JPH10168152A - Production of rigid polyurethane foam and composition for rigid polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to obtain the subject foam, excellent in heat insulating properties and resin stability and useful as a refrigerator and a freezer, etc., by using a polyether polyol using bisphenol A as an initiator as a part of a polyol component. SOLUTION: This rigid polyurethane foam is obtained by mixing (A) an organic polyisocyanate which is a polyisocyanate having an aromatic ring with (B) a polyol component containing (B1 ) a polyol comprising a polyether polyol or a polyester polyol and (B2 ) a polyol which is a polyether polyol obtained by using bisphenol A as an initiator (preferably the one prepared by conducting the addition polymerization of bisphenol A with ethylene oxide or propylene oxide) and having 200-700mgKOH/g hydroxyl value. Furthermore, a polyol at 3-50wt.% concentration of the component B2 is preferably used as the component B in an amount corresponding to 40-100 pts.wt., based on 100 pts.wt. component A and expressed in terms of the component B1 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As a foaming agent for producing a rigid polyurethane foam, chlorofluorocarbon (hereinafter referred to as CFC), particularly trichlorofluoromethane (R11) has been used. However, CFC
Due to its chlorine content, there are concerns about environmental problems such as destruction of the ozone layer in the stratosphere and global warming. For global environmental protection purposes, the production and use of CFCs has been banned and replaced with other alternatives. Currently,
Hydrochlorofluorocarbon (HCFC) having a low ozone depletion potential is often used as a blowing agent. For example, HCFC141b (1,1-dichloro-1-
Fluoroethane), HCFC22 (chlorodifluoromethane), and HCFC142b (1-chloro-1,1-difluoroethane) have been commercialized and have already been applied as foaming agents for heat insulating materials.

[0003] However, HCFCs also contain chlorine atoms in their molecules, and thus have little effect on the ozone layer. It is required and a gradual reduction in use is being implemented. Therefore, from the viewpoint of global environmental protection,
The use of a blowing agent that does not affect ozone depletion at all has been newly proposed. Some applications already use hydrocarbon-based blowing agents, such as cyclopentane, which already contain no chlorine atoms and have no risk of destroying the ozone layer. Rigid polyurethane foams using cyclopentane as a foaming agent have been widely used as heat insulating materials for refrigerators, refrigerators, building materials and vehicles because of their excellent heat insulating properties.

[0004]

Although cyclopentane is the most suitable as a blowing agent for the environment, it has some problems. There is a problem that cyclopentane itself has a high thermal conductivity of gas, and the produced rigid polyurethane foam is inferior in heat insulation performance to products using the conventional foaming agent R141b. Further, since cyclopentane has a strong chemical attack property, the stability of the resin of the manufactured product tends to decrease.

It is known to use secondary polyols as part of the polyol. Known and widely used auxiliary polyols have no effect of improving the compressive strength of the mechanical properties of the manufactured rigid polyurethane foam, but have been favorably used in the past for improving the flowability of the rigid polyurethane foam. . However, when cyclopentane is used as a foaming agent, the flowability of the rigid urethane foam is improved, but the cell size of the cells cannot be reduced, so that the thermal conductivity of the product is not improved. It was still left. An object of the present invention is to provide a rigid polyurethane foam having good heat insulating performance and resin stability.

[0006]

The present invention provides a method for producing a rigid polyurethane foam by mixing an organic polyisocyanate component and a polyol component, wherein the organic polyisocyanate component is a polyisocyanate having an aromatic ring, A method for producing a rigid polyurethane foam, wherein the polyol component comprises a first polyol comprising a polyether polyol and / or a polyester polyol, and a second polyol which is a polyether polyol having bisphenol A as an initiator. provide. The present invention relates to bisphenol A
Is used as at least a part of the polyol component.

Further, the present invention provides (1) an organic polyisocyanate comprising a polyisocyanate having an aromatic ring,
(2) a first polyol comprising a polyether polyol and / or a polyester polyol; (3) a second polyol which is a polyether polyol having bisphenol A as an initiator; (4) a blowing agent comprising a hydrocarbon and water; (5) A composition for a rigid polyurethane foam comprising a catalyst is provided. In the present invention, (6) a foam stabilizer and (7) additives (for example, a flame retardant and a filler) are used as necessary.

[0008] As the organic polyisocyanate (1),
Polyisocyanates such as toluylene diisocyanate (TDI), diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate (polymeric MDI), and modified polyisocyanates thereof are used alone or in combination.

The organic polyisocyanate (1) may be a modified polyvalent isocyanate, that is, a product obtained by a partial chemical reaction of an organic di- and / or polyisocyanate. The modified polyisocyanates include urea, buret, allophanate, carbodiimide, isocyanurate and / or di- and / or polyisocyanates containing urethane groups, for example, aromatic polyisocyanates containing urethane groups. The NCO content of the modified polyvalent isocyanate may be 33.6 to 15% by weight, preferably 31 to 21% by weight. Examples of modified polyisocyanates include low molecular weight diols, triols, dialkylene glycols, trialkylene glycols or 15
4,4'-diphenylmethane diisocyanate or 2,4- or 2,6-toluylene-diisocyanate modified with a polyoxyalkylene glycol having a molecular weight of up to 00.

The organic polyisocyanate (1) is N
It may be an NCO group-containing prepolymer having a CO content of 25 to 9% by weight, preferably 21 to 14% by weight. It is prepared from the polyester polyols and / or preferably polyether polyols described below and 4,4'-diphenylmethane-diisocyanate, 2,4- and / or 2,6-toluylene-diisocyanate or polymeric MDI. Furthermore, a liquid carbodiimide group and / or isocyanurate ring-containing polyisocyanate having an NCO content of 33.6 to 15% by weight, preferably 31 to 21% by weight (for example, 4,4′-, 2,4′- and / or Or 2,2′-diphenylmethane-diisocyanate and / or
Alternatively, it is prepared on the basis of 2,4- and / or 2,6-toluylene-diisocyanate. ) Are preferred.

The first polyol (2) is a polyether polyol or a polyester polyol. Polyether polyols are starting materials containing 2 to 8, preferably 3 to 8, reactive hydrogen molecules bonded (eg ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, bisphenol A, triethanolamine, ethylenediamine, triethylenediamine (TEDA),
Sugar or the like) to which an alkylene oxide (for example, propylene oxide (PO) and / or ethylene oxide (EO)) is added.

Starting materials include, for example, water, organic dicarboxylic acids such as succinic, adipic, phthalic and terephthalic acids, aliphatic and aromatic N-monoalkyl and N, N-dialkyl substituted. Diamines having from 1 to 4 carbon atoms in good alkyl chains, such as ethylenediamine, diethylenetriamine, triethylenetetramine, which may be mono- and dialkyl-substituted,
1,3-propylenediamine, 1,3- or 1,4-butylenediamine, 1,6-hexamethylenediamine, phenylenediamine, 2,3-, 2,4- and 2,6-toluylenediamine and 4, 4'-, 2,4'- and 2,2'-diamino-diphenylmethane.

Another example of a starting material is an alkanolamine such as ethanolamine, diethanolamine, N
-Methyl- and N-ethyl-ethanolamine, N-
Methyl- and N-ethyl-diethanolamine and triethanolamine and ammonia. Other examples of starting materials are polyhydric, especially dihydric and / or trihydric or higher alcohols, such as ethanediol, propanediol-1,2 and propanediol-1,3, diethylene glycol, dipropylene glycol, butanediol. -1,4, hexanediol-1,6, glycerin, trimethylolpropane, pentaerythritol, sorbitol and sucrose.

Suitable alkylene oxides may be compounds having 2 to 4 carbon atoms in the alkylene chain. These alkylene oxides can be used alone or as a mixture. Alkylene oxides are preferred, for example, 1,2- or 2,3-butylene oxide and 1,2-propylene oxide, styrene oxide and especially ethylene oxide and 1,2-propylene oxide.

[0015] The polyether polyol is preferably from 3 to
It has a functionality of 8, particularly preferably 3 to 6, and a hydroxyl value of preferably 300 to 850 mg KOH / g, particularly preferably 350 to 800 mg KOH / g.

As the polyester polyol, a polyester polyol produced from a polycarboxylic acid and a polyhydric alcohol, for example, polyethylene terephthalate can be used. Suitable polyester polyols include, for example,
It can be prepared from a polyvalent carboxylic acid having 2 to 12 carbon atoms and a diol having 2 to 12 carbon atoms, preferably 2 to 6 carbon atoms.

[0017] The polycarboxylic acid may be a dicarboxylic acid. Examples of dicarboxylic acids are succinic, glutaric, adipic, suberic, azelaic, sebacic, decanedicarboxylic, maleic, phthalic, isophthalic and terephthalic acids. Instead of the free dicarboxylic acid, it is also possible to use the corresponding dicarboxylic acid derivatives, for example dicarboxylic monoesters or diesters with alcohols having 1 to 4 carbon atoms, or dicarboxylic anhydrides.

Polyhydric alcohols are dihydric and higher polyhydric alcohols. Examples of diols include ethanediol, diethylene glycol, 1,2- or 1,
3-propanediol, dipropylene glycol, 1,
4-butanediol, 1,5-pentanediol, 1.6
-Hexanediol, 1,10-decanediol, glycerin and trimethylolpropane. Preferably, ethanediol, diethylene glycol, 1,4-
Butanediol, 1,5-pentanediol, 1,6-hexanediol and mixtures of the abovementioned diols.
Particularly preferred is a mixture of 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol. Furthermore, lactones, for example polyester polyols from ε-hydroxycarboxylic acids, can be used. First
The amount of the polyol (2) depends on the amount of the organic polyisocyanate 10
0 to 100 parts by weight, especially 60 to 9 parts by weight,
It is preferably 0 parts by weight.

The second polyol (3) is a polyol obtained by adding an alkylene oxide using bisphenol A as a starting material. The second polyol (3) is preferably a polyol obtained by addition polymerization of bisphenol A with ethylene oxide and / or propylene oxide. The hydroxyl value of the second polyol (3) is 200 to 700, particularly 200 to 500 mgKOH /
g is preferable. The amount of the second polyol (3) used is preferably 3 to 50 parts by weight, particularly preferably 10 to 30 parts by weight, based on 100 parts by weight of the total polyol.

The blowing agent (4) may be a carbon-containing compound having 2 to 8 carbon atoms. The blowing agent (4) can be selected from the group consisting of alkanes, cycloalkanes, dialkyl ethers, cycloalkylene ethers, and fluoroalkanes (for example, compounds having a fluorine atom and a hydrogen atom). Examples of alkanes are propane, n-butane, isobutane, n-pentane, isopentane, n-hexane. Examples of cycloalkanes are cyclobutane,
Cyclopentane, cyclohexane, cycloheptane and cyclooctane. Examples of dialkyl ethers are dimethyl ether, methyl ethyl ether or diethyl ether. An example of a cycloalkylene ether is furan. Examples of fluoroalkanes are trifluoromethane, difluoromethane, difluoroethane, tetrafluoromethane and heptafluoropropane.

The amount of the carbon-containing compound is 3 to 50 parts by weight, preferably 5 to 100 parts by weight of the organic polyisocyanate.
Preferably, it is 40 parts by weight. The foaming agent (4)
It may contain water. The amount of water is 0 to 5 parts by weight, especially 0.5 part by weight, per 100 parts by weight of the organic polyisocyanate.
It is preferably from 3 to 3 parts by weight. The blowing agent (4) is preferably a mixture of water and a hydrocarbon selected from cyclopentane, n-pentane, and isopentane.

As the catalyst (5), a conventionally known amine catalyst or metal catalyst is used. As the amine catalyst,
For example, triethylenediamine, tetramethylhexamethylenediamine, pentamethyldiethylenetriamine,
Tertiary amines such as methyl morpholine. Examples of the metal catalyst include organometallic compounds such as stannaus octoate, dibutyltin dilaurate, and lead octylate. The amount of the catalyst (5) is 0.001 to 5 parts by weight, particularly 0.1 to 100 parts by weight of the organic polyisocyanate.
It is preferably from 0.5 to 2 parts by weight.

As the foam stabilizer (6), an ordinary organic silicon compound or the like can be used. The amount of the foam stabilizer (6) is preferably 0 to 5 parts by weight, particularly preferably 1 to 3 parts by weight, based on 100 parts by weight of the organic polyisocyanate.

The additives (7) include, for example, foam stabilizers, foam control agents, fillers, dyes, pigments, flame retardants, hydrolysis inhibitors and fungicides. Examples of the filler include carbon black and calcium carbonate.

Suitable flame retardants are, for example, tricresyl phosphate, tris- (2-chloroethyl) phosphate, tris- (1,3-dichloropropyl) phosphate, tris- (2,3-dibromopropyl) phosphate And tetrakis- (2-chloroethyl) -ethylene phosphate. In addition to the aforementioned halogen-substituted phosphates, also inorganic flame retardants, such as red phosphorus, aluminum oxide hydrate, antimony trioxide, arsenic oxide, ammonium polyphosphate and calcium sulfate or cyanuric acid derivatives, such as melamine, or at least 2
There are classes of flame retardants, for example, mixtures of ammonium polyphosphate and melamine. The amount of the additive (7) is
1-4 based on 100 parts by weight of organic polyisocyanate
It is preferably 0 parts by weight, particularly preferably 5 to 20 parts by weight.

The rigid polyurethane foam can be suitably produced by a discontinuous method or a continuous method, a prepolymer method or a one-stage foaming method using a well-known mixing apparatus. A particularly preferred method is a processing method according to a two-component method (using component (A) and component (B)), wherein component (A) comprises organic polyisocyanate (1) and component (B) ) Comprises components other than the organic polyisocyanate (1) (that is, components (2) to (7)). Isoanate index (NCO / NCO reactive group ratio) is 95
To 130, particularly preferably 105 to 115.

Component (A) and component (B) are 15 to 9
Mixing at a temperature of 0 ° C., preferably at a temperature of 15-35 ° C.,
It is then poured into an open, temperature-controlled mold, where the reaction mixture is foamed at normal pressure to avoid peripheral compression. In order to produce a laminated composite, for example, a foamable reaction mixture is injected or sprayed on the back side of the facing, which is foamed and cured to a rigid polyurethane foam.

The rigid polyurethane foam is preferably 2
Density of 0~100kg / m ³ and 0.0140 to 0.02
It has a thermal conductivity of 30 kcal / m · h · ° C. Rigid polyurethane foams are preferably suitable for insulated interlayers of laminated composites and for injection foaming of cavities in refrigeration and refrigeration equipment, especially refrigerators and refrigeration equipment, and are also useful as jacket insulation for hot water storage equipment. . It can also be used for heat insulation of heated objects.

[0029]

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. Examples 1 to 3 and Comparative Examples 1 to 3 50 parts by weight of polyol A and 50 parts by weight of polyol B were added to an amine catalyst (N, N-dimethylcyclohexylamine) (a necessary amount for adjusting the reactive gel time to about 50 seconds). And 2 parts by weight of a foam stabilizer (L-5421, manufactured by Nippon Unicar Co., Ltd.) and 0.5 part by weight of water to prepare a polyol mixture. To the polyol mixture, 11 parts by weight of cyclopentane as a blowing agent was mixed to prepare a final polyol mixture.

Polyol A: a hydroxyl value of 450 mg KOH
/ G of sugar as a starting material and propylene oxide (PO) added thereto. Polyol B: a polyol to which PO is added using toluylenediamine (TDA) having a hydroxyl value of 400 mgKOH / g as a starting material.

A part of the above-mentioned main polyol (100 parts by weight) was replaced with the following subpolyols (polyols C, D, E and F).
And a polyol mixture was prepared. Polyol C: a polyol to which PO has been added using bisphenol A having a hydroxyl value of 290 mgKOH / g as a starting material. Polyol D: a polyol to which PO has been added using propylene glycol having a hydroxyl value of 225 mgKOH / g as a starting material. Polyol E: a polyol to which PO has been added using trimethylolpropane having a hydroxyl value of 380 mgKOH / g as a starting material. Polyol F: a polyol obtained by adding PO using glycerin having a hydroxyl value of 250 mgKOH / g as a starting material.

Based on the mixing ratio shown in Table 1, the above-mentioned polyol mixture (polyol mixture, cyclopentane) and polymeric MDI were mixed and foamed with a mixer. The urethane raw material temperature at that time was adjusted to 20 ° C. The urethane mixture was stirred with a mixer and adjusted to 45 ° C. at 600 × 4.
It was poured into a 00 × 50 mm aluminum mold, and after 7 minutes, the molded product (hard polyurethane foam) was released from the mold. Table-Result of foam properties of demolded molded product
Put together in 1.

The physical properties were measured as follows. Cream time The time from when the polyol mixture and the isocyanate solution are stirred and mixed until the reaction mixture becomes creamy-white and the foam rises. Gel time The time from mixing the undiluted reaction solution to the time when the foam draws a thread on the stick pierced into the foam being foamed. Free foam density Foam density when free foaming is performed in a veneer box with dimensions of 150 mm x 300 mm x 150 mm.

The compressive strength of a 50 mm cubic sample taken from the core of the foam was compressed in the direction perpendicular to the flow, and the stress when the displacement reached 10% (10 mm / min. Head speed). The dimensional change when a 50 mm cubic sample taken from the core of a low-temperature dimensional stability foam was kept at -30 ° C for 48 hours. The case where the dimensional change rate is 3% or less is regarded as good. 200 × 200 × 2 cut out from core part of thermal conductivity foam
A 5 mm sample is measured with a thermal conductivity measuring device (Auto Lambda) manufactured by Eiko Seiki. Average measured temperature 23.7 ° C.

A photograph of the form is taken with a cell size microscope, the number (n) of cells per unit length (l) is counted, and the average cell size is set to 1 / n. Unit: 200 (width) x 50 (thickness) x 2000 inclined at 45 m fluidity
A urethane mixture is poured into a mold (length) mm, the just pack weight (W) is determined, and the free density (D) at that time is defined as fluidity = W / D. The fluidity of Comparative Example 1 is set to 100%. The higher the value of the fluidity, the better the fluidity.

[0036]

Table 1 Comparative Example Comparative Example Comparative Example Comparative Example Comparative Example Comparative Example Comparative Example Comparative Example 1 2 3 4 5 6 7 Polyol mixture 100 90 80 80 90 80 90 80 Polyol C Polyol D 10 20 Polyol E 10 20 Polyol F 10 20 Cyclopentane 11 11 11 11 11 11 11 11 Polymeric MDI 134 129 125 133 132 130 130 126 Cream time (seconds) 9 9 9 9 10 9 9 Gel time (seconds) 49 50 50 49 50 49 50 50 Foam Density 35.8 34.6 34.5 34.2 34.6 34.0 34.3 (kg / m ³ ) Compressive strength 1.68 1.66 1.69 1.57 1.69 1.59 1.68 (kg / cm ² ) Low temperature dimensional stability Good Good Good Good Good Good Good Thermal conductivity × 10 ^-4 181 181 183 182 182 182 181 182 (kcal / MHC) cell size (μm) 300 320 310 290 300 310 32 Liquidity (%) 100 104 108 103 107 104 109

[0037]

[Table 2]

As can be seen from Table 1, the urethane systems using polyols D, E, and F as a part of the polyols in Comparative Examples 2 to 7 have a higher urethane flowability than Comparative Example 1 as a standard. Although improved, the compressive strength and thermal conductivity of the foam have not been improved.

However, the systems of Examples 1 and 2 in which a polyol using bisphenol A as an initiator is used as a part have a high foam compressive strength, a small cell size of the foam, and consequently a urethane. The thermal conductivity of the foam was also improved.

[0040]

By using an aromatic polyether having bisphenol A as an initiator (hereinafter referred to as bisphenol A polyol) as a part of the polyol, it is effective in miniaturizing the cells of the rigid polyurethane foam,
Due to the small cell size and uniform air bubbles, the thermal conductivity of the foam is reduced and the heat insulation performance is improved. In addition, since the resin stability of the manufactured rigid polyurethane foam is improved, the compressive strength is improved, and there is no decrease in foam strength due to the chemical attack of cyclopentane.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 75:04 (72) Inventor Junji Urano 3-13-26 Kuguchi, Amagasaki City, Hyogo Prefecture Sumitomo Bayer Urethane Co., Ltd. (72) Invention Person Koji Nakatani 3-13-26 Kuguchi, Amagasaki-shi, Hyogo Sumitomo Bayer Urethane Co., Ltd.

Claims (2)

[Claims] 1. A method for producing a rigid polyurethane foam by mixing an organic polyisocyanate component and a polyol component, wherein the organic polyisocyanate component is a polyisocyanate having an aromatic ring, and the polyol component is a polyether polyol and / Or a first polyol comprising a polyester polyol,
And a second polyol, which is a polyether polyol having bisphenol A as an initiator. 2. An organic polyisocyanate comprising (1) an organic polyisocyanate having an aromatic ring, (2) a first polyol comprising a polyether polyol and / or a polyester polyol, and (3) a polyether polyol having bisphenol A as an initiator. A composition for a rigid polyurethane foam comprising a certain second polyol, (4) a blowing agent comprising a hydrocarbon and water, and (5) a catalyst.