JP2022019869A - Method for producing polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyurethane foam which can be advantageous for a polyurethane foam having excellent flame retardancy and a uniform density distribution.

SOLUTION: In producing a polyurethane foam by mixing and reacting a composition A mainly comprising a polyol and a composition B mainly comprising a polyisocyanate, followed by foaming and curing to produce a polyurethane foam, there is produced a polyurethane foam by incorporating a predetermined amount of a powdery flame retardant having a specific gravity of 1.0 to 5.0 in the composition A and/or the composition B, using a composition A of which viscosity at 20°C is adjusted to 50 to 2000 mPa s and a composition B of which viscosity at 20°C is adjusted to 50 to 1500 mPa s and adding a foaming agent I composed of carbon dioxide in a critical state, a subcritical state and a liquid state to the composition A and/or the composition B in the polyurethane production site to produce a polyurethane foam after such addition according to a blow-foaming method.

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

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.

Conventionally, polyurethane foam has been used mainly as a heat insulating material for heat insulating materials such as interior and exterior wall materials for buildings, heat insulation of panels, metal siding, electric refrigerators, etc. by utilizing its excellent heat insulating properties, adhesiveness, and light weight. It is used for heat insulation, heat insulation of building walls, ceilings, roofs, etc. of buildings, apartments, frozen warehouses, etc. and prevention of dew condensation, heat insulation of infusion pipes, etc. It is also practically used as a reinforcing material for the case. Further, such a polyurethane foam is generally composed of a polyol compounding solution (premixed solution) in which a polyol is mixed with a foaming agent and, if necessary, various auxiliaries such as a catalyst, a foam stabilizer and a flame retardant. A and the 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 obtained by a slab foaming method, an injection foaming method, or the like. It is manufactured by foaming and curing by a method such as a spray foaming method, a laminated continuous foaming method, a lightweight filling method, and an injection backfilling method.

By the way, since the polyurethane foam formed as described above is required to have flame retardancy due to its use, a flame retardant is added as described in Patent Documents 1 to 3. It is known that flame retardancy is imparted to the obtained polyurethane foam by using the above-mentioned polyol component.

However, it is difficult to manufacture polyurethane foam by spraying it from the spray gun head of the on-site foaming machine to the target adherend (structure), foaming and curing it according to the spray foaming method (spray foaming method). The use of flame retardants may cause the following problems. That is, 1) the powdery flame retardant may hinder the progress of the urethane reaction, and 2) the specific gravity of the powdery flame retardant is generally larger than the specific density of the entire composition, and is in the composition. Due to the low dispersibility of the powdery flame retardant, etc., the flame retardant is present in a biased state in the finally obtained polyurethane foam, and as a result, the polyurethane foam having a biased density distribution. The problem of being manufactured is inherent.

Japanese Unexamined Patent Publication No. 2002-47325 Japanese Unexamined Patent Publication No. 2015-193839 Japanese Unexamined Patent Publication No. 2018-100405

Here, the present invention has been made in the background of such circumstances, and the problem to be solved thereof is a method of spraying and foaming a polyurethane foam having excellent flame retardancy and a uniform density distribution. It is an object of the present invention to provide a method for producing a polyurethane foam which can be advantageously produced according to the above.

The present invention can be suitably carried out in various aspects as listed below in order to solve the above-mentioned problems. It is understood that the aspects or technical features of the present invention are not limited to those described below and can be recognized based on the invention idea that can be grasped from the description of the specification. Should be.

(1) When producing a polyurethane foam by mixing and reacting a composition A containing a polyol as a main component and a composition B containing a polyisocyanate as a main component to foam and cure them.
The powdery flame retardant having a specific gravity of 1.0 to 5.0 is used in the composition A and / or 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. It is contained in the composition B,
The composition A prepared to have a viscosity at 20 ° C. of 50 to 2000 mPa · s and the composition B prepared to have a viscosity at 20 ° C. of 50 to 1500 mPa · s were used.
At the production site of the polyurethane foam, a foaming agent I composed of critical, subcritical or liquid carbon dioxide is added to the composition A and / or the composition B, and after the addition, according to the spray foaming method. The polyurethane foam is manufactured,
A method for manufacturing polyurethane foam.
(2) The method for producing a polyurethane foam according to the above aspect (1), wherein the powdery flame retardant has an average particle size of 50 μm or less.
(3) The embodiment in which the powdery flame retardant is contained in the composition A, and the specific gravity of the powdery flame retardant is 1 times or more and 5 times or less the specific gravity of the composition A. (1) Or the method for producing a polyurethane foam according to the above aspect (2).
(4) The powdery flame retardant is at least one selected from red phosphorus, phosphate-containing flame retardant, stannate-containing flame retardant, borane-containing flame retardant, metal hydroxide and metal oxide. The method for producing a polyurethane foam according to any one of the above-mentioned aspects (1) to (3).
(5) The polyurethane form according to any one of the embodiments (1) to (4), wherein the liquid flame retardant is further contained in the composition A and / or the composition B. Production method.
(6) The method for producing a polyurethane foam according to the above aspect (5), wherein the liquid flame retardant is at least one selected from a phosphoric acid ester and a bromine-containing flame retardant.
(7) One of the above-mentioned embodiments (1) to (6), wherein the powdery flame retardant contains red phosphorus as an essential component and contains at least one flame retardant other than red phosphorus. The method for manufacturing a polyurethane foam described in 1.
(8) The foaming agent II composed of at least one of water, hydrocarbon, hydrofluorocarbon and halogenated olefin is at least one of the composition A, the composition B and the foaming agent I. The method for producing a polyurethane foam according to any one of the above-mentioned aspects (1) to (7), which is further contained.
(9) The polyuretan foam according to any one of the above embodiments (1) to (8), wherein a polyurethane form having a difference between the total density and the core density of 0.1 to 12 kg / m ³ can be obtained. Manufacturing method.
(10) Polyuretan foam having a total calorific value of 8 MJ / m ² or less after 20 minutes when heated at a radiant heat intensity of 50 kW / m ² in accordance with the test method specified in ISO-5660. The method for producing a polyurethane foam according to any one of the above-mentioned aspects (1) to (9).

According to such a method for producing a polyurethane foam according to the present invention, the effects listed below can be advantageously enjoyed.
(1) A mixture of composition A and composition B due to effective foaming of the foaming agent I (critical, subcritical or liquid carbon dioxide) from the start to the end of the reaction between the polyol and the polyisocyanate. The dispersed state of the powdery flame retardant in the (reactant) is well maintained, in other words, the powdery flame retardant is uniformly present in the mixture (reactant) without being unevenly distributed. Therefore, the obtained polyurethane foam exhibits excellent flame retardancy due to the flame retardant and has a uniform density distribution.
(2) The polyurethane foam obtained in accordance with the present invention in which the powdered flame retardant is well dispersed and has a uniform density distribution has moderately low elasticity and surface hardness of the foam, and the entire foam has flexibility. Because of its excellent properties, it has excellent workability such as cutting and cutting, and it is easy to perform cutting work that is carried out after the foam is manufactured by the spray foaming method.
(3) In winter when the environmental temperature is low, when two-layer spraying (two-stage spraying) is performed by applying the present invention, the first layer foam (foam formed by the first spraying) and the second layer The final difference is that the difference in density between the foam of the eyes (the foam formed by the second spray) is small and therefore the generation of shrinkage differences between those layers is effectively suppressed. The polyurethane foam obtained in the above form is one in which the occurrence of warpage is suppressed as a whole. Further, even if the polyurethane foam is produced by the spray foaming method in a low temperature environment according to the production method of the present invention, the above-mentioned polyuretan foam having excellent processability can be obtained.

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 obtain the desired polyurethane foam. However, various known polyol compounds that react with polyisocyanate to produce polyurethane are used alone or as appropriate in the polyols that are the main constituents of the composition A used therein. It is being used in combination with. Then, a polyether polyol, a polyester polyol, or the like is preferably used there. Of course, in addition to these polyols, it goes without saying that various known polyol compounds such as polyolefin-based polyols, acrylic-based polyols, polymer polyols and the like can be used alone or in combination as appropriate. ..

Specifically, among such polyols, the polyether polyol is used as an initiator for at least one of polyhydric alcohols, saccharides, aliphatic amines, aromatic amines, phenols, Mannig condensates and the like, and alkylene oxides. It is obtained by reacting. Therefore, examples of the alkylene oxide include propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, ethylene oxide and the like. In addition, polyhydric alcohols as initiators include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, pentaerythritol and the like, and sugars include sucrose, dextrose, sorbitol and the like. Further, as the aliphatic amine, there are alkanolamines such as diethanolamine and triethanolamine, polyamines such as ethylenediamine and the like, and as aromatic amines, various methyl substituents of phenylenediamine collectively referred to as tolylenediamine. Other examples include derivatives in which substituents such as methyl, ethyl, acetyl and benzoyl are introduced into the amino group, 4,4'-diaminodiphenylmethane, p-phenylenediamine, o-phenylenediamine, naphthalenediamine and the like. Further, examples of the phenols include bisphenol A, novolak type phenol resin and the like. In addition, examples of the Mannich condensation product include a Mannich condensation product obtained by subjecting phenols, aldehydes, and alkanolamines to a Mannich condensation reaction.

Examples of the polyester polyol include a polyhydric alcohol-polyvalent carboxylic acid condensation system polyol, a cyclic ester ring-opening polymerization system polyol, and the like. Here, as the polyhydric alcohol, those described above can be used, and in particular, dihydric alcohols are preferably used. Examples of the polyvalent carboxylic 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 anhydrides thereof. Further, as the cyclic ester, ε-caprolactone or the like will be used.

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 a polyester. It is also effective to combine two or more types of polyols. The phthalic acid-based polyester polyol is a polyol composed of a condensate of phthalic acid, terephthalic acid, isophthalic acid and their anhydrides and dihydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol and dipropylene glycol. It means. When such a phthalic acid-based polyester polyol is used, even when on-site foaming is performed at a low temperature (about -10 ° C to 5 ° C), the generated foam is less likely to be peeled off from the building frame or the like, and further on-site. There is an advantage that it is possible to obtain a rigid polyurethane foam having flexibility to a extent 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 is characterized by having excellent storage stability.

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

On the other hand, the polyisocyanate, which is the main component of the composition B, is blended with the composition A and reacts with the polyol in the composition A to form a polyurethane (resin), which is in the molecule. It is an organic isocyanate compound having two or more isocyanate groups (NCO groups). Aromatic polyisocyanates such as dimethyldiphenylmethane diisocyanate and triphenylmethane triisocyanate, aliphatic polyisocyanates such as methylene diisocyanate, ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate and hexamethylene diisocyanate, isophorone diisocyanate, cyclohexylene diisocyanate and methylcyclohexylene. Examples thereof include alicyclic polyisocyanates such as diisocyanate, dicyclohexylmethanediisocyanate, and dimethyldicyclohexylmethanediisocyanate, urethane prepolymers having an isocyanate group at the molecular terminal, isocyanurate-modified polyisocyanates, and carbodiimide-modified products. These polyisocyanate compounds may be used alone or in combination of two or more. In general, polymethylene polyphenylene polyisocyanate (polymeric MDI) is preferably used from the viewpoint of reactivity, economy, handleability and the like.

The ratio of the polyisocyanate in the composition B to the polyol in the composition A described above will be appropriately determined depending on the type of foam to be formed (for example, polyurethane or polyisocyanurate). However, in general, the NCO / OH index (equivalent ratio) indicating 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 decided appropriately so as to be within the range of the degree.

In the present invention, the above-mentioned composition A containing a polyol as a main component and the composition B containing a polyisocyanate as a main component are mixed and reacted, and are foamed and cured by a foaming agent. As a result, a polyurethane foam is formed, and a catalyst is generally used in the reaction between the composition A and the composition B. In the present invention, the composition A preferably contains a trimerization catalyst, in other words, a catalyst (isocyanurate-forming catalyst) that reacts with an isocyanate group of polyisocyanate to tritrate and promote the formation of an isocyanurate ring. It will be contained. As the trimerization catalyst, various known catalysts can be appropriately selected and used, but a quaternary ammonium salt, potassium octylate, potassium 2-ethylhexanoate, sodium acetate are preferable. Carboxylic acid alkali metal salts such as; nitrogen-containing aromatic compounds such as tris (dimethylaminomethyl) phenol, 2,4-bis (dimethylaminomethyl) phenol, tris (dimethylaminopropyl) hexahydrotriazine; trimethylammonium salt, triethyl Examples thereof include tertiary ammonium salts such as ammonium salts and triphenylammonium salts. Of these, it is preferable to use a quaternary ammonium salt from the viewpoint of improving flame retardancy, and in particular, using a quaternary ammonium salt and a carboxylic acid alkali metal salt in combination is further flame retardant. Especially preferable from the viewpoint of improvement.

Examples of the quaternary ammonium salt advantageously used here include tetramethylammonium, methyltriethylammonium, ethyltrimethylammonium, propyltrimethylammonium, butyltrimethylammonium, pentyltrimethylammonium, hexyltrimethylammonium, heptyltrimethylammonium, and octyltrimethylammonium. Aliphatic ammonium such as nonyltrimethylammonium, decyltrimethylammonium, undecyltrimethylammonium, dodecyltrimethylammonium, tridecyltrimethylammonium, tetradecyltrimethylammonium, heptadecyltrimethylammonium, hexadecyltrimethylammonium, heptadecyltrimethylammonium, octadecyltrimethylammonium, etc. Compounds, hydroxyammonium compounds such as (2-hydroxypropyl) trimethylammonium, hydroxyethyltrimethylammonium, trimethylaminoethoxyethanol, hydroxyethyl-2-hydroxypropyldimethylammonium, 1-methyl-1-azania-4-azabicyclo [2, 2,2] Examples thereof include alicyclic ammonium compounds such as octanium, 1,1-dimethyl-4-methylpiperidinium, 1-methylmorpholinium, and 1-methylpiperidinium. Among these, tetramethylammonium, methyltriethylammonium, ethyltrimethylammonium, butyltrimethylammonium, hexyltrimethylammonium, octyltrimethylammonium, decyltrimethylammonium, dodecyltrimethylammonium, because of their excellent catalytic activity and industrial availability, 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 inorganic acid group constituting such a quaternary ammonium salt include formic acid group, acetic acid group, octyl acid group, oxalic acid group, malonic acid group, succinic acid group and 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, phosphoric acid ester group, etc. Examples thereof include inorganic acid groups such as halogen groups, hydroxyl groups, hydrogen carbonate groups and carbonate groups. Among these, a formic acid group, an acetic acid group, an octylate group, a methyl carbonate group, a halogen group, a hydroxyl group, a hydrogen carbonate group and a carbonic acid group are preferable because they have excellent catalytic activity and are industrially available.

Further, as a catalyst composed of such a quaternary ammonium salt, various catalysts are commercially available, and for example, U-CAT 18X, U-CAT 2313 (manufactured by Sun Appro Co., Ltd.), Kaorizer No. 410, Kao Riser No. 420 (manufactured by Kao Corporation) and the like can be mentioned.

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 exert the function as the catalyst. It will be selected within the range of 1 to 10 parts by mass, preferably 0.5 to 8 parts by mass, and more preferably 1 to 6 parts by mass. If the amount of the trimerization catalyst used is less than 0.1 parts by mass, the trimerization of polyisocyanate cannot be sufficiently realized, and therefore it becomes difficult to sufficiently achieve the effect of improving flame retardancy. On the other hand, if the amount exceeds 10 parts by mass, the reaction proceeds too much and the solidification becomes faster, which makes spraying work difficult.

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

The amount of the resinification catalyst used is 0.1 to 10 parts by mass, preferably 0, with respect to 100 parts by mass of the entire polyol in the composition A in order to effectively exert its function as a catalyst. It will be selected within the range of .5 to 8 parts by mass, more preferably 1 to 6 parts by mass. If the amount of this resinification catalyst used is less than 0.1 parts by mass, the obtained foam may become sticky, dust or the like may adhere to the resin, resulting in a poor appearance. In the spray foaming operation, the floor or the like may be used. Since the droplets adhering to the salt become sticky, there is a problem that workability deteriorates. On the other hand, if the amount exceeds 10 parts by mass, heat generation increases during the resinification reaction, and the appearance is abnormal such as yellowing of the foam. The catalyst containing the quaternary ammonium salt contained in the droplets generated during foaming may worsen the work environment at the work site where the spraying work is performed.

On the other hand, in the present invention, with respect to either one of the above-mentioned composition A containing a polyol as a main component or the composition B containing a polyisocyanate as a main component, or both of the composition A and the composition B. A powdery flame retardant is added. In the present invention, the amount of the powdery flame retardant used (when added to both the composition A and the composition B, the total amount added to each composition) is the amount of the polyol in the composition A. It is determined within the range of 1 to 70 parts by mass, preferably 10 to 60 parts by mass, and more preferably 20 to 55 parts by mass with respect to 100 parts by mass. If the amount of the powdery flame retardant added is too small, the obtained polyurethane foam may not exhibit sufficient flame retardancy, and if the amount added is too large, the composition to which it is added may not be exhibited. In addition to increasing the viscosity of the object and causing problems such as poor stirring, it may also cause problems such as a decrease in workability and a problem such as the polyurethane foam becoming more flammable.

Here, in the production method according to the present invention, the average particle size of the powdery flame retardant used is 50 μm or less, preferably 0.1 to 50 μm, more preferably 0.5 to 40 μm, still more preferably 1 to 35 μm. be. A powdery flame retardant having an average particle size of 50 μm or less is used, and the viscosity of each of the composition A containing a polyol as a main component and the composition B containing a polyisocyanate as a main component is within a predetermined range. By using the prepared one, the sedimentation rate of the powdery flame retardant in the composition (and in the mixture of the two compositions) is more effectively slowed down, and the powdery flame retardant is in a good dispersed state. Is maintained for a longer period of time, so that the effect of the present invention can be enjoyed more advantageously.

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 improve the dispersed state of the powdery flame retardant, more preferably. It is preferably 1.2 to 4.5, and more preferably 1.6 to 4.0.

Further, when the powdery flame retardant is contained in the composition A containing a polyol as a main component and used, the specific gravity of the powdery flame retardant is 1 times or more and 5 times or less the specific gravity of the composition A. It is preferably 1 time or more, 4.5 times or less, and more preferably 1.2 times or more and 4 times or less. In the composition A, the specific gravity of the powdery flame retardant is preferably 1 times or more the specific gravity of the composition A so that the powdery flame retardant does not float. On the other hand, by reducing the difference in specific densities between the powdery flame retardant and the composition A, the sedimentation rate of the powdery flame retardant in the composition A becomes slower, so that the specific gravity of the powdery flame retardant is the composition A. It is preferably 5 times or less of the specific gravity.

In the method for producing a polyurethane foam according to the present invention, any conventionally known flame retardant in the form of powder can be used, and usually, it is appropriately selected from commercially available products and used. It will be. Examples of the powdery flame retardant that can be used in the present invention include red phosphorus, a phosphate-containing flame retardant, a stannate-containing flame retardant, a boron-containing flame retardant, a metal hydroxide, a metal oxide, and the like. One or more of these can be selected and added to composition A and / or composition B.

-Red phosphorus-
Any conventionally known red phosphorus can be used, but in the present invention, coated red phosphorus is advantageously used among the known red phosphorus from the viewpoint of safety and ease of handling. Coated red phosphorus is red phosphorus that has been surface-treated with an inorganic substance and / or an organic substance, and commercially available coated red phosphorus includes Novaled (trade name, manufactured by Rinkagaku Kogyo Co., Ltd.) and Nova. Excel (trade name, manufactured by Rinkagaku Kogyo Co., Ltd.), Hishigard (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. Therefore, the red phosphorus component is 80% or more, preferably 80 to 99%. Coated red phosphorus, preferably 90-98%, is advantageously used.

-Phosphate-containing flame retardant-
The phosphate-containing flame retardant is one containing phosphate and having 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, at least one metal selected from the above-mentioned various phosphoric acids, metals of Group IA to IVB of the Periodic Table, ammonia, aliphatic amines, and aromatic amines or compounds thereof. Phosphate consisting of the salt of and can be mentioned. Examples of the metals of Group IA to Group 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, and examples of the aromatic amine include pyridine, triazine, melamine and ammonium. The phosphate-containing flame retardant used in the present invention may be treated with a silane coupling agent, coated with a melamine resin, or other known water resistance improving treatment, and may be melamine, pentaerythritol, or the like. A known foaming aid 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 for example, ammonium salts such as ammonium phosphate, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate, monosodium phosphate, disodium phosphate, and trisodium phosphate. , Sodium phosphate, disodium phosphite, sodium salts such as sodium hypophosphite, monopotassium phosphate, dipotassium phosphate, tripotassium phosphate, monopotassium phosphite, dipotassium phosphite, Potassium salts such as potassium hypophosphite, monolithium phosphate, dilithium phosphate, trilithium phosphate, monolithium phosphate, dilithium phosphite, lithium salts such as lithium hypophosphite, diphosphate Barium salts such as barium hydrogen, barium hydrogen phosphate, tribarium phosphate, barium hypophosphite, magnesium monohydrogen phosphate, magnesium hydrogen phosphate, trimagnesium phosphate, magnesium salts such as magnesium hypophosphite, phosphorus Calcium salts such as calcium dihydrogen acid, calcium hydrogen phosphate, tricalcium phosphate, calcium hypophosphite, zinc salts such as zinc phosphate, zinc phosphite, zinc hypophosphite and the like can be mentioned.

Further, 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, one or more of the conventionally known phosphate-containing flame retardants such as those described above can be appropriately selected and used. Among the above-mentioned phosphates, monophosphate is advantageously used and ammonium dihydrogen phosphate is more preferably used in that it is excellent in self-extinguishing property.

-Stannate-containing flame retardant-
The stannate-containing flame retardant is a flame retardant containing a tin acid metal salt. Here, examples of the metal salt of tin contained in the flame retardant containing stannate include zinc tinate, barium tinate, sodium tinate, potassium tintin, cobalt tintate, magnesium tint, and the like. Among them, 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. Specifically, examples of the boron oxide include diboron trioxide, boron trioxide, diboron dioxide, tetraboron trioxide, and tetraboron pentoxide. Examples of borates include alkali metals, alkaline earth metals, elements of Groups 4, 12, and 13 of the Periodic Table, and ammonium borates. More specifically, alkali metal borate salts such as lithium borate, sodium borate, potassium borate, and cesium borate; alkaline earth metal borate salts such as magnesium borate, calcium borate, and barium borate; Examples thereof include zirconium borate, zinc borate, aluminum borate, and ammonium borate.

In the present invention, one or more of the conventionally known boron-containing flame retardants such as those described above can be appropriately selected and used. 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 a flame retardant include magnesium hydroxide, calcium hydroxide, aluminum hydroxide, iron hydroxide, nickel hydroxide, zirconium hydroxide, titanium hydroxide, and zinc hydroxide. , Copper hydroxide, vanadium hydroxide, tin hydroxide and the like. One or more of these known substances 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 more of these known substances are appropriately selected and used.

Further, in the production method of the present invention, it is also possible to use a liquid flame retardant together with the above-mentioned powdery flame retardant. By using the powdery flame retardant and the liquid flame retardant in combination, the flame retardancy of the finally obtained polyurethane foam can be further improved, and the viscosity of the composition A and the composition B can be further improved. 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 monophosphate ester and condensed phosphoric acid ester.

The monophosphoric acid ester is not particularly limited, and is not particularly limited, for example, trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri (2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl. Phosphonate, Tris (isopropylphenyl) Phosphonate, Tris (Phenylphenyl) Phosphonate, Trinaphthyl Phosphonate, Cresyldiphenyl Phosphonate, Xylenyldiphenyl Phosphonate, Diphenyl (2-Ethylhexyl) Phosphonate, Di (Isopropylphenyl) Phosphonate, Monoisodecyl Phosphonate, 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, melamine phosphate, dimelamine phosphate, melamine pyrophosphate, triphenyl phosphate. Oxide, tricresylphosphinoxide, diphenyl methanephosphonate, diethyl phenylphosphonate, resylsinol bis (diphenyl phosphate), bisphenol A bis (diphenyl phosphate), phosphaphenanthrene, tris (β-chloropropyl) phosphate, etc. , Can be mentioned.

The condensed phosphoric acid ester is also not particularly limited, and for example, trialkylpolyphosphate, resorcinolpolyphenyl phosphate, resorcinol poly (di-2,6-kisilyl) phosphate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name). : PX-200), hydroquinonepoly (2,6-kisilyl) phosphate, and condensates thereof can be mentioned. Examples of commercially available condensed phosphate esters other than those described above include resorcinol polyphenyl phosphate (trade name: CR-733S), bisphenol A polycresyl phosphate (trade name: CR-741), and aromatic condensed phosphate ester. (Product name: CR747), resorcinolpolyphenyl phosphate (manufactured by ADEKA, trade name: Adecastab 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 of conventionally known phosphate esters such as the above-mentioned monophosphate ester and condensed phosphate ester can be appropriately selected and used. be. Further, among the above-mentioned monophosphoric acid esters and condensed phosphoric acid esters, monophosphoric acid esters can be used in that they have a high effect of reducing the viscosity in the composition before curing and the effect of reducing the initial calorific value. Preferably, it is more preferred 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 ( Tetrabromophthalimide), monomer organic bromine compounds such as tetrabromobisphenol A; polycarbonate oligomers produced from brominated bisphenol A as raw materials, brominated polycarbonates such as copolymers of the above polycarbonate oligomers and bisphenol A; brominated bisphenols. Brominated epoxy compounds such as diepoxy compounds produced by the reaction of A with epichlorohydrin, monoepoxy compounds obtained by the reaction of brominated phenols with epichlorohydrin; poly (brominated benzyl acrylate); brominated polyphenylene ether; brominated. Condensations of bisphenol A, cyanur chloride and brominated phenol; brominated polystyrene such as brominated (polystyrene), poly (brominated styrene), crosslinked brominated polystyrene; crosslinked or non-crosslinked brominated poly (-methylstyrene), etc. Examples thereof include halogenated bromine compound polymers.

In the present invention, one or more of the conventionally known brominated flame retardants such as those described above can be appropriately selected and used. Among the above-mentioned brominated flame retardants, brominated polystyrene, hexabromobenzene and the like are advantageously used, and hexabromobenzene is more preferably used from the viewpoint of controlling the calorific value at the initial stage of combustion.

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

Then, in the method for producing a polyurethane foam of the present invention, a foaming agent I made of critical, subcritical or liquid carbon dioxide is used as the foaming agent.

Here, critical, subcritical or liquid carbon dioxide (hereinafter abbreviated as liquefied CO ₂ ) is, as is well known, supercritical by pressurizing carbon dioxide gas at a predetermined temperature. It is a state, a subcritical state, or a liquid state. Specifically, liquid carbon dioxide is liquefied under conditions of temperature and pressure above the triple point, and subcritical carbon dioxide has a pressure above the critical pressure and a temperature below the critical temperature. Liquid carbon dioxide, where the pressure is below the critical pressure and the temperature is above the critical temperature, or when the temperature and pressure are below the critical point but close to this. Further, the carbon dioxide in the supercritical state is the carbon dioxide in the fluid state in which both the pressure and the temperature exceed the critical pressure and the critical point above the critical temperature.

Since the above-mentioned liquefied CO _2s exert an effective effervescent action immediately after addition to the composition A or the like, the composition A and the composition are formed 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 obtained polyurethane foam, and further realizes the reduction in density advantageously. .. Further, by using the liquefied CO ₂ type, in the spray foaming method (spray foaming method) described later, the sprayability of the mixture composed of the composition A and the composition B becomes good, and in addition, it is difficult to form a powder. Occurrence of clogging in the spray gun due to the flame retardant is advantageously suppressed. In the present invention, if the amount of liquefied CO ₂ used is too small, the effect of adding the liquefied CO 2 cannot be sufficiently exhibited, and the foaming immediately after spraying by the spray foaming method (spray foaming method) becomes insufficient. Since the density difference between the core layer and the skin layer 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 such liquefied CO ₂ used is too large, the gas (carbon dioxide) generated at the initial stage of the reaction becomes excessive, which adversely affects the foaming characteristics, and during spraying in the spray foaming method (spray foaming method). In addition, problems such as difficulty in obtaining a good foam 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 with respect to 100 parts by mass of the polyol in the composition A, and more preferably 0. It will be within the range of 2 to 3 parts by mass.

Then, such liquefied CO _2s can be obtained in the composition A containing a polyol as a main component by a carbon dioxide supply device as disclosed in, for example, Japanese Patent Application Laid-Open No. 2011-247323 at the manufacturing site of polyurethane foam. It is supplied to the flow path or the flow path of the composition B containing polyisocyanate as a main component and mixed, and contributes to the foaming of polyurethane caused by the reaction between the polyol and the polyisocyanate. Of course, such liquefied CO ₂ is supplied directly to the position where the composition A and the composition B are contacted and mixed, and the liquefied CO ₂ is supplied to both of them. It is also possible to be done.

In the present invention, a foaming agent II composed of at least one of water, hydrocarbon, hydrofluorocarbon and halogenated olefin is preferably used together with the above-mentioned liquefied CO _2s (foaming agent I). Water produces carbon dioxide by reacting with polyisocyanate, and the carbon dioxide functions as a foaming agent. Further, heat of reaction is generated during the reaction between water and polyisocyanate, and the heat can effectively promote the urethanization reaction and the isocyanurate formation reaction, and the compression strength of the obtained polyurethane foam can be increased. There is also the advantage that it can be further enhanced. However, if the amount of such water used becomes too large, the strength will rather decrease. The reason is that 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 in the reaction with water, so that the polyisocyanate in the reaction system decreases. Because. From the above, in the present invention, water as a foaming agent is preferably contained in the composition A containing a polyol as a main component, and the content (usage amount) thereof is 100 parts by mass of the polyol in the composition A. On the other hand, it is desirable that the amount is 5 parts by mass or less, preferably 4 parts by mass or less, more preferably 3 parts by mass or less, and 0.1 parts by mass or more, preferably 0.1 parts by mass or less so that the effect due to the presence of water can be sufficiently exerted. It is desirable that the amount is 0.5 parts by mass or more, more preferably 1 part by mass or more. In addition, such water can be added and blended separately as a blending component for forming the composition A, and can also be added and blended as water contained in other blending components such as a polyol. Water contained by moisture absorption during storage of composition A is also taken into account and will be adjusted to a proportion within the specified range in their total amount.

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 such water. Carbon dioxide is generated by the reaction with polyisocyanate, and this carbon dioxide also contributes to the foaming of polyurethane. Therefore, in the present invention, the carbon dioxide generated by the reaction between the water and the polyisocyanate The composition is such that the organic foaming agent described later has a content of more than 1 mol and 20 mol or less with respect to 1 mol of the total amount of carbon dioxide used as the above-mentioned liquefied CO ₂ class. It is present in the mixture of the substance A and the composition B.

In the present invention, the foaming agent II is an organic foaming agent such as hydrocarbon (HC), hydrofluorocarbon (HFC), hydrofluoroolefin (HFO) or hydrochlorofluoroolefin (instead of or together with water described above). A halogenated olefin (alkene halide) called HCFO) is used. HFC is classified as a chlorofluorocarbon-based foaming agent, and HC, HFO and HCFO are classified as non-chlorofluorocarbon-based foaming agents.

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. Examples thereof include 3,4,5,5,5-decafluoropentane (HFC4310mee), dichloroethane, propyl chloride, isopropyl chloride, butyl chloride, isobutyl chloride, pentyl chloride, isopentyl chloride and the like.

Further, the halogenated olefin (alkene halide) that can be used in the present invention includes those called hydrofluoroolefin (HFO) and hydrochlorofluoroolefin (HCFO), and generally, chlorine and fluorine are used as halogens. It is an unsaturated hydrocarbon derivative having about 2 to 6 carbon atoms, which is bonded and contains. For example, propene, butene, pentene and hexene having 3 to 6 fluorine substituents, including tetrafluoropropene, pentafluoropropene and hexafluorobutene, as well as fluorochloropropene, trifluoromonochloropropene, fluorochlorobutene. Such as unsaturated hydrocarbons having a fluorine substituent and a chlorine substituent, and a mixture of two or more thereof can be mentioned. Examples of the hydrofluoroolefin (HFO) include pentafluoropropene such as 1,2,3,3,3-pentafluoropropene (HFO1225ye), 1,3,3,3-tetrafluoropropene (HFO1234ze), 2, Tetrafluoropropene such as 3,3,3-tetrafluoropropene (HFO1234yf), 1,2,3,3-tetrafluoropropene (HFO1234ye), trifluoropropene 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 (HFO1336mzz). HFO1336), heptafluorobutene isomer (HFO1327), heptafluoropentene isomer (HFO1447), octafluoropentene isomer (HFO1438), nonafluoropentene isomer (HFO1429) and the like can be mentioned. Examples of the hydrochlorofluoroolefin (HCFO) include 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), and the like. 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 can be mentioned.

In particular, the above-mentioned hydrofluoroolefins (HFOs) and hydrochlorofluoroolefins (HCFOs) have a low global warming potential and are attracting attention as environmentally friendly foaming agents, and are therefore advantageously used in the present invention.

The amount of the organic foaming agent (hydrocarbon, hydrofluorocarbon, halogenated olefin) used is preferably 5 to 50 parts by mass, more preferably 10 to 40 parts by mass with respect to 100 parts by mass of the polyol in the composition A. It is preferably a 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 cause a decrease in the strength of the foam and a deterioration in dimensional stability. There is. There is also a problem of disadvantage in terms of cost. On the other hand, if the amount of the organic foaming agent used is less than 5 parts by mass, the function as a foaming agent cannot be fully exerted, the density of the obtained foam may increase, and the composition When added to A and used in an amount too small, the viscosity of the entire composition A becomes high and the mixing property with the composition B deteriorates. For example, in a spray foaming method using a spray gun. , Will cause the problem of not being able to obtain a good spray pattern.

Further, in the present invention, the organic foaming agent (hydrocarbon, hydrofluorocarbon, halogenated olefin) as the foaming agent II is the composition A, the composition B or the foaming agent I (liquefied CO ₂ : critical, subcritical or liquid). When carbon dioxide is added to and used, when an organic foaming agent is added to liquefied CO ₂ and used, the boiling point of the mixture of liquefied CO ₂ and organic foaming agent becomes the boiling point of liquefied CO ₂ (carbon dioxide). Since the temperature is higher than -78.5 ° C), there is an advantage that equipment and facilities for cooling liquefied CO ₂ are not required. As the organic foaming agent added to the liquefied CO ₂ class, a halogenated olefin is preferable from the viewpoint of the influence on the environment, and the blending ratio (mass ratio) with respect to the liquefied CO ₂ class is the liquefied CO ₂ class. Class: Organic foaming agent = 1: 9 to 9: 1, preferably liquefied CO ₂ : Organic foaming agent = 2: 8 to 8: 2.

Further, when the organic foaming agent (hydrocarbon, hydrofluorocarbon, halogenated olefin) and water are used in combination as the foaming agent II in the present invention, the mass ratio of the organic foaming agent and water is 60:40 to 99. It is desirable to use it at a ratio of 9: 0.1, preferably 70:30 to 99: 1, and more preferably 80:20 to 98: 2. If the proportion of water exceeds 40 outside this range, brittleness develops as the reaction progresses, the adhesiveness to the skeleton surface decreases, and problems such as peeling may occur. In addition, carbon dioxide generated by the reaction with isocyanate may lower the thermal conductivity and form a foam layer having an insufficient thermal conductivity. When water is used as the foaming agent II, it is preferable that the water is added to the composition A or the foaming agent I.

As described above, the composition used for producing polyurethane foam according to the production method of the present invention has been described in detail for each component, but in the present invention, in addition to the above-mentioned components, conventionally, when producing polyurethane foam, Any material used as an additive can be used as long as it does not impair the object of the present invention. As such an additive, a defoaming agent can be exemplified. The foam stabilizer is used to uniformly arrange the cell structure of the polyurethane foam, and in the present invention, a silicone-based surfactant or a nonionic surfactant is preferably adopted. Specific examples include polyoxyalkylene-modified dimethylpolysiloxane, polysiloxane-oxyalkylene 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 this defoaming agent is appropriately determined according to the desired foam characteristics, the type of the defoaming agent to be used, and the like, but it is included in 100 parts by mass of the entire 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, using each of the above-mentioned components, a composition A containing a polyol as a main component and a composition B containing a polyisocyanate as a main component are prepared. In the present invention, the viscosity of each composition is prepared. However, each is prepared so as to be 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. If the viscosity of the composition A at 20 ° C. is less than 50 mPa · s, the powdery flame retardant may not show a good dispersed state in the composition, and from the viewpoint of satisfactorily implementing the spray foaming method, The viscosity of the composition A at 20 ° C. is 2000 mPa · s or less. When the powdery flame retardant is added to the composition A and used, the composition A is prepared so that the viscosity of the composition A containing the powdery flame retardant is within the above range.

The composition B is prepared so that the viscosity at 20 ° C. is 50 to 1500 mPa · s, preferably 80 to 1000 mPa · s, and 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 show a good dispersed state in the composition, and from the viewpoint of satisfactorily implementing the spray foaming method, The viscosity of the composition B at 20 ° C. is 1500 mPa · s or less. When the powdery flame retardant is added to the composition B and used, the viscosity of the composition B containing the powdery flame retardant is adjusted to be within the above range.

Then, in the method for producing a polyurethane foam according to the present invention, the above-mentioned composition A, composition B and foaming agent I (liquefied CO ₂ : critical, subcritical or liquid carbon dioxide) are used to make a polyurethane foam. A predetermined amount of the foaming agent I is added to the composition A and / or the composition B at the production site, and after such addition, the target polyurethane foam is produced according to the spray foaming method.

Here, the spray foaming method is one of the conventionally known methods for producing polyurethane foam, and is also referred to as a spray foaming method. Specifically, it is a method of spraying a mixture of the composition A, the composition B and the foaming agent I from the spray gun head of the in-situ foaming machine onto the adherend to foam and cure the polyurethane foam. In the present invention, any method included in the category of the spray foaming method can be adopted without particular limitation. Further, as for various conditions when the spray foaming method is carried out, those according to the characteristics of each composition, the characteristics of the on-site foaming machine and the like are appropriately adopted.

Further, according to the production method of the present invention, low density, uniform density distribution, and good dispersibility of the powdery flame retardant are advantageously realized, and the difference between the total density of the foam and the core density is realized. When heated with a radiant heat intensity of 50 kW / m ² in accordance with the characteristics of 1 to 12 kg / m ³ and the test method specified in ISO-5660, the total calorific value after 20 minutes is 8 MJ. A polyurethane foam having excellent properties such as dimensional stability, which also has a property of / m ² or less, can be advantageously obtained. Further, in the case of performing two-layer spraying (two-stage spraying) particularly in winter when the environmental temperature is low, in the conventional manufacturing method, the density of the first layer foam formed on the surface of the adherend is the first layer. There is a problem that the resulting foam (foam) tends to warp as a whole because the density is higher than that of the second layer foam formed on the top and a difference in shrinkage occurs between the layers. .. However, according to the production method of the present invention, since the density of the foam of the first layer can be suppressed to a low level, the occurrence of warpage can be suppressed in the finally obtained polyurethane foam. ..

Hereinafter, some examples of the present invention will be shown to clarify the features of the present invention more specifically, but the present invention is subject to any restrictions due to the description of such examples. Needless to say, this is not the case. Further, in addition to the following examples, the present invention is further modified in various ways based on the knowledge of those skilled in the art, as long as it does not deviate from the gist of the present invention, in addition to the above-mentioned specific description. It should be understood that modifications, improvements, etc. can be made. In addition, all of% and part 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. Composition A containing a polyol as a main component was prepared and prepared. At the same time, as the composition B containing polyisocyanate as a main component, a composition b1 composed of Wannate PM-130 (product name, Polymeric MDI, manufactured by Manka Kagaku Japan Co., Ltd.) and Wannate PM-200 (product name, Polymeric MDI). , Mange Chemical Japan Co., Ltd.) and Wannate PM-700 (product name, Polymeric MDI, manufactured by Mange Chemical Japan Co., Ltd.) were prepared. The raw materials used in the preparation of the composition A are as follows. Further, the viscosity of each of the prepared compositions A at 20 ° C. was measured, and the results are shown in Tables 1 to 5. On the other hand, when the viscosities of the compositions B (compositions b1 to b3) made of polypeptide MDI were measured at 20 ° C., the viscosities of the composition b1 (Wannate PM-130) were 200 mPa · s, and the viscosities of the composition b2 (Wannate PM-200) were 200 mPa · s. ) Was 330 mPa · s, and the viscosity of the composition b3 (Wannate PM-700) was 750 mPa · s. The viscosity of each composition was measured according to JIS K7117-1: 1999 using the B type of Brookfield type rotational viscometer under the condition of test temperature: 20 ° C. Further, the specific gravity of the composition A was measured using a hydrometer (commercially available product).
-Polyol: Terephthalic acid-based polyester polyol
(Made by Kawasaki Kasei Chemicals Co., Ltd., Product name: RFK505, Relative density: 1.23)
-Polyol: Terephthalic acid-based polyester polyol
(Made by Kawasaki Kasei Chemicals Co., Ltd., Product name: RLK035, Specific density: 1.2)
・ Defoaming agent: Silicone-based defoaming agent
(Manufactured by Toray Dow Corning Co., Ltd., product name: SH-193)
・ Red phosphorus: Nova Excel 140
(Product name, manufactured by Rinkagaku Kogyo Co., Ltd., average particle size: 30 μm, with surface coating treatment, specific gravity: 2.34, red phosphorus content: 92% or more)
-Flame retardant: Phosphate-containing flame retardant
(Ammonium dihydrogen phosphate, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., average particle size: 5 μm, specific gravity: 1.9)
-Flame retardant: Stannate-containing flame retardant
(Zinc tinate, manufactured by Nippon Light Metal Co., Ltd., product name: Framtard S, average particle diameter: 2 μm, specific gravity: 3.9)
-Flame retardant: Boric acid-containing flame retardant
(Zinc borate, manufactured by Mizusawa Industrial Chemicals, Inc., product name: ALCANEX FR-100, average particle size: 4 μm, specific gravity: 2.8)
-Flame retardant: Metal hydroxide
(Aluminum hydroxide, manufactured by Nippon Light Metal Co., Ltd., product name: B1403, average particle size: 2 μm, specific gravity: 2.42)
-Flame retardant: Zinc oxide
(Manufactured by 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)
・ Triquantization catalyst: quaternary ammonium salt
(Made by Kao Corporation, Product Name: Kaorizer No. 420)
-Resination catalyst: N, N-dicyclohexylmethylamine
(Made by Evonik Japan Co., Ltd., Product name: Polycat 12)
-Effervescent agent: HCFO-1233zd
(Honeywell, 1-chloro-3,3,3-trifluoropropene)
-Effervescent agent: HFO-1336mzz
(Chemours, 1,1,1,4,4,4-hexafluoro-2-butene)
・ Foaming agent: HFC245fa
(Manufactured by Central Glass Co., Ltd., 1,1,1,3,3-pentafluoropropan)
・ Foaming agent: HFC365mfc
(Manufactured by SOLVAY Co., Ltd., 1,1,1,3,3-pentafluorobutane)
・ Foaming agent: Liquid CO ₂ + HFO-1234ze (mixture)
(Made by Tokyo High Pressure Yamazaki Co., Ltd., Liquid CO ₂ : HFO-1234ze = 3: 7 (weight ratio))

-Manufacturing of polyurethane foam-
Using the composition A and composition B (polymeric MDI) prepared above, an in-situ foam spraying device (manufactured by Asahi Organic Materials Co., Ltd., product name: AYK-1000 series) equipped with a liquefied carbon dioxide supply device is used. First, liquid carbon dioxide in the proportions shown in Tables 1 to 5 or a mixture of liquid carbon dioxide and HFO-1234ze is supplied to composition A and mixed, and then the obtained liquid carbon dioxide is obtained. Composition A containing (liquid CO ₂ ) and the like was contact-mixed with composition B at a volume ratio of 1: 1. Continuously from such contact mixing, the surface of the flexible board (910 mm × 910 mm), which is the skeleton, is sprayed once with one bottom blow and two times with top blow, and reacted on the board to foam and cure. A foamed layer made of various rigid polyurethane foams according to Examples 1 to 22 and Comparative Examples 1 to 7, wherein the bottom blowing layer is 5 mm or less and the two top blowing layers are 30 mm or less, respectively (total thickness: about). 60 mm) were formed respectively.

Then, using each polyurethane foam thus obtained as a sample, the overall density and the core density are measured (calculated), and the dimensional stability (shrinkage), the dimensional stability (warp), and the flame retardancy (JIS) are evaluated. did. The measurement or evaluation was performed according to the procedure shown below. The obtained results are shown in Tables 1 to 5 below. In addition, "not sprayable" in Comparative Example 8 of Table 5 means that although the production of polyurethane foam was attempted by spraying according to the above procedure, sufficient polyurethane foam was not formed.

-Measurement (calculation) of overall density and core density-
The thickness of the polyurethane foam having the skin layer (surface layer) formed by spraying on the flexible board was measured at 13 points located at approximately equal distances in the vertical and horizontal directions, and the average thickness at the 13 points was used to measure the polyurethane. While obtaining the volume of the foam, the mass of the flexible board sprayed with the polyurethane foam is further measured, and the total density is calculated by obtaining the mass of the polyurethane foam by subtracting the mass of the flexible board measured in advance. .. Further, the skin layer (surface layer) is removed from the foam layer formed on the flexible board to reveal the core layer, a polyurethane foam of 100 mm × 100 mm × 25 mm is cut out, and the mass thereof is determined to obtain the core density. Is calculated. The "difference between the total density and the core density" shown in Tables 1 to 5 below is the value obtained by subtracting the value of the core density from the value of the total density.

-Evaluation of dimensional stability (shrinkage)-
From each of the obtained polyurethane foams, a test piece having a size of 100 mm × 100 mm × 25 mm including an internal skin layer (skin layer formed by the first top blowing) is cut out. The cut out test piece is allowed to stand in an environment of -30 ° C for 48 hours, then the size of the test piece is measured with a caliper, and the measurement result is used to obtain the dimensional change rate (shrinkage) from the following formula (1). ) Is calculated.
Dimensional change rate (%)
= ([Dimensions of test piece after test]-[Dimensions of test piece before test])
/ [Dimensions of test piece before test] x 100
The calculated dimensional change rate (shrinkage) is evaluated according to the following criteria. The evaluations of ◎ and ○ are acceptable.
⊚: The dimensional change rate is less than 1%.
◯: The dimensional change rate is 1% or more and less than 3%.
Δ: The dimensional change rate is 3% or more and less than 7%.
X: The dimensional change rate is 7% or more.

-Evaluation of dimensional stability (warp)-
From each of the obtained polyurethane foams, a test piece having a size of 100 mm × 100 mm × 25 mm including an internal skin layer (skin layer formed by the first top blowing) is cut out. The cut out test piece was allowed to stand in an environment of -30 ° C for 48 hours, and then the test piece was placed on a horizontal table, and the presence or absence of warpage in the test piece was visually confirmed and then rattled. Check for stickiness and evaluate according to the following criteria.
○: No warping or rattling is observed.
X: Either warpage or rattling is observed.

-Evaluation of foam workability-
Using the polyurethane foam having a skin layer (surface layer) formed by spraying on the flexible board used in the above-mentioned measurement of the total density and the core density, the end portion of the polyurethane foam protruding from the flexible board was used. Cut along the peripheral edge of the flexible board with a cutter knife, and evaluate the processability of the polyurethane foam according to the following criteria based on the tactile sensation at that time.
⊚: Almost no force is required for cutting, and the cut surface is also good.
◯: Some force is required for cutting, but the cut surface is good.
Δ: A large force is required for cutting, and there are some difficulties in the cut surface.
X: It is difficult to cut with a utility knife, it can be cut with a saw, and there is a problem with the cut surface.

-Evaluation of flame retardancy (JIS)-
In accordance with the combustibility measurement method specified in JIS A9526: 2015, a 50 mm × 150 mm × 13 mm test piece was cut out from each obtained polyurethane foam, and one end of this test piece was a burner equipped with a fish taillight. Burn for 60 seconds with a burner, and measure the time to extinguish the flame and the burning distance, respectively. The measurement results will be evaluated according to the following criteria. The evaluations of ⊚ and ◯ are accepted, and the evaluation results are shown in the “flame retardant (JIS)” column in Tables 1 to 5.
⊚: The burning distance is less than 30 mm and the burning time is less than 60 seconds.
◯: The burning distance is less than 60 mm and the burning time is less than 120 seconds.
Δ: The burning distance is 60 mm or more, or the 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 4, in each of the polyurethane foams (Examples 1 to 22) produced according to the production method of the present invention, the overall density and the core density are the same. Since the difference is small, it is recognized that the polyurethane foam has a uniform density distribution with little density bias due to the addition of the powdery flame retardant, and all of these polyurethane foams have dimensional stability and foam processing. It is also recognized that it is excellent in sex and flame retardancy.

On the other hand, as is clear from the results shown in Tables 4 and 5, in the polyurethane foam according to Comparative Example 1 in which only water was used as the foaming agent and no liquid CO ₂ was added, the overall density and the core were used. Since the difference from the density is large, it is confirmed that there are many variations in the density due to the addition of the powdery flame retardant, and there are problems in dimensional stability and foam processability. In addition, any of the polyurethane foams to which no flame retardant is added (Comparative Example 2) and the polyurethane foams to which a flame retardant in an amount exceeding the range of the present invention is added (Comparative Examples 3 to 7) However, it is recognized that it does not have sufficient flame retardancy.

In addition, each polyurethane foam according to Examples 1 and 8 to 16 and each polyurethane foam according to Comparative Examples 1 to 3 were further evaluated for flame retardancy according to the procedure shown below.

-Evaluation of flame retardancy (ISO)-
From each of the obtained polyurethane foams, a sample for a cone calorimeter test having a size of 100 mm × 100 mm × 50 mm was cut out and subjected to a radiant heat intensity of 50 kW / m ² in accordance with the combustion test method specified in ISO-5660. The maximum calorific value and total calorific value when heated for 10 minutes and the total calorific value when heated for 20 minutes (maximum calorific value is the same as that for 10 minutes) are measured. The flame retardancy of these measurement results is evaluated according to the following criteria. In the following, the total calorific value when heated for 10 minutes is shown as the total calorific value (10 minutes), and the total calorific value when heated for 20 minutes is shown as the total calorific value (20 minutes), and the evaluation results are shown. It is shown in the "flame retardant (ISO)" column in 6.
⊚: The maximum heat generation rate is 80 kW / m ² or less, and both the total heat generation amount (10 minutes) and the total heat generation amount (20 minutes) are 7 MJ / m ² or less.
◯: The maximum heat generation rate is 80 kW / m ² or less, and both the total heat generation amount (10 minutes) and the total heat generation amount (20 minutes) are 8 MJ / m ² or less.
Δ: The maximum heat generation rate is 80 kW / m ² or less, the total heat generation amount (10 minutes) is 8 MJ / m ² or less, and the total heat generation amount (20 minutes) exceeds 8 MJ / m ² .
X: The maximum heat generation rate exceeds 80 kW / m ² , or both the total heat generation amount (10 minutes) and the total heat generation amount (20 minutes) exceed 8 MJ / m ² .

As is clear from the results shown in Table 6, the polyurethane foams (Example 1, Examples 8 to 16) produced according to the production method of the present invention have a combustion test method based on ISO-5660. It is recognized that a polyurethane foam having a high degree of flame retardancy having a total calorific value (20 minutes) of 8 MJ / m ² or less can be obtained.

Claims (10)

When producing a polyurethane foam by mixing a composition A containing a polyol as a main component and a composition B containing a polyisocyanate as a main component and reacting them to foam and cure them.
The composition A and / or the composition of the powdery flame retardant having a specific gravity of 1.0 to 5.0 at a ratio of 1 to 70 parts by mass with respect to 100 parts by mass of the polyol in the composition A. It is contained in the thing B,
Using the composition A prepared to have a viscosity at 20 ° C. of 50 to 2000 mPa · s and the composition B prepared to have a viscosity at 20 ° C. of 50 to 1500 mPa · s,
At the production site of the polyurethane foam, a foaming agent I composed of critical, subcritical or liquid carbon dioxide is added to the composition A and / or the composition B, and after such addition, the polyurethane is added according to a spray foaming method. Foam is manufactured,
A method for manufacturing polyurethane foam. The method for producing a polyurethane foam according to claim 1, wherein the powdery flame retardant has an average particle size of 50 μm or less. The powdery flame retardant is contained in the composition A, and the specific gravity of the powdery flame retardant is 1 times or more and 5 times or less the specific gravity of the composition A. The method for manufacturing a polyurethane foam according to. Claim that the powdery flame retardant is at least one selected from red phosphorus, phosphate-containing flame retardant, stannate-containing flame retardant, boron-containing flame retardant, metal hydroxide and metal oxide. The method for producing a polyurethane foam according to any one of claims 1 to 3. The method for producing a polyurethane foam according to any one of claims 1 to 4, wherein a liquid flame retardant is further contained in the composition A and / or the composition B. The method for producing a polyurethane foam according to claim 5, wherein the liquid flame retardant is at least one selected from a phosphoric acid ester and a bromine-containing flame retardant. The method for producing a polyurethane foam according to any one of claims 1 to 6, wherein the powdery flame retardant contains red phosphorus as an essential component and contains at least one flame retardant other than red phosphorus. .. The foaming agent II composed of at least one of water, hydrocarbon, hydrofluorocarbon and halogenated olefin is added to at least one of the composition A, the composition B and the foaming agent I. The method for producing a polyurethane foam according to any one of claims 1 to 7, which is further contained. The method for producing a polyurethane foam according to any one of claims 1 to 8, wherein a polyurethane foam having a difference between the total density and the core density of 0.1 to 12 kg / m ³ can be obtained. Claims that a polyurethane foam having a total calorific value of 8 MJ / m ² or less after 20 minutes can be obtained when heated at a radiant heat intensity of 50 kW / m ² in accordance with the test method specified in ISO-5660. The method for producing a polyurethane foam according to any one of items 1 to 9.