JP4914653B2 - Polyol composition for rigid polyurethane foam and method for producing rigid polyurethane foam - Google Patents

Description

  The present invention relates to a polyol composition for an isocyanurate-modified rigid polyurethane foam having an isocyanurate group containing only water as a foaming agent, and a method for producing an isocyanurate-modified rigid polyurethane foam using the polyol composition.

  In the field of rigid polyurethane foam, as a technique for improving the heat resistance of the foam, the ratio of isocyanate group / active hydrogen group is set to 1 or more during the reaction, and a urethane is used in the polymer by using a so-called trimerization catalyst such as an alkali metal carboxylate. Isocyanurate-modified rigid polyurethane foams in which isocyanurate bonds other than bonds and urea bonds are formed are well known. As a foaming agent that is a component of a polyol composition for such rigid polyurethane foam, a chlorofluorocarbon compound has been conventionally used. However, since it has a property of destroying the ozone layer, water and HCFC having a smaller ozone layer destruction coefficient are used. A technique using -141b was developed (Patent Document 1). However, HCFC-141b still has a non-zero ozone depletion coefficient, and its use has been prohibited. A technique using only water as a blowing agent instead of HCFC-141b is known (Patent Document 2).

JP-A-9-104734 JP 2001-329036 A

  Since a panel using an isocyanurate-modified rigid polyurethane foam as a heat insulating material has higher heat resistance than other rigid polyurethane foams, it is often used for a building application. When using panels as building materials, it is required to pass the semi-incombustible standard. Moreover, since such a panel is also used as a siding board for an outer wall, it is required that deformation such as warpage does not occur even when it is exposed to high temperatures in summer and low temperatures in winter.

  According to the technique described in Patent Document 2, the NCO group / active hydrogen group equivalent ratio (NCO index) in the foam-forming reaction is 1.5 (index 150) or less. It does not satisfy. In order to obtain a foam that satisfies the quasi-incombustible regulations, it is conceivable that the NCO index is further increased to increase the concentration of isocyanurate groups. However, as in the technique of Patent Document 2, only water is used as a blowing agent. In some cases, increasing the NCO index increases the closed cell ratio of the resulting foam, and when used as an outer wall siding board, the panel may deform when exposed to high summer temperatures and low winter temperatures. There was found.

  In view of the above-mentioned problems of the known art, the present invention can produce an isocyanurate-modified rigid polyurethane foam that uses water as a foaming agent, satisfies the quasi-incombustible standard, and does not deform due to a temperature difference between summer and winter. An object of the present invention is to provide a polyol composition that can be produced and a method for producing an isocyanurate-modified rigid polyurethane foam that uses water as a foaming agent, satisfies quasi-incombustible standards, and does not deform due to a temperature difference between summer and winter.

The polyol composition of the present invention contains a polyol compound, a foaming agent, a catalyst, and a foam stabilizer, and is mixed with and reacted with a polyisocyanate component to form a rigid polyurethane foam having an isocyanurate group.
The blowing agent is water;
The catalyst includes an isocyanurate group forming catalyst selected from the group consisting of an alkali metal salt of an organic acid and a quaternary ammonium salt, and a tertiary amine catalyst,
The foam stabilizer includes (a) a cyclic dialkylpolysiloxane having an average number of Si—O bonds of 4 to 5, (b) (R ¹ ) Si (OR ² ) ₃ , (R ¹ ) ₂ Si (OR ² ). _{^{) 2, (R 1) 3}} Si (oR 2 at least one selected from the group consisting of) a Si ^(oR ₂₎ a silicone polymer which is co-hydrolytic condensation product of ₄ ^{(R 1} is or 1 carbon atoms 2 alkyl group or phenyl group, R ² is an alkyl group having 1 or 2 carbon atoms, R ¹ and R ² may be the same or different.), (C) polydimethylsiloxane and polyoxyalkylene Including three types of copolymerized silicone compounds which are graft copolymers of glycol,
The ratio of (a) cyclic dialkylpolysiloxane, (b) silicone polymer, and (c) copolymerized silicone compound is 1/3 to [(a) + (b)] / (c) (weight ratio). It is 1/5.

  By using a polyol composition having such a composition, it is possible to produce an isocyanurate-modified rigid polyurethane foam that uses only water as a foaming agent, satisfies the quasi-incombustible standard, and does not deform due to a temperature difference between summer and winter.

The method for producing a rigid polyurethane foam having an isocyanurate group of the present invention is to foam and cure a reactive composition mixed with a polyol composition containing a polyol compound, a foaming agent, a catalyst and a foam stabilizer and a polyisocyanate component. Yes,
The blowing agent is water;
The catalyst includes an isocyanurate group forming catalyst selected from the group consisting of an alkali metal salt of an organic acid and a quaternary ammonium salt, and a tertiary amine catalyst,
The foam stabilizer includes (a) a cyclic dialkylpolysiloxane having an average number of Si—O bonds of 4 to 5, (b) (R ¹ ) Si (OR ² ) ₃ , (R ¹ ) ₂ Si (OR ² ). _{^{) 2, (R 1) 3}} Si (oR 2 at least one selected from the group consisting of) a Si ^(oR ₂₎ a silicone polymer which is co-hydrolytic condensation product of ₄ ^{(R 1} is or 1 carbon atoms 2 alkyl group or phenyl group, R ² is an alkyl group having 1 or 2 carbon atoms, R ¹ and R ² may be the same or different.), (C) polydimethylsiloxane and polyoxyalkylene Including three types of copolymerized silicone compounds which are graft copolymers of glycol,
The NCO / OH equivalent ratio in the reaction between the polyol composition and the polyisocyanate component is 2.0 to 5.0.

  According to the manufacturing method having such a configuration, it is possible to manufacture an isocyanurate-modified rigid polyurethane foam that uses only water as a foaming agent, satisfies the quasi-incombustible standard, and does not deform due to a temperature difference between summer and winter. The NCO / OH equivalent ratio in the polymerization reaction is more preferably 2.5 to 4.5. The NCO / OH equivalent ratio here is the ratio of the isocyanate component excluding the isocyanate component consumed in the reaction with water (2 equivalents of NCO group to 1 mol of water) and a hydroxyl group such as a polyol compound.

The closed cell ratio of the isocyanurate-modified rigid polyurethane foam obtained by the production method of the present invention is preferably 50% or less and more preferably 34% or less because deformation due to temperature change is small. The density of the foam is preferably 45 kg / m ³ or less, and more preferably 40 kg / m ³ or less.

  The silicone polymer as the component (b) is used for the purpose of increasing the closed cell ratio to 60% or more in the production of a water-foamed rigid polyurethane foam. It has been found that the foaming and curing of the polyol composition and polyisocyanate forming the modified rigid polyurethane foam have an action of reducing the closed cell ratio, and the present invention has been completed.

  In the method for producing the above isocyanurate-modified rigid polyurethane foam, the ratio of (a) cyclic dialkylpolysiloxane, (b) silicone polymer, and (c) copolymer silicone compound is [(a) + (b)]. / (C) (weight ratio) is preferably 1/3 to 1/5.

  According to the manufacturing method having such a configuration, it is possible to more reliably manufacture an isocyanurate-modified rigid polyurethane foam that is not deformed by a temperature difference between summer and winter. When [(a) + (b)] / (c) (weight ratio) deviates from the above range, a cell roughening phenomenon may occur in which bubbles having a large cell diameter are formed in the obtained foam.

  In the above-described method for producing an isocyanurate-modified rigid polyurethane foam, the foam stabilizer is prepared by previously mixing three components of (a) a cyclic dialkylpolysiloxane, (b) a silicone polymer, and (c) a copolymerized silicone compound. It is preferable to mix with other polyol composition constituents.

  According to the production method having such a configuration, in the production of the polyol composition, the foam stabilizer and other components containing the polyol compound can be mixed uniformly, and a foam having a uniform cell diameter can be formed.

  As the polyol compound constituting the polyol composition of the present invention, a known polyol compound can be used. Specifically, aliphatic polyether polyols, aromatic polyether polyols, Mannich polyols, aliphatic amine polyether polyols, aromatic amine polyether polyols, aromatic ester polyols and the like known in the field of rigid polyurethane foams. Illustrated.

  Aliphatic polyether polyols include ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexylene glycol, cyclohexane dimethanol and the like as initiators. Ring-opening addition of at least one of propylene oxide and ethylene oxide using glycols, triols such as trimethylolpropane and glycerin, tetrafunctional alcohols such as pentaerythritol, polyhydric alcohols such as sorbitol and sucrose It is a polyfunctional oligomer obtained by polymerization. The polyether polyol having an aliphatic polyhydric alcohol as an initiator preferably has an average functional group number of 2.5 to 8 and a hydroxyl value of 300 to 600 mgKOH / g.

  The aromatic polyether polyol is produced in the same manner as the above polyether polyol, using an aromatic compound such as hydroquinone, bisphenol A, and xylylene glycol as an initiator. The aromatic polyether polyol preferably has an average functional group number of 2 to 4 and a hydroxyl value of 200 to 600 mgKOH / g.

  Mannich polyol is obtained by subjecting an active hydrogen compound obtained by the Mannich reaction of phenol and / or its alkyl-substituted derivative, formaldehyde and alkanolamine, or ring-opening addition polymerization of at least one of ethylene oxide and propylene oxide to this compound. It is a polyol compound having a hydroxyl value of 250 to 550 mgKOH / g and having 2 to 4 functional groups. As a commercial item of such a polyol compound, for example, there is DK-3776 (Daiichi Kogyo Seiyaku), which can be used.

  Examples of the aliphatic amine polyol include alkylene diamine polyols and alkanol amine polyols. These polyol compounds are polyfunctional polyol compounds having a terminal hydroxyl group obtained by ring-opening addition of at least one of ethylene oxide and propylene oxide using alkylene diamine or alkanol amine as an initiator. As the alkylene diamine, known compounds can be used without limitation. Specifically, use of alkylene diamine having 2 to 8 carbon atoms such as ethylene diamine, propylene diamine, butylene diamine, hexamethylene diamine, and neopentyl diamine is preferable. In the alkylene diamine-based polyol, the alkylene diamine as the initiator may be used alone or in combination of two or more. Examples of the alkanolamine include monoethanolamine, diethanolamine, and triethanolamine. The number of functional groups of the polyol compound using alkylene diamine as the initiator is 4, and the number of functional groups of the polyol compound using alkanolamine as the initiator is 3.

  Aromatic amine polyol is a cyclic ether compound such as ethylene oxide, propylene oxide, butylene oxide, preferably a propylene oxide alone, or a tetrafunctional polyol compound obtained by ring-opening addition of propylene oxide and ethylene oxide using an aromatic diamine as an initiator. It is. 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. Of these, the use of toluenediamine (2,4-toluenediamine, 2,6-toluenediamine, or a mixture thereof) is particularly preferred in terms of excellent properties such as heat insulation and strength of the rigid polyurethane foam obtained. The value is preferably 250 to 550 mgKOH / g.

  The aromatic ester polyol is an aromatic dicarboxylic acid glycol ester, terephthalic acid, phthalic acid, isophthalic acid and the like, ethylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, and an average molecular weight of 150 to 500. An ester polyol having a hydroxyl group terminal based on a glycol with a glycol such as polyoxyethylene glycol is exemplified. The aromatic ester polyol preferably has an average functional group number of 2 to 3 and a hydroxyl value of 100 to 600 mgKOH / g.

  The polyol compound to be used preferably contains an aromatic ester polyol from the viewpoint of enhancing the flame retardancy of the foam, and more specifically contains 30 parts by weight or more of the aromatic ester polyol in 100 parts by weight of the polyol compound. Is preferable, and it is more preferable to contain 35-65 weight part.

In the present invention, the (b) silicone polymer used as the foam stabilizer component is (R ¹ ) Si (OR ² ) ₃ , (R ¹ ) ₂ Si (OR ² ) ₂ , (R ¹ ) ₃ Si (OR ² ). ) And at least one selected from the group consisting of Si (OR ² ) ₄ and co-hydrolyzing and condensing using water and a catalyst to form a polysiloxane bond. R ¹ and R ² may be the same or different and are preferably a methyl group or an ethyl group. Further, (a) cyclic dialkylpolysiloxane can also be produced by a known method, and is preferably cyclic dimethylsiloxane. The mixing ratio of (a) cyclic dialkylpolysiloxane and (b) silicone polymer is preferably 1/9 to 8/2 in weight ratio. Commercially available products can be used as the composition containing (a) cyclic dialkylpolysiloxane and (b) silicone polymer in such a range, and specific examples include F701 (Shin-Etsu Chemical Co., Ltd.).

  (C) The copolymer silicone compound is a compound used as a foam stabilizer in the technical field of polyurethane foam. In the present invention, among these known foam stabilizers, those having a Si content of 10 to 40% by weight are preferably used. Specifically, SH-193 (Si = 30 wt%; Toray Dow Corning Silicon), S-824-02 (Si = 25 wt%; Nihon Unicar), SZ-1704 (Si = 25 wt%; Nihon Unicar), F501 ( A foam stabilizer such as Si = 25 wt%; Shin-Etsu Chemical Co., Ltd.) can be used. Two or more kinds of foam stabilizers (copolymerized silicone compounds) having polyoxyalkylene glycol may be used, or (a) a cyclic dialkylpolysiloxane may be contained.

  As described above, the foam stabilizer component is prepared by mixing in advance a foam stabilizer that is (a) a cyclic dialkylpolysiloxane, (b) a silicone polymer, and (c) a copolymerized silicone compound. It is preferably used for the production of the composition.

  The foam stabilizer concentration [(a) + (b) + (c)] in the polyol composition is preferably 1 to 3% by weight, more preferably 1.5 to 2.5% by weight. preferable. Moreover, in the reactive composition in reaction of a polyol composition and polyisocyanate, it is preferable that it is 0.3 to 1 weight%, and it is more preferable that it is 0.4 to 0.6 weight%. If the added amount of the foam stabilizer is too small, the foam yield of the foam obtained is increased and the deformation resistance is lowered. If the added amount of the foam stabilizer is too large, the bubbles become rough.

  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.

  The isocyanurate group-forming catalyst includes an alkali metal salt of an organic carboxylic acid having 1 to 20 carbon atoms such as potassium acetate, potassium propionate, potassium 2-ethylhexanoate (potassium octylate), and N- (2-hydroxypropyl). -N- (2-hydroxyethyl) -N, N-dimethylammonium octylate, N-hydroxyalkyl-N, N, N-trialkylammonium salt, etc., compounds disclosed in JP-A-9-104734 At least one compound selected from quaternary ammonium salt catalysts such as

  The tertiary amine catalyst is a urethane bond forming catalyst or a foaming catalyst. Specifically, N, N, N ′, N′-tetramethylethylenediamine or N, N, N ′, N′-tetramethylhexamethylene is used. N-alkyl polyalkylene polyamines such as diamine (kaolyzer No. 1), N, N, N ′, N ′, N ″ -pentamethyldiethylenetriamine (kaolyzer No. 3), diazabicycloundecene (DBU), N , N-dimethylcyclohexylamine (Polycat-8), triethylenediamine, N-methylmorpholine, and the like can be used.

  In the production of the rigid polyurethane foam of the present invention, in addition to the above components, flame retardants, colorants, antioxidants and the like well known to those skilled in the art can be used.

  Suitable flame retardants include halogen-containing compounds, organophosphates such as TCEP and TMCPP, and metal compounds such as antimony trioxide and aluminum hydroxide. Among these, use of organophosphates such as TCEP and TMCPP is preferable, and the addition amount is preferably 5 to 35 parts by weight with respect to 100 parts by weight of the polyol compound.

  As a method for producing the isocyanurate-modified 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 of rigid polyurethane foam production)
As a polyol compound, 50 parts by weight of an aromatic ester polyol (hydroxyl value 250 mg KOH / g) composed of phthalic acid and diethylene glycol and 50 parts by weight of a polyoxypropylene polyol (hydroxyl value 400 mg KOH / g) using toluenediamine as an initiator are used. 10 parts by weight of TMCPP (Daihachi Chemical Industry) with respect to 100 parts by weight of the compound, F701 and F501 (Shin-Etsu Chemical) as foam stabilizers, potassium octylate (hexoate K-15: TA Chemical), tertiary Kaloraza No. which is an amine catalyst. 1 (Kao-No. 1: Kao) and a foaming agent water were mixed to obtain a polyol composition. The blending ratio of the foam stabilizer, catalyst and water is shown in the upper part of Table 1. F701 and F501 were mixed in advance and mixed with other polyol composition constituents.

  The obtained polyol composition and the polyisocyanate component (Sumijoule 44V-20 (Suika Bayer Urethane)) were mixed and stirred at the blending ratio (parts by weight) shown in the upper part of Table 1, and the thickness was 0.27 mm. An isocyanurate-modified rigid polyurethane foam sandwich panel (width: 360 mm) having a foam layer thickness of 17 mm was produced by foaming and curing in an oven at 70 ° C. using a color steel plate surface material and aluminum vapor-deposited kraft paper as a back material. The addition amount of F701 and F501 in Table 1 is% by weight in the mixture (reactive composition) of the polyol composition + polyisocyanate component. The obtained panel was evaluated as described below, and the results are shown in the lower part of Table 1.

(Evaluation)
1) Foam density (kg / m ³ )
The face material was removed from the panel, and a 100 mm × 100 mm foam sample was cut out and weighed to calculate the density.

2) Deformation resistance (cooling cycle test)
A sample having a length of 100 mm was cut out from the manufactured sandwich panel having a width of 360 mm, and 7 cycles of heating at 70 ° C. for 8 hours and cooling at −20 ° C. for 16 hours were performed, and the deformation of the sample was measured. In the case of deformation, the maximum height difference was measured in the case of warpage, and the surface irregularities were visually evaluated. The evaluation results were displayed according to the following criteria.
○: Warpage is 3.0 mm or less and there is no surface irregularity.
X: Warpage of 3.0 mm or more or surface unevenness.
3) Flame resistance (corn calorie test)
Sample of (99 ± 1) mm × (99 ± 1) mm is cut out from the sandwich panel, and the maximum heat generation rate (heat generation rate) when heated for 5 minutes at a radiant heat intensity of 50 kW / m ² according to ISO-5660 The total calorific value was measured. This measurement method is a test method defined as corresponding to the standard according to the corn calorimeter method at the Building Comprehensive Testing Laboratory, which is a public institution prescribed in Article 108-2 of the Building Standard Law Enforcement Ordinance. The quasi-incombustible standards are as follows, and those that satisfy this standard are accepted and those that do not meet are rejected.
B) The total calorific value for 10 minutes is 8.0 MJ / m ² or less.
B) The maximum heat generation rate for 10 minutes should not exceed 200 kW / m ² for 10 seconds or more.
C) There should be no through-holes (cracks, holes) penetrating to the back side, which is harmful to fire prevention, in 10 minutes.

  From the above results, the isocyanurate-modified rigid polyurethane foam using the polyol composition of the present invention was excellent in deformation resistance and met the quasi-incombustible standard in the evaluation of combustibility. The foam having an NCO / OH ratio in the range of 2.5 to 4.5 had a particularly low maximum heat generation rate and excellent combustion resistance. About Comparative Examples 2 and 3, since the deformation resistance was not good, the flammability was not evaluated.

Claims (3)

In a method for producing a rigid polyurethane foam, a reactive composition mixed with a polyol composition containing a polyol compound, a foaming agent, a catalyst and a foam stabilizer and a polyisocyanate component is foamed and cured to obtain a rigid polyurethane foam having an isocyanurate group There,
The blowing agent is water;
The catalyst includes an isocyanurate group forming catalyst selected from the group consisting of an alkali metal salt of an organic acid and a quaternary ammonium salt, and a tertiary amine catalyst,
The foam stabilizer includes (a) a cyclic dialkylpolysiloxane having an average number of Si—O bonds of 4 to 5, (b) (R ¹ ) Si (OR ² ) ₃ , (R ¹ ) ₂ Si (OR ² ). _{^{) 2, (R 1) 3}} Si (oR 2 at least one selected from the group consisting of) a Si ^(oR ₂₎ a silicone polymer which is co-hydrolytic condensation product of ₄ ^{(R 1} is or 1 carbon atoms 2 alkyl group or phenyl group, R ² is an alkyl group having 1 or 2 carbon atoms, R ¹ and R ² may be the same or different.), (C) polydimethylsiloxane and polyoxyalkylene Including three types of copolymerized silicone compounds which are graft copolymers of glycol,
The amount of the foam stabilizer [(a) + (b) + (c)] in the reactive composition is 0.3 to 1% by weight,
A method for producing an isocyanurate-modified rigid polyurethane foam, wherein an NCO / OH equivalent ratio in the reaction between the polyol composition and the polyisocyanate component is 2.0 to 5.0. The ratio of (a) cyclic dialkylpolysiloxane, (b) silicone polymer, and (c) copolymerized silicone compound is 1/3 to [(a) + (b)] / (c) (weight ratio). method for producing isocyanurate-modified rigid polyurethane foam according to claim 1, characterized in that 1/5. The foam stabilizer is characterized in that three components of (a) cyclic dialkylpolysiloxane, (b) silicone polymer, and (c) copolymerized silicone compound are mixed in advance and mixed with other components of the polyol composition. A process for producing an isocyanurate-modified rigid polyurethane foam according to claim 1 or 2 .