JP2009040905A - Polyisocyanate for producing rigid polyurethane foam and method for producing rigid polyurethane foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide polyisocyanate for use in producing a rigid polyurethane foam having an excellent balance between bondability and dimensional stability, and a method for producing the rigid polyurethane foam. <P>SOLUTION: The polyisocyanate for use in producing a rigid polyurethane foam comprises 85-99.7 parts by mass of a polymeric diphenylmethane diisocyanate and 0.3-15 parts by mass of either or both selected from among aliphatic isocyanates and alicyclic isocyanates. Preferably, the polyisocyanate is used in combination with water as a blowing agent. The either or both selected from among aliphatic isocyanates and alicyclic isocyanates preferably are either or both of hexamethylene diisocyanate and a modification thereof. The polyisocyanate preferably has viscosity at 25°C of 200 mPa s or lower. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polyisocyanate for producing a rigid polyurethane foam and a method for producing a rigid polyurethane foam.

  Rigid polyurethane foams are widely used mainly in the fields of building materials such as inner wall materials, outer wall materials, doors, panels, and the like in houses and in fields where heat insulation properties such as refrigerators and the like to which a cold insulation material is attached are required.

Rigid polyurethane foam is produced by stirring and mixing a polyol and a polyisocyanate in the presence of a catalyst and a foaming agent, reacting and foaming. At this time, auxiliary materials such as a foam stabilizer, a flame retardant, and an auxiliary agent are appropriately added.
Conventionally, chlorofluorocarbons have been widely used as foaming agents used in the production of rigid polyurethane foams. However, due to environmental problems, replacement with hydrofluorocarbon not containing chlorine, water, or the like is being promoted.

  However, when hydrofluorocarbon or water is used as a foaming agent, the brittleness of the surface of the urethane foam increases, and various problems such as the mechanical properties and moldability of the polyurethane foam, and the adhesion to adherends such as building materials decrease. There is.

In order to improve these problems, for example, by using a specific imidazole catalyst, a method of obtaining a polyurethane foam having excellent moldability and resistance to yellowing without impairing the resin strength during demolding has been proposed. (See Patent Document 1).
In addition, by using polyols including phthalic polyester polyols and specific auxiliaries, the mixability and flowability of the stock solution during the foaming reaction are improved, and the dimensions have initial and permanent adhesive strength during foam foaming. A method for obtaining a polyisocyanurate foam having good stability and flame retardancy has been proposed (see Patent Document 2).
Moreover, the method of obtaining the rigid polyurethane foam which has improved the brittleness and has the outstanding adhesiveness with a face material by using a specific modifier is proposed (refer patent document 3).
In addition, as a polyisocyanate component, a binuclear diphenylmethane diisocyanate (pureadiphenylmethane diisocyanate, hereinafter referred to as pure MDI) and a trinuclear or higher diphenylmethane diisocyanate (polymeric diphenylmethane diisocyanate, hereinafter referred to as polymeric MDI). A method of obtaining a polyurethane foam having a low brittleness and particularly excellent tensile properties in a low temperature range has been proposed (see Patent Document 4).
JP-A-9-87351 JP 2002-363241 A JP 2004-107613 A JP 2007-2118 A

However, none of the above-described conventional techniques necessarily provide good adhesiveness, and it seems that the adhesiveness is not always sufficient when constructed in winter, particularly in cold regions.
In addition, among the above-described conventional techniques, for example, those whose adhesion is improved by adding an auxiliary agent, the dimensional stability of the foam is poor, in other words, the balance between the adhesiveness and the dimensional stability seems to be poor. It is. In this case, the low dimensional stability means that, for example, in the process of using the foam in a state where the foam is adhered to the wall for a long period of time, the foam shrinks and peels off from the wall. In terms of meaning, it is not preferable.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a polyisocyanate for producing a rigid polyurethane foam excellent in the balance between adhesiveness and dimensional stability of the obtained foam and a method for producing the rigid polyurethane foam. And

The polyisocyanate for producing a rigid polyurethane foam according to the present invention is a polyisocyanate for producing a rigid polyurethane foam used for producing a rigid polyurethane foam by reacting with a polyol in the presence of a catalyst and a foaming agent.
It consists of 85 to 99.7 parts by mass of polymeric diphenylmethane diisocyanate and either or both of 0.3 to 15 parts by mass selected from aliphatic isocyanates and alicyclic isocyanates.

  The polyisocyanate for producing a rigid polyurethane foam according to the present invention is preferably characterized in that the foaming agent is water.

  The polyisocyanate for producing a rigid polyurethane foam according to the present invention is preferably any one or both of the aliphatic isocyanate and the alicyclic isocyanate selected from the group consisting of hexamethylene diisocyanate and a modified product thereof. Or one or both.

  The polyisocyanate for producing a rigid polyurethane foam according to the present invention is preferably characterized in that the polyisocyanate has a viscosity at 25 ° C. of 200 mPa · s or less.

  The method for producing a rigid polyurethane foam according to the present invention uses the above-mentioned polyisocyanate for producing a rigid polyurethane foam in the method for producing a rigid polyurethane foam in which a polyol and a polyisocyanate are reacted in the presence of a catalyst and a foaming agent. Features.

The polyisocyanate for producing a rigid polyurethane foam according to the present invention comprises 85 to 99.7 parts by mass of polymeric diphenylmethane diisocyanate and one or both of 0.3 to 15 parts by mass selected from aliphatic isocyanate and alicyclic isocyanate. Therefore, it is excellent in the balance between the adhesiveness and dimensional stability of the foam obtained, and is suitable for use by adhering the foam to a building material, a heat insulating device or other base material.
Moreover, since the manufacturing method of the rigid polyurethane foam which concerns on this invention uses said polyisocyanate for rigid polyurethane foam manufacture, the effect of the said invention can be acquired suitably.

  Embodiments of the present invention will be described below.

The polyisocyanate for producing a rigid polyurethane foam according to the present embodiment is used for producing a rigid polyurethane foam by reacting with a polyol in the presence of a catalyst and a foaming agent.
The polyisocyanate for producing rigid polyurethane foam according to the present embodiment (hereinafter sometimes simply referred to as polyisocyanate according to the present embodiment) is composed of 85 to 99.7 parts by mass of polymeric diphenylmethane diisocyanate, aliphatic isocyanate, It consists of 0.3-15 mass parts of either one or both chosen from alicyclic isocyanate.

  The polyisocyanate according to the present embodiment may be prepared in advance as a mixture (formulation) prior to foam production, and is selected from polymeric diphenylmethane diisocyanate, aliphatic isocyanate and alicyclic isocyanate. Either one or both of them may be stored separately in this ratio, and blended together with other raw materials during foam production.

Here, the influence on the foam characteristics by considering the composition of the polyisocyanate as described above will be considered.
Polymeric diphenylmethane diisocyanate (hereinafter sometimes referred to as “polymeric MDI”), which is usually used to obtain good heat insulation, has high reactivity. For example, in the case of forming a foam in a short period of time on site construction, etc. Although it is preferable, the curing and foaming of the foam is completed before the polyisocyanate is uniformly diffused over the entire surface of the substrate in the process of mixing with other raw materials, stirring, and applying to the substrate, so-called wettability is impaired. There is a fear.
On the other hand, when an appropriate amount of aliphatic isocyanate or alicyclic isocyanate is blended with polymeric MDI as the main component, the reactivity of aliphatic isocyanate and alicyclic isocyanate is lower than the reactivity of polymeric MDI. In the process of mixing, stirring and applying to the base material, the foam is cured in a state where the polyisocyanate is uniformly diffused over the entire surface of the base material, so that a foam with good wettability may be obtained. Conceivable.

The polymeric MDI used is a practically available mixture of benzene dinuclear and benzene polynuclear (crude MDI). In this case, the mixture (crude MDI) may be a practically available polymeric MDI alone, or a practically available polymeric MDI and pure MDI containing only benzene dinuclear. It may be. Content of the benzene dinuclear body in polymeric MDI (crude MDI) is not specifically limited, For example, you may contain in 10-80 mass%, Preferably it is 20-60 mass%.
Further, in the present embodiment, the use of MDI consisting only of benzene polynuclear bodies is not excluded. Further, a polymer MDI partially modified with a polyol or the like may be used.

  The aliphatic isocyanate or alicyclic isocyanate used together with the polymeric MDI is one or both (mixture) selected from aliphatic polyisocyanate and alicyclic polyisocyanate as described above. The type of the aliphatic polyisocyanate is not particularly limited, but any one or both selected from hexamethylene diisocyanate (HDI) and a modified product thereof can be preferably used. The type of the alicyclic polyisocyanate is not particularly limited, but either or both selected from isophorone diisocyanate (IPDI) and a modified product thereof can be preferably used. From the viewpoint of availability, it is preferable to use an aliphatic isocyanate.

  By using the polyisocyanate having the composition according to the present embodiment, it is possible to obtain a rigid polyurethane foam having both good adhesion and dimensional stability and excellent balance between the two. That is, when water is used as the foaming agent, a rigid polyurethane having a peel strength at an adhesion temperature of 0 ° C. in an adhesion test of 4 (unit: N / 7 cm) or more and a volume shrinkage in a dimensional stability evaluation test of 5% or less. A form can be obtained. In addition, when the ratio of polymeric MDI is extremely large, there is a possibility that the adhesiveness may be lowered. On the other hand, when the ratio of aliphatic isocyanate or alicyclic isocyanate is extremely large, the dimensional stability may be lowered.

  The polyisocyanate according to the present embodiment preferably has a viscosity at 25 ° C. of 200 mPa · s or less. Here, the viscosity is a value obtained by measuring with a B-type rotational viscometer.

Rigid polyurethane foams include slab foam (cutting board), injection foam, laminate, sandwich panel and spray foam (in situ foam).
The polyisocyanate according to the present embodiment described so far can be applied to any of the above, but among them, as described above, it can be suitably applied by spray foaming that requires construction in a short time. .
Further, by using a polyisocyanate having a viscosity at 25 ° C. of 200 mPa · s or less in spray foaming, the material is excellent in handling property in stirring and mixing operations, and is excellent in sprayability (uniform mixing).
Such a low-viscosity polyisocyanate blend is realized by including pure MDI or HDI having a low viscosity as a polyisocyanate component. The lower limit of the viscosity of the polyisocyanate compound is not limited, and the lower the value, the better as long as there is no problem such as impairing the physical properties of the foam.

  Below, the manufacturing method of the rigid polyurethane foam which concerns on this Embodiment is demonstrated. The method for producing a rigid polyurethane foam according to the present embodiment can exert its effect suitably by using the polyisocyanate according to the present embodiment.

That is, the method for producing a rigid polyurethane foam according to the present embodiment is a method for producing a rigid polyurethane foam in which a polyol and a polyisocyanate are reacted in the presence of a catalyst and a foaming agent. 7 parts by mass and either or both selected from aliphatic isocyanate and alicyclic isocyanate are blended at a ratio of 0.3 to 15 parts by mass.
Moreover, the manufacturing method of the rigid polyurethane foam which concerns on this Embodiment, Preferably, water is used as a foaming agent.
In the method for producing a rigid polyurethane foam according to the present embodiment, preferably, one or both selected from the aliphatic isocyanate and the alicyclic isocyanate to be used are hexamethylene diisocyanate and a modified product thereof. Either one or both.
Moreover, the manufacturing method of the rigid polyurethane foam which concerns on this Embodiment, Preferably, the viscosity in 25 degreeC of the polyisocyanate to be used is 200 mPa * s or less.

  In the method for producing a rigid polyurethane foam according to the present embodiment, a preferred isocyanate index [(mole number of all isocyanate groups in polyisocyanate composition / mole number of all active hydrogen groups in polyol) × 100] is 50 to 50. It is in the range of 500, more preferably in the range of 80 to 300.

  In the method for producing a rigid polyurethane foam according to the present embodiment, the type of catalyst used is not particularly limited, but promotes the reaction between the active hydrogen-containing group in the polyol and the isocyanate group in the organic polyisocyanate. Metal compound catalysts such as organotin compounds and 3 such as triethylenediamine (TEDA), tetramethylhexamethylenediamine (TMHMDA), pentamethyldiethylenetriamine (PMDETA), dimethylcyclohexylamine (DMCHA), bisdimethylaminoethyl ether (BDMAEA) A secondary amine catalyst is used. A trimerization catalyst for reacting isocyanate groups with each other is also used as necessary.

The type of foaming agent is not particularly limited, but the effect of the present invention can be obtained more suitably when water or hydrofluorocarbon is used in combination, or even when water is used alone. Can do.
In the case of water foaming, for example, about 3 to 10 parts by mass of water is blended with 100 parts by mass of the polyol component.

  In the present embodiment, a foam stabilizer is used for the purpose of forming good bubbles. Any foam stabilizer can be used as long as it is known as a foam stabilizer in the polyurethane industry. Examples thereof include silicone foam stabilizers and fluorine-containing compound foam stabilizers. Moreover, in this Embodiment, a filler, a stabilizer, a coloring agent, a flame retardant etc. can be used as an auxiliary | assistant further as needed. Typical examples of the flame retardant include tris (chloropropyl) phosphate (TCPP). For example, triethylene glycol dimethyl ether or dioctyl maleate is preferably used as an auxiliary agent.

In the present embodiment, a polyol that can react with an isocyanate group, that is, an active hydrogen compound having two or more active hydrogen-containing functional groups includes a compound having two or more active hydrogen-containing functional groups such as a hydroxyl group or an amino group, or Any known compound can be used as long as it is a mixture of two or more compounds.
Examples of the compound having two or more hydroxyl groups include polyether polyols, polyester polyols, polyhydric alcohols, and hydroxyl group-containing diethylene polymers. In particular, it is preferably composed of only one or more kinds of polyether-based polyols, or a combination of polyester-based polyols, polyhydric alcohols, polyamines, alkanolamines and other active hydrogen compounds based on them. The polyether polyol is preferably a polyhydric alcohol, a saccharide, an alkylamine, an alkanolamine, or a polyether polyol obtained by adding a cyclic ether, particularly an alkylene oxide such as propylene oxide or ethylene oxide, to other initiators. Also, a polyol composition in which fine particles of vinyl polymer are dispersed in a polyether-based polyol, which is called a polymer polyol or a graft polyol, can be used as the polyol. Polyester polyols include polyhydric alcohols, polyhydric carboxylic acid condensation polyols and cyclic ester ring-opening polymerization polyols. Polyhydric alcohols include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, triglyceride, Examples include methylolpropane, pentaerythritol, diethanolamine, and triethanolamine. Examples of the polyvalent carboxylic acid include phthalic anhydride, terephthalic acid, dimethyl terephthalic acid, adipic acid, and het acid. Of these, polyether polyols, polyester polyols, and mixtures thereof are more preferred.
The polyol used in the present embodiment is selected from those having a hydroxyl value of 20 to 700 KOHmg / g, preferably 100 to 400 KOHmg / g, depending on the use of the obtained rigid polyurethane foam, that is, various physical properties required. .

The present invention will be further described with reference to examples. In addition, this invention is not limited to the Example demonstrated below.
In the following description, each raw material is represented by a symbol or a trade name, and specific compound names, manufacturers, etc. are collectively shown after the description of the production method.

(Synthesis example of modified HDI "HDI-2")
950 g of hexamethylene diisocyanate (HDI-1) and 50 g of isopropanol were charged into a 1 L reactor equipped with a stirrer, a thermometer, a cooler, and a nitrogen gas introduction tube, and a urethanization reaction was performed at 90 ° C. for 2 hours. . When the reaction product was analyzed by FT-IR, the hydroxyl group had disappeared. Next, 0.2 g of zirconium 2-ethylhexanoate was charged and reacted at 90 ° C. for 3 hours. When the reaction product was analyzed by FT-IR and 13C-NMR, the urethane group had disappeared. Next, 0.1 g of phosphoric acid was added and a stop reaction was performed at 50 ° C. for 1 hour. The isocyanate content of the reaction product after the termination reaction was 42.1%. This reaction product was subjected to thin film distillation at 130 ° C./0.04 kPa, the isocyanate content was 19.4%, the viscosity at 25 ° C. was 101 mPa · s, the free hexamethylene diisocyanate content was 0.2%, the color number Was 10 APHA, and a polyisocyanate “HDI-2” having a bifunctional component of 73% was obtained. When "HDI-2" was analyzed by FT-IR and 13C-NMR, the presence of urethane groups was not recognized, and the presence of allophanate groups was confirmed. Further, traces of uretdione groups and isocyanurate groups were observed.

(Synthesis example of HDI modified “HDI-3”)
In a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, 988 g of HDI-1, 8 g of DMH, and 1.5 g of TOPIN were charged. This was heated to 50-60 ° C. with stirring, and the urethanization reaction was advanced until the target NCO content was reached. Then, the anti-uretdione conversion and isocyanuration reactions are advanced, and when the predetermined NCO content (NCO content at the time of stopping the reaction) is reached, the reaction is stopped by adding the terminator H as a stopper. A product solution was obtained. Unreacted HDI was removed by thin film distillation at 120 to 140 ° C. and 0.01 to 0.05 Torr, the isocyanate content was 22.3%, the viscosity at 25 ° C. was 90 mPa · s, and the free hexamethylene diisocyanate content was 0. A polyisocyanate “HDI-3” having a color content of 2%, a color number of 50 APHA, a uretdione dimer content of 56%, and an isocyanurate cyclic trimer content of 36% was obtained. The uretdione dimer content and the isocyanurate cyclic trimer content were determined from a calibration curve based on the area percentage of each peak obtained by gel permeation chromatography by differential refractometer detection.

(Preparation of polyol premix (1))
SV-165 70 parts (parts by mass; same applies hereinafter), DK3776 30 parts, TCPP 50 parts, SH193 1.5 parts, water 5 parts, DT 0.2 parts, DM70 0 .5 parts and 0.5 part of PC-41 were mixed and mixed and stirred to obtain a polyol premix. The resulting polyol premix had a viscosity at 25 ° C. of 320 mPa · s.
The obtained polyol premix was used in Examples 1-8 and Comparative Examples 1-8.

(Preparation of polyol premix (2))
70 parts of SV-165, 30 parts of DK3776, 50 parts of TCPP, 1.5 parts of SH193, 5 parts of water, 2 parts of DT, 5 parts of DM70, 5 parts of PC-41 By mixing and stirring, a polyol premix was obtained. The resulting polyol premix had a viscosity at 25 ° C. of 300 mPa · s.
The resulting polyol premix was used in Example 9.

(Production of rigid polyurethane foam: Examples 1 to 8, Comparative Examples 1 to 8)
The polyisocyanate blended under the conditions shown in Table 1 and the above polyol premix were adjusted to a temperature of 20 ° C., both were mixed equally by volume with a stirrer, and stirred and mixed at 3000 rpm for 4 seconds. After that, the obtained mixed liquid is poured onto a kraft paper set on a 0.35 mm-thick color steel plate adjusted to either 0 ° C. or 20 ° C. and foamed to obtain a rigid polyurethane foam. It was.
About the obtained rigid polyurethane foam, adhesiveness (adhesion strength, peel strength) and dimensional stability (volume shrinkage) were calculated | required by the measurement and evaluation method mentioned later. In the table, the temperature of the term “adhesive strength” corresponds to 0 ° C. or 20 ° C. which is the temperature of the color steel plate.
Table 1 summarizes the results of viscosity and adhesiveness and dimensional stability of the blended polyisocyanate in each Example and Comparative Example. The same applies to Example 9 below.

(Production of rigid polyurethane foam: Example 9)
Adjust the temperature of the polyisocyanate blended under the conditions shown in Table 1 and the above polyol premix to 20 ° C., mix them equally in a volume ratio with a spray foaming machine, and apply the following spraying conditions on the veneer plate as the adherend Airless spray foaming was performed to obtain a rigid polyurethane foam.
<Spray construction conditions>
○ Spray foaming machine: GUSMER FF-1600
○ Mixing head: D gun ○ Temperature of adherend: 0 ℃
○ Primary heater set temperature: 30 ~ 45 ℃
○ Hose heater set temperature: 30 ~ 45 ℃

(Raw ingredient list)
<Aromatic isocyanate>
○ MDI-1: MR-200 manufactured by Nippon Polyurethane Industry Co., Ltd. (Pure MDI content: 40 PA (peak area)%, NCO content: 30.8 mass%, viscosity at 25 ° C .: 190 mPa · s)
○ MDI-2: Millionate MT (NCO content: 33.6% by mass, viscosity at 43 ° C .: 5 mPa · s) manufactured by Nippon Polyurethane Industry Co., Ltd.
○ TDI-1: Millionate T-80 manufactured by Nippon Polyurethane Industry Co., Ltd. (NCO content: 48.3 mass%, viscosity at 23 ° C .: 3 mPa · s)
<Aliphatic isocyanate>
○ HDI-1 manufactured by Nippon Polyurethane Industry Co., Ltd. HDI (NCO content: 49.9% by mass, viscosity at 23 ° C .: 2 mPa · s)
○ HDI-4: Nippon Polyurethane Industry Co., Ltd. Coronate HX (NCO content 21.1 mass% HDI trimer content 99.0 mass% HDI monomer content 1% or less Viscosity at 25 ° C. 2600 mPa · s )
<Alicyclic isocyanate>
○ IPDI-1: manufactured by Mitsui Chemicals Polyurethane Industry Co., Ltd. (NCO content: 37.7% by mass, viscosity at 20 ° C .: 15 mPa · s)
<Polyol>
○ SV-165: Phthalic acid polyester polyol, manufactured by Hitachi Chemical Co., Ltd. (Hydroxyl value 200KOHmg / g)
○ DK3776: Mannich polyether polyol, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (hydroxyl value 350 KOHmg / g)
○ TCPP: Tris (chloropropyl) phosphate, manufactured by Akzo Nobel
<Foam stabilizer>
○ SH193: Made by Toray Dow Corning Silicone (silicone-based foam stabilizer)
<Catalyst>
○ DT: Toyocat DT manufactured by Tosoh Corporation
○ DM70: Toyocat DM70 manufactured by Tosoh Corporation
○ PC-41: San Cat Pro Polycat 41
<Auxiliary>
○ DMTG: Triethylene glycol dimethyl ether
○ DOM: Dioctyl maleate

(Method for evaluating foam characteristics)
(1) Measuring method of peel strength (adhesive strength) in adhesion test Set kraft paper (Taiko Craft 75g / m ² manufactured by Daiko Paper Co., Ltd.) as an adherent substrate on a 0.35mm thick color steel plate. And placed in a dryer set at a predetermined temperature. When the base material temperature reaches the set temperature, a prepared liquid prepared by mixing and stirring rigid polyurethane foam raw materials such as polyol and polyisocyanate under a predetermined condition is poured onto kraft paper, and the diameter is 200 mm. The foamed foam is formed so as to have a substantially frustoconical shape with a center height of 50 mm. Mixing the raw materials of rigid polyurethane foam, 1 hour after the start of stirring, take out the kraft paper to which the foamed foam is adhered, turn it upside down, and cut into a 7 cm square in the part of the kraft paper located at the center of the foamed foam. One end of the square notch of the kraft paper that is cut off from the surrounding kraft paper and adheres only to the foamed foam is clipped and lifted with a spring balance until the square kraft paper completely peels from the foamed foam. The maximum force (unit: N) is measured to obtain the peel strength (unit: N / 7 cm) at the predetermined temperature.
The predetermined temperature in the method for measuring the peel strength in the adhesion test, in other words, the adhesion temperature or the environmental temperature is set to 0 ° C. in consideration of the use of the foam in a cold region. However, the present invention is not limited to this, and may be any temperature, for example, 20 ° C.

(2) Dimensional stability evaluation test A foamed foam is formed on the kraft paper by the same method as the peel strength measurement method in the adhesion test, and at least 1 cm from the peripheral edge of the kraft paper 24 hours after the start of stirring. The foamed foam is cut out from the separated core portion into a size of 100 mm × 100 mm square (thickness 20 mm) to obtain a plate-shaped test piece. The test piece is placed in a constant temperature bath at a set temperature of 80 ° C., and the test piece is taken out of the constant temperature bath 48 hours after the constant temperature is reached, and the dimensions are measured. The volume shrinkage rate (volume-based dimensional change rate) is obtained from this size and the size of the test piece before being placed in the thermostat.

In addition, about the rigid polyurethane foam obtained in Examples 1-8 and Comparative Examples 1-8, although adhesiveness and dimensional stability were measured and evaluated by said each method, the rigid polyurethane obtained in Example 9 was used. For the form, the following method was used.
That is, a 12 mm thick veneer was used as the adherend, and in the adhesion test, a wrinkle board cover was affixed thereon as an adhesive substrate, and the rigid polyurethane foam raw material was sprayed so that the rigid polyurethane foam had a thickness of 30 mm. After spraying and curing at 0 ° C. for 1.5 hours, the rigid polyurethane foam was peeled off from the plywood together with the adhesive base material, and a 5 cm square cut was made in the base material, and then the adhesiveness was determined by the measurement method described above.
In the dimensional stability test, a rigid polyurethane foam raw material is directly sprayed onto a plywood board, cured at room temperature for one day or more, and then the rigid polyurethane foam is peeled off from the plywood board. It cut out into the dimension of 70 mm x 70 mm square (thickness 15mm), was set as the plate-shaped test piece, and the dimensional stability was calculated | required with the above-mentioned measuring method.

Claims (5)

In the polyisocyanate for producing a rigid polyurethane foam used for producing a rigid polyurethane foam by reacting with a polyol in the presence of a catalyst and a blowing agent,
Polyurethane for producing rigid polyurethane foam, characterized by comprising 85 to 99.7 parts by mass of polymeric diphenylmethane diisocyanate and 0.3 to 15 parts by mass of either one or both selected from aliphatic isocyanate and alicyclic isocyanate Isocyanates.   2. The polyisocyanate for producing a rigid polyurethane foam according to claim 1, wherein the foaming agent is water.   2. The rigid polyurethane according to claim 1, wherein one or both selected from the aliphatic isocyanate and the alicyclic isocyanate is one or both of hexamethylene diisocyanate and a modified product thereof. Polyisocyanate for foam production.   The polyisocyanate for producing a rigid polyurethane foam according to claim 1, wherein the polyisocyanate has a viscosity at 25 ° C of 200 mPa · s or less.   The method for producing a rigid polyurethane foam in which a polyol and a polyisocyanate are reacted in the presence of a catalyst and a foaming agent, wherein the polyisocyanate for producing a rigid polyurethane foam according to any one of claims 1 to 4 is used. Manufacturing method of rigid polyurethane foam.