JP2011184643A - Polyester polyol, and method for manufacturing rigid polyurethane foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester polyol that contains a lignin-based substance in a dissolution state; and a method for manufacturing a polyurethane, especially a rigid polyurethane foam that is excellent in the mechanical strengths and flame retardancy by using it. <P>SOLUTION: The polyester polyol composition containing 1-60 wt.% of a lignin-based substance is characterized in that this polyester polyol is a product obtained by the esterifying reaction of a carboxylic acid component containing an aromatic carboxylic acid with an alcohol component containing a polyethylene glycol of a molecular weight or number-average molecular weight of 100-600; and there is provided the rigid urethane foam using this. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polyester polyol composition containing a lignin-based substance and a method for producing a rigid polyurethane foam having excellent flame retardancy using the composition.

  In recent years, resource problems such as the depletion of natural resources such as petroleum, and environmental problems such as an increase in carbon dioxide emissions due to mass consumption of petrochemical products have attracted attention. Research and development using biomass as a so-called carbon-neutral raw material obtained from resources is underway. In particular, since lignin present in natural plants is a compound having an aromatic ring, it is highly expected as a raw material for phenols and the like.

  Since lignin is an amorphous polyphenol, it is difficult to react and isolate specific compounds, and although there are very few industrial products using these as raw materials, various studies have been made on how to use lignin as a plastic material. It was. For example, a method in which kraft lignin is dissolved in PEG (polyethylene glycol) and reacted with polyisocyanate to produce polyurethane is exemplified. (Non-Patent Document 1)

  On the other hand, since rigid polyurethane foam has excellent heat insulating properties and flame retardancy, it is widely used in refrigerator rooms, refrigerators, freezer rooms, freezers, heat insulating materials for general buildings, heat insulating panels, and the like. Rigid polyurethane foam is generally prepared by mixing a polyisocyanate, a polyether polyol and / or polyester polyol, a foaming agent, and, if necessary, a catalyst or surfactant (premix solution) and mixing them. And produced by a method of foaming and curing in a short time.

  It has been proposed to further improve the flame retardancy by applying a lignin-based material to such a rigid polyurethane foam. For example, a lignin sulfonate is dissolved in a polyol and then reacted with a polyisocyanate to produce a hard material. Methods for producing polyurethane foam are known. (Patent Documents 1 and 2) Similarly, a method of producing a rigid polyurethane foam by dissolving a lignin-based substance in a polyol and then reacting with a polyisocyanate has been proposed. (Patent Document 3)

  Polyols include ethylene glycol, diethylene glycol, 1,4-butanediol, trimethylolpropane, glycerin, triethanolamine, pentaerythritol, sorbitol and other low molecular weight polyols, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, polyether Examples include polyol, polycaprolactone, polyester polyol, polycarbonate polyol, acrylic polyol and the like.

  However, in the literature and patent examples published so far, the only polyols used with lignin-based substances are diethylene glycol, polyethylene glycol, glycerin, and polyether polyols. For example, short-chain polyols such as diethylene glycol and glycerin can not be used. The resulting polyurethane tends to be hard and brittle, and even when polyethylene glycol or polyether polyol is used, the resulting polyurethane is insufficient in terms of mechanical strength and flame retardancy.

  On the other hand, although there is an example, an example in which a lignin-based material is actually dissolved in a polyester polyol, and furthermore, when applying a lignin-based material to polyurethane production, an optimal polyester polyol composition and lignin-based material mixing ratio No examples have been reported. The reason is considered that the lignin-based substance is difficult to dissolve in a general-purpose polyester polyol obtained from, for example, adipic acid and 1,4-butanediol.

  Generally, polyester polyols obtained by esterification reaction of polyhydric carboxylic acid and polyhydric alcohol are used as polyol components in producing polyurethanes represented by paints, adhesives, sealants, elastomers, and hard or flexible polyurethane foams. Compared to other polyether polyols and alkylene glycols, it is excellent in mechanical strength and flame retardancy when it becomes, for example, a polyurethane foam, and thus is particularly suitably used in the production of rigid polyurethane foam.

If such a polyester polyol can be used for polyurethane production by containing a lignin-based substance, it will be very significant as an improvement in mechanical strength and flame retardancy, as well as in dealing with the above-mentioned resources and environmental problems.

Japanese Patent Publication No. 50-9814 JP-A 51-86597 JP 2006-326943 A

Journal of Japan Paper Technology Vol. 44, No. 8, pp. 849-855 (1990)

  Accordingly, an object of the present invention is to provide a polyester polyol composition containing a lignin-based substance, and further to use it to produce a polyurethane excellent in mechanical strength and flame retardancy, particularly a rigid polyurethane foam. Is to provide.

  As a result of intensive studies by the present inventors to achieve the above object, a polyester polyol composition suitable for polyurethane production can be obtained by setting the carboxylic acid component and the alcohol component of the polyester polyol to a specific composition and further containing a lignin-based substance. Furthermore, the present invention was completed by obtaining the knowledge that the above-mentioned object can be easily achieved by using the composition as a part of the polyol component in producing the rigid polyurethane foam.

  In addition, when a polyester polyol is produced by the esterification reaction between a specific carboxylic acid component and an alcohol component, a polyester polyol composition having a uniform and high content of the lignin material can be obtained by coexisting the lignin material. Furthermore, by using it as a part of the polyol component when producing a rigid polyurethane foam, the inventors have obtained the knowledge that the above-mentioned object can be easily achieved, and completed the present invention.

That is, the gist of the present invention is as follows.
(1) A polyester polyol composition containing 1 to 60% by weight of a lignin-based substance, wherein the polyester polyol includes a carboxylic acid component containing an aromatic carboxylic acid, and a polyethylene glycol having a molecular weight or number average molecular weight of 100 to 600 A polyester polyol composition obtained by an esterification reaction with an alcohol component containing
(2) The aromatic carboxylic acid is at least one or two or more selected from the group consisting of phthalic acid, terephthalic acid and isophthalic acid, and the amount used is 20 mol% or more in the total carboxylic acid component. The polyester polyol composition according to (1) above.
(3) The polyester polyol composition as described in (1) or (2) above, wherein succinic acid and / or adipic acid is further used as the carboxylic acid component in an amount of 80 to 20 mol% in the total carboxylic acid component.
(4) The polyester polyol composition according to any one of the above (1) to (3), which has a hydroxyl value of 30 to 500 mgKOH / g as a whole composition and a viscosity at 25 ° C. of 30000 mPa · s or less. object.
(5) The above (1) to (1), wherein the lignin-based substance is at least one selected from the group consisting of kraft lignin, acid hydrolyzed lignin, solvolytic lignin, alkaline lignin and lignin sulfonic acid. The polyester polyol composition according to any one of (4).
(6) The polyester polyol composition according to any one of (1) to (5), wherein the esterification reaction is performed in the presence of a lignin-based substance.
(7) In the method for producing a rigid polyurethane foam using at least a polyol, a foaming agent, a catalyst, a surfactant and a polyisocyanate, the polyester polyol composition according to any one of (1) to (6) is used as the polyol. The manufacturing method of the rigid polyurethane foam used 20weight% or more of.
(8) The manufacturing method of the rigid polyurethane foam as described in said (7) using water as a foaming agent.
(9) The manufacturing method of the rigid polyurethane foam as described in said (7) or (8) whose isocyanate index is 50-500.

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

  Hereinafter, the present invention will be described in detail.

  Since lignin present in natural plants is present in a state closely related to cellulose and hemicellulose (polysaccharide), when lignin is used, its isolation operation is necessary. Lignin isolation methods include extraction with an organic solvent (eg dioxane-water), dissolution with an alkaline aqueous solution (digestion), hydrolysis of polysaccharides with acid to obtain a residue, explosion method, enzyme A processing method etc. are mentioned. The lignin-derived substance isolated by these methods is referred to herein as a lignin-based substance.

  In the present invention, the lignin-based substance obtained by any of the above methods or other methods can be used, and a mixture of two or more types may be used. Moreover, the plant raw material used as the base of a lignin-type substance does not have a problem even if it is a mixture of a thing of a different kind irrespective of the kind of wood or vegetation. Considering the solubility in polyester polyol, lignin-based substances in black liquor produced at kraft pulp mill (kraft lignin), lignin-based substances in black liquor produced at soda pulp mill (alkali lignin), sulfite pulp It is preferable to use a lignin-based substance (lignin sulfonate) in black liquor produced in a factory and a lignin-based substance (acid-hydrolyzed lignin) produced by acid treatment of plant materials. As a method for isolating these lignin substances, for example, kraft lignin can be obtained by neutralizing the black liquor with carbon dioxide gas, hydrochloric acid or the like, and centrifuging or filtering. As mentioned above, since lignin present in natural plants exists in a state closely related to cellulose and hemicellulose (polysaccharide), separation thereof may be very difficult. You may use it in the state which hemicellulose etc. mixed partially.

  In the polyester polyol composition of the present invention, the lignin-based material may be mixed with the polyester polyol to form a polyester polyol composition, or the lignin-based material may be produced when the polyester polyol is produced by an esterification reaction of a carboxylic acid component and an alcohol component. May be used as a polyester polyol composition. When mixing a lignin-type substance with a polyester polyol, melt | dissolution is accelerated | stimulated by heating to about 60-120 degreeC as needed. At this time, depending on the conditions, a part of the lignin-based substance may react and be taken into the polyester polyol molecule. Similarly, when a lignin-based substance is allowed to coexist at the time of production of the polyester polyol, the lignin-based substance may react and be taken into the polyester polyol molecule. Since the lignin-based material is easily dissolved in the polyester polyol, that is, the polyester polyol composition is likely to be more uniform, the lignin-based material is preferably added together with other raw materials during the production of the polyester polyol.

  The content of these lignin-based substances in the polyester polyol composition is 1 to 60% by weight, preferably 3 to 55% by weight, more preferably 5 to 50% by weight based on the total weight of the composition containing the lignin-based substance. %. When the content is less than 1%, the effect of improving the flame retardancy and mechanical strength cannot be obtained, and it is insufficient as a countermeasure for resource problems and environmental problems. On the other hand, if the content exceeds 60% by weight, the solubility limit is exceeded and non-uniformity occurs, or the viscosity of the polyester polyol is remarkably increased. When it is dissolved by separately mixing with polyester polyol, it becomes difficult to dissolve when it exceeds about 30% by weight, but about 60% by weight when a lignin-based substance is coexisted with a carboxylic acid component and an alcohol component during the production of polyester polyol. Can be mixed. That is, when it is desired to contain a large amount of lignin-based material, it is desirable to obtain a polyester polyol by esterifying the carboxylic acid component and the alcohol component in the presence of the lignin-based material. When the lignin-based substance is allowed to coexist during the esterification reaction, the content of the lignin-based substance can be increased, so the structure is unknown, but in the esterification reaction, a part of the lignin-based substance is It is presumed that the polyester polyol molecules are reacted and incorporated.

  The polyester polyol composition of the present invention is preferably a homogeneous solution in which a lignin-based material is dissolved, but depending on the type and amount of the lignin-based material used, a part of the polyester polyol composition may remain undissolved or non-uniform. is there. In that case, it is desirable to use the polyester polyol composition after filtering, but it is possible to use it as it is if it does not have an adverse effect upon urethanization.

  As the carboxylic acid component constituting the polyester polyol of the present invention, an aromatic carboxylic acid is used. Examples of the aromatic carboxylic acid include 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, and the like. Examples thereof include substituted compounds, and at least one of them can be used in combination. Since high flame retardancy and mechanical strength are generally required in the use of rigid polyurethane foam, at least one or two or more selected from phthalic acid, terephthalic acid, and isophthalic acid are 20 mol% or more of the total carboxylic acid component, It is more preferable to use 25 mol% or more and 30 mol% or more, and the total amount may be aromatic carboxylic acid.

  However, from the viewpoint of reducing the viscosity of the polyester polyol and improving the brittleness and adhesion of the rigid polyurethane foam, in addition to these aromatic carboxylic acids, at least one or more selected from aliphatic carboxylic acids are used in combination. It is desirable to do. For example, C1-C18 aliphatic monocarboxylic acids such as acetic acid and 2-ethylhexanoic acid, C2-C12 aliphatic polyvalent carboxylic acids such as succinic acid, adipic acid, maleic acid and malic acid Among them, it is preferable to use succinic acid and / or adipic acid in combination, and the amount used is 20 to 80 mol%, preferably 25 to 75 mol% of the total carboxylic acid. More preferably, it is 30-70 mol%.

  Each carboxylic acid component may be an acid anhydride such as phthalic anhydride or a derivative such as methyl ester 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.

  Polyethylene glycol having a molecular weight or a number average molecular weight of 100 to 600 is used as the alcohol component constituting the polyester polyol. Examples of the polyethylene glycol having a molecular weight or number average molecular weight of 100 to 600 in the present invention include polyethylene glycol having a number average molecular weight of 200, 400, or 600 in addition to diethylene glycol, triethylene glycol, tetraethylene glycol, and the like. Or may be used in combination. Among these, it is desirable to use triethylene glycol or polyethylene glycol having a number average molecular weight of 400 or less in consideration of cost, viscosity of the obtained polyester polyol, physical properties of the rigid polyurethane foam, etc. For example, diethylene glycol and number average molecular weight 400 are preferable. It is also possible to use a mixture of polyethylene glycol. Other alcohol components include C1-C18 aliphatic or aromatic monoalcohols such as 2-ethylhexanol and phenol, carbon numbers such as ethylene glycol, 1,4-butanediol, glycerin and pentaerythritol. 2-10 aliphatic or aromatic polyhydric alcohols can be used together, but considering the cost, viscosity of polyester polyol, physical properties of rigid polyurethane foam, etc., the amount used is 20 mol% or less of the total alcohol components. It is desirable to keep it. The lignin-based substance used in the present invention has both a carboxylic acid group and a hydroxyl group (alcoholic / phenolic), and is presumed to partially react in the esterification reaction and be incorporated into the polyester polyol molecule. Since it cannot be specified, it is not included in the calculation of the amount of use of these alcohol components and carboxylic acid components.

  The hydroxyl value of the polyester polyol composition is usually in the range of 30 to 500 mgKOH / g, preferably 40 to 470 mgKOH / g, more preferably 50 to 450 mgKOH / g. When the hydroxyl value is smaller than 30 mgKOH / g, the viscosity of the polyester polyol may be remarkably increased or the mechanical strength of the resulting polyurethane may be lowered. On the other hand, if it is larger than 500 mgKOH / g, the molecular weight distribution of unreacted alcohol is increased and the brittleness of the polyurethane is deteriorated, and the amount of polyisocyanate used is increased and the so-called liquid ratio between the polyol composition and the polyisocyanate exceeds the proper range. There is a case. The polyester polyol composition of the present invention contains a lignin-based substance in a dissolved state. The hydroxyl value of lignin is also included in the hydroxyl value, and the hydroxyl value is measured in a state where lignin is dissolved in the polyester polyol.

  The viscosity at 25 ° C. of the polyester polyol composition of the present invention is usually 30000 mPa · s or less, preferably 25000 mPa · s or less, more preferably 20000 mPa · s or less. When it is higher than 30000 mPa · s, the handling may be hindered. The viscosity is also measured in a state where the lignin-based substance is dissolved, like the hydroxyl value.

  Moreover, as a method for reducing the viscosity of the polyester polyol composition, monovalent alcohols such as methanol, ethanol, isopropanol, and 2-ethylhexanol can be used in combination as described above. However, when these monohydric alcohols are used, it is important to prevent the hydroxyl value from deviating from the above range. In addition, distilling out of the reaction system in the synthesis of the polyester polyol may deteriorate the yield, or may adversely affect the strength and heat resistance of the polyurethane foam using the obtained polyester polyol composition. It is preferable to use in the range which does not become a problem.

  The polyester polyol in this invention can be manufactured in accordance with the manufacturing method of a well-known polyester polyol. The general production conditions are listed below. In addition, as described above, the lignin-based substance may be dissolved by separately mixing after the production of the polyester polyol, or may be added to the reaction system together with the carboxylic acid component and the alcohol component during the production of the polyester polyol. From the viewpoint of the reaction operation, it is preferable to add it to the reaction system after mixing and dissolving with the alcohol component in advance. However, when an esterification reaction is performed as a raw material, depending on the reaction conditions, components such as moisture and sulfur, impurities, and the like contained in the lignin-based substance may be precipitated during the reaction or may be distilled together with by-product water.

  In the esterification reaction in the present invention, 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.

  The polyester polyol composition of the present invention becomes polyurethane by urethanation reaction with polyisocyanate, and at the same time, reaction of polyisocyanate and water, reaction between polyisocyanates and the like occur. In this case, the catalyst used for the production of polyester polyol is It is desirable not to affect the reaction behavior of these reactions. Therefore, among the above esterification catalysts, orthotitanate is preferable. Moreover, the usage-amount 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 component 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 polyester 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. When a lignin-based substance having a sulfonic acid group such as lignin sulfonic acid is used, it may be difficult to determine the unreacted carboxyl group of the carboxylic acid used. Similarly, it may be difficult to determine the unreacted carboxyl group of the carboxylic acid used due to the influence of phenolic hydroxyl group in the lignin-based substance, hydrochloric acid or sulfuric acid used at the time of extraction of the lignin-based substance. In those cases, the end point of the reaction can also be determined by the amount of water by-produced in the esterification reaction.

  In addition, in order to keep the average number of functional groups and hydroxyl value of polyester polyol at a certain target value, it is important not to distill alcohol components in an equilibrium state out of the reaction system as much as possible during the ester exchange reaction during the esterification reaction. It is. If the alcohol component is distilled too much, the average number of functional groups of the polyester polyol will be different from that of the original product design, and the hydroxyl value will be reduced. As a result, the viscosity of the resulting polyester polyol will be remarkably high. May grow. 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 a reaction mode of polyester polyol production in the present invention, normal batch equipment or continuous equipment can be applied, but the reaction time is long, and the viscosity of the obtained polyester polyol is compared with the alcohol component used as a raw material. The batch reaction is preferable because it becomes considerably high.

  The polyester polyol composition of the present invention is particularly useful as a polyol in the production of rigid polyurethane foams, and is extremely useful because it can improve physical properties such as flame retardancy and mechanical strength of the obtained rigid polyurethane foams.

  Next, production of a rigid polyurethane foam using the polyester polyol composition of the present invention will be described.

  In the production of rigid polyurethane foam, the polyester polyol composition of the present invention is usually used as a composition (premix liquid) together with other polyols, foaming agents, catalysts, surfactants and other auxiliaries as necessary. The And a rigid polyurethane foam is obtained by mixing, foaming, and hardening a premix liquid and polyisocyanate in a short time.

  As the polyol, in addition to the polyester polyol composition described above, 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.

  Examples of the polyether polyol include polymers of alkylene oxides obtained from one or more of ethylene oxide, propylene oxide, 1,2-butylene oxide, tetrahydrofuran, etc .; sucrose, sorbitol, erythritol, pentaerythritol, glycerin, etc. And adducts of the above trifunctional or higher 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 used as a polyol other than the polyester polyol composition of the present invention includes, as a carboxylic acid component, benzoic acid, phthalic acid, terephthalic acid, isophthalic acid, succinic acid, adipic acid, maleic acid, trimellitic acid One or more of aromatic or aliphatic carboxylic acids such as 2-ethylhexanol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, di Propylene glycol, tripropylene glycol, polypropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,6-hexanediol, 3 -Mechi -1,5-pentanediol, glycerin, trimethylolpropane, pentaerythritol, etc., obtained by esterification with one or more of 1 to 4 valent alcohols, the hydroxyl value is usually 100 to 500, the number of functional groups Is usually 1.5 to 3.0 polyester polyol.

  In addition to the above, as the polyol, two active hydrogens in one molecule, such as alcohols such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol and glycerin, alkanolamines such as diethanolamine and triethanolamine, etc. The compounds having the above can also be used in combination.

  The amount of the polyester polyol composition containing the lignin of the present invention in the rigid polyurethane foam composition is 20% by weight or more, preferably 25% by weight or more, more preferably 30% by weight, based on the polyol. The total amount may be the polyester polyol composition of the present invention. If the amount used is less than 20% by weight, the effect of improving the flame retardancy and mechanical strength of the rigid polyurethane foam cannot be obtained. When the total amount of polyol is not the polyester polyol composition of the present invention, the aforementioned polyether polyol and / or polyester polyol are used as the remaining polyol.

  As the foaming agent, those commonly used in the production of rigid polyurethane foam can be used, and foaming agents having an ozone depletion coefficient of 0.8 or less, for example, HFC-based foaming such as HCFC-141b, HFC-245fa, HFC-365mfc, etc. In addition to HC-based blowing agents such as an agent, pentane and cyclopentane, water, liquefied carbon dioxide gas, supercritical carbon dioxide and the like can also be used. In consideration of the environment, it is preferable to use water as a foaming agent, and water acts as a foaming agent by reacting with polyisocyanate to generate carbon dioxide gas. The combination and use amount of these foaming agents are appropriately selected depending on physical properties such as the density of the target rigid urethane foam.

  As a catalyst, the well-known catalyst used for manufacture of a normal polyurethane foam can be used. For example, amines such as triethylenediamine and N, N-dimethylhexylamine, hydroxylamines, imidazoles, quaternary ammonium salts, potassium compounds such as potassium acetate and potassium octylate, dibutyltin dilaurate, octyl Examples thereof include a metal catalyst such as a tin catalyst such as tin oxide and a lead catalyst such as lead octylate. Similarly, the combination and use amount of these catalysts are also appropriately selected depending on the desired physical properties and reaction rate.

  The surfactant may be any of nonionic, anionic and cationic, but is preferably a nonionic surfactant, and particularly preferably a silicone surfactant.

  As other auxiliaries, various compounds can be used as additives and auxiliaries depending on the application. 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.

  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 miscibility with the premix solution, a surfactant that is also used in the premix solution may be used in combination as a compatibilizer. 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 is produced by mixing and curing a polyol, water, a catalyst, a surfactant, other auxiliaries and a polyisocyanate. In practice, the polyisocyanate is a polyisocyanate liquid, a polyol. As a premix liquid, water, catalyst, surfactant, and other auxiliary agents are mixed in advance in a polyisocyanate liquid and / or premix liquid, and the two liquids are mixed using a device described later, and foamed. It is a method of curing. In addition, it is preferable to mix water, a catalyst, and a surfactant as a foaming agent into the premix solution, but in some cases, it is not mixed into the polyisocyanate solution or the respective components are not mixed until just before the urethanization reaction. In some cases, three or more kinds of raw material liquids are handled.

  The rigid polyurethane foam obtained by the present invention has a urethane bond, a urea bond, an isocyanurate bond, and the like. 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 [(number of moles of isocyanate group) / (number of moles of all active hydrogen groups excluding water) × 100] is usually 50 to 500, preferably 60 to 450, more preferably 70 to 400. . When the isocyanate index is less than 50, the obtained rigid polyurethane foam may not have sufficient flame retardancy and opportunity strength, and when it exceeds 500, the resulting rigid polyurethane foam becomes brittle and has an adhesive strength. Tend to decrease.

The density of the rigid polyurethane foam of the present invention is expressed as a core density when a free foam is prepared by a known method, and is 10 to 70 kg / m ³ , preferably 15 to 65 kg / m ³ , more preferably 20 to 60 kg / m is ^3. 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.

  In producing the rigid polyurethane foam, any apparatus can be used as long as the premix liquid and the polyisocyanate liquid can be uniformly mixed. 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 a premix liquid and a polyisocyanate liquid is normally adjusted to 10-60 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, 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 polyester polyol]
Polyols used in the examples and comparative examples were synthesized by known methods using polyester polyols in the presence or absence of lignin-based substances, and as polyols 1 to 9, raw material composition, types of lignin-based substances, addition amounts and additions The method, hydroxyl value, and viscosity (25 ° C.) are shown in Table 1. The lignin-based material is added by reacting with a carboxylic acid component and an alcohol component at the time of polyester polyol production, and added separately after polyester polyol production and dissolved by mixing at 120 ° C. for 60 minutes. Was "attached". The hydroxyl value and viscosity were analyzed according to JIS K1557 (2007).

なお、「表１」中の略号の意味は以下のとおりである
ＤＥＧ ： ジエチレングリコール
ＴＥＧ ： トリエチレングリコール
ＰＥＧ４００ ： ポリエチレングリコール（数平均分子量４００）
１４ＢＤ ： １，４−ブタンジオール
ＬＳ ： リグニンスルホン酸
ＫＬ ： クラフトリグニン
ＡＬ ： アルカリリグニン
ＨＬ ： 酸加水分解リグニン

The meanings of the abbreviations in “Table 1” are as follows: DEG: diethylene glycol TEG: triethylene glycol PEG400: polyethylene glycol (number average molecular weight 400)
14BD: 1,4-butanediol LS: Lignin sulfonic acid KL: Kraft lignin AL: Alkaline lignin HL: Acid-hydrolyzed lignin

In Polyol-9, a lignin-based substance was added to a polyester polyol composed of adipic acid and 1,4-butanediol and stirring was continued at 80 ° C., but it was observed that the lignin-based substance dissolved and the polyol became uniform. It was not used in subsequent tests.

  Separately, Kraft lignin was mixed with diethylene glycol so as to be a 10 w% solution, and dissolved in 120 ° C. for 30 minutes, and used as polyol-10.

[Premix solution preparation]
Premix liquids 1 to 11 were prepared with the raw materials and blends shown in Table 2. In addition, the compounding ratio in a table | surface was shown by weight% when all the polyols are 100 weight%. (Examples 1-5 and Comparative Examples 1-6)

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

[Production of rigid polyurethane foam]
The rigid polyurethane foam was produced and evaluated by the following method. Table 4 shows the evaluation results as Examples 1 to 5 and Comparative Examples 1 to 6.

<Manufacturing method>
After mixing the polyisocyanate liquid and the premix liquid described in Table 2, it was poured into an injection box and subjected to free foaming to produce a rigid polyurethane foam (free foam). In addition, polymeric MDI ("Millionate MR-200" manufactured by Nippon Polyurethane Industry Co., Ltd.) was used as the polyisocyanate liquid, and the isocyanate index during mixing is shown in Table 4.

<Foaming conditions>
Room temperature: 23-25 ° C
Liquid temperature: 20 ° C. (excluding Example 3 and Comparative Examples 3 and 4) 15 ° C. (Example 3 and Comparative Examples 3 and 4)
Stirring: 3000 rpm × 3-7 seconds Injection box: Wooden (200 mm × 200 mm × 200 mm) Upper open demolding time: 30 minutes after mixing

  The obtained rigid polyurethane foam was evaluated by the following method, and the results are shown in Table 4.

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

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

○: It did not penetrate for 60 seconds or more.
Δ: Penetrated in 30 seconds to less than 60 seconds.
X: Penetrated in less than 30 seconds.

(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 central part into 5x10x3cm 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: 10 N / 5 cm or more.
Δ: 5 N / 5 cm or more.
X: Less than 5 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 Examples and Comparative Examples 2, 4, and 5:
Compared to the examples using the polyester polyol composition containing the lignin-based material of the present invention, Comparative Examples 2, 4, and 5 using the polyester polyol composition not containing the lignin-based material have poor flame retardancy and mechanical strength. Is slightly lower.

(2) Comparison results between Examples and Comparative Examples 1, 2, 4, and 5:
The polyester polyol composition containing the lignin-based material of the present invention was compared with Examples in which only 20% by weight of the total polyol was used, and Comparative Example 1 in which only 10% by weight was used and Comparative Examples 2, 4 in which no polyester was used. No. 5 has poor flame retardancy and slightly low mechanical strength.

(3) Comparison results between Example and Comparative Examples 3 and 6:
Only succinic acid, which is an aliphatic carboxylic acid component, is used in comparison with Examples using a polyester polyol composition containing a lignin-based material using an aromatic carboxylic acid component of the present invention and polyethylene glycol having a number average molecular weight of 100 to 600. Comparative Example 3 using Polyol-6 using Polyethylene and Comparative Example 6 using diethylene glycol instead of polyester polyol have poor flame retardancy and low mechanical strength even if they contain a lignin-based substance.

Claims (9)

  A polyester polyol composition containing 1 to 60% by weight of a lignin-based substance, wherein the polyester polyol contains a carboxylic acid component containing an aromatic carboxylic acid and a polyethylene glycol having a molecular weight or number average molecular weight of 100 to 600. A polyester polyol composition obtained by an esterification reaction with a component.   The aromatic carboxylic acid is at least one or more selected from the group consisting of phthalic acid, terephthalic acid and isophthalic acid, and the amount used is 20 mol% or more of the total carboxylic acid component. A polyester polyol composition as described in 1.   The polyester polyol composition according to claim 1 or 2, wherein 80 to 20 mol% of succinic acid and / or adipic acid is further used as the carboxylic acid component.   The polyester polyol composition according to any one of claims 1 to 3, wherein the entire composition has a hydroxyl value of 30 to 500 mgKOH / g and a viscosity at 25 ° C of 30000 mPa · s or less.   The lignin-based substance is at least one selected from the group consisting of kraft lignin, acid-hydrolyzed lignin, solvolytic lignin, alkaline lignin and lignin sulfonic acid, or any one of two or more kinds. The polyester polyol composition according to one item.  The polyester polyol composition according to any one of claims 1 to 5, wherein the esterification reaction is performed in the presence of a lignin-based substance.   In the manufacturing method of the rigid polyurethane foam which uses a polyol, a foaming agent, a catalyst, surfactant, and polyisocyanate at least, the polyester polyol composition as described in any one of Claims 1-6 is 20 weight of all the polyols as a polyol. % Of rigid polyurethane foam to be used.   The method for producing a rigid polyurethane foam according to claim 7, wherein water is used as a foaming agent.   The method for producing a rigid polyurethane foam according to claim 7 or 8, wherein the isocyanate index is 50 to 500.