WO2015102373A1 - Phenolic resin-based rigid polyurethane foam foamed by using no acid curing agents and preparation method therefor - Google Patents

Abstract

The present invention relates to a phenolic resin-based rigid polyurethane foam in which a known phenolic foam has the problem of being thermally stable at a high temperature but easily breaking due to low strength and having inferior thermal insulation and in which a known rigid polyurethane foam has the problem of having remarkable thermal insulation and strength but rapidly degrading at 200°C or higher, and thus the shortcomings of the two materials complement each other by synthesizing a phenolic resin-based polyurethane foam, and the corrosion of metals is not caused by not using acid curing agents differently from previously reported research.

Description

Phenolic Resin-based Hard Polyurethane Foam Foamed without Acid Curing Agent and Manufacturing Method Thereof

The present invention is that the conventional phenolic foam is thermally stable at high temperature, but the strength is weak and easily broken and poor insulation, and the conventional rigid polyurethane foam has a problem of being rapidly decomposed at 200 ℃ or more, although excellent thermal insulation and strength In view of this, phenolic resin-based polyurethane foams can be synthesized to compensate for the shortcomings of the two materials and, unlike previous published studies, foaming without the use of acid hardeners does not cause corrosion of metals. It relates to a rigid polyurethane foam based and a method for producing the same.

Polymer materials, which are widely used in daily life, take up a large portion of metal materials and inorganic materials such as aircraft, vehicles, trains, building structures and interior materials, and everyday products based on the advantages of excellent processability, light weight, and economic efficiency. However, due to the nature of the polymer material, it is weak to low heat and flame, and has a disadvantage of generating a large amount of toxic gas and smoke when reacting.

The smoke generated has the disadvantage of losing the visibility and direction of the person, lengthening the exposure time to the toxic gas and consequently losing the evacuation capacity.

Insulation materials using halogen or phosphorus flame retardant materials are used in polymer materials. However, even if halogen or phosphorus flame retardants are added, thermal stability is limited because the resin itself is weak and plastic, and the production cost is high when flame retardants are added. The situation is avoiding the use of flame retardant materials. Moreover, since phosphorus compounds are often water-soluble, they are eluted at the time of disposal, causing environmental pollution.

 As the use of polymer materials increases, researches to improve the thermal stability of polymer materials have been actively conducted. Recently, in the study of heat-resistant insulating materials, they do not use halogens or phosphorus-based flame retardants, and are themselves heat-resistant and difficult to burn. The development movement of the heat insulating material using the phenol resin molding material which has a structure is spreading.

Phenolic resins are multifunctional, having a large number of reactive bonds, and are easily carbonized as a whole of the molding material and form a film to block the flame. Therefore, the phenol resin itself has extremely high heat resistance and flame resistance even without adding a flame retardant having a large environmental load. .

In order to meet such demands, research is being conducted to utilize phenol resins as flame retardant resin materials at home and abroad. In particular, phenol resin (phenol resin) does not generate harmful gases such as halogen compounds during combustion and excellent thermal safety has been concentrated around the world research on the insulation material using phenol resin.

In this regard, conventional Republic of Korea Patent Publication No. 10-2009-0090298 (published date 2009.08.25) 'Method for producing a rigid polyurethane foam and rigid polyurethane foam'; Republic of Korea Patent Application Publication No. 10-2010-0075414 (published 2010.07.02) 'composition for producing a rigid polyurethane foam and rigid polyurethane foam'; Republic of Korea Patent Registration 10-0568213 (Registration Date 2006.03.30) 'Method for producing a rigid polyurethane foam'; Republic of Korea Patent Application Publication No. 10-2006-0135528 (published Dec. 29, 2006) 'polyisocyanate component and rigid polyurethane foam'; Republic of Korea Patent Application Publication No. 10-2011-0139273 (published 2011.12.28) 'Method for producing a rigid polyurethane foam'; Republic of Korea Patent Registration 10-1177751 (Registration date 2012.08.22) 'hard polyurethane foam and isocyanurate modified catalyst composition for producing a rigid polyurethane foam and a raw material composition using the same has been disclosed.

However, conventional phenolic foams foamed by adding an acid curing agent to phenolic resins have the disadvantages of being easily brittle, weak in strength, and poor insulators. In addition, foams are foamed by adding isocyanate and acid hardener to phenolic resins. Previous studies have been conducted, but there is still a disadvantage that the acid hardener is added to corrode metals and shorten the life of the equipment.

Accordingly, the present inventors studied to solve the thermal stability problem of the polyurethane foam foamed by using the polyether and ester-based resins used in the prior art, and the resin itself reacts with isocyanate to expand the phenol resin having a thermally stable resonance structure with isocyanate. Isocyanate prepolymer was used to confirm the presence / absence and to establish the foaming conditions, and the present invention was completed by checking the physical properties.

In order to solve the above problems, the present invention has the advantage that the phenolic foam used in the past is stable at high temperature, the mechanical strength is weak and easily broken and poor insulation, acid curing agent corrodes the metal to shorten the life of the equipment and,

In order to supplement the disadvantage that the existing rigid polyurethane foam has high mechanical strength and thermal insulation, but rapidly decomposes at 200 ° C or higher, foaming a polyurethane foam using a phenol resin having a resonance structure ensures high thermal stability, and Not only solves the problems of the prior art by complementing the mechanical strength, which is a disadvantage of the conventional phenolic foams by the secondary bonding and crosslinking between functional groups, but also does not use acid curing agents unlike the phenolic resin-based polyurethane foams studied in the past. It is an object of the present invention to provide a rigid polyurethane foam and a method of manufacturing the same that can solve the problem of corrosion of the metal by the curing agent.

In order to achieve the above object, the present invention is a phenol resin;

Isocyanate prepolymer; to provide a rigid polyurethane foam based phenol resin foamed without using an acid curing agent, prepared by mixing foamed.

And as a manufacturing method of the rigid polyurethane foam,

5 ~ 20wt% of polyol and 80 ~ 95wt% of PMDI (4,4-Diphenylmethane diisocyante) were stirred at 150 ~ 65 ℃ at the temperature of 65 ~ 75 ℃ when the temperature was not increased any more. Isocyanate prepolymer production step of obtaining a dark brown liquid product by heating and stirring at 250rpm for 1.5-2.5 hours,

100 parts by weight to 150 parts by weight of the isocyanate prepolymer is added to 100 parts by weight of the phenol resin and stirred at 2500 to 3500 rpm to provide a method for producing a rigid polyurethane foam comprising the step of synthesizing the rigid polyurethane foam.

The phenolic resin-based rigid polyurethane foam according to the present invention can solve the problem of corrosion of the prior art by not using an acid curing agent in the phenolic foam, and the phenolic resin having improved thermal stability at high temperature than the conventional polyurethane foam. It has the advantage of being able to provide a base polyurethane foam.

1 is a photograph showing the form of the foam after combustion.

2 is a thermogravimetric analysis graph of phenolic resin foam according to NCO% of prepolymer.

Figure 3 is a graph comparing the foam synthesized with a urethane foam synthesized using a polyester polyol and a phenol resin.

Hereinafter, a detailed description of the above technical configuration will be made.

Conventional rigid polyurethane foam is a material having excellent thermal insulation, chemical resistance and high compressive strength, but there is a problem that it is rapidly decomposed above 200 ℃, conventional phenolic foam has a high heat resistance, but the strength is weak and easily broken and hardened when hardened There is a drawback of corroding the product by adding a topic. In order to solve this problem, studies have been made to add isocyanate to a conventional phenolic foam in which a phenol resin and an acid hardener are mixed.

However, acid hardeners have a fatal disadvantage of corroding metals to shorten the life of equipment. In the present invention, phenolic resin-based hard polyurethane foams using phenol resins and isocyanates without using acid hardeners to solve this problem. Was synthesized.

That is, the present invention relates to a phenolic resin-based hard polyurethane foam without using an acid hardener,

The hard polyurethane foam is phenolic resin;

Isocyanate prepolymer; prepared by mixing and foaming.

The phenol resin is characterized in that the resol (phenol) type phenol resin.

Phenolic resins are thermosetting resins formed by reacting phenols and formaldehydes, which are of Novolac type and Resol type. The novolak type is obtained by reacting under an acidic catalyst. At room temperature, it melts when heated to a solid phase but does not cure. It hardens when a crosslinking agent is added and heated.

The resol type is obtained by reacting under an alkaline catalyst and cures when heated. Since a crosslinking agent is unnecessary, the cured resin without ammonia generation can be obtained.

Formula 1 below is a general structure of a resol type phenol resin.

Formula 1

The isocyanate prepolymer is stirred at 5 to 20 wt% of polyol and 80 to 95 wt% of PMDI (4,4-Diphenylmethane diisocyante) to a temperature of 65 to 75 ° C. when the temperature rise no longer occurs as the reaction proceeds. Under the conditions, it is prepared by heating and stirring for 1.5 to 2.5 hours at 150 to 250 rpm, and the isocyanate prepolymer is characterized in that NCO% is 5 to 30 wt%.

Rigid polyurethane foams produced by reacting with low NCO% prepolymers had increased compressive strength and did not significantly affect the rate of decomposition of polyurethane foams over time. Polyurethane foams using phenolic resins It was confirmed that the thermal stability was higher in the 300 ~ 600 ℃ section than the urethane foam.

The manufacturing process of the phenolic resin-based hard polyurethane foam foamed without using the acid curing agent according to the present invention is stirred 5 to 20wt% of the polyol (Polyol) and 80 to 95wt% of PMDI (4,4-Diphenylmethane diisocyante) When the temperature rise is no longer observed as the reaction proceeds by the isocyanate prepolymer (Prepolymer) to obtain a dark brown liquid product by heating and stirring at 150 ~ 250rpm for 1.5-2.5 hours at a temperature condition of 65 ~ 75 ℃ Steps,

100 parts by weight to 150 parts by weight of the isocyanate prepolymer with respect to 100 parts by weight of the phenol resin is prepared by stirring at 2500 to 3500rpm to synthesize a rigid polyurethane foam.

At this time, when the isocyanate prepolymer is added to less than 100 parts by weight with respect to 100 parts by weight of the phenol resin, the problem of outflow of unreacted phenol resin occurs, and when the isocyanate prepolymer is administered in excess of 150 parts by weight, polymerization of the isocyanate prepolymer is caused. Since there is a disadvantage in that the heat resistance is lowered, it is preferable that the amount of the isocyanate prepolymer used is limited to 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, look at the specific content of each step of manufacturing a rigid polyurethane foam according to the present invention.

[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 3, functional group 3, diethylene glycol, and polyol based on trimethylol propane were added at 200 RPM. By stirring, a prepolymer having NCO% of 10 wt% to 30 wt% was prepared.

As the reaction proceeds, the temperature rises, and when the temperature no longer rises, the 4-necked flask is transferred to the 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 blending ratio for synthesizing the prepolymer is shown in Table 1 below.

Table 1

Materials	Polyol (g)	PMDI (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 examine the effect of prepolymer on polyurethane foam using phenolic resin, NCO% mixed 10wt%, 15wt%, 20wt%, 24wt%, 28wt%, 30wt% prepolymer with phenolic resin, The foam was mixed with the polyether resin and foamed for comparison with the conventional rigid polyurethane foam. The thermal stability and mechanical properties were compared.

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

TABLE 2

Prepolymer Type	Phenol (g)	NCO index	Mixing time (s)	Stirring Speed (rpm)	Foamed / No
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 determined to form a rigid foam.

Example 1

Phenol resin was put in 1L PE cup and 28wt% prepolymer was administered at 110 weight ratio, and the rigid urethane foam produced by stirring the mixture at 3000RPM was designated as P-1, respectively, and 30mm × 30mm × 30mm was used to check the compressive strength. The density was measured by cutting the sample, and the compressive strength was measured by ASTM D1621 using a universal testing machine (UTM).

Hardness was used by GS-701N of TECLOCK company and the average value was measured by measuring the surface five times. The measured density, hardness and compressive strength are shown in Table 3 below.

TABLE 3

Psalter	Density (Kg / ㎥)	Compressive strength (Kgf / ㎠)	Compressive Strength / Density (Kgf * m / Kg)	Hardness (g)
P-1	271.03	49.7	1834	795.6

Example 2

Phenol resin was placed in a 1 L PE cup, and 24 wt% prepolymer was administered at a weight ratio of 110. The mixture was agitated at 3000 RPM, and the resulting rigid urethane foam was designated as P-2.

In order to determine the compressive strength, the density was measured by cutting the sample into 30mm × 30mm × 30mm, and the compressive strength was measured by ASTM D1621 using a universal testing machine (UTM).

Hardness was used by GS-701N of TECLOCK company and the average value was measured by measuring the surface five times. The measured density, hardness and compressive strength are shown in Table 4 below.

Table 4

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

Example 3

Phenol resin was placed in a 1 L PE cup, and a 20 wt% prepolymer was administered at a weight ratio of 110. The mixture was agitated at 3000 RPM, and the resulting rigid urethane foam was designated P-3, respectively.

In order to determine the compressive strength, the density was measured by cutting the sample into 30mm × 30mm × 30mm, and the compressive strength was measured by ASTM D1621 using a universal testing machine (UTM).

Hardness was used by GS-701N of TECLOCK company and the average value was measured by measuring the surface five times. The measured density, hardness and compressive strength are shown in Table 5 below.

Table 5

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

Example 4

Phenol resin was placed in a 1 L PE cup and 10 wt% prepolymer was administered at a weight ratio of 110. The mixture was agitated at 3000 RPM, and the resulting rigid urethane foam was designated as P-3.

In order to determine the compressive strength, the density was measured by cutting the sample into 30mm × 30mm × 30mm, and the compressive strength was measured by ASTM D1621 using a universal testing machine (UTM).

Hardness was used by GS-701N of TECLOCK company and the average value was measured by measuring the surface five times. The measured density, hardness and compressive strength are shown in Table 6 below.

Table 6

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

In order to establish the foaming stability condition of polyurethane foam, a liquid prepolymer was prepared using PMDI (4,4-Diphenylmethane diisocyante) and Polyol, and then reacted with phenol resin to synthesize a phenol resin-based rigid polyurethane foam, and then Compared with urethane foam.

Comparative Example 1

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

In order to determine the compressive strength, the density was measured by cutting the sample into 30mm × 30mm × 30mm, and the compressive strength was measured by ASTM D1621 using a universal testing machine (UTM).

Hardness was used by GS-701N of TECLOCK company and the average value was measured by measuring the surface five times. The measured density, hardness and compressive strength are shown in Table 7 below.

TABLE 7

Psalter	Density (Kg / ㎥)	Compressive strength (Kgf / ㎠)	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 24% prepolymer was administered at a weight ratio of 110. The mixture was stirred at 3000 RPM, and the resulting rigid urethane foam was designated as R-2.

In order to determine the compressive strength, the density was measured by cutting the sample into 30mm × 30mm × 30mm, and the compressive strength was measured by ASTM D1621 using a universal testing machine (UTM).

Hardness was used by GS-701N of TECLOCK company and the average value was measured by measuring the surface five times. The measured density, hardness and compressive strength are shown in Table 8 below.

Table 8

Psalter	Density (Kg / ㎥)	Compressive strength (Kgf / ㎠)	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 20% prepolymer was administered at a weight ratio of 110. The mixture was agitated at 3000 RPM, and the resulting rigid urethane foam was designated as R-3, respectively.

In order to determine the compressive strength, the density was measured by cutting the sample into 30mm × 30mm × 30mm, and the compressive strength was measured by ASTM D1621 using a universal testing machine (UTM).

Hardness was used by GS-701N of TECLOCK company and the average value was measured by measuring the surface five times. The measured density, hardness and compressive strength are shown in Table 9 below.

Table 9

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

[Comparative Example 4]

In order to compare the heat resistance of the sample P-2 of Example 2 and the sample R-2 of the comparative example 2, it cut into 20 mm x 20 mm x 20 mm, and measured and compared the heat resistance using the electric furnace.

The internal temperature of the electric furnace was increased by 100 ° C. from 100 ° C. to 800 ° C. and stored for 1 hour to measure the residual amount.

Overall, as the NCO% of the isocyanate prepolymer (isocyanate prepolymer) is lower, the hardness and the compressive strength tend to increase, and the hardness and the compressive strength are not lower than those of the conventional polyurethane foam.

In addition, the weight loss of the existing polyurethane foam up to 200 ℃ is low, but the heat resistance of the phenolic resin-based polyurethane foam was much better than 200 ℃. In particular, the residual amount of polyurethane foam at 800 ℃ was 0, but the residual amount of the phenol resin-based polyurethane foam reaches about 30%, it can be seen that the heat resistance is very excellent.

Overall, as the NCO% of the isocyanate prepolymer (isocyanate prepolymer) is lower, the hardness and the compressive strength tend to increase, and the hardness and the compressive strength are 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 the burning time of the foam using phenolic resin, the cutting was carried out to a size of 50mm × 20mm × 5mm, and the distance and time of burning the flame by applying the tip of the specimen for 15 seconds were measured. The combustion time was measured after the heating was completed, and was measured when the flame on the surface of the urethane foam disappeared.

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

The distance from the specimen was maintained at 50mm from the tip of the specimen, and the average of five specimens of P-1 and R-1, P-2 and R-2 was used for the test. Figure 1 shows the form of the foam after combustion, Table 10 below shows the combustion time and combustion distance.

Table 10

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

In case of R-1 and R-2, after 20 ~ 25 seconds elapsed after heating, it was burned to the end of the specimen, and the combustion time and combustion distance could not be measured.

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

Pyrolysis Behavior of Foam Using Phenolic Resin

The thermogravimetric analyzer (TGA) was used to measure the thermal stability of foams using phenolic resins. The difference in the heat resistance according to the content of the measured prepolymer was not large, and it can be seen that the thermal stability of the rigid urethane foam to which the phenolic resin was added is increased compared to the conventional polyurethane foam.

2 is a thermal gravimetric graph of the phenol resin foam according to the NCO% of the prepolymer (Prepolymer). 3 is a graph comparing urethane foams synthesized using a polyester polyol and foams synthesized using a phenol resin.

TGA curve analysis of phenolic resin foam showed little difference in heat resistance in NCO%, and the heat resistance at 300 ℃ ~ 600 ℃ was more stable than phenolic resin than that of polyester polyol. Heat resistance in the range of ℃ ~ 500 ℃ showed a big difference.

Rigid polyurethane foam according to the present invention is excellent in thermal stability at high temperatures than conventional polyurethane foam, and does not use an acid hardener does not cause corrosion is large industrial applicability.

Claims (6)

1. Phenolic resin;

   Isocyanate prepolymer; phenolic resin-based rigid polyurethane foam foamed without using an acid curing agent, characterized in that prepared by mixing and foaming.
2. The method according to claim 1,

   Phenolic resin is a rigid polyurethane foam based on phenolic resin foamed without using an acid curing agent, characterized in that it is a resol type phenolic resin.
3. The method according to claim 1,

   A phenolic resin-based rigid polyurethane foam characterized by the use of water in a resol-type phenolic resin as a blowing agent.
4. The method according to claim 1,

   Isocyanate prepolymer is a rigid polyurethane foam based on phenol resin foamed without using an acid curing agent, characterized in that the NCO% is 5 ~ 30wt%.
5. The method according to claim 1,

   Isocyanate prepolymer is a mixture of 5 ~ 20wt% of polyol and 80 ~ 95wt% of PMDI (4,4-Diphenylmethane diisocyante) by stirring the temperature condition of 65 ~ 75 ℃ when the temperature rise no longer occurs as the reaction proceeds Phenolic resin-based rigid polyurethane foam foamed without using an acid curing agent, characterized in that it is prepared by heating and stirring at 150-250 rpm for 1.5-2.5 hours.
6. 5 ~ 20wt% of polyol and 80 ~ 95wt% of PMDI (4,4-Diphenylmethane diisocyante) were stirred at 150 ~ 65 ℃ at the temperature of 65 ~ 75 ℃ when the temperature was not increased any more. Isocyanate prepolymer production step of obtaining a dark brown liquid product by heating and stirring at 250rpm for 1.5-2.5 hours,

   100 parts by weight to 150 parts by weight of the isocyanate prepolymer was added to 100 parts by weight of the phenol resin, followed by stirring at 2500 to 3500 rpm to synthesize a rigid polyurethane foam. Rigid polyurethane foam production method.

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