JP2012153828A - Polyurethane foam, and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyurethane foam excellent in flame retardancy.SOLUTION: This polyurethane foam is produced from raw materials including at least polyisocyanate, polyol, a foaming agent, a catalyst and a surfactant, where an ester composition, obtained by adding an alkylene oxide to a carboxy group of a ring-opening reaction product of a halogenated carboxylic anhydride mediated by an alcohol, is used as a part of the polyol. In a preferred embodiment of the invention, the alcohol is an oxyalkylene glycol with a molecular weight of 100-1,000 and/or a polyoxyalkylene glycol with a number-average molecular weight of 100-1,000, and the halogenated carboxylic anhydride is an intramolecular anhydride of a divalent halogenated carboxylic acid.

Description

  The present invention relates to a polyurethane foam having excellent flame retardancy and a method for producing the same.

  In general, polyurethane foams are prepared as a mixed liquid (premix liquid) and a polyisocyanate liquid in which polyols such as polyether polyol and / or polyester polyol, foaming agent, catalyst, surfactant, and flame retardant as necessary are mixed. And they are manufactured by a method of mixing and foaming and curing in a short time. Since polyurethane foam has excellent heat insulation properties, it is widely used in the form of spraying, pouring, boarding, and paneling in cold storage rooms, refrigerators, freezing rooms, freezers, heat insulating materials for general buildings, and the like.

  In addition to the heat insulating property, flame retardancy is mentioned as a physical property required for polyurethane foam, and particularly when used as a heat insulating wall construction member of a general building, high flame retardancy is required. As a method for improving the flame retardancy of a polyurethane foam, isocyanurate modification in which an isocyanate is trimerized using a potassium-based or quaternary ammonium salt-based catalyst is generally performed. However, although isocyanurate modification is effective in improving flame retardancy, when it is introduced in a large amount, the so-called liquid ratio of the premix liquid and the polyisocyanate liquid is out of the practical range, or the resulting polyurethane foam is brittle. And the problem that adhesiveness deteriorates arises.

  As another method, a method using a large amount of a phosphate ester flame retardant such as trismonochloropropyl phosphate has been proposed. However, when a large amount of a phosphoric ester-based flame retardant is used, it itself has no reaction point and acts as a plasticizer, so that there is a problem that the strength of the resulting polyurethane foam is reduced (Patent Document 1).

  As a polyol for improving the flame retardancy of polyurethane foam, a chlorendic acid type polyol, which is one kind of chlorinated carboxylic acid, is sometimes used, and an esterification reaction between chlorendic acid and a polyhydric alcohol such as diethylene glycol is performed. And polyester polyol (Patent Document 2) obtained by dissolving chlorendic acid in a polyhydric alcohol such as propylene glycol and then adding 2 mol or more of alkylene oxide (Patent Document 3). It is done.

  However, in the production of such polyols, the esterification reaction takes a long time, and depending on the reaction conditions, side reactions of dechlorination and dehydrochlorination occur, resulting in equipment corrosion and a decrease in chlorine concentration in the product. In addition, when adding alkylene oxide, there is a problem that a neutralization or removal step of sodium hydroxide, potassium hydroxide or the like usually used as a catalyst is necessary. But it is not practical.

JP 2009-149760 A JP-A-6-172480 Japanese Patent Laid-Open No. 11-228803

  Accordingly, an object of the present invention is to provide a practical method for producing a polyurethane foam having high flame retardancy.

  That is, the first gist of the present invention is a polyurethane foam using at least a polyisocyanate, a polyol, a foaming agent, a catalyst, and a surfactant as a raw material, and a halogenated carboxylic acid anhydride derived from an alcohol as a part of the polyol. A polyurethane foam characterized by using an ester composition obtained by adding an alkylene oxide to a carboxyl group of a ring-opening reaction product.

  The second gist of the present invention is a process for producing a polyurethane foam using polyisocyanate, polyol, foaming agent, catalyst, and surfactant as raw materials, and a halogenated carboxylic acid anhydride by alcohol is used as part of the polyol. The present invention resides in a method for producing a polyurethane foam, characterized by using an ester composition obtained by adding an alkylene oxide to a carboxyl group of a product ring-opening reaction product.

  According to the present invention, the above-described problems can be solved.

  Hereinafter, the present invention will be described in detail.

  The polyurethane foam of the present invention is a polyurethane foam using at least a polyisocyanate, a polyol, a foaming agent, a catalyst, and a surfactant as a raw material, and a ring-opening reaction of a halogenated carboxylic acid anhydride with an alcohol as a part of the polyol. An ester composition obtained by adding alkylene oxide to the carboxyl group of the product is used.

  The ester composition is obtained by a first step in which a halogenated carboxylic acid anhydride is subjected to a ring-opening reaction with an alcohol, and a second step in which an alkylene oxide is added to the carboxyl group of the ring-opening reaction product.

  As the halogenated carboxylic acid anhydride, an intramolecular anhydride of a halogenated divalent carboxylic acid is preferable. In addition to chlorendic anhydride, mono-, di-, tri- and tetra-chlorophthalic anhydride, bromophthalic anhydride, etc. And halogenated phthalic anhydrides. Among these, chlorendic anhydride and tetrachlorophthalic anhydride are preferable, and chlorendic anhydride is most preferable. Two or more of these halogenated carboxylic acid anhydrides may be used in combination. Note that chlorendic anhydride refers to hexachloroendomethylenetetrahydrophthalic anhydride.

  Examples of the alcohol used for the ring-opening reaction include monovalent or polyhydric alcohols. Examples of monohydric alcohols include aliphatic monohydric alcohols such as methanol, ethanol, propanol, butanol, octanol and lauryl alcohol, aromatic monohydric alcohols such as benzyl alcohol and phenol, ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, A monohydric alcohol containing an ether bond such as phenoxyethanol can be mentioned.

  Polyhydric alcohols include aliphatic dihydric alcohols such as ethylene glycol, propanediol, and butanediol, oxyalkylene glycols such as diethylene glycol, triethylene glycol, and dipropylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. And polyoxyalkylene glycol. In addition, trihydric or higher alcohols such as glycerin and trimethylolpropane may be used. Among them, oxyalkylene glycol or polyoxyalkylene glycol is preferable, and oxyalkylene glycol having a molecular weight of 100 to 1000 or polyoxyalkylene glycol having a number average molecular weight of 100 to 1000 is most preferable. Two or more of these monohydric alcohols and polyhydric alcohols may be used in combination.

  In the ring-opening reaction, the molar ratio of alcohol to halogenated carboxylic acid anhydride is 0.5 to 15.0. If it is less than 0.5, unreacted halogenated carboxylic acid anhydride remains, and if it exceeds 15.0, the halogen concentration of the ester composition decreases and flame retardancy decreases, A lot of reaction alcohol remains. The molar ratio of alcohol to halogenated carboxylic acid anhydride is preferably 0.55 to 14.0, more preferably 0.6 to 13.0.

  In the first step for producing the ester composition, the halogenated carboxylic acid anhydride is subjected to a ring-opening reaction with an alcohol. In this case, it is preferable to carry out the reaction without using a catalyst. This is because when an esterification catalyst used in a normal esterification reaction is used, it is difficult to stop the reaction only by the ring-opening reaction of the halogenated carboxylic acid anhydride. Even if the esterification reaction further proceeds after the ring-opening reaction, the flame retardancy of the ester composition of the present invention is not significantly impaired, but the viscosity may increase and a handling problem may occur.

  The reaction product of the first step is a ring-opening reaction product of halogenated carboxylic acid anhydride with alcohol. The ring-opening reaction product here is a product represented by the AB type or the ABA type, assuming that the divalent halogenated carboxylic acid anhydride is A and the divalent alcohol is B. Say. For example, when tetrachlorophthalic anhydride and diethylene glycol are used as raw materials, they indicate those represented by the following structural formulas: A-B type is hydroxycarboxylic acid, A-B-A type is dicarboxylic acid and Become. When only a monohydric alcohol is used, if the monohydric alcohol is B, only the AB type is a ring-opening reaction product.

  In addition to the above ring-opening reaction product, the reaction product of the first step is a diester compound in which two carboxyl groups of an unreacted halogenated carboxylic acid anhydride, alcohol, and halogenated carboxylic acid anhydride react with the alcohol. Furthermore, it becomes a mixture of oligomeric ester compounds and the like that have undergone further reaction. These approximate composition ratios (molecular weight distribution) can be analyzed by gel permeation chromatography (GPC) or the like. The content of the ring-opening reaction product in the mixture is usually 20% by weight or more, preferably 25% by weight or more, more preferably 30% by weight as the total amount of AB type and / or ABA type. That's it. Although it may be less than 20% by weight, flame retardancy may be reduced when the halogen concentration is lowered due to an increase in the amount of unreacted alcohol. In addition, when there are many more oligomeric ester compounds that have undergone further reaction, the viscosity may increase and handling may be difficult.

  The reaction temperature in the first step is usually in the range of 80 to 200 ° C, preferably 100 to 170 ° C. Since the reaction is stopped only by the ring-opening reaction of the halogenated carboxylic acid anhydride, it is important not to raise the temperature excessively. For example, when tetrachlorophthalic anhydride is used as a raw material, the temperature may rise to about 160 ° C due to the heat generated by ring-opening esterification of tetrachlorophthalic anhydride at about 120-140 ° C. Heat is required.

  On the other hand, the reaction pressure is usually a slight reduced pressure of about -10 kPa, preferably a normal pressure, and in some cases, a slightly increased pressure of about +10 kPa. In order not to distill off the raw material alcohol, it is important not to raise the degree of vacuum too much. For example, when a low-boiling alcohol such as butanol is used, it is necessary to pay more attention to temperature and pressure in order to stop the reaction only by the ring-opening reaction. Of course, depending on the type of raw material used, the target acid value, and the molecular weight distribution, the temperature and pressure may exceed the above ranges.

  The reaction time is usually about 10 to 60 minutes. If the reaction is carried out for too long, the esterification reaction or oligomerization reaction may further proceed. The reaction end point is when the reaction solution becomes uniform and the acid value reaches a predetermined value obtained from the feed ratio of the raw materials by sampling. Distillation of by-product water accompanying the esterification reaction is a measure of the progress of esterification and oligomerization reactions other than the ring-opening reaction, but if the esterification or oligomerization reaction proceeds too much, Moisture may be increased, and the second step may be adversely affected. For this purpose, it is advisable to remove the water in the system by reducing the pressure at the end of the reaction. It is also possible to partially distill off the unreacted alcohol under reduced pressure.

  At the start of the reaction, it is preferable to replace the space of the reaction vessel with nitrogen in order to prevent coloring of the product, and to further remove dissolved oxygen in the reaction solution. Moreover, the reaction mode can be applied to normal batch equipment or continuous equipment, but the batch reaction is preferable because the viscosity of the resulting product may be considerably higher than the alcohol component used as a raw material. .

  In the second step, alkylene oxide is added to the carboxyl group newly generated by ring-opening reaction of the halogenated carboxylic acid anhydride with alcohol in the first step. The alkylene oxide to be added is usually 1 mole per mole of carboxyl group, but 2 moles or more of alkylene oxide may be added. In this case, the reaction is preferably carried out without a catalyst. When a catalyst used in the usual addition reaction of alkylene oxide is used, 2 mol or more of alkylene oxide is added per 1 mol of carboxyl group, unreacted alcohol, In many cases, alkylene oxide is added to the hydroxyl group produced in the first step, the hydroxyl group produced after addition of alkylene oxide in the second step, and the like. This does not significantly impair the flame retardancy of the ester composition of the present invention, but lowering the halogen concentration is not preferable because it leads to a decrease in flame retardancy. Further, when the added catalyst remains in the ester composition, for example, it may be adversely affected when used in the urethanization reaction. Therefore, it is preferable to perform post-treatment such as neutralization, filtration, and adsorption.

  Examples of the alkylene oxide include ethylene oxide, propylene oxide, and butylene oxide. Among these, ethylene oxide and propylene oxide are preferably used. Two or more of these may be used in combination.

  The reaction product of the second step is usually 1 mole of alkylene oxide per mole of carboxyl group based on the carboxyl group newly formed by ring-opening reaction of the halogenated carboxylic acid anhydride with alcohol in the first step. Is an ester composition to which is added. When the alkylene oxide is C, the C-A-B type and the C-A-B-A-C type for the ring-opening reaction product represented by the A-B type or the A-B-A type described above The one represented by For example, when tetrachlorophthalic anhydride, diethylene glycol, or ethylene oxide is used as a raw material, it refers to those represented by the following structural formula, and both C-A-B and C-A-B-A-C types are diols. Become a mold. When only a monohydric alcohol is used, if the monohydric alcohol is B, only the C-A-B type is the ester composition.

  The reaction product of the second step includes, in addition to the above ester composition, a product in which alkylene oxide is further added, an unreacted halogenated carboxylic acid anhydride, alcohol, and halogenated carboxylic acid anhydride from the first step. It becomes a mixture of a diester compound in which two carboxyl groups and alcohol react, an oligomeric ester compound that has further undergone a reaction, a product in which alkylene oxide is added to them, and an alkylene glycol that is produced by the reaction of alkylene oxide with water. . These approximate composition ratios (molecular weight distribution) can be analyzed by gel permeation chromatography (GPC) or the like. The content of C-A-B type and / or C-A-B-A-C type in the ester composition of the present invention is usually 20% by weight or more, preferably 25% by weight or more, more preferably 30% by weight. % Or more. Although it may be smaller than 20% by weight, flame retardancy may be lowered when the halogen concentration is lowered due to an increase in unreacted alcohol or the like. In addition, when there are many more oligomeric ester compounds that have undergone further reaction, the viscosity may increase and handling may be difficult.

  When alcohol having a molecular weight distribution such as polyethylene glycol is used, or when alkylene oxide is added in 2 mol or more to a carboxyl group, unreacted alcohol or hydroxyl group formed in the first step, When alkylene oxide is further added to a hydroxyl group or the like generated after addition of alkylene oxide, it is difficult to analyze the approximate composition ratio (molecular weight distribution) of these reaction products by gel permeation chromatography (GPC) or the like. In that case, by comparing the hydroxyl value of the product calculated from the raw materials with the hydroxyl value obtained by actually analyzing the product, it can be a measure of whether the reaction has proceeded as expected. For example, when the actual value of the hydroxyl value of the product is lower than the hydroxyl value of the product calculated from the raw materials, it is considered that a large amount of alkylene oxide is added in some form.

  The necessary amount of alkylene oxide in the second step is 1 mole per mole of carboxyl group, but it is preferably used in excess in order to efficiently proceed the addition reaction. The excess amount of alkylene oxide is usually 0.3 to 10 mol, preferably 0.5 to 7 mol, more preferably 1 to 5 mol, per mol of carboxyl group. When alkylene oxide is used in excess, the remaining alkylene oxide is distilled off under reduced pressure after the reaction.

  The reaction temperature in the second step is usually in the range of 50 to 170 ° C, preferably 70 to 150 ° C. When the reaction temperature is less than 50 ° C., the reaction time becomes longer, and when it exceeds 170 ° C., the reaction product is remarkably colored or deteriorated easily. The reaction is easy to control if the reaction is started at about 50 ° C. and the temperature is gradually raised to about 150 ° C. while confirming the reflux of the alkylene oxide and the progress of the reaction.

  On the other hand, the reaction pressure is not particularly limited, and normal pressure or arbitrary pressurizing conditions can be adopted. Since many alkylene oxides have a low boiling point, the reaction is performed at a pressure corresponding to the reaction temperature and the charged amount (charged molar ratio). In addition, the pressure is reduced after the reaction, and excess alkylene oxide and water are distilled off.

  At the start of the reaction, it is preferable to replace the space of the reaction vessel with nitrogen in order to prevent coloring of the product, and to further remove dissolved oxygen in the reaction solution. Moreover, although the reaction form can be applied with normal batch equipment or continuous equipment, since the alkylene oxide is used, the batch reaction that is easy to apply to the pressure reaction is more preferable.

  The reaction time in the second step is usually about 1 to 5 hours. The end point of the reaction is judged by sampling the reaction solution and measuring the acid value. The unreacted carboxyl group is usually 5 mgKOH / g or less, preferably 4 mgKOH / g or less, more preferably 3 mgKOH / g or less.

  A new hydroxyl group is generated by the addition reaction of the alkylene oxide in the second step, and the content can be quantified as a hydroxyl value together with the hydroxyl group derived from the alcohol used as a raw material in the first step. The hydroxyl value can be adjusted from a high range to a low range depending on the combination of raw materials, but is usually 10 to 500 mgKOH / g, preferably 20 to 450 mgKOH / g, and more preferably 30 to 400 mgKOH / g. If it is less than 10 mg KOH / g, the viscosity may be high and handling may be difficult. If it exceeds 400 mg KOH / g, the halogen concentration decreases due to an increase in unreacted alcohol, and the resulting polyurethane foam flame retardant Sex is reduced.

  The halogen concentration of the ester composition can be calculated from the raw material charge ratio. In addition, halogen can be quantified by elemental analysis such as titration, gravimetric method and ion chromatography combined with combustion method. In general, the higher the halogen concentration, the higher the flame retardancy, and therefore it is suitable for use as a flame retardant. In the case of chlorine, the halogen concentration is usually 5 to 50% by weight, preferably 6 to 45% by weight, and more preferably 7 to 40% by weight. Moreover, in the case of bromine, it is 5 to 80 weight% normally, Preferably it is 6 to 75 weight%, More preferably, it is 7 to 70 weight%. When the halogen concentration is less than 5%, it is necessary to increase the amount of addition when used as a flame retardant. When the chlorine concentration exceeds 50% by weight or when the bromine concentration exceeds 80% by weight, the viscosity becomes remarkably high. Handling may be difficult.

  In the polyurethane foam of the present invention, the amount of the ester composition used as a part of the polyol is usually 1 to 40% by weight, preferably 2 to 35% by weight, more preferably 3 to 30% by weight as a ratio in the total polyol. %. When the amount is less than 1% by weight, the effect of improving the flame retardancy of the polyurethane foam is small, and when it exceeds 40% by weight, physical properties such as mechanical strength may be adversely affected. Two or more types of ester compositions can be used in combination, but the amounts used are all combined.

  Examples of polyols used other than the ester composition include known polyester polyols, polyether polyols, polymer polyols and the like having a hydroxyl value of 30 to 800 mg KOH / g and a functional group number of 1.1 to 8, and these are Two or more types can be used in combination.

  As the polyester polyol, one or more aromatic or aliphatic carboxylic acids such as benzoic acid, orthophthalic acid, terephthalic acid, isophthalic acid, succinic acid, adipic acid, maleic acid, fumaric acid, trimellitic acid, pyromellitic acid, etc. And octanol, ethylene glycol monomethyl ether, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propanediol, dipropylene glycol, tripropylene glycol, polypropylene glycol, butanediol, pentanediol, hexanediol, glycerin, trimethylolpropane, Polyester polyols, butyrolactones, caps obtained by esterification reaction with one or more monohydric to tetrahydric alcohols such as pentaerythritol Polyester polyols obtained by ring-opening polymerization of lactones, and the like. The hydroxyl value of the polyester polyol is usually 30 to 500 mgKOH / g, preferably 35 to 450 mgKOH / g, more preferably 40 to 400 mgKOH / g, and the number of functional groups is usually 1.1 to 3.0, preferably 1.2 to 2.8, more preferably 1.5 to 2.5.

  Among the above polyester polyols, from the viewpoint of improving the flame retardancy of the polyurethane foam, it is preferable to use a polyester polyol made from at least one selected from the group of orthophthalic acid, terephthalic acid and isophthalic acid as the carboxylic acid. . Among these, terephthalic acid and / or isophthalic acid are preferable. The ratio of orthophthalic acid, terephthalic acid and isophthalic acid in the raw carboxylic acid (the ratio of the total when two or more are used) is usually 5 to 100 mol%, preferably 10 to 95 mol%, more preferably 15 to 90 mol%.

  Moreover, in order to improve the brittleness and adhesiveness of a polyurethane foam, aliphatic polyvalent carboxylic acid can be used as carboxylic acid used as the raw material of polyester polyol, and it is particularly preferable to use succinic acid and / or adipic acid. The proportion of the aliphatic polyvalent carboxylic acid in the raw carboxylic acid (the total proportion when used in combination) is usually 1 to 95 mol%, preferably 5 to 75 mol%, more preferably 10 to 70. Mol%.

  The content of the polyester polyol in the total polyol is usually 10 to 90% by weight, preferably 15 to 85% by weight, and more preferably 20 to 80% by weight.

  Polyether polyols are polymers obtained from one or more of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, etc .; alcohols such as ethylene glycol, propanediol, glycerin, trimethylolpropane, pentaerythritol, erythritol, sorbitol, sucrose Adducts of olefins and alkylene oxides; adducts of amines such as ethylenediamine and toluenediamine and the alkylene oxides described above; Mannich-modified polyols; known polyether polyols such as polymer polyols can be used. The hydroxyl value of the polyether polyol is usually 30 to 800 mgKOH / g, preferably 35 to 750 mgKOH / g, more preferably 40 to 700 mgKOH / g, and the number of functional groups is usually 2.0 to 8.0, preferably 2.0. It is -7.5, More preferably, it is 2.0-7.0. Two or more of these polyether polyols can be used in combination.

  In addition to the above polyols, alcohols such as ethylene glycol, diethylene glycol, propanediol, butanediol, and glycerin, alkanolamines such as diethanolamine and triethanolamine, and the like can also be used in combination.

  Examples of the blowing agent include a blowing agent having an ozone depletion coefficient of 0, for example, water; HFC blowing agents such as “HFC-245fa” and “HFC-365mfc”; HC blowing agents such as pentane and cyclopentane; “HFO— And HFO foaming agents such as “1234ze” and “HFO-1234yf”. Water acts as a blowing agent by generating carbon dioxide by reaction with polyisocyanate. In consideration of the environment, it is preferable to use only water among these foaming agents. The blending amount of the foaming agent is appropriately selected depending on the density of the target polyurethane foam, but when only water is used, it is usually 1 to 30 parts by weight, preferably 1.5 to 100 parts by weight with respect to 100 parts by weight of polyol. 27 parts by weight, more preferably 2 to 25 parts by weight. When the amount is less than 1 part by weight, the density of the resulting polyurethane foam becomes too high to be practical, and when it exceeds 30 parts by weight, physical properties such as dimensional stability deteriorate.

  As a catalyst, the well-known catalyst used for manufacture of a normal polyurethane foam can be used. For example, in addition to amine-based catalysts such as triethylenediamine and N, N-tetramethylhexanediamine, quaternary ammonium salt systems; potassium systems such as potassium octylate; tin systems such as dibutyltin dilaurate and tin octylate; octylic acid Examples thereof include lead-based metal catalysts such as lead. The compounding amount of the catalyst is appropriately selected depending on the reactivity and physical properties of the target polyurethane foam, but it is general to combine a foaming catalyst, a resinification catalyst, a balance type catalyst, a trimerization catalyst and the like.

  The surfactant may be any of nonionic, anionic and cationic, but is preferably a nonionic surfactant, and particularly preferably a silicone surfactant. The amount of these surfactants to be used is usually 0.5 to 10 parts by weight as a ratio with respect to 100 parts by weight of the polyol, and two or more kinds of surfactants may be used.

  Depending on the application, various compounds can be used as additives and auxiliaries. For example, a flame retardant and a viscosity reducer are mentioned as a typical additive. For example, chloroalkyl phosphates such as tris (beta chloroethyl) phosphate, tris (beta chloropropyl) phosphate, etc. are usually used as a flame retardant, and propylene carbonate, ethylene carbonate, tetraglyme are used as a thickener. Etc. are used. Additives and auxiliaries other than those described above are not particularly limited, and can be used as long as they are used for the purpose of improving physical properties and operability in ordinary resins as long as they do not have a significant adverse effect. can do.

  The polyisocyanate is not particularly limited as long as it is a compound having two or more isocyanate groups in one molecule. Examples thereof include aliphatic, alicyclic, aromatic polyisocyanates, and modified products thereof. Specific examples of the aliphatic and alicyclic polyisocyanates include hexamethylene diisocyanate and isophorone diisocyanate. Examples of the aromatic polyisocyanate include tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylene polymethylene polyisocyanate and the like, and these carbodiimide modified products and prepolymers can also be used.

  A preferred polyisocyanate in the present invention is an aromatic polyisocyanate or a modified product thereof, and particularly preferred are diphenylmethane diisocyanate, polyphenylene polymethylene polyisocyanate, tolylene diisocyanate, and modified products thereof. Two or more of these may be used in combination. As the polyphenylene polymethylene polyisocyanate, those having an isocyanate group content of usually 25 to 35% by weight and a viscosity of usually 500 mPa · s (25 ° C.) or less are preferably used. Among these modified products, the carbodiimide modified product is a product in which a carbodiimide bond is introduced using a known phosphorus catalyst or the like. The prepolymer is obtained by reacting the above polyisocyanate with a polyol, leaving an isocyanate group at the terminal. In that case, the polyol component used when manufacturing a polyurethane can be used for the polyol component to be used.

  Practically, as a polyisocyanate liquid, in addition to polyisocyanate, additives and auxiliaries may be mixed with polyisocyanate and used depending on applications. For example, for the purpose of improving the mixing property with the aforementioned polyurethane foam composition, a surfactant used also in the polyurethane foam composition may be used in combination as a compatibilizing agent. In this case, a nonionic surfactant is preferable, and a silicone surfactant is particularly preferable. In addition, the aforementioned flame retardant may be used in combination for the purpose of improving flame retardancy and adjusting viscosity.

  In the present invention, the isocyanate index when mixing the polyisocyanate and the polyol is represented by [(number of moles of all isocyanate groups) / (number of moles of all active hydrogen groups excluding water) × 100], usually 50 to 500. , Preferably 60 to 470, more preferably 70 to 450. When the isocyanate index is less than 50, the obtained polyurethane foam may not have sufficient strength, and when it exceeds 500, the resulting polyurethane foam tends to be brittle and the adhesive strength tends to decrease. When water is used as the blowing agent, it is necessary to add polyisocyanate consumed by water separately. In that case, the isocyanate index [(number of moles of isocyanate groups consumed in water) / (water The number of moles of all active hydrogen groups) × 100] is always calculated as 100.

The density of the polyurethane foam of the present invention is usually from 10 to 70 kg / m ³ , preferably from 15 to 65 kg / m ³ , and more preferably from 20 to 60 kg / m ³ when expressed by the free foam core density. When the density is less than 10 kg / m ³ , the obtained rigid polyurethane foam does not have sufficient flame retardancy and mechanical strength, and when it exceeds 70 kg / m ³ , the cost becomes high.

  The polyurethane foam of the present invention can be applied to any of open cells, semi-open cells, and closed cells. In general, high heat insulation performance is required for use as a heat insulating material, and therefore it is preferable that the closed cell ratio is high. On the other hand, in applications where thermal insulation performance is not the highest priority, it is possible to further reduce the density and improve the dimensional stability by making some or all of the bubbles of the polyurethane foam continuous. Examples of the method for making the bubbles continuous include, for example, a method of blending a long-chain polyether polyol obtained by adding propylene oxide to glycerin, a metal salt of a monocarboxylic acid such as calcium stearate or calcium myristylate, polyethylene, or vinyl acetate. Examples thereof include a method of blending such a thermoplastic resin powder, a method of blending a foam stabilizer for promoting continuation of bubbles, and the like.

  The method for producing the polyurethane foam of the present invention is practically used as a liquid A and / or a liquid B, in which polyisocyanate is liquid A, polyol is liquid B, and water, catalyst, surfactant and other auxiliary agents are preliminarily used. The two liquids are mixed, foamed and cured using an apparatus described later. The foaming agent, catalyst, and surfactant are preferably mixed with the B liquid. However, in some cases, the foaming agent, the catalyst, and the surfactant are mixed with the A liquid, or the respective components are not mixed until just before the urethanization reaction. In some cases, it is handled as a raw material liquid.

  In the method for producing a polyurethane foam of the present invention, any apparatus can be used as long as the liquid A and the liquid B can be mixed uniformly. For example, small mixer, low pressure or high pressure foaming machine for injection foaming, low pressure or high pressure foaming machine for slab foaming, low pressure or high pressure foaming machine for continuous line, spraying work For example, a spray foaming machine can be used. In manufacturing the polyurethane foam, the liquid temperatures of the liquid A and the liquid B are usually adjusted to 20 to 60 ° C.

  The polyurethane foam of the present invention can be provided with an appropriate face material on one side or both sides as necessary. As the face material, for example, paper, wood, gypsum board, resin, aluminum foil, steel plate and the like are used.

  EXAMPLES Hereinafter, specific embodiments of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist.

<Synthesis of ester composition (a)>
Synthesis Examples 1-5:
According to the following method, the ester composition was synthesized and analyzed.

  The raw material of the first step is charged into a glass reactor equipped with a stirrer, a cooling pipe, a thermometer, a pressure gauge, a heating device, etc. with a volume of 300 ml, with the raw material ratio shown in Table 1, and the reactor space is filled with nitrogen gas. After the replacement, heating of the reactor was started at normal pressure. After maintaining the reactor internal temperature at 100 ° C. for 30 minutes, the pressure in the system was reduced to −100 kPa and further maintained for 15 minutes to distill off water and the like in the system. Then, it cooled to about 30 degreeC and returned to the normal pressure with nitrogen. Then, the raw material (propylene oxide) of the 2nd process was added with the syringe with the raw material ratio shown in Table 1, and the heating of the reactor was started again at normal pressure. The reflux of propylene oxide started at about 50 to 60 ° C., and while maintaining the reflux of propylene oxide, the temperature was raised to 120 ° C. over about 1 to 2 hours and held there for 2 hours, and then the pressure was reduced to −100 kPa and further 15 Unreacted propylene oxide and the like were distilled off by maintaining for a minute. Then, it cooled to about 30 degreeC, returned to normal pressure with nitrogen, the reaction product was extracted, and the acid value, the hydroxyl value, the viscosity, and the water | moisture content were analyzed. The respective analysis results are shown in Table 1, and the chlorine concentration is also obtained from the raw material ratio and shown in Table 1. The raw material ratios shown in Table 1 are molar ratios, and the amount charged was determined from each molar ratio so that the amount of product obtained after the second step was about 100 g.

<Analysis method>
(1) Acid value:
Measured according to JIS K1557 ₁₉₇₀ .
(2) Hydroxyl value:
Measured according to JIS K1557 ₁₉₇₀ .
(3) Viscosity:
It measured at 25 degreeC using the rotational viscometer (B type viscometer) based on JISK1557 ₁₉₇₀ .
(4) Moisture:
Measured according to JIS K1557 ₁₉₇₀ .

<Preparation of premix solution>
A premix solution was prepared with the ingredients and blends shown in Table 2. The ester composition was treated as a part of the polyol, and the blending ratio in the table was expressed by weight% when the total polyol was 100% by weight.

  In the composition of Table 2, the raw materials described in Table 3 below were used.

<Creation of polyurethane foam>
A pre-mixed solution described in Table 2 and a polyisocyanate solution are taken in a predetermined amount in a polycup, mixed at high speed with an electric mixer, poured into a mold with steel plate face materials prepared on the upper and lower surfaces, and clamped to form a polyurethane foam steel plate A face material sandwich panel was prepared. Table 4 shows the conditions at that time. The polyisocyanate liquid used was polymeric MDI (“Millionate MR-200” manufactured by Nippon Polyurethane Industry Co., Ltd.), and the isocyanate index was 300.

  The obtained polyurethane foam steel sheet face material sandwich panel was cut into a 99 × 99 mm central portion to create a test piece, and the flame resistance was evaluated by a cone calorie test. The corn calorie test was performed in accordance with ISO 5660-1 (2002), and the test time was 20 minutes (non-combustible). The criteria for determination are as follows, and the results are shown in Table 2.

<Cone calorie test (nonflammable) criteria>
(1) The total calorific value for 20 minutes after the start of heating is 8 MJ / m ² or less.
(2) There should be no cracks or holes penetrating to the back side, which is harmful to fire prevention, for 20 minutes after the start of heating.
(3) For 20 minutes after the start of heating, the maximum heat generation rate should not exceed 200 kW / m ² for 10 seconds or more.

  Further, a panel using a 5 × 5 cm steel sheet surface material was separately prepared on the upper surface, and the adhesive strength between the steel sheet surface material and the polyurethane foam was measured using a tensile tester. The criteria for determination are as follows, and the results are shown in Table 2.

<Adhesion strength criteria>
◎: 200 kPa or more ○: 100 kPa or more, less than 200 kPa ×: less than 100 kPa

  From the above results, the following is mainly clear.

(1) Comparison results of Examples using the ester compositions of Synthesis Examples 1 to 4 and Comparative Example 1 using the ester composition of Synthesis Example 5:
In the case of Examples using the ester compositions of Synthesis Examples 1 to 4, in which a halogenated carboxylic acid anhydride was ring-opened with an alcohol and then an alkylene oxide was added to the carboxyl group of the ring-opening reaction product, In the case of Comparative Example 1 using the ester composition of Synthesis Example 5 synthesized in the same manner with a carboxylic anhydride having no halogen, the flame retardancy is reduced and corn calories are obtained. Fail the test.

(2) Comparison results between Examples using the ester compositions of Synthesis Examples 1 to 4 and Comparative Example 2:
Similarly to the above, in the case of Examples using the ester compositions of Synthesis Examples 1 to 4, high flame retardancy that passes the corn calorie test is obtained, but in the case of Comparative Example 2 in which they were not used, flame retardant The nature decreases and the corn calorie test fails.

(3) Comparison results between Example 2 using polyol 3 and other examples:
In the case of Example 2 in which Polyol 3 containing adipic acid in addition to one or more of ortho, tele, and isophthalic acids as a constituent component of the polyester polyol, the adhesion compared to the other examples that were not used Strength is improved.

Claims (8)

  A polyurethane foam using at least a polyisocyanate, a polyol, a foaming agent, a catalyst, and a surfactant as a raw material. As a part of the polyol, an alkylene is added to a carboxyl group of a ring-opening reaction product of a halogenated carboxylic acid anhydride. A polyurethane foam characterized by using an ester composition obtained by adding an oxide.   The polyurethane foam according to claim 1, wherein the amount of the ester composition used is 1 to 40% by weight of the total polyol.   The alcohol in the ester composition is an oxyalkylene glycol having a molecular weight of 100 to 1000 and / or a polyoxyalkylene glycol having a number average molecular weight of 100 to 1000, and the alkylene oxide is ethylene oxide and / or propylene oxide. Polyurethane foam.     The polyurethane foam according to any one of claims 1 to 3, wherein the ester composition contains a component in which 1 mol of alkylene oxide is added to 1 mol of the carboxyl group of the ring-opening reaction product.   The polyurethane foam according to any one of claims 1 to 4, wherein the halogenated carboxylic acid anhydride in the ester composition is chlorendic anhydride and / or chlorophthalic anhydride.   The polyurethane foam according to claim 1, wherein a polyester polyol is used as the polyol.   The polyurethane foam according to any one of claims 1 to 6, wherein water is used as a foaming agent, and the amount thereof used is 1 to 30 parts by weight with respect to 100 parts by weight of polyol.   A method for producing a polyurethane foam using at least a polyisocyanate, a polyol, a foaming agent, a catalyst, and a surfactant as a raw material, wherein a carboxyl of a ring-opening reaction product of a halogenated carboxylic acid anhydride with an alcohol as a part of the polyol A method for producing a polyurethane foam, comprising using an ester composition obtained by adding an alkylene oxide to a group.