JP4457305B2 - Manufacturing method of rigid polyurethane slab foam and heat insulating material for piping - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method for producing a rigid polyurethane slab foam and a heat insulating material for piping, and more specifically, a method for producing a rigid polyurethane slab foam that does not generate scorch inside, has low thermal conductivity, and is excellent in flame retardancy. In addition, the present invention relates to a heat insulating material for piping obtained by cutting hard polyurethane slab foam obtained by such a production method.

  The rigid polyurethane slab foam obtained by the present invention is not foamed and molded into a specific shape such as various panels, boards and refrigerators, nor is it foamed by spray application like on-site foaming. Hard slab foam produced by free-foaming the composition injected into the mold with the top surface open, or by free-foaming the composition continuously discharged to the continuous line with the top surface open Is.

Conventionally, chlorofluorocarbons and hydrofluorocarbons have been used as foaming agents for forming rigid polyurethane foams.
Therefore, due to the recent demand for de-fluorination, water-foamed rigid polyurethane foam using water as a foaming agent has attracted attention.

The composition for forming a rigid polyurethane foam by a water foaming formulation contains polyisocyanate, a polyol component, and water as a foaming agent.
Here, as the “polyisocyanate”, polymethylene polyphenyl polyisocyanate containing diphenylmethane diisocyanate is usually used.
Moreover, polyether polyol formed by adding ethylene oxide or propylene oxide to toluenediamine is used as part of the “polyol component” (for example, see Patent Documents 1 to 5).

However, in the case of producing a rigid polyurethane slab foam using a composition of a conventionally known water foaming formulation including the compositions disclosed in Patent Documents 1 to 5, scorch (burning) is formed inside the formed slab foam. There is a problem that occurs.
This is because in the formation of slab foam of water foaming prescription, the calorific value is large and it is difficult to dissipate the internal heat because of the thick shape (slab) (the internal heat storage amount is large) Etc. And the scorch which generate | occur | produced in the inside of a slab foam invites the external appearance defect of a final product obtained by cutting this, a strength defect, etc.
As described above, the internal scorch that is not particularly a problem with a thin mold foam is a serious problem in manufacturing a slab foam, and its solution is strongly desired.

Moreover, none of the rigid polyurethane foams produced by the compositions disclosed in Patent Documents 1 to 5 have a high heat conductivity and a sufficient heat insulating effect / heat retaining effect. Furthermore, flame retardancy and dimensional stability are not satisfactory.
Japanese Patent Laid-Open No. 5-186549 JP-A-6-228260 Japanese Patent Laid-Open No. 6-239956 Japanese Patent Laid-Open No. 7-10955 Japanese Patent Laid-Open No. 9-132631

The present invention has been made based on the above situation.
A first object of the present invention is to provide a method for producing a rigid polyurethane slab foam that does not generate scorch therein, has low thermal conductivity, and is excellent in flame retardancy.
The second object of the present invention is to provide a method for producing a rigid polyurethane slab foam having excellent dimensional stability.
The third object of the present invention is a heat insulating material obtained by cutting a rigid polyurethane slab foam, which has no poor appearance or poor strength due to scorch, has low thermal conductivity, flame retardancy and dimensions. It is providing the heat insulating material for piping excellent also in stability.

The production method of the present invention comprises [A] component (a1) consisting of diphenylmethane diisocyanate (hereinafter abbreviated as “MDI” ) , a polyether polyol having 2 to 4 functional groups and a hydroxyl value of 100 to 900 mgKOH / g. A modified MDI (A1) obtained by modification with a modifying agent (hereinafter also referred to as “specific modifying agent” ) comprising:
Obtained by mixing the component (a2) comprising polymethylene polyphenyl polyisocyanate (hereinafter abbreviated as “polymeric MDI”) ,
The content ratio of MDI in the total amount of the component (a1) and the component (a2) is 30 to 80% by mass,
A modified polyisocyanate having an NCO content of 25-28%;
[B] a polyol component containing a polyether polyol (B1) obtained by adding ethylene oxide and / or propylene oxide to toluenediamine in a proportion of 50% by mass or more;
[C] A foam-forming composition containing a foaming agent comprising water is reacted.

  In the production method of the present invention, the mass ratio ([EO]: [PO]) of ethylene oxide and propylene oxide added to toluenediamine to obtain the polyether polyol (B1) is 0-50: 100-50. It is preferable that

In addition, as the [B] component, a polyether polyol (B1) of 50 to 90% by mass and a polyoxyethylene compound obtained by adding ethylene oxide and / or propylene oxide to an initiator having 6 or more OH groups in the molecule. It is preferable to contain a polyol component containing 50 to 10% by mass of ether polyol (B2).
Furthermore, the initiator used to obtain the polyether polyol (B2) is preferably sucrose.

  The heat insulating material for piping of the present invention is obtained by further cutting a rigid polyurethane slab foam obtained by reacting the foam-forming composition.

According to the production method of the present invention, it is possible to produce a rigid polyurethane slab foam that does not generate scorch inside the slab, has low thermal conductivity, and is excellent in flame retardancy.
Moreover, the rigid polyurethane slab foam which was further excellent in dimensional stability is manufactured by making the said mass ratio ([EO]: [PO]) which concerns on a polyether polyol (B1) into 0-50: 100-50. be able to.
The heat insulating material for piping of the present invention does not have poor appearance or poor strength due to scorch, has low thermal conductivity, and is excellent in flame retardancy and dimensional stability.

Hereinafter, the present invention will be described in detail.
<Production method of the present invention>
The production method of the present invention comprises a [A] component comprising a modified polyisocyanate; a [B] component comprising a polyol component containing a toluenediamine-based polyether polyol (B1), and a water (foaming agent) [C]. It is characterized by reacting a foam-forming composition containing the components.

<[A] component>
The component [A] is a modified polyisocyanate obtained by modifying at least a part of the polymeric MDI (a) containing MDI (binuclear) with a specific modifying agent.
The MDI (binuclear body) constituting the polymeric MDI (a) includes isomers of 4,4′-MDI, 2,4′-MDI, and 2,2′-MDI, and occupies 4,4 in the MDI. The proportion of '-MDI is preferably 50% or more.

  The proportion of MDI (binuclear body) in the polymeric MDI (a) is 30 to 80% by mass, preferably 35 to 75% by mass.

When the ratio of MDI (binuclear body) is less than 30% by mass, the viscosity of the modified polyisocyanate obtained by the polymeric MDI becomes excessive, which adversely affects the miscibility with the [B] component.
On the other hand, when the ratio of MDI (binuclear body) exceeds 80% by mass, the strength of the composition containing the modified polyisocyanate obtained by the polymeric MDI is insufficient and the foam does not stand up normally. It may become impossible to form a rigid slab foam. Moreover, the hard slab foam formed by the composition exhibits brittleness and does not have sufficient strength. Furthermore, the storage stability of the polymeric MDI (a), particularly the liquid storage stability in a low-temperature atmosphere of 0 ° C. or lower, deteriorates (for example, precipitation of crystals).

The component [A] is obtained by modifying at least part of the polymeric MDI (a) with a specific modifying agent.
The specific modifier for modifying the polymeric MDI is a polyether polyol having 2 to 4 functional groups and a hydroxyl value of 100 to 900 mgKOH / g.

  A specific modifier consists of a “polyether polyol”. Modification with polyester polyol is not preferred because the resulting modified isocyanate becomes turbid, causing problems in storage stability such as occurrence of phase separation of liquid and precipitation of crystals after time.

The number of functional groups of the polyether polyol constituting the specific modifier is 2 to 4, preferably 2.
When a monofunctional polyether (monool) is used as a modifier of polymeric MDI (a), physical properties such as compressive strength and dimensional stability of the hard slab foam formed from the resulting composition Is unfavorable because it decreases.
On the other hand, when a polyether polyol having a functional group number of 5 or more is used as a modifier for polymeric MDI (a), the resulting modified isocyanate has an excessively high viscosity, causing problems such as poor mixing. Since it occurs, it is not preferable.

The polyether polyol constituting the specific modifier can be produced by adding a cyclic ether to a compound having 2 to 4 active hydrogens as an initiator. Examples of the “compound having 2 to 4 active hydrogens” used for the production of the polyether polyol include ethylene glycol, 1,2-propanediol (propylene glycol), 1,3-propanediol, and 2,2-dimethyl. -1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, trimethylene glycol, triethylene glycol, Short-chain diols such as tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, bisphenol A; short-chain triols such as glycerin, hexanetriol, and trimethylolpropane Pentaerythritol (tetramethylolmethane), such as short chain tetraols such as tetramethylol cyclohexane can be exemplified.
Examples of the “cyclic ether” used for the production of the polyether polyol include alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide.

The polyether polyol constituting the specific modifier has a hydroxyl value of 100 to 900 mgKOH / g, preferably 200 to 700 mgKOH / g.
When a polyether polyol having a hydroxyl value of less than 100 mgKOH / g is used as a modifier for polymeric MDI, physical properties such as compressive strength and dimensional stability of the hard slab foam formed by the resulting composition are reduced. It is not preferable.
On the other hand, when a polyether polyol having a hydroxyl value exceeding 900 mgKOH / g is used as a modifier for polymeric MDI, the viscosity of the resulting modified isocyanate becomes excessively high, resulting in problems such as poor mixing. Therefore, it is not preferable.

  The average molecular weight of the polyether polyol constituting the specific modifier is preferably 125 to 2500, and more preferably 160 to 1200.

  Examples of the modification method using a specific modifier include a method in which a specific modifier is added to pre-warmed polymeric MDI (a) and this system is stirred and mixed. The heating temperature at the time of stirring is, for example, 40 to 80 ° C.

As a method for preparing [A] component by modifying “part” of polymeric MDI (a), for example,
(A) Polymeric MDI (a) is divided into a part (a1) and a remaining part (a2),
(B) “Part of the polymeric MDI (a1)” is modified with a specific modifying agent to obtain “modified (polymeric) MDI (A1)”,
(C) A method in which “modified (polymeric) MDI (A1)” and “unmodified“ polymeric MDI remainder (a2) ”are mixed may be mentioned.

Here, the “part of polymeric MDI (a1)” to be modified and the “remaining part (a2) of polymeric MDI (a2)” to be added later do not have to have the same composition. Etc. may be different.
Alternatively, two types of polymeric MDIs having different nuclear distributions may be prepared, and one of them may be the component (a1) and the other may be the component (a2).
Here, from the viewpoint of suppressing an increase in the viscosity of the obtained component [A], it is preferable that the “part of polymeric MDI (a1)” to be subjected to the modification treatment consists only of MDI (binuclear).

In this case,
(A) The polymeric MDI (a) is divided into a part (a1) made of MDI and a remaining part (a2) made of the polymeric MDI (or (a1) component made of MDI and the polymeric MDI (a2) ) Prepare each ingredient)
(B) “Part of MDI (a1)” is modified with a specific denaturing agent to obtain “modified MDI (A1)”,
(C) [A] component is obtained by mixing “modified MDI (A1)” and “remainder (a2) of polymeric MDI”.
In this case, MDI (binuclear body) may be included in the “residue (a2) of polymeric MDI”.

  Even when the polymer MDI (a) is modified “all”, the “modified polyisocyanate” constituting the obtained component [A] includes an unmodified polymeric MDI molecule and a modified polymeric MDI molecule. And coexist. That is, the polyether polyol molecule constituting the specific modifier is not prepolymerized by bonding to all the molecules constituting the polymeric MDI (a).

For example, in the “modified polyisocyanate” modified with a polyether polyol represented by the formula: HO— (R ¹ O) _n —H (wherein R ¹ is an alkylene group),
An “unmodified polymeric MDI molecule” represented by the formula: R ² (NCO) _m (wherein R ² is a polymethylene polyphenyl structural unit and m is an integer of 2 or more);
There exists a “modified polymeric MDI molecule” of the formula: (OCN) _m-1 R ² NHCOO— (R ¹ O) _n-1 R ¹ O—CONHR ² (NCO) _m−1 .

  The NCO content of the modified polyisocyanate constituting the component [A] is usually 25 to 28%, preferably 26 to 28%. As a result, the amount of heat generation is reduced, the reaction at the time of foam formation is mild, and even the thick slab foam can reliably prevent the occurrence of scorch inside.

  When the NCO content of the modified polyisocyanate is less than 25%, the viscosity becomes excessive, which adversely affects the mixing property with the [B] component.

  On the other hand, when the NCO content of the modified polyisocyanate exceeds 28%, it is impossible to prevent the occurrence of internal scorch in the slab foam formed by the composition obtained (Comparative Examples 1-2 and Comparative Examples described later) See Examples 5-6).

<[B] component>
[B] component which comprises a foam-forming composition consists of a polyol component which contains the polyether polyol (B1) which makes toluenediamine an initiator in the ratio of 50 mass% or more.

  The polyether polyol (B1) can be obtained by adding toluene oxide as an initiator and adding ethylene oxide and / or propylene oxide thereto.

  With the [B] component containing the toluenediamine-based polyether polyol (B1) in a certain ratio, it is possible to achieve finer cells in the formed hard slab foam, and low thermal conductivity (heat insulation and heat retention). Sex) can be achieved. Moreover, the flame retardance which was excellent in the hard slab foam formed can be provided. Furthermore, the [B] component containing the polyether polyol (B1) is also excellent in compatibility with the [A] component.

  As toluenediamine, 2,4-toluenediamine and 2,6-toluenediamine can be used alone or a mixture of both.

  Here, the mass ratio ([EO]: [PO]) of ethylene oxide and propylene oxide added with toluenediamine is preferably 0-50: 100-50, more preferably 0-35: 100-65. It is said. Thereby, the dimensional stability of the hard slab foam obtained can be improved.

The hydroxyl value of the polyether polyol (B1) is preferably 200 to 700 mgKOH / g, more preferably 300 to 500 mgKOH / g.
The average molecular weight of the polyether polyol (B1) is preferably 320 to 1200, and more preferably 450 to 750.

[B] The proportion of the polyether polyol (B1) in the component is 50% by mass or more, preferably 50 to 90% by mass.
When the proportion of the polyether polyol (B1) is less than 50% by mass, the heat conductivity of the hard slab foam to be formed becomes high, and good heat insulation and heat retention cannot be exhibited. The foam is inferior in flame retardancy (see Comparative Examples 3 to 4 and Comparative Example 6 described later).

Component [B] contains polyether polyol (B2) and polyether polyol (B2) formed by adding ethylene oxide and / or propylene oxide to an initiator having 6 or more OH groups in the molecule. Preferably it is.
According to the [B] component containing the polyfunctional polyether polyol (B2) at a certain ratio, the dimensional stability of the hard slab foam to be formed can be improved.

  Examples of the initiator for obtaining the polyether polyol (B2) include sucrose, sorbitol (glucitol), mannitol, dulcitol (galactitol), sucrose, etc. Among them, sucrose is preferable.

The hydroxyl value of the polyether polyol (B2) is preferably 300 to 600 mgKOH / g, more preferably 350 to 550 mgKOH / g.
The average molecular weight of the polyether polyol (B2) is preferably 550 to 1500, and more preferably 600 to 1300.

[B] The proportion of the polyether polyol (B2) in the component is preferably 10 to 50% by mass, more preferably 10 to 30% by mass.
When the ratio of the polyfunctional polyether polyol (B2) is less than 10% by mass, the formed hard slab foam is inferior in dimensional stability. On the other hand, when the proportion of the polyether polyol (B2) exceeds 50% by mass, the proportion of the toluenediamine-based polyether polyol (B1) cannot be 50% by mass or more.

[B] The component is preferably composed of a toluenediamine-based polyether polyol (B1) and a polyfunctional polyether polyol (B2), but within the range not impairing the effects of the present invention, A polyol may be contained.
Such polyols include polyether polyols [excluding those corresponding to the above (B1) and (B2). ], Polyester polyols, polycarbonate polyols, polyolefin polyols, animal and plant polyols, low molecular weight polyols having a molecular weight of 300 or less, polymer polyols, halogen-containing polyols, phosphorus-containing polyols, phenol-based polyols and the like that function as chain extenders. . Of these, polyether polyols are preferred.

<[C] component>
The foam-forming composition used in the present invention is a water-foaming composition containing water ([C] component) as a foaming agent.
As content of the water which is [C] component, it is preferable that it is 2-10 mass parts with respect to 100 mass parts of [B] component, More preferably, it is 3-7 mass parts. If this content is excessive, the density of the hard slab foam formed will be lower (lighter) than the desired density, leading to insufficient strength and reduced dimensional stability, The hard slab foam becomes brittle. On the other hand, when this content is too small, foaming becomes insufficient and the density increases, resulting in an increase in cost.

<Optional component>
The foam-forming composition used in the present invention may contain components other than the essential components as long as the effects of the present invention are not impaired.
Examples of such optional components include flame retardants, foam stabilizers, antioxidants, catalysts, fillers, stabilizers, colorants, and the like.

  “Flame retardants” that can be used as optional components include organic halogen compounds, phosphorus compounds, (iso) cyanuric acid derivative compounds (halogen-free nitrogen-containing compounds), and nitrogen-containing compounds other than (iso) cyanuric acid derivative compounds ( Non-halogen-containing nitrogen-containing compounds) and inorganic compounds.

  Here, as the “organic halogen compound”, tetrabromobisphenol A (TBBA), dibromoneopentyl glycol, decabromodiphenyl oxide (DBDPO), hexabromocyclododecane (HBCD), tribromophenol (TBP), ethylene bis Examples thereof include tetrabromophthalimide, brominated polystyrene, TBBPA epoxy oligomer, TBBPA bisdibromopropyl ether, and ethylene bispentabromodiphenyl.

  In addition, as the “phosphorus compound”, ammonium polyphosphate compound such as condensation product of ammonium orthophosphate and urea, trimethyl phosphate (TMP), triethyl phosphate (TEP), tributyl phosphate, trioctyl phosphate, triphenyl phosphate, Phosphate esters such as tricresyl phosphate and octyl diphenyl phosphate, condensed phosphate esters such as high molecular weight polyphosphate, tris (chloropropyl) phosphate (TCPP), tris (dichloropropyl) phosphate, tris (dibromoneo Examples thereof include halogen-containing phosphate esters such as pentyl phosphate.

  In addition, as “(iso) cyanuric acid derivative compound (non-halogen-containing nitrogen-containing compound)”, melamine, melamine sulfate, melamine phosphate, melamine polyphosphate, methylol melamine, cyanuric acid trimethyl ester, cyanuric acid triethyl ester, ammelin, Examples thereof include cyanuric acid derivatives such as ammelide, 2,4,6-trioxycyanidine, and melamine cyanurate; isocyanuric acid derivatives such as isoammelin, isomelamine, isoammelide, trimethylcarbodiimide, triethylcarbodiimide, and tricarbimide.

  In addition, “nitrogen-containing compounds other than (iso) cyanuric acid derivative compounds (halogen-free nitrogen-containing compounds)” include cyanamide derivatives such as dicyandiamide, dicyandiamidine, guanidine, guanidine sulfamate, and diguanide; and urea, Examples thereof include urea derivatives such as dimethylolurea, diacetylurea, trimethylurea, and N-benzoylurea.

  “Inorganic compounds” include magnesium hydroxide, aluminum hydroxide, sodium tetraborate, magnesium phosphate, sodium diphosphate, zinc phosphate, antimony trioxide, antimony pentoxide, nitrogenated guanidine, red phosphorus Etc. can be illustrated.

  Examples of the “foam stabilizer” used as an optional component include “SZ-1171”, “SZ-1649”, “SZ-1666”, “SZ-1694”, “SZ-1671”, “SZ-1711”. ”,“ SZ-1127 ”,“ SZ-1919 ”(manufactured by Nihon Unicar Co., Ltd.),“ SF-2936F ”,“ SF-2937F ”,“ SF-2938F ”,“ SH-192 ”(above, Toray Dow Corning Silicone Co., Ltd.), “B-8444”, “B-8465”, “B-8870”, “B-8871” (above, manufactured by Goldschmidt), “F-373”, “F-388” (manufactured by Shin-Etsu Chemical Co., Ltd.) can be used.

  Examples of the “antioxidant” that can be used as an optional component include phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants.

  Here, as the “phenolic antioxidant”, pentaerythrityl-tetrakis- [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 3,9-bis {2 -[3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxapyro [5,5] undecane, 1,3,5-tris (2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) ) -2,4,6-trimethylbenzene, 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, bis (3,5-di-t-butyl-4) -Hydro (Ethyl benzyl phosphonate) calcium, 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5 -Di-t-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol), 4,4'-thiobis (3-methyl-6-tert-butylphenol), 4,4'-butylidenebis (3-methyl-6-tert-butylphenol), 3,9-bis [1,1-dimethyl-2- [Β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] 2,4,8,10-tetraoxaspiro [5.5] un Can, 1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl) -4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis- (4 ′ -Hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, 1,3,5-tris (3 ', 5'-di-t-butyl-4'-hydroxybenzyl) -S-triazine-2 , 4,6- (1H, 3H, 5H) trione, tocopherols and the like.

  In addition, examples of the “phosphorus antioxidant” include phosphorus stabilizers such as alkyl phosphites, alkyl allyl phosphites, allyl phosphites, alkyl phosphonites, and allyl phosphonites. Specifically, Bis (tridecyl) pentaerythritol diphosphite, tris (2,4-di-t-butylphenyl) phosphite, distearylpentaerythritol diphosphite, tetrakis (2,4-di-t-butylphenyl) -4 , 4'-biphenylenephosphonite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite 1,1,3-tris (2-methyl-4-ditridecyl phosphite-5- -Butylphenyl) butane, triphenylphosphite, diphenylisodecylphosphite, 4,4'-butylidene-bis (3-methyl-6-tert-butylphenylditridecyl) phosphite, cyclic neopentanetetraylbis ( Octadecylphosphite), tris (nonylphenyl) phosphite, tris (monononylphenyl) phosphite, tris (dinonylphenyl) phosphite, diisodecylpentaerythritol diphosphite, 9,10-dihydro-9-oxa-10- Phosphaphenanthrene-10-oxide, 10- (3,5-di-tert-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy -9,10-jihi Ro-9-oxa-10-phosphaphenanthrene, tris (2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,4-di-t-butylphenyl) phosphite, Examples include cyclic neopentanetetraylbis (2,6-di-t-butyl-4-methylphenyl) phosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite be able to.

  Examples of the “sulfur antioxidant” include distearyl-3,3′-thiodipropionate, pentaerythritol-tetrakis (3-laurylthiopropionate), dilauryl-3,3′-thiodipropioate. Nate, dimyristyl-3,3'-thiodipropionate, ditridecyl-3,3'-thiodipropionate, dilauryl thiodipropionate, and the like.

Examples of the “catalyst” that can be used as an optional component include triethylenediamine (TEDA), tetramethylhexamethylenediamine (TMHMDA), pentamethyldiethylenetriamine (PMDETA), dimethylcyclohexylamine (DMCHA), bisdimethylaminoethyl ether (BDMAEA), N -Amine compounds such as methylimidazole, trimethylaminoethylpiperazine, tripropylamine, triethylamine, N-methylmorpholine, tin compounds such as dibutyltin diacetate and dibutyltin dilaurate, metal complex compounds such as acetylacetone metal salts, reactive amine catalysts [ For example, dimethylethanolamine (DMEA), N, N, N′-trimethylaminoethylethanolamine, N, N-dimethylaminoethoxye The urethanization catalyst represented by [Tanol] can be mentioned.
As content of a catalyst, it is preferable that it is 0-2.5 mass parts with respect to 100 mass parts of [B] component, More preferably, it is 0-1.0 mass part.

<Manufacturing method>
The production method of the present invention is a method for producing a rigid slab foam by reacting a foam-forming composition.
The foam-forming composition is, for example, a two-component curable composition composed of a first liquid composed of the [A] component and a second liquid obtained by mixing the [B] component, the [C] component and an optional component. Used as a composition.
The foam-forming composition is also composed of three liquids composed of a first liquid composed of the component [A], a second liquid composed of the component [B], and a third liquid composed of the component [C] and an optional component. It may be used as a curable composition.

A specific manufacturing method is not particularly limited, and a conventionally known method for manufacturing a hard slab foam can be employed.
If an example of a manufacturing method is shown here, 1st liquid ([A] component) and 2nd liquid ([B] component, the polyol mixture containing a [C] component and an arbitrary component) will be well-known stirring mixing. A foam-forming composition (foamable mixture) is prepared by mixing with a machine, and this is injected into a mold with the top surface open to allow free foaming, followed by curing and molding as a slab (block) (discontinuous) Law).
As another example of the production method, the first liquid ([A] component) and the second liquid ([B] component, [C] component and polyol mixture containing the optional component) are mixed with a known stirring mixer. To form a foam-forming composition (foamable mixture), which is continuously discharged into a continuous line with the top surface open to allow free foaming, followed by curing and molding as a slab (continuous method). be able to.
The rigid slab foam produced by the production method of the present invention has a closed cell structure, specifically, a closed cell ratio measured in accordance with ASTM D2856 exceeds 75%.

<Insulation for piping>
FIG. 1 is a perspective view showing an example of a heat insulating material for piping according to the present invention, and FIG. 2 is an explanatory view showing a state where the heat insulating material shown in FIG.
The heat insulating materials 1A and 1B shown in FIG. 1 have a shape formed by dividing (halving) a cylindrical body in the vertical direction. The heat insulating materials 1A and 1B are formed by cutting a hard slab foam formed by the manufacturing method of the present invention. Note that “cutting” includes “cutting” and the like.
As shown in FIG. 2, the heat insulating materials 1 </ b> A and 1 </ b> B are arranged so as to cover the surface of the pipe P and are fixed by the tying means 3 in that state.
The outer surfaces of the heat insulating materials 1A and 1B may be covered with a gas-impermeable sheet or film. This prevents the gas (carbon dioxide) in the bubbles constituting the foam from being replaced with air (having a higher thermal conductivity than carbon dioxide), so that the initial heat insulation can be maintained. As such a “gas-impermeable sheet or film”, a laminate film having an aluminum layer as one layer can be exemplified.

  Since the heat insulating materials 1A and 1B are formed from a hard slab foam formed from the foam-forming composition, there is no appearance defect or strength defect due to the scorch inside the slab. In addition, it has low thermal conductivity and excellent heat insulation and heat retention, and also has excellent flame retardancy and dimensional stability.

  In addition, the shape of the heat insulating material for piping of this invention and the mounting method to piping are not limited to said thing.

Examples of the present invention will be described below, but the present invention is not limited thereto.
In the following, “%” and “part” mean “% by mass” and “part by mass”, respectively, unless otherwise specified.

[Preparation Example 1]
In a reaction vessel equipped with a stirrer, a thermometer, a cooler, and a nitrogen introduction tube, a dinuclear body containing MDI (a1) (4,4′-MDI at a ratio of 70% or more according to the formulation shown in Table 1 below. ) 48 parts were charged and heated to 60 ° C., and then 8 parts of a specific modifier (d1) composed of polyoxypropylene glycol having an average molecular weight of 200 and a hydroxyl value of 561 mg KOH / g was added. The MDI was denatured by stirring for about 2 hours.
Next, 44 parts of polymeric MDI (a2) was added to and mixed with the reaction product [modified MDI], whereby an [A] component consisting of a modified polyisocyanate having an NCO content of 26.0% (hereinafter referred to as “[A -1] component ") 100 parts were obtained.

The viscosity (25 ° C.) of the component [A-1] was 500 mPa · s, and the ratio of the dinuclear body (unmodified MDI molecule) contained in the component [A-1] was 44%.
Moreover, the ratio of the binuclear body in the total amount (92 parts) of MDI (a1) subjected to the modification treatment and the polymeric MDI (a2) mixed after the modification is 71.3%.

[Preparation Example 2]
According to the formulation shown in Table 1 below, the amount of MDI (a1) charged was changed to 37 parts; a specific modifier (d1) 3.4 comprising polyoxypropylene glycol having an average molecular weight of 200 and a hydroxyl value of 561 mg KOH / g. Part and 4.6 parts of a specific modifier (d2) made of polyoxypropylene glycol having an average molecular weight of 400 and a hydroxyl value of 281 mgKOH / g to modify MDI; addition of polymeric MDI (a2) 100 parts of [A] component (henceforth "[A-2] component") which consists of modified polyisocyanate whose NCO content is 27.0% like preparation example 1 except having changed the quantity into 55 parts. Got.

The viscosity (25 ° C.) of the component [A-2] was 300 mPa · s, and the content ratio of the dinuclear body (unmodified MDI molecule) in the component [A-2] was 44%.
The ratio of the binuclear body in the total amount (92 parts) of the MDI (a1) subjected to the modification treatment and the polymeric MDI (a2) mixed after the modification is 64.1%.

[Preparation Example 3]
According to the formulation shown in Table 1 below, the amount of MDI (a1) charged was changed to 37 parts; trifunctional polyether polyol obtained by adding propylene oxide to glycerin (average molecular weight = 600, hydroxyl value = 281 mgKOH / g) The MCO was modified by adding 8 parts of a specific modifying agent (d3) consisting of: The NCO content was 27 as in Preparation Example 1 except that the amount of polymeric MDI (a2) added was changed to 55 parts. 100 parts of [A] component (hereinafter referred to as “[A-3] component”) composed of 0.0% modified polyisocyanate was obtained.
The viscosity (25 ° C.) of the component [A-3] was 330 mPa · s, and the content ratio of the dinuclear body (unmodified MDI molecule) in the component [A-3] was 49%.
The ratio of the binuclear body in the total amount (92 parts) of the MDI (a1) subjected to the modification treatment and the polymeric MDI (a2) mixed after the modification is 64.1%.

[Preparation Example 4]
According to the formulation shown in Table 1 below, the amount of MDI (a1) charged was changed to 37 parts; a tetrafunctional polyether polyol obtained by adding propylene oxide to pentaerythritol (average molecular weight = 561, hydroxyl value = 400 mgKOH / The NCO content was the same as in Preparation Example 1 except that 8 parts of the specific modifier (d4) consisting of g) was added to modify the MDI; the amount of polymeric MDI (a2) added was changed to 55 parts 100 parts of [A] component (henceforth "[A-4] component") which consists of 27.0% of modified polyisocyanate.
The viscosity (25 ° C.) of the component [A-4] was 580 mPa · s, and the content ratio of the dinuclear body (unmodified MDI molecule) in the component [A-4] was 44%.
The ratio of the binuclear body in the total amount (92 parts) of the MDI (a1) subjected to the modification treatment and the polymeric MDI (a2) mixed after the modification is 64.1%.

[Preparation Example 5]
In accordance with the formulation shown in Table 1 below, the amount of MDI (a1) charged was changed to 51 parts; trifunctional polyether polyol obtained by adding propylene oxide to glycerin (average molecular weight = 250, hydroxyl value = 673 mgKOH / g) [A] component consisting of a modified polyisocyanate having an NCO content of 28.0% (hereinafter referred to as “A” component), except that 5 parts of a specific modifier (d5) consisting of 100 parts of “[A-5] component”.
The viscosity (25 ° C.) of the component [A-5] was 280 mPa · s, and the content ratio of the binuclear body (unmodified MDI molecule) in the component [A-5] was 52%.
Moreover, the ratio of the binuclear body in the total amount (95 parts) of MDI (a1) subjected to the modification treatment and polymeric MDI (a2) mixed after the modification is 72.2%.

[Preparation Example 6]
In accordance with the formulation shown in Table 1 below, the amount of MDI (a1) charged was changed to 32 parts; the amount of specific modifier (d1) added was changed to 4 parts, and MDI was modified; Polymeric MDI (a2) 100 parts of modified polyisocyanate having an NCO content of 29.0% was obtained in the same manner as in Preparation Example 1, except that the addition amount of was changed to 64 parts.
The viscosity (25 ° C.) of this modified polyisocyanate was 180 mPa · s, and the content ratio of the dinuclear body (unmodified MDI molecule) in the modified polyisocyanate was 48%.
The ratio of the binuclear body in the total amount (96 parts) of the MDI (a1) subjected to the modification treatment and the polymeric MDI (a2) mixed after the modification is 60.0%.

[Preparation Example 7]
Polymeric MDI (a2) used in Preparation Examples 1 to 6 (dinuclear body = 40%, trinuclear body = 27%, tetranuclear body = 9%, pentanuclear body or hexanuclear body = 5%, heminuclear body or more Of polynuclear body = 19%: NCO content = 31.0%).

* 1): MDI (binuclear) containing 4,4'-MDI in a proportion of 70% or more
* 2): Polyoxypropylene glycol (number of functional groups = 2, average molecular weight = 200, hydroxyl value = 561 mgKOH / g)
* 3): Polyoxypropylene glycol (number of functional groups = 2, average molecular weight = 400, hydroxyl value = 281 mgKOH / g)
* 4): Polyether polyol formed by adding propylene oxide to glycerin (number of functional groups = 3, average molecular weight = 600, hydroxyl value = 281 mgKOH / g)
* 5): Polyether polyol formed by adding propylene oxide to pentaerythritol (number of functional groups = 4, average molecular weight = 561, hydroxyl value = 400 mgKOH / g)
* 6): Polyether polyol formed by adding propylene oxide to glycerin (number of functional groups = 3, average molecular weight = 250, hydroxyl value = 673 mgKOH / g)
* 7): Polymeric MDI for post-addition (binuclear body = 40%, trinuclear body = 27%, tetranuclear body = 9%, pentanuclear body or hexanuclear body = 5%, polynuclear body more than heptanuclear body = 19%: NCO content = 31.0%)

<Example 1>
According to the formulation shown in Table 2 below, 131.7 parts of a polyol mixture (liquid temperature = 30 ° C.) containing [B] component, [C] component and optional components, and [A-1] obtained in Preparation Example 1 183.0 parts (NCO index = 100) of components (liquid temperature = 20 ° C.) were mixed and discharged using a high-pressure foaming machine to prepare a foamable composition.
The mass ratio ([EO]: [PO]) of ethylene oxide and propylene oxide constituting the polyether polyol (B1) used in this example is 34:66.
The composition discharged from the low pressure foaming machine was poured into a wooden mold with an open top surface having internal dimensions of 600 mm × 600 mm × 600 mm, and the reaction time (cream time and rise time) in the foaming / curing molding process was measured. The results are also shown in Table 2.
A demolding operation was performed after 1 hour from the start time of the stirring and mixing operation to obtain a rigid polyurethane slab foam.

<Examples 2 to 9>
According to the formulation shown in Table 2 below, the blend ratio (amount) shown in Table 2 is such that the polyol mixture containing the [B] component, the [C] component and the optional component, and the [A] component have an NCO index of 100. In the same manner as in Example 1 except that it was used in the above), the stirring and mixing operation (preparation of foamable composition) of the polyol mixture and the component [A], the injection operation of the composition, the measurement of the reaction time (results were Each of the rigid polyurethane slab foams was obtained by performing the demolding operation shown in Table 2 below.
The mass ratio ([EO]: [PO]) of ethylene oxide and propylene oxide constituting the polyether polyol (B1) used in these examples is
In Examples 2 to 5, [EO]: [PO] = 34: 66,
In Example 6, [EO]: [PO] = 49: 51,
In Examples 7 to 8, [EO]: [PO] = 20: 80,
In Example 9, [EO]: [PO] = 63: 37.

[Notes on Table 2 (same in 3 below)]
* 8) (B1-1): A polyether polyol obtained by adding EO and PO to toluenediamine. Number of functional groups = 4, average molecular weight = 561, hydroxyl value = 400 mgKOH / g, viscosity (25 ° C.) = 20,000 mPa · s, [EO]: [PO] = 20: 80 (mass ratio). * 9) (B1-2): A polyether polyol obtained by adding EO and PO to toluenediamine. Functional group number = 4, average molecular weight = 748, hydroxyl value = 300 mgKOH / g, viscosity (25 ° C.) = 2,000 mPa · s, [EO]: [PO] = 70: 30 (mass ratio).
* 10) (B2-1): Polyether polyol formed by adding PO to sucrose. Number of functional groups = 8, average molecular weight = 1069, hydroxyl value = 420 mgKOH / g, viscosity (25 ° C.) = 28,000 mPa · s.
* 11) (b-1): A polyether polyol obtained by adding PO to glycerin. Number of functional groups = 3, average molecular weight = 599, hydroxyl value = 281 mgKOH / g, viscosity (25 ° C.) = 270 mPa · s.
* 12) (b-2): Polyether polyol formed by adding PO to monoethanolamine. Number of functional groups = 3, average molecular weight = 337, hydroxyl value = 500 mg KOH / g, viscosity (25 ° C.) = 430 mPa · s.
* 13) Flame retardant (TCPP): Tris (chloropropyl) phosphate * 14) Foam stabilizer (1): “B-8465” (manufactured by Goldschmidt)
* 15) Foam stabilizer (2): “SZ-1671” (Nippon Unicar Co., Ltd.)
* 16) Catalyst (1): “Kaoriza No. 1” (manufactured by Kao Corporation)
* 17) Antioxidant (1): Tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane “Irganox 1010” (Ciba Specialty Chemicals) (Made by Co., Ltd.)
* 18) Antioxidant (2): Bis (tridecyl) pentaerythritol diphosphite “JPP-13R” (manufactured by Johoku Chemical Co., Ltd.)

<Comparative Example 1>
Example 1 except that 164.0 parts of the modified polyisocyanate (NCO content = 29.0%) obtained in Preparation Example 6 was used instead of the component [A-1] according to the formulation shown in Table 3 below. In the same manner, the stirring and mixing operation (preparation of foamable composition) of the polyol mixture and the modified polyisocyanate, the injection operation of the composition, the measurement of the reaction time (results are shown in Table 3 below) and the demolding operation are performed. A rigid polyurethane slab foam was obtained.
This example is a comparative example in which the NCO content of the modified polyisocyanate exceeds 28%.

<Comparative example 2>
In accordance with the prescription shown in Table 3 below, in place of [A-1] component, Examples were used except that 153.0 parts of polymeric MDI (a2) (NCO content = 31.0%) prepared in Preparation Example 7 was used. 1, the stirring and mixing operation (preparation of foamable composition) of the polyol mixture and polymeric MDI, the injection operation of the composition, the measurement of the reaction time (results are shown in Table 3 below) and the demolding operation A rigid polyurethane slab foam was obtained.
This example is a comparative example using unmodified polymeric MDI (NCO content = 31.0%).

<Comparative Example 3>
According to the formulation shown in Table 3 below, 131.2 parts of a polyol mixture containing a polyol component, a [C] component and an optional component, and 173.0 parts of the [A-2] component obtained in Preparation Example 2 (NCO index = 100) in the same manner as in Example 1 except that the polyol mixture and [A-2] component were stirred and mixed (preparation of foamable composition), the composition injection operation, and the reaction time. Measurement (results are shown in Table 3 below) and demolding operation were performed to obtain a rigid polyurethane slab foam.
This example is a comparative example using a polyol component in which the proportion of the toluenediamine-based polyether polyol (B1) is less than 50% by mass.

<Comparative example 4>
According to the formulation shown in Table 3 below, 131.8 parts of a polyol mixture containing a polyol component, a [C] component and an optional component, and 197.0 parts of the [A-2] component obtained in Preparation Example 2 (NCO index = 100) in the same manner as in Example 1 except that the polyol mixture and [A-2] component were stirred and mixed (preparation of foamable composition), the composition injection operation, and the reaction time. Measurement (results are shown in Table 3 below) and demolding operation were performed to obtain a rigid polyurethane slab foam.
This example is a comparative example using a polyol component not containing a toluenediamine-based polyether polyol (B1).

<Comparative Example 5>
In accordance with the formulation shown in Table 3 below, 131.2 parts of a polyol mixture containing the [B] component, the [C] component and an optional component, and the polymeric MDI (a2) prepared in Preparation Example 7 (NCO content = 31.0%) ) Stir mixing operation (preparation of foamable composition) of polyol mixture and polymeric MDI, injection of composition in the same manner as in Example 1 except that 150.0 parts (NCO index = 100) were used. Operation, measurement of reaction time (results are shown in Table 3 below) and demolding operation were performed to obtain a rigid polyurethane slab foam.
This example is a comparative example using unmodified polymeric MDI (NCO content = 31.0%).

<Comparative Example 6>
In accordance with the formulation shown in Table 3 below, 131.8 parts of a polyol mixture containing a polyol component, a [C] component and an optional component, and polymeric MDI (a2) prepared in Preparation Example 7 (NCO content = 31.0%) 173 0.0 part (NCO index = 100) was used in the same manner as in Example 1, except that the polyol mixture and polymeric MDI were stirred and mixed (preparation of foamable composition), the composition injection operation, The reaction time was measured (results are shown in Table 3 below) and demolding operation was performed to obtain a rigid polyurethane slab foam.
This example is a comparative example using a polyol component not containing a toluenediamine-based polyether polyol (B1) and using unmodified polymeric MDI (NCO content = 31.0%).

* 19) (b-3): A polyether polyol obtained by adding PO to glycerin. Number of functional groups = 3, average molecular weight = 250, hydroxyl value = 673 mgKOH / g, viscosity (25 ° C.) = 950 mPa · s.
* 20) Catalyst (2): “Toyocat DT” (manufactured by Tosoh Corporation)

<Evaluation of slab form>
Each of the rigid polyurethane slab foams (600 mm × 600 mm × 600 mm) obtained in Examples 1 to 9 and Comparative Examples 1 to 6 was demolded and allowed to stand at room temperature for 24 hours, and then the following (1) to The item (6) was measured and evaluated. For the slab foams according to Comparative Example 2, Comparative Example 5 and Comparative Example 6 where the evaluation of the following (3) is “x”, the following measurements (5) and (6) were not performed. The results are shown in Table 4 below.

(1) Density:
In accordance with JIS K7222, the size and mass of the test piece (200 mm × 200 mm × 200 mm) cut out from the slab foam were measured to determine the density (kg / m ³ ).

(2) Closed cell ratio:
Using a test piece [30 mm × 30 mm × 130 mm (foaming direction)] cut out from the slab foam, the closed cell ratio (%) was measured in accordance with ASTM D2856.

(3) Presence of internal scorch:
The slab foam was cut and the inside was observed, and the occurrence of scorch was evaluated based on the following criteria.
・ "O": No scorch is observed.
-"△": Scorch is slightly generated (the center of the foam is slightly browned).
-"X": Scorch generation is clearly observed (the center of the foam has turned brown).

(4) Thermal conductivity:
A slab foam is cut (sliced) parallel to the foaming direction to produce a test piece of 200 mm (foaming direction) × 200 mm × 25 mm, and a thermal conductivity measuring device (auto Λ) is used according to JIS A 1412. Measured.
As a heat insulating material made of rigid polyurethane foam, the thermal conductivity is required to be 0.024 W / mK or less.

(5) Combustion test:
In accordance with JIS A 9511, the combustion distance and the combustion time were measured, and the combustibility was evaluated based on these.

(6) Dimensional stability (measurement of volume change rate):
Dimensional stability was evaluated by measuring the volume change when a test piece (50 mm × 50 mm × 50 mm) cut out from the slab foam was allowed to stand in the following atmosphere for a fixed time.
・ 80 ℃ × 2 days ・ −20 ℃ × 2 days

  The rigid polyurethane slab foam obtained by the production method of the present invention is suitably used as a raw material for producing products (particularly, heat insulation materials for various pipes) used for various applications that require heat insulation and heat insulation. Used.

It is a perspective view which shows an example of the heat insulating material for piping of this invention. FIG. 2 is an explanatory diagram illustrating a state in which the heat insulating material illustrated in FIG.

Explanation of symbols

1A Insulation 1B Insulation 3 Tightening means

Claims (5)

[A] Modified diphenylmethane diisocyanate (A1) obtained by modifying component (a1) composed of diphenylmethane diisocyanate with a modifying agent composed of a polyether polyol having 2 to 4 functional groups and a hydroxyl value of 100 to 900 mgKOH / g ) And (a2) component consisting of polymethylene polyphenyl polyisocyanate ,
The content ratio of diphenylmethane diisocyanate in the total amount of the component (a1) and the component (a2) is 30 to 80% by mass,
A modified polyisocyanate having an NCO content of 25-28%;
[B] a polyol component containing a polyether polyol (B1) obtained by adding ethylene oxide and / or propylene oxide to toluenediamine in a proportion of 50% by mass or more;
[C] A method for producing a rigid polyurethane slab foam, in which a foam-forming composition containing a foaming agent comprising water is reacted.   The mass ratio ([EO]: [PO]) of ethylene oxide and propylene oxide added to toluenediamine to obtain the polyether polyol (B1) is 0-50: 100-50. Manufacturing method of rigid polyurethane slab foam. As said [B] component,
Polyether polyol (B2) 50 to 90% by mass, and polyether polyol (B2) 50 to 10% by adding ethylene oxide and / or propylene oxide to an initiator having 6 or more OH groups in the molecule The manufacturing method of the rigid polyurethane slab foam of Claim 1 or Claim 2 containing the polyol component containing%.   The manufacturing method of the rigid polyurethane slab foam of Claim 3 whose initiator used in order to obtain the said polyether polyol (B2) is sucrose.   A heat insulating material for piping obtained by cutting a rigid polyurethane slab foam obtained by the production method according to any one of claims 1 to 4.

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