JP2022038409A - Polyurethane foam - Google Patents

Abstract

To provide a polyurethane foam that has superior heat insulation performance and resists dimensional deformation.SOLUTION: A polyurethane foam has a plurality of cells. The closed-cell ratio is 80% or more. Each cell has a cell film including, at least partially, holes therein.SELECTED DRAWING: None

Description

The present invention relates to a polyurethane foam.

Utilizing its excellent heat insulating properties, polyurethane foams are practically used for heat insulating and preventing dew condensation on ceilings, roofs, walls and the like of apartment houses such as condominiums, detached houses and commercial buildings.
In the polyurethane foam, the heat insulating property is one of the important physical properties, and various attempts have been made to improve the heat insulating property. For example, Patent Document 1 contains 0.2 to 7.0% by weight of a high boiling point compound that is foamed by carbonic acid gas and consists of one or more kinds selected from cyclic carbonate esters and fatty acid esters, and has a bubble size of 0. The invention relating to a polyurethane foam (polyurethane foam) characterized in that the closed cell ratio of the foam is 90% or more and 1 to 0.5 mm is disclosed. It is known that a polyurethane foam having a closed cell ratio of a certain level or more is excellent in heat insulating performance because the gas in the bubbles is not easily replaced by air.

Japanese Unexamined Patent Publication No. 2000-230066

However, if the closed cell ratio is increased in order to improve the heat insulating performance, the shape of the foam is easily changed due to a change in ambient temperature, and the dimensions of the polyurethane foam are easily deformed at a high temperature such as a fire. Therefore, the polyurethane foam However, there are cases where problems such as deviation from a predetermined position or deterioration of physical properties such as flame retardancy due to the displacement may occur. In addition, there is a problem that dimensional changes such as shrinkage are likely to occur even at room temperature.
There are measures such as increasing the density of the foam to solve this problem, but there are problems in terms of handleability and productivity.
Therefore, it is an object of the present invention to provide a polyurethane foam having excellent heat insulating performance, being relatively lightweight, and having difficulty in dimensional deformation.

As a result of diligent studies, the present inventor has found that the above-mentioned problems can be solved by a polyurethane foam having a closed cell ratio of a certain level or more and holes formed in at least a part of the cell membrane of the cell, and the present invention has been developed. Completed.
That is, the present invention provides the following [1] to [8].
[1] A polyurethane foam having a plurality of cells, having a closed cell ratio of 80% or more, and having holes formed in at least a part of the cell membrane of the cell.
[2] The polyurethane foam according to the above [1], which is formed from a foamable urethane resin composition containing a polyol compound, a polyisocyanate compound, a flame retardant, a foaming agent, and a catalyst.
[3] The polyurethane foam according to the above [2], wherein the foamable urethane resin composition contains a cell opener containing at least one fine particle component selected from organic fine particles and inorganic fine particles.
[4] The polyurethane foam according to the above [2] or [3], wherein the foaming agent contains a hydrofluoroolefin.
[5] According to the test method of ISO-5660, the total calorific value when heated for 5 minutes at a radiant heat intensity of 50 kW / m ² is 8 MJ / m ² or less, the above [1] to [4]. The polyurethane foam according to any one of.
[6] According to the test method of ISO-5660, the maximum heat generation rate when heated for 5 minutes at a radiant heat intensity of 50 kW / m ² is 200 kW / m ² or less, as described above [1] to [5]. The polyurethane foam according to any one of.
[7] The polyurethane foam according to any one of the above [1] to [6], wherein the subduction distance of the steel ball in the following thermal steel ball evaluation is 10 mm or less.
(Evaluation of hot steel balls)
(1) A polyurethane foam is cut into a cube having a side of 50 mm and used as a test piece.
(2) A steel ball having a diameter of 10.0 mm and a weight of 4.15 g is placed inside an electric furnace set at 800 ° C. and heated for 10 minutes or more.
(3) In an atmosphere of 23 ° C., the steel ball heated in (2) above is immediately placed on the center of the upper part of the test piece of (1) above, and is left to stand until the subduction of the steel ball is completed. Then, the cross section of the sufficiently cooled test piece is cut to measure the subduction distance and the melt diameter distance of the steel ball.
[8] The polyurethane foam according to any one of the above [1] to [7], which is formed by spraying a foamable urethane resin composition containing a polyol compound, a polyisocyanate compound, a flame retardant, a foaming agent, and a catalyst. body.

According to the present invention, it is possible to provide a polyurethane foam having excellent heat insulating properties, being relatively lightweight, and having difficulty in dimensional deformation.

It is a scanning electron micrograph of the polyurethane foam of the present invention in which a hole is formed in a part of a cell membrane. It is a scanning electron micrograph of a polyurethane foam having no pores formed in a cell membrane.

[Polyurethane foam]
The polyurethane foam of the present invention is a polyurethane foam having a plurality of cells, having a closed cell ratio of 80% or more, and having holes formed in at least a part of the cell membrane of the cell.

(Closed cell ratio)
The polyurethane foam of the present invention has a closed cell ratio of 80% or more. When the closed cell ratio of the polyurethane foam is less than 80%, the thermal conductivity is high and the heat insulating property is lowered. The closed cell ratio of the polyurethane foam is preferably 85% or more, more preferably 90% or more, from the viewpoint of improving the heat insulating property. The closed cell ratio means the ratio of closed cells to total bubbles.
The closed cell ratio can be adjusted by adjusting the composition of the effervescent urethane resin composition described later. For example, the type and amount of the defoaming agent described later, the cell opener which is a fine particle solid, the molecular weight and the number of functional groups of the polyol, and different polyols. It can be adjusted according to the combination of the above, the type and amount of the catalyst, and the like.

The closed cell ratio of the polyurethane foam is measured by the dry density measurement by the constant volume expansion method, the open cell ratio is obtained by the following formula (1), and the open cell ratio is based on the formula (2). It is calculated.
Open cell ratio (%) = {(true density [g / cm ³ ])-(apparent density [g / cm ³ ])} / (true density [g / cm ³ ]) × 100 (1)
Closed cell ratio (%) = 100-Open cell ratio obtained from Eq. (1) ... (2)
For dry density measurement, refer to the Shimadzu Corporation website (https://www.an.shimadzu.co.jp/powder/lecture/middle/m04.htm).

(Pore of cell membrane)
The polyurethane foam of the present invention has a plurality of cells, and holes are formed in at least a part of the cell membrane of the cells. The presence of pores in at least a portion of the cell membrane improves the dimensional stability of the polyurethane foam at high and normal temperatures. The pores formed in the cell membrane are confirmed by scanning electron microscopy.
FIG. 1 shows a photograph of the surface of the polyurethane foam of the present invention observed using a scanning electron microscope. In the photograph, a plurality of cells (11a to 11f) are confirmed. Each cell has an internal gas and a cell membrane covering the internal gas, and in FIG. 1, the cell membrane of each cell is observed. The cell membrane is made of polyurethane.
Holes 12a are observed in the cell membrane of the cell 11a, holes 12b are observed in the cell membrane of the cell 11b, and holes 12f are observed in the cell membrane of the cell 11f. For example, when exposed to a high temperature due to heating or the like, if no pores are formed, the internal gas is isolated from the outside of the system by the cell membrane and easily expands and deforms. It is considered that when the pores are formed, the cell and the outside of the system are partially communicated with each other, thereby securing an escape route for gas, which enhances the dimensional stability of the polyurethane foam at high temperature. For the same reason, it is considered that the dimensional stability at room temperature is also improved.
The region observed in black between the cells 11a and 11d is the portion 13 generated during sample preparation, and specifically, the cells are partially formed during sample preparation for observation with a scanning electron microscope. It was created by cutting. Therefore, the site 13 is different from the hole in the present invention. On the other hand, the holes confirmed on the cell membrane are judged to be the holes that were made before the sample was prepared.

Of the cell membranes of the plurality of cells, pores may not be formed in all the cell membranes, and holes may be formed in a part of the cell membrane in the foam. The average pore diameter is not particularly limited, but is preferably 1 to 100 μm, more preferably 2 to 60 μm, and even more preferably 3 to 40 μm. The average pore diameter may be obtained as, for example, the average value of 10 pore diameters among the pores confirmed by the scanning electron microscope. The pore diameter is the maximum distance among any two points on the contour line of the pore observed by the scanning electron microscope.

The number of holes is not particularly limited, but is preferably 1 to 100 per 1 mm ² , and more preferably 2 to 50. When the number of holes is equal to or more than these lower limit values, it becomes easier to suppress the dimensional change of the polyurethane foam at high temperature and normal temperature, and when the number of holes is equal to or less than these upper limit values (or in a state of coalescence and enlargement). If there is, it becomes difficult for the heat insulating property to deteriorate.
The method for forming pores in the cell film of the polyurethane foam is not particularly limited, but for example, a cell containing an increase in internal reaction heat due to catalyst adjustment, a delay in resin curability, a fine particle component (organic fine particles, inorganic fine particles), and the like. The use of openers, combinations of long-chain and short-chain polyols, etc. may be mentioned.

In the polyurethane foam of the present invention, the sinking distance of the steel ball in the following thermal steel ball evaluation is 10 mm or less.
(Evaluation of hot steel balls)
(1) A polyurethane foam is cut into a cube having a side of 50 mm and used as a test piece.
(2) A steel ball having a diameter of 10.0 mm and a weight of 4.15 g is placed inside an electric furnace in which the temperature inside the furnace is set to 800 ° C. and heated for 10 minutes or more.
(3) In an atmosphere of 23 ° C., the steel ball heated in (2) above is immediately placed on the center of the upper part of the test piece of (1) above, and is left to stand until the subduction of the steel ball is completed. Then, the cross section of the sufficiently cooled test piece is cut to measure the subduction distance and the melt diameter distance of the steel ball.
In this thermal steel ball evaluation, a small program electric furnace (MMF-1) having internal dimensions of 120 mm × 150 mm × 100 mm is used as the electric furnace of (2) above, and SUS304 is used as the steel ball. Immediately after heating the steel ball, the steel ball is placed on the test piece. Therefore, the temperature inside the electric furnace (800 ° C.) can be regarded as the temperature of the steel ball when the steel ball is placed on the test piece.

In the above thermal steel ball evaluation, regarding the diameter and weight of the steel ball, the diameter is 10.0 ± 0.2 mm, the weight is 4.15 ± 0.3 g, and the temperature inside the electric furnace is in the range of 795 to 805 ° C. If there is, the same hot steel ball evaluation can be obtained by setting the other conditions as described above. Therefore, the evaluation may be carried out within the range of such diameter, weight, and temperature inside the electric furnace.

By setting the steel ball sinking distance in the evaluation of the hot steel ball of the polyurethane foam of the present invention within the above-mentioned predetermined range, it is possible to prevent the polyurethane foam from burning and spreading when exposed to a fire or the like.

In the polyurethane foam of the present invention, the sinking distance of the steel ball in the evaluation of the hot steel ball is preferably 10 mm or less. When the subduction distance of the steel ball is 10 mm or less, the polyurethane foam does not easily burn and spread when exposed to a fire or the like, and the spread of fire can be effectively prevented. From the viewpoint of effectively preventing the spread of fire, the subduction distance of the steel ball is preferably 5 mm or less, more preferably 3 mm or less, still more preferably 0 mm.

The polyurethane foam of the present invention preferably has a melt diameter distance of 20 mm or less in the evaluation of hot steel balls. When the melt diameter distance is 20 mm or less, the polyurethane foam does not easily spread when exposed to a fire or the like, and the spread of fire can be effectively prevented. From the viewpoint of effectively preventing the spread of fire, the melt diameter distance is preferably 15 mm or less, more preferably 13 mm or less, still more preferably 12 mm or less. The melting diameter distance is 0 mm or more.

The steel ball subduction distance and the melt diameter distance can be adjusted to desired values by adjusting the type of the polyol compound, the isocyanate index, the water content, etc. contained in the foamable urethane resin composition described later. can.

In the hot steel ball evaluation, a cavity is formed in the test piece from the upper surface to the inside by the subduction of the steel ball. The subduction distance of the steel ball means the maximum distance of the cavity in the direction perpendicular to the upper surface of the test piece. The molten diameter distance is the diameter of a hole formed by a heated steel ball on the upper surface of the test piece. The diameter of the hole means the diameter of the circle if the shape of the hole formed on the upper surface of the test piece is circular, and means the major axis if the shape of the hole is elliptical. .. If the shape of the hole is other than circular and elliptical, the maximum distance between any two points of the shape is defined as the diameter of the hole. If the steel ball stays on the surface layer of the test piece and the test piece does not melt and no cavity is formed on the upper surface, the diameter of the carbonized or discolored portion is measured in the same manner as when the cavity is formed. do.

(Total calorific value)
The polyurethane foam of the present invention preferably has a total calorific value of 8 MJ / m ² or less when heated for 5 minutes at a radiant heat intensity of 50 kW / m ² in accordance with the ISO-5660 test method. Since the total calorific value is 8 MJ / m ² or less, the polyurethane foam of the present invention has a predetermined flame retardancy. A polyurethane foam having a predetermined flame retardancy and having a flame retardancy and not spreading by having a steel ball subduction distance and a melt diameter distance of a certain value or less as described above. Therefore, it is possible to more effectively prevent the spread of fire in the event of a fire.
From the viewpoint of further improving the flame retardancy of the polyurethane foam, the total calorific value is preferably 7.8 MJ / m ² or less, more preferably 7.5 MJ / m ² or less, and 7.0 MJ or less. It is more preferably / m ² or less.

(Maximum heat generation rate)
The polyurethane foam of the present invention preferably has a maximum heat generation rate of 200 kW / m ² or less when heated for 5 minutes at a radiant heat intensity of 50 kW / m ² in accordance with the ISO-5660 test method. Since the maximum heat generation rate is 200 kW / m ² or less, the polyurethane foam of the present invention has a predetermined flame retardancy. Further, by adjusting both the maximum heat generation rate and the total heat generation amount as described above, the flame retardancy is further improved.
A polyurethane foam having a predetermined flame retardancy and having a flame retardancy and not spreading by having a steel ball subduction distance and a melt diameter distance of a certain value or less as described above. Therefore, it is possible to more effectively prevent the spread of fire in the event of a fire.
From the viewpoint of further improving the flame retardancy of the polyurethane foam, the maximum heat generation rate is preferably 150 kW / m ² or less, more preferably 130 kW / m ² or less, and 100 kW / m ² or less. Is even more preferable.

The total calorific value and the maximum exothermic rate are obtained by a cone calorimeter test, and can be measured in detail by the method described in Examples.
Since the polyurethane foam of the present invention is not easily dimensionally deformed as described above, it is necessary to prevent the polyurethane foam used in the test from coming into contact with the spark igniter of the cone calorimeter during the cone calorimeter test. Can be done.

The density of the polyurethane foam is not particularly limited, but is preferably in the range of 20 to 200 kg / m ³ . By setting the density to 200 kg / m ³ or less, the polyurethane foam becomes lightweight and the workability on the structure is improved. Further, when the weight is 20 kg / m ³ or more, the desired flame retardancy can be easily developed. From these viewpoints, the density of the polyurethane foam is more preferably in the range of 25 to 100 kg / m ³ , and further preferably in the range of 25 to 80 kg / m ³ . The density of the polyurethane foam can be measured according to JIS K7222.

[Effervescent urethane resin composition]
The polyurethane foam of the present invention is preferably formed from a foamable urethane resin composition containing a polyol compound, a polyisocyanate compound, a flame retardant, a foaming agent, and a catalyst. Specifically, a polyurethane foam can be formed by foaming and curing the foamable urethane resin composition.
Hereinafter, each of these components will be described.

(Polyol compound)
The polyol compound contained in the foamable urethane resin composition of the present invention is not particularly limited, and examples thereof include a polyether polyol, a polyester polyol, and a polymer polyol.
From the viewpoint of improving the flame retardancy of the polyurethane foam, the polyol compound preferably contains a polyester polyol, and more preferably contains a phthalic acid-based polyester polyol. Further, from the viewpoint of improving flame retardancy, it is also preferable to use a halogen-containing polyol or a phosphorus-containing polyol.

As the polyol compound, a long-chain polyol and a short-chain polyol may be used in combination from the viewpoint of dimensional stability of the foam. Here, in the present specification, the long-chain polyol means a polyol having 3 or less functional groups and a hydroxyl value of less than 150 mgKOH / g. Examples of the long-chain polyol include a long-chain polyether polyol and a long-chain polyester polyol. Further, the short-chain polyol means a polyol compound other than the long-chain polyol.
When these are used in combination, the blending amount of the long-chain polyol with respect to 100 parts by mass of the short-chain polyol is preferably 0.5 to 30 parts by mass, and more preferably 1 to 15 parts by mass.

<Polyester polyol>
Examples of the polyester polyol include aromatic polyester polyols and aliphatic polyester polyols, but it is preferable to use aromatic polyester polyols in consideration of the flame retardancy of the obtained polyurethane foam. The aromatic polyester polyol is a condensate of an aromatic dicarboxylic acid such as o-phthalic acid (phthalic acid), m-phthalic acid (isophthalic acid), p-phthalic acid (terephthalic acid), and naphthalenedicarboxylic acid and glycol. Is preferable. Among them, the polyol compound is a condensation of phthalic acid and glycol from the viewpoint of enhancing the flame retardancy of the polyurethane foam, reducing the values of the steel ball sinking distance and the melt diameter distance described above, and improving the performance of not spreading. It is preferable to contain a phthalic acid-based polyester polyol which is a product, and more preferably to contain a p-phthalic acid-based polyester polyol which is a condensate of p-phthalic acid and glycol.
The glycol is not particularly limited, but it is preferable to use known low molecular weight aliphatic glycols as constituents of polyester polyols such as ethylene glycol, propylene glycol and diethylene glycol.

From the viewpoint of reducing the values of the steel ball subduction distance and the melt diameter distance described above and enhancing the performance of not spreading, the content of the phthalic acid-based polyester polyol in the total amount of the polyol compound is preferably 60% by mass or more. It is preferably 70% by mass or more, more preferably 75% by mass or more.

The hydroxyl value of the polyester polyol is preferably 100 to 400 mgKOH / g, more preferably 150 to 350 mgKOH / g. The hydroxyl value is a value measured according to JIS K1557-1: 2007.

<Polyether polyol>
The polyether polyol is a polyoxyalkylene polyol obtained by ring-opening addition polymerization of an alkylene oxide to an initiator having two or more active hydrogen atoms. Specific examples of the initiator include aliphatic polyhydric alcohols (eg, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,6-hexane). Glycols such as diols, neopentyl glycols, cyclohexylene glycols and cyclohexanedimethanol, triols such as trimethylolpropane and glycerin, tetrafunctional alcohols such as pentaerythritol, polyfunctionals such as sucroses and sorbitols), Aliphatic amines (eg, alkylenediamines such as ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, neopentyldiamine, alkanolamines such as monoethanolamine, diethanolamine), aromatic amines (eg, aniline, tolylenediamine, xylyl). (Rhendiamine, diphenylmethanediamine, Mannig condensate, etc.), etc.) can be mentioned, and these may be used alone or in combination of two or more.

As the polyether polyol, from the viewpoint of improving the moldability at the time of injection and the workability at the time of spraying during urethane foaming, self-reaction activity such as tolylene diamine-based polyether polyol and Mannig-based polyether polyol can be expected. From the viewpoint of enhancing flame retardancy, a sucrose-based polyether polyol and a sorbitol-based polyether polyol are preferable in addition to the above-mentioned ones.

The above-mentioned tolylenediamine-based polyether polyol is a polyether polyol obtained by using tolylenediamine as an initiator. The same applies to the sucrose-based polyether polyol and the sorbitol-based polyether polyol.
The Mannich-based polyether polyol is obtained by utilizing the Mannich reaction, and is obtained by adding an alkylene oxide to a Mannich condensate having two or more hydroxyl groups in the molecule, or such a Mannich condensate. It is a polyether polyol. More specifically, at least one of phenol and an alkyl substituted derivative thereof, a Mannich condensation obtained by a Mannich reaction of formaldehyde and alkanolamine, or at least one of ethylene oxide and propylene oxide in this compound is ring-opened addition polymerization. It is a polyether polyol obtained by making it.

The hydroxyl value of the polyether polyol is preferably 200 to 1000 mgKOH / g, more preferably 300 to 600 mgKOH / g.

<Polymer polyol>
Examples of the polymer polyol include those containing a polymer component such as a polyacrylic nitrile or an acrylonitrile-styrene copolymer with respect to a polyester polyol, a polyether polyol, or the like. The polymer components such as polyacrylonitrile (acrylonitrile polymer) and acrylonitrile-styrene copolymer correspond to the organic fine particles described later.

(Cell opener)
The foamable urethane resin composition of the present invention preferably contains a cell opener. The inclusion of the cell opener facilitates the formation of pores in the cell membrane of the foam, promotes the escape of gas at high temperatures, suppresses deformation such as expansion, and improves dimensional stability at room temperature. The cell opener is a material containing at least one fine particle component selected from organic fine particles and inorganic fine particles.
The organic fine particles used as the cell opener include, for example, a polymer of at least one monomer selected from the group consisting of acrylonitrile, metaacrylonitrile, fluorine-containing acrylonitrile, α-ethylacrylonitrile, styrene, vinyl acetate, and acrylic monomers. , Silicone polymer and the like, and examples of the inorganic fine particles include silicon-containing particles such as silica particles.

The cell opener may be composed of only at least one fine particle component selected from organic fine particles and inorganic fine particles, or at least one fine particle component selected from organic fine particles and inorganic fine particles, a surfactant and the like. It may be a mixture with. Further, a cell opener-containing polyol in which a polyol compound and a cell opener are mixed in advance may be used.

The content of the fine particle component in the cell opener is not particularly limited, but is, for example, 3 to 100% by mass, preferably 15 to 100% by mass.
The content of the cell opener in the cell opener-containing polyol is not particularly limited, but is, for example, 0.01 to 10% by mass, preferably 0.05 to 5% by mass.

When a cell opener is used, the content of the cell opener in the foamable urethane resin composition is preferably 0.01 to 50 parts by mass with respect to 100 parts by mass of the polyol compound from the viewpoint of maintaining the closed cell ratio above a certain level. It is more preferably 0.1 to 15 parts by mass.

(Polyisocyanate compound)
As the polyisocyanate compound contained in the foamable urethane resin composition, various polyisocyanate compounds such as aromatic, alicyclic, and aliphatic compounds having two or more isocyanate groups can be used. It is preferable to use liquid diphenylmethane diisocyanate (MDI) because of its ease of handling, quick reaction, excellent physical characteristics of the obtained polyurethane foam, and low cost. Examples of the liquid MDI include crude MDI (also referred to as polypeptide MDI). Specific commercial products of liquid MDI include "44V-10", "44V-20" (manufactured by Sumika Cobestrourethane Co., Ltd.), "Millionate MR-200" (Nippon Polyurethane Industry Co., Ltd.) and the like. Further, MDI containing uretonimine (for example, "Millionate MTL" as a commercially available product: manufactured by Nippon Polyurethane Industry Co., Ltd.) may be used. Further, a compound in which a part of the isocyanate active group in the isopolycyanate compound is reacted with the hydroxyl group-containing compound to enhance the affinity with the polyol in advance may be used. In addition to the liquid MDI, another polyisocyanate compound may be used in combination, and as the polyisocyanate compound to be used in combination, a polyisocyanate compound known in the technical field of polyurethane can be used without limitation.

The range of the isocyanate index of the foamable urethane resin composition of the present invention is preferably 150 to 700, more preferably 200 to 650, and further preferably 250 to 600. When the isocyanate index is in such a range, it becomes easy to adjust the sinking distance and the molten diameter distance of the steel ball in the above-mentioned thermal steel ball evaluation to a desired range.
The isocyanate index (INDEX) is calculated by the following method.

INDEX = equivalent of isocyanate ÷ (equivalent of polyol + equivalent of water) x 100
here,
Equivalent number of isocyanate = number of copies of polyisocyanate used x NCO content (%) x 100 / NCO molecular weight Equivalent number of polyol = OHV x number of copies of polyol ÷ molecular weight of KOH, OHV is the hydroxyl value of the polyol (mgKOH / g),
Equivalent number of water = number of copies of water used x number of OH groups of water / molecular weight of water. In the above formula, the unit of the number of copies used is the weight (g), the molecular weight of the NCO group is 42, and the NCO content is the ratio of the NCO group in the polyisocyanate compound expressed by mass%. For convenience of unit conversion, the molecular weight of KOH is 56100, the molecular weight of water is 18, and the number of OH groups of water is 2.

(Flame retardants)
The foamable urethane resin composition of the present invention preferably contains a flame retardant. Examples of the flame retardant include a solid flame retardant and a liquid flame retardant. By containing the flame retardant, the flame retardancy of the obtained polyurethane foam is improved, and the shape of the polyurethane foam is less likely to be deformed when exposed to heat. In particular, it is preferable to use a phosphoric acid ester-based flame retardant, which will be described later, as the liquid flame retardant.
Here, the solid flame retardant means a flame retardant that is solid at 23 ° C, and the liquid flame retardant means a flame retardant that is liquid at 23 ° C.

(Liquid flame retardant)
The foamable urethane resin composition of the present invention preferably contains a liquid flame retardant at room temperature. By containing the liquid flame retardant, it becomes easy to adjust the above-mentioned steel ball subduction distance and melt diameter distance to a desired range, and by being liquid, the equipment used when using the foamable urethane resin composition, etc. Wear can be suppressed.
Examples of the liquid flame retardant include phosphoric acid ester-based flame retardants such as monophosphate ester and condensed phosphoric acid ester.
The monophosphate ester is not particularly limited, and examples thereof include trimethyl phosphate, triethyl phosphate, tricresyl phosphate, cresyldiphenyl phosphate, and tris (β-chloropropyl) phosphate.
The condensed phosphoric acid ester is not particularly limited, and is, for example, resorcinol polyphenyl phosphate (trade name CR-733S), bisphenol A polycredyl phosphate (trade name CR-741), and aromatic condensed phosphoric acid ester (trade name CR747). ) And so on.

(Solid flame retardant)
Examples of the solid flame retardant include a boron-containing flame retardant, a red phosphorus, a bromine-containing flame retardant, a phosphate-containing flame retardant, an antimony-containing flame retardant, a phosphinic acid-based flame retardant, and a metal hydroxide-based flame retardant. Among them, a boron-containing flame retardant and a bromine-containing flame retardant are preferable, and a boron-containing flame retardant is more preferable. By using the solid flame retardant, in addition to enhancing the flame retardancy, it becomes easy to suppress the shape deformation when the polyurethane foam is exposed to heat.

<Boron-containing flame retardant>
Specific examples of the boron-containing flame retardant include alkali metal borate salts such as lithium borate, sodium borate, potassium borate, and cesium borate, and boric acid such as magnesium borate, calcium borate, and barium borate. Examples thereof include alkaline earth metal salts, zirconium borate, zinc borate, aluminum borate, and ammonium borate. Of these, zinc borate is preferable.

<Brominated flame retardant>
The brominated flame retardant is not particularly limited as long as it is a compound containing bromine in its molecular structure, and examples thereof include aromatic brominated compounds.
Specific examples of the aromatic brominated compound include, for example, hexabromobenzene, pentabromotoluene, hexabromobiphenyl, decabromobiphenyl, hexabromocyclodecane, decabromodiphenyl ether, octabromodiphenyl ether, hexabromodiphenyl ether, and bis. (Pentabromophenoxy) Monomer-based organic bromine compounds such as ethane, ethylenebis (pentabromophenyl), ethylenebis (tetrabromophthalimide), tetrabromobisphenol A, polycarbonate oligomers produced from brominated bisphenol A, the above. Bromine such as brominated polycarbonate such as a copolymer of polycarbonate oligomer and bisphenol A, diepoxy compound produced by reaction between brominated bisphenol A and epichlorohydrin, and bromine such as monoepoxy compound obtained by reaction between brominated phenols and epichlorohydrin. Epoxy compounds, poly (brominated benzyl acrylate), brominated polyphenylene ether, brominated bisphenol A, condensates of cyanur chloride and brominated phenol, brominated (polystyrene), poly (brominated styrene), crosslinked brominated polystyrene, etc. Examples thereof include halogenated bromine compound polymers such as brominated polystyrene, cross-linked or non-cross-linked brominated poly (α-methylstyrene).
Among these, ethylene bis (pentabromophenyl), ethylene bis (tetrabromophthalimide), hexabromobenzene and the like are preferable.

<Phosphate-containing flame retardant>
The phosphate-containing flame retardant is, for example, phosphorus composed of a salt of phosphoric acid and at least one metal or compound selected from the metals of Group IA to IVB of the Periodic Table, ammonia, aliphatic amines, and aromatic amines. Phosphate can be mentioned.
The phosphoric acid is not particularly limited, and examples thereof include various phosphoric acids such as monophosphoric acid, pyrophosphoric acid, and polyphosphoric acid.
Examples of the metals of Group IA to Group 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 and the like. Further, examples of the aromatic amine include pyridine, triazine, melamine and the like.
The above-mentioned phosphate-containing flame retardant may be subjected to a known water resistance improving treatment such as a silane coupling agent treatment or a coating with a melamine resin.

Specific examples of the phosphate-containing flame retardant include monophosphate, pyrophosphate, polyphosphate and the like.
The monophosphate is not particularly limited, but for example, ammonium salts such as ammonium phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, monosodium phosphate, disodium phosphate, trisodium phosphate, and phosphite. Sodium salts such as monosodium, disodium phosphite, sodium hypophosphite, monopotassium phosphate, dipotassium phosphate, tripotassium phosphate, monopotassium phosphite, dipotassium phosphite, hypophosphite Potassium salts such as potassium, monolithium phosphate, dilithium phosphate, trilithium phosphate, monolithium phosphate, dilithium phosphate, lithium salts such as lithium hypophosphite, barium dihydrogen phosphate, phosphorus Barium salts such as barium hydrogen phosphate, tribarium phosphate, barium hypophosphite, magnesium monohydrogen phosphate, magnesium hydrogen phosphate, trimagnesium phosphate, magnesium salts such as magnesium hypophosphite, calcium dihydrogen phosphate , Calcium hydrogen phosphate, tricalcium phosphate, calcium salts such as calcium hypophosphite, zinc salts such as zinc phosphate, zinc phosphite, zinc hypophosphite and the like.

The polyphosphate is not particularly limited, and examples thereof include ammonium polyphosphate, piperazine polyphosphate, melamine polyphosphate, ammonium polyphosphate amide, and aluminum polyphosphate.
Among these, monophosphate is preferably used, and ammonium dihydrogen phosphate is more preferable, because the self-extinguishing property of the phosphate-containing flame retardant is improved.
The phosphate-containing flame retardant may be used alone or in combination of two or more.

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

<Phosphinic acid flame retardant>
Examples of the phosphinic acid-based flame retardant include phosphinic acid, dimethylphosphinic acid, methylethylphosphinic acid, methylpropylphosphinic acid, diethylphosphinic acid, dioctylphosphinic acid, phenylphosphinic acid, diethylphenylphosphinic acid, diphenylphosphinic acid, and bis ( 4-methoxyphenyl) phosphinic acid and the like can be mentioned.

<Metal hydroxide flame retardant>
Examples of the metal hydroxide-based flame retardant include magnesium hydroxide, calcium hydroxide, aluminum hydroxide, iron hydroxide, nickel hydroxide, zirconium hydroxide, titanium hydroxide, zinc hydroxide, copper hydroxide, and hydroxide. Examples include vanadium and tin hydroxide. The metal hydroxide-based flame retardant may be used alone or in combination of two or more.

Examples of the solid flame retardant other than the above-mentioned solid flame retardant include phosphazene, a phosphinic acid metal salt, a silicone-based flame retardant, and an organic sulfonate-based flame retardant.

The content of the flame retardant is preferably 5 to 100 parts by mass, more preferably 10 to 80 parts by mass, and even more preferably 20 to 70 parts by mass with respect to 100 parts by mass of the polyol compound.

(Defoamer)
The flame-retardant urethane resin composition of the present invention may contain a defoaming agent. As the defoaming agent, for example, a compound having a polar portion and a non-polar portion in the molecule and having a surface-active effect can be used. Specific examples of the defoaming agent include silicone defoaming agents such as organopolysiloxane. Further, the silicone foam stabilizer may contain a graft copolymer of polydimethylsiloxane and polyethylene glycol.

(Effervescent agent)
Specific examples of the foaming agent include water, low boiling point hydrocarbons, chlorinated aliphatic hydrocarbon compounds, fluorine compounds, hydrochlorofluorocarbon compounds, hydrofluorocarbons, ether compounds, hydrofluoroolefins and the like. Further, examples of the foaming agent include organic physical foaming agents such as a mixture of these compounds, and inorganic physical foaming agents such as nitrogen gas, oxygen gas, argon gas and carbon dioxide gas.
Examples of the low boiling point hydrocarbon include propane, butane, pentane, hexane, heptane, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane and the like.
Examples of the chlorinated aliphatic hydrocarbon compound include dichloroethane, propyl chloride, isopropyl chloride, butyl chloride, isobutyl chloride, pentyl chloride, isopentyl chloride and the like.
Examples of the fluorine compound include CHF ₃ , CH ₂ F ₂ , CH ₃ F and the like.
Examples of the hydrochlorofluorocarbon compound include trichlormonofluoromethane, trichlorotrifluoroethane, dichloromonofluoroethane (for example, HCFC141b (1,1-dichloro-1-fluoroethane), HCFC22 (chlorodifluoromethane), HCFC142b (). 1-chloro-1,1-difluoroethane)) and the like can be mentioned.
Examples of the hydrofluorocarbon include HFC-245fa (1,1,1,3,3-pentafluoropropane) and HFC-365mfc (1,1,1,3,3-pentafluorobutane).
Examples of the ether compound include diisopropyl ether and the like.
Examples of the hydrofluoroolefin include HFO-1233zd (E) (trans-1-chloro-3,3,3-trifluoropropene) and HFO-1234yf (2,3,3,3-tetrafluoro-1-. Propen) HFO-1224yd (Z) (trans-1-chloro-2,3,3,3,-tetrafluoropropene), HFO-1336mzz (Z) (cis-1,1,1,4,4,4, -Hexafluorobuta-2-ene), HFO-1224yd (Z) and the like can be mentioned.

In the present invention, from the viewpoint of reducing the environmental load, the foaming agent preferably contains a hydrofluoroolefin (HFO), and more preferably contains a hydrofluoroolefin (HFO) and water. As the water, for example, ion-exchanged water, distilled water and the like can be appropriately used. The amount of water with respect to 100 parts by mass of the polyol compound is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, still more preferably 0.1 parts by mass or more, and preferably 2.0 parts by mass. Hereinafter, it is more preferably 1.5 parts by mass or less. When the water content is at least these lower limit values, it becomes easy to foam the foamable urethane resin composition, and it becomes easy to adjust the density to a desired range. Further, when the water content is not more than these upper limit values, it becomes easy to adjust the sinking distance and the melt diameter distance of the steel balls in the evaluation of the hot steel balls of the polyurethane foam to the above-mentioned desired ranges.

In the present invention, the foaming agent preferably contains a hydrofluoroolefin as described above, and more preferably contains both a hydrofluoroolefin and the above-mentioned water. The amount of the hydrofluoroolefin to 100 parts by mass of the polyol compound is preferably 10 to 60 parts by mass, more preferably 15 to 50 parts by mass, still more preferably 25 to 45 parts by mass.

(catalyst)
The foamable urethane resin composition of the present invention preferably contains a catalyst. The catalyst preferably contains a trimerization catalyst, and more preferably contains a urethanization catalyst in addition to the trimerization catalyst. The catalyst contained in the foamable urethane resin composition does not correspond to the inorganic filler in the present invention.

A quantification catalyst is a catalyst that promotes quantification to form an isocyanate bond. The flame retardancy of the polyurethane foam is improved by promoting the triquantization of the polyurethane resin.
Examples of the trimerization catalyst include aromatic compounds such as tris (dimethylaminomethyl) phenol, 2,4-bis (dimethylaminomethyl) phenol, 2,4,6-tris (dialkylaminoalkyl) hexahydro-S-triazine, and acetic acid. Ammonium metal salts such as potassium, sodium acetate, potassium 2-ethylhexanoate, sodium 2-ethylhexanoate, potassium octylate, potassium formate, sodium octylate, aziridines such as 2-ethylaziridin, lead naphthenate, octylic acid Lead compounds such as lead, alcoholate compounds such as sodium methoxydo, phenolate compounds such as potassium phenoxide, tertiary ammonium salts such as trimethylammonium salt, triethylammonium salt, triphenylammonium salt, tetramethylammonium salt, tetraethylammonium, tetraphenyl A quaternary ammonium salt such as an ammonium salt can be used.
The trimerization catalyst may be used alone or in combination of two or more.

The blending amount of the trimerization catalyst is not particularly limited, but is preferably in the range of 0.3 to 15 parts by mass, and more preferably in the range of 0.5 to 10 parts by mass with respect to 100 parts by mass of the urethane resin. It is preferably in the range of 1 to 8 parts by mass, and more preferably in the range of 1 to 8 parts by mass. By setting the amount of the trimerization catalyst within the above range, the isocyanurate bond is appropriately formed and the flame retardancy is improved. In addition, it becomes easy to adjust the closed cell ratio to a desired range.

The urethanization catalyst is a catalyst that promotes the reaction between the polyol component and polyisocyanate. Specific examples thereof include amino compounds, tin compounds, bismuth compounds, and acetylacetone metal salts.
Examples of the amino compound include 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2methylimidazole, and an imidazole compound in which the secondary amine functional group in the imidazole ring is replaced with a cyanoethyl group. , Pentamethyldiethylenetriamine, triethylamine, N-methylmorpholinbis (2-dimethylaminoethyl) ether, bis (2-dimethylaminoethyl) ether, N, N, N', N ", N" -pentamethyldiethylenetriamine, N, N, N'-trimethylaminoethyl-ethanolamine, bis (2-dimethylaminoethyl) ether, N-methyl-N', N'-dimethylaminoethyl piperazine, N, N-dimethylcyclohexylamine, diazabicycloundecene , Triethylenediamine, tetramethylethylenediamine, guanidine derivative, tetramethylhexamethylenediamine, trimethylaminoethylpiperazine, tripropylamine and the like, or acid blocks thereof.
Examples of the tin compound include stannous octylate, dibutyl tin diacetate, and dibutyl tin dilaurate. Examples of the bismuth compound include bismuth neodecanoate and bismuth octylate.
Examples of the acetylacetone metal salt include acetylacetone aluminum, acetylacetone iron, acetylacetone copper, acetylacetone zinc, acetylacetone beryllium, acetylacetone chromium, acetylacetone indium, acetylacetone manganese, acetylacetone molybdenum, acetylacetone titanium, acetylacetone cobalt, acetylacetone vanadium, acetylacetone zirconium and the like. ..
The urethane resin curing catalyst may be used alone or in combination of two or more.

The blending amount of the urethanization catalyst in the foamable urethane resin composition is not particularly limited, but is preferably in the range of 0.5 to 30 parts by mass with respect to 100 parts by mass of the urethane resin, and is preferably 1 to 20 parts by mass. The range is more preferably in the range of 3 to 15 parts by mass. Within the above range, the reaction between the polyol compound and the polyisocyanate compound can be promoted at an appropriate reaction rate. In addition, it becomes easy to adjust the closed cell ratio to a desired range. The urethane resin by 100 parts by mass means a total of 100 parts by mass of the polyol compound and the polyisocyanate compound.

The total amount of all the above catalysts is 0.5 with respect to 100 parts by mass of the urethane resin from the viewpoint of improving the curing rate of urethane (particularly the cell formation by foaming and the expression balance of pores of the present invention) and flame retardancy. It is preferably up to 15 parts by mass, more preferably 1 to 12 parts by mass, still more preferably 2 to 10 parts by mass.

The foamable urethane resin composition can be used as an additive as an additive, for example, an antioxidant such as a phenol-based, amine-based, or sulfur-based agent, a heat stabilizer, a light stabilizer, or a metal damage inhibitor, as long as the effect of the present invention is not impaired. , Antistatic agents, cross-linking agents, lubricants, softeners, pigments, dyes, tackifier resins and the like.

Since the foamable urethane resin composition of the present invention is cured by reacting the polyol compound with the polyisocyanate compound, its viscosity changes with time. Therefore, before using the foamable urethane resin composition, the foamable urethane resin composition is divided into two or more to prevent the foamable urethane resin composition from reacting and curing. When using the foamable urethane resin composition, it is preferable to combine the foamable urethane resin compositions divided into two or more into one.

When the foamable urethane resin composition is divided into two or more, curing does not start by each component of the foamable urethane resin composition divided into two or more, and each component of the foamable urethane resin composition is used. Each component may be divided so that the curing reaction starts after mixing. Usually, the foamable urethane resin composition is divided into a polyol composition containing a polyol compound and a polyisocyanate composition containing a polyisocyanate compound.

The above-mentioned flame retardant, foaming agent, catalyst, and foam stabilizer may be contained in the polyol composition, may be contained in the polyisocyanate composition, and may be contained in the polyol composition and the polyisocyanate composition. May be provided separately, but is preferably contained in the polyol composition.

The foam of the present invention is not particularly limited, but when it is divided into two or more, for example, a two-component foamable urethane resin composition, for example, a polyol prepared by mixing each component in advance. It can be obtained by preparing a composition, a polyisocyanate composition, or the like divided into two or more, mixing them, and foaming them. Mixing and foaming of each component can be performed by a known method. For example, it can be obtained by using a known device such as a high-pressure foaming machine, a low-pressure foaming machine, a spray foaming machine, and a hand mixer. Further, in the case of the one-component type, a method of foaming the foamable urethane resin composition obtained by mixing each component constituting the foamable urethane resin composition by a known method can be mentioned.

(Viscosity of polyol composition)
The viscosity of the polyol composition at 25 ° C. is not particularly limited, but is preferably 2000 mPa · s or less, and preferably 1500 mPa · s or less. By setting the viscosity of the polyol composition to the above upper limit or less, the fluidity of the foamable urethane resin composition is also improved, and poor mixing can be suppressed. The viscosity of the polyol composition can be appropriately adjusted depending on, for example, the molecular weight of the polyol compound used, the type and amount of powder components, and the like. The viscosity of the polyol composition was measured at a temperature of 25 ° C. using a B-type viscometer.

(Use)
The use of the foamable urethane resin composition of the present invention and the polyurethane foam is not particularly limited, but they can be used for filling cavities in structures such as buildings, furniture, automobiles, trains, and ships. .. Further, the foamable urethane resin composition can be used for spraying on the above-mentioned structure. Above all, it is preferable to use it for spraying on a structure, that is, as a foamable urethane resin composition for spraying. A polyurethane foam is formed by spraying the foamable urethane resin composition.
The spraying can be carried out by using a spraying device (for example, GRACO: A-25) and a spray gun (for example, Gasmer: D gun). The spraying can be carried out by adjusting the temperature of the polyol composition and the polyisocyanate composition in separate containers in a spraying device, colliding and mixing the two with the tip of a spray gun, and mistizing the mixed solution by air pressure. Spraying devices and spray guns are known, and commercially available products can be used. In addition, general urethane foam spraying conditions can be applied to the undiluted solution temperature setting, pressure, etc.

The present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

The details of each component used in each Example and Comparative Example are as follows.
(1) Polyol compound (i) Polyester polyol / p-phthalic acid-based polyester polyol (manufactured by Kawasaki Kasei Co., Ltd., product name: RFK-505, hydroxyl value = 250 mgKOH / g, short-chain polyol)
(Ii) Polyether polyol / Mannig-based polyether polyol (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name: DK3776, hydroxyl value = 350 mgKOH / g, short-chain polyol)
-Ethylenediamine-based polyether polyol (manufactured by AGC Inc., product name: Exenol 750ED, hydroxyl value = 760 mgKOH / g, short chain polyol)
-Long-chain polyether polyol (manufactured by Mitsui Chemicals, product name: T-3000, hydroxyl value = 56 mgKOH / g, long-chain polyol)
(Iii) Polymer polyol (polyol containing cell opener)
Acrylonitrile polymer is contained in a Mannich-based polyether polyol in the range of 0.1 to 2 wt% Hydroxyl value = 315 mgKOH / g Short chain polyol

(2) Cell opener, organic fine particles, polymer of acrylonitrile, inorganic fine particles, silica fine particles (fumed silica with a specific surface area of 400 m ² / g or less)

(3) Liquid flame retardant / phosphoric acid ester flame retardant <Tris (β-chloropropyl) phosphate>, (manufactured by Daihachi Chemical Co., Ltd., product name: TMCPP)
(4) Solid flame retardant, red phosphorus (manufactured by Phosphorus Chemical Industry Co., Ltd., product name: Nova Excel 140)
-Brominated flame retardant (manufactured by Manac, product name: HBB-b)
(5) Defoaming agent / silicone-based defoaming agent (manufactured by Toray Dow Corning, product name: SH-193)
(6) Catalyst (i) Quaternary catalyst, quaternary ammonium salt (manufactured by Ebonic Japan, product name: TMR-7), mixture with ethylene glycol (quaternary ammonium salt 45-55% by mass, ethylene glycol 45-55) mass%)
(Ii) Urethane catalyst / imidazole compound, (manufactured by Kao Corporation, product name: KL No. 390), concentration 65-75% by mass
-Bismuth compound, (manufactured by Nitto Kasei Co., Ltd., product name: Neostan U-600), concentration 55-58% by mass
(7) Foaming agent, water, HFO-1233zd <hydrofluoroolefin> (manufactured by Honeywell, product name: Solstice LBA)
(8) Polyisocyanate compound / MDI (manufactured by Sumika Cobestrourethane Co., Ltd., product name: 44V-20)

The methods for measuring each physical property and property are as follows.
[Closed cell ratio]
The polyurethane foam produced in each Example and Comparative Example was cut into 30 mm squares, and the weight was measured to determine the apparent density. The true density was obtained by dry density measurement by the constant volume expansion method, and the open cell ratio was calculated by the following formula (1). A dry automatic density meter (“Accupic II 1340 series” manufactured by Shimadzu Corporation) was used for the measurement. The true density was determined by the gas phase substitution method (pycnometer). The purge pressure was 0.2 MPa.
Open cell ratio (%) = {(true density [g / cm ³ ])-(apparent density [g / cm ³ ])} / (true density [g / cm ³ ]) × 100 (1)
Closed cell ratio (%) = 100-Open cell ratio obtained from the result of equation (1) ... (2)
When the closed cell ratio was 80% or more, it was evaluated as 〇, and when it was less than 80%, it was evaluated as ×.

[Presence / absence of holes]
The polyurethane foam produced in each Example and Comparative Example was cut into a measurable size to prepare a measurement sample.
The surface of the measurement sample was observed with a scanning electron microscope (“N-FE-SEM” manufactured by Hitachi) to observe whether or not pores were formed in the cell membrane of the foam.
The observation magnification was 50 to 300 times, and the measurement was performed under the conditions of an acceleration voltage of 1.0 kV.
FIG. 1 shows the observation results of the scanning electron microscope of Example 2 in which pores were confirmed in the cell membrane as an example. Further, FIG. 2 shows, as an example, the observation results of the scanning electron microscope of Comparative Example 1 in which no pores were confirmed in the cell membrane.

[Evaluation of storage stability]
The polyol compositions prepared in each Example and Comparative Example were transferred to a glass container and stored at 23 ° C. for 24 hours. The polyol composition after 24 hours was visually observed, and those in which separation was confirmed were marked with Δ, and those in which separation could not be confirmed were marked with ◯.

[Evaluation of dimensional stability]
The polyurethane foams obtained in each Example and Comparative Example were cut into a length of 10 cm, a width of 10 cm, and a thickness of 5 cm, and these were stored at room temperature for 7 days. At this time, it was cut so as to include one skin layer inside.
The retention rate of each of the vertical and horizontal lengths was calculated by the following formula, and these were averaged to obtain the shape retention rate and the dimensional stability was evaluated. When the shape retention rate is 100%, it means that the shape is not shrunk at all. It should be noted that each length was measured at the minimum portion. If the evaluation is "○", it means that the foam is hard to shrink and has excellent dimensional stability.
Retention rate = 100 x (length of one side after storage for 7 days) / (length of one side before storage).
〇 ・ ・ Shape retention rate is 90% or more × ・ ・ Shape retention rate is less than 90%

[Evaluation of hot steel balls]
For the polyurethane foams produced in each Example and Comparative Example, the subduction distance and the melt diameter distance of the steel balls were measured by the following procedures (1) to (3).
(1) The polyurethane foam was cut into a cube having a side of 50 mm and used as a test body.
(2) A steel ball (SUS304) having a diameter of 10.0 mm and a weight of 4.15 g was placed inside an electric furnace in which the temperature inside the furnace was set to 800 ° C. and heated for 15 minutes.
(3) In an atmosphere of 23 ° C., the steel ball heated in (2) above was immediately placed on the center of the upper part of the test piece of (1) above, and left to stand until the subduction of the steel ball was completed. Then, the cross section of the test piece sufficiently cooled by leaving it at 23 ° C. for 30 minutes was cut, and the subduction distance and the melt diameter distance of the steel ball were measured.
From the subduction distance and the molten diameter distance of the obtained steel balls, the quality of the property of not spreading was judged as follows.

≪Thermal steel ball evaluation criteria≫
〇 ・ ・ The subduction distance of the steel ball is 5 mm or less and the melt diameter distance is 15 mm or less △ ・ ・ The subduction distance of the steel ball is 5 mm or less and the melt diameter distance is over 15 mm × ・ ・ The above 〇 and Other than △

[Maximum heat generation rate, total heat generation amount]
The maximum heat generation rate and the total heat generation amount of the polyurethane foams produced in each Example and Comparative Example were evaluated by the following cone calorimeter test. A polyurethane foam was produced by spraying on a gypsum board (12.5 mm) using a spraying device and a spray gun. A polyurethane foam adhered using a gypsum board as a base was cut into a length of 10 cm, a width of 10 cm, and a thickness of 3.25 cm (inner gypsum board 12.5 mm) to prepare a sample for a cone calorimeter test. The maximum heat generation rate and the total calorific value when the cone calorimeter test sample was heated at a radiant heat intensity of 50 kW / m ² for 5 minutes according to the test method of ISO-5660 were measured. Similar results were obtained by using a method using a hand mixer in addition to the above method for producing the polyurethane foam.

[Dimensional change at high temperature (evaluation of contact with igniter)]
In the above-mentioned cone calorimeter test, the presence or absence of contact with the igniter was evaluated by heating the polyurethane foam produced in each Example and Comparative Example. The case of no contact (no contact) was evaluated as "○", and the case of contact (with contact) was evaluated as "x". When there is no contact, it is judged that the dimensional stability at high temperature is excellent, and when there is contact, it is judged that the dimensional stability at high temperature is inferior.

[Thermal conductivity]
The foamable urethane resin composition used in each Example and Comparative Example was sprayed onto the structure using a spraying device and a spray gun to prepare a polyurethane foam. Three days after the polyurethane foam was prepared, the foam was cut into a size of 200 mm × 200 mm × 25 mm (including a skin layer inside), and the thermal conductivity was measured. The thermal conductivity of the polyurethane foam in the thickness direction was measured. The device used to measure the thermal conductivity is HC-074 manufactured by Eiko Seiki Co., Ltd.

[Example 1]
A foamable urethane resin composition in which a polyol compound, a cell opener, a liquid flame retardant, a foam stabilizer, a catalyst, and a foaming agent are mixed according to the formulation shown in Table 1 is compliant with JIS A9526 using a spraying device and a spray gun. A polyurethane foam was made by spraying on the structure. Various evaluations were performed using the polyurethane foam. The results are shown in Table 1.

[Examples 2 to 6, Comparative Examples 1 to 2]
A polyurethane foam was obtained in the same manner as in Example 1 except that the formulation was changed as shown in Table 1. Various evaluations were performed using the polyurethane foam. The results are shown in Table 1.

It was confirmed that the polyurethane foam of each example satisfying the requirements of the present invention has excellent heat insulating properties due to its low thermal conductivity, and further excellent in dimensional stability at high temperature and normal temperature.
On the other hand, the polyurethane foams of the comparative examples, which do not satisfy the requirements of the present invention, have poor dimensional stability.

11 Cell 12 Hole 13 Site generated during sample preparation

Claims (8)

A polyurethane foam having a plurality of cells, having a closed cell ratio of 80% or more, and having holes formed in at least a part of the cell membrane of the cell. The polyurethane foam according to claim 1, which is formed from a foamable urethane resin composition containing a polyol compound, a polyisocyanate compound, a flame retardant, a foaming agent, and a catalyst. The polyurethane foam according to claim 2, wherein the foamable urethane resin composition contains a cell opener containing at least one fine particle component selected from organic fine particles and inorganic fine particles. The polyurethane foam according to claim 2 or 3, wherein the foaming agent contains a hydrofluoroolefin. The invention according to any one of claims 1 to 4, wherein the total calorific value when heated for 5 minutes at a radiant heat intensity of 50 kW / m ² is 8 MJ / m ² or less in accordance with the ISO-5660 test method. Polyurethane foam. The invention according to any one of claims 1 to 5, wherein the maximum heat generation rate when heated for 5 minutes at a radiant heat intensity of 50 kW / m ² is 200 kW / m ² or less in accordance with the test method of ISO-5660. Polyurethane foam. The polyurethane foam according to any one of claims 1 to 6, wherein the sinking distance of the steel ball in the following thermal steel ball evaluation is 10 mm or less.
(Evaluation of hot steel balls)
(1) A polyurethane foam is cut into a cube having a side of 50 mm and used as a test piece.
(2) A steel ball having a diameter of 10.0 mm and a weight of 4.15 g is placed inside an electric furnace set at 800 ° C. and heated for 10 minutes or more.
(3) In an atmosphere of 23 ° C., the steel ball heated in (2) above is immediately placed on the center of the upper part of the test piece of (1) above, and is left to stand until the subduction of the steel ball is completed. Then, the cross section of the sufficiently cooled test piece is cut to measure the subduction distance and the melt diameter distance of the steel ball. The polyurethane foam according to any one of claims 1 to 7, which is formed by spraying a foamable urethane resin composition containing a polyol compound, a polyisocyanate compound, a flame retardant, a foaming agent, and a catalyst.

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