JP5709045B2 - Method for producing polyurethane foam - Google Patents

Description

  The present invention relates to a method for producing a polyurethane foam, and more particularly to a method for producing a rigid polyurethane foam having excellent dimensional stability.

  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.

  Environmental problems such as ozone depletion and global warming have been taken up, and no foaming agents such as chlorofluorocarbons or alternative chlorofluorocarbons are used. Carbon dioxide generated by the reaction of water and polyisocyanate is used as the foaming gas. Water foaming technology is drawing attention. This method makes it possible to reduce the amount of foaming agent used or not at all. However, the speed of the carbon dioxide gas diffusing to the outside through the closed cell cell membrane of the rigid polyurethane foam is faster than the speed at which air permeates, so that the foam cell is in a reduced pressure state, and as a result, it is easy to shrink, That is, the dimensional stability tends to deteriorate. Furthermore, compared to the conventional formulations using foaming agents, the brittleness of the resulting foam deteriorates due to the influence of urea groups generated by the reaction of water and polyisocyanate, and the adhesive strength with the adherend member is reduced. There is also a drawback that it easily occurs. These drawbacks are particularly noticeable when a large amount of water is used to reduce the density of the rigid polyurethane foam, which is an obstacle to popularizing the rigid polyurethane foam by water foaming.

  As a method to improve the dimensional stability of rigid polyurethane foam using water as a foaming agent, it is possible to eliminate the pressure difference between the inside and outside of the foam by making foam cells, which are normally closed cells, partially or entirely open cells. It is valid. For example, there is a method (Patent Document 1) in which a long-chain polyether polyol having a molecular weight of about 600 to 2000 per hydroxyl group and a polyether polyol having a molecular weight of less than about 600 per hydroxyl group are used in a polyol. However, long-chain polyether polyols used for such applications generally have poor compatibility with water, polyester polyols, and the like, causing problems in the uniformity of the premix solution. If the premix solution is non-uniform, the long-term storage stability is deteriorated, and the foam bubbles obtained are non-uniform, resulting in cell roughness and poor adhesion.

  In order to solve the problem of the uniformity of the premix solution, the present inventors have prepared a polyester polyol comprising an aliphatic polycarboxylic acid having 4 to 8 carbon atoms and dipropylene glycol, or an aliphatic having 4 to 8 carbon atoms. The method of using the polyester polyol which consists of polyhydric carboxylic acid and / or C8-C10 aromatic polyhydric carboxylic acid and dipropylene glycol and tripropylene glycol as a compatibilizer of a premix liquid was proposed. (Patent Documents 3 and 4) Although these compatibilizers have solved the problems related to the uniformity of the premix liquid, on the other hand, the necessary amount of the polyester polyol used as the compatibilizer is large and it is difficult to blend other components There was a bug.

  On the other hand, the present inventors are polyester polyols obtained by esterifying a polycarboxylic acid and an alcohol as a polyester polyol having good compatibility with a foaming agent such as an HFC-based foaming agent. Polyester polyol using 2 to 40% by weight of at least one selected from the group consisting of 1-hydroxy-2-acetoxybutane, 1-acetoxy-2-hydroxybutane and 1,2-diacetoxybutane Although proposed, the contribution to the homogeneity of the premix solution using the long-chain polyether polyol has not been studied at all. (Patent Document 5)

JP-A-6-25375 JP 61-153478 A JP 2009-270079 A JP 2010-189455 A Japanese Patent No. 4512491

  The present invention has been made in view of the above circumstances, and its purpose is to provide a highly uniform premix solution for polyurethane foam and a method for producing a rigid polyurethane foam excellent in dimensional stability using the same. Is to provide.

  As a result of intensive studies by the present inventors, the knowledge that the above-mentioned object can be easily achieved by using a polyester polyol and a polyether polyol having specific structural characteristics as a raw material polyol has been obtained. Thus, the present invention has been completed.

That is, the gist of the present invention is at least a polyisocyanate, a polyol, a foaming agent, a catalyst, and a polyurethane foam production method using a surfactant as a raw material, together with the polyols (A) and (B) described below as a polyol (C) and / or (D) is used, and the ratio of (A) and (B) in the total polyol is 1 to 30% by weight, respectively.
(1) A polyester polyol obtained by an esterification reaction of an alcohol component and a carboxylic acid component, and 1,2-butanediol (hereinafter abbreviated as 1,2-BG) as an alcohol component, and 1-hydroxy-2- Acetoxybutane (hereinafter abbreviated as 1,2-HAB), 1-acetoxy-2-hydroxybutane (hereinafter abbreviated as 1,2-AHB), and 1,2-diacetoxybutane (hereinafter abbreviated as 1,2-DAB) Polyester polyol: polyol (polyol), which is a mixture containing at least one selected from the group consisting of (abbreviation) , and whose mixture contains 60-98% by weight of 1,2-butanediol in the mixture. A).
(2) Polyether polyol: polyol (B) having an average functional group number of 2.0 to 3.0 and a hydroxyl value of 10 to 100 mgKOH / g.
(3) A polyester polyol obtained by an esterification reaction of an alcohol component and a carboxylic acid component (excluding those corresponding to the polyol (A)), from orthophthalic acid, isophthalic acid, and terephthalic acid as the carboxylic acid component . Polyester polyol using at least one selected from the group consisting of: Polyol (C).
(4) Polyether polyol: polyol (D) having an average functional group number of 3.0 to 8.0 and a hydroxyl value of 150 to 800 mgKOH / g.

  ADVANTAGE OF THE INVENTION According to this invention, provision of the highly uniform premix liquid for polyurethane foams and the manufacturing method of the rigid polyurethane foam excellent in the dimensional stability using this can be provided.

  Hereinafter, the present invention will be described in detail.

The polyurethane foam production method of the present invention uses (C) and / or (D) together with the polyols (A) and (B) described below as the polyol.
(1) A polyester polyol obtained by an esterification reaction of an alcohol component and a carboxylic acid component, from 1,2-BG, 1,2-HAB, 1,2-AHB and 1,2-DAB as the alcohol component. Polyester polyol using a mixture containing at least one selected from the group consisting of: Polyol (A).
(2) Polyether polyol: polyol (B) having an average functional group number of 2.0 to 3.0 and a hydroxyl value of 10 to 100 mgKOH / g.
(3) Polyester polyol obtained by esterification reaction of an alcohol component and a carboxylic acid component, and using at least one selected from the group consisting of orthophthalic acid, isophthalic acid and terephthalic acid as a carboxylic acid component: Polyol (polyol) C).
(4) Polyether polyol: polyol (D) having an average functional group number of 3.0 to 8.0 and a hydroxyl value of 150 to 800 mgKOH / g.

  The polyol (A) of the present invention is made from a mixture containing 1,2-BG and at least one selected from the group consisting of 1,2-HAB, 1,2-AHB and 1,2-DAB as a raw material. Polyester polyol.

  That is, the polyol (A) of the present invention is a mixture containing 1,2-BG and at least one selected from the group consisting of 1,2-HAB, 1,2-AHB and 1,2-DAB. The content of 1,2-BG in the mixture is normally 60 to 98% by weight, preferably 65 to 95% by weight, more preferably 70 to 90% by weight. It is. When the content of 1,2-BG is less than 60% by weight, the effect of improving the uniformity of the premix solution is reduced, and when it exceeds 98% by weight, the viscosity of the resulting polyester polyol is increased and handling is difficult. become. The content of at least one component selected from the group consisting of 1,2-HAB, 1,2-AHB and 1,2-DAB in the mixture is usually 2 to 40% by weight, preferably 5 to 5% by weight. It is 35% by weight, more preferably 10 to 30% by weight, and the ratio of each component of 1,2-HAB, 1,2-AHB and 1,2-DAB is not particularly limited as long as it is within this range.

  As such a mixture, mainly 1,3-butadiene and acetic acid are subjected to an acetoxylation reaction in the presence of molecular oxygen and a palladium-based catalyst, and reaction products such as diacetoxybutenes and monoacetoxybutenes obtained are produced. The product is hydrogenated in the presence of a noble metal catalyst, and then the resulting reaction products such as diacetoxybutanes and monoacetoxybutanes are hydrolyzed in the presence of a solid acid catalyst to distill off acetic acid and water. It can be obtained by separating by distillation. That is, it can be obtained as a byproduct when 1,3-butadiene and acetic acid are reacted to produce 1,4-butanediol. When using this by-product, in addition to at least one selected from the group consisting of 1,2-BG and 1,2-HAB, 1,2-AHB and 1,2-DAB, acetic acid, water, 1, A small amount of 4-butanediol, 1,4-butanediol acetate, and the like may be contained.

  Examples of alcohol components that can be used in addition to the above include monohydric 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. Two or more of these monohydric alcohols and polyhydric alcohols may be used in combination.

  In order to improve the uniformity of the premix solution, among these alcohol components, at least selected from the group consisting of 1,2-BG and 1,2-HAB, 1,2-AHB and 1,2-DAB. The mixture containing 1 type is normally used 70 weight% or more of the total alcohol component, Preferably it is 80 weight% or more, More preferably, it is used 90 weight% or more.

  Examples of the carboxylic acid component that is a raw material of the polyol (A) of the present invention include acetic acid, benzoic acid, orthophthalic acid, terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, maleic acid, fumaric acid, trimellitic acid, An aromatic or aliphatic carboxylic acid such as pyromellitic acid is used. Two or more of these aromatic or aliphatic carboxylic acids can be used in combination, but from the viewpoint of reducing the viscosity of the resulting polyester polyol, it is preferable to use an aliphatic carboxylic acid, and succinic acid and / or More preferably, adipic acid is used.

  When using succinic acid and / or adipic acid, the amount used is preferably 70% by weight or more, more preferably 80% by weight or more of the total carboxylic acid component.

  The hydroxyl value of the polyol (A) of the present invention is usually 30 to 300 mgKOH / g, preferably 35 to 290 mgKOH / g, more preferably 40 to 280 mgKOH / g. When the hydroxyl value is less than 30 mgKOH / g, the viscosity increases and handling becomes difficult, and when it exceeds 300 mgKOH / g, the brittleness of the resulting polyurethane foam may deteriorate.

  The viscosity of the polyol (A) of the present invention at 25 ° C. is usually 2000 mPa · s or less, preferably 1800 mPa · s or less, more preferably 1600 mPa · s or less. When the viscosity exceeds 2000 mPa · s, the viscosity of the premix liquid increases and handling becomes difficult. Although there is no particular lower limit, it is 100 mPa · s, for example, considering the preferred range of the hydroxyl value.

  Usually, an esterification catalyst is used for manufacture of a polyol (A). In general, an acid catalyst is often used. Examples of Lewis acids include orthotitanate such as tetraisopropyl titanate and tetra-n-butyl titanate; tin compounds such as diethyltin oxide and dibutyltin oxide; zinc oxide And metal compounds such as In addition to Lewis acid, Bronsted acid such as sulfuric acid, paratoluenesulfonic acid, methanesulfonic acid and the like may be used. Among these, orthotitanate is preferable from the viewpoint that the residual catalyst does not adversely affect the urethanization reaction.

  The amount of the esterification catalyst used is usually 0.1% by weight or less, preferably 0.07% by weight or less, and more preferably 0.05% by weight or less as a ratio to the polyester polyol obtained. Depending on the use of the rigid polyurethane foam, the reaction may be performed without using an esterification catalyst, or a deactivation treatment may be performed after the reaction, or it may be removed by purification or the like.

  In the production of the polyol (A), the end point of the esterification reaction is usually determined by the amount of unreacted carboxyl groups of the carboxylic acid used. The presence of an acid content in the premix solution may lower the reactivity of urethanization by the action of an amine catalyst or the like, or may affect the storage stability of the premix solution. Therefore, the amount of unreacted carboxylic acid, that is, the acid value is preferably as low as possible. The acid value of the polyester polyol (A) is usually 3 mgKOH / g or less, preferably 2 mgKOH / g or less, more preferably 1 mgKOH / g or less. Although there is no particular lower limit, it is 0.1 mgKOH / g in consideration of reaction conditions and reaction time.

  As production conditions for the polyol (A), generally known reaction equipment and reaction conditions can be applied.

  The polyol (B) of the present invention is a polyether polyol having an average functional group number of 2.0 to 3.0 and a hydroxyl value of 10 to 100 mgKOH / g. Specific examples include polyoxyalkylene glycols and alkylene oxide adducts of polyhydric alcohols. Polyoxyalkylene glycol can be obtained by ring-opening polymerization of alkylene oxides such as ethylene oxide, propylene oxide, 1,2-butylene oxide, alone or in combination. An alkylene oxide adduct of a polyhydric alcohol can be obtained by adding the above alkylene oxide to alcohols such as trimethylolpropane and glycerin. Such a polyol (B) is widely commercially available and can be easily obtained, but it is preferable to use an ethylene oxide and / or propylene oxide adduct of glycerin.

  In these polyols (B), for example, the ethylene oxide content (polyoxyethylene units) in the polyol obtained as a polymer or adduct of ethylene oxide or propylene oxide is usually 70% by weight or less, preferably 60% by weight or less, More preferably, it is 50% by weight or less, and the content of propylene oxide (polyoxypropylene unit) is usually 30% by weight or more, preferably 40% by weight or more, and more preferably 50% by weight or more. When the ethylene oxide content exceeds 70% by weight, the uniformity of the premix is often good without using the polyol (A) of the present invention, but the effect of improving the dimensional stability is reduced. It is preferable to use an oxide in combination, and a polymer or an adduct of only propylene oxide may be used.

  The average functional group number of the polyol (B) is usually 2.0 to 3.0, and those having an average functional group number of 2.0 or 3.0 can be used alone or as a mixture thereof. When the average functional group number is less than 2.0, physical properties such as mechanical strength and flame retardancy of the obtained rigid polyurethane foam are deteriorated. When the average number of functional groups is larger than 3.0, the effect of improving the dimensional stability becomes small.

  The hydroxyl value of a polyol (B) is 10-100 mgKOH / g normally, Preferably it is 20-90 mgKOH / g, More preferably, it is 30-80 mgKOH / g. When the hydroxyl value is less than 10 mgKOH / g, the system liquid tends to be non-uniform, and when it is greater than 100 mgKOH / g, the effect of improving dimensional stability is reduced. The hydroxyl group may be either primary or secondary, but secondary tends to increase the effect of improving dimensional stability.

The polyol (C) of the present invention is a polyester polyol obtained by an esterification reaction of an alcohol component and a carboxylic acid component (excluding those corresponding to the polyol (A)), wherein orthophthalic acid, At least one selected from the group consisting of isophthalic acid and terephthalic acid is used.

  As the carboxylic acid component that is a raw material of the polyol (C), it is essential to use at least one selected from the group consisting of orthophthalic acid, isophthalic acid and terephthalic acid, and it is preferable to use terephthalic acid and / or isophthalic acid. . Besides them, aliphatic carboxylic acid and / or aromatic carboxylic acid can be used together, and as aliphatic carboxylic acid, acetic acid, succinic acid, adipic acid, sebacic acid, maleic acid, fumaric acid and the like can be mentioned, Examples of the aromatic carboxylic acid include benzoic acid, trimellitic acid, pyromellitic acid and the like.

  From the viewpoint of imparting flame retardancy to the resulting polyurethane foam, in the polyol (C), at least one selected from the group of orthophthalic acid, terephthalic acid and isophthalic acid is usually 20% by weight or more of the total carboxylic acid component, preferably Is used at 25% by weight or more, more preferably 30% by weight or more. Further, from the viewpoint of reducing the viscosity of the polyester polyol and improving the brittleness of the polyurethane foam, it is preferable to further use an aliphatic carboxylic acid, and more preferably to use succinic acid and / or adipic acid.

  Examples of the alcohol component that is a raw material of the polyol (C) include aliphatic dihydric alcohols such as ethylene glycol, propanediol, and butanediol, oxyalkylene glycols such as diethylene glycol, triethylene glycol, and dipropylene glycol, polyethylene glycol, and polypropylene. And polyoxyalkylene glycols such as glycol and polytetramethylene ether glycol. In addition, trivalent or higher alcohols such as glycerin and trimethylolpropane may be used, or two or more alcohols may be used in combination. Among these, oxyalkylene glycol or polyoxyalkylene glycol is preferable, and oxyalkylene glycol having a number average molecular weight of 100 to 1000 or polyoxyalkylene glycol having a number average molecular weight of 100 to 1000 is more preferably used.

  The hydroxyl value of the polyol (C) is usually 50 to 300 mgKOH / g, preferably 60 to 290 mgKOH / g, more preferably 70 to 280 mgKOH / g. When the hydroxyl value is less than 50 mgKOH / g, the viscosity increases and handling becomes difficult, and when it exceeds 300 mgKOH / g, the brittleness of the polyurethane foam deteriorates, which is not preferable.

  The viscosity at 25 ° C. of the polyol (C) of the present invention is usually 2000 mPa · s or less, preferably 1800 mPa · s or less, more preferably 1600 mPa · s or less. When the viscosity exceeds 2000 mPa · s, the viscosity of the premix liquid increases and handling becomes difficult. Although there is no particular lower limit, it is 100 mPa · s considering the preferable range of the hydroxyl value. Such a polyol (C) is widely commercially available and can be easily obtained. Particularly preferred is a hydroxyl value of 50 to 300 mgKOH / g and a viscosity at 25 ° C. of 500 to It is a 2000 mPa · s polyester polyol.

  The polyol (D) of the present invention is a polyether polyol having an average functional group number of 3.0 to 8.0 and a hydroxyl value of 150 to 800 mgKOH / g. Specifically, polymers such as ethylene oxide, propylene oxide, alkylene oxide such as 1,2-butylene oxide, or tetrahydrofuran alone or in combination; alcohols such as sucrose, sorbitol, erythritol, pentaerythritol, trimethylolpropane, glycerin, etc. And adducts of the above alkylene oxides, aliphatic amines such as ethylene diamine, aromatic amines such as toluene diamine and adducts of the above alkylene oxides. In addition, Mannich modified polyol, polymer polyol, etc. are mentioned. These polyols (D) are widely commercially available and can be easily obtained.

  The function of each of the polyols (A) to (D) is as follows. That is, the polyether polyol (B) has poor compatibility with the polyester polyol (C), the polyether polyol (D), water as a foaming agent, and the like, and is not uniform when mixed into a premix solution. Become cloudy and separate. On the other hand, the polyester polyol (A) is compatible with any of the above (B), (C), and (D) and has a function of improving the uniformity of the premix solution. In other words, with respect to the commonly used polyester polyol (C) and / or polyether polyol (D), the polyether polyol (B) functions as a so-called cell communicating agent, and the polyester polyol (A) Acts as a solubilizer.

  The method for producing a polyurethane foam of the present invention uses polyol (A) and polyol (B) as the polyol, and further uses either or both of polyol (C) and polyol (D). Here, the usage-amount of the polyol (A) and polyol (B) in all the polyols is 1-30 weight% normally respectively, Preferably it is 2-27 weight%, More preferably, it is 3-25 weight%. When the content of the polyol (A) is less than 1% by weight, the effect of homogenizing the system liquid cannot be obtained, and even when the content exceeds 30% by weight, the effect reaches a peak. When the content of the polyol (B) is less than 1% by weight, the dimensional stability is deteriorated, and when it exceeds 30% by weight, the premix solution tends to be non-uniform.

  The ratio of polyol (C) and / or polyol (D) is determined by the content of polyol (A) and polyol (B). When it is intended to impart flame retardancy to the polyurethane foam, the content of the polyol (C) in the total polyol is usually 10 to 70% by weight, preferably 15 to 65% by weight, more preferably 20 to 60% by weight. %. When the content of the polyol (C) is less than 10% by weight, the effect of improving the flame retardancy is not recognized, and when it exceeds 70% by weight, the adhesiveness may be deteriorated. There is no restriction | limiting in particular in the usage-amount of polyol (D), It can be set as the remainder of the usage-amount of polyol (A) and (B) or polyol (A), (B), and (C).

  In addition to the above polyols (A) to (D), alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and glycerine; alkanolamines such as diethanolamine and triethanolamine; compounds having two or more active hydrogens in one molecule Etc. can be used together.

  Examples of the foaming agent include a foaming agent having an ozone depletion coefficient of 0, for example, HFC foaming agents such as water, HFC-245fa, and HFC-365mfc, HC foaming agents such as pentane and cyclopentane, HFO-1234ze, and HFO-1234yf. HFO foaming agents such as. 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. If only water is used, it is usually 1 to 25 parts by weight, preferably 2 to 23 parts by weight with respect to 100 parts by weight of the polyol. More preferably, it is 3 to 20 parts by weight. When it is less than 1 part by weight, the density of the resulting polyurethane foam becomes too high to be practical, and when it exceeds 25 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 catalysts such as triethylenediamine and N, N-tetramethylhexanediamine, quaternary ammonium salts, potassium compounds such as potassium octylate, tin compounds 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 used in the present invention may be any of a nonionic surfactant, an anionic surfactant, or a cationic surfactant, but a nonionic surfactant is preferable, and a silicone surfactant is particularly 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.

  As other auxiliaries, various compounds can be used as additives and auxiliaries depending on applications. 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. Of these modified products, carbodiimide modified products are those 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 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. 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 described above are not particularly limited, and are used for the purpose of improving physical properties and operability in ordinary resins. I do not care.

  The isocyanate index in the present invention is [(number of moles of all isocyanate groups) / (number of moles of all active hydrogen groups) × 100], usually 50 to 200, preferably 60 to 190, more preferably 70 to 180. is there. When the isocyanate index is less than 50, the obtained polyurethane foam may not have sufficient strength. When it exceeds 200, the resulting polyurethane foam becomes brittle and tends to have low adhesive strength.

The density of the polyurethane foam obtained in the present invention is expressed by the core density of the free foam, and is 10 to 50 kg / m ³ , preferably 15 to 45 kg / m ³ , more preferably 20 to 40 kg / m 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 50 kg / m ³ , the cost becomes high.

  The closed cell ratio of the polyurethane foam in the present invention is 70% or less. Usually, in order to reduce the closed cell ratio, that is, to make the bubbles continuous, a bubble communicating agent is required. In the present invention, some or all of the bubbles can be made continuous by a combination of the polyol (A) and the polyol (B). The preferred closed cell ratio of the polyurethane foam in the present invention is 65% or less, more preferably 60% or less. When the closed cell ratio exceeds 70%, the dimensional stability tends to deteriorate. The lower limit of the closed cell ratio is not particularly limited, and all of the bubbles are continuous, that is, the closed cell ratio may be 0%. However, the mechanical strength tends to decrease, so, for example, it is limited to 20% or more. Is good.

  Polyurethane foam is produced by mixing polyisocyanate, polyol, foaming agent, catalyst, surfactant, other auxiliaries and polyisocyanate, and curing the foam by practical use. , Polyol as B liquid (premix liquid), water, catalyst, surfactant and other auxiliaries are mixed in advance with B liquid as appropriate, and the two liquids are mixed using the apparatus described later, foamed, It is a method of curing. 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. Sometimes handled as a raw material liquid.

  In producing the polyurethane foam, 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 obtained by 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.

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

<Synthesis of polyol (A)>
The polyol (A) used in the examples and comparative examples and the polyol of the reference example were synthesized by a known method, and the raw material composition, acid value, hydroxyl value, viscosity (25 ° C.) of polyols 1, 2 and polyols 3, 4 respectively. Are shown in Table 1.

<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 .

  At least one selected from the group consisting of 1,2-butanediol, 1-hydroxy-2-acetoxybutane, 1-acetoxy-2-hydroxybutane and 1,2-diacetoxybutane, which is a raw material for the polyol (A) As the mixture containing seeds, crude 1,2-butanediol (hereinafter abbreviated as C12BG) manufactured by Mitsubishi Chemical Corporation was used, and the respective contents described in the analysis table are shown in Table 2.

＜原料の略称＞
ＡＤＡ ： アジピン酸（和光純薬工業株式会社製 試薬特級）
Ｃ１２ＢＧ ： 上記に記載の混合物
１２ＢＧ ： １，２−ブタンジオール（和光純薬工業株式会社製 試薬特級）

<Abbreviations for raw materials>
ADA: Adipic acid (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd.)
C12BG: mixture 12BG described above: 1,2-butanediol (reagent special grade manufactured by Wako Pure Chemical Industries, Ltd.)

  A premix solution was prepared from the raw materials and blends shown in Table 4. Further, the uniformity of the premix solution at that time was visually observed and evaluated according to the following criteria. “◯”: uniform, “×”: cloudy or separated. In the formulation examples of Table 4, the raw materials shown in Table 5 were used.

  After mixing the polyisocyanate liquid and the premix liquid described in Table 4 under the foaming conditions shown in Table 3, the mixture was poured into an injection box for free foaming to produce a polyurethane foam. In addition, the polyisocyanate liquid described in Table 5 was used.

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

(1) Reactivity:
CT (cream time): After mixing the polyisocyanate liquid and the premix liquid, the time until the foaming height reached 1% was measured.
GT (gel time): After mixing the polyisocyanate and the premix solution, the time until starting to draw the yarn with a stylus was measured.
RT (rise time): After mixing the polyisocyanate and the premix solution, the time until the foaming height reached 95% was measured.

(2) Core density:
It measured based on JIS A9511 (2003).

(3) Compressive strength:
In accordance with JIS A9511 (2003), measurements were made in the parallel direction (indicated by the symbol “//” in Table 3) and the vertical direction (indicated by the symbol “⊥” in Table 3). The parallel direction means a direction parallel to the foaming direction (that is, the longitudinal direction) in free foaming by the top-opening injection box, and the vertical direction is a direction perpendicular to the foaming direction (that is, the lateral direction). ) (Same below).

(4) Closed cell ratio:
Measured according to ASTM D 2856.

(5) Dimensional stability:
The dimensional change rate (parallel direction, vertical direction) after 24 hours at −20 ° C. of the sample whose core density was measured was measured and evaluated according to the following criteria.

◎: Less than -1% for both parallel and vertical ○: -1% or more for both parallel and vertical, and less than -3% ×: Either parallel or vertical is -3% or more

(6) Adhesiveness:
Create a free form using kraft paper surface material, cut out the central part to 5x10x3cm, create a test piece, peel off part of the length direction end of kraft paper surface material, and then pull in the thickness direction with a tensile tester The peel strength (N / 5 cm) was measured and evaluated according to the following criteria.

◎: 13N / 5cm or more ○: 10N / 5cm or more, less than 13N / 5cm ×: Less than 10N / 5cm

(7) Brittleness:
The surface and bottom of the rigid polyurethane foam were qualitatively observed by palpation and evaluated according to the following criteria.

A: There is no brittleness.
○: Almost no brittleness.
X: There is some brittleness.

  The effect of the polyol (A) of the present invention as a compatibilizer was compared with conventional polyols (described in Patent Documents 3 and 4).

<Synthesis of polyol to be compared>
A polyol was synthesized in the same manner as polyol 2 described in Patent Document 3 and polyol 1 described in Patent Document 4, and the raw material composition, acid value, hydroxyl value, and viscosity (25 ° C.) were represented as polyols-9 and 10. This is shown in FIG.

＜原料の略称＞
ＳＣＡ ： コハク酸（和光純薬工業株式会社製 試薬特級）
ＤＰＧ ： ジプロピレングリコール（和光純薬株式会社性 試薬特級）
ＨＰＧ ： ヘビープロピレングリコール（Ｓｈｅｌｌ Ｅａｓｔｅｒｎ Ｐｅｔｒｏｌｅｕｍ社製）
ＨＰＧの組成：ジプロピレングリコール ３０ｍｏｌ％
トリプロピレングリコール ６６ｍｏｌ％
テトラプロピレングリコール ４ｍｏｌ％

<Abbreviations for raw materials>
SCA: Succinic acid (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd.)
DPG: Dipropylene glycol (Wako Pure Chemical Industries, Ltd., special reagent grade)
HPG: Heavy propylene glycol (manufactured by Shell Eastern Petroleum)
HPG composition: Dipropylene glycol 30 mol%
Tripropylene glycol 66mol%
Tetrapropylene glycol 4mol%

  As the premix liquid excluding the component corresponding to the polyol (A) acting as a compatibilizing agent, premix liquids 1 and 2 were prepared by mixing the raw materials and blends shown in Table 7. The polyol-1,2 and polyol-9,10 previously synthesized as a compatibilizer were added thereto, and the uniformity of the premix at that time was visually observed and evaluated according to the following criteria. “◯”: uniform, “×”: cloudy or separated. In the formulation examples of Table 7, the raw materials shown in Tables 5 and 8 were used, and the results are shown in Tables 9 and 10.

  From the above results, the following is mainly clear.

(1) Comparison results between Synthesis Examples 1 and 2 and Synthesis Example 3 (reference):
The polyols of Synthesis Examples 1 and 2 using a mixture containing 1,2-BG and at least one selected from the group consisting of 1,2-HAB, 1,2-AHB, and 1,2-DAB are low. In contrast to the viscosity, the polyol of Synthesis Example 3 (reference) using only 1,2-BG has a very high viscosity and is difficult to handle.

(2) Comparison results between Examples 1 to 3 and Comparative Examples 1 to 3:
In Examples 1 to 3 in which the polyol (A) and polyol (B) of the present invention were combined, the uniformity of the premix liquid and the dimensional stability of the polyurethane foam were good, whereas the polyol (A) of the present invention was good. In the case of Comparative Examples 1 to 3 in which either of the polyol (B) is missing, the uniformity of the premix solution or the dimensional stability of the polyurethane foam is poor.

(3) Comparative results of Examples 4-7 and Comparative Examples 4-7:
When the polyol (A) of the present invention is used as a compatibilizing agent, it is less added than when polyols-9 and 10 (synthesis examples 5 and 6) similar to those described in Patent Documents 3 and 4 are used. The amount of the premix solution can be made uniform.

Claims (8)

In the 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, together with the polyols (A) and (B) described below as the polyol, (C) and / or (D ), And the ratio of (A) and (B) in the total polyol is 1 to 30% by weight, respectively.
(1) A polyester polyol obtained by an esterification reaction of an alcohol component and a carboxylic acid component, and 1,2-butanediol, 1-hydroxy-2-acetoxybutane, and 1-acetoxy-2-hydroxybutane as alcohol components And at least one selected from the group consisting of 1,2-diacetoxybutane , and a mixture in which the content of 1,2-butanediol in the mixture is 60 to 98% by weight is used as a raw material Polyester polyol: Polyol (A).
(2) Polyether polyol: polyol (B) having an average functional group number of 2.0 to 3.0 and a hydroxyl value of 10 to 100 mgKOH / g.
(3) A polyester polyol obtained by an esterification reaction of an alcohol component and a carboxylic acid component (excluding those corresponding to the polyol (A)), from orthophthalic acid, isophthalic acid, and terephthalic acid as the carboxylic acid component . Polyester polyol using at least one selected from the group consisting of: Polyol (C).
(4) Polyether polyol: polyol (D) having an average functional group number of 3.0 to 8.0 and a hydroxyl value of 150 to 800 mgKOH / g.   The method for producing a polyurethane foam according to claim 1, wherein the polyol (B) is a polyether polyol having an ethylene oxide content of 70% by weight or less. The polyurethane according to claim 1 or 2, wherein the alcohol component which is a raw material of the polyol (C) 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. Form manufacturing method. The method for producing a polyurethane foam according to any one of claims 1 to 3 , wherein the polyol (A) has a hydroxyl value of 30 to 300 and a viscosity at 25 ° C of 2000 mPa · s or less. The method for producing a polyurethane foam according to any one of claims 1 to 4 , wherein succinic acid and / or adipic acid is used as a carboxylic acid component which is a raw material of the polyol (A). The method for producing a polyurethane foam according to any one of claims 1 to 5 , wherein only the water is used as the foaming agent, and the amount used is 1 to 25 parts by weight with respect to 100 parts by weight of the polyol. The method for producing a polyurethane foam according to any one of claims 1 to 6 , wherein the isocyanate index is 50 to 200. The method for producing a polyurethane foam according to any one of claims 1 to 7 , wherein the polyurethane foam obtained has a closed cell ratio of 70% or less.