JP2008133317A - Polyol composition for rigid polyurethane foam and method for producing rigid polyurethane foam - Google Patents

Abstract

A polyol composition for rigid polyurethane foam, which uses a polyether polyol having water as a foaming agent and does not have a hydrolysis problem, and satisfies the JIS A 9511 standard of flame resistance, and the polyol composition. A method for producing a rigid polyurethane foam used is provided.
A polyol composition comprising a polyol compound, a foaming agent, a catalyst and a foam stabilizer, and reacting with a polyisocyanate component to form a rigid polyurethane foam, wherein the foaming agent is water and the polyol compound is a hydroxyl group. A polyol composition which is an aliphatic polyether polyol having an initiator of pentaerythritol having a value of 350 to 550 mgKOH / g. The method for producing a rigid polyurethane foam uses the polyol composition.
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Description

  The present invention relates to a polyol composition for a rigid polyurethane foam having foamed water and a method for producing a rigid polyurethane foam using the polyol composition.

  Rigid polyurethane foam is a well-known material as a heat insulating material, a lightweight structural material, and the like. Such a rigid polyurethane foam is formed by mixing a polyol composition containing a polyol compound and a foaming agent as essential components and a polyisocyanate component, and foaming and curing. In the past, chlorofluorocarbon compounds such as CFC-11 were used as foaming agents, but they were prohibited because CFC compounds caused destruction of the ozone layer, and switched to HCFC-141b. Although switching to an HFC compound having a coefficient of zero has been performed, the HFC compound has a problem that it has a large GWP (global warming potential) and is currently expensive.

  Although a technique using pentane such as n-pentane, iso-pentane, cyclopentane or the like as a low-cost blowing agent instead of halogenated hydrocarbon compounds such as HFC compounds is known, pentanes are highly flammable. In addition, there is a problem that a large amount of cost is required for the equipment for fire prevention.

  There is no problem in the working environment and the global environment, and water is known as a low-cost foaming agent, and rigid polyurethane foams using water as the foaming agent are known (Patent Documents 1 and 2, etc.).

  The invention described in Patent Document 1 relates to a method for producing a water-foamed rigid polyurethane foam excellent in compressive strength, adhesive strength, and dimensional stability, and is characterized by using a liquid thickener at room temperature. . In Patent Document 1, there is a description that a general polyol compound is used. In Examples, sucrose-based polyether polyol, aliphatic amine-based polyether polyol, and aromatic amine-based polyether polyol are used. in use.

  The invention described in Patent Document 2 aims to improve the initial foaming property in the production of spray-foamed rigid polyurethane foam, and is characterized by the catalyst used. Also in Patent Document 2, there is a description that the polyol compound is a general polyether polyol or polyester polyol, and in the examples, sorbitol-based polyether polyol, amine polyol, and waste PET polyol are used.

Japanese Patent Laid-Open No. 06-184340 JP-A-11-130830

  However, any of the water-foamed rigid polyurethane foams using the ether-based polyols disclosed in the examples of the above-mentioned patent documents has a problem that the combustion resistance according to JIS A 9511 is poor. In addition, when an ester polyol is used, the combustion resistance tends to be improved, but the hydrolysis resistance of the polyester polyol is not sufficient, which causes a problem in the stability of the polyol composition. As a method for improving the flame resistance, a method of adding a large amount of flame retardant is conceivable. However, even if the amount of the flame retardant added to the foam in the examples of the above-mentioned patent documents is increased, It has also been found that it does not improve until it is met.

  The present invention relates to a polyol composition for rigid polyurethane foam, which uses a polyether polyol having water as a foaming agent and does not have a hydrolysis problem, and satisfies the JIS A 9511 standard of flame resistance, and the polyol composition. An object of the present invention is to provide a method for producing a rigid polyurethane foam using the above.

The present invention is a polyol composition comprising a polyol compound, a foaming agent, a catalyst and a foam stabilizer, and reacting with a polyisocyanate component to form a rigid polyurethane foam,
The blowing agent is water;
100 parts by weight of the polyol compound contains 60 parts by weight or more of a polyether polyol having a pentaerythritol having a hydroxyl value of 350 to 550 mgKOH / g as an initiator.

  The polyol composition having the above-described structure uses a polyether polyol having water as a foaming agent and does not have a hydrolysis problem, and forms a rigid polyurethane foam that satisfies the JIS A 9511 standard of flame resistance. is there.

  In the above-mentioned polyol composition, 100 parts by weight of the polyol compound preferably contains 40 parts by weight or less of an aromatic amine polyol. When there is too much addition amount of an aromatic amine polyol, the combustion resistance of the rigid polyurethane foam obtained will fall. The addition amount of the aromatic amine polyol is more preferably 30 parts by weight or less.

  The polyol composition having such a structure improves the miscibility of water as a blowing agent without impairing the combustion resistance, and forms a rigid polyurethane foam with high uniformity.

Another aspect of the present invention is a method for producing a rigid polyurethane foam, wherein a reactive composition obtained by mixing a polyol composition containing a polyol compound, a foaming agent and a foam stabilizer and a polyisocyanate component is foam-cured to obtain a rigid polyurethane foam. And
The blowing agent is water;
100 parts by weight of the polyol compound contains 60 parts by weight or more of a polyether polyol having a pentaerythritol having a hydroxyl value of 350 to 550 mgKOH / g as an initiator.

  According to the manufacturing method of such a configuration, a rigid polyurethane foam that uses water as a foaming agent, uses a polyether polyol that does not have a hydrolysis problem, and satisfies the JIS A 9511 standard of flame resistance is manufactured. Can do.

  In the manufacturing method of the above-mentioned rigid polyurethane foam, it is preferable that 100 parts by weight of the polyol compound contains 40 parts by weight or less of an aromatic amine polyol.

  According to the method for producing a rigid polyurethane foam having such a structure, a foam having a uniform cell can be obtained by improving the miscibility of water as a foaming agent without impairing the combustion resistance.

  In the polyol composition of the present invention, pentaerythritol is used as an initiator, and cyclic ether compounds such as ethylene oxide, propylene oxide, butylene oxide, preferably propylene oxide alone, or propylene oxide and ethylene oxide are subjected to ring-opening addition by a known technique. The polyol compound prepared is used.

  The aromatic amine polyol is obtained by ring-opening addition of a cyclic ether compound such as ethylene oxide, propylene oxide, butylene oxide or the like, preferably propylene oxide alone, or propylene oxide and ethylene oxide using an aromatic diamine as an initiator by a known technique. It is a functional polyol compound. As aromatic diamine which is an initiator, well-known aromatic diamine can be used without limitation. Specific examples include 2,4-toluenediamine, 2,6-toluenediamine, diethyltoluenediamine, 4,4'-diaminodiphenylmethane, p-phenylenediamine, o-phenylenediamine, naphthalenediamine and the like. The aromatic amine polyol is preferably one having 2,4-toluenediamine, 2,6-toluenediamine (TDA) or both as an initiator, The ratio is preferably 95/5 to 60/40. Commercial products start with TDA having a composition within this range. The hydroxyl value of the aromatic amine polyol is preferably 250 to 550 mgKOH / g.

  In the present invention, other polyol compounds may be used in combination as long as the intended combustion resistance is not impaired. As the polyol compound, a compound selected from glycerin, ethylene glycol, dipropylene glycol, and water is started. A polyether polyol as an agent is preferred. The amount of these polyol compounds added is preferably 20% by weight or less, more preferably 10% by weight or less, based on the total amount of polyol and aromatic amine polyol using pentaerythritol as an initiator.

  In the production of the rigid polyurethane foam of the present invention, in addition to the above components, catalysts, flame retardants, colorants, antioxidants and the like well known to those skilled in the art can be used. These components are generally contained in a polyol composition.

  Examples of the catalyst include N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetramethylhexamethylenediamine (Kaorizer No. 1), N, N, N ′, N ′, N-alkylpolyalkylenepolyamines such as N ″ -pentamethyldiethylenetriamine (Kaorizer No. 3), diazabicycloundecene (DBU), N, N-dimethylcyclohexylamine (Polycat-8), triethylenediamine, N— It is preferable to use tertiary amines such as methylmorpholine.

  It is also preferable to use a catalyst that forms an isocyanurate bond that contributes to an improvement in flame retardancy in the structure of the polyurethane molecule. For example, potassium acetate, potassium octylate, a quaternary ammonium salt catalyst (disclosed in JP-A-9-104734) is used. It can be illustrated. Some of the above-mentioned tertiary amine catalysts also promote the isocyanurate ring formation reaction. A catalyst that promotes the formation of isocyanurate bonds and a catalyst that promotes the formation of urethane bonds may be used in combination.

  In the present invention, addition of a flame retardant is also a preferred embodiment, and examples of suitable flame retardants include metal compounds such as halogen-containing compounds, organophosphates, antimony trioxide, and aluminum hydroxide. .

  Organophosphates are suitable additives because they also have an action as a plasticizer and thus have an effect of improving the brittleness of rigid polyurethane foam. It also has the effect of reducing the viscosity of the polyol composition. Examples of the organic phosphate esters include halogenated alkyl esters of phosphoric acid, alkyl phosphate esters, aryl phosphate esters, phosphonate esters, and the like. Specifically, tris (β-chloroethyl) phosphate (CLP, Daihachi Chemical), Tris (β-chloropropyl) phosphate (TMCPP, Daihachi Chemical), Tributoxyethyl phosphate (TBXP, Daihachi Chemical), Tributyl phosphate, Triethyl phosphate, Cresyl phenyl phosphate, Dimethyl methylphosphonate Etc., and one or more of these can be used. The addition amount of the organic phosphates is 40 parts by weight or less, preferably 5 to 40 parts by weight, and more preferably 10 to 25 parts by weight with respect to 100 parts by weight of the total polyol compound. If this range is exceeded, problems such as insufficient plasticization and flame retardant effects and deterioration of the mechanical properties of the foam may occur.

  As the foam stabilizer, a known foam stabilizer in the field of rigid polyurethane foam can be used without limitation. Specifically, foam stabilizers such as B-8465 (Gold Schmidt), SH-193, S-824-02, SZ-1704 (Toray Dow Corning Silicon) can be used. Two or more foam stabilizers may be used. The addition amount of the foam stabilizer is preferably 0.5 to 5% by weight with respect to 100 parts by weight of the polyol compound.

  The polyisocyanate compound that forms a rigid polyurethane foam by mixing and reacting with the polyol composition is easy to handle, fast in reaction, excellent in the physical properties of the resulting rigid polyurethane foam, and low in cost. For this reason, liquid MDI is used. As liquid MDI, Crude MDI (c-MDI) (Sumijoule 44V-10, Sumijoule 44V-20, etc. (manufactured by Sumika Bayer Urethane Co., Ltd.), Millionate MR-200 (Nippon Polyurethane Industry)), uretonimine-containing MDI (Millionate) MTL (manufactured by Nippon Polyurethane Industry) or the like is used. In addition to liquid MDI, other polyisocyanate compounds may be used in combination. As the polyisocyanate compound used in combination, a polyisocyanate compound known in the technical field of polyurethane can be used without limitation.

  In the production of the rigid polyurethane foam of the present invention, the equivalent ratio (NCO index) of isocyanate groups to active hydrogen groups is 1.0 to 1.7, more preferably 1.1 to 1.5.

  As a method for producing the rigid polyurethane foam of the present invention, a known method for producing a sandwich panel such as an injection molding method or a continuous production method can be used.

(Example 1)
Aliphatic polyether polyol (hydroxyl number = 410 mgKOH / g) 100 parts by weight as a polyol compound, pentaerythritol as an initiator, B-8465 (Gold Schmidt) 2 parts by weight as a foam stabilizer, Kaolinizer No. 1 part by weight of 1 (Kao), 15 parts by weight of TMCPP (Daihachi Chemical Industry) as a flame retardant, and 5 parts by weight of water of a blowing agent were stirred and mixed to obtain a polyol composition. This polyol composition and 192 parts by weight of Sumijoule 44V-20 (NCO concentration = 31%: Sumika Bayer Urethane), which is a polyisocyanate component, are mixed to form a reactive composition, and this reactive composition is foam-cured and cured. A rigid polyurethane foam was obtained.

  When the obtained rigid polyurethane foam was subjected to a combustion resistance test according to JIS A 9511, it was found to conform to the standard. The standard is that the fire spread distance of the rigid polyurethane foam sample is 60 mm or less and the after-flame time is within 120 seconds.

(Example 2)
A rigid polyurethane foam was obtained in the same manner as in Example 1 except that 100 parts by weight of an aliphatic polyether polyol (hydroxyl value = 450 mgKOH / g) using pentaerythritol as an initiator was used as the polyol compound.

  When the obtained rigid polyurethane foam was subjected to a combustion resistance test according to JIS A 9511, it was found to conform to the standard.

(Example 3)
70 parts by weight of an aliphatic polyether polyol (hydroxyl value = 450 mgKOH / g) using pentaerythritol as an initiator as a polyol compound and 30 parts by weight of an aromatic amine polyol (hydroxyl value = 400 mgKOH / g) using toluenediamine as an initiator A rigid polyurethane foam was obtained in the same manner as in Example 1 except that it was used.

  When the obtained rigid polyurethane foam was subjected to a combustion resistance test according to JIS A 9511, it was found to conform to the standard.

(Comparative Example 1)
A rigid polyurethane foam was obtained in the same manner as in Example 1 except that 100 parts by weight of an aliphatic polyether polyol (hydroxyl value = 350 mgKOH / g) using sorbitol as an initiator as a polyol compound was used.

  When the obtained rigid polyurethane foam was subjected to a combustion resistance test based on JIS A 9511, it did not conform to the standard.

(Comparative Example 2)
A rigid polyurethane foam was obtained in the same manner as in Example 1 except that 100 parts by weight of an aliphatic polyether polyol (hydroxyl value = 400 mgKOH / g) was used as the polyol compound, starting from sucrose and glycerin.

  When the obtained rigid polyurethane foam was subjected to a combustion resistance test based on JIS A 9511, it did not conform to the standard.

(Comparative Example 3)
A rigid polyurethane foam was obtained in the same manner as in Example 1 except that 100 parts by weight of an aliphatic polyether polyol (hydroxyl value = 400 mgKOH / g) using toluenediamine as an initiator was used as the polyol compound.

  When the obtained rigid polyurethane foam was subjected to a combustion resistance test based on JIS A 9511, it did not conform to the standard.

Claims (4)

A polyol composition comprising a polyol compound, a foaming agent, a catalyst and a foam stabilizer, and reacting with a polyisocyanate component to form a rigid polyurethane foam,
The blowing agent is water;
100 parts by weight of the polyol compound contains 60 parts by weight or more of a polyether polyol having a pentaerythritol having a hydroxyl value of 350 to 550 mgKOH / g as an initiator.   The polyol composition for rigid polyurethane foam according to claim 1, wherein 100 parts by weight of the polyol compound contains 40 parts by weight or less of an aromatic amine polyol. A method for producing a rigid polyurethane foam, wherein a reactive composition obtained by mixing a polyol composition containing a polyol compound, a foaming agent and a foam stabilizer and a polyisocyanate component is foam-cured to form a rigid polyurethane foam,
The blowing agent is water;
The method for producing a rigid polyurethane foam, wherein 100 parts by weight of the polyol compound contains 60 parts by weight or more of a polyether polyol having a pentaerythritol having a hydroxyl value of 350 to 550 mgKOH / g as an initiator.   The method for producing a rigid polyurethane foam according to claim 3, wherein 100 parts by weight of the polyol compound contains 40 parts by weight or less of an aromatic amine polyol.