Polyether polyol, method for producing the same, composition for rigid polyurethane foam, rigid polyurethane foam, and method for producing the same

Abstract

To provide a polyether polyol that can give a hard polyurethane foam having excellent flame retardancy.SOLUTION: A polyether polyol is an alkylene oxide adduct of a resol type phenol resin. In the resol type phenol resin, the number of methylol groups is 0.25 or less per phenol skeleton.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polyether polyol, a method for producing the same, a composition for a rigid polyurethane foam, a rigid polyurethane foam, and a method for producing the same.

Background Art

[0002] Rigid polyurethane foams are widely used in a wide range of applications such as building materials, heat insulating materials for refrigerators and freezers, structural materials, and sprays for on-site building construction because of their excellent heat insulating performance, dimensional stability at low temperatures, and workability. Conventionally, flame retardation of rigid polyurethane foams has been attempted by using flame retardants (Non-Patent Document 1). However, when a large amount of flame retardant is used, there is a problem that mechanical properties such as the compressive strength of the rigid polyurethane foam deteriorate, and there is a limit to flame retardation. On the other hand, flame retardation of rigid polyurethane foams has also been attempted from the viewpoint of raw materials for rigid polyurethane foams. Patent Document 1 proposes a method for improving the flame retardancy of polyurethane foams by using a polyester polyol obtained by esterifying phthalic acid or the like as a polyol for raw materials.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the flame retardancy of the rigid polyurethane foam using the polyether polyol described in Patent Document 1 is not sufficient. An object of the present invention is to provide a polyether polyol and a composition for a rigid polyurethane foam capable of obtaining a rigid polyurethane foam excellent in flame retardancy, a production method capable of producing the polyether polyol, and a rigid polyurethane foam excellent in flame retardancy and a production method thereof.

Means for Solving the Problems

[0006] The present invention has the following aspects. [1] An alkylene oxide adduct of a resol type phenol resin, A polyether polyol in which the number of methylol groups per phenol skeleton in the resol type phenol resin is 0.25 or less. [2] The polyether polyol according to [1], wherein the resol type phenol resin contains 5 to 50% by mass of free phenols based on the total mass of the resol type phenol resin. [3] The polyether polyol according to [1] or [2], wherein the resol type phenol resin contains 0 to 0.3% by mass of water based on the total mass of the resol type phenol resin. [4] The polyether polyol according to any one of [1] to [3], having a viscosity at 25°C of 100 to 35000 mPa·s. [5] The polyether polyol according to any one of [1] to [4], having a hydroxyl value of 200 to 400 mgKOH / g. [6] The polyether polyol according to any one of [1] to [5], wherein the alkylene oxide is ethylene oxide, propylene oxide or a mixture thereof. [7] A method for producing the polyether polyol according to any one of [1] to [6], A method for producing a polyether polyol, comprising a step of reacting the resol type phenol resin with the alkylene oxide. [8]Before the step of reacting the resol type phenol resin with the alkylene oxide, the method includes a step of producing the resol type phenol resin, In the step of producing the resol type phenol resin, phenols and aldehydes are reacted in the presence of an alkali catalyst, the obtained reaction product is neutralized to adjust the pH to 7.0 to 9.0, and the obtained neutralized product is subjected to a methylol group reduction treatment. The production method according to [7] above. [9]It contains a polyol component, a catalyst, and a foaming agent, The composition for rigid polyurethane foam, wherein the polyol component contains any one of the polyether polyols of [1] to [6] above.

[10] It contains a reaction product of a polyol component and a polyisocyanate component, The rigid polyurethane foam, wherein the polyol component contains any one of the polyether polyols of [1] to [6] above.

[11] The method for producing a rigid polyurethane foam includes a step of reacting a polyol component and a polyisocyanate component in the presence of a catalyst and a foaming agent, The method for producing a rigid polyurethane foam, wherein the polyol component contains any one of the polyether polyols of [1] to [6] above.

Advantages of the Invention

[0007] According to the present invention, a polyether polyol and a composition for rigid polyurethane foam capable of obtaining a rigid polyurethane foam excellent in flame retardancy, a production method capable of producing a polyether polyol capable of obtaining a rigid polyurethane foam excellent in flame retardancy, and a rigid polyurethane foam excellent in flame retardancy and a production method thereof can be provided.

Embodiments for Carrying Out the Invention

[0008] [Polyether Polyol] The polyether polyol according to one aspect of the present invention (hereinafter, also referred to as "polyol (A)") is an alkylene oxide (hereinafter, also referred to as "AO") adduct of a resol type phenol resin (hereinafter, also referred to as "resol resin"). The resol resin and AO will be described in detail later.

[0009] The hydroxyl value of the polyol (A) is preferably 200 to 400 mgKOH / g, more preferably 250 to 390 mgKOH / g. If the hydroxyl value is at least the above lower limit, sufficient hardness can be easily obtained as a rigid polyurethane foam, and if it is at most the above upper limit, the viscosity can be lowered. The hydroxyl value is the number of milligrams (mg) of potassium hydroxide equivalent to the hydroxyl groups in 1 g of the sample. The hydroxyl value is determined by the method B described in JIS K 1557-1. The hydroxyl value of the polyol (A) can be adjusted by the addition amount of AO.

[0010] The addition amount of AO can be appropriately set according to the target hydroxyl value, but it is preferably 1 to 4 moles, more preferably 1 to 3 moles, per active hydrogen atom of the resol resin. If the addition amount of AO is within the above range, it is easy to make the hydroxyl value of the polyol (A) within the above preferred range.

[0011] The viscosity of the polyol (A) at 25°C is preferably 100 to 35000 mPa·s, more preferably 500 to 10000 mPa·s, and even more preferably 1000 to 6000 mPa·s. If the viscosity is at least the above lower limit, sufficient hardness can be easily obtained as a rigid polyurethane foam, and if it is at most the above upper limit, it is easy to mix with other materials (such as polyisocyanate components). The viscosity of the polyol (A) is measured by a B-type viscometer.

[0012] The aromatic ring concentration of the polyol (A) is preferably 30 to 60% by mass, more preferably 35 to 55% by mass. If the aromatic ring concentration is at least the above lower limit, the mass residual rate of the polyol (A) is more excellent, and if it is at most the above upper limit, it is easy to make the viscosity of the polyol (A) within the above preferred range. The aromatic ring concentration is the mass ratio of the benzene rings in the polyol (A) to the mass of the polyol (A). The mass of the benzene rings in the polyol (A) is determined by the calculation formula described later.

[0013] The polyol (A) preferably has a mass retention rate of 10% by mass or more, more preferably 20% by mass or more when heated to 500°C in thermogravimetric analysis. If the mass retention rate is at least the above lower limit, the polyol (A) has high heat resistance and the resulting rigid polyurethane foam has more excellent flame retardancy. The detailed measurement method of the mass retention rate is as described in the examples below.

[0014] <Resole resin> The resole resin is a resin obtained through a process of reacting phenols and aldehydes in the presence of an alkali catalyst, and contains the reaction product of phenols and aldehydes. When phenols and aldehydes are reacted in the presence of an alkali catalyst, an addition reaction occurs in which aldehydes are added to the aromatic ring of the phenols, and a methylol form having a methylol group is generated. Then, it polymerizes through a condensation reaction between the methylol forms.

[0015] As the resole resin which is the starting material of the polyol (A), those having 0.25 or less methylol groups per phenol skeleton in the resole resin (hereinafter also referred to as "methylol group amount") are used. The methylol group amount is preferably 0.2 or less, more preferably 0.1 or less, and may be 0. The methylol group amount of a general resole resin is more than 0.25. When the methylol group amount is more than 0.25, when reacting the resole resin with AO, the condensation reaction of the resole resin tends to proceed along with the addition reaction of AO. When the condensation reaction proceeds, moisture is generated, and the target reaction is difficult to proceed, such as the reaction between water and AO to generate by-products. If the methylol group amount is 0.25 or less, the addition reaction of AO to the resole resin easily proceeds. To make the methylol group amount 0.25 or less, for example, after reacting phenols and aldehydes in the presence of an alkali catalyst, a methylol group reduction treatment is performed. The methylol group reduction treatment will be described in detail later.

[0016] The resol resin is typically in a liquid state. The viscosity of the resol resin at 25°C is preferably 10 to 20,000 mPa·s, more preferably 100 to 10,000 mPa·s. If the viscosity of the resol resin is within the above range, the viscosity of the polyol (A) is likely to be within the above-mentioned preferred range. The viscosity of the resol resin is measured by an E-type viscometer.

[0017] The resol resin preferably contains free phenols. The free phenols are unreacted phenols measured in accordance with the provisions of 5.16 of JIS K 6910. The content of the free phenols is preferably 5 to 50% by mass, more preferably 25 to 45% by mass, and even more preferably 35 to 45% by mass based on the total mass of the resol resin. If the content of the free phenols is at least the above lower limit, the viscosity of the resol resin, and thus the viscosity of the polyol (A), will be sufficiently low, making it easy to foam during the production of rigid polyurethane foam. If the content of the free phenols is at most the above upper limit, it is easy to obtain sufficient hardness as a rigid polyurethane foam.

[0018] The resol resin may contain moisture. The content of the moisture is preferably 0 to 0.3% by mass, more preferably 0 to 0.15% by mass, and even more preferably 0 to 0.05% by mass based on the total mass of the resol resin. If the content of the moisture is at most the above upper limit, the addition reaction of AO to the resol resin proceeds easily. Containing 0% by mass of moisture means not containing moisture. The content of the moisture is measured by the Karl Fischer method (for example, using "AQV-2200" manufactured by HIRANUMA Co., Ltd. and the measuring reagent "Hydranal Composite 5" manufactured by Honeywell).

[0019] (Method for producing resol resin) A resol resin can be produced, for example, by reacting phenols and aldehydes in the presence of an alkali catalyst, neutralizing the resulting reaction product to a pH of 7.0 to 9.0, and subjecting the resulting neutralized product to a methylol group reduction treatment.

[0020] Phenols are compounds having an aromatic ring and a hydroxyl group bonded to the aromatic ring. Examples include phenol, alkylphenols (o-, m-, p-cresols, o-, m-, p-ethylphenols, isomers of xylenol, etc.), polyaromatic ring phenols (α-, β-naphthols, etc.), polyhydric phenols (bisphenol A, bisphenol F, bisphenol S, pyrogallol, resorcinol, catechol, hydroquinone, etc.). These phenols may be used alone or in combination of two or more. Among these, practical substances are phenol, o-, m-, p-cresols, isomers of xylenol, resorcinol, and catechol.

[0021] Aldehydes are at least one compound selected from the group consisting of compounds having a formyl group and their multimers. Examples include formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, salicylaldehyde, glyoxal, etc. These aldehydes may be used alone or in combination of two or more. Among these, practical substances are formaldehyde and paraformaldehyde.

[0022] The molar ratio of aldehydes to phenols (aldehydes / phenols) (hereinafter also referred to as "F / P") is preferably 0.1 to 0.8, more preferably 0.2 to 0.5. However, when the aldehyde is a multimer such as paraformaldehyde, F / P is the value in terms of monomer conversion. If F / P is at least the above lower limit value, odor generation and yield reduction due to volatilization of free phenols can be suppressed. If F / P is at most the above upper limit value, no large amount of free aldehydes will remain, and formaldehyde will not volatilize in the working environment atmosphere during the manufacturing process, and the health of workers will not be harmed. Free aldehydes are unreacted aldehydes measured in accordance with the provisions of 5.17 of JIS K 6910.

[0023] The alkali catalyst is not particularly limited as long as it can promote the reaction between phenols and aldehydes, and various alkaline substances can be used. Specific examples include hydroxides of alkali metals such as sodium and potassium (sodium hydroxide, potassium hydroxide, etc.), hydroxides of alkaline earth metals such as calcium, magnesium, and barium (calcium hydroxide, magnesium hydroxide, barium hydroxide, etc.), inorganic alkaline substances such as sodium carbonate and ammonia; organic alkaline substances such as tertiary amines such as triethylamine, trimethylamine, and triethanolamine, and cyclic amines such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5-diazabicyclo[4.3.0]nona-5-ene (DBN); etc. These alkali catalysts may be used alone or in combination of two or more. The amount of the alkali catalyst used can be, for example, 0.1 to 5 parts by mass with respect to 100 parts by mass of phenols.

[0024] The method of reacting phenols and aldehydes in the presence of an alkali catalyst may be a known method. For example, a method of charging phenols, aldehydes, an alkali catalyst, water, etc. into a reaction vessel equipped with a stirring device and maintaining an arbitrary reaction temperature for an arbitrary reaction time can be mentioned. After the start of the reaction, additional alkali catalyst and arbitrary additives, etc. may be added as necessary.

[0025] The reaction temperature is preferably 50 to 110°C, more preferably 60 to 90°C. If the reaction temperature is at or above the lower limit value of the above range, a sufficient reaction rate can be obtained. If the reaction temperature is at or below the upper limit value of the above range, the reaction is easy to control. The reaction time can be, for example, 1 to 8 hours, and further 2 to 6 hours. If the reaction time is within the above range, it is easy to control the amount of methylol and the molecular weight.

[0026] As the acid used for neutralization after reacting phenols and aldehydes in the presence of an alkali catalyst, any acid capable of neutralizing the alkali catalyst may be used, and examples thereof include boric acid, sulfuric acid, hydrochloric acid, phosphoric acid, lactic acid, formic acid, and the like. The pH of the neutralized product is 7.0 to 9.0, preferably 7.0 to 8.0.

[0027] Examples of the methylol group reduction treatment include a treatment of heating the neutralized product at 120 to 150 °C for 1 to 4 hours. Thereby, the methylol group is reduced by the condensation reaction between the methylol group and phenols. If necessary, after the methylol group reduction treatment or simultaneously with the methylol group reduction treatment, treatments such as dilution, concentration (dehydration), and dephenolization may be performed.

[0028] <Alkylene Oxide (AO)> The number of carbon atoms of AO is, for example, 2 to 12, preferably 2 to 8. Specific examples of AO include ethylene oxide (hereinafter also referred to as "EO"), propylene oxide (hereinafter also referred to as "PO"), 1,2-, 2,3- or 1,3-butylene oxide (hereinafter also referred to as "BO"), tetrahydrofuran, 3-methyl-tetrahydrofuran, 1,3-propylene oxide, iso-BO, α-olefin oxides having 5 to 12 carbon atoms, substituted AO (for example, epihalohydrins such as epichlorohydrin, styrene oxide, etc.) and mixtures of two or more thereof. In the case of a mixture, two or more AOs may be randomly added or block-added. As AO, from the viewpoint of the mechanical properties of rigid polyurethane foam, EO, PO or a mixture thereof is preferable, and from the viewpoint of the flame retardancy of rigid polyurethane foam, EO is more preferable.

[0029] <Method for Producing Polyol (A)> The polyol (A) can be produced by a production method including a step of reacting the above-mentioned resol resin with AO (AO addition step). When the resol resin and AO are reacted, AO is added to the part of the active hydrogen (such as the hydrogen atom of the phenolic hydroxyl group) of the resol resin, and the polyol (A) is produced. Before the AO addition step, a step of producing a resol resin may be included. The production method of the resol resin is as described above.

[0030] (AO addition step) The AO addition step can be carried out by a known method. For example, a method of charging a resol resin, an alkali catalyst, etc. into a pressure-resistant reaction vessel equipped with a stirring device, setting an arbitrary reaction temperature under pressurized conditions, and introducing AO can be mentioned.

[0031] Examples of the alkali catalyst used in the AO addition step include potassium hydroxide, sodium hydroxide, cesium hydroxide, potassium carbonate, triethylenediamine, etc. These alkali catalysts may be used alone or in combination of two or more. The amount of the alkali catalyst used can be, for example, 0.01 to 1 part by mass with respect to 100 parts by mass of the resol resin.

[0032] The pressure during the reaction is preferably 0 to 0.4 MPa (gauge pressure), more preferably 0.1 to 0.3 MPa. The reaction temperature is preferably 80 to 180°C, more preferably 100 to 160°C. The reaction time can be, for example, 0.5 to 12 hours, further 1 to 8 hours. After reacting the resol resin and AO, if necessary, treatments such as neutralization, adsorption of the catalyst, filtration, dehydration, etc. may be carried out.

[0033] In the case of the polyol (A) described above, since a resol resin having 0.25 or less methylol groups per phenol skeleton is used as a starting material, compared with other polyols (for example, a polyether polyol or an aromatic polyester polyol using a novolak type phenol resin as a starting material), the resulting rigid polyurethane foam is excellent in flame retardancy. For example, when a combustion test of a rigid polyurethane foam is conducted, the mass retention rate tends to be high. Therefore, the polyol (A) is suitably used for the production of a rigid polyurethane foam.

[0034] 〔Composition for Rigid Polyurethane Foam〕 The composition for a rigid polyurethane foam according to one aspect of the present invention (hereinafter also referred to as "this composition") contains a polyol component, a catalyst, and a foaming agent. This composition may further contain a foam stabilizer, if necessary. This composition may further contain a flame retardant, if necessary. This composition may further contain other additives other than those described above, if necessary. It should be noted that this composition does not contain the polyisocyanate component described later.

[0035] <Polyol Component> The polyol component is composed of one or more polyols and contains at least polyol (A). The polyol (A) contained in the polyol component may be one kind or two or more kinds. The polyol component may further contain other polyols other than polyol (A), if necessary.

[0036] The ratio of polyol (A) to the total mass of the polyol component is preferably 20 to 100% by mass, more preferably 30 to 100% by mass, and even more preferably 50 to 100% by mass. If the ratio of polyol (A) is at least the above lower limit value, the flame retardancy of the rigid polyurethane foam is more excellent.

[0037] Examples of other polyols include polyhydric alcohols, polyether polyols, and polyester polyols. Examples of polyhydric alcohols include dihydric alcohols having 2 to 20 carbon atoms [aliphatic diols (ethylene glycol, propylene glycol, 1,3- or 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, etc.), alicyclic-containing diols (cyclohexanediol, cyclohexanedimethanol, etc.)]; trihydric alcohols having 3 to 20 carbon atoms [aliphatic triols (glycerin, trimethylolpropane, trimethylolethane, hexanetriol, etc.), etc.]; polyhydric alcohols having 4 to 8 or more valences and 5 to 20 carbon atoms [aliphatic polyols (pentaerythritol, sorbitol, mannitol, etc.), intramolecular dehydration products of aliphatic polyols (sorbitan, etc.), intermolecular dehydration products of aliphatic polyols (diglycerin, dipentaerythritol, etc.); and saccharides and their derivatives (sucrose, glucose, mannose, fructose, methyl glucoside, etc.), etc. Examples of polyether polyols include adducts of AO to active hydrogen-containing compounds (the above polyhydric alcohols, polyhydric phenols, ammonia, amines, carboxylic acids, phosphoric acid, etc.) and mixtures thereof. Examples of AO are the same as those described above, and preferred embodiments are also the same. Examples of polyester polyols include condensation reaction products of the above polyhydric alcohols and / or the above polyether polyols with polycarboxylic acids, reaction products of the above polyhydric alcohols and / or the above polyether polyols with carboxylic anhydrides, and AO adducts thereof. These polyols may be used alone or in combination of two or more.

[0038] The content of the polyol component is preferably 10 to 80% by mass, more preferably 30 to 70% by mass, based on 100% by mass of the composition.

[0039] <Catalyst> As the catalyst, known catalysts used in the production of rigid polyurethane foam can be used, for example, isocyanuration catalysts (hereinafter, also simply referred to as "nuration catalysts"), urethanization catalysts. Examples of the nuration catalyst include potassium octylate, quaternary ammonium salts and the like. Examples of the urethanization catalyst include tertiary amine catalysts such as triethylenediamine, N-ethylmorpholine, diethylethanolamine, N,N,N',N'-tetramethylhexamethylenediamine, tetramethylethylenediamine, pentamethyldiethylenetriamine, diaminobicyclooctane, 1,2-dimethylimidazole, 1-methylimidazole, 1-isobutyl-2-methylimidazole, bis(dimethylaminoethyl) ether and 1,8-diazabicyclo-[5,4,0]-undecene-7; metal catalysts such as stannous octylate, dibutyltin dilaurate, lead octylate and the like. These catalysts may be used alone or in combination of two or more.

[0040] The content of the nuration catalyst is preferably 0 to 20% by mass, more preferably 1 to 10% by mass, based on 100% by mass of the polyol component. The content of the urethanization catalyst is preferably 0.05 to 10% by mass, more preferably 0.1 to 5% by mass, based on 100% by mass of the polyol component.

[0041] <Blowing agent> As the blowing agent, known blowing agents used in the production of rigid polyurethane foam can be used, for example, water, liquefied carbon dioxide gas, hydrogen atom-containing halogenated hydrocarbons, low-boiling hydrocarbons and the like. Specific examples of the hydrogen atom-containing halogenated hydrocarbons include hydrochlorofluorocarbons (HCFC) such as HFC-245fa, HFC-365mfc; hydrofluoroolefins (HFO) such as HFO-1336mzz(Z), HFO-1233zd. Examples of the low-boiling hydrocarbons include hydrocarbons having a boiling point of -5 to 70°C, and specific examples thereof include butane, pentane, cyclopentane. As the foaming agent, water and HFO are preferable from the viewpoints of the thermal conductivity and moldability of the rigid polyurethane foam. These foaming agents may be used alone or in combination of two or more.

[0042] The content of the foaming agent can be appropriately set in consideration of the type of the foaming agent and the density of the rigid polyurethane foam. For example, when water and HFO are used in combination as the foaming agent, the content of water is preferably 0.1 to 10% by mass and the content of HFO is preferably 10 to 100% by mass, more preferably the content of water is 0.5 to 5% by mass and the content of HFO is 20 to 80% by mass with respect to 100% by mass of the polyol component.

[0043] <Cell stabilizer> As the cell stabilizer, known cell stabilizers used in the production of rigid polyurethane foam can be used, and examples thereof include dimethylsiloxane-based cell stabilizers and polyethersiloxane polymer-based cell stabilizers.

[0044] The content of the cell stabilizer is preferably 1 to 10% by mass, more preferably 2 to 5% by mass with respect to 100% by mass of the polyol component.

[0045] <Flame retardant> As the flame retardant, known flame retardants can be used, and examples thereof include phosphate esters, halogenated phosphate esters, aluminum hydroxide, antimony oxide, boron compounds, bromine compounds, chlorinated paraffin, cyclic fatty acids and the like. Among these, phosphate esters and halogenated phosphate esters are preferable from the viewpoint of the flame retardancy of the rigid polyurethane foam. Examples of the phosphate ester include triphenyl phosphate and tricresyl phosphate. Examples of the halogenated phosphate ester include tris(chloropropyl) phosphate and tris(chloroethyl) phosphate. These flame retardants may be used alone or in combination of two or more.

[0046] The content of the flame retardant is preferably 100% by mass or less, more preferably 50% by mass or less, based on 100% by mass of the polyol component. If the content of the flame retardant is below the above upper limit value, the mechanical properties such as the compressive strength of the rigid polyurethane foam are more excellent. The content of the flame retardant is preferably 10% by mass or more, more preferably 15% by mass or more, based on 100% by mass of the polyol component. If the content of the flame retardant is above the above lower limit value, the flame retardancy of the rigid polyurethane foam is more excellent.

[0047] <Other additives> Examples of other additives include colorants (dyes, pigments, etc.), plasticizers (phthalic acid esters, adipic acid esters, etc.), organic fillers (synthetic short fibers, hollow microspheres made of thermoplastic or thermosetting resins, etc.), antioxidants (hindered phenol-based, hindered amine-based, etc.), anti-aging agents (triazole-based, benzophenone-based, etc.), mold release agents (wax-based, metal soap-based, or a mixed system thereof), and the like. These additives may be used alone or in combination of two or more.

[0048] This composition can be produced by mixing a polyol component, a catalyst, a blowing agent, and other components (foam stabilizer, flame retardant, other additives) as required.

[0049] 〔Rigid polyurethane foam〕 The rigid polyurethane foam according to one aspect of the present invention contains a reaction product of a polyol component and a polyisocyanate component. The polyol component is the same as the polyol component in the above-described composition, and the preferred embodiments are also the same.

[0050] <Polyisocyanate component> The polyisocyanate component consists of one or more polyisocyanates. As the polyisocyanate, any compound having two or more isocyanate groups in the molecule may be used, and known ones used in the production of rigid polyurethane foams can be used. For example, aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, araliphatic polyisocyanates, modified products thereof (e.g., modified products containing urethane groups, carbodiimide groups, allophanate groups, urea groups, biuret groups, isocyanurate groups, or oxazolidone groups, etc.) and mixtures of two or more of these may be mentioned.

[0051] Examples of the aromatic polyisocyanate include aromatic diisocyanates having 6 to 16 carbon atoms (excluding the carbon in the NCO group; the same applies to the following isocyanates), aromatic triisocyanates having 6 to 20 carbon atoms, and crude products of these isocyanates. Specific examples include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4'- or 4,4'-diphenylmethane diisocyanate (MDI), polymethylene polyphenylene polyisocyanate (crude MDI), naphthylene-1,5-diisocyanate, triphenylmethane-4,4',4''-triisocyanate, and the like. Examples of the aliphatic polyisocyanate include aliphatic diisocyanates having 6 to 10 carbon atoms. Specific examples include 1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and the like. Examples of the alicyclic polyisocyanate include alicyclic diisocyanates having 6 to 16 carbon atoms. Specific examples include isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, norbornane diisocyanate, and the like. Examples of the araliphatic polyisocyanate include araliphatic diisocyanates having 8 to 12 carbon atoms. Specific examples include xylylene diisocyanate, α,α,α',α'-tetramethylxylylene diisocyanate, and the like. Specific examples of the modified polyisocyanate include urethane-modified MDI, carbodiimide-modified MDI, sucrose-modified TDI, castor oil-modified MDI, and the like.

[0052] From the viewpoint of the mechanical properties of the rigid polyurethane foam, aromatic polyisocyanates are preferred as the polyisocyanate, and at least one selected from the group consisting of 2,4'- or 4,4'-diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate, and their modified products is more preferred. From the viewpoint of the mechanical properties of the rigid polyurethane foam, the total content of 2,4'- or 4,4'-diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate, and their modified products is preferably 40% by mass or more, more preferably 80% by mass or more, based on the total mass of the polyisocyanate component.

[0053] The rigid polyurethane foam of this embodiment can be produced, for example, by a production method including a step (foam forming step) of reacting a polyol component and a polyisocyanate component in the presence of a catalyst and a blowing agent. When reacting the polyol component and the polyisocyanate component, in addition to the catalyst and the blowing agent, one or more of a foam stabilizer, a flame retardant, and other additives may coexist. Examples of the catalyst, blowing agent, foam stabilizer, flame retardant, and other additives are the same as those described above, and their preferred contents are also the same as those described above.

[0054] The foam forming step can be carried out by a known method except using a polyol component containing polyol (A). A specific example of the foam forming step is shown below. First, a polyol component, a catalyst, a blowing agent, and, if necessary, other components (a foam stabilizer, a flame retardant, other additives) are mixed to prepare the present composition. Next, using a polyurethane foaming machine or a stirrer, the present composition and the polyisocyanate component are rapidly mixed, and the obtained mixed solution (foaming stock solution) is poured into a mold and cured for a predetermined time. Then, demolding is carried out to obtain a rigid polyurethane foam. The mold can be either an open mold (free foaming) or a closed mold (mold foaming). Also, curing can be at room temperature or under heating (for example, 30 to 80 °C). Further, either spray foaming or continuous foaming can be used. In the prepolymer method for the urethanization reaction, since the viscosity of the stock solution obtained by mixing each component becomes high, the one-shot method is preferred. In addition, this production method can be applied to both slab foam and molding by the RIM (reaction injection molding) method, and can also be used to obtain rigid polyurethane foam by the mechanical froth method.

[0055] In the foam formation step, the isocyanate index (NCO INDEX) [(equivalent ratio of NCO groups / active hydrogen atom-containing groups) × 100] is preferably 70 or more, more preferably 100 to 800, still more preferably 200 to 700, and particularly preferably 300 to 600, from the viewpoints of the mechanical properties and flame retardant performance of the rigid polyurethane foam.

[0056] The density of the rigid polyurethane foam of this embodiment is preferably 10 to 500 kg / m 3 more preferably 15 to 100 kg / m 3 still more preferably 25 to 70 kg / m 3 even more preferably. The density is measured by the method described in the examples below.

[0057] The compression strength of the rigid polyurethane foam of this embodiment is preferably 8 N / cm 2 or more, more preferably 10 N / cm 2 or more, still more preferably 12 N / cm 2 or more. The compression strength is measured by the method described in the examples below.

[0058] The thermal conductivity of the rigid polyurethane foam of this embodiment is preferably 30 mW / m·K or less, more preferably 27 mW / m·K or less, still more preferably 24 mW / m·K or less. The thermal conductivity is measured by the method described in the examples below.

[0059] The maximum heat release rate of the rigid polyurethane foam of this embodiment, when the combustion test described in the examples below is carried out, is 200 kW / m 2 or less, preferably 150 kW / m 2 or less, more preferably 120 kW / m 2 or less. If the maximum heat release rate is below the above upper limit value, the flame retardancy is more excellent. The maximum heat release rate is determined by the method described in the examples below.

[0060] The combustion residue of the rigid polyurethane foam of this embodiment, when the combustion test described in the examples below is carried out, is preferably 30% or more, more preferably 50% or more, and even more preferably 60% or more. The combustion residue is determined by the method described in the examples below. [Examples]

[0061] The present invention will be described in more detail by way of examples below, but the present invention is not limited to the examples. In the following, "%" indicates "mass%" unless otherwise specified.

[0062] (Production Examples 1 to 3) According to Table 1, phenol, a 50% aqueous formaldehyde solution, and a 48% aqueous potassium hydroxide solution as an alkali catalyst were charged into a reaction vessel equipped with a stirrer, and then reacted at 65°C for 2 hours while stirring and mixing. Next, neutralization was carried out using a 76% aqueous formic acid solution to adjust the pH to 7.2, and then reacted at 110°C and 150°C for 1 hour each. Thereafter, water and phenol were distilled off under reduced pressure. Thereby, resol resins (resols (1) to (3)) were obtained. In Table 1, the catalyst amounts in Production Examples 1 to 3 are the masses of the 48% aqueous potassium hydroxide solution.

[0063] (Production Examples 4, 5) Resol resins (resols (4), (5)) were obtained in the same manner as in Production Examples 1 to 3 except that triethylamine was used instead of the 48% aqueous potassium hydroxide solution.

[0064] (Comparative Production Example 1) After adjusting the pH to 7.2, a resol resin (resol (6)) was obtained in the same manner as in Production Examples 1 to 3, except that the reaction was not carried out at 110 °C and 150 °C, and water and phenol were distilled off under reduced pressure.

[0065] The physical properties (free phenol content, viscosity, methylol group content, water content) of the resol resins of each example are shown in Table 1. The measurement methods for each physical property are shown below. Free phenol content: Measured according to the provisions of 5.16 of JIS K6910:2007. Viscosity: Measured at 25 °C using an E-type viscometer. However, for Production Examples 4 and 5, since measurement at 25 °C was impossible, the value at 70 °C was measured. Methylol group content (number of methylol groups per phenol skeleton in the resol resin): Measured from the peak area using an NMR measuring device (ECZ500R 13C measuring mode manufactured by JEOL RESONANCE). Water content: Measured using HIRANUMA AQUACOUNTER AQV-2200 (Karl Fischer solution: Honeywell HYDRANAL TM Composite5).

[0066] [Table 1]

[0067] (Examples 1 to 5, Comparative Example 1) According to Table 2, a resol resin as a starting material and potassium hydroxide as an alkali catalyst were charged into a pressure-resistant reaction vessel equipped with a stirrer, and then, while stirring and mixing, ethylene oxide (EO) was introduced into the pressure-resistant reaction vessel at a temperature of 150 °C under a pressurizing condition of 0.1 to 0.3 MPa (gauge pressure) and added to the resol resin. Thereafter, potassium hydroxide was neutralized with acetic acid, and dehydration was carried out at 100 °C and about -0.1 MPa (gauge pressure) for 1 hour to obtain phenolic resin-based polyether polyols (polyols (1) to (6)).

[0068] (Comparative Example 2) The following aromatic polyester polyol was used as the polyol of Comparative Example 2. Aromatic polyester polyol: Phthalic anhydride-based polyester polyol, number average number of active hydrogen-containing functional groups 2, hydroxyl value 315 mgKOH / g.

[0069] (Evaluation) (Physical properties of polyol) The physical properties (hydroxyl value, viscosity, aromatic ring concentration, heat resistance, mass residue ratio) of the polyols of each example are shown in Table 2. The measurement methods of each physical property are shown below. Hydroxyl value: Measured according to Method B of JIS K 1557-1. Viscosity: Measured at 25 °C using a B-type viscometer. Aromatic ring concentration: For polyols (1) to (6), calculated by the following formula. Aromatic ring concentration (%) of polyol (A) = [(78÷106)×(100 - A)÷100+(78÷94)×A÷100]×(B÷1000)×100 Each term in the formula represents the following. 78 = Molecular weight of benzene, 94 = Molecular weight of phenol, 106 = Molecular weight of phenolic resin, A = Free phenol amount (%) described in Table 1, B = Starting material charged amount (g) described in Table 2. For example, in the case of Example 1, it is as follows. Aromatic ring concentration (%) = [(78÷106)×(100 - 40)÷100+(78÷94)×40÷100]×(681÷1000)×100 ≒ 52.6 For the aromatic concentration of the above aromatic polyester polyol, the nominal value was used.

[0070] Heat resistance: Thermogravimetric analysis (temperature range: 40 to 500 °C, heating rate: 10 °C / min, under air atmosphere) was performed using TG / DTA6200 manufactured by Seiko Instruments Inc., and evaluated according to the following criteria. ◎: Mass residue ratio is 20% or more. ○: The mass residual rate is 10% or more and less than 20%. ×: The mass residual rate is less than 10%. Mass residual rate: The ratio of the sample mass at the time of reaching 500 °C to the sample mass before the start of thermogravimetric analysis.

[0071]

Table 2

[0072] The polyols of Examples 1 to 5 were superior in heat resistance and had a higher mass residual rate compared to the polyol (aromatic polyester polyol) of Comparative Example 2. From this, it can be judged that the rigid polyurethane foam using the polyols of Examples 1 to 5 has higher heat resistance during combustion and is superior in flame retardancy compared to the rigid polyurethane foam using the polyol of Comparative Example 2.

[0073] <Preparation and Evaluation of Rigid Polyurethane Foam> According to Table 3, a polyol and each additive were mixed to obtain a polyol composition. The obtained polyol composition and organic polyisocyanate (crude MDI, "MR-200" manufactured by Tosoh Corporation, NCO% = 31.5) were each adjusted to a temperature of 20 °C and then mixed, and stirred at 8000 revolutions per minute for 7 seconds using a hand mixer. The obtained mixture was poured into a mold (aluminum, length × width × height = 300 mm × 300 mm × 50 mm) adjusted to a temperature of 60 °C, and demolded after 5 minutes to obtain a rigid polyurethane foam.

[0074]

Table 3

[0075] In Table 3, the following additives were used. Flame retardant: Tris(chloropropyl) phosphate (TMCPP manufactured by Daihachi Chemical Industry Co., Ltd.). Catalyst a: Urethane-forming catalyst (Dabco 33LV manufactured by Evonik Japan Co., Ltd.). Catalyst b: Catalyst for forming nurate (Dabco K-15 manufactured by Evonik Japan Co., Ltd.). Catalyst c: Nureation catalyst (Dabco TMR-7 manufactured by Evonik Japan Co., Ltd.). Foaming agent: Polyether siloxane polymer (SH-193 manufactured by Dow Corning Toray Co., Ltd.). Blowing agent a: Water. Blowing agent b: HFO-1233zd (Solstice LBA manufactured by Honeywell).

[0076] Table 4 shows the mechanical properties (density, compressive strength, thermal conductivity) of the obtained rigid polyurethane foam. However, for Comparative Example 1, since the foam had poor swelling and no sample suitable for measuring physical properties could be obtained, it was designated as "foaming impossible" and the mechanical properties were not measured. The measurement methods for each physical property are shown below. Density: A sample piece of 200×200×40 mm was cut out from the obtained rigid polyurethane foam, and the density was calculated by dividing the mass of the sample piece by the volume. Compressive strength: According to JIS K7220, a sample piece of 50×50×35 mm was cut out from the obtained rigid polyurethane foam. The sample piece was compressed by 10% with respect to the thickness and the compressive stress was measured. Then, the value obtained by dividing the compressive stress by the cross-sectional area was taken as the compressive strength. Thermal conductivity: According to JIS A1412-2, a sample piece of 200×200×40 mm was cut out from the obtained rigid polyurethane foam. Then, the thermal conductivity was measured using a thermal conductivity measuring machine "AUTO-Λ HC-074" manufactured by Eihong Seiki Co., Ltd.

[0077] Also, a sample piece of 99×99×40 mm was cut out from the central part of the obtained rigid polyurethane foam. A combustion test was conducted using a "cone calorimeter C3" manufactured by Toyo Seiki Seisakusho Co., Ltd. in accordance with ISO5660, and the maximum heat release rate and combustion residue were determined. The results are shown in Table 4.

[0078]

Table 4

[0079] According to the polyols of Examples 1 to 5, rigid polyurethane foams could be produced without problems. The obtained rigid polyurethane foams had a slower maximum heat release rate in the combustion test and more combustion residues compared to the rigid polyurethane foams using the polyol of Comparative Example 2, and were excellent in flame retardancy. Also, the mechanical properties were good.

Claims

1. An alkylene oxide adduct of a resol type phenol resin, wherein the number of methylol groups per phenol skeleton in the resol type phenol resin is 0.25 or less, and having a viscosity at 25 ° C of 1,000 to 35,000 mPa·s, a polyether polyol.

2. The polyether polyol according to claim 1, wherein the resol type phenol resin contains 5 to 50% by mass of free phenols based on the total mass of the resol type phenol resin.

3. The polyether polyol according to claim 1 or 2, wherein the resol type phenol resin contains 0 to 0.3% by mass of water based on the total mass of the resol type phenol resin.

4. An alkylene oxide adduct of a resol type phenol resin, wherein the number of methylol groups per phenol skeleton in the resol type phenol resin is 0.25 or less, and having a hydroxyl value of 200 to 400 mgKOH / g, a polyether polyol.

5. The polyether polyol according to any one of claims 1 to 3, having a hydroxyl value of 200 to 400 mgKOH / g.

6. The polyether polyol according to any one of claims 1 to 5, wherein the alkylene oxide is ethylene oxide, propylene oxide or a mixture thereof.

7. A method for producing a polyether polyol according to any one of claims 1 to 6, comprising a step of reacting the resol type phenol resin with the alkylene oxide, a method for producing a polyether polyol.

8. Before the step of reacting the resol type phenol resin with the alkylene oxide, it includes a step of producing the resol type phenol resin, In the step of producing the resol type phenol resin, phenols and aldehydes are reacted in the presence of an alkali catalyst, the resulting reaction product is neutralized to a pH of 7.0 to 9.0, and the resulting neutralized product is subjected to a methylol group reduction treatment, the production method according to claim 7.

9. Comprising a polyol component, a catalyst, and a foaming agent, wherein the polyol component includes a polyether polyol which is an alkylene oxide adduct of a resol type phenol resin, and the number of methylol groups per phenol skeleton in the resol type phenol resin is 0.25 or less, a composition for rigid polyurethane foam.

10. A composition for rigid polyurethane foam, comprising a polyol component, a catalyst, and a blowing agent, wherein the polyol component contains the polyether polyol according to any one of Claims 1 to 6.

11. A rigid polyurethane foam, comprising a reaction product of a polyol component and a polyisocyanate component, wherein the polyol component contains a polyether polyol which is an alkylene oxide adduct of a resol-type phenol resin, and the number of methylol groups per phenol skeleton in the resol-type phenol resin is 0.25 or less.

12. A rigid polyurethane foam, comprising a reaction product of a polyol component and a polyisocyanate component, wherein the polyol component contains the polyether polyol according to any one of Claims 1 to 6.

13. A method for producing a rigid polyurethane foam, comprising a step of reacting a polyol component and a polyisocyanate component in the presence of a catalyst and a blowing agent, wherein the polyol component contains a polyether polyol which is an alkylene oxide adduct of a resol-type phenol resin, and the number of methylol groups per phenol skeleton in the resol-type phenol resin is 0.25 or less.

14. A method for producing a rigid polyurethane foam, comprising a step of reacting a polyol component and a polyisocyanate component in the presence of a catalyst and a blowing agent, wherein the polyol component contains the polyether polyol according to any one of Claims 1 to 6.

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