HK1087420B - Polyol composition for hard polyurethane foam and method for producing hard polyurethane foam - Google Patents

Description

Polyol composition for rigid polyurethane foam and process for producing rigid polyurethane foam

Technical Field

The present invention relates to a rigid polyurethane foam polyol composition and a method for producing a rigid polyurethane foam, wherein the rigid polyurethane foam polyol composition contains a blowing agent component 1, 1, 1, 3, 3-pentafluoropropane (HFC-245fa) as an essential component.

Background

As a blowing agent for a rigid polyurethane foam which is an excellent heat insulator, 1-dichloro-1-fluoroethane (HCFC-141b) having a small ozone layer depletion coefficient has been used. HCFC-141b is a blowing agent having a low ozone depletion factor but is not zero, and is completely eliminated at the end of 2003, because of the viewpoint of global environmental conservation.

As a method for producing a rigid polyurethane foam using a blowing agent in place of HCFC-141b, a technique using a low boiling point hydrocarbon such as n-pentane or cyclopentane (Japanese patent application No. 3181700), and a technique using low boiling point halogenated hydrocarbon compounds such as HFC-245fa and HFC-365mfc containing no chlorine (Japanese patent application laid-open No. 2002-201251) have been known.

However, low boiling hydrocarbons such as n-pentane and cyclopentane are highly flammable compounds. Therefore, strict measures against fire should be taken in the production process of a polyol composition containing these compounds as a blowing agent, the production process of a rigid polyurethane foam using the polyol composition, the waste treatment process of crushing the waste of the rigid polyurethane foam, and the like. Further, it is necessary to renew the equipment in a conventional plant for producing a rigid polyurethane foam. Further, there arises a problem that equipment costs including disaster prevention countermeasures become very expensive. Further, the flame retardancy of rigid polyurethane foams using pentane as a blowing agent is inferior to that of conventional products using HCFC-141b as a blowing agent.

HFC-365mfc has been registered in non-hazardous materials according to the standards of the Japanese fire Act. However, it has been confirmed in German standards that the polyol composition has a flash point at-27 ℃ and the polyol composition containing the same as a blowing agent has a problem that the polyol composition is sometimes handled as a hazardous material and cannot be stored as a hazardous material according to its composition, which is regarded as a hazardous material type 4, type 1 petroleum type, and the polyol composition containing HCFC-141b as a blowing agent. Further, HFC-365mfc has a problem that the compatibility with the polyol compound which is the main component of the polyol composition is poor.

On the other hand, HFC-245fa is a blowing agent which has no risk of ignition and does not need to be handled as a hazardous substance, and has a boiling point of 15 ℃ and a high vapor pressure at ordinary temperature. Therefore, when HFC-245fa is used as a blowing agent, there arises a problem that a container such as a tank or a petroleum tank containing the polyol composition is expanded particularly in summer, and at the time of opening the cap, a polyol composition stock solution is discharged by vaporization of the blowing agent, and the content thereof is reduced by vaporization of the blowing agent, so that a rigid polyurethane foam having a predetermined density cannot be obtained.

JP-A2002-201251 discloses a technique of using HFC-245fa and HFC-365mfc in combination as a blowing agent, but the effect of suppressing the vapor pressure is insufficient, and further improvement is required.

Disclosure of Invention

The purpose of the present invention is to provide a polyol composition for rigid polyurethane foam which uses HFC-245fa as a blowing agent and has a suppressed vapor pressure, and a method for producing rigid polyurethane foam.

The present invention is a polyol composition for rigid polyurethane foam comprising at least a polyol compound, a blowing agent, a foam stabilizer and a catalyst, and being mixed with an isocyanate component containing a polyisocyanate compound and foam-hardened to form a polyol composition for rigid polyurethane foam, wherein the blowing agent comprises 1, 1, 1, 3, 3-pentafluoropropane (HFC-245fa) as a main component, at least one compatibilizer selected from the group consisting of N, N-Dimethylacetamide (DMA), N-methylpyrrolidone (NMP), gamma-butyrolactone (GBL) and methoxypropyl acetate (MPA) and 1, 1, 1, 3, 3-pentafluorobutane (HFC-365mfc), and the HFC-245fa/HFC-365mfc is not less than 60/40 (weight ratio), (HFC-245fa + HFC-365 mfc)/(compatibilizer) 95/5-60/40 (weight ratio).

By using HFC-245fa as a blowing agent and adding HFC-365mfc and at least one compatibilizer selected from DMA, NMP, GBL and MPA, the vapor pressure of HFC-245fa can be suppressed while maintaining the foaming characteristics and the physical properties and heat insulation properties of the rigid polyurethane foam obtained.

HFC-365mfc is a compound having a boiling point of 40.2 ℃ and has good compatibility with HFC-245fa, and functions as a blowing agent and also functions to lower the vapor pressure.

When the weight ratio HFC-245fa/HFC-365mfc is less than 60/40, the content of HFC-365mfc increases, resulting in a decrease in flash point, and although the polyol composition belongs to the dangerous goods class 4, it is sometimes judged to be petroleum with high flammability.

When the weight ratio of (HFC-245fa + HFC-365 mfc)/(compatibilizer) is more than 95/5, the addition effect cannot be sufficiently exhibited because the ratio of the compatibilizer is too small. On the other hand, when the weight ratio is less than 60/40, the physical properties of the foam may be deteriorated due to an excessive ratio of the compatibilizer. The weight ratio of (HFC-245fa + HFC-365 mfc)/(compatibilizer) is more preferably 85/15-70/30.

The compatibilizer has excellent compatibility with HFC-245fa, HFC-365mfc and polyol compounds. By using the compatibilizer, the compatibility between the foaming agent and the polyol compound is improved. Particularly in the above composition range, the uniformity of cells in the foam is improved, so-called cell collapse is improved, and the excellent effect of improving the adhesion to the surface material can be obtained.

The compatibilizer may be previously mixed with HFC-245fa and, if necessary, HFC-365mfc to prepare a blowing agent composition itself, and the composition having a lowered vapor pressure may be mixed with a polyol compound or the like. Further, each component may be mixed with a component such as a polyol compound to form a polyol composition.

The present invention is a method for producing a rigid polyurethane foam by mixing an isocyanate component and a polyol composition, foaming the mixture, and curing the mixture to form a rigid polyurethane foam, wherein the polyol composition contains at least a polyol compound, a blowing agent, a foam stabilizer, and a catalyst, the blowing agent contains 1, 1, 1, 3, 3-pentafluoropropane (HFC-245fa) as a main component, and 1, 1, 3, 3-pentafluorobutane (HFC-365mfc) and a compatibilizer selected from at least one of N, N-Dimethylacetamide (DMA), N-methylpyrrolidone (NMP), γ -butyrolactone (GBL), and methoxypropyl acetate (MPA), and the HFC-245fa/HFC-365mfc are not less than 60/40 (weight ratio), (HFC-245fa + HFC-365 mfc)/compatibilizer 95/5 to 60/40 (weight ratio is 95/5 to 60/40 (weight ratio) ).

According to the above production method, a rigid polyurethane foam using HFC-245fa as the main component of the blowing agent can be produced without significantly modifying the production apparatus for the purpose of fire prevention by using the same production apparatus as that used when HCFC-141b is used as the blowing agent.

Drawings

FIG. 1 is a schematic view showing a method for measuring the adhesion strength between a rigid polyurethane foam and a surface material.

Detailed Description

The polyol composition for rigid polyurethane foam of the present invention contains at least a polyol compound, a foam stabilizer and a catalyst in addition to a blowing agent.

The polyol compound is not limited and any known polyol compound for rigid polyurethane foam can be used. Examples of the polyol compound include a polyol compound having a tertiary amino group, an aliphatic polyol compound, and an aromatic polyol compound.

The polyol compound having a tertiary amino group is a polyfunctional polyol compound obtained by subjecting an alkylene oxide, specifically, one or more of Propylene Oxide (PO), Ethylene Oxide (EO), Styrene Oxide (SO), tetrahydrofuran, and the like to a ring-opening addition polymerization reaction using a primary or secondary amine as an initiator.

Examples of the primary or secondary amine as an initiator for the tertiary amino group-containing polyol compound include aliphatic primary or secondary monoamines such as ammonia, methylamine and ethylamine, aliphatic primary or secondary polyamines such as ethylenediamine, hexamethylenediamine and N, N' -dimethylethylenediamine, aromatic primary or secondary monoamines or polyamines such as aniline, diphenylamine, tolylenediamine, diphenylmethanediamine and N-methylaniline, and alkanolamines such as monoethanolamine and diethanolamine.

The aliphatic polyol is a polyfunctional oligomer obtained by ring-opening addition polymerization of an aliphatic or alicyclic polyfunctional active hydrogen compound and an alkylene oxide, specifically, one or more cyclic ethers such as Propylene Oxide (PO), Ethylene Oxide (EO), Styrene Oxide (SO), tetrahydrofuran, and the like, using a polyol compound as an initiator.

Examples of the polyol compound initiator for the aliphatic polyol compound include glycols such as ethylene glycol, propylene glycol, 1, 4-butanediol, 1, 3-butanediol, 1, 6-hexanediol and neopentyl glycol, triols such as trimethylolpropane and glycerol, 4-functional alcohols such as pentaerythritol, polyhydric alcohols such as sorbitol and sucrose, and water.

Examples of the aromatic polyol include a polyol compound obtained by adding the above alkylene oxide to a polyfunctional active hydrogen compound having an aromatic ring in the molecule, a polyol compound which is an ester of an aromatic polycarboxylic acid and a polyol, and the like.

Specific examples of the polyol compound obtained by adding the above alkylene oxide to the polyfunctional active hydrogen compound include compounds obtained by ring-opening addition of at least one of PO, EO and SO to hydroquinone, bisphenol A and the like.

Specific examples of the ester of an aromatic polycarboxylic acid and a polyhydric alcohol include ester polyol compounds obtained by reacting a hydroxyl group of ethylene glycol, diethylene glycol, or the like with terephthalic acid, phthalic acid, isophthalic acid, or the like.

The polyol compound preferably has a hydroxyl value of 200 to 600 mgKOH/g. Among these polyol compounds, the polyol compound containing tertiary amine groups or aliphatic polyol can be used to obtain the effect of reducing the viscosity of the polyol composition.

The catalyst used in the polyol composition for rigid polyurethane foam of the present invention may be any known catalyst for rigid polyurethane foam, and is not limited thereto. Specific examples thereof include tertiary amines such as triethylenediamine, N-methylmorpholine, N, N, N ', N' -tetramethylethylenediamine, N, N, N ', N' -tetramethylhexamethylenediamine, N, N-dimethylcyclohexylamine, and Diazabicycloundecene (DBU), and metal catalysts such as dibutyltin dilaurate, dibutyltin diacetate, and tin octylate, which are capable of catalyzing a urethane reaction.

It is preferable to use a small amount of water as the blowing agent because the properties of the resulting rigid polyurethane foam can be improved.

It is preferable to use a catalyst that forms an isocyanurate bond contributing to an increase in flame retardancy in the molecular structure of polyurethane. Examples of the catalyst include potassium acetate and potassium octylate. Some of the tertiary amine catalysts described above promote the isocyanurate ring-forming reaction. Further, a catalyst for promoting the formation of an isocyanurate bond and a catalyst for promoting the formation of a urethane bond may be used in combination.

As the foam stabilizer, any known foam stabilizer for rigid polyurethane foams can be used without limitation. As the foam stabilizer, polydimethylsiloxane and a graft copolymer or block copolymer of polydimethylsiloxane and polyalkylene oxide are generally used. The polyalkylene oxide is polyethylene oxide, polypropylene oxide, or a random copolymer or block copolymer of ethylene oxide and propylene oxide having an average molecular weight of 5000 to 8000.

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

Examples of the flame retardant include halogen-containing compounds, organic phosphates, antimony trioxide, and metal compounds such as aluminum hydroxide.

These flame retardants, such as organic phosphoric acid esters, have a problem of reducing the physical properties of rigid polyurethane foams if added in excess. In addition, there is a problem that excessive addition of a metal compound powder such as antimony trioxide affects the foaming behavior of the foam in some cases. Therefore, the amount of these substances to be added is limited to a range in which the above-mentioned problems do not occur.

Organic phosphates act as plasticizers and thus have the effect of improving the brittleness of rigid polyurethane foams, and are therefore preferred additives. In addition, the polyol composition also has a viscosity-reducing effect. As the organic phosphate, there can be used a halogenated alkyl ester, an alkyl phosphate, an aryl phosphate, a phosphonate ester of phosphoric acid, and the like, and specific examples thereof include tris (2-chloroethyl) phosphate (CLP, manufactured by Daita chemical Co., Ltd.), tris (. beta. -chloropropyl) phosphate (TMCPP, manufactured by Daita chemical Co., Ltd.), tributoxyethyl phosphate (TBXP, manufactured by Daita chemical Co., Ltd.), tributyl phosphate, triethyl phosphate, tolylphenyl phosphate, dimethyl methylphosphonate, and the like. In addition, one or more of these compounds may be used. The amount of the organic phosphate is preferably 5 to 30 parts by weight based on 100 parts by weight of the total polyol compound. If the amount exceeds this range, problems such as insufficient flame retardancy and plasticizing effect, and a decrease in mechanical strength of the foam may occur.

The polyisocyanate compound which is mixed with the polyol composition and reacted to form the rigid polyurethane foam is preferably liquid MDI. By using liquid MDI, the ease of handling, the speed of reaction, and the physical properties of the resulting rigid polyurethane foam can be improved, and the cost can be reduced. As the liquid MDI, crude MDI (c-MDI) (44V-10, 44V-20, etc. (manufactured by Sumitomo Bayer Urethane Co., Ltd.), uretoimine-containing MDI (Milionate MTL; manufactured by Polyurethane industries, Japan) and the like were used. Among these polyisocyanate compounds, crude MDI is particularly preferably used from the viewpoint that the rigid polyurethane foam formed is excellent in physical properties such as mechanical strength and the like and the cost is low.

Other polyisocyanate compounds may be added to the liquid MDI and used. As the polyisocyanate compound, a diisocyanate compound or a polyisocyanate compound known in the art of polyurethane technology can be used without limitation.

The polyol composition for rigid polyurethane foam of the present invention can be used for producing rigid polyurethane foam for continuous production such as slabstock foam and sandwich panel, injection molded rigid polyurethane foam sandwich panel, spray foam, etc.

Examples

The constitution and effects of the present invention will be described below based on specific examples and the like.

Polyol composition the same was used except that the composition of the blowing agent composition used was changed. The components other than the blowing agent composition and the compounding ratio are shown below.

TABLE 1

The composition (weight% of each component based on 100% by weight of the blowing agent composition) and the amount added (weight part based on 100 parts by weight of the total amount of the polyols) of the blowing agent composition are shown in tables 2 to 4, based on 100 parts by weight of the polyol compound of the composition. The amount of the blowing agent composition added was adjusted so that the density of the rigid polyurethane foam at the time of free foaming was 25kg/m³。

Rigid polyurethane foams are made by conventional methods. That is, in the composition shown in Table 1, rigid polyurethane foams were obtained by mixing and stirring the components excluding the isocyanate component and the blowing agent composition to adjust the polyol composition to a temperature of 20 ℃ and then mixing and stirring the polyol composition and the polyol component adjusted to a temperature of 20 ℃ at a ratio of NCO/OH equivalent ratio of 1.70 to foam and cure the same.

As the blowing agent composition, those having compositions shown in tables 2 to 4 and obtained by mixing in advance were used.

< evaluation >

(Absolute vapor pressure)

50g of a polyol composition stock solution adjusted to a predetermined blending ratio was charged into a SUS container having a capacity of 100ml, the container was completely sealed, and the container was degassed by freezing with liquid nitrogen. Then, the resulting mixture was left standing in a thermostat at 40 ℃ to measure the vapor pressure (absolute pressure) P. The decompression rate was calculated according to the following formula. P₀The vapor pressure of the blowing agent was only 245fa (comparative example 2).

Decompression rate (%) < 100 (P)₀-P)/P₀

(compressive Strength)

A cube of 50 mm. times.50 mm was cut out from A foam freely foamed in A container, and the measurement was carried out in accordance with JIS-A-9511 (foamed plastic heat insulating material).

(dimensional stability)

A cube of 100 mm. times.100 mm was cut out from a foam which was freely foamed in a container, and the amount of change in dimensions was measured after being left to stand at-30 ℃ for 24 hours.

(adhesiveness)

A freely foamed foam was produced on a kraft paper surface material, and as shown in fig. 1, a 5cm wide notch was inserted from the surface material to which the foam was adhered, and the end portion was torn off and stretched with a spring balance to measure the adhesion strength. The direction of the arrow in fig. 1 is the direction of tensile measurement.

(bubble stability)

The foam which had foamed freely in the container was observed by eye. The evaluation was compared with a conventional foam using HCFC-141b as a blowing agent, and the evaluation results were expressed based on the following criteria.

O: the bubbles are uniform and fine, and are the same as HCFC-141b foam.

And (delta): there was bubble collapse, slightly worse than the HCFC-141b foam.

X: the bubbles were broken seriously and the foaming was not good.

< evaluation results >

The evaluation results are shown in the lower part of tables 2 to 4. The blowing agent compositions shown in Table 2 were compositions in which HFC-245fa and gamma-butyrolactone were previously mixed. The blowing agent compositions shown in Table 3 are compositions containing 3 components HFC-245fa, HFC-365mfc and gamma-butyrolactone. The blowing agent compositions shown in Table 4 were prepared by mixing HFC-245fa, HFC-365mfc and a compatibilizer, such as methoxypropyl acetate, N-methylpyrrolidone and N, N-dimethylacetamide. These results show that by using the blowing agent composition of the present invention, the vapor pressure of the blowing agent can be greatly reduced, the same treatment method as that used in the previous polyol composition using HCFC-141b can be used, and also the adhesion to surface materials, bubble stability, are improved. However, the dimensional stability of the foam using HCFC-141b as a blowing agent was-17%, and therefore in comparative example 1 where (HFC-245fa + HFC-365 mfc)/gamma-butyrolactone was less than 60/40 (weight ratio) (too much gamma-butyrolactone), (HFC-245fa + HFC-365 mfc)/gamma-butyrolactone was 90/10 and HFC-245fa/HFC-365mfc (weight ratio) was less than 60/40 (too much HFC-365mfc), either of them reduced the dimensional stability as compared with the foam using HCFC-141b as a blowing agent. In addition, in comparative example 2 in which no compatibilizer was used, the adhesion was not satisfied.

TABLE 2

The foaming agent comprises the following components: weight ratio of

TABLE 3

The foaming agent comprises the following components: weight ratio of

TABLE 4

Claims (7)

1. A polyol composition for rigid polyurethane foam which comprises at least a polyol compound, a blowing agent, a foam stabilizer and a catalyst and which is mixed with an isocyanate component containing a polyisocyanate compound and is foamed and cured to form a rigid polyurethane foam,

the foaming agent mainly comprises 1, 1, 1, 3, 3-pentafluoropropane, a compatilizer selected from at least one of N, N-dimethylacetamide, N-methylpyrrolidone, gamma-butyrolactone and methoxypropyl acetate, and 1, 1, 1, 3, 3-pentafluorobutane, wherein the weight ratio of the 1, 1, 1, 3, 3-pentafluoropropane to the 1, 1, 1, 3, 3-pentafluorobutane is not less than 60/40, (1, 1, 1, 3, 3-pentafluoropropane +1, 1, 1, 3, 3-pentafluorobutane)/the compatilizer is 95/5-60/40.

2. A process for producing a rigid polyurethane foam, which comprises mixing an isocyanate component and a polyol composition, foaming and curing the mixture to form a rigid polyurethane foam,

the polyol composition at least comprises a polyol compound, a foaming agent, a foam stabilizer and a catalyst, wherein the foaming agent mainly comprises 1, 1, 1, 3, 3-pentafluoropropane and at least one compatilizer selected from N, N-dimethylacetamide, N-methylpyrrolidone, gamma-butyrolactone and methoxypropyl acetate and 1, 1, 1, 3, 3-pentafluorobutane, and the weight ratio of the 1, 1, 1, 3, 3-pentafluoropropane to the 1, 1, 1, 3, 3-pentafluorobutane is not less than 60/40, and the weight ratio of the 1, 1, 1, 3, 3-pentafluoropropane to the 1, 1, 1, 3, 3-pentafluorobutane to the compatilizer is 95/5-60/40.

3. The polyol composition for rigid polyurethane foam according to claim 1, wherein the polyol compound is at least one selected from the group consisting of a tertiary amine group-containing polyol compound, an aliphatic polyol and an aromatic polyol.

4. The polyol composition for rigid polyurethane foam according to claim 3, wherein the polyol compound having a tertiary amino group is a polyfunctional polyol compound obtained by ring-opening addition polymerization of an alkylene oxide with a primary or secondary amine as an initiator.

5. The polyol composition for rigid polyurethane foam according to claim 3, wherein the aliphatic polyol is a polyfunctional oligomer obtained by ring-opening addition polymerization of an alkylene oxide to an aliphatic polyfunctional active hydrogen compound using a polyol compound as an initiator.

6. The polyol composition for rigid polyurethane foam according to claim 3, wherein the aromatic polyol is a polyol compound obtained by adding an alkylene oxide to a polyfunctional active hydrogen compound having an aromatic ring in the molecule or a polyol compound which is an ester of an aromatic polycarboxylic acid and a polyol.

7. The polyol composition for rigid polyurethane foams according to claim 3, wherein the aliphatic polyol is an alicyclic polyol and is a polyfunctional oligomer obtained by ring-opening addition polymerization of an alkylene oxide to an alicyclic polyfunctional active hydrogen compound using a polyol compound as an initiator.