JP5397170B2 - Rigid polyurethane foam composition and method for producing rigid polyurethane foam - Google Patents

Description

  The present invention relates to a composition for rigid polyurethane foam and a method for producing the rigid polyurethane foam.

  Rigid polyurethane foam is widely used in cold storage rooms, refrigerators, freezer rooms, freezers, heat insulating materials for general buildings, heat insulating panels and the like because of its excellent heat insulating properties and flame retardancy. Rigid polyurethane foam is generally prepared as a mixed liquid (composition for rigid polyurethane foam) in which polyisocyanate, polyether polyol and / or polyester polyol, foaming agent, and catalyst or surfactant as necessary are mixed. It is manufactured by mixing them and foaming and curing in a short time.

  In that case, a low boiling nonpolar organic solvent is generally used as the blowing agent. Specifically, in addition to CFC-based blowing agents, chlorofluorocarbons such as HCFC-based blowing agents and HFC-based blowing agents, alternative chlorofluorocarbons, pentane HC-based foaming agents such as cyclopentane are used, but since the destruction of the ozone layer has become a problem, the CFC-based foaming agent, especially CFC-11e, which has been used for a wide range of uses until now, has an ozone depletion coefficient. Small HCFC-based blowing agents, especially HCFC-141b, have been used as alternatives. However, this HCFC-141b is not zero in ozone depletion coefficient, and its use has been restricted since the end of 2003. As an alternative, HFC-based foaming agents, particularly HFC-245fa and HFC-365mfc are used. HC-based foaming agents are also used as useful foaming agents.

  However, many of the above foaming agents are global warming substances, and some are very expensive or flammable. Therefore, from the viewpoint of environmental protection, economic viewpoint, and safety, the amount of use is reduced. Consequently, there is a need for the development of water foaming technology in which these foaming agents are not used at all, and carbon dioxide gas generated by the reaction between water and polyisocyanate is used as the foaming agent.

  In particular, many of the heat insulation panels produced in factories currently use HFC-based foaming agents, and the transition to HC-based foaming agents with flammability is enormous, such as modifications to explosion-proof equipment. The switch to water foaming is gradually progressing because of the expense required.

  However, there are the following major problems in spreading the water foaming technology. That is, compared with conventional foaming formulations using HFC-based foaming agents and HC-based foaming agents, the viscosity of the mixed liquid is increased because the effect of reducing the viscosity of the foaming agent cannot be obtained, and water and polyisocyanate The brittleness of the surface and bottom of the resulting rigid urethane foam deteriorates due to the influence of the increase of urea groups generated by the reaction of the above, and the adhesive strength with the adherend tends to decrease, and the flame retardancy deteriorates. Etc.

  As a method for improving the drawbacks of the lowering of adhesiveness due to the increased viscosity of the liquid mixture and the brittleness of the rigid urethane foam, an auxiliary agent having no hydroxyl group such as dialkyl ether of oxyethylene and / or oxypropylene glycol is used. The method to use (refer patent document 1) and the method (refer patent document 2) which mix | blends the auxiliary agent whose hydroxyl group is 0 or 1 similarly like a phosphate ester type compound and an alkylphenol type compound are proposed. In addition, blending a general-purpose thinning agent such as propylene carbonate is partly implemented. However, in these methods, if the amount added is small, the effect of improving brittleness and adhesive strength is small, and if the amount added is large, the cost is disadvantageous, and the strength, dimensional stability, and flame retardancy of the rigid polyurethane foam are reduced. Adverse effects such as further degradation may occur.

  In addition, a method for producing a highly flame-retardant polyisocyanurate foam by foaming with an isocyanate index of 150 or more with water and a large amount of flame retardant without using almost any polyol has been proposed (Patent Literature). 3). However, the rigid polyurethane foam obtained by this method is very fragile and is not practical in terms of adhesion to the adherend.

JP 2002-363241 A Japanese Patent Laid-Open No. 2000-281741 JP 2009-149760 A

  Accordingly, an object of the present invention is to provide a composition for a rigid polyurethane foam, which is suitable for producing a rigid polyurethane foam excellent in flame retardancy and adhesiveness, using water as a main foaming agent. Another object of the present invention is to provide a method for producing a rigid polyurethane foam excellent in flame retardancy and adhesiveness using water as a main foaming agent.

  As a result of intensive studies to achieve the above object, the present inventor can easily achieve the above object by using water as a main blowing agent and using a specific polyester polyol and a specific catalyst. As a result, the present invention was completed.

That is, the first gist of the present invention is a composition for a rigid polyurethane foam used for mixing with a polyisocyanate to form a rigid polyurethane foam under a condition where the isocyanate index is 200 to 400 , and at least a polyol. A composition for rigid polyurethane foam, comprising a catalyst, water as a blowing agent, a surfactant, and using the polyol and catalyst described below.

(1) Use phthalic acid and / or terephthalic acid as the aromatic carboxylic acid component, succinic acid and / or adipic acid as the aliphatic carboxylic acid component, and diethylene glycol, triethylene glycol, number average molecular weight as 600 or less as the alcohol component A polyol containing 60% by weight or more of a polyester polyol obtained by esterification using at least one selected from the group of polyethylene glycols.

(2) amine (excluding imidazole) based catalyst (a), imidazole-based catalyst (b), Ri formed from a combination of quaternary ammonium-based catalyst (c) and potassium-based catalyst (d), the catalyst (a) ~ (d ) Is 0.01 to 20 parts by weight with respect to 100 parts by weight of polyol, and [(c) + (d)] / (b) is 2 to 40 parts by weight.

  Then, the second gist of the present invention is described in the following, in producing a rigid polyurethane foam by mixing polyisocyanate and polyol in the presence of at least a catalyst, water as a blowing agent, and a surfactant. The present invention resides in a method for producing a rigid polyurethane foam, wherein a polyol and a catalyst are used, and a polyisocyanate and a polyol are mixed under a condition of an isocyanate index of 200 to 400.

(1) Use phthalic acid and / or terephthalic acid as the aromatic carboxylic acid component, succinic acid and / or adipic acid as the aliphatic carboxylic acid component, and diethylene glycol, triethylene glycol, number average molecular weight as 600 or less as the alcohol component A polyol containing 60% by weight or more of a polyester polyol obtained by esterification using at least one selected from the group of polyethylene glycols.

(2) amine (excluding imidazole) based catalyst (a), imidazole-based catalyst (b), Ri formed from a combination of quaternary ammonium-based catalyst (c) and potassium-based catalyst (d), the catalyst (a) ~ (d ) Is 0.01 to 20 parts by weight with respect to 100 parts by weight of polyol, and [(c) + (d)] / (b) is 2 to 40 parts by weight.

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

  Hereinafter, the present invention will be described in detail.

  First, the composition for rigid polyurethane foam of the present invention will be described.

  The composition for a rigid polyurethane foam of the present invention is used for mixing with a polyisocyanate to form a rigid polyurethane foam, and includes at least a polyol, a catalyst, water as a blowing agent, a surfactant, and a specific polyol. And using a catalyst.

  The polyol in the rigid polyurethane foam composition of the present invention uses phthalic acid and / or terephthalic acid as the aromatic carboxylic acid component, succinic acid and / or adipic acid as the aliphatic carboxylic acid component, diethylene glycol as the alcohol component, 60% by weight or more of a polyester polyol obtained by an esterification reaction using at least one selected from the group of triethylene glycol and polyethylene glycol having a number average molecular weight of 600 or less is included. Hereinafter, the above polyester polyol is referred to as “specific polyol”.

  In the specific polyol, the ratio of both when using phthalic acid and / or terephthalic acid is not particularly limited. However, if terephthalic acid is used alone or in a large amount, the flame retardancy of the rigid polyurethane foam can be further increased. As other aromatic carboxylic acid components, aromatic monocarboxylic acids having 7 to 10 carbon atoms such as benzoic acid, aromatic polycarboxylic acids having 8 to 12 carbon atoms such as isophthalic acid and trimellitic acid (but phthalic acid) Acid and terephthalic acid can be used in combination, but considering the cost, viscosity, physical properties of rigid polyurethane foam, etc., the amount used is preferably limited to 10 mol% or less of the total carboxylic acid component. The ratio of these aromatic carboxylic acid components to the total carboxylic acid components is 20 to 90 mol%, preferably 25 to 85 mol%, more preferably 30 to 80 mol%.

  In the specific polyol, the ratio of both when succinic acid and / or adipic acid is used is not particularly limited, but if adipic acid is used alone or in a large amount, the viscosity can be further reduced, and succinic acid is used alone or If more is used, the adhesiveness of the rigid polyurethane foam can be further increased. Other aliphatic carboxylic acid components include aliphatic monocarboxylic acids having 1 to 18 carbon atoms such as acetic acid and 2-ethylhexanoic acid, and aliphatics having 2 to 12 carbon atoms such as glutaric acid, sebacic acid and maleic acid. Polyvalent carboxylic acids (excluding succinic acid and adipic acid) can be used in combination, but the amount used is 10 mol% or less of the total carboxylic acid component in consideration of cost, viscosity, physical properties of rigid polyurethane foam, etc. It is preferable that the The ratio of these aliphatic carboxylic acid components to the total carboxylic acid components is usually 10 to 80 mol%, preferably 15 to 75 mol%, more preferably 20 to 70 mol%.

  Each carboxylic acid component may be an acid anhydride such as phthalic anhydride or a derivative such as an ester compound such as dimethyl terephthalate. The amount used in the case of using an acid anhydride or esterified product shall be calculated in terms of mol% converted to the original carboxylic acid.

  In the specific polyol, the alcohol component is preferably triethylene glycol or polyethylene glycol having a number average molecular weight of 400 or less in consideration of cost, viscosity, physical properties of rigid polyurethane foam, and the like. A mixture of diethylene glycol and polyethylene glycol having a number average molecular weight of 400 is also preferable. In this case, the mixing ratio is usually from 0.05 to 20, preferably from 0.1 to 15, and more preferably from 0.15 to 3, as the molar ratio of polyethylene glycol to 1 mol of diethylene glycol. Other alcohol components other than the above, such as C1-C18 aliphatic or aromatic monoalcohols such as 2-ethylhexanol and phenol, ethylene glycol, 1,4-butanediol, glycerin, pentaerythritol C2-10 aliphatic or aromatic polyhydric alcohol can be used in combination, but in consideration of cost, viscosity, physical properties of rigid polyurethane foam, the amount used is 10 mol% or less of the total alcohol components It is preferable to fasten.

  The hydroxyl value of the specific polyol is usually in the range of 100 to 400 mgKOH / g, preferably 110 to 390 mgKOH / g, and more preferably 120 to 380 mgKOH / g. When the hydroxyl value is less than 100 mgKOH / g, the mechanical strength of the resulting rigid urethane foam may be lowered. On the other hand, when the molecular weight is larger than 400 mgKOH / g, the molecular weight distribution of a large amount of unreacted alcohol is obtained, and the effect of improving brittleness and adhesiveness is reduced. The liquid ratio may exceed the appropriate range.

  The viscosity of the specific polyol at 25 ° C. is usually 5000 mPa · s or less, preferably 4000 mPa · s or less, more preferably 3000 mPa · s or less. When it is higher than 5000 mPa · s, there is a possibility that the handling may be hindered or problems such as the inability to perform spraying may occur during the production of rigid urethane foam.

  The average functional group number of the specific polyol is usually 1.5 to 3.0, preferably 1.7 to 2.5. When the average number of functional groups is less than 1.5, there is a possibility that adverse effects such as a decrease in mechanical strength and dimensional stability of the rigid polyurethane foam may occur. On the other hand, when it is larger than 3.0, the viscosity is increased, which may cause a problem.

  Further, as described above, monovalent alcohols such as methanol, ethanol, isopropanol, and 2-ethylhexanol can be used in combination as a method for reducing the viscosity of the specific polyol. However, when these monohydric alcohols are used, it is important that the hydroxyl value and the number of functional groups are not deviated from the above ranges. That is, when synthesizing the specific polyol, monohydric alcohol may be distilled out of the reaction system to deteriorate the yield of the specific polyol or adversely affect the strength and heat resistance of the polyurethane foam. It is preferable to use a hydric alcohol as long as it does not cause a practical problem.

  The specific polyol can be produced according to a known method using an esterification reaction. The general production conditions are listed below.

  In the esterification reaction, an esterification catalyst is usually used. In general, an acid catalyst is often used as the catalyst. As the Lewis acid, for example, orthotitanate such as tetraisopropyl titanate and tetra-n-butyl titanate, tin compounds such as diethyltin oxide and dibutyltin oxide, and metal compounds such as zinc oxide are used. In addition to the Lewis acid, a Bronsted acid such as p-toluenesulfonic acid may be used.

  Polyol is converted into polyurethane by urethanation reaction with polyisocyanate, but at the same time, reaction between polyisocyanate and water, reaction between polyisocyanates and the like occur. At this time, it is preferable that the catalyst used for the synthesis of the polyol does not affect the reaction behavior of these reactions. Therefore, among the above esterification catalysts, orthotitanate is preferable. Moreover, the usage-amount of an esterification catalyst is 0.01 to 1.0 weight% normally with respect to the sum total of the carboxylic acid component and alcohol component which are used for a raw material, Preferably it is 0.03 to 0.2 weight%. Depending on the use of the polyurethane, the reaction may be carried out without using these esterification catalysts, or a deactivation treatment may be performed after the reaction, or it may be removed by purification or the like.

  The reaction temperature of the esterification reaction is usually 150 to 250 ° C, preferably 180 to 230 ° C. For example, the reaction is easy to control if the reaction is started at 150 ° C. and the temperature is gradually raised to 230 ° C. as the reaction proceeds.

  On the other hand, the reaction pressure may be normal pressure, but it may be gradually reduced with the progress of the reaction in order to remove the by-product water out of the system and complete the reaction quickly. However, when the degree of vacuum during the reaction is insufficient, the degree of completion of the esterification reaction is lowered, and a polyester polyol having a high acid value can be obtained. On the other hand, when the pressure is excessively reduced during the reaction, not only the alcohol component is distilled out of the system and the yield is deteriorated, but also a high molecular weight polyester polyol is formed, the viscosity of the obtained polyester polyol is remarkably increased, and foaming is performed. There may be a tendency to lower the compatibility with the agent. Accordingly, the appropriate ultimate reaction pressure varies depending on the reaction temperature. For example, when the reaction temperature is 200 ° C., it is usually 1 to 50 kPa, preferably 3 to 30 kPa. Depending on the value, the type of alcohol used, and the amount used, the reaction may be carried out under conditions other than the above pressure range. Further, instead of reducing the pressure, a small amount of an organic solvent such as toluene or xylene may be used in combination, and water produced as a by-product may be removed azeotropically outside the system.

  The end point of the reaction is usually determined by the amount of unreacted carboxyl groups of the carboxylic acid used. On the other hand, in the use of rigid polyurethane foam, the presence of an acid often reduces the reactivity of the urethanization reaction with the polyisocyanate component and is not preferable, and may also affect the storage stability of the polyester polyol. is there. Therefore, it is preferable that the amount of unreacted carboxylic acid (that is, acid value) is as low as possible for the specific polyol. The acid value is usually 5 mgKOH / g or less, preferably 3 mgKOH / g or less, more preferably 1 mgKOH / g or less. Furthermore, an acid value of 0.5 mgKOH / g or less may be desired under severe urethanization reaction conditions.

  In addition, in order to maintain the average number of functional groups and the hydroxyl value of the ester compound at a certain target value, it is important that the alcohol component in an equilibrium state is not distilled out of the reaction system as much as possible during the esterification reaction during the esterification reaction. It is. When the alcohol component is distilled too much, the hydroxyl value of the ester compound is decreased, and as a result, the viscosity of the resulting polyester polyol may be significantly increased. Therefore, the amount of the alcohol component distilled out of the system during the esterification reaction is usually 5% or less, preferably 3% or less, more preferably 1% or less, based on the total alcohol components. However, the alcohol component may be distilled out beyond the above range depending on the viscosity and hydroxyl value of the target polyester polyol and the amount of the alcohol component used.

  At the start of the reaction, it is preferable to replace the space in the reaction vessel with nitrogen in order to prevent the resulting polyester polyol from being colored, and to remove dissolved oxygen in the reaction solution. Moreover, after completion | finish of reaction, you may adjust the physical property and performance of polyester polyol by distilling an unreacted alcohol component out of the system on suitable pressure-reduced conditions.

  As the reaction format for producing the specific polyol, normal batch equipment or continuous equipment can be applied, but the reaction time is long, and the viscosity of the resulting polyester polyol is compared with the alcohol component used as a raw material. The batch reaction is preferable because it becomes considerably high.

  In the present invention, in addition to the specific polyol, a polyether polyol or polyester polyol having a hydroxyl value of usually 50 to 800 and a functional group number of usually 2.0 to 8.0 can be used in combination. Two or more of these may be used in combination.

  The polyether polyol is a polymer of alkylene oxide obtained from one or more of ethylene oxide, propylene oxide, 1,2-butylene oxide, tetrahydrofuran, etc .; trifunctional such as sucrose, sorbitol, erythritol, pentaerythritol, glycerin, etc. Examples include adducts of the above alcohols with the above alkylene oxides; adducts of aliphatic amines and aromatic amines with the above alkylene oxides, and the like. In addition, known polyether polyols such as Mannich-modified polyols and polymer polyols can be used.

  The polyester polyol that can be used in combination with the specific polyol includes one or more aromatic or aliphatic carboxylic acids such as benzoic acid, phthalic acid, terephthalic acid, isophthalic acid, succinic acid, adipic acid, maleic acid, and trimellitic acid. 2-ethylhexanol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,2-butanediol 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, glycerin, trimethylolpropane, Penta Obtained by esterification reaction of one or more monovalent to tetravalent alcohols such Risuritoru, hydroxyl value typically 100-500, functional groups and polyester polyols typically 1.5 to 3.0.

  In addition to the above, compounds having two or more active hydrogens in one molecule, such as alcohols such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, glycerin, alkanolamines such as diethanolamine, triethanolamine, etc. Can also be used together.

  The amount of the specific polyol used in the composition for rigid polyurethane foam of the present invention is 60% by weight or more, preferably 70% by weight or more, more preferably 80% by weight, based on the total polyol. Good. If the amount used is less than 60% by weight, the effect of improving the flame retardancy and adhesiveness of the rigid urethane foam cannot be obtained. When the total amount of polyol is not a specific polyol, the aforementioned polyether polyol and / or polyester polyol are used as the remaining polyol.

The catalyst in the rigid polyurethane foam composition of the present invention is a combination of an amine (excluding imidazole) catalyst (a), an imidazole catalyst (b), a quaternary ammonium catalyst (c), and a potassium catalyst (d). formed is, a catalyst (a) ~ 0.01 to 20 parts by weight each usage with respect to 100 parts by weight polyol (d), the [(c) + (d)] / (b) 2 to 40 It is a weight ratio.

Examples of the amine catalyst (a) include triethylenediamine, N, N-dimethylhexylamine and the like. Among amine-based catalysts, especially bisdimethylaminoethyl ether and pentamethyldiethylenetriamine, which mainly act as a foaming catalyst, that is, a catalyst that promotes the reaction between isocyanate and water (ureation / CO ₂ generation) Is preferred.

  Examples of the imidazole catalyst (b) include 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole and the like, and commercially available products such as ethylene glycol and the like. Some of them are in solution, and any of them can be used alone or in combination of two or more. These imidazole-based catalysts (b) mainly contribute to the improvement of the adhesiveness of the rigid polyurethane foam as a resinification catalyst.

  Examples of the quaternary ammonium catalyst (c) include hydroxyethyltrimethylammonium salt, hydroxypropyltrimethylammonium salt and the like, and commercially available products include those in which these are combined and those in a solution such as diethylene glycol. These can be used alone or in combination of two or more. These quaternary ammonium-based catalysts (c) mainly contribute to the improvement of flame retardancy of rigid polyurethane foams as isocyanate trimerization catalysts.

  Examples of the potassium-based catalyst (d) include potassium acetate, potassium octylate and the like, and commercially available products in which these are solutions of diethylene glycol or the like are used either alone or in combination of two or more. I can do it. These potassium-based catalysts (d) also contribute to improving the flame retardancy of rigid polyurethane foams as an isocyanate trimerization catalyst.

  The amount of each of the catalysts (a) to (d) used is usually 0.01 to 20 parts by weight with respect to 100 parts by weight of the polyol, and the optimum range is appropriately determined depending on the desired reaction rate.

  By the way, since any catalyst contributes to the reaction rate at the time of producing a rigid polyurethane foam, for example, if the imidazole catalyst (b) is increased, the quaternary ammonium catalyst (c) is decreased, and the desired physical properties; It is important to balance according to adhesiveness, flame retardancy, reaction rate, and the like.

In rigid polyurethane foam composition of the present invention, the weight ratio of the imidazole-based catalyst (b), 4 quaternary ammonium U beam based catalyst (c), potassium-based catalyst (d) is [(c) + (d)] / It is 2-40 in (b), Preferably it is 3-37, More preferably, it is 4-35. On the other hand, the weight ratio of the quaternary ammonium U beam based catalyst (c), potassium-based catalysts (d) are 0.1 to 20 in (c) / (d), preferably 0.2 to 18, further Preferably it is 0.3-15. In addition to these catalysts, examples of catalysts that can be used in combination include tin-based catalysts such as dibutyltin dilaurate and tin octylate, and lead-based catalysts such as lead octylate.

In the composition for rigid polyurethane foam of the present invention, water acts as a foaming agent by generating carbon dioxide gas by reaction with polyisocyanate. In addition, in the range that the water added more than half of the foaming action, that is, in the range that the water added more than half of the amount of the gas responsible for the foaming action is used, it is possible to use a foaming agent other than water together I can do it. Examples of foaming agents that can be used in combination include foaming agents having an ozone depletion coefficient of 0.8 or less, for example, HFC foaming agents such as HCFC-141b, HFC-245fa, and HFC-365mfc, and HC foaming agents such as pentane and cyclopentane. In addition, liquefied carbon dioxide gas, supercritical carbon dioxide, and the like can also be used. The blending amount of the foaming agent is appropriately selected depending on the density of the target rigid urethane foam. The density of the rigid polyurethane foam of the present invention is 20 to 50 kg / m ³ , and if the foaming agent is water, The approximate amount used is about 2 to 15 parts per 100 parts by weight of polyol.

  The surfactant used in the composition for rigid polyurethane foam of the present invention may be any of nonionic, anionic, and cationic surfactants, preferably nonionic surfactants, particularly silicone surfactants. preferable. The amount of these surfactants used is 0.5 to 10 parts by weight with respect to 100 parts by weight of the polyol, and two or more kinds of surfactants may be used.

  In the composition for rigid polyurethane foams of the present invention, various compounds can be used as additives and auxiliaries depending on the application as other 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 mentioned above are not particularly limited, and if they are used for the purpose of improving physical properties and operability in ordinary resins, they can have a significant adverse effect on the urethanization reaction. It can be used as long as it is not.

  Next, the manufacturing method of the rigid polyurethane foam which concerns on this invention is demonstrated.

  The method for producing a rigid polyurethane foam according to the present invention is a method of mixing a polyisocyanate and a polyol in the presence of at least a catalyst, water as a blowing agent, and a surfactant. And it uses the polyol and catalyst as described below, It is characterized by the above-mentioned.

(1) Use phthalic acid and / or terephthalic acid as the aromatic carboxylic acid component, succinic acid and / or adipic acid as the aliphatic carboxylic acid component, and diethylene glycol, triethylene glycol, number average molecular weight as 600 or less as the alcohol component A polyol containing 60% by weight or more of a polyester polyol obtained by esterification using at least one selected from the group of polyethylene glycols.

(2) amine (excluding imidazole) based catalyst (a), imidazole-based catalyst (b), Ri formed from a combination of quaternary ammonium-based catalyst (c) and potassium-based catalyst (d), the catalyst (a) ~ (d ) Is 0.01 to 20 parts by weight with respect to 100 parts by weight of polyol, and [(c) + (d)] / (b) is 2 to 40 parts by weight.

  The above polyol and catalyst are as described above. In the method for producing a rigid polyurethane foam according to the present invention, usage forms of the catalyst, water as a foaming agent, and a surfactant are not limited to the above-described composition for rigid polyurethane foam. For example, the surfactant can be used by mixing with a polyisocyanate liquid. In some cases, the polyisocyanate, polyol, and catalyst components may be handled as three or more kinds of raw material liquids without mixing until just before the urethanization reaction. However, practically, a method of mixing the polyisocyanate and the composition for rigid polyurethane foam of the present invention is often employed. That is, a method of mixing, foaming and curing two liquids of a polyisocyanate and a hard polyurethane foam composition using an apparatus described later is employed.

  The polyisocyanate is not particularly limited as long as it is an organic 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 the polyisocyanate liquid, in addition to these polyisocyanates, additives and auxiliaries may be mixed with the polyisocyanate and used depending on the application. For example, for the purpose of improving the mixing property with the hard polyurethane foam composition described above, a surfactant that is also used in the hard 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. Moreover, a flame retardant may be used together for the purpose of improving flame retardancy and adjusting viscosity. Usually, chloroalkyl phosphates such as tris (betachloroethyl) phosphate and tris (betachloropropyl) phosphate are used. Additives and auxiliaries other than those mentioned above are not particularly limited, and if they are used for the purpose of improving physical properties and operability in ordinary resins, they can have a significant adverse effect on the urethanization reaction. Otherwise, anything can be used.

  The rigid polyurethane foam obtained by the present invention has a urethane bond, a urea bond and an isocyanurate bond. The isocyanurate bond is generated by trimerizing an isocyanate group with a catalyst, and can improve mechanical strength and heat resistance.

  In the present invention, the isocyanate index when mixing the polyisocyanate and the polyol is important. The isocyanate index in the present invention is [(mole number of isocyanate group) / (mole number of all active hydrogen groups excluding water) × 100] excluding polyisocyanate consumed by reaction with water, and 200 to 400 , Preferably 210-390, more preferably 220-380. When the isocyanate index is less than 200, the obtained rigid polyurethane foam may not have sufficient flame retardancy, and when it exceeds 400, the brittleness of the obtained rigid polyurethane foam increases and the adhesive strength decreases. There is a tendency.

  The closed cell ratio of the rigid polyurethane foam obtained in the present invention is usually 80% or more, preferably 85% or more, and more preferably 90% or more. When the closed cell ratio is less than 80%, the flame retardancy decreases. The upper limit of the closed cell ratio is 100%.

The density of the rigid polyurethane foam of the present invention is represented by the core density when a free foam is prepared by a known method, and is usually 20 to 60 kg / m ³ , preferably 23 to 58 kg / m ³ , more preferably 25 to 55 kg. / M ³ . When the density is less than 20 kg / m ³ , the obtained rigid polyurethane foam does not have sufficient flame retardancy and mechanical strength, and when it exceeds 60 kg / m ³ , the cost becomes high.

  In producing the rigid polyurethane foam, any apparatus can be used as long as the polyisocyanate liquid and the rigid polyurethane foam composition 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 A spray foaming machine or the like can be used, and is appropriately selected depending on the application and the form of the product. In addition, when manufacturing a rigid polyurethane foam, each liquid temperature of the composition for rigid polyurethane foams and a polyisocyanate liquid is normally adjusted to 20-60 degreeC.

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

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these Examples, unless the summary is exceeded. Unless otherwise specified, “parts” and “%” in the examples mean “parts by weight” and “% by weight”, respectively.

[Synthesis of polyester polyol]
Polyester polyols used in Examples and Comparative Examples were synthesized by known methods, and the raw material composition, acid value, hydroxyl value, and viscosity (25 ° C.) are shown in Table 1 as polyols 1 to 4. Each analysis was performed according to JIS K1557 (2007).

Examples 1-4 and Comparative Examples 1-5:
[Preparation of composition for rigid polyurethane foam]
Compositions 1-9 for rigid polyurethane foam were prepared using the raw materials and blends shown in Tables 2-1 and 2-2. The compounding ratio in the table | surface was shown by the weight part (pbw).

  In the formulation examples of Table 2-1 and Table 2-2, the raw materials described in Table 3 below were used.

Examples 5-8 and Comparative Examples 6-10:
[Production of rigid polyurethane foam]
Production and evaluation of rigid polyurethane foam were carried out according to the methods shown below at the blending ratios shown in Table 4-1 and Table 4-2. The evaluation results are shown in Tables 4-1 and 4-2.

<Manufacturing method>
After mixing the polyisocyanate liquid and the composition for rigid polyurethane foam described in Table 2-1 and Table 2-2, the mixture was poured into an injection box and subjected to free foaming to produce a rigid polyurethane foam (free foam). The polyisocyanate liquid used was polymeric MDI (“Millionate MR-200” manufactured by Nippon Polyurethane Industry Co., Ltd.), and the isocyanate index during mixing was shown in Tables 4-1 and 4-2.

<Foaming conditions>
Room temperature: 23-25 ° C
Liquid temperature: 25 ° C
Stirring: 3000 rpm × 5 to 7 seconds Injection box: Wooden (200 mm × 200 mm × 200 mm) top opening Demolding time: 30 minutes after mixing

  Evaluation of the obtained rigid polyurethane foam was performed by the following method.

<Evaluation method>
(1) Core density:
It measured based on JIS A9511 (2003).

(2) Flame retardancy:
A “gas torch 170” manufactured by Fujiwara Sangyo Co., Ltd. was used and evaluated by a flame penetration test as follows. That is, the core part of the produced free foam was cut out into 200 mm × 200 mm × 25 mm, and set so that the flame of the gas torch hit the foam center part at a distance of 10 cm from the tube tip. After igniting the gas torch, the time until the flame penetrated the foam was measured and evaluated according to the following criteria.

○: It did not penetrate for more than 3 minutes.
Δ: Penetrated in 2 minutes to less than 3 minutes.
X: Penetrated in less than 2 minutes.

(3) Compressive strength:
Measured in accordance with JIS A9511 (2003), the foaming was indicated in the horizontal direction (//) and the vertical direction (⊥).

(4) Dimensional stability:
The dimensional change rate (horizontal and vertical direction of foaming) after 24 hours at room temperature of the sample whose core density was measured was measured and evaluated according to the following criteria.

○: Both horizontal and vertical are less than 3%.
Δ: Both horizontal and vertical are less than 5%.
X: Either horizontal or vertical is 5% or more.

(5) Adhesiveness:
Create free form using kraft paper surface material, cut out the bottom center part to 5 × 10 × 3cm, and create a test piece. After peeling off the longitudinal direction edge part of a kraft paper surface material, it pulled in the thickness direction with the tensile tester, the peeling strength (N / 5cm) was measured, and the following references | standards evaluated.

A: 12 N / 5 cm or more.
(Triangle | delta): It is 9 N / 5cm or more.
X: Less than 9 N / 5 cm.

(6) Brittleness:
The surface and bottom of the rigid polyurethane foam were palpated and qualitatively observed, and evaluated according to the following criteria.

○: Almost no brittleness.
Δ: Some brittleness.
X: It is brittle.

  From the above results, the following is mainly clear.

(1) Comparison results between Example and Comparative Examples 1 and 2:
In contrast to Examples using Polyol-1 and -2 in which aromatic carboxylic acid and aliphatic carboxylic acid are combined, Comparative Example 1 using Polyol-3 containing only aromatic carboxylic acid is poor in adhesion and brittleness. Comparative Example 2 using polyol-4 containing only an aromatic carboxylic acid has poor flame retardancy.

(2) Comparison results between Example and Comparative Examples 3 and 4:
Imidazole-based catalyst (b), 4 quaternary ammonium U beam based catalyst (c), examples of 10,25,40 weight ratio of potassium-based catalyst (d) is in [(c) + (d)] / (b) On the other hand, Comparative Example 3 in which [(c) + (d)] / (b) is 1 has poor flame retardancy, and Comparative Example 4 in which [(c) + (d)] / (b) is 50 Has poor adhesion.

(3) Comparison results between Example and Comparative Examples 5 and 6:
In contrast to the example of the present invention having an isocyanate index of 300, Comparative Example 5 having an isocyanate index of 170 has poor flame retardancy, and Comparative Example 6 having an isocyanate index of 450 has poor adhesion.

(4) Comparison results between Example and Comparative Example 7:
The comparative example 7 which used only 40 weight part with respect to the Example which used 70 weight part or more of polyester polyol prescribed | regulated by this invention has a bad flame retardance.

Claims (3)

A composition for a rigid polyurethane foam used for mixing with a polyisocyanate to form a rigid polyurethane foam under a condition of an isocyanate index of 200 to 400, comprising at least a polyol, a catalyst, water as a blowing agent, and a surface activity. A composition for rigid polyurethane foam comprising an agent and using the polyol and catalyst described below.
(1) Use phthalic acid and / or terephthalic acid as the aromatic carboxylic acid component, succinic acid and / or adipic acid as the aliphatic carboxylic acid component, and diethylene glycol, triethylene glycol, number average molecular weight as 600 or less as the alcohol component A polyol containing 60% by weight or more of a polyester polyol obtained by esterification using at least one selected from the group of polyethylene glycols.
(2) amine (excluding imidazole) based catalyst (a), imidazole-based catalyst (b), Ri formed from a combination of quaternary ammonium-based catalyst (c) and potassium-based catalyst (d), the catalyst (a) ~ (d ) Is 0.01 to 20 parts by weight with respect to 100 parts by weight of polyol, and [(c) + (d)] / (b) is 2 to 40 parts by weight.   2. The polyester polyol according to claim 1, wherein the ratio of succinic acid and / or adipic acid in the total carboxylic acid component is 10 to 80 mol%, and the hydroxyl value of the polyester polyol is 100 to 400 (mgKOH / g). A composition for rigid polyurethane foam. In the production of a rigid polyurethane foam by mixing polyisocyanate and polyol in the presence of at least a catalyst, water as a blowing agent, and a surfactant, the polyol and catalyst described below are used, and the isocyanate index is 200. A method for producing a rigid polyurethane foam, comprising mixing a polyisocyanate and a polyol under a condition of ˜400.
(1) Use phthalic acid and / or terephthalic acid as the aromatic carboxylic acid component, succinic acid and / or adipic acid as the aliphatic carboxylic acid component, and diethylene glycol, triethylene glycol, number average molecular weight as 600 or less as the alcohol component A polyol containing 60% by weight or more of a polyester polyol obtained by esterification using at least one selected from the group of polyethylene glycols.
(2) amine (excluding imidazole) based catalyst (a), imidazole-based catalyst (b), Ri formed from a combination of quaternary ammonium-based catalyst (c) and potassium-based catalyst (d), the catalyst (a) ~ (d ) Is 0.01 to 20 parts by weight with respect to 100 parts by weight of polyol, and [(c) + (d)] / (b) is 2 to 40 parts by weight.