Polyurethane foam and insulation materials

Abstract

The present invention provides a polyurethane foam that can maintain its thermal insulation properties for a long period of time, and a thermal insulation material using the same. [Solution] The polyurethane foam is obtained from a raw material composition containing hydroxylated cyclic carbonate and hydrocarbons. Thus, the raw material composition contains hydrocarbons as physical blowing agents and hydroxylated cyclic carbonate. As a result, the reaction between the polyisocyanate component and the hydroxylated cyclic carbonate rapidly promotes resinification simultaneously with the generation of CO2. Consequently, the inside of the cell becomes pressurized due to foaming by hydrocarbons and foaming by the reaction between the polyisocyanate component and the hydroxylated cyclic carbonate, requiring time for replacement with air, which has low thermal insulation properties. As a result, the polyurethane foam can maintain its thermal insulation properties over a long period of time.

Description

[Technical Field]

[0001] The present invention relates to polyurethane foam and thermal insulation materials, and more particularly to polyurethane foam with improved thermal insulation properties and thermal insulation materials using the same. [Background technology]

[0002] In recent years, energy conservation has been strongly advocated in homes and other buildings from the perspective of reducing energy consumption. In houses and other buildings, the use of indoor air conditioning and other heating systems accounts for a relatively large portion of energy consumption. Therefore, the role of insulation materials in reducing disturbances from the outdoor environment becomes extremely important.

[0003] Rigid polyurethane foam is widely used as insulation in houses and other buildings. Therefore, improving the insulation properties of rigid polyurethane foam is crucial for energy conservation in these structures.

[0004] Various proposals have been made for rigid polyurethane foam with high thermal insulation properties. For example, Patent Document 1 contains: It is obtained by mixing and reacting polyol, polyisocyanate, a blowing agent, and a trimerizing catalyst as essential components. The nurating rate is 30-40%. The percentage of closed cells is 75% or higher. Polyisocyanurate foam is listed.

[0005] The document states that the above configuration makes it possible to provide a polyisocyanurate foam that has a good balance of flame retardancy and high thermal insulation properties. Furthermore, the same document states that the thermal insulation performance can be improved by using hydrofluoroolefins as a physical blowing agent. This is likely because the thermal insulation performance of rigid polyurethane foam largely depends on the thermal conductivity of the gas sealed within the cells, and using hydrofluoroolefins, which have low thermal conductivity, as a physical blowing agent is the result of this improvement.

[0006] Generally, chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), and hydrofluoroolefins (HFOs) have low thermal conductivity and have therefore been actively used as physical blowing agents in rigid polyurethane foams where thermal insulation is required.

[0007] However, CFCs have a high ozone depletion potential (ODP), so their use is currently restricted. Furthermore, although HFCs have a low ODP (Optical Discharge Potential), their use is restricted due to their high Global Warming Potential (GWP). Furthermore, although HFOs have low ODP and GWP, there are concerns about their continued use in the future from the perspective of per- and polyfluorine-alkyl substances (PFAS).

[0008] In Patent Document 2, (1) Glycerol carbonate, and (2) Physical blowing agents and / or chemical blowing agents Polyurethane foaming agent composition containing This has been proposed.

[0009] The document states that polyurethane foam produced using the above polyurethane foaming agent composition has low thermal conductivity (= high thermal insulation properties) while maintaining low ODP and GWP.

[0010] As a specific example, the same document describes that by using methyl formate as a physical blowing agent and glycerol carbonate as a chemical blowing agent, a polyurethane foam having high heat insulation properties can be formed. Methyl formate has low ODP and GWP, and also has a relatively low thermal conductivity. However, methyl formate is not only a concern for corrosion of equipment and piping, but also lacks storage stability of raw materials, so its use is hesitant.

[0011] Therefore, as a specific example without using a physical blowing agent, the same document describes that a polyurethane foam having high heat insulation properties can be formed by using only a chemical blowing agent containing glycerol carbonate and water.

[0012] Here, glycerol carbonate and water, which are chemical blowing agents, generate CO2 by reacting with isocyanate. Therefore, when no physical blowing agent is used and only a chemical blowing agent containing glycerol carbonate and water is used, it is considered that the cells are mainly filled with CO2.

[0013] However, since CO2 has a small molecular weight, it easily escapes outside the cells through the cell walls. Therefore, the atmosphere inside the cells is easily replaced by air. Here, since the thermal conductivity of air is higher than that of CO2 (i.e., the heat insulation property is lower), in the configuration of Patent Document 2, there is a risk that the heat insulation property will greatly decrease in a short period after production.

Prior Art Documents

Patent Documents

[0014]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0015] The problem to be solved by the present invention is to provide a polyurethane foam capable of maintaining heat insulation properties for a long period of time. Another problem to be solved by the present invention is to provide a heat insulating material using such a polyurethane foam.

Means for Solving the Problems

[0016] In order to solve the above problems, The polyurethane foam according to the present invention is obtained from a raw material composition containing a hydroxyl group-containing cyclic carbonate and a hydrocarbon.

[0017] In order to solve the above problems, The heat insulating material according to the present invention includes the polyurethane foam according to the present invention.

Effects of the Invention

[0018] The raw material composition contains a hydrocarbon as a physical foaming agent and a hydroxyl group-containing cyclic carbonate. Here, since the reactivity of the hydroxyl group-containing cyclic carbonate is very high, when the polyisocyanate component and the hydroxyl group-containing cyclic carbonate react, resinification of the cell walls rapidly proceeds simultaneously with the generation of CO2. As a result, each cell is foamed by the hydrocarbon and the reaction between the polyisocyanate component and the hydroxyl group-containing cyclic carbonate, and becomes a pressurized state and is sealed.

[0019] Here, from the cells in the pressurized state, first, CO2 with a small molecular weight gradually escapes, and the inside of the cells becomes a state filled only with the hydrocarbon and is in equilibrium with the atmospheric pressure. Next, the hydrocarbon in the cells is gradually replaced with air. Therefore, it takes time until the hydrocarbon in the cells is replaced with air having low heat insulation properties. In other words, the hydrocarbon having relatively high heat insulation properties remains in the cells for a longer period of time. From this, the rigid polyurethane foam can maintain heat insulation properties for a long period of time.

[0020] One embodiment of the present invention will be described in detail below. [1. Polyurethane foam] The polyurethane foam according to the present invention is It is obtained by reacting and foaming a raw material composition (raw material mixture) containing a hydrated cyclic carbonate and a hydrocarbon.

[0021] [1.1. Raw material composition] The raw material composition is a mixture of liquid A containing a polyol component, liquid B containing a polyisocyanate component, and a hydrocarbon which is a physical blowing agent. [1.1.1. A liquid] Solution A contains a polyol component and a hydrated cyclic carbonate. Solution A may further contain a catalyst, a foam stabilizer, a flame retardant, etc.

[0022] [1.1.1.1. Polyol components] The polyol component may contain only one type of polyol, or it may contain two or more types of polyols. Polyols for polyurethane foam can be used as the polyol component. Examples of polyols include polyether polyols, polyester polyols, and polyether ester polyols.

[0023] Examples of polyether polyols include polyether polyols obtained by adding alkylene oxides such as ethylene oxide and propylene oxide to polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, and sucrose.

[0024] Examples of polyester polyols include those obtained by polycondensation of aliphatic carboxylic acids such as malonic acid, succinic acid, and adipic acid, or aromatic carboxylic acids such as phthalic acid, with aliphatic glycols such as ethylene glycol, diethylene glycol, and propylene glycol.

[0025] Examples of polyether ester polyols include those obtained by reacting the aforementioned polyether polyol with a polybasic acid to produce polyester, or those having polyether and polyester segments within a single molecule.

[0026] Here, the polyol component may include both high molecular weight polyols and low molecular weight polyols.

[0027] [1.1.1.1.1. High molecular weight polyols] High molecular weight polyols primarily affect the physical properties of the foam, such as its strength and elongation. Furthermore, from the viewpoint of the strength of the formed foam, it is preferable to use polyester polyol as the high molecular weight polyol.

[0028] [a. Average hydroxyl value] The average hydroxyl value of high molecular weight polyols primarily affects the hardness of the foam. If the average hydroxyl value of high molecular weight polyols becomes too high, the foam may become excessively hard and brittle. For this reason, the average hydroxyl value of high molecular weight polyols is preferably 400 or less. It is preferably 350 or less, and more preferably 300 or less.

[0029] On the other hand, if the average hydroxyl value of a high molecular weight polyol becomes too low, its reactivity may decrease. For this reason, the average hydroxyl value of a high molecular weight polyol is preferably 20 or higher. It is preferably 50 or higher, and more preferably 100 or higher.

[0030] [b. Average number of functional groups] The average number of functional groups in a high molecular weight polyol primarily affects the strength of the foam. If the average number of functional groups in a high molecular weight polyol is too low, the resin strength may not be maintained. Therefore, to maintain the required resin strength, it is preferable that the average number of functional groups in a high molecular weight polyol be 2.0 or higher. Preferably, it is 2.5 or higher, and more preferably 2.7 or higher.

[0031] On the other hand, if the average number of functional groups in a high molecular weight polyol becomes too high, the foam may become excessively hard and brittle. It may also inhibit the reaction of the catalyst. For this reason, the average number of functional groups in a high molecular weight polyol needs to be 8.0 or less. Preferably, the average number of functional groups is 7.0 or less, and more preferably 6.0 or less.

[0032] In this case, if the foam is a so-called polyisocyanurate foam, it is even more preferable to set the average number of functional groups of the high molecular weight polyol to 2.0 or more and 3.0 or less so as not to inhibit the nurating process by the trimerization catalyst. Furthermore, if the foam is a so-called rigid polyurethane foam, it is necessary to ensure rigidity with polyols, so it is even more preferable to set the average number of functional groups of the high molecular weight polyol to 3.0 or more and 8.0 or less.

[0033] Furthermore, the high molecular weight polyol is preferably a polyester polyol obtained by dehydrating and condensing orthophthalic acid or terephthalic acid with diethylene glycol. This is because the more aromatic rings there are, the more flame retardant the foam can be made, and by using such polyester polyols, flame retardancy can be imparted to the foam.

[0034] [1.1.1.1.2. Low molecular weight polyols] Low molecular weight polyols act as crosslinking agents. Furthermore, by preferentially reacting with polyisocyanate components in the initial stages of the reaction, the heat generated by this reaction can further accelerate other reactions in the raw material composition.

[0035] [a. Average hydroxyl value] The average hydroxyl value of low molecular weight polyols affects the hardness of the foam. If the average hydroxyl value of low molecular weight polyols becomes too high, the foam may become excessively hard and brittle. For this reason, the average hydroxyl value of low molecular weight polyols is preferably 1700 or less. It is preferably 1600 or less, and more preferably 1400 or less.

[0036] On the other hand, if the average hydroxyl value of a low molecular weight polyol becomes too low, its reactivity may decrease. Furthermore, a decrease in reactivity can lead to a decrease in the exothermic temperature, which may inhibit the activity of the catalyst. For this reason, it is preferable that the average hydroxyl value of a low molecular weight polyol be greater than 400. It is preferable that the average hydroxyl value be 450 or higher, and more preferably 500 or higher.

[0037] [b. Average number of functional groups] The average number of functional groups in a low molecular weight polyol primarily affects the foam's strength. If the average number of functional groups in a low molecular weight polyol is too low, there may be too few crosslinking points, making it difficult to maintain sufficient resin strength. Therefore, to maintain the required resin strength, it is preferable that the average number of functional groups in a low molecular weight polyol be 2.0 or higher. Preferably, it is 2.5 or higher, and more preferably 2.7 or higher.

[0038] On the other hand, if the average number of functional groups in a low molecular weight polyol becomes too high, the number of crosslinking points may increase excessively, making the foam excessively hard and brittle. For this reason, the average number of functional groups in a low molecular weight polyol is preferably 6.0 or less. It is preferably 5.0 or less, and more preferably 4.0 or less.

[0039] In this case, if the foam is a so-called rigid polyurethane foam, it is possible to form the foam using only low molecular weight polyols by adjusting the average hydroxyl value and the average number of functional groups. Furthermore, in the case of a so-called polyisocyanurate foam, it is preferable that a low molecular weight polyol is included as a polyol component to serve as a heat source for nurating by a trimerizing catalyst.

[0040] Furthermore, the low molecular weight polyols are not particularly limited, and the most suitable one can be selected depending on the purpose. By selecting a polyether polyol as the low molecular weight polyol, water resistance can be imparted to the foam. This suppresses the hydrolysis of the foam, prevents air from entering the cells, and further improves insulation.

[0041] [1.1.1.2. Hydrated cyclic carbonates] Solution A contains a hydrated cyclic carbonate. Here, a hydroxylated cyclic carbonate is a cyclic carbonate that has at least one OH group.

[0042] Hydrated cyclic carbonates are not particularly limited and can have structures such as those shown in Chemical Formula 1. [ka]

[0043] Here, R1 is -CH2-, -CH(OH)-CH2-, -C4H3O3-, ―CH(―CH(OH)―CH2―O―CO―O―CH3)―, ―C3H2O3―, ―CH(O―CO―O―CH3)―CH(OH)―CH2―, Examples include —CH(OH)—C3H3O3—, —[CH(OH)]3—CH2—, —C4H5O(OH)—, etc. [ka]

[0044] Furthermore, the hydrated cyclic carbonate shown in chemical formula 1 reacts with two isocyanate groups to form the structure shown in chemical formula 3 and release CO2. More specifically, first, the OH group of the hydroxylated cyclic carbonate reacts with the isocyanate group to form a urethane bond. Next, at temperatures above 100°C, the CO2 from the cyclic carbonate group is removed, forming an epoxy group. Next, the formed epoxy groups react with isocyanate groups, crosslinking while forming an oxazolidinone skeleton.

[0045] [ka] Here, R2 and R3 are groups that are linked to the isocyanate group, respectively. Furthermore, as the hydroxylated cyclic carbonate, it is preferable to use glycerol carbonate in which R1 in chemical formula 1 is -CH2- due to its easy availability.

[0046] [1.1.1.3. Catalyst] Solution A may contain a catalyst. A "catalyst" refers to catalysts that primarily promote resin formation reactions, which are mainly reactions between hydroxyl groups and isocyanate groups; foaming catalysts that primarily promote foaming reactions, which are mainly reactions between water and isocyanate groups; catalysts that promote both resin formation and foaming reactions; catalysts that increase the amount of isocyanate groups, etc.

[0047] Examples of catalysts include amine-based catalysts and metal-based catalysts as resin-forming catalysts, amine-based catalysts as foaming catalysts, and quaternary ammonium salts and metal salts as trimerization catalysts. Amine-based catalysts are examples of catalysts that promote either or both of the resinification reaction and the foaming reaction. Metal-based catalysts are primarily used as catalysts that accelerate resin formation reactions. A trimerization catalyst is a catalyst that trimers isocyanates to produce isocyanurate groups.

[0048] Examples of amine-based catalysts include, N,N-dimethylcyclohexylamine, N,N-dimethylbenzylamine, N,N-dimethylaminoethanol, N,N-dimethylaminohexanol, N,N',N'-trimethylaminoethylpiperazine, triethylenediamine These are some examples.

[0049] Examples of metal catalysts include, Tin catalysts such as stanus octoate and dibutyltin dilaurate, Mercury catalysts such as phenylmercurypropionate, Lead catalysts such as lead octonate These are some examples.

[0050] Examples of trimerization catalysts include, Metal salt catalysts such as potassium carboxylate, potassium acetate, and potassium octylate, Amine-based catalysts such as 2,4,6-tris(dimethylaminomethyl)phenol and triethylenediamine, Quaternary ammonium salt catalysts such as triethylmethylammonium diethylhexane salt. These are some examples.

[0051] Furthermore, in the case of polyurethane foam, there is a correlation between cell size and thermal insulation performance; the smaller the cell size, the better the thermal insulation performance. Therefore, in order to impart thermal insulation properties to the foam, it is preferable to add a resin catalyst to adjust the cell size. Furthermore, in urethane foam, the formation of isocyanurate groups improves flame retardancy. Therefore, in order to impart flame retardancy to the foam, it is preferable to add a trimerizing catalyst for the formation of isocyanurate groups.

[0052] [1.1.1.4. Foam stabilizers] Solution A may contain a foam stabilizer. A "foam stabilizer" is an additive that improves the mixing properties of raw materials with different polarities, or that makes the size and distribution of bubbles more uniform. When a foam stabilizer is added to the raw material composition, a polyurethane foam with uniform bubble size and distribution can be obtained. Examples of foam stabilizers include silicone-based foam stabilizers, fluorine-containing compound-based foam stabilizers, and known surfactants.

[0053] [1.1.2. B liquid] Solution B contains a polyisocyanate component. [1.1.2.1. Polyisocyanate components] The polyisocyanate component may contain only one type of polyisocyanate, or it may contain two or more types of polyisocyanates. Furthermore, the number of functional groups in polyisocyanates is not particularly limited, and the optimal number of functional groups can be selected according to the purpose.

[0054] Examples of polyisocyanates include aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, and modified polyisocyanates obtained by modifying these.

[0055] Examples of aromatic polyisocyanates include, Diphenylmethane diisocyanate (MDI), Tolylene diisocyanate (TDI), Naphthalene diisocyanate (NDI), p-phenylenediisocyanate (PPDI), xylenediisocyanate (XDI), Tetramethylxylene diisocyanate (TMXDI), Examples include toridine diisocyanate (TODI).

[0056] Examples of aliphatic polyisocyanates include, Hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), Examples include lysine triisocyanate (LTI).

[0057] Examples of alicyclic polyisocyanates include, Isophorone diisocyanate (IPDI), Cyclohexyl diisocyanate (CHDI), hydrogenated XDI (H6XDI), Hydrogenated MDI(H 12 Examples include MDI (Multi-Distributed Injection).

[0058] Examples of modified polyisocyanates include urethane-modified polyisocyanates, allophanate-modified polyisocyanates, biuret-modified polyisocyanates, urea-modified polyisocyanates, and isocyanate-terminated prepolymers.

[0059] [1.1.3. Hydrocarbons] The raw material composition contains hydrocarbons as a physical foaming agent. A "physical foaming agent" is an additive that generates bubbles in a liquid raw material composition during the resinification process by generating gas through a pressure drop or heating. Furthermore, hydrocarbons have low ODP and GWP, and relatively low thermal conductivity, making them suitable for use as thermal insulation materials.

[0060] [1.1.4. Flame retardants] Solution A may contain a flame retardant. Flame retardants are additives that impart flame retardancy to foam.

[0061] Examples of flame retardants include, Phosphorus compounds such as ammonium polyphosphate and melamine phosphate, Metal hydrates such as aluminum hydroxide, calcium hydroxide, and magnesium hydroxide. Phosphate ester compounds such as tris-2-chloroethyl phosphate (TCEP), tris-1,3-dichloro-2-propyl phosphate (TDCP), tris-1-chloro-2-propyl phosphate (TCPP), and triethyl phosphate (TEP). These are some examples.

[0062] As a flame retardant, phosphate ester compounds are preferred, and halogenated phosphate esters are particularly preferred. This is because halogens act as radical traps during combustion, and phosphorus contributes to the formation of a dehydrated carbonized layer.

[0063] [1.1.5. Water] In the raw material composition, the less water there is, the better. Water functions not only as a "chemical blowing agent" that generates gas through chemical reactions, but also as a "blowing aid" that regulates the temperature during the foaming of the "blowing agent." Furthermore, "water" includes not only water that has been intentionally added, but also water that has been inevitably mixed in.

[0064] [1.1.6. Other Additives] The raw material composition may, if necessary, contain antioxidants, pigments, scorch inhibitors, etc.

[0065] [1.2. Content] [1.2.1. Content of low molecular weight polyols] "Low molecular weight polyol content" refers to the mass of low molecular weight polyols when the mass of high molecular weight polyols is set to 100 in the presence of high molecular weight polyols, and is expressed in units of "parts by mass."

[0066] If the low molecular weight polyol content is too low, the initial reaction with the polyisocyanate component decreases, resulting in insufficient reaction heat and potentially lowering the overall reaction activity. Therefore, the low molecular weight polyol content is preferably 1 part by mass or more. Preferably, the content is 5 parts by mass or more, and more preferably 8 parts by mass or more.

[0067] On the other hand, if the content of low molecular weight polyols becomes too high, the heat resistance may deteriorate due to the relative decrease in high molecular weight polyols. Also, the strength may decrease due to the relative decrease in high molecular weight polyols. Furthermore, the crosslinking density may become excessively high, making the foam hard and brittle. Therefore, the content of low molecular weight polyols is preferably 100 parts by mass or less. The content is preferably 70 parts by mass or less, and more preferably 50 parts by mass or less.

[0068] [1.2.3. Content of hydroxylated cyclic carbonates] "Hydroxycyclic carbonate content" refers to the ratio of the mass of hydroxycyclic carbonate to the total mass of the raw material composition.

[0069] If the content of hydroxylated cyclic carbonate is too low, the thermal insulation properties of the foam may not be maintained over the long term. Therefore, the content of hydroxylated cyclic carbonate is preferably 0.01% by mass or more. The content is preferably 0.1% by mass or more, and more preferably 0.3% by mass or more.

[0070] On the other hand, if the content of hydroxylated cyclic carbonate becomes too high, voids may form on the surface of the foam. Also, the exothermic temperature due to the reaction may become excessively high, causing scorching (burning, charring) of the foam. Therefore, the content of hydroxylated cyclic carbonate is preferably 5.0% by mass or less. The content is preferably 4.5% by mass or less, and more preferably 4.0% by mass or less.

[0071] [1.2.2. Total Catalyst Content] "Total catalyst content" refers to the ratio of the total mass of catalyst to the total mass of the raw material composition.

[0072] Generally, the higher the total catalyst content, the faster the reaction proceeds. To obtain this effect, the total catalyst content is preferably 0.3% by mass or more. A total content of 1.0% by mass or more is preferable, and 1.5% by mass or more is more preferable.

[0073] On the other hand, if the total catalyst content is excessive, the foam may become excessively hard and brittle. Therefore, the total catalyst content is preferably 5.0% by mass or less. The total content is preferably 4.5% by mass or less, and more preferably 4.0% by mass or less.

[0074] [1.2.2.1. Content of Trimerization Catalyst] "Trimerization catalyst content" refers to the ratio of the mass of the trimerization catalyst to the total mass of the raw material composition.

[0075] If the trimerizing catalyst content is too low, the isocyanurate groups formed may be insufficient, and the intended flame retardancy may not be achieved. Therefore, the trimerizing catalyst content is preferably 0.15% by mass or more. The content is preferably 0.3% by mass or more, and more preferably 1.0% by mass or more.

[0076] If the trimerizing catalyst content is too high, the reaction rate becomes excessively fast, which may prevent the formation of the foam. Therefore, the trimerizing catalyst content is preferably 5.0% by mass or less. The content is preferably 3.0% by mass or less, and more preferably 2.0% by mass or less.

[0077] [1.2.3. Foam stabilizer content] "Foam stabilizer content" refers to the ratio of the mass of the foam stabilizer to the total mass of the raw material composition.

[0078] If the foam stabilizer content is too low, the cell size may become too large, which can worsen the heat insulation performance. Therefore, the foam stabilizer content is preferably 0.5% by mass or more. A content of 1.0% by mass or more is preferable, and 1.5% by mass or more is more preferable.

[0079] On the other hand, increasing the foam stabilizer content too much does not make any difference in effect and is not beneficial. Therefore, the foam stabilizer content is preferably 5.0% by mass or less. The content is preferably 4.5% by mass or less, and more preferably 4.0% by mass or less.

[0080] [1.2.4. Hydrocarbon (physical blowing agent) content] "Hydroxide (physical blowing agent) content" refers to the ratio of the mass of hydrocarbons to the total mass of the raw material composition.

[0081] If the hydrocarbon content is too low, foaming may not occur. Also, the density of the foam may become excessively high. Therefore, the hydrocarbon content is preferably 1.0% by mass or more. Preferably, it is 2.0% by mass or more, and more preferably 3.0% by mass or more.

[0082] On the other hand, if the hydrocarbon content is too high, excessive foaming may prevent the formation of the intended uniform cells. Therefore, the hydrocarbon content is preferably 10.0% by mass or less. Preferably, it is 9.0% by mass or less, and more preferably 8.0% by mass or less.

[0083] Furthermore, it is preferable that the hydrocarbon content in the raw material composition is greater than the hydroxylated cyclic carbonate content. This allows for an increase in the proportion of hydrocarbons with low thermal conductivity within the cell, thereby improving the thermal insulation properties of the foam.

[0084] [1.2.5. Polyisocyanate content] The "isocyanate index" is the value obtained by multiplying the ratio of the equivalent amount of isocyanate groups in the polyisocyanate component of the raw material composition to the equivalent amount of active hydrogen groups in the raw material composition by 100.

[0085] If the isocyanate index becomes too low, the crosslinking density may decrease excessively, potentially leading to a reduction in strength. Therefore, an isocyanate index of 120 or higher is preferable. Preferably, the isocyanate index is 200 or higher, and more preferably 300 or higher.

[0086] On the other hand, if the isocyanate index becomes too high, the crosslinking density may become too high, causing the foam to become excessively hard and brittle. Therefore, an isocyanate index of 1000 or less is preferable. Preferably, the isocyanate index is 800 or less, and more preferably 600 or less.

[0087] In this case, if the foam is a so-called polyisocyanurate foam, it is even more preferable to set the isocyanate index to 300 or more and 600 or less, taking into consideration the promotion of nuration by the trimerization catalyst. Furthermore, if the foam is a so-called rigid polyurethane foam, it is even more preferable to set the isocyanate index to 120 or more and 150 or less, taking into consideration the need to ensure sufficient reaction with hydroxyl cyclic carbonate.

[0088] [1.2.6. Flame retardant content] "Flame retardant content" refers to the ratio of the mass of the flame retardant to the total mass of the raw material composition.

[0089] If the flame retardant content is too low, the intended flame retardancy may not be achieved. Therefore, the flame retardant content is preferably 0.1% by mass or more. A content of 1.0% by mass or more is preferable, and 3.0% by mass or more is more preferable.

[0090] On the other hand, if the flame retardant content is too high, unreacted flame retardant may remain as a liquid, which can reduce the strength of the foam. Therefore, the content is preferably 25.0% by mass or less, and more preferably 20.0% by mass or less.

[0091] [1.2.7. Water content] "Water content" refers to the ratio of the mass of water to the total mass of the raw material composition.

[0092] If the water content becomes too high, the exothermic temperature from the reaction may become excessively high, potentially causing scorching (burning or charring) of the foam. Furthermore, the reaction with the polyisocyanate component may form urea, making the foam hard and brittle. Additionally, the formation of urea balls may impair the crystallinity of the resin, increasing gas permeability and potentially worsening its thermal insulation properties. Therefore, the water content is preferably 0.5% by mass or less, more preferably 0.1% by mass or less, and more preferably 0.05% by mass or less. Furthermore, the "water content" includes not only water that was intentionally added, but also water that was inevitably mixed in.

[0093] [1.2.8. Content of other additives] "Content of other additives" refers to the ratio of the mass of other additives to the total mass of the raw material composition. The amount of other additives should be adjusted as needed to ensure that each additive performs its function.

[0094] [1.3. Method for manufacturing polyurethane foam] Polyurethane foam is It is obtained by reacting and foaming a raw material composition which is a mixture of liquid A containing polyol components and hydrated cyclic carbonates, liquid B containing polyisocyanate components, and hydrocarbons.

[0095] The polyurethane foam according to the present invention may be manufactured using any of the following methods: slab foaming, mold foaming, continuous molding, spraying, etc. "Slab foaming" refers to a manufacturing method in which a raw material composition is discharged onto a belt conveyor and the foaming process is carried out under atmospheric pressure and at room temperature. "Mold foaming" refers to a manufacturing method in which a raw material composition is injected into the cavity of a mold, and the foaming process is carried out within the cavity. The "continuous molding method" refers to a manufacturing method in which a flat sheet can be formed by using a high-pressure injection machine to foam and harden a mixed raw material composition in a double conveyor at room temperature and atmospheric pressure. The basic manufacturing method for laminates can be applied to conventionally known methods, such as those described in Japanese Patent Publication No. 2007-176990 and Japanese Patent Publication No. 2006-168360. The "spray method" refers to a manufacturing method in which a mixed raw material composition is sprayed onto an object at room temperature and atmospheric pressure using a high-pressure injection machine, and then foamed and hardened to obtain urethane foam that adheres to the object.

[0096] [1.4. Insulation] The thermal insulation material according to the present invention comprises the polyurethane foam according to the present invention. The insulation material may also be a laminate board with facing material on both the front and back surfaces.

[0097] [1.5. Characteristics] [1.5.1. Closed-cell ratio] "Closed cell ratio" refers to the value measured in accordance with ASTM D2856.

[0098] If the closed-cell ratio is too low, the intended thermal insulation may not be achieved. Therefore, a closed-cell ratio of 75% or higher is preferable. A closed-cell ratio of 80% or higher is preferable, and 90% or higher is more preferable.

[0099] [1.5.2. Core Density] "Core density" refers to the density of the core portion (the area excluding a 5mm radius from the front and back surfaces), and "density" refers to the value measured in accordance with JIS A9521.

[0100] The core density of polyurethane foam primarily depends on the amount of foaming agent. If the core density becomes too low, the cell size can become excessively large, potentially worsening the insulation performance. Therefore, the core density should be 25 kg / m³. 3 The above is preferable. The core density is 27 kg / m³. 3 The above is preferable, 30 kg / m 3 It is more preferable that the above conditions are met.

[0101] On the other hand, if the core density becomes too high, the cell wall becomes thick, and thus heat conduction through the cell wall cannot be ignored, which may deteriorate the heat insulation performance. Therefore, the core density is preferably 60 kg / m 3 or less. The core density is preferably 50 kg / m 3 or less, and more preferably 45 kg / m 3 or less.

[0102] [1.5.3. Nurate conversion rate] The "nurate conversion rate" refers to the value represented by the following formula (i). Nurate conversion rate = [a / (a + b + c + d)] …(i) a is the absorption peak position based on the nurate ring in the infrared absorption spectrum: 1400 cm -1 , the area position: 1347.03 cm -1 ~1464.67 cm -1 of the area, b is the absorption peak position based on [N-H] of urethane-urea in the infrared absorption spectrum: 1510 cm -1 , the area position: 1460.81 cm -1 ~1562.06 cm -1 of the area c is the absorption peak position based on [C=O] of urea in the infrared absorption spectrum: 1595 cm -1 , the area position: 1566.88 cm -1 ~1638.23 cm -1 of the area, d is the absorption peak position based on [C=O] of urethane-nurate in the infrared absorption spectrum: 1710 cm -1 , the area position: 1636.3 cm -1 ~1768.4 cm -1 of the area.

[0103] In the case of isocyanurate foam, if the nurate conversion rate becomes too low, the intended flame retardancy may not be imparted to the foam. Therefore, the nurate conversion rate is preferably 30% or more. The nurate conversion rate is preferably 32% or more, and more preferably 34% or more.

[0104] On the other hand, if the nurating rate becomes too high, the foam may become excessively hard and brittle. Therefore, a nurating rate of 40% or less is preferable. A nurating rate of 38% or less is preferable, and 36% or less is more preferable.

[0105] [1.5.4. Change rate of thermal conductivity] "The rate of change of thermal conductivity" refers to the value expressed by the following equation (ii). Change rate of thermal conductivity (%) = (λ35 - λ1) / λ1 × 100 …(ii) however, The rigid polyurethane foam measures 200mm x 200mm x 50mm, with facing materials made of polyethylene / kraft paper / polyethylene on both sides, and is stored in a 60°C constant temperature chamber. λ1 is the thermal conductivity measured one day after the date of manufacture. λ35 is the thermal conductivity measured 35 days after the date of manufacture. That is the case.

[0106] If the rate of change in thermal conductivity is too large, the thermal insulation performance may deteriorate in a short period of time. Therefore, it is preferable that the rate of change in thermal conductivity be 4.0% or less. It is preferable that the rate of change in thermal conductivity be 3.8% or less, and more preferably 3.5% or less.

[0107] [1.6. Effect] The raw material composition contains a hydrocarbon as a physical blowing agent and a hydrated cyclic carbonate. Therefore, the reaction between the polyisocyanate component and the hydrated cyclic carbonate rapidly promotes the resinification of the cell wall, simultaneously generating CO2. As a result, the inside of the cell becomes pressurized due to foaming caused by hydrocarbons and foaming caused by the reaction between the polyisocyanate component and the hydrated cyclic carbonate.

[0108] In this state, as the cell is pressurized, the CO2, which has a small molecular weight, gradually escapes first, and the cell becomes equilibrium with atmospheric pressure with only hydrocarbons remaining inside. Next, the hydrocarbons in the cell are gradually replaced by air. Therefore, it takes time for the hydrocarbons inside the cell to be replaced by air, which has poorer thermal insulation properties. In other words, the hydrocarbons remain inside the cell for a longer period of time. Therefore, rigid polyurethane foam can maintain its thermal insulation properties for a long period of time.

[0109] Furthermore, since the physical blowing agent is a hydrocarbon, and hydrocarbons have relatively low thermal conductivity, the thermal insulation can be further improved. Furthermore, if the physical blowing agent is a cyclic hydrocarbon, its low polarity results in low affinity for the cell wall containing the highly polar structure of chemical formula 3. Therefore, the cyclic hydrocarbon is less likely to approach the cell wall, requiring more time for air exchange. In other words, using cyclic hydrocarbons as physical blowing agents means that the cyclic hydrocarbons will remain in the cell for a longer period of time. Furthermore, due to their availability, hydrocarbons with 4 to 6 carbon atoms are preferred. [Examples]

[0110] [1. Sample Preparation] [Examples 1-3, Comparative Example 1] [1.1. Raw materials] [1.1.1. A liquid] The following ingredients were used as raw materials for Solution A. Note that Examples 1-3 and Comparative Example 1 differ in the presence or absence of hydrated cyclic carbonate. Examples 1-3 and Comparative Example 1 are so-called polyisocyanurate foams. (1) High molecular weight polyol: Polyester polyol obtained by dehydration condensation of orthophthalic acid and diethylene glycol (DEG) (OHV: 400 mg KOH / g, weight-average molecular weight: 510) (2) Low molecular weight polyol: Diethylene glycol (DEG) (OHV: 1057 mg KOH / g) (3) Hydroxylated cyclic carbonates: Glycerol carbonates (4) Trimerization catalyst 1: Potassium octoate (5) Trimerization catalyst 2:2,4,6-tris(dimethylaminomethyl)phenol (manufactured by Nacalai Tex, "Rubeac DMP-30") (6) Foam stabilizer: Silicone foam stabilizer (Momentive, "Niax Silicone L-6635") (7) Flame retardant: Tris-1-chloro-2-propyl phosphate (TMCPP) (manufactured by Daihachi Chemical Industry Co., Ltd.)

[0111] [1.1.2. B liquid] The following ingredients are used for solution B. (8) Polyisocyanate: Crude MDI (manufactured by Tosoh Corporation, "MR-200")

[0112] [1.1.3. Hydrocarbons] The following materials were used as raw materials for the hydrocarbons. (9) Hydrocarbons: Cyclopentane (Marukazol FH, manufactured by Maruzen Petroleum Co., Ltd.)

[0113] [Example 4, Comparative Example 2] [1.2. Raw materials] [1.2.1. A liquid] The following ingredients were used as raw materials for Solution A. Note that Example 4 and Comparative Example 2 differ in the presence or absence of hydrated cyclic carbonate. Note that Example 4 and Comparative Example 2 are so-called rigid polyurethane foams. (1) Low molecular weight polyol 1: polyether polyol (OHV: 550 mg KOH / g, f=6) (manufactured by AGC Inc., "AGC EL 550S") (2) Low molecular weight polyol 2: Polyether polyol (OHV: 450 mg KOH / g, f=4) (manufactured by AGC Inc., "AGC EL 450ED") (3) Hydroxylated cyclic carbonates: Glycerol carbonates (4) Resinization catalyst: N,N-dimethylcyclohexylamine (DMCHA) (5) Trimerization catalyst: Potassium octylate (6) Foam stabilizer: Silicone foam stabilizer (manufactured by Dow Toray Ltd., "SH-193") (7) Flame retardant: Tris(1-chloro-2-propyl) phosphate (TMCPP) (manufactured by Daihachi Chemical Industry Co., Ltd.)

[0114] [1.2.2. B liquid] The following ingredients are used for solution B. (8) Polyisocyanate: Crude MDI (manufactured by Tosoh Corporation, "MR-200")

[0115] [1.2.3. Hydrocarbons] The following materials were used as raw materials for the hydrocarbons. (9) Hydrocarbons: Cyclopentane (Marukazol FH, manufactured by Maruzen Petroleum Co., Ltd.)

[0116] [1.3. Preparation of insulation material (laminate board)] First, the above-mentioned liquid A was mixed in a predetermined ratio and stirred for 30 seconds using a 3000 rpm propeller agitator. Next, solution A was adjusted to 15°C, and solution B, which had also been adjusted to 15°C, was added to solution A to obtain a mixture. Next, hydrocarbons were added to the mixture to obtain the raw material composition. Next, the raw material composition was stirred for 10 seconds using a 5000 rpm propeller agitator. Next, the raw material composition was poured into a 300mm x 300mm x 50mm mold with polyethylene / kraft paper / polyethylene facing material on the top and bottom, and a 300mm x 300mm x 50mm laminate board with facing material on the top and bottom surfaces was produced (molded foaming).

[0117] [2. Test Method] [2.1. Closed-cell ratio] The percentage of closed cells was measured in accordance with ASTM D2856.

[0118] [2.2. Core Density] Core density was measured in accordance with JIS A9521. Core density was measured by excluding the 5mm portion containing the facing material from both the front and back surfaces of the laminate board.

[0119] [2.3. Nulate conversion rate] The "nurating rate" was calculated according to equation (i).

[0120] [2.4. Change rate of thermal conductivity] The "rate of change in thermal conductivity" was calculated according to equation (ii). However, the thermal conductivity was measured in a laminate board state with facing materials on the top and bottom surfaces, and the laminate board was stored in a 60°C constant temperature chamber. The thermal conductivity was measured using a thermal conductivity meter manufactured by Eiko Seiki Co., Ltd.

[0121] [3. Results] The results are shown in Tables 1 and 2. The raw material composition for each sample is also shown. Note that the raw material composition values ​​are expressed in mass percentage.

[0122] [Table 1]

[0123] [Table 2]

[0124] (1) In Comparative Example 1, the rate of change in thermal conductivity exceeded 6.0%. This is thought to be because the cell was not under pressure in its initial state due to the absence of hydroxylated cyclic carbonate. In Comparative Example 2, the rate of change in thermal conductivity exceeded 4.0%. In this case as well, this is thought to be because the cell was not under pressure in its initial state due to the absence of hydroxylated cyclic carbonate. (2) In Examples 1 to 3, the rate of change in thermal conductivity improved (the rate of change in thermal conductivity decreased) with increasing amounts of hydroxylated cyclic carbonate. This is thought to be because the initial state of the cell becomes more pressurized as the amount of hydroxylated cyclic carbonate added increases. Similarly, in Example 4, since a predetermined amount of hydroxylated cyclic carbonate is added, it is presumed that the initial state of the cell is also pressurized.

[0125] Although embodiments of the present invention have been described in detail above, the present invention is not limited in any way to the above embodiments, and various modifications are possible without departing from the spirit of the present invention. [Industrial applicability]

[0126] The rigid polyurethane foam according to the present invention can be used as insulation material for houses and the like.

Claims

1. A polyurethane foam obtained from a raw material composition containing a hydrated cyclic carbonate and a hydrocarbon.

2. The polyurethane foam according to claim 1, wherein the content of the hydrocarbon in the raw material composition is greater than the content of the hydroxylated cyclic carbonate. however, The term "hydrocarbon content" refers to the mass ratio of the hydrocarbon to the total mass of the raw material composition. The term "content of hydroxylated cyclic carbonate" refers to the ratio of the mass of the hydroxylated cyclic carbonate to the total mass of the raw material composition.

3. The content of the hydrocarbon is 1.0% by mass or more and 10.0% by mass or less. The polyurethane foam according to claim 2, wherein the content of the hydrated cyclic carbonate is 0.01% by mass or more and 5.0% by mass or less.

4. The polyurethane foam according to claim 1, wherein the water content in the raw material composition is 0.5% by mass or less. however, The term "water content" refers to the ratio of the mass of water to the total mass of the raw material composition.

5. The polyurethane foam according to claim 1, wherein the rate of change in thermal conductivity is 4.0% or less.

6. An insulating material comprising the polyurethane foam described in claim 1.

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