JP2005314677A - Process for producing rigid foamed synthetic resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such problems as resin strength, heat insulating performance, adhesiveness, resistance to crack, and resistance to lateral flow in a well-balanced state, in a process for producing a rigid foam having a larger layer thickness by a spraying method, in particular by a multi-layered spraying method. <P>SOLUTION: In a process for producing a rigid foamed synthetic resin by reacting and foaming a polyol and a polyisocyanate in the presence of a foam regulator, a catalyst and a foaming agent by a spraying method, the process is characterized by using a polyol mixture containing 10-60 mass% of a polyol (A) below and 5-30 mass% of a polyol (B) below. Polyol (A): a polyether polyol produced by subjecting an alkylene oxide to ring-opening addition polymerization with an aromatic nitrogen-containing compound and having a hydroxy value of 200-500 mgKOH/g. Poyol (B): a polyether polyol produced by subjecting an alkylene oxide to ring-opening addition polymerization with a polyhydric alcohol and having 2-4 hydroxy groups and a hydroxy value of 25-200 mgKOH/g. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a rigid foam synthetic resin by a spray method. More specifically, the present invention relates to a method for producing a hard foamed synthetic resin suitable as a thick heat insulating material to be used by a spray method, particularly a multilayer spray method, used as a heat insulating material for a refrigerated warehouse or the like.

  A polyol and a polyisocyanate are reacted and foamed in the presence of a foam stabilizer, a catalyst and a foaming agent to produce a rigid foamed synthetic resin (hereinafter collectively referred to as a rigid foam) such as a rigid polyurethane foam and a rigid polyisocyanurate foam. Manufacturing is widely done. Since this rigid foam has a high degree of freedom in molding and excellent heat insulation performance, it is suitably employed as a heat insulating material for various devices or buildings.

  Of these, in the case of constructing a heat insulating material for a building that is particularly large in a refrigerated warehouse and requires high heat insulation performance, construction of a hard foam by a spray method is often employed. Here, the spray method is a method in which a raw material is fed at a high pressure, a raw material liquid is sprayed from a spray gun onto a wall surface or the like to be constructed, and foamed on the wall surface or the like to form a heat insulating material or the like. The advantage of the spray method is that a heat insulating material having a desired thickness can be constructed regardless of the shape of the wall surface or the like that is the object of construction. When particularly high heat insulation performance is required, a rigid foam is laminated to obtain a thick heat insulating material.

By the way, in recent years, from the viewpoint of environmental protection, particularly protection of the ozone layer and prevention of global warming, a change in foaming agent in the production of rigid foams has been demanded. That is, as a blowing agent to replace chlorinated fluorinated hydrocarbons such as trichlorofluoromethane (CFC-11) and 1,1-dichloro-1-fluoroethane (HCFC-141b, boiling point: 32 ° C.), which have been conventionally used, Hydrocarbon compounds such as cyclopentane, 1,1,1,2-tetrafluoroethane (HFC-134a, boiling point: −27 ° C.), 1,1,1,3,3-pentafluoropropane (HFC-245fa, boiling point) : 15 ° C), fluorinated hydrocarbons (HFC) such as 1,1,1,3,3-pentafluorobutane (HFC-365mfc, boiling point: 40 ° C), or isocyanate groups to generate carbon dioxide Water to be used has come to be used as a blowing agent. However, by changing the foaming agent, it has become clear that the raw material formulations that have been used so far have problems in terms of strength, heat insulation performance, raw material storage stability, workability, and the like. Various improved techniques have been disclosed to cope with these problems (see, for example, Patent Documents 1 to 5).
JP-T-2001-506291 JP 10-101837 A Japanese translation of PCT publication No. 2002-524630 JP 2003-201329 A JP 2003-238644 A

  However, none of the above-described techniques has provided a method that fully satisfies adhesiveness, resin strength, heat insulation performance, etc. in the production of rigid foams by the spray method. Especially when producing a rigid foam with a thick layer thickness by multilayer spraying, adhesion between the substrate and the foam layer and between the foam layer and the next foam layer, especially initial adhesion immediately after construction. Is required. When this adhesiveness is low, there arises a problem that peeling due to the weight of the foam after construction, particularly peeling between the base material and the foam layer is likely to occur.

  Also, when the foam layer is applied thickly, reaction heat based on the reaction of the raw materials tends to accumulate, and locally it may exceed 150 ° C, and cracks due to a decrease in resin strength at high temperatures may occur inside the foam layer. The problem that it is easy to generate | occur | produce and delamination easily arises. Furthermore, when trying to construct a thick foam layer, there arises a problem that a so-called transverse flow is likely to occur. Cross flow is observed when a foam is applied to a wall surface perpendicular to the ground by spraying, and the foam spreads and extends in the horizontal direction (lateral direction) from the construction part along the construction surface. This is a phenomenon that leads to poor adhesion between the base material and the foam layer, resulting in poor construction.

  The present invention has the above-mentioned problems, that is, the production of rigid foams by spraying, particularly the production of rigid foams having a thick layer thickness by multilayer spraying, such as resin strength, heat insulation performance, adhesion, suppression of cracks, suppression of lateral flow, etc. The problem is to solve the problem in a well-balanced manner.

  That is, the present invention relates to a method for producing a rigid foamed synthetic resin by reacting and foaming a polyol and a polyisocyanate by a spray method in the presence of a foam stabilizer, a catalyst and a foaming agent. There is provided a method for producing a rigid foam synthetic resin, characterized in that a polyol mixture containing 10 to 60% by mass of the whole polyol mixture and 5 to 30% by mass of the following polyol (B) in the whole polyol mixture is used. However, the polyol (A) is a polyether polyol having a hydroxyl value of 200 to 500 mgKOH / g, obtained by ring-opening addition polymerization of an alkylene oxide to an aromatic nitrogen-containing compound. The polyol (B) is a polyether polyol having a hydroxyl number of 2 to 4 and a hydroxyl value of 25 to 200 mgKOH / g, obtained by ring-opening addition polymerization of an alkylene oxide with a polyhydric alcohol.

  Moreover, it is preferable that the aromatic nitrogen-containing compound in the polyol (A) is a Mannich compound obtained by reacting phenols, aldehydes, and alkanolamines. Moreover, it is preferable that propylene oxide is used as the alkylene oxide in the polyol (B), and the proportion of propylene oxide is 50 to 95% by mass with respect to the total amount of alkylene oxide. Moreover, it is preferable to use the polyol mixture which contains the following polyol (C) 10-85 mass% of the whole polyol mixture as said polyol. However, the polyol (C) is a polyether polyol having a hydroxyl value of 250 to 800 mgKOH / g obtained by ring-opening addition polymerization of an alkylene oxide to an aliphatic nitrogen-containing compound or an alicyclic nitrogen-containing compound. It is.

  In addition, the present invention is particularly suitable when the spray method is multilayer spraying, and is effective when the closed cell ratio of the manufactured rigid foamed synthetic resin is 85% or more.

  According to the production method of the present invention, in the production of a rigid foam by a spray method, a rigid foam excellent in properties such as adhesiveness, heat insulation performance, and resin strength can be obtained. In particular, in the case of producing a rigid foam having a thick layer thickness by multilayer spraying, problems such as adhesion, suppression of cracking and suppression of lateral flow can be solved in a well-balanced manner.

  In the method for producing a rigid foam of the present invention, a rigid foamed synthetic resin is produced by reacting and foaming a polyol and a polyisocyanate by a spray method in the presence of a foam stabilizer, a catalyst and a foaming agent. The details will be described below.

(Polyol)
In this invention, as a polyol used for manufacture of a rigid foam, the polyol (A) mentioned later contains 10-60 mass% of the whole polyol mixture, and the polyol (B) mentioned later contains 5-30 mass% of the whole polyol mixture. It is characterized by using a polyol mixture. Moreover, it is preferable to use the polyol mixture which contains the polyol (C) mentioned later as 10-85 mass% of the whole polyol mixture as said polyol. That is, in this invention, a specific polyol mixture is used as a polyol used for manufacture of a rigid foam.

(Polyol (A))
In the present invention, the polyol (A) is a polyether polyol having a hydroxyl value of 200 to 500 mgKOH / g obtained by ring-opening addition polymerization of an alkylene oxide to an aromatic nitrogen-containing compound. That is, polyol (A) is a polyether polyol (polyoxyalkylene polyol) obtained by ring-opening addition polymerization of alkylene oxide using an aromatic nitrogen-containing compound as an initiator.

  Here, the aromatic nitrogen-containing compound is a compound having an aromatic ring, a nitrogen atom and an active hydrogen atom. The aromatic ring may be one having only a carbon atom such as a benzene ring as an atom constituting the ring, or one containing a hetero atom such as a pyridine ring as an atom constituting the ring. However, this aromatic ring is preferably one in which only carbon atoms are atoms constituting the ring. Examples of the compound having a nitrogen atom include a compound having an aromatic ring containing a nitrogen atom as a constituent atom, and a compound having a functional group containing a nitrogen atom such as an amino group. Of these, a compound having a functional group containing a nitrogen atom is preferred, and an amine compound is particularly preferred. However, the amine compound may be any of primary amine, secondary amine, and tertiary amine. The active hydrogen atom is a hydrogen atom to which an alkylene oxide can be subjected to ring-opening addition. That is, examples of the functional group having an active hydrogen atom include a hydroxyl group, a primary or secondary amino group, and the like.

  That is, examples of the initiator used for the production of the polyol (A) include phenylenediamine, toluenediamine, diaminodiphenylmethane, and a Mannich compound, and among them, the rigid foam from which the Mannich compound is produced is preferable in that cracks are less likely to occur. However, the Mannich compound is a compound obtained by reacting phenols, aldehydes, and alkanolamines.

  Here, examples of phenols include phenol, nonylphenol, cresol, bisphenol A, resorcinol and the like. Of these, nonylphenol is preferred because it improves the compatibility between the polyol and the polyisocyanate and improves the cell appearance. Examples of aldehydes include formaldehyde, paraformaldehyde, acetaldehyde and the like, and formaldehyde and paraformaldehyde are preferable in terms of improving the adhesiveness of the foam. Examples of the alkanolamines include monoethanolamine, diethanolamine, 1-amino-2-propanol, and aminoethylethanolamine. Of these, diethanolamine is preferable in order to balance the improvement in foam strength and the reduction in viscosity of the polyol.

  Moreover, it is preferable that the ratio of the raw material at the time of obtaining the said Mannich compound is 1-3 mol of aldehydes and 2-3 mol of alkanolamines with respect to 1 mol of phenols. If it is the said range, generation | occurrence | production of the odor at the time of manufacturing a rigid foam is suppressed, a viscosity is suppressed low, and the adhesiveness of the rigid foam obtained tends to become favorable, etc. are preferable. Among the ratios of the raw materials, the ratio of aldehydes to 1 mol of phenols is more preferably 1.2 to 2.5 mol, and further preferably 1.4 to 2.3 mol. Similarly, the ratio of alkanolamines to 1 mol of phenols is more preferably 1.2 to 2.5 mol, and further preferably 1.4 to 2.3 mol.

  Moreover, as an alkylene oxide used for manufacture of a polyol (A), ethylene oxide, propylene oxide, butylene oxide, etc. can be used. However, as this alkylene oxide, it is preferable to use propylene oxide alone or in combination of propylene oxide and ethylene oxide, and a combination of propylene oxide and ethylene oxide is more preferable. When propylene oxide and ethylene oxide are used in combination, the order of the alkylene oxide to be subjected to ring-opening addition polymerization to an aromatic nitrogen-containing compound (particularly a Mannich compound) is preferably propylene oxide first and ethylene oxide later. Moreover, 30-100 mass% is preferable with respect to the total amount of propylene oxide and ethylene oxide, and, as for the ratio of propylene oxide, 40-90 mass% is more preferable.

  By making the order of the ring-opening addition polymerization in this order, many of the hydroxyl groups of the polyol (A) become primary hydroxyl groups, the reactivity of the polyol (A) is increased, and the reactivity with the polyisocyanate is increased. It tends to be good and is preferable. Moreover, it is effective in improving the adhesiveness of the rigid foam obtained at the same time. That is, by setting the above ratio, the compatibility between the polyol (A) and the foaming agent described later is improved, the mixing property of the raw material containing isocyanate is improved, and the appearance of the resulting rigid foam is improved and the mechanical properties are improved. Is effective.

  The hydroxyl value of the polyol (A) is 200 to 500 mgKOH / g, preferably 250 to 450 mgKOH / g. When the hydroxyl value of the polyol (A) is larger than 500 mgKOH / g, there are problems that the produced rigid foam tends to be brittle and the adhesiveness of the rigid foam tends to be insufficient. When the hydroxyl value of the polyol (A) is less than 200 mgKOH / g, the resulting rigid foam tends to shrink, which is not preferable. That is, if it is in the said range, it is easy to ensure the mechanical strength of rigid foams, such as compressive strength, maintaining the mixing property of a raw material favorable, and preferable.

  Moreover, although the ratio of a polyol (A) is 10-60 mass% of the whole polyol mixture, 15-50 mass% is more preferable. If it is this range, the generation | occurrence | production of a crack and a cross flow will be suppressed, and the adhesiveness of foam layers will also improve, providing the characteristics, such as mechanical strength of a rigid foam obtained, heat resistance, and a flame retardance.

(Polyol (B))
The polyol (B) is a polyether polyol having a hydroxyl number of 2 to 4 and a hydroxyl value of 25 to 200 mgKOH / g, obtained by ring-opening addition polymerization of an alkylene oxide with a polyhydric alcohol. That is, polyol (B) is a polyether polyol obtained by ring-opening addition polymerization of alkylene oxide using a polyhydric alcohol having 2 to 4 hydroxyl groups as an initiator.

  Examples of the initiator used for producing the polyol (B) include ethylene glycol, diethylene glycol, glycerin, trimethylolpropane, 1,2,6-hexanetriol, diglycerin, pentaerythritol, and the like. It may be used. Of these, one or more selected from the group consisting of glycerin, trimethylolpropane, 1,2,6-hexanetriol, diglycerin, and pentaerythritol increase the adhesiveness of the rigid foam, particularly the initial adhesiveness. Is preferable.

  Moreover, ethylene oxide, propylene oxide, butylene oxide, etc. can be used as alkylene oxide used for manufacture of a polyol (B). However, it is preferable to use propylene oxide and ethylene oxide together as the alkylene oxide. Propylene oxide and ethylene oxide may be reacted with the initiator after mixing, or may be reacted in this order, but propylene oxide is preferred first and ethylene oxide is preferred.

  The proportion of propylene oxide is preferably 50 to 95% by mass and more preferably 60 to 90% by mass with respect to the total amount of alkylene oxide (in the case of combined use of propylene oxide and ethylene oxide, the total amount of propylene oxide and ethylene oxide). preferable. If it is the said ratio, a polyol (B) will have an appropriate reaction activity, and also the storage stability becomes favorable and is preferable. Here, the ratio of the primary hydroxyl group of the polyol (B) is preferably 60 to 100%.

  The hydroxyl value of the polyol (B) is 25 to 200 mgKOH / g, preferably 30 to 120 mgKOH / g. If the hydroxyl value of the polyol (B) is larger than 200 mgKOH / g, there are problems such that the produced rigid foam tends to be brittle and the adhesiveness of the rigid foam tends to be insufficient. When the hydroxyl value of the polyol (B) is less than 25 mgKOH / g, the resulting rigid foam tends to shrink, which is not preferable. That is, if it is in the said range, while maintaining the mixing property of a raw material favorable, the adhesive strength of a rigid foam, especially the initial adhesive strength can be made high, and it is preferable.

  Moreover, although the ratio of a polyol (B) is 5-30 mass% of the whole polyol mixture, 7-25 mass% is more preferable. Within this range, the resulting rigid foam has characteristics such as mechanical strength, and the peeling between the substrate and the foam layer is suppressed, and even when an HFC compound is used as a foaming agent, the vapor pressure of the raw material system Can be kept low.

(Polyol (C))
Polyol (C) is a polyether polyol obtained by ring-opening addition polymerization of an alkylene oxide to an aliphatic nitrogen-containing compound or alicyclic nitrogen-containing compound and having a hydroxyl value of 250 to 800 mgKOH / g. is there. That is, polyol (C) is a polyether polyol obtained by ring-opening addition polymerization of alkylene oxide using an aliphatic nitrogen-containing compound or alicyclic nitrogen-containing compound as an initiator.

  Here, the aliphatic nitrogen-containing compound or the alicyclic nitrogen-containing compound is a compound having no aromatic ring. Examples of the aliphatic nitrogen-containing compound include alkylamines such as ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, and triethylenetetraamine, and alkanolamines such as monoethanolamine and diethanolamine. Examples of the alicyclic nitrogen-containing compound include piperidines, piperazines, pyrrolidines and the like, piperazines are particularly preferred, and piperazines substituted with aminoalkyl groups are most preferred. Examples of piperidines include 1- (2-aminoethyl) piperidine. Examples of piperazines include piperazine, N-aminomethylpiperazine, 1- (2-aminoethyl) piperazine and the like. Examples of pyrrolidines include 1- (2-aminoethyl) pyrrolidine. Among these compounds, the initiator used for the production of the polyol (C) is preferably an aliphatic nitrogen-containing compound, more preferably an alkylamine, and most preferably ethylenediamine.

  Moreover, as an alkylene oxide used for manufacture of a polyol (C), ethylene oxide, propylene oxide, butylene oxide, etc. can be used. However, it is preferable to use propylene oxide alone as the alkylene oxide. In particular, when an HFC compound is used as a foaming agent, the vapor pressure of the raw material system can be kept low, which is preferable.

  The hydroxyl value of the polyol (C) is 250 to 800 mgKOH / g, preferably 280 to 770 mgKOH / g. If it is the said range, characteristics, such as resin strength and adhesiveness, can be exhibited with sufficient balance.

  The proportion of the polyol (C) is preferably 10 to 85% by mass of the entire polyol mixture, but more preferably 30 to 75% by mass. Within this range, characteristics such as mechanical strength of the resulting rigid foam can be exhibited, and even when an HFC compound is used as a foaming agent, the vapor pressure of the raw material system can be kept low.

(Other polyol (D))
In the present invention, the polyol (A) and the polyol (B) are used as the polyol used in the production of the rigid foam, and preferably the polyol (C) is used. The polyol (A) and (B) are optionally used. Or other polyols (D) other than (C) can be used. The proportion of the other polyol (D) is preferably 25% by mass or less, more preferably 10% by mass or less of the entire polyol mixture. Examples of the other polyol (D) include polyether polyol, polyester polyol, polycarbonate polyol, and acrylic polyol. Further, a polymer-dispersed polyol in which polymer fine particles are stably dispersed may be used in combination. The hydroxyl value of the other polyol (D) is preferably 300 to 600 mgKOH / g. Further, as the whole polyol mixture, the average hydroxyl value is preferably 300 to 600 mgKOH / g.

(Polyisocyanate)
In the present invention, the polyisocyanate includes aromatic, alicyclic, and aliphatic polyisocyanates having two or more isocyanate groups; a mixture of two or more of the above polyisocyanates; An isocyanate etc. are mentioned. Specific examples include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymethylene polyphenyl isocyanate (common name: crude MDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HMDI), and the like. These polyisocyanates or their prepolymer-modified products, nurate-modified products, urea-modified products, carbodiimide-modified products, and the like. Of these, crude MDI or a modified product thereof is preferred, and a modified product of crude MDI is particularly preferred.

  The viscosity of the polyisocyanate at 25 ° C. is preferably 50 to 150 mPa · s. If it is this viscosity range, shrinkage | contraction will not generate | occur | produce in the rigid foam obtained, and the operativity at the time of spraying construction by a spray method will become favorable, and it is preferable because the external appearance of the obtained rigid foam can be kept favorable.

  The amount of polyisocyanate used is represented by 100 times the number of isocyanate groups with respect to the total number of active hydrogens in the polyol and other active hydrogen compounds (usually, the value represented by 100 times is referred to as the isocyanate index), preferable. Here, in the urethane prescription which mainly uses a urethanization catalyst as a catalyst, the usage-amount of a polyisocyanate compound is an isocyanate index | exponent, 50-170 are preferable and 70-150 are more preferable. Moreover, in the isocyanurate prescription which mainly uses the catalyst which accelerates | stimulates the trimerization reaction of an isocyanate group as a catalyst, the usage-amount of a polyisocyanate compound is an isocyanate index | exponent, 120-300 are preferable and 150-270 are more preferable. In this invention, it is preferable to employ | adopt urethane prescription from viewpoints, such as adhesiveness, and the said isocyanate index has preferable 50-170.

(Foaming agent)
In the present invention, at least one selected from the group consisting of water, a fluorine-containing compound having a low boiling point, and an inert gas is used as the foaming agent. It is particularly preferable to use water and a low-boiling fluorine-containing compound in combination. The amount of water used as the blowing agent is preferably 0.5 to 10 parts by mass, particularly preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the polyol. Moreover, 5-60 mass parts is preferable with respect to 100 mass parts of polyols, and, as for the usage-amount of the low boiling point fluorine-containing compound as a foaming agent, 10-45 mass parts is more preferable.

  Examples of the low-boiling fluorine-containing compounds include HFC-134a, HFC-245fa, HFC-365mfc, 1,1,2,2-tetrafluoroethyl difluoromethyl ether (HFE-236pc), 1,1,2,2 -Tetrafluoroethyl methyl ether (HFE-254pc), 1,1,1,2,2,3,3-heptafluoropropyl methyl ether (HFE-347mcc) and the like. Among these, as the low-boiling fluorine-containing compound, it is preferable to use one or more selected from the group consisting of HFC-134a, HFC-245fa, and HFC-365mfc. Examples of the inert gas include air, nitrogen, carbon dioxide gas and the like.

  When the low-boiling fluorine-containing compound and water are used in combination, it is preferable in that it is easy to obtain a lightweight rigid foam, excellent in dimensional stability and mechanical properties of the obtained rigid foam, and excellent in thermal insulation properties of the rigid foam. . However, it is also preferable to use only water as the foaming agent in view of the fact that the use of the fluorine-containing compound gives a load to the environment.

(catalyst)
The catalyst used in the present invention is not particularly limited as long as it is a catalyst that promotes the urethanization reaction. Examples thereof include tertiary amines such as triethylenediamine, bis (2-dimethylaminoethyl) ether, N, N, N ′, N′-tetramethylhexamethylenediamine; and organometallic compounds such as dibutyltin dilaurate. Moreover, you may use together the catalyst which accelerates | stimulates the trimerization reaction of an isocyanate group, and carboxylic acid metal salts, such as potassium acetate and potassium 2-ethylhexanoate, etc. are mentioned. When spray foaming is employed as a method for producing a rigid foam, an organic metal catalyst such as lead 2-ethylhexanoate is preferably used in combination in order to complete the reaction in a short time. As for the usage-amount of a catalyst, 0.1-10 mass parts is preferable with respect to 100 mass parts of polyol compounds.

(Foam stabilizer)
In the present invention, a foam stabilizer is used to form good bubbles. Examples of the foam stabilizer include silicone foam stabilizers and fluorine-containing compound foam stabilizers. Although the usage-amount of a foam stabilizer may be selected suitably, 0.1-10 mass parts is preferable with respect to 100 mass parts of polyol compounds.

(Other ingredients)
In the present invention, any compounding agent can be used in addition to the above-described polyol, polyisocyanate, foaming agent, catalyst, and foam stabilizer. Compounding agents include fillers such as calcium carbonate and barium sulfate; anti-aging agents such as antioxidants and UV absorbers; flame retardants, plasticizers, colorants, anti-fungal agents, foam breakers, dispersants, discoloration prevention Agents and the like.

(Spray method)
The manufacturing method of the rigid foam of this invention is a spray method. Various methods are known for producing foam by the spray method. Among these, airless spray foaming is preferred, in which the compounded liquid is mixed and foamed with a mixing head. Here, spray foaming is a foaming method in which a polyol system solution and a polyisocyanate compound are reacted while sprayed, and the reaction is completed in a short time by selecting a catalyst or the like. Spray foaming is often employed when constructing hard foam insulation on walls, ceilings, etc. at construction sites. Spray foaming has advantages such as manufacturing rigid foams directly at the construction site, thus reducing the construction cost, and being able to construct even on uneven construction surfaces.

  Specific construction examples include heat insulating materials for condominiums, office buildings, prefabricated refrigerated warehouses, and the like. Especially the manufacturing method of the rigid foam of this invention is suitable for construction of the heat insulating material of a freezer warehouse. Since it is excellent in initial adhesiveness and heat insulation performance and hardly causes problems such as lateral flow and cracking, it is suitable for construction of rigid foam by multilayer spraying for the purpose of securing particularly high heat insulation. Specifically, it is suitable for construction when the thickness of the rigid foam layer is 100 mm or more. This is because, in the case of having such a thick foam layer, it is particularly important that the adhesiveness is very high and cracks do not occur. Such a rigid foam layer is difficult to manufacture if only one layer is applied, and multiple layers are required. For example, a foam layer of about 100 mm can be obtained by applying four layers of foam layers of less than 30 mm.

(Rigid foam)
The density of the rigid foam produced by the production method of the present invention is preferably 25 to 40 kg / m ³ . The density can be adjusted by the amount of the foaming agent and can be reduced by using a large amount of foaming agent. However, if a large amount of foaming agent is used, the resulting rigid foam tends to shrink. Moreover, it is preferable that the closed cell rate of the rigid foam manufactured by the manufacturing method of this invention is 85% or more. A high closed cell rate means that the cells formed during foaming of the rigid foam are closed, which leads to high heat insulation performance. On the other hand, if the closed cell ratio is low, the cell has air permeability and the heat insulation performance is low. The closed cell ratio can be adjusted to some extent by selecting the type and amount of the foam stabilizer.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. However, Examples 1-16 are Examples, Examples 17-18 are comparative examples, and each prescription and its evaluation result are shown in the table. Moreover, the unit of the numerical value of the part which showed prescription in the table | surface is a mass part. The raw materials used in Examples and Comparative Examples are as shown in each table, and the details are as follows.

(Polyol)
Polyol A1: A Mannich compound was obtained by reacting 2.2 mol of formaldehyde and 2.2 mol of diethanolamine with 1 mol of nonylphenol. This Mannich compound was subjected to ring-opening addition polymerization of propylene oxide (PO) and ethylene oxide (EO) in this order to obtain a polyether polyol having a viscosity at 25 ° C. of 6000 mPa · s and a hydroxyl value of 430 mgKOH / g. At this time, the ratio of EO to the total amount of PO and EO was 24 mass%.

  Polyol A2: A Mannich compound was obtained by reacting 1.5 mol of formaldehyde and 2.2 mol of diethanolamine with 1 mol of nonylphenol. This Mannich compound was subjected to ring-opening addition polymerization of PO to obtain a polyether polyol having a viscosity at 25 ° C. of 7000 mPa · s and a hydroxyl value of 470 mgKOH / g.

  Polyol A3: 1 mol of nonylphenol was reacted with 1.4 mol of formaldehyde and 2.3 mol of diethanolamine to obtain a Mannich compound. This Mannich compound was subjected to ring-opening addition polymerization of PO and EO in this order to obtain a polyether polyol having a viscosity at 25 ° C. of 1000 mPa · s and a hydroxyl value of 300 mgKOH / g. The ratio of EO to the total amount of PO and EO at this time was 60% by mass.

  Polyol A4: EO, PO and EO were added to toluenediamine in this order by ring-opening addition polymerization to obtain a polyether polyol having a viscosity at 25 ° C. of 7000 mPa · s and a hydroxyl value of 350 mgKOH / g. The ratio of EO to the total amount of PO and EO at this time was 33% by mass.

  Polyol B1: PO and EO were subjected to ring-opening addition polymerization in this order on glycerin to obtain a polyether polyol having a hydroxyl value of 56 mgKOH / g. The ratio of EO to the total amount of PO and EO at this time was 13% by mass.

  Polyol B2: PO and EO were subjected to ring-opening addition polymerization in this order on glycerin to obtain a polyether polyol having a hydroxyl value of 56 mgKOH / g. The ratio of EO to the total amount of PO and EO at this time was 20% by mass.

  Polyol B3: PO and EO were subjected to ring-opening addition polymerization in this order on glycerin to obtain a polyether polyol having a hydroxyl value of 112 mgKOH / g. The ratio of EO to the total amount of PO and EO at this time was 34% by mass.

  Polyol B4: PO and EO were subjected to ring-opening addition polymerization in this order on glycerin to obtain a polyether polyol having a hydroxyl value of 33.5 mgKOH / g. The ratio of EO to the total amount of PO and EO at this time was 16% by mass.

  Polyol C1: Polyethylene polyol having a hydroxyl value of 760 mgKOH / g was obtained by subjecting PO to ethylenediamine to ring-opening addition polymerization.

  Polyol C2: Polyethylene polyol having a hydroxyl value of 550 mgKOH / g was obtained by ring-opening addition polymerization of PO to ethylenediamine.

  Polyol C3: Polyethylene polyol having a hydroxyl value of 350 mgKOH / g was obtained by ring-opening addition polymerization of PO to ethylenediamine.

  Polyol C4: PO was ring-opened and added to monoethanolamine to obtain a polyether polyol having a hydroxyl value of 500 mgKOH / g.

  Polyol C5: Polyether polyol having a hydroxyl value of 350 mgKOH / g was obtained by ring-opening addition polymerization of PO to monoethanolamine.

  Polyol C6: Ring-opening addition polymerization of PO to a mixture of sucrose and diethanolamine (mass ratio: 1.45: 1) gave a polyether polyol having a hydroxyl value of 350 mgKOH / g.

  Polyol C7: Ring-opening addition polymerization of PO to 1- (2-aminoethyl) piperazine was carried out to obtain a polyether polyol having a hydroxyl value of 555 mgKOH / g.

  Polyol D1: PO was ring-opened and added to sorbitol to obtain a polyether polyol having a hydroxyl value of 385 mgKOH / g.

(Example of rigid polyurethane foam production)
The polyols (100 parts by mass in total) shown in Table 1 were mixed and used. Similarly, according to the formulation shown in Table 1, the following catalyst, foam stabilizer and flame retardant were added to and mixed with the polyol mixture and the foaming agent to obtain a polyol composition (polyol system liquid). As a catalyst, a triethylenediamine dipropylene glycol solution (trade name: TEDA-L33, manufactured by Tosoh Corporation) is used as a tertiary amine catalyst, and a mineral spirit solution of lead 2-ethylhexanoate (lead concentration: 20%) as an organometallic catalyst. , Trade name: Nikka Octix Lead 20%, manufactured by Nippon Chemical Industry Co., Ltd.). As the foam stabilizer, a silicone foam stabilizer (trade name: SH-193, manufactured by Toray Dow Corning Silicone) was used. As the flame retardant, tris (2-chloropropyl) phosphate (trade name: Pyrol PCF, manufactured by Akzo Japan) was used. As the polyisocyanate, polymethylene polyphenyl polyisocyanate (trade name: MR-200, manufactured by Nippon Polyurethane Industry Co., Ltd.) was used.

  The prepared polyol system liquid and the polyisocyanate were foamed and reacted with a gasmer spray foaming machine (FF-1600) under the conditions of a liquid temperature of 36 ° C. and a room temperature of 10 ° C., which are the foaming conditions in winter. A polyurethane foam was produced. The discharged material ratio of polyol system liquid / polyisocyanate was 1/1. Foaming by the spray method was performed by spraying using a flexible plate fixed to an iron plate jig having a length of 600 mm, a width of 600 mm, and a thickness of 5 mm as a base material. For the spraying, a lower spray layer of 1 mm in thickness was applied, and then a total of four layers were laminated so that the thickness of one layer was 25 to 30 mm. In the construction, after spraying a certain layer, the time until the next layer starts to be sprayed (hereinafter referred to as the interval) is 0 second (immediately, the next layer is sprayed and laminated), 30 The test was performed in three ways of seconds and 120 seconds.

(Evaluation of rigid polyurethane foam)
Evaluation of the obtained rigid polyurethane foam was performed for each item shown in the table. The core density (unit: kg / m ³ ) was measured according to JIS A9526. The thermal conductivity (unit: mW / m · K) was measured using a thermal conductivity measuring device (Auto Lambda HC-074, manufactured by Eiko Seiki Co., Ltd.) in accordance with JIS A1412. The closed cell ratio (unit:%) was measured using a high-precision automatic volume meter (VM-100 type, manufactured by STEC Co.).

  Moreover, adhesiveness, delamination, and lateral flow were visually observed and evaluated according to the following criteria. However, in the evaluation section in the table, 0 seconds, 30 seconds, and 120 seconds represent interval times, respectively.

Regarding the adhesiveness, one day after the construction, the obtained foam was peeled off from the base material, and the adhesive state at the interface between the base material and the rigid foam layer was observed.
1: Adherent defective portions are observed on almost the entire observation surface, and there are some practical problems.
2: 5 or more small adhesion failure portions are observed in the observation surface, and there are some practical problems.
3: Although 1 to 4 small adhesion failure portions are observed in the observation surface, there is no practical impact.
4: Degree of adhesion is not recognized in the observation surface, and is practically excellent.

In the delamination, one day after the construction, the obtained foam was cut into four parts of 300 mm length and 300 mm width, and then the cut surfaces (observation surfaces) obtained by cutting each of the surrounding 50 mm were used as the interlayer inside the foam. Focusing on (the interface part of a foam layer and a foam layer), it observed visually.
1: Peeling was observed everywhere in the observation surface, and there were some practical problems.
2: Peeling with a length of about 50 to 100 mm was observed in the observation surface, and there were some practical problems.
3: Detachment having a length of 10 mm or more and less than 50 mm in the observation plane is recognized and has no practical effect.
4: Peeling with a length of less than 10 mm is observed in the observation plane, but there is no practical impact.
5: Peeling is not recognized in the observation surface, and is practically excellent.

  The lateral flow was evaluated by measuring the distance (lateral elongation distance, unit: mm) at which the obtained rigid foam extended laterally from the end of the substrate. If this lateral elongation distance is 10 mm or more, there is a problem in practical use and it cannot be used. Moreover, if it is 5 mm or more and less than 10 mm, there is little influence in practical use. Furthermore, if it is less than 5 mm, it can be said that it is excellent practically.

  Examples 1 to 16, which are examples, are excellent values in adhesiveness and delamination because the mixing ratio of the polyol mixture is in a specific range. On the other hand, in Comparative Examples 17 to 18, the ratio of the polyol (B) deviates from the predetermined range (the polyol (B) is not used), so that inappropriate results in adhesion, delamination and lateral flow are obtained. It became. In Example 17, delamination and cracks were severe, and the core density, thermal conductivity, and closed cell ratio could not be measured.

The manufacturing method of the rigid foam which is lightweight and excellent in adhesiveness based on this invention is suitable for construction of the rigid foam by spray foaming constructed | assembled at a construction site.

Claims (6)

In the method of producing a rigid foamed synthetic resin by reacting and foaming a polyol and a polyisocyanate by a spray method in the presence of a foam stabilizer, a catalyst and a foaming agent, the following polyol (A) is used as the polyol: A method for producing a rigid foam synthetic resin, comprising using a polyol mixture containing -60% by mass and 5-30% by mass of the following polyol (B) based on the total polyol mixture.
Polyol (A): A polyether polyol having a hydroxyl value of 200 to 500 mgKOH / g, obtained by ring-opening addition polymerization of an alkylene oxide to an aromatic nitrogen-containing compound.
Polyol (B): A polyether polyol having a hydroxyl number of 2 to 4 and a hydroxyl value of 25 to 200 mgKOH / g, obtained by ring-opening addition polymerization of an alkylene oxide to a polyhydric alcohol.   The method for producing a rigid foam synthetic resin according to claim 1, wherein the aromatic nitrogen-containing compound in the polyol (A) is a Mannich compound obtained by reacting phenols, aldehydes, and alkanolamines.   The method for producing a rigid foam synthetic resin according to claim 1 or 2, wherein propylene oxide is used as the alkylene oxide in the polyol (B), and the proportion of propylene oxide is 50 to 95 mass% with respect to the total amount of alkylene oxide. The method for producing a rigid foam synthetic resin according to claim 1, 2, or 3, wherein a polyol mixture further containing 10 to 85% by mass of the following polyol (C) as the polyol is used.
Polyol (C): A polyether polyol having a hydroxyl value of 250 to 800 mgKOH / g, obtained by ring-opening addition polymerization of an alkylene oxide to an aliphatic nitrogen-containing compound or alicyclic nitrogen-containing compound.   The said spraying method is multilayer spraying, The manufacturing method of the hard foam synthetic resin in any one of Claims 1-4. The method for producing a rigid foam synthetic resin according to claim 1, wherein the produced rigid foam synthetic resin has a closed cell ratio of 85% or more.