KR101578059B1 - Foamed hard polyurethane foam based on phenolic resin without using acid hardener and method for producing it - Google Patents

Abstract

The present invention has a problem that existing phenol foam is thermally stable at high temperature but is weak in strength and is easily broken and has poor heat insulation property and existing rigid polyurethane foam is excellent in heat insulation property and strength, , The phenolic resin-based polyurethane foam is synthesized and the disadvantages of the two materials are complemented. Unlike the previous studies, the phenolic resin-based hardness To a polyurethane foam.

Description

TECHNICAL FIELD The present invention relates to a hard polyurethane foam based on a phenolic resin foamed without using an acid hardening agent and a method for producing the same. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a hard polyurethane foam,

The present invention has a problem that existing phenol foam is thermally stable at high temperature but is weak in strength and is easily broken and has poor heat insulation property and existing rigid polyurethane foam is excellent in heat insulation property and strength, The present inventors have developed a polyurethane foam based on a phenol resin to compensate for the disadvantages of the two materials. Further, unlike the existing studies, Based rigid polyurethane foam and a method for producing the same.

Polymer materials widely used in everyday life have a large part in substitution of metal materials and inorganic materials such as airplanes, vehicles, trains, architectural structural materials, interior materials, and life products based on the advantages of excellent processability, light weight and economical efficiency. However, due to the nature of the polymer material, it is weak to low heat and flame, and there is a disadvantage that toxic gas and a large amount of smoke are generated when the reaction is fatal to the human body.

The resulting smoke has the disadvantage of losing the visibility and direction of the person, lengthening the exposure time to the toxic gas and consequently losing the ability to evacuate.

In addition, although a heat insulating material containing a halogen or phosphorus flame retardant added to a polymer material is used, even when various flame retardants such as halogen or phosphorus are added, the resin itself is weak to heat and is plastic, so there is a limit in thermal stability. The use of flame retardants is avoided. Furthermore, since phosphorus compounds are often water-soluble, they elute at the time of disposal to cause environmental pollution.

As the use of polymer materials increases, studies for improving the thermal stability of polymeric materials have been actively conducted. Recently, researches on heat-resistant insulation materials have been carried out without using halogen or phosphorus flame retardant materials, The development of a heat insulating material using a phenolic resin molding material having a structure has been spreading.

The phenol resin has a very high heat resistance and flame retardancy without adding a flame retardant which has a large environmental load in the prior art, because it has a multifilament type having a large number of reactive bonding water and easily forms carbonization and flame shielding film as a whole .

In order to meet such demand, researches are being carried out to utilize phenol resin as a flame retardant resin material both at home and abroad. In particular, since phenol resin does not generate harmful gas such as halogen compound during combustion and has excellent heat stability, researches of heat insulating material using phenol resin are concentrated around the world.

Regarding this, in the past, Korean Patent Laid-Open No. 10-2009-0090298 (published on Aug. 25, 2009) 'Method for producing rigid polyurethane foam and rigid polyurethane foam'; Korean Unexamined Patent Publication No. 10-2010-0075414 (Published Date 2010.07.02) 'Composition for preparing rigid polyurethane foam and rigid polyurethane foam'; Korean Registered Patent No. 10-0568213 (Registered on March 30, 2006) 'Method of producing rigid polyurethane foam'; Korean Patent Laid-Open No. 10-2006-0135528 (Publication date 2006.12.29) 'Polyisocyanate component and rigid polyurethane foam'; Korean Patent Laid-Open No. 10-2011-0139273 (published date December 28, 2011) 'Method of producing rigid polyurethane foam'; Korean Patent No. 10-1177751 (registered date Aug. 22, 2012) discloses a catalyst composition for preparing rigid polyurethane foam and isocyanurate-modified rigid polyurethane foam and a raw material composition using the same.

However, existing phenol foam foamed by adding an acid hardener to phenol resin is easily broken, has a weak strength and low heat insulating property. In order to compensate for this disadvantage, isocyanate and acid curing agent are added to phenol resin to foam However, there is still a disadvantage that the metal is corroded by shortening the lifetime of the equipment because the acid hardening agent is added.

Accordingly, the present inventors have studied to solve the thermal stability problem of a polyurethane foam foamed using a conventional polyether and ester resin, and have found that the resin itself reacts with a thermosetting resin having a resonance structure with an isocyanate, The isocyanate prepolymer was used for confirming the presence / absence and establishing the foaming conditions, and confirming the physical properties thereof, thereby completing the present invention.

Korean Patent Publication No. 10-2009-0090298 (Published Date 2009.08.25) Korean Patent Publication No. 10-2010-0075414 (Published Date 2010.07.02) Korean Registered Patent No. 10-0568213 (registered on March 30, 2006) Korean Patent Laid-Open No. 10-2006-0135528 (Publication date 2006.12.29) Korean Patent Publication No. 10-2011-0139273 (published date December 28, 2011) Korean Registered Patent No. 10-1177751 (registered on August 22, 2012)

In order to solve the above-mentioned problems, the present invention has the disadvantages that the phenol foam which is conventionally used is stable at a high temperature, is weak in mechanical strength and is easily broken and has poor heat insulation property, and the acid hardening agent corrodes metals, and,

Although conventional rigid polyurethane foams have high mechanical strength and heat insulation properties, they have a high thermal stability by foaming polyurethane foam using a phenolic resin having a resonance structure in order to complement the disadvantage of rapid decomposition at 200 ° C or higher, In addition to solving the problems of the prior art by complementing the mechanical strength which is a disadvantage of conventional phenol foam due to secondary bonding and crosslinking between functional groups, unlike the conventionally studied phenol resin-based polyurethane foam, an acid hardener is not used, And it is an object of the present invention to provide a rigid polyurethane foam capable of solving the problem of metal corrosion caused by a curing agent and a method for producing the same.

In order to achieve the above objects,

A hard polyurethane foam based on a phenolic resin foam prepared by mixing and foaming an isocyanate prepolymer without using an acid hardening agent is provided.

As a method for producing the rigid polyurethane foam,

The mixture of 5 to 20 wt% of polyol and 80 to 95 wt% of PMDI (4,4-diphenylmethane diisocyanate) was stirred at a temperature of 65 to 75 ° C at a temperature of 150 ~ The mixture is heated and stirred at 250 rpm for 1.5 to 2.5 hours to obtain a dark brown liquid product, and a step of preparing an isocyanate prepolymer,

100 parts by weight of the isocyanate prepolymer is added to 100 parts by weight of the phenol resin, and the mixture is stirred at 2500 to 3500 rpm to synthesize a hard polyurethane foam.

The hard polyurethane foam based on the phenol resin according to the present invention can solve the corrosion problem of the prior art by not using an acid hardener in the phenol foam and can provide a phenol resin having improved heat stability at a higher temperature than the conventional polyurethane foam Based polyurethane foam can be provided.

1 is a photograph showing the shape of a foam after combustion.
2 is a thermogravimetric analysis graph of phenol resin foam according to NCO% of prepolymer.
Fig. 3 is a graph comparing urethane foam synthesized using a polyester polyol with foam synthesized using a phenol resin. Fig.

Hereinafter, the technical contents of the above description will be described in detail.

Conventional rigid polyurethane foam is a material having excellent heat insulation, chemical resistance and high compressive strength, but has a problem of being rapidly decomposed at 200 ° C or higher. Conventional phenol foam has high heat resistance, but is weak in strength and is easily broken. There is a disadvantage that the product is corroded by adding a topic. To overcome this problem, studies have been carried out to add isocyanates to existing phenolic foams that mix phenolic resins and acid curing agents.

However, in order to solve this problem, in the present invention, phenol resin-based rigid polyurethane foam is used by using only phenol resin and isocyanate without using an acid hardening agent, because acid hardening agent has a fatal disadvantage of shortening the life of equipment by corroding metals. Were synthesized.

That is, the present invention relates to a phenol resin-based rigid polyurethane foam which does not use an acid-curing agent,

The rigid polyurethane foam comprises a phenolic resin;

Isocyanate prepolymer; < / RTI >

And the phenol resin is a Resol type phenol resin.

Phenol resin is a thermosetting resin produced by reacting phenol and formaldehyde, and there are Novolac type and Resol type. The novolak type is obtained by reacting under an acidic catalyst. When heated to a solid state at room temperature, it melts but does not cure. A cross-linking agent is added and cured by heating.

The resole type is obtained by reacting under an alkaline catalyst and is cured when heated. Since a crosslinking agent is not required, a cured resin free from ammonia generation can be obtained.

The following general formula (1) is a general structure of a resol type phenolic resin.

The isocyanate prepolymer is prepared by stirring 5 to 20 wt% of polyol and 80 to 95 wt% of PMDI (4,4-diphenylmethane diisocyanate) at a temperature of 65 to 75 ° C Under conditions of 150 to 250 rpm for 1.5 to 2.5 hours, and the isocyanate prepolymer is characterized by an NCO content of 5 to 30 wt%.

In the case of rigid urethane foam produced by reacting NCO% with a low prepolymer, the compressive strength increased and did not significantly affect the decomposition rate of the polyurethane foam over time. In the case of a polyurethane foam using a phenol resin, It was confirmed that the urethane foam had a high thermal stability in the range of 300 to 600 캜 than that of the urethane foam.

The process for preparing a rigid polyurethane foam based on a phenolic resin foamed without using an acid hardener according to the present invention comprises stirring 5 to 20 wt% of the polyol and 80 to 95 wt% of PMDI (4,4-diphenylmethane diisocyanate) The mixture is heated and stirred at a temperature of 65 to 75 ° C at a temperature of 150 to 250 rpm for 1.5 to 2.5 hours to obtain a dark brown liquid product. Step,

100 parts by weight of the isocyanate prepolymer is added to 100 parts by weight of the phenol resin, and the mixture is stirred at 2500 to 3500 rpm to synthesize a hard polyurethane foam.

When the isocyanate prepolymer is added in an amount of less than 100 parts by weight based on 100 parts by weight of the phenol resin, there is a problem of leakage of the unreacted phenol resin. When the isocyanate prepolymer is used in an amount of more than 150 parts by weight, The use amount of the isocyanate prepolymer is preferably limited within a range of 100 parts by weight to 150 parts by weight based on 100 parts by weight of the phenol resin. More preferably, 110 parts by weight is used.

Hereinafter, the details of the manufacturing steps of the rigid polyurethane foam according to the present invention will be described.

[ Prepolymer ( Prepolymer ) Production]

In a four-necked flask equipped with a thermocouple thermometer and a mechanical stirrer, PMDI (4,4-diphenylmethane diisocyante), adipic acid having a hydroxyl value of 220 and a functional group of 3, diethylene glycol and trimethylolpropane-based polyol were placed, Followed by stirring to prepare a prepolymer having 10 wt% to 30 wt% of NCO%, respectively.

As the reaction proceeds, the temperature rises. At the point where the temperature does not rise any further, the four-necked flask is transferred to a mantle and heated / stirred at 70 ° C and a stirring speed of 200 RPM for 2 hours to obtain a dark brown liquid product.

The compounding ratio for synthesizing the prepolymer is shown in Table 1 below.

Materials Polyol (g) The PMI (g) Contents NCO% = 10 311.51 688.49 NCO% = 15 239.07 760.93 NCO% = 20 166.62 833.38 NCO% = 24 108.67 891.33 NCO% = 28 50.71 949.29 NCO% = 30 21.73 978.27

[Polyurethane foam synthesis]

In order to investigate the effect of the prepolymer on the polyurethane foam using the phenol resin, 10 wt%, 15 wt%, 20 wt%, 24 wt%, 28 wt% and 30 wt% of NCO% were mixed with the phenol resin, For comparison with rigid polyurethane foams used in the past, thermal stability and mechanical properties were compared by mixing and foaming with polyether resin.

Table 2 below shows stirring speed, stirring time, stirring ratio of prepolymer and polyol, and presence / absence of foaming.

Prepolymer
Kinds Phenol (g) NCO index Mixing time (s) Stirring speed
(rpm) Foaming oil
PMDI
100 110 120 3000 radish 30wt%
Prepolymer 100 110 45 3000 U 28wt%
Prepolymer 100 110 45 3000 U 24wt%
Prepolymer 100 110 20 3000 U 20wt%
Prepolymer 100 110 20 3000 U 15wt%
Prepolymer 100 110 20 3000 U 10wt%
Prepolymer 100 110 20 3000 U

In Table 2, the presence or absence of foaming was judged to form a hard foam.

The phenol resin was placed in a 1L PE cup and 28 wt% prepolymer was added at a weight ratio of 110. The resulting mixture was stirred at 3000 RPM to give a hard urethane foam, which was designated P-1. To evaluate the compressive strength, 30 mm × 30 mm × 30 mm The densities were measured by cutting the specimens and the compressive strength was measured by ASTM D1621 using a universal testing machine (UTM).

The hardness was measured by using GS-701N manufactured by TECLOCK Co. The surface was measured five times and the average value was obtained. The measured density, hardness and compressive strength are shown in Table 3 below.

Psalter density
(Kg / m3)
Compressive strength
(Kgf / cm2)

Compressive strength / density
(Kgf * m / Kg)
Hardness
(g)
P-1
271.03 49.7 1834 795.6

The phenol resin was placed in a 1 L PE cup and a 24 wt% prepolymer was administered at a weight ratio of 110. The resulting mixture was stirred at 3000 RPM to give the resulting hard urethane foam as P-2,

To determine the compressive strength, the sample was cut into 30 mm × 30 mm × 30 mm and the density was measured. The compressive strength was measured by UTM (universal testing machine) using ASTM D1621.

The hardness was measured by using GS-701N manufactured by TECLOCK Co. The surface was measured five times and the average value was obtained. The measured density, hardness and compressive strength are shown in Table 4 below.

Psalter density
(Kg / m3) Compressive strength
(Kgf / cm2)
Compressive strength / density
(Kgf * m / Kg) Hardness
(g) P-2 223.67 85.9 3840 829.8

The phenol resin was placed in a 1 L PE cup and a 20 wt% prepolymer was dispensed at a weight ratio of 110. The mixture was stirred at 3000 RPM to assign the resulting hard urethane foam to P-3,

To determine the compressive strength, the sample was cut into 30 mm × 30 mm × 30 mm and the density was measured. The compressive strength was measured by UTM (universal testing machine) using ASTM D1621.

The hardness was measured by using GS-701N manufactured by TECLOCK Co. The surface was measured five times and the average value was obtained. The measured density, hardness and compressive strength are shown in Table 5 below.

Psalter density
(Kg / m3) Compressive strength
(Kgf / cm2)
Compressive strength / density
(Kgf * m / Kg) Hardness
(g) P-3 236.13 101.6 4303 835

The phenolic resin was placed in a 1 L PE cup and the 10 wt% prepolymer was administered at a weight ratio of 110. The mixture was stirred at 3000 RPM to give the resulting hard urethane foam as P-3,

To determine the compressive strength, the sample was cut into 30 mm × 30 mm × 30 mm and the density was measured. The compressive strength was measured by UTM (universal testing machine) using ASTM D1621.

The hardness was measured by using GS-701N manufactured by TECLOCK Co. The surface was measured five times and the average value was obtained. The measured density, hardness and compressive strength are shown in Table 6 below.

Psalter density
(Kg / m3) Compressive strength
(Kgf / cm2)
Compressive strength / density
(Kgf * m / Kg) Hardness
(g) P-4 240.2 105.3 4384 837

In order to establish the foam stabilization conditions of polyurethane foam, a liquid prepolymer was prepared by using 4,4-diphenylmethane diisocyante (PMDI) and polyol, and the phenolic resin-based rigid polyurethane foam was synthesized by reacting with a phenol resin. Urethane foam.

[Comparative Example 1]

The polyester polyol was placed in a 1 L PE cup and 28% prepolymer was added at a weight ratio of 110. The mixture was stirred at 3000 RPM to give the resulting rigid urethane foam as R-1,

To determine the compressive strength, the sample was cut into 30 mm × 30 mm × 30 mm and the density was measured. The compressive strength was measured by UTM (universal testing machine) using ASTM D1621.

The hardness was measured by using GS-701N manufactured by TECLOCK Co. The surface was measured five times and the average value was obtained. The measured density, hardness and compressive strength are shown in Table 7 below.

Psalter density
(Kg / m3) Compressive strength
(Kgf / cm2)
Compressive strength / density
(Kgf * m / Kg) Hardness
(g) R-1 221.11 44.3 2004 778.5

[Comparative Example 2]

The polyester polyol was placed in a 1 L PE cup and the 24% prepolymer was administered at a weight ratio of 110. The mixture was stirred at 3000 RPM to give the resulting hard urethane foam as R-2,

To determine the compressive strength, the sample was cut into 30 mm × 30 mm × 30 mm and the density was measured. The compressive strength was measured by UTM (universal testing machine) using ASTM D1621.

The hardness was measured by using GS-701N manufactured by TECLOCK Co. The surface was measured five times and the average value was obtained. The measured density, hardness and compressive strength are shown in Table 8 below.

Psalter density
(Kg / m3) Compressive strength
(Kgf / cm2)
Compressive strength / density
(Kgf * m / Kg) Hardness
(g) R-2 233.86 49.6 2121 787.1

[Comparative Example 3]

The polyester polyol was placed in a 1 L PE cup and the 20% prepolymer was administered at a weight ratio of 110. The mixture was stirred at 3000 RPM to give the resulting rigid urethane foam as R-3,

To determine the compressive strength, the sample was cut into 30 mm × 30 mm × 30 mm and the density was measured. The compressive strength was measured by UTM (universal testing machine) using ASTM D1621.

The hardness was measured by using GS-701N manufactured by TECLOCK Co. The surface was measured five times and the average value was obtained. The measured density, hardness and compressive strength are shown in Table 9 below.

Psalter density
(Kg / m3) Compressive strength
(Kgf / cm2)
Compressive strength / density
(Kgf * m / Kg) Hardness
(g) R-3 273.95 61.9 2260 795.6

Overall, as the NCO% of the isocyanate prepolymer (isocyanate prepolymer) was lowered, the hardness and the compressive strength tended to increase, and the hardness and compressive strength were not lower than those of the conventional polyurethane foam.

[Test Example 1]

Measurement of combustion time of foam using phenolic resin

In order to measure the burning distance and burning time of the foam using phenolic resin, it was cut into a size of 50mm × 20mm × 5mm and the length and time of burning were measured by placing the end of the specimen on the flame for 15 seconds. The burning time was measured after the end of the heating, and was measured as the time when the flame on the surface of the urethane foam disappeared.

The combustion distance was measured as the distance after the end of combustion, the used flame was blue and the flame length was 50 mm.

The distance between the specimen and the test specimen was 50 mm. The specimens of P-1, R-1, P-2 and R-2 were used for the test. FIG. 1 shows the shape of the foam after combustion, and Table 10 below shows the combustion time and the combustion distance.

sample Burning time (s) Combustion distance (mm) Morphological transformation P-1 24 or more - ○ P-2 23 or more - ○ R-1 1.59 10 × R-2 1.54 0.8 ×

Both R-1 and R-2 were burned to the end of the specimen 20 to 25 seconds after the end of heating, and the burning time and burning distance could not be measured.

In case of P-1 and P-2 using phenolic resin, the combustion time was between 1.2 and 1.9 seconds, and the combustion distance was 10 mm × 2 mm. The combustion time and combustion distance were shorter than those of urethane foam using polyester polyol.

Pyrolysis Behavior of Foam Using Phenolic Resin

Thermogravimetric analyzer (TGA) was used to measure the thermal stability of the foam using phenolic resin. The difference in the heat resistance according to the content of the measured prepolymer was not large, and the thermal stability of the hard urethane foam added with the phenol resin was increased compared with the conventional polyurethane foam.

2 is a thermogravimetric analysis of phenol resin foam according to NCO% of prepolymer. 3 is a graph comparing urethane foam synthesized using a polyester polyol with foam synthesized using a phenol resin.

The TGA curve analysis of the phenolic foam foam showed no significant difference in heat resistance between NCO% and 300 ℃ ~ 600 ℃. The foamed foam with phenol resin was more stable than the polyester polyol The heat resistance in the range of ℃ ~ 500 ℃ showed a great difference.

The rigid polyurethane foam according to the present invention is superior in thermal stability at a higher temperature than conventional polyurethane foam, and is not industrially applicable because corrosion is not caused by the use of an acid hardening agent.

Claims (5)

delete delete delete delete The mixture of 5 to 20 wt% of polyol and 80 to 95 wt% of PMDI (4,4-diphenylmethane diisocyanate) was stirred at a temperature of 65 to 75 ° C at a temperature of 150 ~ The mixture is heated and stirred at 250 rpm for 1.5 to 2.5 hours to obtain a dark brown liquid product, and a step of preparing an isocyanate prepolymer,
Wherein the isocyanate prepolymer is used in an amount of 100 parts by weight to 150 parts by weight based on 100 parts by weight of the phenolic resin and stirred at 2500 to 3500 rpm to synthesize a hard polyurethane foam. By weight of the polyurethane foam.

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