JP7749306B2 - Polyol chemical composition - Google Patents

Description

The present invention relates to a polyol liquid chemical composition, and in particular to a polyol liquid chemical composition for polyurethane foam that can be safely stored even in high-temperature environments.

Traditionally, polyurethane foams have been used primarily as insulating materials, taking advantage of their excellent insulating properties, adhesiveness, and light weight. These include insulating interior and exterior building wall materials and panels, insulating metal siding and electric refrigerators, insulating and preventing condensation on the walls, ceilings, and roofs of buildings, condominiums, and cold storage warehouses, and insulating infusion pipes. They are also used as backfill materials to fill voids that occur during civil engineering work and as reinforcing materials during civil engineering work. Such polyurethane foams are generally produced by continuously or intermittently mixing, in a mixing device, composition A, which consists of a polyol blend liquid (premix liquid) containing a polyol, a blowing agent, and, if necessary, various auxiliary agents such as catalysts, foam stabilizers, and flame retardants, with composition B, which primarily contains polyisocyanate, to form a foamable polyurethane foam composition. This foam is then foamed and cured using methods such as slab foaming, injection foaming, spray foaming, laminate continuous foaming, lightweight embankment construction, and injection backfill construction.

In addition, to produce such polyurethane foams, various compounds have been incorporated as blowing agents into the polyol liquid mixtures described above, which are polyol liquid chemical compositions. Examples of such compounds are disclosed in, for example, JP-A-7-97472, JP-A-2008-266569, and JP-A-2018-70708. Among these, hydrofluorocarbon (HFC) blowing agents such as HFC-134a, HFC-245fa, and HFC-365mfc, which are considered to have relatively high global warming potential, are known to be suitable blowing agents. These hydrofluorocarbon blowing agents are recognized as alternatives to fluorocarbons that cause little or no ozone layer depletion. However, it is expected that the use of such alternatives will be restricted in the near future due to strong demands to address environmental issues. As a result, alternative blowing agents have been developed that are chemically unstable and therefore have a low global warming potential, such as halogenated hydroolefins (halogenated alkenes) called hydrofluoroolefins (HFOs) and hydrochlorofluoroolefins (HCFOs), as well as hydrocarbons (HCs) such as pentane and cyclopentane.

After production, polyol chemical compositions containing the above-mentioned blowing agents are generally stored outdoors in containers such as drums. However, if the boiling point of the added blowing agent is lower than 35°C, and the container containing the polyol chemical composition is exposed to a high-temperature environment, such as when stored outdoors in the summer, the ambient temperature may reach 35°C or higher, causing the polyol chemical composition to boil inside the container. Furthermore, when such a container is opened, there is a risk of the polyol chemical composition bumping, or the blowing agent evaporating, resulting in degradation of the polyol chemical composition. Furthermore, there is also the inherent risk of the polyol chemical composition leaking from the container and causing contamination of the surrounding soil. In particular, solid substances or materials such as red phosphorus are added to polyol chemical compositions to improve the properties of the polyurethane foam formed by reaction with polyisocyanate. In such cases, these solid substances act as bubble points, making the polyol chemical composition more likely to boil in the container.

Japanese Patent Application Publication No. 7-97472 Japanese Patent Application Laid-Open No. 2008-266569 Japanese Patent Application Laid-Open No. 2018-70708

The present invention was made against this backdrop, and the problem to be solved is to provide a polyol liquid chemical composition that can be safely stored even in high-temperature environments without boiling or bumping, and also to provide a polyol liquid chemical composition that can be stored in a container and conveniently stored outdoors in direct sunlight during the summer.

In order to solve the above-mentioned problems, the present invention can be suitably implemented in various aspects as listed below, and the aspects described below can be employed in any combination. It should be understood that the aspects and technical features of the present invention are not limited to those described below, but can be recognized based on the description of the entire specification and the inventive ideas disclosed therein.

(1) A polyol composition that forms polyurethane foam by reaction with polyisocyanate, characterized in that it contains, as a blowing agent, at least a low-boiling blowing agent having a boiling point of less than 35°C together with a liquid polyol, and the content of the low-boiling blowing agent is not more than the solubility in the polyol, so that the low-boiling blowing agent is dissolved in the polyol.
(2) The polyol liquid chemical composition according to the above aspect (1), wherein the low-boiling point blowing agent is selected from the group consisting of hydrocarbons, hydrofluorocarbons, and halogenated alkenes.
(3) The polyol liquid chemical composition according to the above aspect (1) or (2), characterized in that, as the blowing agent, another blowing agent having a boiling point of 35°C or higher is contained together with the low-boiling-point blowing agent.
(4) The above-mentioned embodiment ( ) is characterized in that the foaming agent is contained in a total amount of 10 to 40 parts by mass per 100 parts by mass of the polyol.
The polyol chemical composition according to any one of aspects (1) to (3).
(5) The polyol chemical composition according to any one of the aspects (1) to (4), wherein the polyol is an aromatic polyester polyol.
(6) The polyol chemical composition according to any one of the aspects (1) to (5), wherein the polyol is a combination of an aromatic polyester polyol and a polyether polyol.
(7) The polyol chemical composition according to any one of the above aspects (1) to (6), further comprising a nonionic surfactant.
(8) The polyol chemical composition according to any one of the aspects (1) to (7), wherein the nonionic surfactant is contained in an amount of 5 to 30 parts by mass per 100 parts by mass of the polyol.
(9) The polyol chemical composition according to any one of the above aspects (1) to (8), further comprising a flame retardant.
(10) The polyol liquid chemical composition according to the above aspect (9), wherein the flame retardant is a solid substance.
(11) The polyol chemical composition according to any one of the aspects (1) to (10), characterized in that the viscosity at 20°C is 80 to 600 mPa·s.

In this way, the polyol liquid chemical composition according to the present invention uses a low-boiling-point blowing agent with a boiling point below 35°C as the blowing agent. Even when this is blended with a liquid polyol, the low-boiling-point blowing agent is used in a proportion below its solubility in the polyol, allowing the low-boiling-point blowing agent to be completely dissolved in the polyol. This makes it possible to raise the boiling point of the polyol liquid chemical composition as a whole. As a result, when such a polyol liquid chemical composition is stored in a container such as a drum and outdoors in direct sunlight during the summer, it is possible to effectively prevent the low-boiling-point blowing agent in the polyol liquid chemical composition from boiling due to an increase in temperature. It also makes it possible to advantageously prevent the polyol liquid chemical composition stored in the container from bumping due to changes in pressure when the container is opened.

Furthermore, in the polyol liquid chemical composition according to the present invention, the low-boiling point blowing agent used as the blowing agent is present in a form that is fully dissolved in the liquid polyol. This effectively prevents the polyol liquid chemical composition from boiling even at ambient temperatures higher than the boiling point of the low-boiling point blowing agent contained in the polyol liquid chemical composition, and advantageously prevents or suppresses cloudiness of the liquid chemical composition due to insufficient solubility of the low-boiling point blowing agent in the polyol. This effectively improves the long-term storage stability of the polyol liquid chemical composition and also enables the advantageous maintenance of the long-term physical properties of the polyurethane foam formed by the reaction with polyisocyanate.

Furthermore, by further incorporating a nonionic surfactant in the polyol liquid chemical composition according to the present invention in addition to the polyol and low-boiling-point blowing agent, the solubility of the low-boiling-point blowing agent in the polyol can be effectively improved, making it possible to prepare a more uniform polyol liquid chemical composition, thereby further increasing the boiling temperature of the polyol liquid chemical composition.

In addition, even if a specific solid substance is added to the polyol liquid chemical composition according to the present invention, the solid substance acts as a bubble point, effectively preventing the polyol liquid chemical composition from boiling in the container.

The specific composition of the polyol chemical composition according to the present invention will be described in more detail below.

First, the polyol liquid composition according to the present invention is primarily composed of a liquid polyol. The desired polyurethane foam is produced by reacting the polyol with a specific polyisocyanate and foaming with a blowing agent containing at least a low-boiling blowing agent having a boiling point of less than 35°C. The liquid polyol used therein may be any of a variety of known liquid polyol compounds, such as polyester polyols, polyether polyols, polyolefin polyols, acrylic polyols, and polymer polyols, used alone or in appropriate combinations. Of these, polyester polyols are preferred for use in the present invention. The total proportion of polyol in the polyol liquid composition is generally approximately 50 to 90% by mass, and preferably approximately 60 to 85% by mass.

Among the polyols mentioned above, polyester polyols that are preferably used include known polyols such as polyhydric alcohol-polycarboxylic acid condensation polyols and cyclic ester ring-opening polymer polyols. Examples of polyhydric alcohols that can be used include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, and pentaerythritol. Examples of polycarboxylic acids that can be used include succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, terephthalic acid, isophthalic acid, and anhydrides thereof. Examples of cyclic esters include ε-caprolactone.

Among the polyester polyols listed above, aromatic polyester polyols are preferred in the present invention from the viewpoint of improving compatibility with low-boiling blowing agents and the flame retardancy of the resulting polyurethane foam. Specifically, phthalic acid-based polyester polyols are preferred, and combining two or more of these polyester polyols is also effective. Phthalic acid-based polyester polyols composed of condensates of phthalic acid, terephthalic acid, isophthalic acid, or anhydrides thereof with dihydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol are preferred. Such aromatic polyester polyols are preferably used in a proportion of 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more, of the polyol.

In addition, polyether polyols are also suitable for use as polyols in the present invention, and their use in combination with the aromatic polyester polyols described above is particularly recommended. The use of such polyether polyols advantageously enhances the physical properties, such as strength, of the polyurethane foam formed by reaction with polyisocyanate. The polyether polyols used here are obtained by reacting alkylene oxide with at least one initiator, such as a polyhydric alcohol, sugar, aliphatic amine, aromatic amine, phenol, or Mannich condensation product. Examples of alkylene oxides include propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, and ethylene oxide. Polyhydric alcohols usable as initiators include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc.; sugars include sucrose, dextrose, sorbitol, etc.; aliphatic amines include alkanolamines such as diethanolamine and triethanolamine, and polyamines such as ethylenediamine; aromatic amines include various methyl-substituted phenylenediamines, collectively known as tolylenediamine, as well as derivatives in which substituents such as methyl, ethyl, acetyl, and benzoyl have been introduced into the amino group, 4,4'-diaminodiphenylmethane, p-phenylenediamine, o-phenylenediamine, and naphthalenediamine; and phenols include bisphenol A and novolac-type phenolic resins. Mannich condensation products include those obtained by the Mannich condensation reaction of phenols, aldehydes, and alkanolamines.

The polyol liquid chemical composition according to the present invention contains, in addition to the liquid polyol described above, at least one blowing agent, a low-boiling blowing agent with a boiling point of less than 35°C. Such a low-boiling blowing agent can be appropriately selected from various known non-fluorocarbon and fluorocarbon blowing agents with a boiling point of less than 35°C. In particular, organic low-boiling blowing agents belonging to halogenated alkenes, such as hydrocarbons (HCs) and hydrofluorocarbons (HFCs), as well as hydrofluoroolefins (HFOs) and hydrochlorofluoroolefins (HCFOs), are advantageously used in the present invention.

Specific examples of hydrocarbons (HCs) that are non-fluorocarbon blowing agents include isopentane, and examples of hydrofluorocarbons (HFCs) that are fluorocarbon blowing agents include 1,1,1,3,3-pentafluoropropane (HFC245fa). Furthermore, examples of hydrofluoroolefins (HFOs) include pentafluorobutene isomers (HFO1354), hexafluorobutene isomers (HFO1336) such as 1,1,1,4,4,4-hexafluoro-2-butene (HFO1336mzz), heptafluoropentene isomers (HFO1447), and octafluoropentene isomers (HFO1438). Additionally, examples of hydrochlorofluoroolefins (HCFOs) include 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), and 1-chloro-2,3,3-tetrafluoropropene (HCFO-1224yd).

Of the low-boiling-point blowing agents mentioned above, hydrofluoroolefins (HFOs) and hydrochlorofluoroolefins (HCFOs) are particularly chemically unstable and have low global warming potentials, making them suitable for use as environmentally friendly blowing agents. Furthermore, in order to improve ease of handling as a blowing agent and to further enjoy the effects of the present invention, it is generally desirable for the lower limit of the boiling point of the low-boiling-point blowing agents mentioned above to be around 10°C.

Such low-boiling blowing agents are used in a proportion that is equal to or less than their solubility in the polyol that constitutes the polyol chemical composition to which they are added. This allows the low-boiling blowing agent to be completely dissolved in the polyol, resulting in a chemical composition that can be safely stored even in high-temperature environments without problems such as boiling or bumping. The solubility of such low-boiling blowing agents varies depending on the type of low-boiling blowing agent and the type of polyol that constitutes the polyol chemical composition. Therefore, the solubility of the low-boiling blowing agent added is determined at 25°C for the polyol used, and the low-boiling blowing agent is added to the polyol chemical composition in a proportion that is equal to or less than that solubility. When a polyol chemical composition is prepared using multiple types of polyols, the solubility of the low-boiling blowing agent in a mixture of the multiple types of polyols is used, and the low-boiling blowing agent is added in a proportion that is equal to or less than that solubility.

In addition, in the present invention, in addition to using only the low-boiling blowing agents described above as the blowing agent contained in the polyol liquid chemical composition, other blowing agents with boiling points different from those of the low-boiling blowing agents, i.e., boiling points of 35°C or higher, can also be selected from a variety of known blowing agents and used together with such low-boiling blowing agents. In such cases, organic blowing agents such as high-boiling (boiling points of 35°C or higher) hydrocarbons (HCs), high-boiling hydrofluorocarbons (HFCs), high-boiling hydrofluoroolefins (HFOs), and high-boiling hydrochlorofluoroolefins (HCFOs) are advantageously selected as the other blowing agents. Specifically, n-pentane, 1,1,1,3,3-pentafluorobutane (HFC365mfc), isopropyl chloride, etc. are advantageously selected as the other blowing agents.

Furthermore, in the present invention, water is advantageously used as a blowing agent together with the low-boiling blowing agent described above, or together with the low-boiling blowing agent and other blowing agents. Thus, the presence of water in the polyol chemical composition allows the polyol chemical composition and the polyisocyanate (composition) to be mixed and reacted. When the water reacts with the polyisocyanate to produce carbon dioxide, reaction heat is generated. This heat effectively promotes the urethanization reaction and the isocyanurate reaction, further increasing the compressive strength of the resulting polyurethane foam. Furthermore, the presence of water in the polyol chemical composition allows the carbon dioxide generated during the reaction with the polyisocyanate to contribute to polyurethane foaming.

The amount of water used is generally selected to be 0.5 to 8 parts by mass, preferably 1 to 5 parts by mass, per 100 parts by mass of the total polyol in the polyol chemical composition. If the amount of water used exceeds 8 parts by mass per 100 parts by mass of the total polyol, the strength of the resulting polyurethane foam will actually decrease. This is because the urea bonds formed by the reaction between water and polyisocyanate increase in the resin, and the polyisocyanate used in the isocyanurate reaction is consumed in the reaction with water, leaving less polyisocyanate in the reaction system. On the other hand, if the amount of water used is less than 0.5 parts by mass, the effect of the water as a blowing agent will not be fully achieved.

The total content of blowing agents, including the low-boiling blowing agent, in the polyol liquid chemical composition according to the present invention is determined appropriately taking into account the solubility of the low-boiling blowing agent. Generally, it is desirable that the content be 10 to 40 parts by mass, and preferably 15 to 35 parts by mass, per 100 parts by mass of the total polyol in the polyol liquid chemical composition. If the total amount of blowing agent is too low, the foaming characteristics will deteriorate, leading to problems such as insufficient foaming during spray foaming. On the other hand, if the total amount of blowing agent is too high, problems such as the polyol liquid chemical composition being prone to boiling in high-temperature environments will arise.

In addition, the polyol liquid chemical composition according to the present invention preferably contains a nonionic surfactant in addition to the polyol and low-boiling-point blowing agent described above. This nonionic surfactant functions as a compatibilizer between the polyol and the low-boiling-point blowing agent. By including such a nonionic surfactant, the solubility of the low-boiling-point blowing agent in the polyol can be further improved, allowing the low-boiling-point blowing agent to be easily and completely dissolved in the polyol, thereby providing the advantage of increasing the boiling temperature of the polyol liquid chemical composition.

The nonionic surfactants used herein include, for example, ether-type surfactants such as polyoxyethylene alkyl ether, polyoxyethylene lauryl ether, polyoxyalkylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene polyoxypropylene monobutyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene nonylphenyl ether, and polyoxyethylene polyoxypropylene monobutyl ether; polyoxyethylene oleate, glycerin fatty acid ester, polyoxyethylene stearic acid ester, polyoxyethylene fatty acid (lauryl) methyl ester, and polyethylene glycol oleate monoester. Examples of suitable olefins include ester-ether types such as polyoxyethylene sorbitan fatty acid esters and polyoxyethylene alkyl esters; ester types such as polyoxyethylene alkyl esters, sucrose fatty acid esters, and sorbitan fatty acid esters; alkyl glycosides such as octyl glucoside; alkanolamide types such as polyoxyethylene oleic acid amide and polyoxyethylene alkylamide; amine oxides such as dodecyl dimethylamine oxide and tetradecyl dimethylamine oxide; alkylamine types such as polyoxyethylene alkylamines and polyoxypropylene polyoxyethylene alkylamines; higher alcohols such as cetanol, stearyl alcohol, and oleyl alcohol; and polyoxyethylene distyrenated phenyl ether. Among these, polyoxyalkylene alkyl ethers are particularly preferred in the present invention due to their low freezing point and good affinity.

The amount of nonionic surfactant used will be determined appropriately depending on the type of polyol and low-boiling blowing agent, the amount of low-boiling blowing agent used, and other factors, but it is generally used in an amount of 5 to 30 parts by mass, and preferably 8 to 25 parts by mass, per 100 parts by mass of the total polyol in the polyol liquid composition. If the amount of nonionic surfactant used is less than 5 parts by mass, the compatibility-improving effect will not be fully exerted, and if it exceeds 30 parts by mass, the foam properties of the polyurethane foam formed by reaction with the polyisocyanate will deteriorate.

Furthermore, various known flame retardants may be added to the polyol liquid composition of the present invention to impart the required flame retardancy to the polyurethane foam formed by reaction with polyisocyanate. The flame retardant used here is not particularly limited, and either liquid or solid flame retardants are acceptable. However, the features of the present invention are advantageously exhibited when a solid flame retardant is used. When the flame retardant is a solid substance such as a powder or granule, such a solid substance acts as a zeolite, making the polyol liquid composition prone to boiling and bumping, resulting in a lower boiling point. However, according to the present invention, by dissolving a low-boiling point blowing agent in the polyol at a ratio below its solubility in the polyol, particularly when a nonionic surfactant is present, the composition can maintain a high boiling point without lowering the boiling point, even when such a solid flame retardant is included, while also exhibiting the characteristic of further improving flame retardancy.

Such solid flame retardants include known compounds such as red phosphorus, phosphate-containing flame retardants, boron-containing flame retardants, metal stannate-containing flame retardants, and metal hydroxides. These flame retardants are generally blended in an amount of 5 to 60 parts by weight, and preferably 10 to 40 parts by weight, per 100 parts by weight of the total polyol in the polyol liquid composition.

In addition to the above-mentioned components, known catalysts and foam stabilizers may also be added to the polyol chemical composition of the present invention, as needed. The catalyst promotes the reaction between the polyol and polyisocyanate in the polyol chemical composition and can be selected from a variety of known catalysts. For example, well-known amine catalysts and imidazole catalysts may be used alone or in combination. Furthermore, urethane catalysts and isocyanurate catalysts may also be used in combination with such catalysts as needed. Examples of urethanization catalysts include dibutyltin dilaurate, fatty acid bismuth salts such as bismuth octoate (bismuth 2-ethylhexyl), bismuth neodecanoate, bismuth neododecanoate, and bismuth naphthenate, lead naphthenate, and lead octoate (lead 2-ethylhexyl). Examples of isocyanuration catalysts include quaternary ammonium salts; fatty acid alkali metal salts such as potassium octoate and sodium acetate; and tris(dimethylaminopropyl)hexahydrotriazine. These various catalysts are typically used in an amount of 0.1 to 7 parts by weight, and preferably 0.5 to 5 parts by weight, per 100 parts by weight of the total polyol in the polyol chemical composition.

The foam stabilizer is used to uniformly adjust the cell structure of the polyurethane foam and is appropriately selected from known foam stabilizers. Specific examples include polyoxyalkylene-modified dimethylpolysiloxane, polysiloxane oxyalkylene copolymer, polyoxyethylene sorbitan fatty acid ester, castor oil ethylene oxide adduct, and lauryl fatty acid ethylene oxide adduct. One of these may be used alone, or two or more may be used in combination. The amount of foam stabilizer to be added is determined appropriately depending on the desired foam characteristics and the type of foam stabilizer used, but is generally selected within the range of 0.1 to 10 parts by weight, preferably 1 to 8 parts by weight, per 100 parts by weight of the total polyol in the polyol chemical composition.

In addition, the polyol chemical composition of the present invention can also contain various conventionally known additives, such as formaldehyde scavengers such as urea and melamine, bubble-refining agents, plasticizers, and reinforcing substrates, as needed.

The polyisocyanate reacted with the polyol chemical composition of the present invention reacts with the polyol in the polyol chemical composition to produce polyurethane (resin). It is an organic isocyanate compound having two or more isocyanate groups (NCO groups) in its molecule. Examples include aromatic polyisocyanates such as diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate, tolylene diisocyanate, polytolylene triisocyanate, xylylene diisocyanate, and naphthalene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; alicyclic polyisocyanates such as isophorone diisocyanate; urethane prepolymers having isocyanate groups at the molecular terminals; isocyanurate-modified polyisocyanates; and carbodiimide-modified polyisocyanates. These polyisocyanate compounds may be used alone or in combination of two or more. Generally, polymethylene polyphenylene polyisocyanate (polymeric MDI) is preferred from the standpoints of reactivity, economy, ease of handling, etc. However, such polyisocyanates can also be used in the form of a composition in which various conventionally known auxiliary agents are appropriately blended, as needed.

The polyol liquid chemical composition containing the specified components according to the present invention can be produced by various conventional methods. Generally, however, it is prepared by mixing a polyol with a blowing agent containing a specified low-boiling-point blowing agent, and then, as necessary, adding a nonionic surfactant, catalyst, foam stabilizer, and other additives to form a homogeneous mixture. This is then used as a premix liquid and reacted with a polyisocyanate. When a nonionic surfactant is added, it is advantageous to first mix the nonionic surfactant with the polyol, and then mix the low-boiling-point blowing agent and other ingredients. Mixing the nonionic surfactant with the polyol first facilitates the subsequent mixing of the low-boiling-point blowing agent and the polyol through the surfactant. In this way, by adding and mixing a blowing agent, including a low-boiling point blowing agent, with a polyol in the presence of a nonionic surfactant, the compatibility between the polyol and the blowing agent can be effectively increased.

The polyol chemical composition prepared in this manner desirably has a viscosity at 20°C of 80 to 600 mPa·s, preferably 100 to 550 mPa·s, and more preferably 150 to 500 mPa·s. If the viscosity is lower than 80 mPa·s, problems such as the chemical composition being prone to boiling may arise, while if the viscosity is higher than 600 mPa·s, problems such as the chemical composition being prone to bumping may arise.

The polyol liquid chemical composition according to the present invention obtained as described above is then mixed with polyisocyanate and foamed and cured to produce the desired polyurethane foam. Various known polyurethane foam production techniques can be used, including, for example, the laminate continuous foaming method, in which a mixture of the polyol liquid chemical composition and polyisocyanate is applied to a surface material and foamed and cured into a plate; the injection foaming method, in which the mixture is injected and filled into spaces requiring insulation, such as electric refrigerators, or into the honeycomb structure of lightweight, high-strength boards, and foamed and cured; and the spray foaming method, in which the foamable composition according to the present invention is sprayed from the spray gun head of an on-site foaming machine onto a specified substrate (structure), foaming and curing, to form the desired polyurethane foam.

In particular, the polyol liquid chemical composition according to the present invention can be safely stored even in high-temperature environments without causing problems such as boiling or bumping. Therefore, even if the composition is placed in a container such as a drum prior to use in the above-mentioned applications and placed outdoors in direct sunlight in the summer, for example, boiling of the blowing agent can be advantageously suppressed or prevented. This advantageously avoids problems such as bumping of the liquid chemical due to changes in air pressure when a container such as a drum is opened, and also makes it possible to advantageously store the polyol liquid chemical composition for long periods of time and maintain the long-term physical properties of the polyurethane foam formed.

Below, several examples of the present invention will be presented and compared with comparative examples to further clarify the features of the present invention. However, it goes without saying that the present invention is in no way limited by the description of such examples. Furthermore, it should be understood that in addition to the examples below and the specific description above, various changes, modifications, improvements, etc. can be made to the present invention based on the knowledge of those skilled in the art, as long as they do not deviate from the spirit of the present invention. Furthermore, unless otherwise specified, percentages (%) and parts shown below are all expressed on a mass basis.

In addition, the viscosity, foaming property, boiling property, and turbidity of the polyol liquid chemical compositions obtained in the following examples and comparative examples were evaluated as follows.

(1) Viscosity Measurement: Measurement is carried out in accordance with JIS-K-7117-1 (1999) at a measurement temperature of 20°C using a Brookfield rotational viscometer, model B.

(2) Evaluation of Foamability The polyol liquid chemical compositions prepared in the following Examples and Comparative Examples were used as test solutions, filled into sealable transparent glass bottles, sealed, and then heated in a hot water bath at temperatures of 30°C, 35°C, 38°C, or 40°C for 30 minutes.The test solutions were then removed from the hot water bath and the lids of the glass bottles were opened, and the foaming state of the test solutions was visually observed.The foamability of each test solution was evaluated according to the following criteria, and a rating of "○" or higher was considered a pass.
◎: The test solution does not foam.
○: Some bubbles were observed in the test solution.
△: The test liquid does not overflow from the glass bottle, but is quite foamy.
×: The test solution foams and overflows from the glass bottle.

(3) Evaluation of boiling property Each test liquid was placed in a beaker and heated in a hot water bath at 35°C for 30 minutes, and the test liquid in the beaker was visually observed to see if it boiled. If the test liquid in the beaker was not boiling, it was evaluated as "○", if it was about to boil, it was evaluated as "△", and if it was boiling, it was evaluated as "×". Of these evaluations, "○" was considered to be a pass.

(4) Evaluation of Turbidity Each test solution is weighed out so that the total volume is 100 ml, and left to stand for 10 minutes in an atmosphere of 25° C., after which the turbidity of the weighed test solution is evaluated visually. The visual evaluation is carried out by 10 panelists according to the following evaluation criteria, and the obtained evaluation levels are averaged to evaluate the merits and demerits.
⊚: No turbidity was observed in the test solution.
○: Almost no turbidity was observed in the test solution.
△: The test solution is slightly cloudy.
×: The test solution is observed to be cloudy.

First, the following raw materials were prepared as components used in the following Examples and Comparative Examples. Note that the solubility of the blowing agent was determined at 25°C.
Polyisocyanate: Polymeric MDI (Wannate PM-130 manufactured by Wanka Chemical Japan Co., Ltd.)
Polyol: terephthalic acid-based polyester polyol (RFK 505 manufactured by Kawasaki Chemical Industries, Ltd.)
(HCFO-1233zd solubility: 35 g/100 g - polyol
HFO-1336mzz solubility: 5g/100g-polyol
HFC245fa solubility: 20g/100g-polyol
HFC365mfc solubility: 10g/100g-polyol
Water solubility: 20g/100g-polyol)
Polyol: isophthalic acid-based polyester polyol (RDK 142 manufactured by Kawasaki Chemical Industries, Ltd.)
(HCFO-1233zd solubility: 25g/100g-polyol
HFO-1336mzz solubility: 15g/100g-polyol
Water solubility: 55g/100g-polyol)
Polyol: Polypropylene glycol (GP1000 manufactured by Sanyo Chemical Industries, Ltd.)
(HCFO-1233zd solubility: 40 g or more/100 g-polyol
Water solubility: 100g or more/100g-polyol)
Foam stabilizer: Silicone foam stabilizer (SH-193 manufactured by Toray Dow Corning Co., Ltd.)
Catalyst: Alkali metal carboxylate catalyst (Pucat 15G, potassium octylate, manufactured by Nippon Chemical Industry Co., Ltd.)
Catalyst: Imidazole catalyst (Kao Raiser No. 390 manufactured by Kao Corporation, 1,2-dimethylimidazole:dipropylene glycol = 70:30 [mass ratio])
Nonionic surfactant: Polyoxyalkylene alkyl ether (Emulgen LS106 manufactured by Kao Corporation)
Nonionic surfactant: Polyoxyalkylene alkyl ether (Emulgen LS110 manufactured by Kao Corporation)
Nonionic surfactant: nonylphenol polyethylene glycol ether (Tergitol NP-9 manufactured by The Dow Chemical Company)
Flame retardant: Red phosphorus (Nova Excel 140, powder, manufactured by Rinkagaku Kogyo Co., Ltd.)
Flame retardant: Phosphate (Fujifilm Wako Pure Chemical Industries, Ltd., ammonium dihydrogen phosphate, powder)
Flame retardant: phosphate ester [manufactured by Daihachi Chemical Industry Co., Ltd., TMCPP: tris(1-chloro-2-propyl)phosphate, liquid]
Blowing agent: HCFO-1233zd (manufactured by Honeywell, 1-chloro-3,3,3-trifluoropropene, boiling point 18.3°C)
Blowing agent: HFO-1336mzz (manufactured by Chemours, 1,1,1,4,4,4-hexafluoro-2-butene, boiling point 33.4°C)
Blowing agent: HFC245fa (manufactured by Central Glass Co., Ltd., 1,1,1,3,3-pentafluoropropane, boiling point 15.3°C)
Blowing agent: HFC365mfc (manufactured by SOLVAY Corporation, 1,1,1,3,3-pentafluorobutane, boiling point 40.2°C)
Foaming agent: Water

The various raw materials prepared above, namely, polyol, blowing agent, foam stabilizer, catalyst, nonionic surfactant, and flame retardant, were uniformly mixed in the various combinations and blending ratios shown in Tables 1 to 3 below to prepare various polyol liquid compositions according to Examples 1 to 14 and Comparative Examples 1 to 6. When blending in a nonionic surfactant, the nonionic surfactant was first blended with the polyol and mixed uniformly, after which other additives such as the blowing agent were blended in.

The various polyol liquid chemical compositions thus obtained were used as test liquids and evaluated for their foaming, boiling, and turbidity. The results are summarized in Tables 1 to 3 below.

As is clear from the results in Tables 1 and 2, the polyol liquid chemical compositions prepared in Examples 1 to 14 according to the present invention were all found to have excellent resistance to foaming, boiling, and turbidity. In particular, the polyol liquid chemical compositions of Examples 8 to 11, which further contain a nonionic surfactant, were found to have even better resistance to foaming and turbidity. These results indicate that the polyol liquid chemical compositions prepared in Examples 1 to 14, even when stored in a container such as a drum and exposed to a high-temperature environment, for example, outdoors in direct sunlight in the summer, are prevented from causing problems such as boiling in the container or bumping when the container is opened. Furthermore, it is believed that the risk of deterioration of the properties of the liquid chemical composition due to vaporization of the blowing agent can also be advantageously avoided.

In contrast, as is clear from the results shown in Table 3, in the polyol liquid chemical compositions prepared in Comparative Examples 1 to 6, the amount of blowing agent used was greater than the solubility of the blowing agent in the polyol that constitutes the polyol liquid chemical composition. As a result, the compositions tend to foam easily at high temperatures and have insufficient boiling and turbidity. Therefore, the polyol liquid chemical compositions of these Comparative Examples are likely to cause problems such as boiling and bumping in high-temperature environments, making them difficult to store safely.

- Flame retardancy evaluation -
The polyol chemical compositions containing the flame retardants prepared in Examples 12 to 14 were used, and the previously prepared polyisocyanate was applied to a 910 mm x 910 mm flexible board using a foaming machine (Graco A-25), with a base blow of 5 mm or less and then lamination to a thickness of 30 mm or less to produce foams with a total thickness of approximately 60 mm. In this spray foaming, the polyol chemical composition and the polyisocyanate were mixed in a volume ratio of 1:1.

The foams thus obtained were evaluated for flame retardancy in accordance with JIS-A-9511 (2017) combustion test method B. Specifically, a test piece measuring 50 mm × 150 mm × 13 mm was cut from each foam, and one end of the test piece was burned for 60 seconds using a Bunsen burner equipped with a fishtail light. The time until flame extinction and the burning distance were then measured, and the evaluation was based on the following criteria. The results are shown in Table 4 below.
⊚: Burning distance is less than 30 mm and burning time is less than 60 seconds.
Good: Burning distance is less than 60 mm and burning time is less than 120 seconds.
△: Burning distance is 60 mm or more or burning time is 120 seconds or more.
×: Burning distance is 60 mm or more and burning time is 120 seconds or more.

As is clear from the results in Table 4, the polyurethane foams obtained from all of the polyol liquid chemical compositions were found to have excellent flame retardancy. In particular, Examples 12 and 13 used powdered flame retardants, red phosphorus and phosphate, respectively. It can be seen that the inclusion of such powdered (solid) flame retardants did not result in any deterioration in the properties of the polyol liquid chemical composition.

Claims (11)

1. A polyol composition that forms a polyurethane foam upon reaction with a polyisocyanate, comprising:
A polyol liquid chemical composition comprising a liquid polyol and an imidazole catalyst (excluding imidazole compounds in which a secondary amine functional group in the imidazole ring is substituted with a cyanoethyl group), and further comprising, as a blowing agent, at least a low-boiling-point blowing agent consisting of a halogenated alkene having a boiling point of less than 35°C and water, wherein the content of the low-boiling-point blowing agent is not more than its solubility in the polyol and the low-boiling-point blowing agent is dissolved in the polyol, and the total content of the blowing agent including the low-boiling-point blowing agent and water is 15 to 35 parts by mass per 100 parts by mass of the polyol. 2. The polyol chemical composition according to claim 1 , wherein the foaming agent contains, in addition to the low-boiling point foaming agent and water, another foaming agent having a boiling point of 35[deg.] C. or higher. The polyol chemical composition according to claim 1 or 2, characterized in that water as the blowing agent is contained in an amount of 1 to 8 parts by mass per 100 parts by mass of the polyol. 4. The polyol chemical composition according to claim 1 , wherein the polyol is an aromatic polyester polyol. 4. The polyol chemical composition according to claim 1 , wherein an aromatic polyester polyol and a polyether polyol are used in combination as the polyol. 6. The polyol chemical composition according to claim 1, further comprising a nonionic surfactant. 7. The polyol chemical composition according to claim 6 , wherein the nonionic surfactant is contained in an amount of 5 to 30 parts by mass per 100 parts by mass of the polyol. 8. The polyol chemical composition according to claim 1 , further comprising a flame retardant. 9. The polyol chemical composition according to claim 8 , wherein the flame retardant is a solid substance. The polyol chemical composition according to any one of claims 1 to 9 , characterized in that the viscosity at 20°C is 80 to 600 mPa·s. The polyol chemical composition according to any one of claims 1 to 10 , further comprising a carboxylic acid alkali metal salt catalyst in addition to the imidazole catalyst.