JP2006328171A - Polyol composition for rigid polyurethane foam and method for producing rigid polyurethane foam - Google Patents

Abstract

A polyol composition capable of producing a rigid polyurethane foam that uses only water as a foaming agent and has excellent heat insulation, strength, and dimensional stability, and a rigid polyurethane foam using the polyol composition A manufacturing method is provided.
A polyol composition comprising a polyol compound, a foaming agent and a foam stabilizer, and mixed with a polyisocyanate component to form a rigid polyurethane foam, wherein the foaming agent is water and the polyol compound contains resin fine particles. As the foam stabilizer, 0.5 to 6.0 parts by weight of the medium active foam stabilizer and 1.0 to 3.5 parts by weight of the low activity foam stabilizer with respect to 100 parts by weight of the polyol compound in total. It is set as the polyol composition for rigid polyurethane foams containing this.
[Selection figure] None

Description

  The present invention relates to a polyol composition for rigid polyurethane foam for water foaming and a method for producing a water foaming rigid polyurethane foam.

  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 CFC compounds were prohibited because they 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.

  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 (for example, Patent Documents 1 and 2).

  The polyol compound constituting the polyol composition for producing the rigid polyurethane foam disclosed in Patent Document 1 is composed of 10 to 50% by weight of polyoxypropylene polyol starting from sorbitol and propylene glycol and 20 aromatic amine polyol. It contains ~ 30% by weight.

  The invention disclosed in Patent Document 2 is a rigid polyurethane foam having a closed cell ratio of 10 to 50% using a polyol compound containing acrylonitrile and vinyl acetate copolymer fine polymer particles.

Japanese Patent Laid-Open No. 6-239956 JP 2000-256434 A

  However, the rigid polyurethane foam produced using the polyol composition described in Patent Document 1 is not sufficient in strength and heat insulation, and the rigid polyurethane foam disclosed in Patent Document 2 is not sufficient in heat insulation. There is a need for improvement.

  The present invention relates to a polyol composition capable of producing a rigid polyurethane foam excellent in heat insulation, strength and dimensional stability, using only water as a foaming agent, and a rigid polyurethane foam using the polyol composition. An object of the present invention is to provide a manufacturing method.

The polyol composition for rigid polyurethane foam of the present invention is a polyol composition comprising a polyol compound, a foaming agent and a foam stabilizer, and mixed with a polyisocyanate component to form a rigid polyurethane foam,
The blowing agent is water;
The polyol compound contains resin fine particles,
As the foam stabilizer, 0.5 to 6.0 parts by weight of a medium active foam stabilizer and 1.0 to 3.5 parts by weight of a low activity foam stabilizer with respect to 100 parts by weight of a total of polyol compounds. It is characterized by.

  The rigid polyurethane foam manufactured using the polyol compound having such a structure is a rigid polyurethane foam that uses only water as a foaming agent and is excellent in heat insulation, strength, and dimensional stability.

  In the above-mentioned polyol composition for rigid polyurethane foam, the resin fine particles are preferably copolymer resin fine particles of acrylonitrile and vinyl acetate.

  With this configuration, it is possible to produce a rigid polyurethane foam that is particularly excellent in heat insulation, strength, and dimensional stability.

Another aspect of the present invention is a method for producing a rigid polyurethane foam in which a polyol composition containing a polyol compound, a foaming agent and a foam stabilizer and a polyisocyanate component are mixed to form a foamed stock solution composition, and the foamed stock solution composition is foamed and cured. Because
The blowing agent is water;
The polyol compound contains resin fine particles,
As the foam stabilizer, 0.5 to 6.0 parts by weight of a medium active foam stabilizer and 1.0 to 3.5 parts by weight of a low activity foam stabilizer with respect to 100 parts by weight of a total of polyol compounds. It is characterized by.

  By the said structure, the rigid polyurethane foam excellent in heat insulation, intensity | strength, and dimensional stability can be manufactured using only water as a foaming agent.

  In the method for producing a rigid polyurethane foam, the resin fine particles are preferably copolymer resin fine particles of acrylonitrile and vinyl acetate.

  With this configuration, it is possible to produce a rigid polyurethane foam that is particularly excellent in heat insulation, strength, and dimensional stability.

  As the resin fine particles used in the polyol composition for water-foaming rigid polyurethane foam and the method for producing water-foaming rigid polyurethane foam of the present invention, known resin fine particles contained in the polyol for polyurethane foam can be used. Specifically, homopolymer fine particles such as acrylonitrile, styrene, vinyl acetate, acrylic monomers, and copolymer fine particles of two or more monomers selected from these monomers can be used. Among these resin fine particles, it is preferable to use fine particles of a copolymer of acrylonitrile (AN) and vinyl acetate (VAc) as described above, and AN / VAc = 40/60 to 15/85 (weight ratio). It is preferable. Moreover, it is preferable that the resin fine particle in the polyol compound whole quantity which comprises a polyol composition is 0.2 to 1.0 weight%.

  The polyol compound containing the resin fine particles can be produced by a known method. For example, a resin produced by a bulk polymerization method or a solution polymerization method is pulverized into fine particles, and a resin fine powder obtained by classification as necessary is added to and mixed with a polyol compound. A resin obtained by an emulsion polymerization method Examples include a method of adding an emulsion containing fine particles as it is, a method in which a monomer is dissolved or dispersed in a polyol compound, a radical polymerization initiator such as AIBN or BPO is added, heated, and polymerized to obtain a resin fine particle polyol compound. The Among these, the method of polymerizing in a polyol compound to form resin fine particles is most preferable because the particles are less likely to settle even when left for a long period of time and a stable polyol composition is obtained.

  As the polyol compound in which the resin fine particles are dispersed, it is also preferable to use a commercially available product, specifically XRAG-7102, WB-918 (Asahi Glass) and the like can be used.

  As the polyol compound, a polyol compound known in the technical field of rigid polyurethane foam can be used without limitation. Polyol compounds include aromatic amine polyols, aliphatic amine polyols, polyether polyols using aliphatic polyhydric alcohols as initiators, aromatic polyether polyols using bisphenol A as an initiator, aromatic ester polyols, Mannich polyols Etc. are exemplified.

  The aromatic amine-based polyol is a polyfunctional polyether polyol compound having a terminal hydroxyl group obtained by ring-opening addition of at least one of ethylene oxide and propylene oxide using an aromatic diamine as an initiator. As the initiator, known aromatic diamines 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 that the obtained rigid polyurethane foam has excellent properties such as heat insulation and strength. The aromatic amine-based polyol preferably has an average functional group number of 3 to 5 and a hydroxyl value of 250 to 600 mgKOH / g.

  Examples of the aliphatic amine-based polyether polyol include alkylene diamine-based polyols and alkanolamine-based 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. Among these, the use of alkylenediamine having a small number of carbon atoms is more preferable, and the use of a polyol compound having ethylenediamine or propylenediamine as an initiator is particularly 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 and diethanolamine. The aliphatic amine polyether polyol preferably has an average functional group number of 3 to 4 and a hydroxyl value of 250 to 600 mgKOH / g.

  Polyether polyols using aliphatic polyhydric alcohol as initiators include ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, neopentyl as initiators. Propylene oxide using glycols such as glycol, cyclohexylene glycol and cyclohexanedimethanol, triols such as trimethylolpropane and glycerin, tetrafunctional alcohols such as pentaerythritol, polyhydric alcohols such as sorbitol and sucrose, etc. And a polyfunctional oligomer obtained by ring-opening addition polymerization of at least one of ethylene oxide. 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 45 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 ring-opening addition polymerization of at least one of ethylene oxide and propylene oxide to an active hydrogen compound obtained by the Mannich reaction of phenol and / or its alkyl-substituted derivative, formaldehyde and alkanolamine, or 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.

  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 300 to 700 mgKOH / g.

  You may use a crosslinking agent as a component which comprises the polyol composition for rigid polyurethane foams of this invention. As the crosslinking agent, low molecular weight polyhydric alcohols used in the technical field of polyurethane can be used. Specifically, trimethylolpropane, glycerin, pentaerythritol, triethanolamine and the like are exemplified.

  The above polyol compounds may be used alone or in combination of two or more. When two or more kinds of polyol compounds are used in combination, the resin fine particles may be dispersed in any polyol compound or may be formed by polymerization in any polyol compound and mixed with other polyol compounds. It may be dispersed in the final mixture or polymerized in a mixture of polyols. The polyol composition preferably has an average hydroxyl value of 200 to 500 mg KOH / g, an average functional group number of 3 to 6, and more preferably an average functional group number of 3 to 5.

  In the polyol composition for rigid polyurethane foam for water foaming and the method for producing water foaming rigid polyurethane foam of the present invention, 0.5 to 6.0 parts by weight of the moderately active foam stabilizer is added to 100 parts by weight of the total polyol compound. And 1.0 to 3.5 parts by weight of a low activity foam stabilizer. For the activity of the foam stabilizer, a polyol composition having the composition shown in Table 1 was used, and 144.5 parts by weight of the polyol composition and 157.0 parts by weight of Sumidur 44V-20 (Suika Bayer Urethane), a crude MDI, were mixed. The thermal conductivity (λ) of the rigid polyurethane foam produced was measured, and λ was 0.0189 W / m · K or more and less than 0.0196 W / m · K, medium activity, and λ was 0.0196 W / m · K. Those exceeding K were regarded as low activity. A foam stabilizer that forms a foam having a λ of less than 0.0189 W / m · K is highly active. That is, when HCFC-141b was used as a foaming agent, the higher the activity, the higher the heat-insulating foam with low thermal conductivity.

  Commercially available foam stabilizers are preferably used, and examples of medium active foam stabilizers include SF-2940, SH-193, L-5420, SF-2936, and SZ-1649 (Toray Dow Corning Silicon). Is done. Examples of the low activity foam stabilizer include SF-2945, SF-2935, SZ-1605, BY-10-540 (Toray Dow Corning Silicon).

  The rigid polyurethane foam obtained by using the method for producing a polyol composition or rigid polyurethane foam of the present invention preferably has a closed cell ratio p of 70 <p ≦ 85, and 70 <p ≦ 80 (%). It is more preferable. Within this range, a rigid polyurethane foam having an excellent balance between shrinkage resistance and heat insulation is obtained.

  The present invention is characterized in that a moderately active foam stabilizer and a low activity foam stabilizer are used in combination. Even if the polyol composition is changed, by adjusting the addition amount of these two kinds of foam stabilizers, closed cells The rate can be adjusted.

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

  Examples of the catalyst include triethylenediamine, N-methylmorpholine, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetramethylhexamethylenediamine (Kaorizer No. 1), diaza It is preferable to use tertiary amines such as bicycloundecene (DBU) and N, N-dimethylcyclohexylamine (Polycat-8).

  The use of a catalyst that forms an isocyanurate bond that contributes to improving the flame retardancy in the structure of the polyurethane molecule is also preferred, and examples thereof include potassium acetate, potassium octylate, and quaternary ammonium salts. 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. .

  However, when an excessive amount of powdery flame retardant such as antimony trioxide is added excessively, there may be a problem that the foaming behavior of the foam is affected.

  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, based on 100 parts by weight of the 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.

  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 Sumitomo Bayer Urethane Co., Ltd.), Millionate MR-200 (Nippon Polyurethane Industry)), uretonimine-containing MDI (Millionate MTL) Manufactured by Nippon Polyurethane Industry) or the like. In addition to liquid MDI, other polyisocyanate compounds may be used in combination. As the polyisocyanate compound to be used in combination, polyisocyanate compounds well 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.

  The polyol composition for rigid polyurethane foam and the method for producing rigid polyurethane foam of the present invention can be used for producing continuously produced foam such as spray foam, slabstock foam and sandwich panel, and sandwich panel by high pressure injection molding. .

<Evaluation / Measurement>
(Foam density)
A 100 × 100 × 100 (mm) sample was cut out from the core portion of a rigid polyurethane foam obtained by free foaming without using a mold, and the density was determined by measuring the weight.
(Shrink resistance)
A foam sample with a thickness of 25 mm and a length and width of 200 mm was cut out from the core of a 60 mm thick panel obtained in the following production example, and subjected to an exposure test for 1 week under conditions of 70 ° C. and humidity 95% RH, and the change in thickness The rate was measured and used as the dimensional change rate. The evaluation results are indicated by ◯ when the dimensional change rate is less than 1%, Δ when 1 to 3%, and x when more than 3%.

(Closed cell rate)
Accu Pyc 1330 (Shimadzu Corporation) was used as a measuring device, and the closed cell ratio was measured.
(Thermal conductivity)
The thermal conductivity of the rigid polyurethane foam was measured using a thermal conductivity measuring device AUTO-Λ HC-074 (manufactured by Eiko Seiki Co., Ltd.), and the measurement conditions were measured according to JIS A 9511.

<Example of production of polyol composition and rigid polyurethane foam>
(Raw materials used)
[Polyol compound]
Polyol A: WB-918 (polyol compound in which a copolymer resin fine powder of acrylonitrile and vinyl acetate is dispersed in a polyether polyol compound; hydroxyl value = 365 mg KOH / g; Asahi Glass Urethane)
-Polyol B: GR-84 (polyol added with propylene oxide using shoecloth as the main initiator; hydroxyl value 450 mgKOH / g; Mitsui Takeda Chemical)
[Foam stabilizer]
-Foam stabilizer A: SF-2937 (λ = 0.0185 W / m · K: high activity; Toray Dow Corning Silicon)
Foam stabilizer B: SH-193 (λ = 0.0193 W / m · K: medium activity; Toray Dow Corning Silicon)
Foam stabilizer C: SZ-1605 (λ = 0.0204 W / m · K: low activity; Toray Dow Corning Silicon)
[Polyisocyanate]
Sumidur 44V-20 (Sumika Bayer Urethane) was used. The NCO / OH equivalent ratio was 1.10.

(Examples 1 and 2 and Comparative Examples 1 to 5)
According to a conventional method, based on the composition shown in the upper part of Table 2, the polyol component (composition) is first adjusted to adjust the temperature to 20 ° C., and then mixed with the polyisocyanate component that is also temperature adjusted to 20 ° C. The product was foamed and cured to prepare a rigid polyurethane foam panel having a thickness of 60 mm. The numerical value in a table | surface shows a weight part. The rigid polyurethane foam panel was cut into predetermined dimensions and evaluated for density, shrinkage resistance (dimensional stability), closed cell ratio, and thermal conductivity.

  From the results shown in Table 2, the foams of Examples 1 and 2 according to the present invention had good characteristics in both shrinkage resistance (dimensional stability) and heat insulation. On the other hand, a foam using only a highly active foam stabilizer (Comparative Example 3) and a foam using only a moderately active foam stabilizer (Comparative Example 4) were obtained using a polyol compound containing resin fine particles. ) And the foam using only the low activity foam stabilizer (Comparative Example 5) were not satisfactory in balance between shrinkage resistance and heat insulation. Moreover, the foam using the polyol compound which does not contain resin fine particles had a large shrinkage.

Claims (4)

A polyol composition comprising a polyol compound, a foaming agent and a foam stabilizer, and mixed with a polyisocyanate component to form a rigid polyurethane foam,
The blowing agent is water;
The polyol compound contains resin fine particles,
As the foam stabilizer, 0.5 to 6.0 parts by weight of a medium active foam stabilizer and 1.0 to 3.5 parts by weight of a low activity foam stabilizer with respect to 100 parts by weight of a total of polyol compounds. A polyol composition for rigid polyurethane foams.   The polyol composition for rigid polyurethane foam according to claim 1, wherein the resin fine particles are copolymer resin fine particles of acrylonitrile and vinyl acetate. A method for producing a rigid polyurethane foam comprising mixing a polyol composition containing a polyol compound, a foaming agent and a foam stabilizer and a polyisocyanate component to form a foamed stock solution composition, and foaming and curing the foamed stock solution composition,
The blowing agent is water;
The polyol compound contains resin fine particles,
As the foam stabilizer, 0.5 to 6.0 parts by weight of a medium active foam stabilizer and 1.0 to 3.5 parts by weight of a low activity foam stabilizer with respect to 100 parts by weight of a total of polyol compounds. A process for producing a rigid polyurethane foam characterized by   The method for producing a rigid polyurethane foam according to claim 3, wherein the resin fine particles are copolymer resin fine particles of acrylonitrile and vinyl acetate.