TWI857195B - Polyol composition, flame retardant rigid polyurethane foam and method for producing the same - Google Patents

Abstract

A polyol composition is provided, which can suppress the aggregation of powder in a raw material liquid of a polyol composition containing a flame retardant containing a specified phosphinic acid metal salt and/or a phosphoric acid metal salt and a flame retardant rigid polyurethane foam, and can obtain a flame retardant rigid polyurethane foam with excellent flame retardancy; and a flame retardant rigid polyurethane foam using the polyol composition and a method for producing the same. The polyol composition of the present invention contains: a polyol compound containing an aromatic polyester polyol; a flame retardant containing one or more compounds selected from the group containing a specified phosphinic acid metal salt and a phosphoric acid metal salt; and a dispersant containing Neuburg Siliceous Earth particles.

Description

Polyol composition, flame retardant rigid polyurethane foam and method for producing the same

The present invention relates to a polyol composition for producing a flame retardant rigid polyurethane foam, a flame retardant rigid polyurethane foam using the polyol composition, and a method for producing the same.

Rigid polyurethane foam has excellent thermal insulation performance, and is also excellent in processability and economy. From the perspective of energy conservation and improvement of living quality, it is widely used as a thermal insulation material for buildings.

On the other hand, rigid polyurethane foam is an organic polymer material and has the characteristic of being flammable. Fire accidents caused by rigid polyurethane foam often occur due to sparks from welding and hot cutting operations during construction, renovation, and demolition projects. Various ideas for making rigid polyurethane foam flame-retardant are being reviewed as a measure to reduce such fire accidents.

For example, it is known that red phosphorus and phosphate esters are added as flame retardants to rigid polyurethane foam to make it flame retardant. However, red phosphorus is a flammable substance, and sufficient attention must be paid to ensure safety during handling. In addition, red phosphorus and phosphate esters have a limited degree of improvement in the flame retardancy of rigid polyurethane foam, and a flame retardant that can impart better flame retardancy and make rigid polyurethane foam close to non-flammable materials is desired.

Regarding this topic, the inventors of the present invention have examined the application of a flame retardant containing a phosphinic acid-based metal salt, which is used as a flame retardant for polyurethane resin for synthetic leather in Patent Document 1, as a more effective flame retardant. [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2016-79375

[Problems to be solved by the invention]

However, the flame retardant containing a phosphinate metal salt described in the above-mentioned Patent Document 1 is also difficult to dissolve in polyol compounds or polyisocyanate compounds which are raw materials for rigid polyurethane foams, similar to conventional flame retardants such as red phosphorus, and is a powdery flame retardant with a high specific gravity and is easily agglomerated in the raw material liquid of rigid polyurethane foams.

In the production of flame retardant rigid polyurethane foam, adding flame retardant at the production site will increase the burden of on-site operations, so generally a polyol composition (polyol premix) or a raw material liquid of rigid polyurethane foam to which flame retardant has been added is used. As mentioned above, the polyol composition or raw material liquid of rigid polyurethane foam prepared by pre-dispersing the powdered flame retardant may also condense when used, and it will require a lot of work to redisperse it, and it will also become difficult to redisperse it evenly.

Therefore, when using the powdered flame retardant containing the phosphinate metal salt, it is desired to suppress the aggregation of the powder (solid) in the raw material liquid of the polyol composition or the rigid polyurethane foam and to have excellent handling properties in obtaining a uniform raw material composition. The same is true for the powdered flame retardant containing the phosphate metal salt.

The present invention is made to solve the above-mentioned technical problems, and aims to provide a polyol composition and a flame retardant rigid polyurethane foam using the same and a method for producing the same. The polyol composition can suppress the aggregation of powder in a raw material liquid of a polyol composition and a flame retardant containing a specified phosphite metal salt and/or phosphoric acid metal salt and a flame retardant rigid polyurethane foam, and can obtain a rigid polyurethane foam with excellent flame retardancy. [Means for solving the problem]

The present invention is based on the following discovery: In a polyol composition containing a flame retardant including a specified phosphite-based metal salt, by using a specified dispersant, the aggregation of the powdered flame retardant can be effectively suppressed, and a rigid polyurethane foam having excellent flame retardancy can be obtained. In addition, it was discovered that in a polyol composition containing a flame retardant including a phosphate-based metal salt, by using a dispersant containing Neuburg Siliceous Earth particles, the aggregation of the powdered flame retardant can also be effectively suppressed, and a rigid polyurethane foam having excellent flame retardancy can be obtained.

That is, the present invention provides the following [1] to [9]. [1] A polyol composition for producing a flame-retardant rigid polyurethane foam, comprising: a polyol compound comprising an aromatic polyester polyol; a flame retardant comprising one or more compounds selected from the group consisting of a phosphite metal salt and a phosphate metal salt represented by the following formula (1); and a dispersant comprising Neuburg silica particles.

(In formula (1), M is Mg, Al, Ca, Ti or Zn, ^R1 is a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms or a phenyl group, and n is 2, 3 or 4.) [2] The polyol composition described in [1] above, wherein the polyol compound comprises a Mannich polyol. [3] The polyol composition described in [1] or [2] above, wherein the Neuburg silica particles are contained in an amount of 1 to 50 parts by weight relative to 100 parts by weight of the total solid content of the flame retardant. [4] The polyol composition described in any one of [1] to [3] above, which comprises a blowing agent. [5] The polyol composition described in [4] above, wherein the blowing agent comprises one or more of a hydrofluoroolefin and a hydrochlorofluoroolefin. [6] The polyol composition as described in any one of [1] to [5] above, which contains a catalyst. [7] The polyol composition as described in any one of [1] to [6] above, which contains a foam stabilizer.

[8] A flame retardant rigid polyurethane foam, which is a reaction product of a polyol composition as described in any one of [1] to [7] and a polyisocyanate compound. [9] A method for producing a flame retardant rigid polyurethane foam, which comprises mixing a polyol composition as described in any one of [1] to [7] and a polyisocyanate compound, foaming and curing the mixture to obtain a flame retardant rigid polyurethane foam. [Effect of the Invention]

According to the present invention, a polyol composition can be provided, which can suppress the aggregation of powder in the liquid in a polyol composition containing a flame retardant of a specified phosphite metal salt and a raw material liquid of a flame retardant rigid polyurethane foam, and has excellent handling properties. In addition, by using the aforementioned polyol composition, a rigid polyurethane foam with excellent flame retardancy can be obtained. In addition, according to the present invention, in a polyol composition containing a flame retardant containing a phosphate metal salt, the aggregation of the powdered flame retardant can also be effectively suppressed, and a rigid polyurethane foam with excellent flame retardancy can be obtained.

[Form used to implement the invention]

Hereinafter, the polyol composition of the present invention, the flame retardant rigid polyurethane foam using the same, and the method for producing the same are described in detail.

[Polyol composition] The polyol composition of the present invention is a polyol composition for producing flame-retardant rigid polyurethane foam, which contains: a polyol compound comprising an aromatic polyester polyol; a flame retardant comprising one or more compounds selected from the group consisting of a phosphite metal salt and a phosphate metal salt represented by the following formula (1); and a dispersant comprising Neuburg silica particles.

In the above formula (1), M is Mg, Al, Ca, Ti or Zn, ^R1 is a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms or a phenyl group, and n is 2, 3 or 4.

By blending the aforementioned dispersant, the aggregation of powder in the raw material liquid of the flame retardant rigid polyurethane foam containing the flame retardant comprising the phosphite metal salt and/or the phosphoric acid metal salt represented by the aforementioned formula (1) can be effectively suppressed. Accordingly, when manufacturing the flame retardant rigid polyurethane foam, the work load for uniformly mixing the polyol composition and the raw material liquid of the flame retardant rigid polyurethane foam can be reduced, and the uniform dispersion of the powder in the aforementioned raw material liquid can be improved. In addition, the excellent flame retardancy caused by the aforementioned flame retardant in the obtained flame retardant rigid polyurethane foam can be maintained.

<Polyol compound> The polyol compound is a raw material compound of the flame-retardant rigid polyurethane foam, and constitutes the polyol composition of the present invention. The aforementioned polyol compound is an alcohol compound having two or more hydroxyl groups, and generates a polyurethane resin by an addition polymerization reaction with a polyisocyanate compound.

From the perspective of good flame retardancy, aromatic polyols are mainly used as polyol compounds for the production of flame retardant rigid polyurethane foams. Aromatic polyols can impart better flame retardancy than polypropylene glycol, which is generally used as a raw material for polyurethane foams.

From the viewpoint of obtaining a flame retardant rigid polyurethane foam having good flame retardancy and hardness, the hydroxyl group value of the aromatic polyol is preferably 100 to 900 mgKOH/g, more preferably 150 to 800 mgKOH/g, and further preferably 180 to 700 mgKOH/g.

The polyol compound in the present invention includes an aromatic polyester polyol, and preferably includes a Mannich polyol. Although the aggregation of powder in the raw material liquid of the flame retardant rigid polyurethane foam can be well suppressed by the aforementioned dispersant, the aggregation of powder can be more effectively suppressed by including the dispersant and the Mannich polyol as the aforementioned polyol compound.

From the viewpoint of obtaining a flame retardant rigid polyurethane foam having good flame retardancy and hardness, the total content of the polyol compounds in 100 parts by mass of the polyol composition is preferably 10.0 to 60.0 parts by mass, more preferably 20.0 to 55.0 parts by mass, and further preferably 30.0 to 50.0 parts by mass.

(Aromatic polyester polyol) As for the aromatic polyester polyol, for example, compounds obtained by polycondensation of aromatic polycarboxylic acids and polyols can be listed. The aforementioned aromatic polyester polyols may be a single type or two or more types may be used in combination. As for specific examples of aromatic polycarboxylic acids, phthalic acid, phthalic acid, o-phthalic acid, isophthalic acid, trimellitic acid, hemi-melalic acid, pyromelalic acid and the like aromatic polycarboxylic acids can be listed. As for specific examples of polyols, ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, dipropylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, glycerol, trihydroxymethylpropane, neopentyltritol, sorbitol, bisphenol A and the like can be listed. Examples of the aromatic polyester polyol include those obtained by esterifying polyalkylene terephthalate such as polyethylene terephthalate and polybutylene terephthalate with a polyol.

From the viewpoint of obtaining a rigid polyurethane foam having good flame retardancy, it is preferred that the aforementioned aromatic polyester polyol is contained in the aforementioned polyol compound at the largest ratio. The content of the aforementioned aromatic polyester polyol in the aforementioned polyol compound is preferably 50.0 parts by mass or more, more preferably 60.0 to 100 parts by mass, and further preferably 70.0 to 100 parts by mass in 100 parts by mass of the aforementioned polyol compound.

(Mannich polyol) The Mannich polyol in the present invention refers to an aromatic polyether polyol obtained by addition polymerization of an aromatic polyol obtained by a Mannich reaction of a phenol compound, an aldehyde compound, and an amine compound (Mannich condensate) with an alkylene oxide. The aforementioned Mannich polyol may be a single type or two or more types may be used in combination. For the aforementioned phenol compound, for example, phenol; alkylphenols such as cresol and nonylphenol are generally used. For the aforementioned aldehyde compound, for example, formaldehyde and acetaldehyde are generally used. For the aforementioned amine compound, for example, aliphatic primary or secondary monoamines are listed, and alkanolamines such as monoethanolamine, diethanolamine, and 1-amino-2-propanol; alkylamines such as methylamine and diethylamine are generally used. As for the aforementioned alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide, etc. are generally used. The aforementioned Mannich polyol can be produced by the production method described in International Publication No. 2010/147091, etc.

From the viewpoint of suppressing the aggregation of the powder in the aforementioned polyol composition and obtaining a rigid polyurethane foam having good flame retardancy, when the aforementioned polyol compound contains a Mannich polyol, its content is preferably 1.0 to 20.0 parts by mass, more preferably 2.0 to 15.0 parts by mass, and further preferably 3.0 to 10.0 parts by mass in 100 parts by mass of the aforementioned polyol composition. In addition, from the same viewpoint, the ratio of the content of the aforementioned Mannich polyol to the content of the aforementioned aromatic polyester polyol is preferably 0.10 to 1.00, more preferably 0.15 to 0.90, and further preferably 0.20 to 0.80.

The polyol compound may include, in addition to the aromatic polyester polyol and the Mannich polyol, an aromatic polyether polyol other than the Mannich polyol, but preferably does not include an aliphatic polyol from the viewpoint of obtaining a rigid polyurethane foam having good flame retardancy. From the same viewpoint, the total content of the aromatic polyester polyol and the Mannich polyol in 100 parts by mass of the polyol compound is preferably 90 parts by mass or more, more preferably 95 parts by mass or more, and further preferably 100 parts by mass.

<Flame retardant> The flame retardant used in the polyol composition of the present invention comprises one or more compounds selected from the group consisting of phosphinate metal salts and phosphoric acid metal salts represented by the following formula (1).

In the above formula (1), M is Mg, Al, Ca, Ti or Zn, preferably Al or Zn, more preferably Al. When M is Mg, Ca or Zn, n=2, when M is Al, n=3, when M is Ti, n=4. ^R1 is a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms or a phenyl group, preferably a hydrogen atom, a methyl group, an ethyl group or a phenyl group.

The flame retardant may include either the phosphinic acid metal salt or the phosphate metal salt, or both. From the viewpoint of the effect of the present invention, the flame retardant preferably includes the phosphinic acid metal salt.

The aforementioned phosphinate metal salt is an inorganic phosphinate salt or an organic phosphinate salt and is in powder form. The aforementioned phosphinate metal salt may be a single species or two or more species may be used in combination. The aforementioned powdered flame retardant containing the phosphinate metal salt can impart better flame retardancy to the rigid polyurethane foam compared to conventional flame retardants using red phosphorus or phosphate esters.

The aforementioned phosphoric acid metal salt is an inorganic phosphate or an organic phosphate and is in powder form. As for the aforementioned phosphoric acid metal salt, it is preferably a phosphate ester metal salt. The metal atom (ion) in the aforementioned phosphoric acid metal salt is preferably a salt of the same metal atom (ion) as the aforementioned phosphite metal salt. The aforementioned phosphoric acid metal salt may be a single type or two or more types may be used in combination. The aforementioned phosphoric acid metal salt is also in powder form, and by using a dispersant containing Neuburg silica particles, a good aggregation inhibition effect in the polyol composition is obtained.

From the viewpoint of further improving flame retardancy, the flame retardant may contain, in addition to the phosphinate metal salt or phosphoric acid metal salt, a component that can function as a flame retardant aid, preferably a nitrogen-containing compound. Examples of the nitrogen-containing compound include melamine, melamine phosphate, melamine pyrophosphate, melamine polyphosphate, melamine phthalate, melamine cyanurate, benzoguanidine, and melamine cyanurate. Among them, only one or more kinds may be included. When the flame retardant contains a nitrogen-containing compound, its content is preferably 200 parts by mass or less, more preferably 100 parts by mass or less, and further preferably 50 parts by mass or less, relative to 100 parts by mass of the phosphinate metal salt.

However, ammonium polyphosphate is not suitable because it tends to delay the urethanization reaction during the production of hard polyurethane foam. Ammonium polyphosphate is easily gelled in the polyol composition and is not good at inhibiting aggregation. In addition, in the polyol composition, phosphoric acid ions are easily freed, and the free acid affects the catalyst activity in the urethanization reaction. It is estimated that the urethanization reaction is not sufficiently promoted, and a hard polyurethane foam with good flame retardancy cannot be obtained.

In the present invention, as the powdery flame retardant containing the phosphinic acid metal salt and the nitrogen-containing compound, for example, commercially available products such as "FRAN CM" series manufactured by Yamato Chemical Industries, Ltd. can be suitably used.

Furthermore, from the perspective of obtaining a rigid polyurethane foam having good flame retardancy, the powdered flame retardant containing a phosphinate metal salt and/or a phosphoric acid metal salt is preferably 50 parts by mass or more, more preferably 52 to 100 parts by mass, and further preferably 55 to 100 parts by mass out of a total of 100 parts by mass of the flame retardant in the polyol composition. Furthermore, in view of the fact that the powdered flame retardant containing the phosphinate metal salt and/or the phosphate metal salt is easily precipitated and agglomerated, the solid content of the powdered flame retardant, i.e., the flame retardant, is preferably 10.0 to 40.0 parts by mass, more preferably 12.0 to 35.0 parts by mass, and further preferably 15.0 to 30.0 parts by mass, based on 100 parts by mass of the polyol composition.

The flame retardant mentioned above may include liquid phosphate esters from the viewpoint of obtaining the effect of suppressing carbonization in the initial stage when the rigid polyurethane foam is heated or burned. For example, tris(β-chloropropyl) phosphate, which is a halogen-containing phosphate ester, is generally used. Tris(β-chloropropyl) phosphate is a liquid and will not condense in the raw material liquid of the rigid polyurethane foam like the aforementioned powdered phosphinic acid metal salts or phosphoric acid metal salts and red phosphorus. However, the effect of imparting flame retardancy to the rigid polyurethane foam is better with the aforementioned phosphinic acid metal salts. Therefore, when the flame retardant contains liquid phosphate, its content is preferably 50 parts by mass or less, more preferably less than 50 parts by mass, and further preferably 45 parts by mass or less, based on 100 parts by mass of the flame retardant.

<Dispersant> The dispersant in the aforementioned polyol composition includes Neuburg silica particles. The Neuburg silica particles in the present invention refer to a natural combination of cryptomicrocrystalline and amorphous silica in particle form and kaolin in plate form, also called Sillitin or Sillikolloid. For example, it can be obtained as products such as Sillitin V85, Sillitin V88, Sillitin N82, Sillitin N85, Sillitin N87, Sillitin Z86, Sillitin Z89, Sillikolloid P87, etc. from Hoffman Minerals.

Although Neuburg silica particles themselves are insoluble in the aforementioned polyol composition, by using the Neuburg silica particles as a dispersant, even if the aforementioned phosphite metal salt and/or phosphoric acid metal salt in powder form of a flame retardant is precipitated, the precipitated powder is difficult to agglomerate and can be easily redispersed. Therefore, when manufacturing a flame retardant rigid polyurethane foam, by adding Neuburg silica particles to the polyol composition, the burden of uniformly mixing the polyol composition and the raw material liquid of the flame retardant rigid polyurethane foam can be reduced, and the uniform dispersibility of the powder in the aforementioned raw material liquid can be improved.

From the perspective of more effectively inhibiting the aggregation of the powder in the aforementioned polyol composition, the aforementioned dispersant may contain, in addition to Neuburg silica particles, a surfactant that exerts an aggregation inhibition effect. From the perspective of effectively inhibiting the aggregation of the powder in the aforementioned polyol composition and imparting good flame retardancy to the rigid polyurethane foam, the content of Neuburg silica particles in the aforementioned dispersant is preferably 90 parts by mass or more, more preferably 95 to 100 parts by mass, and further preferably 100 parts by mass in 100 parts by mass of the dispersant. From the same point of view, the content of Neuburg silica particles is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass, and further preferably 10 to 20 parts by mass, relative to 100 parts by mass of the total solid content in the aforementioned flame retardant.

<Other ingredients> As for the raw materials for manufacturing the flame retardant rigid polyurethane foam, in addition to the polyol compound, flame retardant and polyisocyanate compound as the main raw materials, a foaming agent, a catalyst, a foam stabilizer, etc. may also be mixed. These ingredients can be added separately from the polyol composition during the manufacture of the flame retardant rigid polyurethane foam, but from the perspective of reducing the work burden at the manufacturing site of the flame retardant rigid polyurethane foam, it is better to mix them in the aforementioned polyol composition. Furthermore, the aforementioned polyol composition may contain additives such as solvents, colorants, antioxidants, etc. as necessary within the range that does not hinder the effect of the present invention.

(Foaming agent) The foaming agent is a foaming agent that generates gas by heat generated by the resinification reaction of the polyol compound and the polyisocyanate compound to form urethane bonds, and foams the polyurethane resin. As for the aforementioned foaming agent, for example, hydrofluoroolefin (HFO), hydrochlorofluoroolefin (HCFO), hydrofluorocarbon (HFC), water, etc. can be listed. These can be used alone or in combination of two or more. Among these, HFO and HCFO will replace HFC and are foaming agents that are expected to be needed in the future from the perspective of global warming suppression effects, so it is better to use these. Specifically, trans-1,3,3,3-tetrafluoropropene (trans-HFO-1234ze), 1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz), trans-1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), and the like can be cited.

The isocyanate group of the polyisocyanate compound also reacts with water to generate a urea bond and a foaming reaction to generate carbonic acid gas. Water serves as a foaming inducer in the initial stage of the reaction to generate the rigid polyurethane foam and can reduce the density of the manufactured rigid polyurethane foam. Therefore, it is preferred to include water as a foaming agent.

From the viewpoint of appropriately foaming the polyurethane resin, the blending amount of the aforementioned foaming agent is preferably 5.0 to 40.0 parts by mass, more preferably 10.0 to 30.0 parts by mass, and further preferably 12.0 to 25.0 parts by mass relative to 100 parts by mass of the polyisocyanate compound. However, water may hydrolyze the aromatic polyester polyol, so its content is preferably less than that of other foaming agents. It is preferably 20.0 parts by mass or less, more preferably 0.8 to 15.0 parts by mass, and further preferably 1.0 to 10.0 parts by mass relative to 100 parts by mass of the total foaming agent other than water.

(Catalyst) From the perspective of promoting the aforementioned resinification reaction and foaming reaction, a tertiary amine catalyst is suitable for the reaction of forming a rigid polyurethane foam. From the perspective of improving flame retardancy due to partial nuration, a nurating catalyst can also be used. As such catalysts, catalysts known in the production of rigid polyurethane foam can be used. One of these catalysts may be used alone, or two or more of them may be used in combination.

As for the tertiary amine catalyst, for example, dimethylethanolamine, triethylenediamine, methyldicyclohexylamine, dimethylcyclohexylamine, pentamethyldiethylenetriamine, bis(2-dimethylaminoethyl)ether, diethylmethylphenylenediamine, 1,2-dimethylimidazole, 1,4-diazobicyclo[2.2.2]octane, etc. can be cited. From the viewpoint of appropriately promoting the resinification reaction and foaming reaction of the rigid polyurethane foam, the blending amount of the tertiary amine catalyst is preferably 0.1 to 10.0 parts by mass, more preferably 0.2 to 8.0 parts by mass, and further preferably 0.5 to 5.0 parts by mass, relative to 100 parts by mass of the polyisocyanate compound.

As for the aforementioned isocyanurate catalyst, for example, tris(dimethylaminomethyl)phenol, 2,4-bis(dimethylaminomethyl)phenol, 2,4,6-tris(dialkylaminoalkyl)hexahydro-S-triol, ; alkali metal salts of carboxylates such as potassium acetate and potassium 2-ethylhexylate; tertiary ammonium salts such as trimethylammonium salt, triethylammonium salt and triphenylammonium salt; quaternary ammonium salts such as tetramethylammonium salt, tetraethylammonium and tetraphenylammonium salt. From the viewpoint of appropriately promoting the isocyanuration reaction of isocyanate, the amount of the isocyanuration catalyst is preferably 0.05 to 10.0 parts by mass, more preferably 0.1 to 8.0 parts by mass, and further preferably 0.2 to 5.0 parts by mass, relative to 100 parts by mass of the polyisocyanate compound.

(Foam stabilizer) From the viewpoint of obtaining a homogeneous flame-retardant rigid polyurethane foam, a foam stabilizer known in the production of rigid polyurethane foam can be used as the blended foam stabilizer. Generally speaking, silicone foam stabilizers are suitable, and for example, siloxane-polyalkylene oxide copolymers can be listed. The blending amount of the aforementioned foam stabilizer is appropriately set according to the type of polyurethane resin to be generated, but is preferably 0.05 to 10.0 parts by mass, more preferably 0.1 to 8.0 parts by mass, and further preferably 0.2 to 5.0 parts by mass relative to 100 parts by mass of the polyisocyanate compound.

Furthermore, the aforementioned polyol composition may contain additives such as solvents, fillers, colorants, antioxidants, etc. as necessary within the range that does not hinder the effects of the present invention.

[Flame retardant rigid polyurethane foam] The flame retardant rigid polyurethane foam of the present invention is a reaction product obtained by reacting the aforementioned polyol composition with a polyisocyanate compound. When a polyol composition that is not sufficiently uniform is used, it is difficult to obtain a homogeneous rigid polyurethane foam having overall good flame retardancy. In contrast, according to the polyol composition of the present invention, as described above, when a powdered flame retardant containing the aforementioned phosphinate metal salt and/or phosphoric acid metal salt that is easily agglomerated is used, the aggregation of the powder can be effectively suppressed in the raw material liquid of the polyol composition and the flame retardant rigid polyurethane foam. According to this, when manufacturing the flame retardant rigid polyurethane foam, the work burden for uniformly dispersing the polyol composition and the raw material liquid of the flame retardant rigid polyurethane foam can be reduced, and the uniform dispersion of the powder in the raw material liquid can be improved. In addition, the good flame retardancy caused by the flame retardant in the obtained flame retardant rigid polyurethane foam can be maintained.

<Polyisocyanate compound> The polyisocyanate compound is an isocyanate compound having two or more isocyanate groups, and generates a polyurethane resin by an addition polymerization reaction with the aforementioned polyol compound. The aforementioned polyisocyanate compound may be either an aromatic polyisocyanate or an aliphatic polyisocyanate, and one of them may be used alone or two or more of them may be used in combination.

As for aromatic polyisocyanates, for example, diphenyl ether-2,4'-diisocyanate, diphenyl ether-4,4'-diisocyanate, methylphenyl-2,4-diisocyanate, methylphenyl-2,6-diisocyanate, 4,6-dimethyl-1,3-phenylene diisocyanate, 2,2'-diphenylmethane diisocyanate (2,2'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), etc., monomeric MDI, polymethylene polyphenyl polyisocyanate (crude MDI or polymeric MDI), 3,3'-dimethyl-4,4'-biphenylene diisocyanate, m-xylene isocyanate, etc. can be cited. As for the aliphatic polyisocyanate, it may be any of non-cyclic or alicyclic polyisocyanates, for example, tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, etc. Among them, from the viewpoint of reactivity and flame retardancy of the manufactured rigid polyurethane foam, monomeric MDI, crude MDI or polymeric MDI such as 2,2'-MDI, 2,4'-MDI, 4,4'-MDI is preferred, and from the viewpoint of easy acquisition and cost, crude MDI or polymeric MDI is suitable.

The amount of the polyisocyanate compound blended in the raw material liquid of the flame retardant rigid polyurethane foam is appropriately set depending on the type of the polyisocyanate compound, but is preferably 50 to 200 parts by mass, more preferably 70 to 150 parts by mass, and further preferably 80 to 120 parts by mass based on 100 parts by mass of the polyol composition from the viewpoint of sufficient reactivity with the polyol compound and ease of handling when mixing the raw material liquid.

<Method for producing flame-retardant rigid polyurethane foam> The molding and foaming method in the method for producing the flame-retardant rigid polyurethane foam is not particularly limited, and known methods such as slab molding, mold-molding, lamination molding, injection molding, and spray foaming can be applied. In each of these molding and foaming methods, a homogeneous rigid polyurethane foam having good flame retardancy can be produced by mixing the polyol composition and the polyisocyanate compound, foaming and curing them.

As described above, since the aggregation of the powder contained is suppressed, the aforementioned polyol composition can be easily made uniform when it is redispersed when mixed with the polyisocyanate compound, for example, by using a general stirrer using a stirring blade, without requiring a large shear force. In other words, it can be easily made uniformly redispersed with less work burden. Therefore, by using the aforementioned polyol composition, the efficiency of the production of flame-retardant rigid polyurethane foam can be sought. [Example]

Hereinafter, the present invention will be described in detail by way of embodiments, but the present invention is not limited thereto.

[Preparation of polyol composition] The following presents the details of each raw material used in the preparation of the polyol composition of the following examples and comparative examples. ＜Polyol compounds＞ (Polyester polyol) ・RFK-556: terephthalic acid polyester polyol; "MAXIMOL (registered trademark) RFK-556", manufactured by Kawasaki Chemical Industries, Ltd., hydroxyl value 224mgKOH/g (Mannich polyol) ・NB-622: "EXCENOL (registered trademark) NB-622", manufactured by AGC Co., Ltd., hydroxyl value 500mgKOH/g ＜Flame retardant＞ (a1) CM-6R: Powdered flame retardant containing phosphinate metal salt; "FRAN CM -6R", manufactured by Yamato Chemical Industries, Ltd. (a2) OP935: Phosphinate metal salt; "Exolit (registered trademark) OP935", Clariant Chemicals Co., Ltd. (a3) R098-5: Phosphate metal salt (powder); "Nonnen (registered trademark) R098-5", Maruryoshi Chemical Co., Ltd. (a'1) ・TK-1000: Ammonium polyphosphate; "TK-1000", MANAC Co., Ltd. ・TMCPP: Tris(β-chloropropyl) phosphate; "TMCPP", Daihachi Chemical Co., Ltd. <Dispersant> (Neuburg silica particles) (b1) P87: "Sillikolloid P87", Hoffman Mineral Co., Ltd. (b2) V85: "Sillitin V85", Hoffman Mineral Co., Ltd. (Carbon black) ・MA220: "Carbon black MA220", manufactured by Mitsubishi Chemical Co., Ltd. <Foaming agent> ・HCFO: trans-1-chloro-3,3,3-trifluoropropene (HCFO-1233zd); "Solstice (registered trademark) LBA", manufactured by Honeywell International Inc. ・Water <Catalyst> ・SX60: tertiary amine catalyst; "TOYOCAT (registered trademark)-SX60", manufactured by TOSOH Co., Ltd. ・DM70: tertiary amine catalyst; "TOYOCAT (registered trademark)-DM70", manufactured by TOSOH Co., Ltd. ・K-15: potassium 2-ethylhexanoate; "Dabco (registered trademark) K-15", manufactured by Evonik, isocyanurate catalyst ＜Foam stabilizer＞ ・L-6100: Silicone foam stabilizer; "Niax (registered trademark) silicone L-6100", manufactured by Momentive Performance Materials Inc.

(Example 1) In a 500 mL polyethylene bottle, 35.2 parts by mass of polyester polyol RFK-556, 1.6 parts by mass of catalysts (SX60, DM70 and K-15), 0.3 parts by mass of water (foaming agent), 15.6 parts by mass of TMCPP, and 1.6 parts by mass of foam stabilizer were placed, and stirred at 3000 rpm for 20 seconds using an electric drill equipped with a cage-type stirrer (the stirring method is the same below). 20.0 parts by mass of a flame retardant (a1) and 2.0 parts by mass of Neuburg silica particles (b1) were added thereto, and stirred for 20 seconds. Then, 20.5 parts by mass of HCFO was added, and stirred for another 20 seconds. The mixture was then kept warm in a constant temperature water bath at 20° C. to prepare a polyol composition.

(Examples 2 to 6, Comparative Examples 1 to 6) The raw materials shown in Table 1 below were mixed and the same process as in Example 1 was performed to prepare respective polyol compositions. In Comparative Example 2, when the flame retardant was red phosphorus, carbon black, which is well known as a sedimentation inhibitor, was used as a dispersant.

[Manufacturing of rigid polyurethane foam] Using the polyol compositions of the above-mentioned embodiments and comparative examples, rigid polyurethane foam was manufactured in the following manner. In addition, as for the polyisocyanate compound, polymethylene polyphenyl polyisocyanate (MDI of polymer) was used; "MILLIONATE (registered trademark) MR-200", manufactured by TOSOH Co., Ltd. In a 500 mL recyclable measuring cup, 100 parts by mass of the polyol composition and 102.5 parts by mass of the polyisocyanate compound in a uniformly stirred state were placed, stirred for 5 seconds, and then the obtained mixed solution (raw material solution of rigid polyurethane foam) was poured into a square mold of 15 cm square, allowed to stand for 30 minutes, and then demolded to obtain a rigid polyurethane foam.

[Evaluation] The polyol compositions prepared in the above-mentioned embodiments and comparative examples and the rigid polyurethane foams produced using the polyol compositions were evaluated for the following items. The evaluation results are summarized and presented in the following Table 1.

<Cohesion> After a 50 mL vial containing 30 g of the polyol composition was left at room temperature (25°C) for 21 days, the vial was placed on its side for 5 minutes and then placed upright for 5 minutes. The state of the sediment of the solid content was confirmed by visual observation. The observation results were evaluated based on the following evaluation criteria. (Evaluation criteria) AA: When the vial was placed on its side, the sediment flowed, and when it was placed upright again, it returned to its original state within 1 minute. A: When the vial was placed on its side, the sediment flowed, and when it was placed upright again, it slowly returned to its original state. Even if it was placed on its side for 5 minutes, the sediment did not return to its original state at all, but it did not adhere to the inner wall surface of the vial. B: When the vial is turned sideways, the sediment flows, and when it is upright again, it slowly returns to its original state. Even if it is left still for 5 minutes, the sediment does not return to its original state at all, but there are residues attached to the inner wall of the vial. C: Even if the vial is turned sideways, the sediment does not flow. D: The solid content is gelled. In the case of evaluation AA or A, it can be said that the aggregation of the powder is well suppressed, and in the case of evaluation AA, it can be said that the aggregation suppression effect is particularly excellent. On the other hand, in the cases of evaluation B to D, it is judged that a sufficient aggregation suppression effect is not obtained, and in the cases of evaluation C and D, it is judged that it is not suitable for practical use.

<Flammability> From the rigid polyurethane foam produced above, a sample of 98mm×98mm×thickness (height) 25mm was cut. According to ISO 5660-1, a cone calorimeter ("Cone calorimeter III", manufactured by Toyo Seiki Seisakusho Co., Ltd.; non-combustible material of the base material: gypsum board (thickness 9.5mm)) was used to apply 50KW/ ^m2 of heat to the sample through the cone, and at the same time, it was ignited for 10 seconds by a spark plug, and the total heat generated after heating for 20 minutes was measured. These measured values were evaluated based on the following evaluation criteria. (Evaluation criteria) A: Total calorific value less than 8MJ/ ^m2 B: Total calorific value 8MJ/m2 ^or more and less than 11MJ/ ^m2 C: Total calorific value 11MJ/ ^m2 or more and less than 20MJ/ ^m2 D: Total calorific value 20MJ/m2 ^{or more} In the case of evaluation A, the flame retardancy is the highest and can be regarded as a non-combustible material. Next, in the case of evaluation B, the flame retardancy is also sufficiently high and can be regarded as a quasi-non-combustible material.

[Table 1] Blending composition [mass] Embodiment Comparison Example 1 2 3 4 5 6 1 2 3 4 5 6 Polyol compounds Polyester polyol RFK-556 35.2 27.4 27.1 27.4 27.4 27.4 36.5 27.4 36.5 36.5 36.5 35.5 Mannich polyol NB-622 - 7.8 7.6 7.8 - - - 7.8 - - - - Flame retardant Phosphinic acid metal salt or phosphoric acid metal salt (a) (a1)CM-6R 20.0 20.0 20.0 20.0 - - 20.0 20.0 - - - - (a2)OP935 - - - - 30.0 - - - 30.0 - - - (a3)R098-5 - - - - - 30.0 - - - 30.0 - - Ammonium Polyphosphate (a'1)TK-1000 - - - - - - - - - - 30.0 30.0 TMCPP 15.6 15.6 15.2 15.6 13.4 13.4 16.0 15.6 6.0 6.0 6.0 6.0 Dispersants Neuburg silica particles (b) (b1)P87 2.0 2.0 4.0 - 2.0 2.0 - - - - - 2.0 (b2)V85 - - - 2.0 - - - - - - - - ((b)/(a)×100) (10) (10) (20) (10) (10) (10) - - - - - (10) Carbon Black MA220 - - - - - - - 2.0 - - - - Foaming agent HCFO 20.5 20.5 19.8 20.5 20.5 20.5 20.8 20.5 20.8 20.8 20.8 19.8 water 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Catalyst SX60 1.6 1.6 1.5 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 DM70 1.6 1.6 1.5 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 K-15 1.6 1.6 1.5 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 Foam Stabilizer L-6100 1.6 1.6 1.5 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 Cohesion A AA AA AA AA AA B C B B D C Flame retardancy A A B B B B A B B B C C

From the results shown in Table 1, it is confirmed that by adding Neuburg silica particles as a dispersant (Examples 1 to 6), the aggregation of a powdered flame retardant containing one or more compounds selected from the group containing specified phosphinate metal salts and phosphate metal salts is suppressed, and a rigid polyurethane foam having a flame retardancy equivalent to or higher than that of a quasi-incombustible material is obtained. When Mannich polyol is used in combination as a polyol compound (Examples 2 to 4), it is confirmed that a particularly excellent aggregation inhibition effect is obtained. On the other hand, in the case where Neuburg silica particles were not added (Comparative Examples 1, 3, and 4) and where carbon black was added as a dispersant (Comparative Example 2), the flame retardancy of the rigid polyurethane foam was good, but the effect of suppressing the aggregation of the powder in the polyol composition was not sufficient. In addition, in the case where the flame retardant contained ammonium polyphosphate (Comparative Examples 5 and 6), the polyol composition was gelled or solidified, and the flame retardancy of the rigid polyurethane foam was also poor.

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Claims (9)

A polyol composition is a polyol composition for producing a flame retardant rigid polyurethane foam, comprising: a polyol compound including an aromatic polyester polyol; a flame retardant including one or more compounds selected from the group consisting of phosphinic acid metal salts and phosphoric acid metal salts represented by the following formula (1); and a dispersant including Neuburg Siliceous Earth particles.

(In formula (1), M is Mg, Al, Ca, Ti or Zn, ^R1 is a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms or a phenyl group, and n is 2, 3 or 4). A polyol composition as claimed in claim 1, wherein the polyol compound comprises a Mannich polyol. The polyol composition of claim 1 or 2, wherein the Neuburg silica particles are contained in an amount of 1 to 50 parts by weight relative to a total of 100 parts by weight of the solid content in the flame retardant. The polyol composition of claim 1 or 2 contains a foaming agent. The polyol composition of claim 4, wherein the blowing agent comprises one or more of hydrofluoroolefins and hydrochlorofluoroolefins. The polyol composition of claim 1 or 2 comprises a catalyst. The polyol composition of claim 1 or 2 contains a foam stabilizer. A flame retardant rigid polyurethane foam, which is a reaction product of a polyol composition as described in any one of claims 1 to 7 and a polyisocyanate compound. A method for producing a flame retardant rigid polyurethane foam, comprising mixing a polyol composition as described in any one of claims 1 to 7 with a polyisocyanate compound, foaming and curing the mixture, and obtaining the flame retardant rigid polyurethane foam.