JP2020128458A - Method for producing polyurethane foam - Google Patents

Abstract

To provide a production method which can make polyurethane foam having excellent flame retardancy and uniform density distribution advantageous.SOLUTION: In a production site of polyurethane foam using a composition A having a viscosity at 20°C of 50 to 2000 mPa s and a composition B having a viscosity at 20°C of 50 to 1500 mPa s prepared by incorporating a predetermined amount of a powdery flame-retardant into a composition A and/or a composition B in producing 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, followed by foaming and curing, a foaming agent I consisting of critical, sub-critical or liquid carbon dioxide is added to the composition A and/or the composition B, after such an addition, polyurethane foam is produced according to a spray foaming method.SELECTED DRAWING: 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, according to the spray foaming method (spray foaming method), when spraying a target adherend (structure) from the spray gun head of the on-site foaming machine, and foaming and curing it, it is possible to produce a polyurethane foam by using powdery materials. The use of the flame retardant may cause the following problems. That is, 1) the powdery flame retardant may inhibit the progress of the urethane reaction, and 2) the specific gravity of the powdery flame retardant is generally higher than the specific gravity of the entire composition, Due to the low dispersibility of the powdery flame retardant, in the finally obtained polyurethane foam, the flame retardant is present in a biased state, and as a result, the polyurethane foam having a biased density distribution. There is an inherent problem of being manufactured.

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 by mixing a composition A containing a polyol as a main component with a composition B containing a polyisocyanate as a main component and reacting them to foam and cure,
The powdery flame retardant is contained in the composition A and/or the composition B in a ratio of 1 to 70 parts by mass with respect to 100 parts by mass of the polyol in the composition A,
Using the composition A having a viscosity at 20° C. of 50 to 2000 mPa·s and the composition B having a viscosity at 20° C. of 50 to 1500 mPa·s,
At the production site of the polyurethane foam, a blowing agent I made of carbon dioxide in a critical, subcritical or liquid state is added to the composition A and/or the composition B, and after the addition, a blowing foaming method is applied. The polyurethane foam is manufactured,
A method for producing a polyurethane foam, comprising:
(2) The method for producing a polyurethane foam according to the aspect (1), wherein the powdery flame retardant has an average particle diameter of 50 μm or less.
(3) The aspect (1) or 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 2).
(4) The aspect in which the powdery flame retardant is contained in the composition A, and the specific gravity of the powdery flame retardant is 1 time or more and 5 times or less the specific gravity of the composition A. (1) thru|or the manufacturing method of the polyurethane foam as described in any one of said aspect (3).
(5) The powdery flame retardant is at least one selected from red phosphorus, phosphate-containing flame retardants, stannate-containing flame retardants, boron-containing flame retardants, metal hydroxides and metal oxides. The method for producing a polyurethane foam according to any one of the above aspects (1) to (4).
(6) The polyurethane foam according to any one of the aspects (1) to (5), wherein a liquid flame retardant is further contained in the composition A and/or the composition B. Production method.
(7) The polyurethane according to any one of aspects (1) to (6), wherein the liquid flame retardant is at least one selected from phosphoric acid esters and bromine-containing flame retardants. Form manufacturing method.
(8) Any one of the above aspects (1) to (7), wherein the powdery flame retardant contains red phosphorus as an essential component and at least one flame retardant other than red phosphorus. The method for producing a polyurethane foam according to.
(9) The foaming agent II made 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 aspects (1) to (8), which is further included.
(10) Polyurethane according to any one of the aspects (1) to (9), wherein a polyurethane foam having a difference between the overall density and the core density of 0.1 to 12 kg/m ³ is obtained. Form manufacturing method.
(11) Polyurethane 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 according to the test method specified in ISO-5660. The method for producing a polyurethane foam according to any one of the aspects (1) to (10), in which the above is obtained.

According to such a method for producing a polyurethane foam according to the present invention, it is possible to advantageously enjoy the effects listed below.
(1) A mixture of the composition A and the composition B by the 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 favorably maintained. In other words, the powdery flame retardant is uniformly present in the mixture (reactant) without uneven distribution. Therefore, the obtained polyurethane foam exhibits excellent flame retardancy due to the flame retardant and also has a uniform density distribution.
(2) Polyurethane foam obtained in accordance with the present invention in which the powdery flame retardant is well dispersed and has a uniform density distribution has moderately low elasticity and surface hardness, and the entire foam has flexibility. Because of its performance, it excels in workability such as cutting and cutting, and it is easy to perform cutting work and the like performed after the foam is manufactured by the blowing and foaming method.
(3) When the present invention is applied to perform two-layer spraying (two-stage spraying) in a low environment temperature such as winter, the first-layer foam (foam formed by the first spray) and the second-layer foam The final difference is that the density difference between the eye foam (foam formed by the second spraying) is small and therefore the occurrence of the difference in shrinkability between the layers is effectively suppressed. The polyurethane foam obtained in 1 above has suppressed warpage as a whole. Further, according to the production method of the present invention, even if a polyurethane foam is produced by a blowing foaming method in a low temperature environment, the above-mentioned polyurethane 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 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, either of the above-described composition A containing a polyol as a main component or composition B containing a polyisocyanate as a main component, or both of the composition A and the composition B, A powdered flame retardant is added. In the present invention, the amount of powdery flame retardant used (when added to both composition A and composition B, the total amount added to each composition) is the amount of the polyol in 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 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 composition in which it was added In addition to increasing the viscosity of the product and causing problems such as poor stirring, there is a risk of causing problems such as reduced workability and the fact that the polyurethane foam rather burns easily.

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, and further preferably 1 to 35 μm. is there. A powdery flame retardant having an average particle diameter of 50 μm or less is used, and the composition A containing a polyol as a main component and the composition B containing a polyisocyanate as a main component are adjusted so that the viscosities fall within predetermined ranges. By using the prepared one, the sedimentation rate of the powdery flame retardant in the composition (and in the mixture of the two kinds of compositions) becomes slower more effectively, and the powdery flame retardant has a good dispersion state. Since it is maintained for a longer time, the effect of the present invention can be more advantageously 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, when the powdery flame retardant is used by being contained in the composition A containing a polyol as a main component, the specific gravity of the powdery flame retardant is 1 to 5 times the specific gravity of the composition A. It is preferably 1 times or more and 4.5 times or less, 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 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, but in the present invention, the coated red phosphorus is advantageously used among the known red phosphorus from the viewpoint of safety and easy handling. 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.

-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.

In addition, in the production method of the present invention, it is possible to use a liquid flame retardant 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.

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

Here, as is well known, critical, subcritical, or liquid carbon dioxide (hereinafter, abbreviated as liquefied CO ₂ ) means that supercritical carbon dioxide is obtained by pressurizing carbon dioxide gas at a predetermined temperature. It is in 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 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. .. In addition, the use of liquefied CO ₂ improves the sprayability of the mixture of the composition A and the composition B in the spray foaming method (spray foaming method) described later, and in addition, the powdery difficult The occurrence of clogging in the spray gun due to the fuel is advantageously suppressed. In the present invention, if the amount of liquefied CO ₂ used is too small, the effect of its addition cannot be sufficiently expressed, and the foaming immediately after spraying by the spray foaming method (spray foaming method) becomes insufficient, Since the difference in density 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 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 causes a problem in 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, 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.

In the present invention, it is preferable to use a foaming agent II composed of at least one of water, hydrocarbons, hydrofluorocarbons and halogenated olefins together with the above-mentioned liquefied CO ₂ class (foaming agent I). 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 so as to be within the range defined above.

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 the polyisocyanate, and this carbon dioxide also contributes to the foaming of the polyurethane. Therefore, in the present invention, carbon dioxide generated by the reaction between the water and the polyisocyanate is The amount of the organic foaming agent described below is more than 1 mol and not more than 20 mol with respect to 1 mol of the total amount of carbon dioxide used as the liquefied CO ₂ described above. It is made to exist in the mixture of the substance A and the composition B.

In the present invention, as the blowing agent II, instead of or together with the above-mentioned water, an organic blowing agent such as hydrocarbon (HC), hydrofluorocarbon (HFC), hydrofluoroolefin (HFO) or hydrochlorofluoroolefin ( A halogenated olefin (halogenated alkene) called HCFO) is used. 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.

In the present invention, the blowing agent II serving organic blowing agent (hydrocarbon, hydrofluorocarbon, halogenated olefin), the composition A, composition B or the foaming agent I (liquefied CO ₂ type: critical, subcritical or liquid When used by adding an organic blowing agent to the liquefied CO ₂ when used, the boiling point of the mixture of the liquefied CO ₂ and the organic blowing agent is the boiling point of the liquefied CO ₂ ( Since the temperature is higher than −78.5° C.), there is an advantage that a device or equipment for cooling the liquefied CO ₂ is 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, as the foaming agent II in the present invention, when an organic foaming agent (hydrocarbon, hydrofluorocarbon, halogenated olefin) and water are used in combination, the organic foaming agent and water have a mass ratio of 60:40 to 99. It is desirable to use it in a ratio of 9:0.1, preferably 70:30 to 99:1, and 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 II, water is preferably added to the composition A or the foaming agent I.

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.

And the composition A which has a polyol as a main component and the composition B which has a polyisocyanate as a main component will be prepared using the above-mentioned each component, but in the present invention, the viscosity of each composition Are each adjusted to fall 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. When a powdery flame retardant is used by being added to the composition A, the composition A is prepared so that the viscosity of the composition A containing the powdery flame retardant is within the above range.

Further, 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. When 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 performing the blowing foaming method well, 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 composition B is prepared so that the viscosity of the composition B containing the powdery flame retardant is within the above range.

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

Here, the blowing foaming method is one of conventionally known polyurethane foam manufacturing methods, and is also called a spray foaming method. Specifically, it is a method of producing a polyurethane foam by spraying a mixture of the composition A, the composition B, and the foaming agent I from the spray gun head of an in-situ foaming machine onto an adherend to cause foaming and curing. In the present invention, any method can be adopted without particular limitation as long as it is a method included in the category of the blowing and foaming method. Various conditions for carrying out the blowing and foaming method may be appropriately adopted depending on the characteristics of each composition, the characteristics of the on-site foaming machine, and the like.

Then, according to the production method of the present invention, a low density, a uniform density distribution, and good dispersibility of the powdery flame retardant are advantageously realized, and the difference between the overall density of the foam and the core density is achieved. Is 1 to 12 kg/m ^3, and when heated at a radiant heat intensity of 50 kW/m ² in accordance with 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 and having a property of not more than /m ² is advantageously obtained. Further, when 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 foam of the first layer formed on the surface of the adherend is The density of the second layer foam formed on top of the foam is higher than the density of the second layer foam, and there is a difference in shrinkability between the layers, so that the resulting foam (foam) tends to warp as a whole. .. 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 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 A containing a polyol as a main component were prepared and prepared. In addition, as the composition B containing polyisocyanate as a main component, a composition b1 made of Wannate PM-130 (product name, Polymeric MDI, manufactured by Wanka Kagaku Japan Co., Ltd.), Wannate PM-200 (product name, polymeric MDI). A composition b2 made of Wanka Chemical Japan Co., Ltd. and a composition b3 made of Wannate PM-700 (product name, Polymeric MDI, manufactured by Wanka Chemical Japan Co., Ltd.) were prepared. 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. On the other hand, when the viscosity of the composition B composed of the polymeric MDI (compositions b1 to b3) was measured at 20° C., the viscosity of the composition b1 (Wannate PM-130) was 200 mPa·s, and the composition b2 (Wannate PM-200). ), 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 a Brookfield type rotational viscometer type B under a test temperature of 20°C. Moreover, the specific gravity of the composition A was measured using a specific gravity meter (commercially available product).
・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)
・Red phosphorus: Nova Excel 140
(Product name, manufactured by Rin Kagaku Kogyo Co., Ltd., average particle diameter: 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 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: 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))

-Manufacture of polyurethane foam-
Using the above-prepared composition A and composition B (polymeric MDI), with an in-situ foaming spraying device (Asahi Organic Materials Co., Ltd., product name: AYK-1000 series) equipped with a liquefied carbon dioxide supply device, First, the composition A was supplied with liquid carbon dioxide in the proportions shown in Tables 1 to 5, or a mixture of liquid carbon dioxide and HFO-1234ze, and after mixing, the obtained liquid carbon dioxide was obtained. The composition A containing (liquid CO ₂ ) or the like was contact mixed with the 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 body, is sprayed once downward and twice upward, and reacted on such board to foam and cure. , The bottom blown layer is 5 mm or less, and the two upper blown layers are each 30 mm or less, foamed layer made of various rigid polyurethane foam according to Examples 1-22 and Comparative Examples 1-7 (total thickness: about 60 mm) respectively.

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

-Measurement (calculation) of overall density and core density-
The thickness of the polyurethane foam having a skin layer (surface layer) formed by spraying on the flexible board was measured at 13 points vertically and horizontally equidistantly, and the average of the thicknesses at the 13 points was used to determine the polyurethane. While determining the foam volume, weigh the flexible board sprayed with polyurethane foam, and subtract the previously measured flexible board weight to obtain the polyurethane foam mass, thereby calculating the overall density. .. Further, the skin layer (surface layer) is removed from the foam layer formed on the flexible board to expose the core layer, and a 100 mm×100 mm×25 mm polyurethane foam is cut out, and its mass is determined to determine the core density. To calculate. The “difference between the overall density and the core density” shown in Tables 1 to 5 below is obtained by subtracting the numerical value of the core density from the numerical value of the overall 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 (a skin layer formed by the first upper 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 calculate the dimensional change rate (shrinkage) according to the following formula (1). ) Is calculated.
Dimensional change rate (%)
= ([Dimension of test piece after test]-[Dimension of test piece before test])
/[Dimension of test piece before test]×100
The calculated dimensional change rate (shrinkage) is evaluated according to the following criteria. In addition, the evaluation of ◎ and ○ is passed.
A: 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 (warpage)-
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 (a skin layer formed by the first upper blowing) is cut out. The cut-out test piece was allowed to stand for 48 hours in an environment of −30° C., 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 checked. Check the presence or absence of sticking and evaluate according to the following criteria.
◯: No warp or rattling is observed.
X: Either warpage or rattling is recognized.

-Evaluation of foam processability-
Using the polyurethane foam having a skin layer (surface layer) formed by spraying on the flexible board, which was used in the measurement of the overall density and the core density, the end of the polyurethane foam protruding from the flexible board was used. The flexible board is cut with a cutter knife along the peripheral edge of the flexible board, and the touchability at that time is used to evaluate the processability of the polyurethane foam according to the following criteria.
⊚: 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 flame retardance (JIS)-
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 measurement results are evaluated according to the following criteria. The evaluations of ⊚ and ◯ are passed, and each evaluation result is shown in the “flame retardancy (JIS)” column in Tables 1 to 5.
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 4, in the polyurethane foams manufactured according to the manufacturing method of the present invention (Examples 1 to 22), the total density and the core density were Since the difference is small, it is confirmed that the polyurethane foam has a uniform density distribution with less uneven density due to the addition of powdered flame retardant. Also, all of these polyurethane foams have dimensional stability and foam processing. It is recognized that it is also excellent in heat resistance 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 liquid CO ₂ was not added, the overall density and the core 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, in any of the polyurethane foam to which the flame retardant is not added (Comparative Example 2) and the polyurethane foam to which the flame retardant in an amount exceeding the range of the present invention is added (Comparative Examples 3 to 7), However, it is recognized that they do not have sufficient flame retardancy.

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

-Evaluation of flame retardance (ISO)-
From each of the obtained polyurethane foam, a 100 mm × 100 mm × 50 mm size cone calorimeter test sample was cut out, in accordance with the combustion test method specified in ISO-5660, at a radiant heat intensity of 50 kW/m ² , The maximum heat generation rate and total heat generation amount after heating for 10 minutes, and the total heat generation amount after heating for 20 minutes (the maximum heat generation amount is the same value as that during 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 after heating for 10 minutes is shown as the total calorific value (10 minutes), and the total calorific value after heating for 20 minutes is shown as the total calorific value (20 minutes). It is shown in the column of "flame retardancy (ISO)" in No. 6.
A: 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, in the polyurethane foams manufactured according to the manufacturing method of the present invention (Example 1, Example 8 to Example 16), the combustion test method according to ISO-5660 was used. In the above, it is recognized that a polyurethane foam having a high degree of flame retardancy with a total calorific value (20 minutes) of 8 MJ/m ² or less is obtained.

Claims (11)

When a polyurethane foam is produced 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,
The powdered flame retardant is contained in the composition A and/or the composition B at a ratio of 1 to 70 parts by mass with respect to 100 parts by mass of the polyol in the composition A,
Using the composition A having a viscosity at 20° C. of 50 to 2000 mPa·s and the composition B having a viscosity at 20° C. of 50 to 1500 mPa·s,
At the production site of the polyurethane foam, a blowing agent I consisting of critical, subcritical or liquid carbon dioxide is added to the composition A and/or the composition B, and after the addition, the polyurethane is produced according to a blowing foaming method. The foam is manufactured,
A method for producing a polyurethane foam, comprising: 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 method for producing a polyurethane foam according to claim 1 or 2, wherein the powdery flame retardant has a specific gravity of 1.0 to 5.0. The powdery flame retardant is contained in the composition A, and the specific gravity of the powdery flame retardant is 1 to 5 times the specific gravity of the composition A. 4. The method for producing a polyurethane foam according to any one of 3 above. The powdery flame retardant is at least one selected from red phosphorus, phosphate-containing flame retardants, stannate-containing flame retardants, boron-containing flame retardants, metal hydroxides and metal oxides. The method for producing the polyurethane foam according to any one of claims 1 to 4. The method for producing a polyurethane foam according to any one of claims 1 to 5, 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 any one of claims 1 to 6, 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 7, wherein the powdery flame retardant contains red phosphorus as an essential component and at least one flame retardant other than red phosphorus. .. A foaming agent II composed of at least one or more 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 8, further comprising: The method for producing a polyurethane foam according to claim 1, wherein a polyurethane foam having a difference between the overall density and the core density of 0.1 to 12 kg/m ³ is obtained. A polyurethane foam having a total calorific value of 8 MJ/m ² or less after 20 minutes is obtained when heated at a radiant heat intensity of 50 kW/m ² according to the test method specified in ISO-5660. Item 11. A method for producing a polyurethane foam according to any one of items 1 to 10.