JP7649109B2 - Polyol composition, polyurethane composition, and polyurethane foam - Google Patents

Description

The present invention relates to a polyol composition, a polyurethane composition comprising the polyol composition and a polyisocyanate composition, and a polyurethane foam formed from the polyurethane composition.

Conventionally, polyurethane foams have been used as heat insulating materials in vehicles such as automobiles, railway cars, and ships, buildings, etc. For polyurethane foams, two-component polyurethanes in which a polyol composition and a polyisocyanate composition filled in separate containers are mixed to form a foam are widely used.
Two-component polyurethanes are sometimes used in aerosol containers because each liquid can be discharged from a container with a relatively simple structure and mixed. When two-component polyurethanes are used in aerosol containers, one container is filled with a polyol compound and a low-boiling point compound, and the other container is filled with a polyisocyanate compound and a low-boiling point compound. Polyol liquid and polyisocyanate liquid are discharged from each container by the vapor pressure of the low boiling point, and they are mixed to form a polyurethane foam.

Low boiling point compounds used in aerosol containers include hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), dimethyl ether, liquefied petroleum gas, etc. Furthermore, since HFCs and HCFCs have a high global warming potential, there is a demand for alternative compounds to replace them.
For example, Patent Document 1 describes a two-liquid aerosol composition for rigid polyurethane foams that contains a specific amount of a low-boiling point compound, and describes that by using liquefied petroleum gas (LPG), dimethyl ether (DME), etc. as the low-boiling point compound, there is no adverse effect on global warming.

JP 2006-169474 A

However, aerosol containers are easily affected by the outside air temperature, and the polyol composition enclosed therein tends to become cold. This makes the curing reaction when forming polyurethane foam slow. In addition, the shape retention of the polyol composition before curing is poor, and as mentioned above, the curing speed is slow, so that liquid dripping occurs before curing, resulting in poor appearance of the polyurethane foam formed and dirt around the application site.

Therefore, the present invention aims to provide a polyol composition that has good shape retention and a fast curing rate when mixed with a polyisocyanate compound, a polyurethane composition containing the composition, and a polyurethane foam.

As a result of intensive investigations, the present inventors have found that the above-mentioned problems can be solved by a polyol composition containing a polyol compound containing an aromatic ring, a catalyst, and a low-boiling point compound having a boiling point of 0° C. or less, a polyurethane composition including the composition, and a polyurethane foam, and have completed the present invention as described below. That is, the present invention provides the following [1] to [10].
[1] A polyol composition comprising a polyol compound containing an aromatic ring, a catalyst, and a low-boiling point compound having a boiling point of 0°C or lower.
[2] The polyol composition according to the above [1], wherein the aromatic ring concentration of the aromatic ring-containing polyol compound is 5 to 30 mass%.
[3] The polyol composition according to [1] or [2] above, wherein the catalyst comprises a trimerization catalyst.
[4] The polyol composition according to any one of the above [1] to [3], wherein the catalyst comprises a trimerization catalyst and a resinification catalyst.
[5] The polyol composition according to any one of [1] to [4] above, having a shape retention rate calculated by the following formula (1) of 40% or more.
(Calculation of shape retention rate)
The polyol composition is poured into a container and the container is kept at 35° C., and then the polyol composition is discharged from the container into a plastic container having an inner diameter of 53 mm and a height of 72 mm so that the volume of the discharged liquid becomes equal to the volume of the plastic container. After 10 seconds have passed, the liquid level is measured and the shape retention rate is calculated based on the following formula (1).
Formula (1) Shape retention rate (%) = (liquid level after 10 seconds) ÷ (initial liquid level) × 100
[6] A container enclosing the polyol composition according to any one of [1] to [5] above.
[7] The container described in [6] above, which is an aerosol container.
[8] A polyurethane composition comprising the polyol composition according to any one of [1] to [5] above and a polyisocyanate composition containing a polyisocyanate compound.
[9] The polyurethane composition according to the above [8], having an isocyanate index of 200 to 1,000.
[10] A polyurethane foam formed from the polyurethane composition described in [9] above.

The present invention provides a polyol composition that has good shape retention and a fast curing rate when mixed with a polyisocyanate compound, a polyurethane composition containing the composition, and a polyurethane foam.

FIG. 1 is a schematic diagram illustrating one embodiment of a mixing system. FIG. 2 is a schematic diagram illustrating another embodiment of a mixing system.

The present invention will be described in detail below.
The present invention is a polyol composition comprising a polyol compound containing an aromatic ring, a catalyst, and a low-boiling compound having a boiling point of 0° C. or lower.

[Polyol compound]
The polyol composition of the present invention contains a polyol compound containing an aromatic ring. By containing a polyol compound containing an aromatic ring, the shape stability of the composition when the polyol composition is discharged from a container is improved. Therefore, the appearance defect of a polyurethane foam formed from the polyol composition is reduced.

The aromatic ring concentration of the polyol compound containing an aromatic ring is preferably 5 to 30% by mass, more preferably 10 to 30% by mass, and even more preferably 15 to 25% by mass. When the aromatic ring concentration is equal to or higher than these lower limits, the shape retention of the polyol composition is improved, and when the aromatic ring concentration is equal to or lower than these upper limits, the viscosity of the polyol composition is easily reduced, the handleability is improved, and the load when discharging from a container is reduced, making it easier to increase the amount of discharging.
The aromatic ring concentration of the polyol compound refers to the total mass % of carbon atoms and hydrogen atoms constituting the aromatic rings in the polyol compound.

Examples of polyol compounds containing an aromatic ring include aromatic polyols, aromatic polyester polyols, and aromatic polyether polyols. Among these, aromatic polyester polyols are preferred from the viewpoint of improving the shape stability of the polyol composition.

Examples of the aromatic polyols include bisphenol A, bisphenol F, benzene dimethanol, toluene dimethanol, and xylene dimethanol.

Examples of the aromatic polyester polyol include polymers having an aromatic ring obtained by dehydration condensation of a polybasic acid and a polyhydric alcohol, which are obtained by using at least one of the polybasic acid and the polyhydric alcohol having an aromatic ring.
Among the polybasic acids, those having an aromatic ring include o-phthalic acid (phthalic acid), m-phthalic acid (isophthalic acid), p-phthalic acid (terephthalic acid), naphthalenedicarboxylic acid, etc. Furthermore, among the polybasic acids, those not having an aromatic ring include, for example, aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, maleic acid, pimelic acid, suberic acid, azelaic acid, itaconic acid, sebacic acid, chlorendic acid, 1,2,4-butane-tricarboxylic acid, decanedicarboxylic acid, cyclohexanedicarboxylic acid, dimer acid, and fumaric acid.
Among the polyhydric alcohols, examples of those having an aromatic ring include aromatic diols such as benzene dimethanol, toluene dimethanol, xylene dimethanol, etc. Examples of those not having an aromatic ring include aliphatic polyols such as ethylene glycol, propylene glycol, 1,3-propylene diol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, neopentyl glycol, ethylene glycol, etc.

Among the aromatic polyester polyols described above, phthalic acid polyester polyols, which are condensates of phthalic acid and polyhydric alcohols, are preferred from the viewpoint of shape stability of the polyol composition. Examples of phthalic acid include o-phthalic acid (phthalic acid), m-phthalic acid (isophthalic acid), and p-phthalic acid (terephthalic acid).

The aromatic polyether polyol may, for example, be a polymer obtained by ring-opening polymerization of an alkylene oxide in the presence of an aromatic compound having two or more active hydrogens.
Examples of the aromatic compound having two or more active hydrogens include bisphenol A and bisphenol F. Examples of the alkylene oxide include ethylene oxide, propylene oxide, and tetrahydrofuran.

The hydroxyl value of the aromatic ring-containing polyol compound is preferably 20 to 300 mgKOH/g, more preferably 30 to 250 mgKOH/g, and even more preferably 50 to 220 mgKOH/g. When the hydroxyl value of the aromatic ring-containing polyol compound is equal to or less than the upper limit, the viscosity of the polyol composition is likely to decrease, which is preferable from the viewpoint of handleability, etc. On the other hand, when the hydroxyl value is equal to or more than the lower limit, the crosslink density of the polyurethane foam increases, thereby increasing the strength.
The hydroxyl value of the polyol compound can be measured in accordance with JIS K 1557-1:2007.

The content of the polyol compound containing an aromatic ring in the polyol composition of the present invention is preferably 10 to 90% by mass, more preferably 30 to 85% by mass, and even more preferably 40 to 80% by mass. If the content of the polyol compound is equal to or greater than the lower limit, it is preferable because it makes it easier for the polyol and the polyisocyanate to react with each other. On the other hand, if the content of the polyol compound is equal to or less than the upper limit, it is preferable from the viewpoint of handleability because the viscosity of the polyol-containing composition does not become too high.

The polyol composition may contain a polyol compound that does not contain an aromatic ring, in addition to the above-mentioned polyol compounds that contain an aromatic ring, within a range that does not impair the effects of the present invention. The content of the polyol compound that does not have an aromatic ring is preferably 20% by mass or less, more preferably 5% by mass or less, and even more preferably 0% by mass, based on the total amount of the polyol compounds contained in the polyol composition.

[catalyst]
The polyol composition of the present invention contains a catalyst. The catalyst is a catalyst that promotes a chemical reaction between a polyol compound and a polyisocyanate compound described later, and can increase the curing speed when forming a polyurethane foam. As a result, dripping is unlikely to occur, and poor appearance of the polyurethane foam can be prevented, as well as staining around the application site.

The catalyst preferably contains a trimerization catalyst from the viewpoint of increasing the curing rate when the polyol composition and the polyisocyanate composition are mixed. The trimerization catalyst is a catalyst that reacts isocyanate groups contained in a polyisocyanate compound to trimerize them and promote the formation of an isocyanurate ring. As the trimerization catalyst, nitrogen-containing aromatic compounds such as tris(dimethylaminomethyl)phenol, 2,4-bis(dimethylaminomethyl)phenol, and 2,4,6-tris(dialkylaminoalkyl)hexahydro-S-triazine, carboxylic acid alkali metal salts such as potassium acetate, potassium 2-ethylhexanoate, and potassium octylate, tertiary ammonium salts such as trimethylammonium salt, triethylammonium salt, and triphenylammonium salt, and quaternary ammonium salts such as tetramethylammonium salt, tetraethylammonium, tetraphenylammonium salt, and triethylmonomethylammonium salt can be used. As the ammonium salt, ammonium salts of carboxylic acids such as 2,2-dimethylpropanoic acid can be mentioned, and more specifically, quaternary ammonium salts of carboxylic acids can be mentioned. These can be used alone or in combination of two or more kinds.
Among these, one or more selected from alkali metal carboxylates and quaternary ammonium carboxylates are preferred, and among these, quaternary ammonium carboxylates are more preferred.

The amount of the trimerization catalyst is preferably 0.5 to 25 parts by mass, more preferably 1 to 18 parts by mass, and even more preferably 1.5 to 15 parts by mass, per 100 parts by mass of the polyol compound. If the amount of the trimerization catalyst is equal to or greater than these lower limits, trimerization of the polyisocyanate compound is more likely to occur, improving the flame retardancy of the resulting polyurethane foam and increasing the curing speed. On the other hand, if the amount of the trimerization catalyst is equal to or less than the upper limit, the reaction is easier to control.

From the viewpoint of further increasing the curing rate when the polyol composition and the polyisocyanate composition are mixed, the catalyst preferably contains the above-mentioned trimerization catalyst and resinification catalyst.
The resinification catalyst is a catalyst that promotes the reaction between a polyol compound and a polyisocyanate compound. Examples of the resinification catalyst include amine-based catalysts such as imidazole compounds and piperazine compounds, and metal-based catalysts.
Examples of the imidazole compound include tertiary amines in which the secondary amine at the 1-position of the imidazole ring is substituted with an alkyl group, an alkenyl group, or the like. Specific examples include N-methylimidazole, 1,2-dimethylimidazole, 1-ethyl-2-methylimidazole, 1-methyl-2-ethylimidazole, 1,2-diethylimidazole, and 1-isobutyl-2-methylimidazole. In addition, imidazole compounds in which the secondary amine in the imidazole ring is substituted with a cyanoethyl group may also be used.
Furthermore, examples of the piperazine compound include tertiary amines such as N-methyl-N'N'-dimethylaminoethylpiperazine and trimethylaminoethylpiperazine.
In addition to imidazole compounds and piperazine compounds, examples of the resinification catalyst include various tertiary amines such as pentamethyldiethylenetriamine, triethylamine, N-methylmorpholinebis(2-dimethylaminoethyl)ether, N,N,N',N",N"-pentamethyldiethylenetriamine, N,N,N'-trimethylaminoethyl-ethanolamine, bis(2-dimethylaminoethyl)ether, N,N-dimethylcyclohexylamine, diazabicycloundecene, triethylenediamine, tetramethylhexamethylenediamine, and tripropylamine.

Examples of the metal catalyst include metal salts of lead, tin, bismuth, copper, zinc, cobalt, nickel, etc., and preferably organic acid metal salts of lead, tin, bismuth, copper, zinc, cobalt, nickel, etc. More preferred are dibutyltin dilaurate, dioctyltin dilaurate, dioctyltin versatate, bismuth trioctate, bismuth tris(2-ethylhexanoate), tin dioctylate, lead dioctylate, etc., and among these, organic acid bismuth salts are even more preferred.
The resinification catalyst may be used alone or in combination of two or more. Among the above, imidazole compounds, tertiary amines, and organic acid bismuth salts are preferred. Furthermore, it is more preferred to use one or more selected from tertiary amines and organic acid bismuth salts, and an embodiment using both of them is also preferred.

The amount of resinification catalyst is preferably 0.5 to 25 parts by mass, more preferably 1 to 18 parts by mass, and even more preferably 1.5 to 12 parts by mass, per 100 parts by mass of polyol compound. If the amount of resinification catalyst is equal to or greater than these lower limits, urethane bonds are more easily formed and the reaction proceeds quickly. On the other hand, if the amount is equal to or less than these upper limits, the reaction rate is easier to control.

When a trimerization catalyst and a resinification catalyst are used in combination as catalysts, the amount of the resinification catalyst relative to the trimerization catalyst (amount of resinification catalyst/amount of trimerization catalyst) is preferably 0.2 to 10, and more preferably 0.5 to 2.

The total amount of catalyst in the polyol composition is not particularly limited, but is preferably 2 to 40 parts by mass, more preferably 4 to 25 parts by mass, and even more preferably 5 to 20 parts by mass. If it is equal to or greater than these lower limits, the formation of urethane bonds and trimerization will proceed appropriately, making it easier to achieve good flame retardancy and increase the curing rate. If it is equal to or less than these upper limits, it will be easier to control the urethane formation and trimerization reactions.

[Low-boiling point compounds with boiling points below 0°C]
The polyol composition of the present invention contains a low-boiling compound having a boiling point of 0° C. or less. The low-boiling compound discharges the polyol composition by its vapor pressure, and vaporizes when the polyol composition is discharged, thereby foaming the polyol composition and the polyurethane composition described below. In this specification, the boiling point means the boiling point at 1 atmospheric pressure. Here, the boiling point of the low-boiling compound means the boiling point of the low-boiling compound alone, and does not mean, for example, the boiling point of the azeotropic low-boiling compound and another compound when the low-boiling compound forms an azeotropic mixture with the other compound.

If the boiling point of the low-boiling compound exceeds 0°C, it becomes difficult to extrude the polyol composition, especially if it contains a filler. From the viewpoint of making it easier to extrude the polyol composition, the boiling point of the low-boiling compound is preferably -10°C or lower, and more preferably -15°C or lower.

Examples of low-boiling compounds with a boiling point of 0°C or less include hydrofluoroolefins (HFOs) such as 1,3,3,3-tetrafluoropropene (HFO-1234ze), 1,2,3,3,3-pentafluoropropene (HFO-1225ye), 1,1,1,3,3-pentafluoropropene (HFO-1225zc), and 2,3,3,3-tetrafluoropropene (HFO-1234yf); hydrocarbons with 1 to 4 carbon atoms, such as ethane, propane, isobutane, and various butanes such as normal butane; dimethyl ether, nitrogen, carbon dioxide, and compressed air.

A specific example of the above-mentioned hydrocarbons having 1 to 4 carbon atoms is LPG (liquefied petroleum gas) containing propane and butanes as main components.
Among the low-boiling compounds having a boiling point of 0° C. or less, 1,3,3,3-tetrafluoropropene (HFO-1234ze), dimethyl ether, LPG, and nitrogen are preferred. These may be used alone or in combination. For example, it is also preferred to use a combination of dimethyl ether and LPG, and it is also preferred to further combine these with nitrogen.

The content of the low-boiling point compound having a boiling point of 0°C or less in the polyol composition is preferably 5 to 50 parts by mass, more preferably 8 to 35 parts by mass, and even more preferably 10 to 30 parts by mass, per 100 parts by mass of the polyol compound.

The polyol composition contains a low-boiling compound having a boiling point of 0°C or less, but may contain a blowing agent having a boiling point of more than 0°C, as long as the effects of the present invention are not impaired. The amount of the blowing agent having a boiling point of more than 0°C is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 0% by mass, based on the total amount of the polyol composition.

[Filler]
The polyol composition of the present invention may contain a filler. By containing a filler, shrinkage of the obtained polyurethane foam can be suppressed. When the polyol composition contains a filler, the content thereof is preferably 5 to 100 parts by mass, more preferably 10 to 50 parts by mass, based on 100 parts by mass of the polyol compound.

Examples of the filler include a solid flame retardant and an inorganic filler.
The use of a solid flame retardant as a filler can effectively improve the flame retardancy of the polyurethane foam. The solid flame retardant is usually in a state of being dispersed in the polyol composition as a powder component. The solid flame retardant is a flame retardant that is solid at room temperature (23° C.) and normal pressure (1 atm).
Specific examples of solid flame retardants include red phosphorus-based flame retardants, phosphate-containing flame retardants, bromine-containing flame retardants, chlorine-containing flame retardants, antimony-containing flame retardants, boron-containing flame retardants, and metal hydroxides. These may be used alone or in combination of two or more.

<Red phosphorus-based flame retardants>
The red phosphorus-based flame retardant may be made of red phosphorus alone, may be red phosphorus coated with a resin, a metal hydroxide, a metal oxide, or may be red phosphorus mixed with a resin, a metal hydroxide, a metal oxide, or the like. The resin that coats the red phosphorus or mixes with the red phosphorus is not particularly limited, but examples thereof include thermosetting resins such as phenol resin, epoxy resin, unsaturated polyester resin, melamine resin, urea resin, aniline resin, and silicone resin. From the viewpoint of flame retardancy, metal hydroxides are preferred as the compound to be coated or mixed. The metal hydroxide to be used may be appropriately selected from those described below.

<Phosphate-containing flame retardants>
Examples of the phosphate-containing flame retardant include phosphates formed from salts of various phosphoric acids and at least one metal or compound selected from the group consisting of metals in Groups IA to IVB of the periodic table, ammonia, aliphatic amines, aromatic amines, and heterocyclic compounds containing nitrogen in the ring.
The phosphoric acid is not particularly limited, but examples thereof include monophosphoric acid, pyrophosphoric acid, and polyphosphoric acid.
Examples of metals in Groups IA to IVB of the periodic table include lithium, sodium, calcium, barium, iron (II), iron (III), and aluminum.
Examples of the aliphatic amine include methylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, piperazine, etc. Examples of the aromatic amine include aniline, o-triidine, 2,4,6-trimethylaniline, anisidine, 3-(trifluoromethyl)aniline, etc. Examples of the heterocyclic compound containing nitrogen in the ring include pyridine, triazine, melamine, etc.

Specific examples of the phosphate-containing flame retardant include monophosphate, pyrophosphate, polyphosphate, etc. Here, the polyphosphate is not particularly limited, but examples thereof include ammonium polyphosphate, piperazine polyphosphate, melamine polyphosphate, ammonium amide polyphosphate, aluminum polyphosphate, etc.
The phosphate-containing flame retardant may be used alone or in combination of two or more of the above-mentioned compounds.

<Bromine-containing flame retardants>
The bromine-containing flame retardant is not particularly limited as long as it contains bromine in its molecular structure and is a solid at room temperature and pressure. Examples of the bromine-containing flame retardant include brominated aromatic ring-containing aromatic compounds.
Examples of the brominated aromatic ring-containing aromatic compound include monomeric organic bromine compounds such as hexabromobenzene, pentabromotoluene, hexabromobiphenyl, decabromobiphenyl, decabromodiphenyl ether, octabromodiphenyl ether, hexabromodiphenyl ether, bis(pentabromophenoxy)ethane, ethylene bis(pentabromophenyl), ethylene bis(tetrabromophthalimide), and tetrabromobisphenol A.

The brominated aromatic ring-containing aromatic compound may be a bromine compound polymer.Specific examples of the brominated aromatic ring-containing aromatic compound include polycarbonate oligomers produced from brominated bisphenol A as a raw material, brominated polycarbonates such as copolymers of the polycarbonate oligomers and bisphenol A, and diepoxy compounds produced by the reaction of brominated bisphenol A and epichlorohydrin.Further examples include brominated epoxy compounds such as monoepoxy compounds obtained by the reaction of brominated phenols with epichlorohydrin, poly(brominated benzyl acrylate), brominated phenol condensates of brominated polyphenylene ether, brominated bisphenol A, and cyanuric chloride, brominated (polystyrene), poly(brominated styrene), brominated polystyrenes such as crosslinked brominated polystyrene, crosslinked or non-crosslinked brominated poly(-methylstyrene), and the like.
In addition, compounds other than brominated aromatic ring-containing aromatic compounds such as hexabromocyclododecane may be used.
These bromine-containing flame retardants may be used alone or in combination of two or more.
Among the above, brominated aromatic ring-containing aromatic compounds are preferred, and among these, monomeric organic bromine compounds such as ethylenebis(pentabromophenyl) are preferred.

Chlorine-containing flame retardants include those commonly used in flame-retardant resin compositions, such as polychlorinated naphthalene, chlorendic acid, and dodecachlorododecahydrodimethanodibenzocyclooctene, sold under the trade name "Dechlorane Plus."

<Antimony-containing flame retardants>
Examples of antimony-containing flame retardants include antimony oxide, antimony salts, pyroantimony salts, etc. Examples of antimony oxide include antimony trioxide and antimony pentoxide, etc. Examples of antimony salts include sodium antimonate and potassium antimonate, etc. Examples of pyroantimonate salts include sodium pyroantimonate and potassium pyroantimonate, etc.
The antimony-containing flame retardants may be used alone or in combination of two or more.
The antimony-containing flame retardant used in the present invention is preferably antimony oxide.

<Boron-containing flame retardants>
The boron-containing flame retardant used in the present invention includes borax, boron oxide, boric acid, borate, etc. Examples of boron oxide include diboron trioxide, boron trioxide, diboron dioxide, tetraboron trioxide, and tetraboron pentoxide.
Examples of borates include borates of alkali metals, alkaline earth metals, elements of Groups 4, 12, and 13 of the periodic table, and ammonium. Specific examples include alkali metal borates such as lithium borate, sodium borate, potassium borate, and cesium borate, alkaline earth metal borates such as magnesium borate, calcium borate, and barium borate, zirconium borate, zinc borate, aluminum borate, and ammonium borate.
The boron-containing flame retardants may be used alone or in combination of two or more.
The boron-containing flame retardant used in the present invention is preferably a borate, more preferably zinc borate.

<Metal hydroxide>
Examples of the metal hydroxide used in the present invention include magnesium hydroxide, calcium hydroxide, aluminum hydroxide, iron hydroxide, nickel hydroxide, zirconium hydroxide, titanium hydroxide, zinc hydroxide, copper hydroxide, vanadium hydroxide, tin hydroxide, etc. The metal hydroxide may be used alone or in combination of two or more kinds.

The content of the solid flame retardant in the polyol composition may be appropriately adjusted so that the filler ratio falls within the above range, but is preferably 5 to 100 parts by mass, more preferably 10 to 50 parts by mass, relative to 100 parts by mass of the polyol compound.
When the content of the solid flame retardant is equal to or more than the lower limit, the shrinkage rate of the obtained polyurethane foam can be reduced and the flame retardancy can be improved. When the content of the solid flame retardant is equal to or less than the upper limit, the dischargeability of the polyol composition can be improved.

<Inorganic filler>
Examples of inorganic fillers include silica, diatomaceous earth, alumina, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, ferrites, basic magnesium carbonate, calcium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, dawsonite, hydrotalcite, calcium sulfate, barium sulfate, gypsum fiber, calcium silicate, talc, clay, mica, wollastonite, montmorillonite, bentonite, activated clay, sepiolite, imogolite, sericite, glass fiber, glass beads, silica palan, aluminum nitride, boron nitride, silicon nitride, carbon black, graphite, carbon fiber, carbon palan, charcoal powder, various metal powders, potassium titanate, magnesium sulfate, lead zirconate titanate, aluminum borate, molybdenum sulfide, silicon carbide, stainless steel fiber, various magnetic powders, slag fiber, fly ash, silica alumina fiber, alumina fiber, silica fiber, and zirconia fiber. These inorganic fillers may be used alone or in combination of two or more.
The content of the inorganic filler in the polyol composition may be appropriately adjusted so that the filler ratio falls within the above range, but is preferably 5 to 150 parts by mass, and more preferably 10 to 100 parts by mass, relative to 100 parts by mass of the polyol compound.
When the content of the inorganic filler is equal to or more than the above lower limit, the shrinkage rate of the obtained polyurethane foam can be reduced.When the content of the inorganic filler is equal to or less than the above upper limit, the dischargeability of the polyol composition is improved.

[Liquid flame retardant]
The polyol composition of the present invention may contain a liquid flame retardant. The liquid flame retardant is a flame retardant that is liquid at room temperature and normal pressure. A specific example of the liquid flame retardant is a phosphoric acid ester. By including the liquid flame retardant in the polyol composition, it is possible to improve the flame retardancy without substantially decreasing the discharge flow rate, the mixing property, and the like.

As the phosphate ester, monophosphate ester, condensed phosphate ester, etc. can be used. A monophosphate ester is a phosphate ester having one phosphorus atom in the molecule. There is no limitation on the monophosphate ester as long as it is liquid at room temperature and normal pressure, but examples of the monophosphate ester include trialkyl phosphates such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, and tri(2-ethylhexyl)phosphate, halogen-containing phosphate esters such as tris(β-chloropropyl)phosphate, trialkoxy phosphates such as tributoxyethyl phosphate, aromatic ring-containing phosphate esters such as tricresyl phosphate, trixylenyl phosphate, tris(isopropylphenyl)phosphate, cresyl diphenyl phosphate, and diphenyl(2-ethylhexyl)phosphate, and acidic phosphate esters such as monoisodecyl phosphate and diisodecyl phosphate.

Examples of the condensed phosphate ester include aromatic condensed phosphate esters such as trialkyl polyphosphate, resorcinol polyphenyl phosphate, bisphenol A polycresyl phosphate, and bisphenol A polyphenyl phosphate.
Commercially available condensed phosphate esters include, for example, "CR-733S", "CR-741", and "CR747" manufactured by Daihachi Chemical Industry Co., Ltd., and "ADEKA STAB PFR" and "FP-600" manufactured by ADEKA Corporation.

The liquid flame retardants may be used alone or in combination of two or more of the above. Among these, monophosphate esters are preferred from the viewpoint of making it easier to adjust the viscosity of the polyol compound to an appropriate level and from the viewpoint of improving the flame retardancy of the polyurethane foam, and halogen-containing phosphate esters such as tris(β-chloropropyl)phosphate are more preferred.

When the polyol composition contains a liquid flame retardant, the amount of the liquid flame retardant is preferably 5 to 70 parts by mass, more preferably 10 to 60 parts by mass, and even more preferably 20 to 50 parts by mass, per 100 parts by mass of the polyol compound. By making the amount of the liquid flame retardant equal to or greater than these lower limits, the effect of including the liquid flame retardant is easily achieved. Furthermore, by making the amount equal to or less than the upper limits, the foaming of the polyurethane foam is not inhibited by the liquid flame retardant.

[Foam stabilizer]
The polyol composition of the present invention may contain a foam stabilizer. The foam stabilizer improves the foamability of the polyurethane composition obtained from the polyol composition and the polyisocyanate composition.
Examples of the foam stabilizer include surfactants such as polyoxyalkylene-based foam stabilizers such as polyoxyalkylene alkyl ethers, and silicone-based foam stabilizers such as organopolysiloxanes. These foam stabilizers may be used alone or in combination of two or more.
The amount of the foam stabilizer is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, and even more preferably 1 to 5 parts by mass, based on 100 parts by mass of the polyol compound. When the amount of the foam stabilizer is equal to or greater than these lower limits, the polyurethane composition is easily foamed, and a homogeneous polyurethane foam is easily obtained. When the amount of the foam stabilizer is equal to or less than these upper limits, a good balance between the production cost and the obtained effect is obtained.

[water]
The polyol composition of the present invention may contain water. By containing water, the foamability when forming a polyurethane foam is improved. The blend amount of water is, for example, 0.1 to 10 parts by mass, preferably 0.2 to 5 parts by mass, and more preferably 0.3 to 3 parts by mass, based on 100 parts by mass of the polyol compound. By setting the blend amount of water within these ranges, the polyurethane composition can be easily foamed appropriately.

[Other ingredients]
The polyol composition may contain, as necessary, additives such as phenol-based, amine-based, sulfur-based and other antioxidants, anti-settling agents, heat stabilizers, metal damage inhibitors, antistatic agents, stabilizers, crosslinking agents, lubricants, softeners, pigments, and tackifying resins, as well as tackifiers such as polybutene and petroleum resins, provided that the object of the present invention is not impaired.

[Shape retention rate of polyol composition]
The polyol composition of the present invention has excellent shape retention, and the shape retention is preferably 40% or more, more preferably 60% or more. The shape retention of the polyol composition can be calculated by the following formula (1).
(Calculation of shape retention rate)
The polyol composition is poured into a container and the container is kept at 35° C., and then the polyol composition is discharged from the container into a plastic container having an inner diameter of 53 mm and a height of 72 mm so that the volume of the discharged liquid becomes equal to the volume of the plastic container. After 10 seconds have passed, the liquid level is measured and the shape retention rate is calculated based on the following formula (1).
Formula (1) Shape retention rate (%) = (liquid level after 10 seconds) ÷ (initial liquid level) × 100
The container for sealing the polyol composition may be a container described later, and is preferably an aerosol container (spray can). When the polyol composition is discharged, each component constituting the polyol composition is discharged in a uniformly mixed state.
The plastic container is made of polyethylene and has a cylindrical shape. The volume of the discharged liquid is adjusted to be equal to the volume of the plastic container, so the "initial liquid level" in the above formula (1) is 72 mm. In addition, when the liquid level varies depending on the location, the maximum liquid level is measured and this value is regarded as the liquid level after 10 seconds.

[container]
The container of the present invention is a container in which the above-mentioned polyol composition is enclosed. The container is not particularly limited as long as it can discharge the polyol composition by the vapor pressure of the low boiling point compound, and is preferably an aerosol container. The aerosol container, for example, comprises a container body filled with the polyol composition and a cap part that seals the upper part of the container body, and when a button or the like provided on the cap part is pressed, a valve or the like is opened to release the internal pressure, and the polyol composition is discharged from the discharge port provided on the cap part by the vapor pressure of the low boiling point compound.
The method of sealing the polyol composition in the container is not particularly limited, but the components other than the low-boiling compound are mixed as necessary using a disperser or the like, then filled into the container, the container is sealed, and then the low-boiling compound is filled in. The filling of the low-boiling compound can be performed, for example, by opening a valve provided on the cap of the container and injecting the low-boiling compound into the container.

When the polyol composition is discharged from the container, each component constituting the polyol composition is discharged in a state in which it is uniformly mixed. In order to uniformly mix each component constituting the polyol composition, it is recommended to shake the container thoroughly before discharging. The container can be shaken, for example, by holding the container by hand and shaking it up and down. The method of uniformly mixing the polyol composition is not limited to the above-mentioned method. In addition, the temperature of the container when discharging is preferably, for example, 10°C or higher and 40°C or lower. If it is 10°C or higher, the liquid temperature is high to a certain extent, so discharging is good, and if it is 40°C or lower, bursting of the container is prevented.

[Polyurethane composition]
The polyurethane composition of the present invention comprises a polyol composition and a polyisocyanate composition containing a polyisocyanate compound. That is, the above-mentioned polyol composition of the present invention is used as a polyol composition for two-component polyurethane, and is mixed with a polyisocyanate composition containing a polyisocyanate compound to be used as a polyurethane composition. The polyol composition and the polyisocyanate composition are preferably mixed in a mass ratio such that the isocyanate index falls within a predetermined range, as described below.
The polyurethane composition obtained by mixing the polyol composition and the polyisocyanate composition reacts with each other and foams due to the low-boiling point compound contained in the polyol composition described above or the low-boiling point compound contained in the polyisocyanate composition described below, thereby becoming a polyurethane foam.

<Polyisocyanate Composition>
The polyisocyanate composition contains a polyisocyanate compound. As the polyisocyanate compound, a known polyisocyanate compound used for forming a polyurethane foam can be used. As the polyisocyanate compound, for example, an aromatic polyisocyanate, an alicyclic polyisocyanate, an aliphatic polyisocyanate, etc. can be mentioned.
Examples of aromatic polyisocyanates include phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, dimethyldiphenylmethane diisocyanate, triphenylmethane triisocyanate, naphthalene diisocyanate, and polymethylene polyphenyl polyisocyanate (polymeric MDI).

Examples of the alicyclic polyisocyanate include cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and dimethyldicyclohexylmethane diisocyanate.
Examples of the aliphatic polyisocyanate include methylene diisocyanate, ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate, and hexamethylene diisocyanate.

Among these, from the viewpoints of ease of use and availability, aromatic polyisocyanates are preferred, and diphenylmethane diisocyanate, polymeric MDI, or a mixture thereof is more preferred. The polyisocyanates may be used alone or in combination of two or more types.

The polyisocyanate composition usually further contains a low-boiling compound. As the low-boiling compound, the above-mentioned low-boiling compounds having a boiling point of 0° C. or less can be used without any particular limitation. The low-boiling compound used in the polyisocyanate composition may be the same as or different from the low-boiling compound used in the polyol composition.
The proportion of the low boiling point compound contained in the polyisocyanate composition is preferably 5% by mass or more and less than 20% by mass, more preferably 7% by mass or more and less than 15% by mass. By containing 5% by mass or more of the low boiling point compound, sufficient ejection force can be obtained. In addition, by containing less than 20% by mass, the foaming density obtained is not too low, and appropriate physical properties can be obtained.
Furthermore, the polyisocyanate composition may appropriately contain known additives that are blended in polyisocyanates.

<Isocyanate Index>
The isocyanate index of the polyurethane composition of the present invention is preferably 200 or more. When the isocyanate index is 200 or more, the amount of the polyisocyanate compound relative to the polyol compound becomes excessive, which makes it easier for isocyanurate bonds to be formed by the trimer of the polyisocyanate, and as a result, the flame retardancy of the polyurethane foam is improved. In order to further improve the flame retardancy, the isocyanate index is more preferably 250 or more, and even more preferably 340 or more.
The isocyanate index is preferably not more than 1000, more preferably not more than 650, and even more preferably not more than 500. When the isocyanate index is not more than these upper limit values, the resulting polyurethane foam has a good balance between flame retardancy and production costs.

The isocyanate index can be calculated by the following method.
Isocyanate index = equivalents of polyisocyanate ÷ (equivalents of polyol + equivalents of water) × 100
Here, each equivalent number can be calculated as follows:
Equivalent number of polyisocyanate = Amount of polyisocyanate used (g) × NCO content (mass%) / Molecular weight of NCO (mol) × 100
Equivalent number of polyol = OHV x amount of polyol used (g) ÷ molecular weight of KOH (mmol)
OHV is the hydroxyl value of the polyol (mg KOH/g).
Number of water equivalents = amount of water used (g) / molecular weight of water (mol) × number of OH groups in water In each of the above formulas, the molecular weight of NCO is 42 (mol), the molecular weight of KOH is 56,100 (mmole), the molecular weight of water is 18 (mol), and the number of OH groups in water is 2.

[Mixed system]
The present invention also provides a mixing system for mixing a polyol composition and a polyisocyanate composition. As shown in Fig. 1, the mixing system 10 includes a first container 11 in which a polyol composition is enclosed, and a second container 12 in which a polyisocyanate composition is enclosed. Both of the first containers 11 and 12 are aerosol containers (spray cans).
The polyol composition sealed in the first container 11 is discharged by the vapor pressure of the low boiling point compound contained in the polyol composition. The polyisocyanate composition sealed in the second container 12 is discharged by the vapor pressure of the low boiling point compound contained in the polyisocyanate composition. Note that, inside the first container 11, a part of the low boiling point compound vaporizes to form a gas phase. The same is true inside the second container 12.
The polyol composition and the polyisocyanate composition discharged from the first and second containers 11, 12 are mixed while being foamed by a low-boiling point compound or the like, and the polyisocyanate compound reacts with the polyol compound to form a polyurethane foam.

The mixing system 10 may include a mixer 13. The outlets 11A and 12A of the first and second containers 11 and 12 are connected to the mixer 13 via supply lines 11B and 12B. The polyol composition and polyisocyanate composition discharged from the first and second containers 11 and 12 are supplied to the mixer 13 via supply lines 11B and 12B, respectively, and are mixed in the mixer 13. The polyol composition and polyisocyanate composition mixed in the mixer 13 may be sprayed onto the surface to be applied using a sprayer or the like.

The mixer 13 is preferably a static mixer, so-called a static mixer. A static mixer is a mixer without a driving part, and the fluids are mixed by passing through the inside of the tube. An example of the static mixer is one in which a mixer element 13B is arranged inside a tube 13A as shown in FIG. 1. The mixer element 13B may be one formed in a spiral shape or one formed with a plurality of baffles.
The static mixer may also function as an injector, in which case the mixture of the polyol composition and the polyisocyanate composition mixed inside the pipe 13A may be injected from the tip 13C of the pipe as shown in Fig. 1. Note that Fig. 1 shows an embodiment in which the polyol composition and the polyisocyanate composition discharged from the first and second containers 11 and 12 are introduced into the mixer, but a discharge gun, jig, or the like may be provided before the composition is introduced into the mixer.

As an example of an embodiment equipped with a discharge gun before being introduced into the mixer, a mixing system 20 is shown in FIG. 2. The mixing system 20 includes a first container 11, a second container 12, supply lines 11B and 12B, a discharge gun 14, and a mixer 13. The first container 11 and the second container 12 are as described above, and contain a polyol composition and a polyisocyanate composition, respectively. The polyol composition and the polyisocyanate composition are delivered from the first and second containers to the discharge gun 14 via supply lines 11B and 12B, respectively. The discharge gun 14 includes a lever 14A and has an ON-OFF mechanism for delivery. Specifically, when the lever 14A is pulled, the polyol composition and the polyisocyanate composition are delivered to the mixer 13, and when the lever 14A is released, delivery to the mixer 13 is stopped. By using a mixing system 20 equipped with a discharge gun 14, liquid can be delivered as needed, improving workability when forming polyurethane foam.

The polyurethane foam of the present invention is formed from the polyurethane composition described above. In the present invention, the polyurethane foam formed from the polyurethane composition can be used for various purposes, but is preferably used as a heat insulating material. The polyurethane foam has a large number of cells, which provides a heat insulating effect.
The polyurethane foam is particularly preferably used as a thermal insulation material for vehicles or buildings, such as railroad cars, automobiles, ships, and aircraft.
In addition, in the present invention, a polyurethane foam can be formed with a simple structure using a container such as an aerosol container. In addition, since the foam can be formed using a container, it is particularly suitable for cases where the surface to be treated is relatively small. Therefore, it is preferable to use it for repair purposes, for example, by spraying it onto a portion of an existing heat-resistant material that has deteriorated or been damaged. Of course, it is not limited to such uses, and it may also be used to form a new heat-resistant material.

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these.

The evaluation method is as follows:

[Shape retention]
The shape retention rate was calculated and the shape retention was evaluated by the following method.
The polyol composition was filled into an aerosol container, and the container was kept at 35° C., after which the polyol composition was discharged from the container into a plastic container having an inner diameter of 53 mm and a height of 72 mm so that the volume of the discharged liquid was equal to the volume of the plastic container. After 10 seconds had elapsed, the liquid level was measured, and the shape retention rate was calculated based on the following formula (1), and the shape retention was evaluated according to the following criteria.
Formula (1) Shape retention rate (%) = (liquid level after 10 seconds) ÷ (initial liquid level) × 100
A: Shape retention rate of 60% or more B: Shape retention rate of 40% or more but less than 60% C: Shape retention rate of less than 40%

[Curing time]
For the mixtures (polyurethane compositions in which a polyol composition and a polyisocyanate composition are mixed) formed as described in each of the Examples and Comparative Examples, the curing time was determined as the time from the start of discharge until the surface of the mixture was completely dry (until it became sticky), and was evaluated according to the following criteria.
A: Curing time is less than 30 seconds. B: Curing time is between 30 and 60 seconds. C: Curing time is 60 seconds or more.

The components used in the examples and comparative examples are as follows. Note that the number of parts of each component shown in Table 1 indicates the number of parts of the diluted product.

Polyol compounds Aromatic ring-containing polyol compound 1: phthalic acid polyester polyol (manufactured by Hitachi Chemical Co., Ltd., product name: SV-208, aromatic ring concentration 16%, hydroxyl value = 235 mg KOH/g)
Aromatic ring-containing polyol compound 2: phthalic acid polyester polyol (manufactured by Kawasaki Chemical Industries, Ltd., product name: Maximol RLK-087, aromatic ring concentration 8%, hydroxyl value = 200 mg KOH/g)
Aromatic ring-containing polyol compound 3: phthalic acid polyester polyol (manufactured by Kawasaki Chemical Industries, Ltd., product name: Maximol RLK-505, aromatic ring concentration 22%, hydroxyl value = 250 mg KOH/g)
Polyol compound not containing an aromatic ring: Polyether polyol (Sanyo Chemical Industries, Ltd., Sanix GP-1000, hydroxyl value = 168 mg KOH/g)

Resinification catalyst 1: Tertiary amine (active ingredient amount 100 mass%, manufactured by Tosoh Corporation, product name: TOYOCAT TT)
Resinification catalyst 2: bismuth carboxylate (active ingredient amount 80 to 90 mass%, diluted with 2-ethylhexanoic acid, manufactured by Nitto Kasei Co., Ltd., product name: BI-28)
Trimerization catalyst 1: quaternary ammonium carboxylate (active ingredient amount 45 to 55 mass%, diluted with ethylene glycol) (Evonik Japan Co., Ltd., product name: DABCO TMR-7)
Trimerization catalyst 2: Potassium carboxylate (active ingredient: approximately 75% by mass, diluted with ethanediol, manufactured by Evonik Japan Co., Ltd., product name: DABCO K-15)

Filler 1: Red phosphorus-based flame retardant (manufactured by Rinkagaku Kogyo Co., Ltd., product name: Nova Excel 140, metal hydroxide coating, red phosphorus content 94% by mass or more)
Filler 2: Zinc borate (manufactured by Hayakawa Shoji Co., Ltd., product name: Firebreak ZB)
Foam stabilizer: Polyoxyalkylene foam stabilizer (manufactured by Toray Dow Corning Co., Ltd., product name SH-193)
Low boiling point compound 1: DME/LPG
A mixture of DME (dimethyl ether) and LPG. The mixing ratio (mass ratio) is DME/LPG = 6/4 (Iwatani Gas "LPG-D") The boiling point is below 0°C. The boiling point of DME is -24°C.
Boiling point of propane that makes up LPG: -42°C
Boiling point of isobutane, which is a component of LPG: -11.7°C
Boiling point of normal butane that constitutes LPG: -0.5°C
Low boiling point compound 2: HFO
HFO-1234ze (Honeywell, product name: Soltis GBA)
The boiling point of HFO-1234ze is -19°C.
Low boiling point compound 3: Nitrogen
Boiling point: -195.8℃

Polyisocyanate compound: 4,4'-diphenylmethane diisocyanate (4,4'-MDI) (manufactured by Manka Chemical Japan Co., Ltd., product name: PM200)

Example 1
According to the formulation in Table 1, the components other than the low boiling point compound were weighed into a 1000 ml polypropylene beaker, mixed for 5 minutes at 1500 rpm using a disper, transferred to an aerosol container, sealed using a vacuum crimper, and then further filled with the low boiling point compound to obtain a first aerosol container with the polyol composition sealed inside. The amount of the polyol composition filled was 460 g of the polyol composition other than the low boiling point compound, and the low boiling point compound was filled in the blending ratio in Table 1. The shape retention was evaluated using the first aerosol container as described above.
In another aerosol container, 4,4'-diphenylmethane diisocyanate (4,4'-MDI, manufactured by Manka Chemical Japan Co., Ltd., product name: PM200) was charged as a polyisocyanate compound, and then a low boiling point compound (DME/LPG mass ratio 6/4) was further filled to obtain a second aerosol container charged with a polyisocyanate composition. In the polyisocyanate composition, the amount of the low boiling point compound was 65 g relative to 420 g of the polyisocyanate compound.
The polyol composition and the polyisocyanate composition were discharged from the first aerosol container and the second aerosol container, respectively, and mixed in a static mixer. The mixture (polyurethane composition) was sprayed from the tip of the static mixer into a plastic container (a cylindrical container having an inner diameter of 15 cm and a height of 20 cm), and the curing time was measured as described above.

Examples 2 to 11, Comparative Examples 1 to 2
The experiment was carried out in the same manner as in Example 1, except that the composition of the polyol composition was changed as shown in Table 1. The results of the evaluations are shown in Table 1.

It was found that the above-mentioned examples are polyol compositions that satisfy the requirements of the present invention, have excellent shape retention, and have a fast curing time when mixed with a polyisocyanate composition. This shows that polyurethane foams produced using the polyol compositions of the present invention have few appearance defects and are also suppressed from staining around the application site.
In contrast, the polyol composition of Comparative Example 1, which has a low aromatic ring concentration and does not satisfy the requirements of the present invention, had poor shape retention. In addition, the polyol composition of Comparative Example 2, which does not satisfy the requirements of the present invention because it does not contain a catalyst, resulted in a slow curing speed. Therefore, it was found that the use of the polyol composition of the Comparative Example easily caused poor appearance of the polyurethane foam and dirt around the application site.

REFERENCE SIGNS LIST 10 Mixing system 11 First container 12 Second container 11A, 12A Discharge port 11B, 12B Supply line 13 Mixer 13A Tube 13B Mixer element 13C Tip 14 Discharge gun 14A Lever 20 Mixing system

Claims (7)

a first aerosol container containing a polyol composition including a polyol compound containing an aromatic ring, a catalyst, and a low-boiling point compound having a boiling point of 0° C. or less;
a second aerosol container containing a polyisocyanate composition containing a polyisocyanate compound and a low-boiling point compound having a boiling point of 0° C. or less;
the aromatic ring-containing polyol compound includes a phthalic acid polyester polyol,
the catalyst comprises a trimerization catalyst and a resinification catalyst, the trimerization catalyst comprises a quaternary ammonium carboxylate;
Mixed systems, except those containing a tertiary amine catalyst containing at least two cyclohexyl rings. The mixing system according to claim 1, further comprising an alkali metal carboxylate as the trimerization catalyst. The mixing system according to claim 1 or 2, wherein the resinification catalyst contains an organic acid metal salt, and the organic acid metal salt is one or more organic acid metal salts selected from the group consisting of lead, tin, bismuth, copper, zinc, cobalt, and nickel. The mixing system according to any one of claims 1 to 3, wherein the low boiling point compound is one or more selected from the group consisting of dimethyl ether, liquefied petroleum gas, and nitrogen. The mixing system according to any one of claims 1 to 4, wherein the polyol composition contains a filler. The mixing system according to any one of claims 1 to 5, wherein the aromatic ring concentration of the polyol compound containing an aromatic ring is 5 to 30 mass %. The mixing system according to any one of claims 1 to 6, wherein the shape retention rate of the polyol composition calculated by the following formula (1) is 40% or more.
(Calculation of shape retention rate)
The polyol composition is filled into an aerosol container and the container is kept at 35° C., and then the polyol composition is discharged from the container into a plastic container having an inner diameter of 53 mm and a height of 72 mm so that the volume of the discharged liquid becomes equal to the volume of the plastic container. After 10 seconds have passed, the liquid level is measured and the shape retention rate is calculated based on the following formula (1).
Formula (1) Shape retention rate (%) = (liquid level after 10 seconds) ÷ (initial liquid level) × 100