JP7330782B2 - polyisocyanurate foam - Google Patents

Description

The present invention relates to polyisocyanurate foams.

Conventionally, various polyisocyanurate foams (rigid urethane foams containing isocyanurate rings) have been proposed as materials for foam boards and the like (for example, Patent Documents 1 and 2).

JP 2006-321882 JP 2007-099822

Here, in order to improve the flame retardancy of rigid urethane foam, as described in Patent Document 1 and Patent Document 2, a method of including an isocyanurate ring in the structure (method of increasing the nurate conversion rate), Techniques such as adding a fuel are known. However, the present inventors have found that even if flame retardancy can be secured by simply increasing the nurate ratio and the amount of flame retardant in order to improve flame retardancy, high heat insulation and suitable compressive strength, flyability, and dimensional stability I got the knowledge that I could not realize the nature.

Accordingly, an object of the present invention is to provide a polyisocyanurate foam that has a good balance of high heat insulation, suitable compressive strength, flyability, and dimensional stability while ensuring flame retardancy.

As a result of multilateral verification, the present inventors focused on the nurate rate and the closed cell rate, and furthermore, by setting these to predetermined numerical ranges, while ensuring flame retardancy, high heat insulation and suitable The inventors have found that a polyisocyanurate foam having a good balance of compression strength, flyability and dimensional stability can be provided, and have completed the present invention.

Specifically, the present invention relates to a polyisocyanurate foam obtained by mixing and reacting a polyol, a polyisocyanate, a blowing agent and a trimerization catalyst as essential components,
Nurate rate is 30 to 40%,
The polyisocyanurate foam is characterized by having a closed cell rate of 75% or more.
Here, the nurate ratio may be 32 to 40%.
Further, the nurate ratio may be 34 to 40%.
Further, the polyisocyanurate foam further contains a flame retardant, and the polyisocyanurate foam contains 2 to 21% by mass of the flame retardant based on the solid content mass of the polyisocyanurate foam. may be
Further, the polyisocyanurate foam may contain 9 to 21% by mass of the flame retardant based on the solid mass of the polyisocyanurate foam.
Further, the polyisocyanurate foam may contain 9 to 17% by mass of the flame retardant based on the solid mass of the polyisocyanurate foam.
Also, the blowing agent may be a physical blowing agent.
Further, the polyol may have an average hydroxyl value of 400 to 600 mgKOH/g.

ADVANTAGE OF THE INVENTION According to this invention, the polyisocyanurate foam which has high heat insulation property, suitable compressive strength, friability, and dimensional stability in good balance can be provided, ensuring flame retardancy.

FIG. 1 is an infrared absorption spectrum chart of a foamed product according to Example 3. FIG.

<<Polyisocyanurate foam>>
The components and physical properties of the polyisocyanurate foam will be described in detail below. In addition, the numerical range "X to Y" in the present specification and claims means X or more and Y or less.

<Ingredients/Quantity>
Polyisocyanurate foams have isocyanurate rings in their molecular structure. Here, the degree of nulation is 30 to 40%, preferably 32 to 40%, more preferably 34 to 40%. In addition, the nurate conversion rate was measured based on the infrared absorption spectroscopy method, and the absorption peak area based on the nurate ring, the nurate ring, the NH of the urethane/urea, the C=O of the urea, the urethane/nurate It is a value obtained by dividing by the sum of absorption peak areas based on C═O to calculate the ratio of nurate rings to the entire partial structure (see, for example, FIG. 1).
More specifically, it is calculated as follows.
Nurate rate (%) = [a / (a + b + c + d)] × 100
a: Absorption peak position based on nurate ring: 1410 cm ^-1 , area position: area from 1347.03 to 1464.67 cm ^-1 b: Absorption peak position based on [NH] of urethane/urea: 1510 cm ^-1 , area Position: Area from 1460.81 to 1562.06 cm ^-1 c: Absorption peak position based on [C=O] of urea: 1595 cm ^-1 , Area position: Area from 1566.88 to 1638.23 cm ^-1 d: Urethane ・Absorption peak position based on [C=O] of nurate: 1710 cm ⁻¹ , area position: 1636.3 to 1768.4 cm ⁻¹ area Here, the nurate conversion rate of the polyisocyanurate foam is, for example, the polyisocyanate It is a value measured for a part cut out from the surface of the foam at a depth of 3 mm. When the nurate ratio is within the range and the closed cell ratio is within the range described later, flame retardancy is ensured, while high heat insulation, suitable compressive strength, flyability, and dimensional stability are well balanced. It becomes a polyisocyanurate foam having. The isocyanate index is preferably 150 or more in order to obtain this degree of nulation.

The polyisocyanurate foam may have flame retardants. Examples of the flame retardant include known flame retardants such as red phosphorus; phosphorous compounds such as ammonium polyphosphate, melamine phosphate and triphenylphosphine; melamine compounds such as melamine cyanurate and melamine; metal hydrates such as aluminum hydroxide and magnesium hydroxide; antimony compounds such as antimony trioxide and antimony pentoxide; Phosphate ester compounds such as phenol phosphate, cresyl di-2,6-xylenyl phosphate, tris(dichloropropyl) phosphate, tris(chloropropyl) phosphate, tris(tribromoneopentyl) phosphate; However, phosphoric acid ester compounds are preferred, and tris(chloropropyl) phosphate, triethyl phosphate, and tricresyl phosphate are particularly preferred. Here, the flame retardant preferably contains 2 to 21% by mass, more preferably 9 to 21% by mass, based on the solid content of the polyisocyanurate foam. % by mass is particularly preferred. When the amount of the flame retardant is within the above range, a polyisocyanurate foam having a good balance of higher heat insulation, more suitable compressive strength, flyability and dimensional stability while ensuring flame retardancy is obtained.

<Structure>
The closed cell ratio of the polyisocyanurate foam is 75% or more, preferably 80% or more, more preferably 82.5% or more. Although the upper limit is not particularly limited, it is, for example, 99%. As described above, when the closed cell ratio is within the range and the nurate ratio is within the range, flame retardancy is ensured, while high heat insulation and suitable compressive strength, flyability, and dimensional stability A polyisocyanurate foam having well-balanced properties is obtained. Here, the closed cell content is a value measured based on ASTM D2856.

<<Method for producing polyisocyanurate foam>>
A suitable polyisocyanurate foam is, for example, a polyol side foaming raw material liquid (polyol, catalyst, optional foam stabilizer, optional foaming aid, optional flame retardant) and an isocyanate component containing polyisocyanate and a physical blowing agent. Hereinafter, the manufacturing method will be described separately for raw materials and processes (note that the flame retardant has been described above and will be omitted). In the following description, "polyol-side foaming raw material liquid" refers to a liquid containing a polyol, a catalyst, a foam stabilizer as an optional component, a foaming aid as an optional component, and a flame retardant as an optional component. The "composition" is a combination of the "polyol-side foaming raw material liquid" and the "isocyanate component". In addition, the "solid content mass of the polyisocyanurate foam" referred to in the claims and this specification is the mass of the polyisocyanate foam in which the internal foaming agent is completely replaced with air, and specifically In this, the polyisocyanate foam is made to communicate by crushing and crushing (with a closed cell rate of 0%), 23 (± 5) ° C., and a relative humidity of 50 (+20-10)%. The weight is approximately the same as the weight after being left for 16 hours or more. In this example, the solid content mass of the polyisocyanurate foam was approximately the same as the weight of the foaming raw material composition (that is, the weight of all raw materials - the weight of the foaming agent), and water as a foaming aid was added. If not used, it is understood to be exactly the same.

<raw materials>
(polyol)
The polyol is not particularly limited as long as it is a compound having multiple hydroxyl groups. For example, a combination of an aromatic polyester polyol having two or more hydroxyl groups at the terminal or side chain obtained by condensing a bifunctional or trifunctional polyether polyol with a polybasic acid. It is preferable to use The preferred embodiment will be described in detail below. Examples of polyols constituting bifunctional or trifunctional polyether polyols include bifunctional polyols (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, butanediol, pentanediol, neopentyl Glycol, hexanediol, cyclohexanedimethanol, bisphenol A, bisphenol F, bisphenol S, etc., or compounds obtained by addition polymerization of alkylene oxides such as ethylene oxide or propylene oxide, polyethylene glycol, polypropylene glycol, etc.), trifunctional polyols ( trimethylolpropane, glycerin, etc., or compounds obtained by addition polymerization of alkylene oxides thereto). You may use these 1 type or in combination of 2 or more types. Examples of polybasic acids constituting aromatic polyester polyols include orthophthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid, tetrahydrophthalic acid, trimellitic acid, and pyromellitic acid. Here, polyester polyols obtained by condensing phthalic acid with one or more of difunctional, trifunctional or polyfunctional alcohols or alkylene oxide adducts thereof are preferable, more preferably terephthalic acid and It is a polyester polyol obtained by condensation with diethylene glycol. The content of hydroxyl groups in the aromatic polyester polyol is 2 or more, preferably 2 to 3.

Here, the average hydroxyl value of the polyol is preferably 300 mgKOH/g or more, and although the upper limit is not particularly limited, it is, for example, 1200 mgKOH/g. More specifically, the average hydroxyl value of the polyol is particularly preferably 400-600 mgKOH/g. When the average hydroxyl value of the polyol is in this range, a polyisocyanurate foam having higher heat insulating properties and more suitable compressive strength, flyability and dimensional stability while ensuring flame retardancy is obtained. Here, the average hydroxyl value is a value measured according to JIS K1557-1 (Plastics-Polyurethane raw material polyol test method-Part 1: Determination of hydroxyl value).

(physical blowing agent)
Physical blowing agents are preferably, but not limited to, hydrocarbons (preferably C4-C6) and hydrofluoroolefins. Specific examples include cyclopentane, HFO (1336mzz), and HFO (1233zd).

(foaming aid)
Although the foaming aid is not particularly limited, it is preferably water. The problem can be achieved by using a physical blowing agent alone, but even if a predetermined amount of blowing aid is added, a wide range of heat insulation properties, compression strength, flyability, and dimensional stability can be achieved while ensuring flame retardancy. A foam having well-balanced properties can be obtained. Here, when water is used as a foaming assistant, the amount of the physical foaming agent (for example, cyclopentane) added is preferably 3.0 to 15 parts by weight with respect to 100 parts by weight of the foaming material composition. As for the number of parts of water to be added, it is preferable that the amount blended in the foaming material composition is 0.05 parts by weight or less based on 100 parts by weight of the foaming material composition. When the proportion of water is 0.05 parts by weight or less, it is possible to obtain a foam that is not brittle, has good adhesiveness to a surface material, etc., and has high heat insulating properties.

(catalyst)
The catalyst essentially includes a trimerization catalyst. A mixed catalyst of a trimerization catalyst, a resinification catalyst, and a foaming catalyst is preferable, and a mixed catalyst of a metal salt catalyst and an amine catalyst is preferable. Examples of trimerization catalysts include: 1) metal oxides such as lithium oxide, sodium oxide and potassium oxide; 2) methoxysodium, ethoxysodium, propoxysodium, butoxysodium, methoxypotassium, ethoxypotassium and propoxypotassium. , alkoxides such as potassium butoxy; 3) organic metal salts such as potassium acetate, potassium octylate, potassium caprylate, iron oxalate; 4) 2,4,6-tris(dimethylaminomethyl)phenol, N,N' ,N″-tris(dimethylaminopropyl)hexahydrotriazine, triethylenediamine and other tertiary amines; 5) derivatives of ethyleneimine; 6) acetylacetone chelates of alkali metals, aluminum and transition metals, quaternary ammonium salts These can be used alone or in combination of two or more, and among them, organic metal salts and quaternary ammonium salts are more preferably used. Potassium octylate and potassium octylate are used in combination.The resin-forming or foaming catalyst is not particularly limited, and those used in the production of ordinary urethane foam can be used, for example, monoamines (N, N-dimethylcyclohexylamine, N,N-dicyclohexylmethylamine, triethylamine, N,N-dimethylbenzylamine, etc.), cyclic monoamines (pyridine, N-methylmorpholine, N-ethylmorpholine, etc.), diamines (N , N,N′,N′-tetramethylethylenediamine, N,N,N′,N′-tetramethyl-1,3-propanediamine, N,N,N′,N′-tetramethyl-1,3- butanediamine, N,N,N',N'-tetramethylhexanediamine, methylene-bis(dimethylcyclohexylamine), N,N,N',N'-tetraethylethylenediamine, etc.), triamines (N,N,N ',N',N''-pentamethyldiethylenetriamine, N,N,N',N',N''-pentamethyldipropylenetriamine, 2,4,6-tris(dimethylaminomethyl)-phenol, etc.), ether diamine (bis(2-dimethylaminoethyl) ether, 2-(N ,N-dimethylamino)ethyl-3-(N,N-dimethylamino)propyl ether, 4,4′-oxydimethylenedimorpholine, etc.), Cyclic polyamines (triethylenediamine, N,N'-dimethylpiperazine, N,N'-diethylpiperazine, N,N-dimethylaminoethylmorpholine, 1-isobutyl-2-methylimidazole, 1-butoxy-2-methylimidazole etc.), alkanolamines (N,N,N'-trimethylaminoethylethanolamine, N,N,N'-trimethylaminopropylethanolamine, 2-(2-dimethylamino-ethoxy)ethanol, N,N-dimethyl Amine catalysts such as aminoethanol, N,N-trimethyl-1,3-diamino-2-propanol, N-methyl-N'-(2-hydroxyethyl)-piperazine, etc.). These catalysts may be used singly or in combination of two or more.

(other additive ingredients)
When producing the polyisocyanurate foam, various additives such as a foam stabilizer, a viscosity reducer, a surface material adhesion improver, and a cell refiner may be further used. At this time, these additives may be added when the polyol-side foaming raw material liquid and the polyisocyanate component are mixed, or may be included in the polyol-side foaming raw material liquid in advance. As the foam stabilizer, conventionally known nonionic surfactants, silicone surfactants and the like can be used.

(polyisocyanate)
Preferred polyisocyanates are aromatic polyisocyanate compounds. Examples include phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, dimethyldiphenylmethane diisocyanate, triphenylmethane triisocyanate, naphthalene diisocyanate, and polymethylene polyphenyl polyisocyanate. The above aromatic polyisocyanate compounds may be used alone, or two or more of them may be used as a mixture.

<Process>
The polyisocyanurate foam is obtained by mixing the polyol-side foaming material liquid, the polyisocyanate component, and the physical foaming agent, followed by foaming and curing. For example, it can be obtained by using a general-purpose high-pressure foaming machine or the like to perform collision mixing to obtain a mixed liquid, which is put into a mold of a predetermined size or the like and foamed and hardened. A low-pressure injection machine is used for continuous molding, and a flat plate, slabstock, etc. can be molded by discharging onto a belt conveyor at normal temperature and atmospheric pressure. As for the basic manufacturing method, those shown in Patent Document 1 and Patent Document 2 are applied. However, the following are features that should be noted.

(isocyanate index)
When the polyol-side foaming raw material liquid and the polyisocyanate component are mixed, the isocyanate index of the mixture (foaming raw material composition) is preferably 150 to 600, more preferably 350 to 600, and even more preferably 370. ~550. Within this range, a polyisocyanate foam having a good balance of higher heat insulation properties, more suitable compressive strength, flyability, and dimensional stability while ensuring flame retardancy is obtained. Here, the isocyanate index refers to the ratio of the number of moles of all active hydrogens in the reaction mixture containing all raw materials to the number of moles of isocyanate groups in the polyisocyanate compound (molar ratio of NCO/OH). Moreover, OHV in the following examples and comparative examples indicates a hydroxyl value. Here, when a plurality of polyols are added, the weighted average obtained by multiplying each hydroxyl value by the number of parts added and divided by the total number of parts added of all polyols is taken as the average hydroxyl value (average OHV).

(Viscosity of polyisocyanate component)
The 25° C. viscosity of the polyisocyanate component is preferably 150 to 750 mPa·s. Here, the viscosity is measured according to ASTM D4889.

≪Manufacturing example≫
(Example 1)
As a polyester polyol, 100 parts by weight of a polyester polyol obtained by dehydration condensation of orthophthalic acid and diethylene glycol (DEG) (OHV 400 mgKOH/g, weight average molecular weight 510); and as a polyether polyol, diethylene glycol ( DEG) 14.1 parts by weight and triethylene glycol (TEG) 2.0 parts by weight; furthermore, a foam stabilizer, a catalyst and a flame retardant were added to obtain a polyol-side foaming raw material liquid. The average hydroxyl value (average OHV) of the polyols (all polyols) contained in the above polyol-side foaming raw material liquid was 490 mgKOH/g.
Here, as the foam stabilizer, trade name: Niax Silicone L-6638 (manufactured by Momentive) 0.9% by mass and methyl carbitol (manufactured by Sankyo Chemical Co., Ltd.) based on the total mass of the foaming raw material composition name: methyl diglycol) was added so as to be 0.6% by mass. As the catalyst, based on the total mass of the foaming material composition, 0.6% by mass and 0.3% by mass of potassium octylate and potassium acetate as trimerization catalysts, and Lubeac DMP-30 (manufactured by Nacalai Tesque). It added so that it might become 0.3 mass %. Furthermore, as the flame retardant, tris(1-chloro-2-propyl)phosphate (TCPP) (trade name: ProFlame-PC1389, manufactured by Pro Flame) is added at 16% by mass based on the total mass of the foaming raw material composition. was added so that
After weighing the polyol-side foaming raw material liquid, it was stirred for 1 minute with a propeller stirrer at 3000 rpm. After that, an isocyanate component (Crude MDI trade name: MR-200 manufactured by Tosoh Corporation), which was similarly temperature-controlled to 15°C, was added to the polyol-side foaming raw material liquid whose temperature was controlled to 15°C so that the isocyanate index was 250. Furthermore, cyclopentane (trade name: Marukasol FH, manufactured by Maruzen Oil Co., Ltd.) was added as a physical foaming agent so as to be 6.5% by mass with respect to the total mass of the foaming material composition. These mixtures were rapidly stirred for 10 seconds with a propeller stirrer at 5000 rpm to obtain a stirred product. After that, the stirred material was put into a mold frame of 300×300×20 mm provided with aluminum face materials on the top and bottom to prepare a laminate board with aluminum face materials on the top and bottom surfaces. Further, the agitated material was placed in a box of 300×300×300 mm with an open top to prepare a foam without a face material (hereinafter referred to as a free foam product). The density of the foam produced at this time was 30.7 kg/m ³ .

(Example 2)
As a polyester polyol, 100 parts by weight of a polyester polyol (OHV 323 mgKOH / g, weight average molecular weight 490) obtained by dehydration condensation of orthophthalic acid and diethylene glycol (DEG) was added. 17.1 parts by weight of diethylene glycol (DEG) and 2.0 parts by weight of triethylene glycol (TEG) were added, the average hydroxyl value (average OHV) of the polyol was 435 mg KOH / g, and the isocyanate index was 370 A laminate board having aluminum face materials on the upper and lower surfaces was prepared in the same manner as in Example 1, except that the isocyanate component was added so that Also, the density of the free-foamed product was 31.6 kg/m ³ .

(Example 3)
19.3 parts by weight of diethylene glycol (DEG) was added to 100 parts by weight of polyester polyol, the average OHV of the polyol was 518 mgKOH/g, and the isocyanate component was added so that the isocyanate index was 450. A laminate board having aluminum face materials on the upper and lower surfaces was prepared in the same manner as in Example 1. Also, the density of the free-foamed product was 34.2 kg/m ³ . In addition, FIG. 1 is a light absorption spectrum chart of the foamed product according to Example 3 (the nurate ratio is calculated from the chart).

(Example 4)
20.9 parts by weight of diethylene glycol (DEG) was added to 100 parts by weight of polyester polyol, the average OHV of the polyol was 526 mgKOH/g, and the isocyanate component was added so that the isocyanate index was 500. prepared a laminate board having aluminum facings on the upper and lower surfaces in the same manner as in Example 1. Also, the density of the free-foamed product was 27.7 kg/m ³ .

(Example 5)
24.9 parts by weight of diethylene glycol (DEG) was added to 100 parts by weight of the polyester polyol, the average OHV of the polyol was 534 mgKOH / g, the amount of the flame retardant added was 10% by mass, and further, A laminate board having aluminum face materials on the upper and lower surfaces was prepared in the same manner as in Example 1, except that the isocyanate component was added so that the isocyanate index was 600. Also, the density of the free-foamed product was 33.4 kg/m ³ .

(Example 6)
17.2 parts by weight of diethylene glycol (DEG) was added to 100 parts by weight of the polyester polyol, the average OHV of the polyol was 507 mgKOH / g, the amount of the flame retardant added was 3% by mass, and further, A laminate board having aluminum face materials on the upper and lower surfaces was prepared in the same manner as in Example 1, except that the isocyanate component was added so that the isocyanate index was 450. Also, the density of the free-foamed product was 35.1 kg/m ³ .

(Example 7)
20.7 parts by weight of diethylene glycol (DEG) was added to 100 parts by weight of the polyester polyol, the average OHV of the polyol was 525 mgKOH / g, the amount of the flame retardant added was 9% by mass, and further, A laminate board having aluminum face materials on the upper and lower surfaces was prepared in the same manner as in Example 1, except that the isocyanate component was added so that the isocyanate index was 550. Also, the density of the free-foamed product was 30.5 kg/m ³ .

(Example 8)
18.3 parts by weight of diethylene glycol (DEG) was added to 100 parts by weight of the polyester polyol, the average OHV of the polyol was 513 mgKOH / g, the amount of the flame retardant added was 10% by mass, and further, A laminate board having aluminum face materials on the upper and lower surfaces was prepared in the same manner as in Example 1, except that the isocyanate component was added so that the isocyanate index was 450. Also, the density of the free-foamed product was 35.6 kg/m ³ .

(Example 9)
20.2 parts by weight of diethylene glycol (DEG) was added to 100 parts by weight of the polyester polyol, the average OHV of the polyol was 522 mgKOH / g, the amount of the flame retardant added was 20% by mass, and further, A laminate board having aluminum face materials on the upper and lower surfaces was prepared in the same manner as in Example 1, except that the isocyanate component was added so that the isocyanate index was 450. Also, the density of the free-foamed product was 33.2 kg/m ³ .

(Example 10)
18.3 parts by weight of diethylene glycol (DEG) was added to 100 parts by weight of polyester polyol, the average OHV of the polyol was 513 mgKOH/g, the amount of the flame retardant added was 10% by mass, physical foaming In the same manner as in Example 1, except that a hydrofluoroolefin product name: Soltis 1233zd (HFO) manufactured by Honeywell was used as the agent, and an isocyanate component was added so that the isocyanate index was 450. , a laminate board with aluminum facings on the top and bottom surfaces was created. Also, the density of the free-foamed product was 36.8 kg/m ³ .

(Example 11)
18.05 parts by weight of diethylene glycol (DEG) was added to 100 parts by weight of polyester polyol, the average OHV of the polyol was 438 mgKOH/g, the amount of physical blowing agent was changed, and water was used as a blowing aid. was added in a predetermined amount, and furthermore, an isocyanate component was added so that the isocyanate index was 450, in the same manner as in Example 1. . Also, the density of the free-foamed product was 33.6 g/m ³ .

(Example 12)
As a polyester polyol, 100 parts by weight of a polyester polyol (OHV 250 mgKOH / g, weight average molecular weight 830) obtained by dehydration condensation of terephthalic acid and diethylene glycol (DEG) was added. 26.9 parts by weight of diethylene glycol (DEG) and 2.0 parts by weight of triethylene glycol (TEG) were added, the average hydroxyl value (average OHV) of the polyol was 426 mg KOH / g, and the isocyanate index was 370. A laminate board having aluminum face materials on the upper and lower surfaces was prepared in the same manner as in Example 1, except that an isocyanate component was added. Also, the density of the free-foamed product was 33.2 kg/m ³ .

(Comparative example 1)
109.4 parts by weight of diethylene glycol (DEG) was added to 100 parts by weight of polyester polyol, the average OHV of the polyol was 743 mgKOH/g, the amount of physical blowing agent was changed, and water was used as a blowing aid. was added in a predetermined amount, and furthermore, an isocyanate component was added so that the isocyanate index was 450, in the same manner as in Example 1. . Also, the density of the free foam product was 36.1 kg/m ³ .

(Comparative example 2)
13.0 parts by weight of diethylene glycol (DEG) was added to 100 parts by weight of polyester polyol, the average OHV of the polyol was 483 mgKOH/g, and an isocyanate component was added so that the isocyanate index was 200. A laminate board having aluminum facings on the upper and lower surfaces was produced in the same manner as in Example 1 except for the above. Also, the density of the free-foamed product was 36.8 kg/m ³ .

(Comparative Example 3)
27.2 parts by weight of diethylene glycol (DEG) was added to 100 parts by weight of polyester polyol, a polyol having an average OHV of 551 mgKOH/g was used, and an isocyanate component was added so that the isocyanate index was 650. A laminate board having aluminum face materials on the upper and lower surfaces was produced in the same manner as in Example 1, except that the above was used. Also, the density of the free-foamed product was 31.2 kg/m ³ .

≪Evaluation≫
(oxygen index)
Samples were taken from the free-foaming products, and the oxygen index was measured according to JIS K7201-2. Specifically, the test was performed in a transparent column in which a mixed gas of oxygen and nitrogen flowed upward in a laminar flow, and a flame was brought into contact with the upper end of the test piece for up to 30 seconds to determine whether the test piece was burning. confirm. The determination of combustion behavior is based on the combustion time and combustion length after ignition. Since the shape of the test piece this time corresponds to type II, the burning time is 180 seconds and the burning length is 50 mm below the top of the test piece. The presence/absence of combustion behavior is measured in increments of 0.1% oxygen concentration, and the minimum oxygen concentration (=oxygen index) that maintains combustion is determined by the up-and-down method.

(Thermal conductivity)
Samples were taken from the laminate board product, and the thermal conductivity was measured based on JIS A9521.

(compressive strength)
It was collected from the free-foaming product, and the compressive strength was measured based on JIS A9521. Specifically, a sample cut to 100 × 100 × 20 mm was sandwiched between the centers of two pressure plates of a tester, and the test piece was compressed at a speed of 2 mm / min to reach a compression deformation rate of 10%. The maximum force at that time was taken as the compressive strength.

(fly ability)
Samples were taken from free-foaming products, and flyability was measured according to ASTM-C-421-61. Specifically, the weight of 12 samples cut to 25 x 25 x 25 mm was measured, placed in a measuring instrument together with 24 pieces of wood (19 ± 0.8 mm), and after 600 rotations, scraped powder was dropped and tested. Measure the weight after. Based on the original weight, the reduced weight was calculated in 100% and taken as flyability (=weight reduction rate).

(Dimensional stability)
A sample of 100×100×20 mm was taken from the free-foaming product and cut into 100×100×20 mm.

≪Evaluation Criteria≫
The evaluation criteria for each item are shown below. The order of evaluation is AA>A>B>C>D. Here, D evaluation is not a practical level and is unsuitable as a product.

(oxygen index)
29% or more AA
27% or more and less than 29% A
24% or more and less than 27% B
22% or more and less than 24% C
Less than 22% D

(Thermal conductivity)
Less than 21mW/m・K A
21 mW/m・K or more and less than 22 mW/m・K B
22 mW/m・K or more and less than 23 mW/m・K C
23mW/m・K or more D

(compressive strength)
15N/ ^cm2 or more A
8 N/cm ² or more and less than 15 N/cm ² C

(fly ability)
65% or less A
Over 65% C

(Dimensional stability)
Less than 3.0% A
3.0% or more C

Table 1 (Table 1A and Table 1B) shows the formulation composition of each example and comparative example, the nurate rate and the closed cell rate, and the above evaluation items (oxygen index, thermal conductivity, compressive strength, flyability, dimensional stability It shows ) and . Here, the overall evaluation is AA 4 points, A 3 points, B 2 points, C 1 point, oxygen index points x 3 + thermal conductivity points x 3 + compressive strength points + flyability points. + is the sum of the dimensional stability points. In addition, when there was D evaluation even in one item, it was recognized as a defective product.

Claims (5)

In the polyisocyanurate foam obtained by mixing and reacting polyol, polyisocyanate, blowing agent and trimerization catalyst as essential components,
The rate calculated by the following calculation method is 30 to 40%,
The closed cell rate is 75% or more,
The polyisocyanurate foam further contains a flame retardant,
A polyisocyanurate foam containing 9 to 21% by mass of the flame retardant based on the solid content of the polyisocyanurate foam.
( calculation method)
Based on what was measured based on the infrared absorption spectrum method, according to the following formula, the absorption peak area based on the nurate ring, the nurate ring, the NH of the urethane/urea, the C=O of the urea, the C of the urethane/nurate = Calculated by dividing by the sum of absorption peak areas based on O:
Rate (%) = [a/(a+b+c+d)] x 100
a: Absorption peak position based on nurate ring: 1410 cm ^-1 , area position: area from 1347.03 to 1464.67 cm ^-1 b: Absorption peak position based on [NH] of urethane/urea: 1510 cm ^-1 , area Position: Area from 1460.81 to 1562.06 cm ^-1 c: Absorption peak position based on [C=O] of urea: 1595 cm ^-1 , Area position: Area from 1566.88 to 1638.23 cm ^-1 d: Urethane ・Absorption peak position based on [C=O] of nurate: 1710 cm ^-1 , area position: area of 1636.3 to 1768.4 cm ^-1 In the polyisocyanurate foam obtained by mixing and reacting polyol, polyisocyanate, blowing agent and trimerization catalyst as essential components,
The rate calculated by the following calculation method is 30 to 40%,
The closed cell rate is 75% or more,
A polyisocyanurate foam, wherein the polyol has an average hydroxyl value of 400 to 600 mgKOH/g.
( calculation method)
Based on what was measured based on the infrared absorption spectrum method, according to the following formula, the absorption peak area based on the nurate ring, the nurate ring, the NH of the urethane/urea, the C=O of the urea, the C of the urethane/nurate = Calculated by dividing by the sum of absorption peak areas based on O:
Rate (%) = [a/(a+b+c+d)] x 100
a: Absorption peak position based on nurate ring: 1410 cm ^-1 , area position: area from 1347.03 to 1464.67 cm ^-1 b: Absorption peak position based on [NH] of urethane/urea: 1510 cm ^-1 , area Position: Area from 1460.81 to 1562.06 cm ^-1 c: Absorption peak position based on [C=O] of urea: 1595 cm ^-1 , Area position: Area from 1566.88 to 1638.23 cm ^-1 d: Urethane ・Absorption peak position based on [C=O] of nurate: 1710 cm ^-1 , area position: area of 1636.3 to 1768.4 cm ^-1 In a polyisocyanurate foam obtained by mixing and reacting a foaming raw material composition containing a polyol, a polyisocyanate, a blowing agent and a trimerization catalyst as essential components,
The rate calculated by the following calculation method is 30 to 40%,
The closed cell ratio is 75% or more and 87.3% or less,
the blowing agent is a physical blowing agent,
A polyisocyanurate foam, wherein the amount of water blended in the foaming material composition is 0.05 parts by weight or less based on 100 parts by weight of the foaming material composition.
( calculation method)
Based on what was measured based on the infrared absorption spectrum method, according to the following formula, the absorption peak area based on the nurate ring, the nurate ring, the NH of the urethane/urea, the C=O of the urea, the C of the urethane/nurate = Calculated by dividing by the sum of absorption peak areas based on O:
Rate (%) = [a/(a+b+c+d)] x 100
a: Absorption peak position based on nurate ring: 1410 cm ^-1 , area position: area from 1347.03 to 1464.67 cm ^-1 b: Absorption peak position based on [NH] of urethane/urea: 1510 cm ^-1 , area Position: Area from 1460.81 to 1562.06 cm ^-1 c: Absorption peak position based on [C=O] of urea: 1595 cm ^-1 , Area position: Area from 1566.88 to 1638.23 cm ^-1 d: Urethane ・Absorption peak position based on [C=O] of nurate: 1710 cm ^-1 , area position: area of 1636.3 to 1768.4 cm ^-1 The polyisocyanurate foam further contains a flame retardant,
4. The polyisocyanurate foam according to claim 2, wherein the polyisocyanurate foam contains 2 to 21% by mass of the flame retardant based on the solid content of the polyisocyanurate foam. A foam board comprising the polyisocyanurate foam according to any one of claims 1-4.

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