a), 1,1,1,2,3,3,3-heptafluoro Propane (HFC227ea), 1,1,1,3,3-pentafluoropropane (HFC245fa), 1,1,1,3,3-pentafluorobutane (HFC365mfc), and 1,1,1,2,2,2. Examples include 3,4,5,5,5-decafluoropentane (HFC4310mee), dichloroethane, propyl chloride, isopropyl chloride, butyl chloride, isobutyl chloride, pentyl chloride, isopentyl chloride.

The halogenated olefins (halogenated alkenes) that can be used in the present invention include those called hydrofluoroolefins (HFO) and hydrochlorofluoroolefins (HCFO), and generally, chlorine and fluorine are used as halogens. Is an unsaturated hydrocarbon derivative having about 2 to 6 carbon atoms, which is bonded and contained. For example, tetrafluoropropene, pentafluoropropene, hexafluorobutene and other propenes having 3 to 6 fluorine substituents, butene, pentene and hexene, and fluorochloropropene, trifluoromonochloropropene, fluorochlorobutene. And the like, and unsaturated hydrocarbons having a fluorine substituent and a chlorine substituent, and mixtures of two or more thereof. Examples of the hydrofluoroolefin (HFO) include pentafluoropropene such as 1,2,3,3,3-pentafluoropropene (HFO1225ye), 1,3,3,3-tetrafluoropropene (HFO1234ze), 2, Tetrafluoropropenes such as 3,3,3-tetrafluoropropene (HFO1234yf) and 1,2,3,3-tetrafluoropropene (HFO1234ye), trifluoropropenes such as 3,3,3-trifluoropropene (HFO1243zf) , Tetrafluorobutene isomers (HFO1354), pentafluorobutene isomers (HFO1345), 1,1,1,4,4,4-hexafluoro-2-butene (HFO1336mzz) and other hexafluorobutene isomers ( HFO1336), heptafluorobutene isomer (HFO1327), heptafluoropentene isomer (HFO1447), octafluoropentene isomer (HFO1438), nonafluoropentene isomer (HFO1429), and the like. In addition, as hydrochlorofluoroolefin (HCFO), 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), Dichlorotrifluoropropene (HCFO1223), 1-chloro-2,3,3-trifluoropropene (HCFO-1233yd), 1-chloro-1,3,3-trifluoropropene (HCFO-1233zb), 2-chloro- 1,3,3-Trifluoropropene (HCFO-1233xe), 2-chloro-2,2,3-trifluoropropene (HCFO-1233xc), 3-chloro-1,2,3-trifluoropropene (HCFO-) 1233ye), 3-chloro-1,1,2-trifluoropropene (HCFO-1233yc) and the like.

In particular, the above-mentioned hydrofluoroolefin (HFO) and hydrochlorofluoroolefin (HCFO) have a low global warming potential and are attracting attention as an environmentally friendly foaming agent, and thus are advantageously used in the present invention.

The amount of the organic blowing agent (hydrocarbon, hydrofluorocarbon, halogenated olefin) used is preferably 5 to 50 parts by mass, more preferably 10 to 40 parts by mass, relative to 100 parts by mass of the polyol in the composition A. It is preferably part. When the amount of the organic foaming agent used exceeds 50 parts by mass, the core density of the finally obtained polyurethane foam becomes low, which may lead to a decrease in the strength of the foam and a deterioration in dimensional stability. There is. There is also a problem in terms of cost. On the other hand, when the amount of the organic foaming agent used is less than 5 parts by mass, the function as the foaming agent cannot be sufficiently exhibited, and the density of the obtained foam may increase, and the composition When it is used by adding it to A, if the addition amount is too small, the viscosity of the composition A as a whole becomes high and the mixing property with the composition B deteriorates. For example, in a blowing foaming method using a spray gun. However, it causes a problem that a good spray pattern cannot be obtained.

Further, in the present invention, an organic foaming agent (hydrocarbon, hydrofluorocarbon, halogenated olefin) is used by adding it to either or both of the compositions A and B when preparing them. However, when liquefied CO ₂ (critical, subcritical or liquid carbon dioxide) described later is also used as the foaming agent together with the organic foaming agent, the organic foaming agent is added to the liquefied CO ₂ before use. It is possible. With the addition of the organic foaming agent in a liquefied CO ₂ include, for boiling point of the mixture of liquefied CO ₂ compound and an organic blowing agent is higher than the boiling point of the liquefied CO ₂ such (-78.5 ° C.), liquefied CO ₂ There is an advantage that a device or equipment for cooling the type becomes unnecessary. As the organic blowing agent used is added to the liquefied CO ₂ include, preferably halogenated olefin in terms of impact on the environment, also, the mixing ratio (weight ratio) relative to the liquefied CO ₂ class is liquefied CO ₂ Class: organic foaming agent=1:9 to 9:1, preferably liquefied CO ₂ class: organic foaming agent=2:8 to 8:2.

Further, in the present invention, when an organic foaming agent (hydrocarbon, hydrofluorocarbon, halogenated olefin) and water are used together as a foaming agent, the mass ratio of the organic foaming agent and water is 60:40 to 99.9: It is desirable to use it in a ratio of 0.1, preferably 70:30 to 99:1, more preferably 80:20 to 98:2. If the water content is out of this range and exceeds 40, brittleness develops as the reaction progresses, the adhesiveness to the body surface decreases, and problems such as peeling may occur. Further, carbon dioxide generated by the reaction with isocyanate lowers the thermal conductivity, and there is a possibility that a foamed layer having insufficient thermal conductivity is formed. When water is used as the foaming agent, water is preferably added to the composition A.

Further, in the present invention, liquefied CO ₂ that can be used as a foaming agent is critical, subcritical or liquid carbon dioxide, and as is well known, carbon dioxide gas is pressurized under a predetermined temperature. As a result, it is in a supercritical state, a subcritical state, or a liquid state, and changes from liquid to gas (phase transition) at room temperature. Specifically, liquid carbon dioxide is liquefied under conditions of temperature and pressure above the triple point, and carbon dioxide in a subcritical state has a pressure above the critical pressure and a temperature below the critical temperature. Liquid state carbon dioxide, pressure less than the critical pressure and temperature above the critical temperature liquid state carbon dioxide, or temperature and pressure below the critical point, but in a state close to this Further, the carbon dioxide in the supercritical state is a carbon dioxide in a fluid state in which both the pressure and the temperature exceed the critical point of the critical pressure or the critical temperature or higher.

Since the liquefied CO ₂ described above exerts an effective foaming action immediately after addition to the composition A or the like, the composition A and the composition A are treated from the start to the end of the reaction between the polyol and the polyisocyanate. It improves the dispersibility of the powdery flame retardant in the mixture with B, contributes to the thinning of the skin layer in the resulting polyurethane foam, and advantageously realizes its low density. .. Further, by using the liquefied CO ₂ , the sprayability of the mixture comprising the composition A and the composition B is improved in the spray foaming method described later, and in addition, the spray resulting from the powdery flame retardant is used. The occurrence of clogging in the gun is advantageously suppressed. In the present invention, when the amount of liquefied CO ₂ used is too small, the effect of addition cannot be sufficiently exhibited, and foaming immediately after spraying by the spray foaming method becomes insufficient, resulting in a core layer and a skin layer. Since the difference in density between the two becomes large, problems such as a decrease in compressive strength and an increase in the dimensional change rate are caused. On the other hand, if the amount of the liquefied CO ₂ used is too large, the gas (carbon dioxide) generated in the initial stage of the reaction becomes excessive, which adversely affects the foaming characteristics, and the foaming is excellent in the spraying in the spray foaming method. Problems such as difficulty in obtaining the body are caused. Therefore, in the present invention, the amount of the liquefied CO ₂ used is preferably in the range of 0.1 to 4 parts by mass, more preferably 0, based on 100 parts by mass of the polyol in the composition A. .2 to 3 parts by mass.

Such liquefied CO ₂ is produced in the composition A containing a polyol as a main component by a carbon dioxide supply device as disclosed in, for example, JP 2011-247323 A at the production site of polyurethane foam. It is supplied to the flow channel or the flow channel of the composition B having polyisocyanate as a main component and mixed, and contributes to the foaming of the polyurethane generated by the reaction between the polyol and the polyisocyanate. Of course, such supply of liquefied CO ₂ is carried out directly to the position where the composition A and the composition B are brought into contact with each other and mixed, and the liquefied CO ₂ is supplied to both of them. It is also possible to do so.

As described above, the composition used for producing the polyurethane foam according to the production method of the present invention has been described in detail for each of the components. Any additives can be used as long as they do not impair the object of the present invention. A foam stabilizer can be illustrated as such an additive. The foam stabilizer is used for uniformly adjusting the cell structure of the polyurethane foam, and in the present invention, a silicone type or a nonionic surfactant is preferably adopted. Specific examples include polyoxyalkylene-modified dimethylpolysiloxane, polysiloxaneoxyalkylene copolymer, polyoxyethylene sorbitan fatty acid ester, castor oil ethylene oxide adduct, lauryl fatty acid ethylene oxide adduct, and the like. One type may be used alone, or two or more types may be used in combination. The blending amount of the foam stabilizer is appropriately determined according to the desired foam characteristics, the type of the foam stabilizer used, etc., but is 100 parts by mass of the total polyol in the composition A. On the other hand, it is selected in the range of 0.1 to 10 parts by mass, preferably 1 to 8 parts by mass.

Then, a composition A containing a polyol as a main component and a composition B containing a polyisocyanate as a main component will be prepared by using each of the above-mentioned components. The composition A is prepared so that the viscosity of the composition A falls within a predetermined range.

Specifically, the composition A is prepared so that the viscosity at 20° C. is 50 to 2000 mPa·s, preferably 100 to 1800 mPa·s, and more preferably 120 to 1500 mPa·s. When the viscosity of the composition A at 20° C. is less than 50 mPa·s, the powdery flame retardant may not exhibit a good dispersed state in the composition, and from the viewpoint of satisfactorily performing the blowing and foaming method, The viscosity of the composition A at 20° C. is 2000 mPa·s or less. The viscosity of the composition A means the viscosity of the entire composition formed by adding a powdery flame retardant, a catalyst and the like to the polyol. Moreover, when adjusting the viscosity of the composition A (and the composition B), various organic solvents and the like can be used as long as they do not impair the object of the present invention.

The viscosity of the composition B used in the present invention is not particularly limited, but the viscosity at 20° C. is preferably 50 to 1500 mPa·s, more preferably 80 to 1000 mPa·s. The composition B is prepared so as to be s, more preferably 100 to 800 mPa·s. If the viscosity of the composition B at 20° C. is less than 50 mPa·s, the powdery flame retardant may not be in a good dispersed state in the finally obtained polyurethane foam, and the blowing foaming method may be well performed. From this viewpoint, the viscosity of the composition B at 20° C. is preferably 1500 mPa·s or less.

In the method for producing a polyurethane foam according to the present invention, the composition A and the composition B described above are used to produce a polyurethane foam according to the blowing and foaming method. The composition A containing the flame retardant at a rotation speed of 800 to 2000 rpm, preferably at a rotation speed of 900 to 1800 rpm, is 10 minutes or longer, preferably 15 minutes or longer, more preferably 30 minutes or longer, with a stirrer. After being agitated, they are subjected to a blowing foaming method. By carrying out the blowing and foaming method using the composition A subjected to such a stirring operation, the obtained polyurethane foam has excellent flame retardancy and a uniform density distribution. Further, in the present invention, the powdery flame retardant contained in the composition A has an average particle diameter of not more than a predetermined size, and the viscosity of the composition A at 20° C. is within a predetermined range. As it is prepared, such a composition A has a dispersion of the powdery flame retardant in the composition A even after a long time (for example, 5 to 10 hours) has passed from the stirring operation described above. The condition will be maintained in good condition. Therefore, even when using the composition A after a long time has passed from such a stirring operation, according to the present invention, a polyurethane foam having excellent flame retardancy and a uniform density distribution can be produced. It is possible.

Further, in the present invention, it is advantageous that the blowing foaming method is carried out while circulating the composition A in the storage tank. As a result, the composition A in which the powdery flame retardant is in a better dispersed state is subjected to the blowing and foaming method, and the effects of the present invention can be more advantageously enjoyed. As a method of circulating the composition A in the storage tank, 1) a part of the composition A supplied from the storage tank is returned to the storage tank to circulate the composition A in the storage tank. The method and 2) a method of installing a stirring blade in the storage tank, stirring the inside of the tank with the stirring blade, and circulating the stirring blade can be exemplified.

Here, the blowing foaming method used in the present invention is not particularly limited as long as it is conventionally known. As such a foaming method, 1) a method in which the composition A and the composition B are mixed in a foaming machine and the mixture is sprayed on a construction object (referred to as the first method in this paragraph), or 2) the composition A method of mixing a foaming agent that becomes a gas at room temperature with A and the composition B in a foaming machine and spraying the mixture onto a construction object (referred to as a second method in this paragraph) and the like can be exemplified. The first method is advantageously adopted in that the foaming machine is simplified and the blowing foaming method can be carried out at low cost, while the dispersibility of the powdery flame retardant in the mixture is improved. The second method is advantageously adopted in that it can be further improved and the occurrence of clogging in the spray gun can be reduced. When the composition A and the composition B are mixed, the reaction between the polyol and the polyisocyanate starts immediately after the mixing. Therefore, the above-mentioned mixture also contains a reaction product between the polyol and the polyisocyanate. But should be understood. Further, as the foaming agent which becomes a gas at room temperature, the above-mentioned liquefied CO ₂ species (critical, subcritical or liquid carbon dioxide) can be exemplified.

Further, in the present invention, the composition A is supplied to the foaming machine in order to improve the dispersibility of the powdery flame retardant in the sprayed part when sprayed on the construction object. The pressure at that time (supply pressure) is 3 to 10 MPa, preferably 4 to 9 MPa. If the supply pressure of the composition A to the foaming machine is less than 3 MPa, it may not be possible to perform sufficient spraying, while if the supply pressure exceeds 10 MPa, a large load is applied to the foaming machine, causing failure. May trigger.

Furthermore, in the present invention, advantageously, according to a blowing foaming method, 1) a lower blowing layer made of a polyurethane foam having a thickness of 2 to 10 mm is formed on a construction object, and then 2) such a lower blowing layer. A polyurethane foam is manufactured by forming one or more polyurethane foam layers having a thickness of 30 mm or less thereon. In such a method, the formation of the underblown layer improves the adhesion between the construction object and the polyurethane foam, and the reaction heat during the formation of the underblown layer effectively reduces the construction surface temperature of the construction object. Therefore, even in a low temperature environment, it is possible to produce a polyurethane foam having excellent flame retardancy and a uniform density distribution. Further, by forming a polyurethane foam layer having a thickness of 30 mm or less on the lower blown layer, it is possible to advantageously manufacture a polyurethane foam having less warpage or deformation and less cracks or cracks as a whole.

Hereinafter, some examples of the present invention will be shown to clarify the characteristics of the present invention more specifically, but the present invention is subject to any restrictions by the description of such examples. Not to mention that. Further, in addition to the following embodiments, in addition to the specific description described above, the present invention includes various modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that modifications, improvements, etc. may be made. The% and parts shown below are based on mass.

First, each component is contained in the ratios shown in Tables 1 to 5 below (however, liquid CO ₂ and liquid CO ₂ and HFO-1234ze represented as “liquid CO ₂ +HFO-1234ze” in the table). And a composition B containing a polyol as a main component, and a composition B consisting of polyisocyanate (Polymeric MDI, manufactured by Wanka Kagaku Japan Co., Ltd., product name: Wannate PM-130), Got ready. The raw materials used in the preparation of the composition A are as follows. Further, the viscosity at 20° C. was measured for each of the prepared compositions A, and the results are shown in Tables 1 to 5, while the viscosity at 20° C. of the composition B made of polymeric MDI was measured to be 200 mPa· was s. The viscosity of each composition was measured according to JIS K7117-1:1999 using a Brookfield type rotational viscometer type B under a test temperature of 20°C.
・Polyol: terephthalic acid type polyester polyol
(Kawasaki Kasei Co., Ltd., product name: RFK505, specific gravity: 1.23)
・Polyol: terephthalic acid type polyester polyol
(Kawasaki Kasei Co., Ltd., product name: RLK035, specific gravity: 1.2)
・Foam stabilizer: Silicone-based foam stabilizer
(Product made by Toray Dow Corning Co., Ltd., product name: SH-193)
・Flame retardant: Red phosphorus
(Product name: Nova Red 120, manufactured by Rin Kagaku Kogyo Co., Ltd., average particle size: 25 μm, with surface coating treatment, specific gravity: 2.34)
・Flame retardant: Red phosphorus
(Product name: Nova Excel 140, manufactured by Rin Kagaku Kogyo Co., Ltd., average particle size: 30 μm, with surface coating treatment, specific gravity: 2.34)
・Flame retardant: Phosphate-containing flame retardant
(Ammonium dihydrogen phosphate, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., average particle diameter: 5 μm, specific gravity: 1.9)
・Flame retardant: Flame retardant containing stannate
(Zinc stannate, manufactured by Nippon Light Metal Co., Ltd., product name: Flamtard S, average particle diameter: 2 μm, specific gravity: 3.9)
・Flame retardant: boric acid-containing flame retardant
(Zinc borate, manufactured by Mizusawa Chemical Co., Ltd., product name: ALCANEX FR-100, average particle diameter: 4 μm, specific gravity: 2.8)
・Flame retardant: Metal hydroxide
(Aluminum hydroxide, manufactured by Nippon Light Metal Co., Ltd., product name: B1403, average particle diameter: 2 μm, specific gravity: 2.42)
・Flame retardant: Metal hydroxide
(Aluminum hydroxide, manufactured by Nippon Light Metal Co., Ltd., product name: SB93, average particle diameter: 105 μm, specific gravity: 2.42)
・Flame retardant: Zinc oxide
(Sakai Chemical Industry Co., Ltd., average particle size: 0.75 μm, specific gravity: 5.6)
・Flame retardant: Phosphate ester
[TMCPP: tris(1-chloro-2-propyl)phosphate, manufactured by Daihachi Kagaku Kogyo Co., Ltd., liquid]
・Flame retardant: Flame retardant containing bromine
(Hexabromobenzene, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., liquid)
・Trimerization catalyst: quaternary ammonium salt
(Kao Corporation, product name: Kaorizer No. 420)
-Resinization catalyst: N,N-dicyclohexylmethylamine
(Evonik Japan KK, product name: Polycat 12)
Blowing agent: HCFO-1233zd
(Honeywell, 1-chloro-3,3,3-trifluoropropene)
Blowing agent: HFO-1336mzz
(1,1,1,4,4,4-hexafluoro-2-butene manufactured by Chemours)
・Foaming agent: HFC245fa
(Central Glass Co., Ltd., 1,1,1,3,3-pentafluoropropane)
・Foaming agent: HFC365mfc
(1,1,1,3,3-pentafluorobutane manufactured by SOLVAY Co., Ltd.)
Blowing agent: liquid CO ₂ +HFO-1234ze (mixture)
(Tokyo high Yamazaki Co., liquid _{CO 2: HFO-1234ze = 3} : 7 ( weight ratio))

-Stirring treatment of composition A-
Each of the prepared Compositions A was stirred using a stirrer at the rotation speeds and stirring times shown in Tables 1 to 5.

-Production of Polyurethane Foam (Examples 1-17, Comparative Examples 1-8)-
The composition A and the composition B (polymeric MDI) were used at a volume ratio of 1:1 and mixed by stirring with an in-situ foaming spraying machine (trade name: A-25, manufactured by Graco) to prepare a foaming stock solution. , The surface of a flexible board (910 mm x 910 mm), which is a frame, is sprayed once downward and twice upward, and then reacted on the board to foam and cure, so that the lower blowing layer is 5 mm or less. And a foam layer (total thickness: about 60 mm) made of rigid polyurethane foam in which each of the two top blowing layers was 30 mm or less was formed (Examples 1 to 17 and Comparative Examples 1 to 8). The foam layers used in the evaluation of "foam processability" and "flame retardancy" described in detail below were both formed using the composition A within 1 hour after the end of the stirring treatment. ..

-Production of polyurethane foam (Examples 18 and 19)-
First, the composition A and the composition B (polymeric MDI) were used to prepare a composition using an in-situ foaming spraying device (Asahi Organic Materials Co., Ltd., product name: AYK-1000 series) equipped with a liquefied carbon dioxide supply device. Liquid carbon dioxide in the proportions shown in Table 3 or a mixture of liquid carbon dioxide and HFO-1234ze was supplied to A, and after mixing, the obtained liquid carbon dioxide (liquid CO ₂ ) or the like was added. The composition A containing the composition B was contact-mixed with the composition B in a volume ratio of 1:1. Continuously from such contact mixing, the surface of the flexible board (910 mm × 910 mm) which is the body is sprayed once downward and twice upward, and reacted on such a board to foam and cure. A foam layer (total thickness: about 60 mm) made of rigid polyurethane foam having a lower blow layer of 5 mm or less and two upper blow layers of 30 mm or less was formed (Example 18, Example 19). ). The foam layers used in the evaluation of "foam processability" and "flame retardancy" described in detail below were both formed using the composition A within 1 hour after the end of the stirring treatment. ..

Then, using each polyurethane foam thus obtained as a sample, foam processability, particle dispersibility of a powdery flame retardant and flame retardancy were evaluated. The measurement and evaluation were performed according to the following procedures. The obtained results are shown in Tables 1 to 5 below. In Table 5, “Blown impossible” in Comparative Example 9 means that sufficient polyurethane foam was not formed even though an attempt was made to produce a polyurethane foam by spraying according to the above procedure.

-Evaluation of foam processability-
Using a polyurethane foam having a skin layer (surface layer) formed by spraying on the flexible board, the end of the polyurethane foam protruding from the flexible board is cut with a cutter knife along the peripheral edge of the flexible board. Then, the processability of the polyurethane foam is evaluated according to the following criteria by the touch feeling at that time.
⊚: Almost no force is required for cutting, and the cut surface is good.
◯: Some power is required for cutting, but the cut surface is good.
Δ: A large amount of force is required for cutting, and the cut surface has some difficulties.
X: It is difficult to cut with a cutter knife and can be cut with a saw, and there is a problem in the cut surface.

-Evaluation of dispersibility of powdery flame retardant-
The composition A was stirred at the rotation speeds and stirring times shown in Tables 1 to 5, 1) the composition A within 1 hour after the completion of the stirring treatment, and 2) at room temperature for 5 hours after the completion of the stirring treatment. Composition A was allowed to stand, 3) Polyurethane foam was sprayed using each of the compositions A left at room temperature for 10 hours after the completion of the stirring treatment. The cross sections of the test pieces cut out from the various polyurethane foams thus obtained were observed with an optical microscope, and the number of powdery flame retardant particles in the range of 500 μm×500 μm was examined at 10 locations. Then, an average value of the number of particles aggregated at 10 points was calculated, and the average value was compared with each of the number of particles at 10 points and evaluated according to the following criteria. In Tables 1 to 5 below, 1) the evaluation result of the polyurethane foam obtained by using the composition A within 1 hour after the completion of the stirring treatment is "dispersion of powdery flame retardant (within 1 hour)". Column, 2) shows the evaluation results of the polyurethane foam obtained by using the composition A that was left standing at room temperature for 5 hours after the end of the stirring treatment, in the column of "Dispersibility of powdery flame retardant (after 5 hours)". 3) In the column of "Dispersibility of powdery flame retardant (after 10 hours)", the evaluation results of the polyurethane foam obtained by using the composition A that was allowed to stand at room temperature for 10 hours after the completion of the stirring treatment, respectively. Show.
⊚: The number of particles at 10 locations is within ±60% of the average value.
◯: The number of particles at 10 locations is within ±80% of the average value.
Δ: The number of particles at 10 locations is within ±100% of the average value.
X: The number of particles at 10 locations exceeds ±100% of the average value.

-Evaluation of flame retardancy-
According to the flammability measuring method specified in JIS A9526:2015, a test piece of 50 mm×150 mm×13 mm was cut out from each of the obtained polyurethane foams, and one end of this test piece was equipped with a fish tail lamp Bunsen. Burn with a burner for 60 seconds, and measure the time to extinction and the burning distance, respectively. The flame retardancy of the measurement results is evaluated according to the following criteria. In addition, the evaluation of ◎ and ○ is passed.
A: The burning distance is less than 30 mm and the burning time is less than 60 seconds.
Good: The burning distance is less than 60 mm and the burning time is less than 120 seconds.
Δ: Burning distance is 60 mm or more or burning time is 120 seconds or more.
X: The burning distance is 60 mm or more and the burning time is 120 seconds or more.

As is clear from the results shown in Tables 1 to 3, all of the polyurethane foams (Examples 1 to 19) produced according to the production method of the present invention have foam processability and flame retardancy. Is confirmed to be excellent. Further, even in the polyurethane foam obtained by using the composition A after 10 hours from the stirring treatment, it is recognized that the powdery flame retardant is allowed to be present inside the foam without uneven distribution. In that case, once the composition A is subjected to the stirring treatment, it is possible to produce a polyurethane foam having excellent flame retardancy and having a uniform density distribution without stirring for a long time. It will be confirmed.

On the other hand, as is clear from the results of Tables 4 and 5, the composition A liquid was sprayed and foamed without stirring, and the stirring was performed for a shorter stirring time than the time specified in the present invention. In the polyurethane foams obtained by using the composition A (Comparative Examples 1 to 7), the dispersibility of the powdery flame retardant is poor and there are problems in foam processability and flame retardancy. Is confirmed. Further, in the polyurethane foam (Comparative Example 7) containing the flame retardant having an average particle size exceeding the range of the present invention, the dispersibility of the powdery flame retardant in the composition A was It cannot be maintained, and it is further recognized that the foam processability and flame retardancy are also adversely affected.

Claims (10)

When a polyurethane foam is produced according to a blowing foaming method using a composition A containing a polyol as a main component and a powdery flame retardant and a composition B containing a polyisocyanate as a main component,
The average particle diameter of the powdery flame retardant is 50 μm or less,
The composition A having a viscosity of 100 to 2000 mPa·s at 20° C. is stirred with a stirrer at a rotation speed of 800 to 2000 rpm for 10 minutes or more, and then the blowing foaming method is performed.
A method for producing a polyurethane foam, comprising: The polyurethane foam according to claim 1, wherein the powdery flame retardant is contained in the composition A in a ratio of 1 to 70 parts by mass with respect to 100 parts by mass of the polyol in the composition A. Manufacturing method. The method for producing a polyurethane foam according to claim 1 or 2, wherein the powdery flame retardant is surface-treated with an inorganic material and/or an organic material. The method for producing a polyurethane foam according to any one of claims 1 to 3, wherein the powdery flame retardant has a specific gravity of 1.0 to 5.0. The method for producing a polyurethane foam according to any one of claims 1 to 4, wherein the powdery flame retardant has a specific gravity of 1 to 5 times the specific gravity of the composition A. The method for producing a polyurethane foam according to any one of claims 1 to 5, wherein the blowing foaming method is performed while circulating the composition A in a storage tank. The method for producing a polyurethane foam according to any one of claims 1 to 6, wherein a supply pressure of the composition A to the foaming machine in the blowing foaming method is 3 to 10 MPa. The said blowing foaming method is implemented by mixing the said composition A and the said composition B with a foaming machine, and spraying this mixture on a construction target object. Method for producing polyurethane foam. The blowing foaming method is carried out by mixing a foaming agent which becomes a gas at room temperature with a foaming machine together with the composition A and the composition B, and spraying the mixture onto a construction object. 7. The method for producing a polyurethane foam according to any one of 7. According to the blowing foaming method, 1) a lower blowing layer made of a polyurethane foam having a thickness of 2 to 10 mm is formed on a construction object, and 2) a polyurethane foam layer having a thickness of 30 mm or less is formed on the lower blowing layer. Forming one or more layers,
The method for producing a polyurethane foam according to any one of claims 1 to 9, wherein