KR100947247B1 - Polyurethane foam compositions for pipes insulation and manufacturing method thereof and foam therefrom - Google Patents

Abstract

PURPOSE: A polyurethane foam compositions for pipe insulation is provided to maintain an insulation property at 160-200 °C for 10 years, and to ensure excellent mechanical strength and fire retardant characteristic while not degrading cracking, carbonization, and adhesive force. CONSTITUTION: A polyurethane foam compositions for pipe insulation comprises mixed polyol, isocyanate, catalyst, foaming agent and surfactant. The mixed polyol comprises, based on isocyanate 100.0 parts by weight, (a) polyester polyol 50-100.0 parts by weight, (b) phthalate polyestersether polyol 10-40 parts by weight obtained by reacting polyester including phthalate and/or adipic acid with propylene oxide and ethylene oxide, (c) carprolactone polyether polyol 5-20 parts by weight obtained by reacting alkylene oxide with caprolactone, (d) glycol polyether polyol 10-30 parts by weight obtained by reacting styrene oxide and butylene oxide with glycol, and (e) bisphenol A polyether polyol 5-15 parts by weight obtained by reacting styrene oxide and butylene oxide with bisphenol A.

Description

Polyurethane foam composition for heat insulation of pipe having heat resistance, foaming method using the same and foam thereof therein {POLYURETHANE FOAM COMPOSITIONS FOR PIPES INSULATION AND MANUFACTURING METHOD THEREOF AND FOAM THEREFROM}

The present invention relates to a polyurethane foam composition for heat insulating pipe having a heat resistance, a foaming method using the same, and a foam thereof, and more particularly, by mixing a polyester polyol and a polyether polyol with enhanced heat resistance, By reacting and foaming with phenylmethane diisocyanate, the polyurethane foam composition for pipe insulation and foaming method using the same are significantly improved in heat resistance of polyurethane and having excellent heat resistance even at high temperatures of 160 to 200 ° C. It is about.

Polyurethane resins, which are typical of thermosetting resins, are relatively inexpensive and easy to mold, and their foams are widely used throughout household goods including automobile parts. As a method of manufacturing such a thermosetting polyurethane foam, the chemical foaming method using thermally decomposable foaming agents, such as azodicarbonamide, is known by Unexamined-Japanese-Patent No. 7-157588.

In general, polyurethane foam is the most excellent heat insulating material among the oil and inorganic heat insulating materials, which requires high heat insulating properties and is frequently used for low temperature applications such as refrigerators, freezing containers, and low temperature warehouses. This is because polyurethane foam is composed of independent bubbles, excellent heat insulation, and can control low density foam by adjusting the amount and type of blowing agent. However, polyurethane resins are flammable and have a large disadvantage of poor heat resistance.

Most of these hard polyurethane foams currently used are used at a temperature of -190 to 120 ° C. When the temperature reaches 120 ° C or higher, thermal decomposition occurs due to high temperature, resulting in charring of the foam. If the foam is damaged, the double insulation tube made of polyurethane as a heat insulating material will lose its heat insulating performance.

Therefore, in the case of the insulation pipe used at such a high temperature, in order to use at a temperature of 120 ° C. or more, a material such as calcium silicate, mineral wool, glass fiber, silica, foam glass, etc. is usually wrapped around the pipe to fix the insulation or glass wool or It is manufactured in the form of triple insulation tube that foams polyurethane again after primary insulation wrapped with inorganic insulation such as rock wool, silica, pearlite, etc., which increases the manufacturing cost, increases working time and uses heterogeneous materials to integrate the double insulation tube. There is a problem of not taking advantage of the structure.

In addition, as a method of foaming a polyurethane board in such a double heat insulation tube, the spray foaming method and the injection foaming method were conventionally used.

As shown in FIG. 1, the spray foaming method rotates the pipe and sprays the polyurethane foam on the cross section so that the polyurethane foam is formed evenly around the pipe. When foaming occurs, the foam is hardened immediately after foaming. After hardening of the foam, the polyethylene jacket is extruded again to protect the foam.It is a manufacturing method mainly applied in Europe. It has the advantage of being able to calculate the injection-like output with a relatively small working space and a small number of people by working continuously, but this requires fast reaction time. sagging or separating Not only is there a high risk of problems such as spun off or increased insulation thickness, but the surface must be even and the adhesion between the foam and the exterior is weak, unlike the injection method. Although a separate facility for extruding the jacket is required, there is a problem that the quality and price competitiveness are inferior to that of the injection type.

In addition, as shown in Figure 2, the injection-type foaming method is to assemble the inner tube and the exterior in advance and inject the foam composition through the injection hole in order to fill the inside of the reaction in a relatively slow manner in all the current domestic As the production method of related companies, it adopts the production method introduced in Europe without any improvement and produces it by checking the filling state after assembling and foaming individually, so it is effective in reducing defects, but due to the slow curing speed and inappropriate reaction In addition to the risk of unfilled or cracked parts, there is a problem of large density variation in each part, and it requires not only a lot of manpower for assembly but also requires a large work space to make several products at the same time. The disadvantage of requiring hardening time The. Above all, in the manufacture of heat-resistant foam, a rapid reactivity is required to form a polyisocyanurate reaction, but the injection method is inadequate due to the relatively late reactivity.

Accordingly, an object of the present invention is to solve such a conventional problem, whereas the phenomenon that the conventional polyurethane foam is pyrolyzed at a temperature of 120 ℃ or more occurs, heat insulation performance for 10 years even at 160 to 200 ℃ The present invention provides a polyurethane foam composition for pipe insulation and its foam which can be maintained, exhibits excellent mechanical strength without cracking, carbonization, and weakening of adhesion, and has flame retardancy and excellent heat resistance.

In addition, as an optimal foaming method corresponding to the rapid reaction characteristics of the polyurethane foam composition for pipe insulation having heat resistance of the present invention, by using a semi-continuous foaming process, it is possible to reduce the heat loss caused by the spacer, It is to provide a semi-continuous foaming method that can improve the economics and productivity due to the reduction of the reduction and rejection rate.

The polyurethane foam composition for pipe insulation having heat resistance of the present invention for achieving the above object, in the polyurethane foam composition for pipe insulation having heat resistance containing a mixed polyol, isocyanate, catalyst, foaming agent, surfactant, The mixed polyol is (1) polyester polyol, (2) phthalate polyester ether polyol obtained by reacting a propylene oxide and ethylene oxide with a polyester containing at least one of phthalate or adipic acid, (3) Caprolactone polyether polyols obtained by reacting alkylene oxides with caprolactone; (4) glycerol polyether polyols obtained by reacting styrene oxides and butylene oxides with glycols; and (5) bisphenol ae styrene oxides and butylene oxides. Bisphenol-A polyether polyol obtained by reaction Two, wherein the isocyanate is characterized in that it comprises a polymeric 4,4-diphenylmethane diisocyanate.

The mixed polyol is based on 100 parts by weight of the isocyanate, 50 to 100 parts by weight of the polyester polyol, 10 to 40 parts by weight of the phthalate polyester ether polyol, 5 to 20 parts by weight of the caprolactone polyether polyol, and the glypol 10 to 30 parts by weight of a polyether polyol, and 5 to 15 parts by weight of the bisphenol A polyether polyol, and

The polyester polyol is characterized in that the dimethyl phthalate polyester polyol or one of the polyester polyol polycondensed glycol to at least one of phthalic anhydride or polyethylene terephthalate.

In addition, the isocyanate includes a polymeric 4,4-diphenylmethane diisocyanate having a functional group of 2.5 to 3.0, an isocyanate group (NCO) content of 25 to 32, and a viscosity of 150 to 900 centipoise (CPS). The weight ratio of the isocyanate group (NCO) of the isocyanate to the hydroxyl group (-OH) of the mixed polyol is characterized in that 2.5 to 5.0.

The mixed polyol is characterized in that the hydroxyl group (-OH) value is 200 to 600, the catalyst is an amine catalyst, characterized in that it comprises 0.5 to 3.0 parts by weight based on 100 parts by weight of the mixed polyol, The blowing agent is 0.5 to 5 parts by weight of at least one of water (H ₂ O), hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC) or hydrocarbon (HC) based on 100 parts by weight of the mixed polyol or the mixture 0.5 to 2.5 parts by weight of water (H ₂ O) and 10 to 30 parts by weight of at least one of hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC) or hydrocarbon (HC) based on 100 parts by weight of polyol It is characterized by.

In addition, the surfactant is a polysiloxane ether having a molecular weight of 3000 to 7000 g / mol, a viscosity of 100 to 2000 centipoise (CPS), and is 1 to 4 parts by weight based on 100 parts by weight of the mixed polyol.

Next, the foaming method using a polyurethane foam composition for heat insulation having a heat resistance of the present invention for achieving the above object,

In the foaming method using a polyurethane foam composition for pipe insulation having a heat resistance containing a mixed polyol, an isocyanate, a catalyst, a blowing agent, and a surfactant, 50 to 100 parts by weight of polyester polyol, phthalate or 10 to 40 parts by weight of a phthalate polyester ether polyol obtained by reacting a polyester containing at least one of adipic acid with propylene oxide and ethylene oxide, and a caprolactone polyether polyol obtained by reacting an alkylene oxide with caprolactone 5 to 20 parts by weight, 10 to 30 parts by weight of a glycerol polyether polyol obtained by reacting glycol with styrene oxide and butylene oxide, and 2 to 15 parts of bisphenol a polyether polyol obtained by reacting bisphenol a styrene oxide and butylene oxide Parts by weight A reaction solution preparation step of preparing a reaction solution by mixing a mixed polyol, a catalyst, a blowing agent, and a surfactant; An isocyanate preparation step of preparing an isocyanate including the polymeric 4,4-diphenylmethane diisocyanate; And a semi-continuous reaction step of reacting the reaction solution and the isocyanate with a foaming machine at a position to be foamed and foaming.

The semi-continuous reaction step is characterized by adjusting the position to be foamed by moving the foaming machine mixing head in the foaming progress direction, the semi-continuous reaction step by mechanically mixing at a pressure of 1 to 10 bar It is characterized in that it is made of any one of a low pressure type to react or a high pressure type to react by colliding the reaction solution and the isocyanate at a pressure of 50 to 200 bar.

In addition, the isocyanate includes a polymeric 4,4-diphenylmethane diisocyanate having a functional group of 2.5 to 3.0, an isocyanate group (NCO) content of 25 to 32, and a viscosity of 150 to 900 centipoise (CPS). Characterized in that, the weight ratio of the isocyanate group (NCO) of the isocyanate to the hydroxyl group (-OH) of the mixed polyol is 2.5 to 5.0, the mixed polyol is characterized in that the hydroxyl group (-OH) value of 200 to 600 The blowing agent may be 0.5 to 5 parts by weight of at least one of water (H ₂ O), hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC) or hydrocarbon (HC) based on 100 parts by weight of the mixed polyol or 0.5 to 2.5 parts by weight of water (H ₂ O) and at least one of hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC) or hydrocarbon (HC) based on 100 parts by weight of the mixed polyol It comprises a quantity part.

According to the polyurethane foam composition for pipe insulation of the present invention, a method for producing the same, and a foam produced therefrom, a phenomenon in which a conventional polyurethane foam is thermally decomposed at a temperature of 120 ° C. or more occurs, but at 160 to 200 ° C. It can maintain insulation performance for more than a year, and shows excellent mechanical strength without cracking, carbonization, and weakening of adhesive force, and has excellent advantages of flame retardancy.

In addition, as an optimal foaming method corresponding to the rapid reaction characteristics of the polyurethane foam composition for pipe insulation having heat resistance of the present invention, by using a semi-continuous foaming process, it is possible to reduce the heat loss caused by the spacer, There is an advantage that can improve economics and productivity due to the reduction and reduction of defective rate.

Hereinafter, an embodiment of the polyurethane foam composition for pipe insulation having heat resistance according to the present invention will be described.

The polyurethane foam composition for pipe insulation having heat resistance basically comprises a mixed polyol, an isocyanate, a catalyst, a blowing agent, and a surfactant.

First, the mixed polyol will be examined in the polyurethane foam composition for pipe insulation having heat resistance of the present invention.

The mixed polyol is (1) polyester polyol, (2) phthalate polyester ether polyol obtained by reacting a propylene oxide and ethylene oxide with a polyester containing at least one of phthalate or adipic acid, and (3) capro Caprolactone polyether polyols obtained by reacting alkylene oxides with lactones; (4) Glypol polyether polyols obtained by reacting styrene oxides and butylene oxides with glycols; (5) Bisphenol A. Styrene oxides and butylene oxides. It is made by mixing the polyether polyol obtained by the bisphenol.

Herein, the polyester polyol is preferably a dimethyl phthalate polyester polyol or one of polyester polyols polymerized with glycol to at least one of phthalic anhydride or polyethylene terephthalate.

In the mixed polyol composition, dimethyl phthalate, polyethylene terephthalate ester components and ester ether components are mixed in an appropriate ratio so that the mechanical and thermal properties, oil resistance, and chemical resistance of the phthalate-based polyester such as increased crosslinking density and improved heat resistance Excellent urethane is formed, and the caprolactone component plays a role of reinforcing water resistance insufficient in the polyester component.

In addition, the glycol component acts to increase fluidity and adhesion in the process of foam formation, and contributes to lowering the viscosity of the stock solution. The bisphenol A component not only contributes to the improvement of thermal conductivity and uniform formation of foam bubbles, but also to polymerization. Polyester polyol is excellent in thermal stability to improve the curing, and oil resistance has the advantage of relatively excellent, so that the performance is maximized by mixing and using the polyether polyol in an appropriate ratio.

Here, the titration ratio is a number of experiments, the mixed polyol, 50 to 100 parts by weight of the polyester polyol, 10 to 40 parts by weight of the phthalate polyester ether polyol, the caprolactone poly with respect to 100 parts by weight of the isocyanate Mixing 5 to 20 parts by weight of ether polyol, 10 to 30 parts by weight of the glypol polyether polyol, and 5 to 15 parts by weight of the bisphenol A polyether polyol is suitable for maximizing the effects of the present invention such as heat resistance and mechanical strength.

In addition, the mixed polyol preferably has a hydroxyl group (-OH) value of 200 to 600, more preferably 300 to 500. If the hydroxyl group (-OH) value of the mixed polyol is less than 200, formation reaction and crosslinking reaction may not occur, and thus the dimensional stability and mechanical strength of the product may be reduced. If the hydroxyl group (-OH) value is more than 600, the overall physical property value becomes weak. Since there is a problem that the adhesive strength and the foam falls easily, the hydroxy group (-OH) value out of the above-mentioned proper range is a cause of poor product, there is a problem that the productivity is lowered.

Here, the hydroxyl group (-OH) value is a value which represents the hydroxyl group (-OH) in a molecule | numerator as KOH equivalent, and it is a value which can be measured if only a hydroxyl group (-OH) exists in a molecule | numerator. Every polyol (a polyol means a lot of hydroxy groups (-OH)) has a hydroxyl group (-OH) in its molecule, so each has a hydroxy value. Therefore, the hydroxyl group (-OH) value of a substance having a hydroxyl group (-OH) becomes the intrinsic property of the substance.

The following briefly illustrates a method for arithmetically calculating a hydroxyl group (-OH) value.

                    56100 * Hydroxy Functional Group

     PPG Molecular Weight = ---------------------------

                        Hydroxy group (-OH) value

** Molecular weight (mg) of potassium hydroxide (KOH): [K (39.1) + O (16) + H (1)] * 1000 = 56,100

Example) 1. Glycerin (molecular weight = 92)

                           56100 * 3 (hydroxyl functional group of glycerin)

                1829 = ------------------------------------------

        (Hydroxy group (-OH) value) 92 (molecular weight of glycerin)

Example) 2. Propylene glycol (molecular weight = 76)

                        56100 * 2 (hydroxy functional group number of propylene glycol)

          1476 = ----------------------------------------------

  (Hydroxy group (-OH) value) 76 (molecular weight of propylene glycol)

Next, the isocyanate will be examined in the polyurethane foam composition for pipe insulation having heat resistance of the present invention.

The isocyanate consists of polymeric 4,4-diphenylmethane diisocyanate, and may be made by addition of modified diphenylmethane diisocyanate (MDI).

In the isocyanate, the polymeric 4,4-diphenylmethane diisocyanate has a functional group of 2.5 to 3.0, an isocyanate group (NCO) content of 25 to 35, and a viscosity of 150 to 900 centipoise (CPS) is used. do.

For this reason, the polymeric 4,4-diphenylmethane diisocyanate component enhances adhesion to the adherend, but the percent isocyanate group (NCO) content of the polymeric 4,4-diphenylmethane diisocyanate component is 25%. If it is less than, the improvement of adhesive force cannot be expected, the dimensional stability is inferior, and if it exceeds 35%, the adhesive force, compression, and tensile strength will fall rather, and fluidity will fall.

In addition, when the number of functional groups and the numerical value of the viscosity are out of the above range, there is a problem that the reactivity is lowered.

In addition, the reaction ratio of the isocyanate component and the mixed polyol component is preferably NCO / OH, which is a weight ratio of the isocyanate group (-NCO) of the isocyanate component and the hydroxyl group (-OH) of the mixed polyol, 2.5 to 5.0, more preferably 3.5 To 4.5 is suitable. When the NCO / OH ratio is less than 2.5, there is a problem that the reaction between the mixed polyol and the isocyanate does not occur (polyisocyanurate reaction), resulting in insufficient crosslinking density and thus lowering heat resistance, and when the ratio of NCO / 0H exceeds 5.0, There exists a problem that the adhesive force of a rigid polyurethane foam falls, rigidity becomes high too much, and a crushing phenomenon of foam arises.

When the NCO / OH ratio is 2.5 to 5.0, the isocyanate is present in excess. In this case, the isocyanate remaining after the formation of the polyurethane foam is completed forms allophanate and biuret through addition reaction. As a result, the physical properties are improved. The isocyanate at high temperature forms strong isocyanurate bond through its own reaction, which is stronger than general urethane bond, so it is not easily broken. It is improved in chemical stability and thermal stability, and it is excellent in heat and flame resistance. It is possible to maintain low thermal conductivity. Therefore, when the blending ratio of the mixed polyol component and the isocyanate component to be reacted is outside the above range, the object of the present invention cannot be achieved.

Next, the catalyst will be examined in the polyurethane foam composition for pipe insulation having heat resistance of the present invention.

Catalysts used in the present invention are typical catalysts that can be used to obtain polyurethane foams, for example triethylenediamine, tetramethylethylenediamine, 1-methyl-4-dimethylaminoethyl-piperazine, 3-methoxy- N-dimethyl-propylamine, diethylethanol-amine, N-cocomorpholine, N, N-dimethyl-N ', N' dimethylisopropyl-propylene diamine, N, N-diethyl-3-diethyl aminopropyl Amine, triethylamine, tripropylamine, triisopropanolamine, tributylamine, trioctylamine, hexadecyldimethylamine, tris (3-dimethylamino) propylhexahydrotriamine, N-methylmorpholine, N-ethylmol Porin, N-octadecyl morpholine, monoethanolamine, diethanolamine, dimethylethanolamine, triethanolamine, N-methyldiethanolamine, N, N-dimethylethanolamine, diethylenetriamine, N, N, N ' , N'-tetramethylbutanediamine, N, N, N ', N'-tetramethyl-1,3-butanedi Min, N, N, N ', N'-tetraethylhexamethylenediamine, bis [2- (N, N-dimethylamino) ethyl] ether, N, N'-dimethylbenzylamine, N, N-dimethylcyclohexyl Amines, N, N, N ', N', n'-pentamethyldiethylenetriamine, triethylenediamine, formic acid and other salts of triethylenediamine, amino and oxyalkylene adducts of the first and second amines, Amine catalysts such as azacyclic compounds such as N, N-dialkyl piperazines, and β-aminocarbonyl catalysts of various N, N ', N'-trialkylaminoalkylhexahydrotriazines.

It is preferable to use these catalysts individually or in mixture, and the usage-amount is 0.5-3.0 weight part with respect to 100 weight part of said mixed polyol components, More preferably, 1.0-2.0 weight part is suitable. Here, when the amount of the catalyst is less than 0.5 parts by weight, the rigid polyurethane foam production reaction is not completed in the reaction for the present invention, the physical properties can be reduced, so the role of the catalyst can not be expected, if exceeding 3.0 parts by weight excessively This is active and difficult to control, the reaction is terminated without filling the space in the foaming object, there is a problem that can occur carbonization (Scorch) or sponge phenomenon.

Next, the foaming agent will be examined in the polyurethane foam composition for pipe insulation having heat resistance of the present invention.

According to the present invention, the blowing agent uses at least one of hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC) or hydrocarbon (HC) as water (H ₂ O) or fluorocarbon-based blowing agent. When water (H ₂ O) is used alone, 0.5 to 5 parts by weight based on 100 parts by weight of the mixed polyol component, water (H ₂ O), hydrochlorofluorocarbons (HCFC), hydrofluorocarbons (HFC) Alternatively, when using at least one of hydrocarbon (HC), 0.5 to 2.5 parts by weight of water (H ₂ O) and at least one of hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC) or hydrocarbon (HC) It is preferable to use 10-30 weight part. In this case, when water (H ₂ O) is used alone, when water (H ₂ O) is used in an amount less than 0.5 parts by weight, the desired density does not come out. When it exceeds 5 parts by weight, the insulation of the polyurethane foam is inferior and the foam is broken. The adhesive force with the face material is also weakened.

Next, the surfactant will be examined in the polyurethane foam composition for pipe insulation having heat resistance of the present invention.

According to the present invention, the surfactant uses a polysiloxane ether as an organosilicon compound. The amount of the surfactant used at this time is preferably 1 to 4 parts by weight, more preferably 1.5 to 3 parts by weight based on 100 parts by weight of the mixed polyol component. When the amount of the surfactant is less than 1 part by weight, the diffusion of gas by foaming cannot be prevented. When the amount of the surfactant is more than 4 parts by weight, the surface tension of the reactants is lowered to prevent the collapse of the closed cell structure. The effect of the surfactant is almost eliminated. In addition, the viscosity of the surfactant is 100 to 2000 centipoise (cps), the molecular weight is preferably 3,000 to 7,000 g / mol. Viscosity and molecular weight in the above range is suitable for maximizing the suitability and reactivity between materials in the reaction of the surfactant with other raw materials.

In addition, in the polyurethane foam composition of the present invention, a crosslinking agent may be used to reinforce the strength of the polyurethane foam and to shorten the curing time. Ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, glycerol, and butanediol can also be used individually or in mixture of 2 or more types. Particularly, the preferred crosslinking agent is polyethylene glycol or butanediol, and the amount thereof is preferably 2 to 15 parts by weight, more preferably 3 to 5 parts by weight based on 100 parts by weight of the mixed polyol component.

In addition, a flame retardant may be added to further enhance the flame retardancy of the polyurethane foam of the present invention. Flame retardants used in the present invention include tris (2-chloroethyl) phosphate, tris (chloropropyl) phosphate, tris (dipropopropyl) phosphate and the like. When using a flame retardant, the usage-amount is 5-20 weight part with respect to 100 weight part of mixed polyol components, More preferably, it is 10-15 weight part. Moreover, metal compounds, such as antimony trioxide and aluminum hydroxide, can also be used.

Other fillers commonly used in urethane chemistry, stabilizers such as antioxidants, ultraviolet absorbers and the like can be added as necessary.

Hereinafter, examples and comparative examples of the polyurethane foam composition for thermal insulation having heat resistance will be described. Here, PO means propylene oxide, EO means ethylene oxide, SO means styrene oxide, BO means butylene oxide, AO means alkylene oxide.

This test conforms to EN 253, which is a standard made in Europe as a standard for predicting the service life of pipes insulated with rigid polyurethane foam as a heat insulating material at specific working temperatures. This method provides a prediction method for the service life of polyurethane insulation for double insulation pipes and the minimum requirements for insulation. The service life at a certain working temperature is an accelerated aging test, that is, the heat medium oil is heated for a certain time, and then flows into the pipe, and after a certain time, the physical strength and thermal conductivity of the foam are measured and predicted to determine the result. Calculated continuous operating temperature (CCOT) is the temperature of the rigid polyurethane foam which is pipe insulation after flowing the heat medium inside the pipe for 3,600 hours at 160 ℃ or 1,450 hours at 170 ℃ for 120 ℃. Predicted by axial shear tests.

Obtained from the Arrhenius life-stress model used in the shear test, which is mainly applied when the stress is heat (eg temperature).

 <Aging test>

For more than 10 years of use at temperatures between 160 and 200 ° C, testing in the current operating temperature range is not possible because of the time required. Accordingly, assuming that the life of the double insulation tube moves according to the following Arrhenius equation, all supply temperatures (x-axis) can be expected to obtain the expected life (y-axis) on a straight line. Accordingly, in order to predict the service life that can be used in modern times, the current double insulation tube is forcibly aged at an appropriate temperature (220 ~ 270 ℃), and the shear strength value is calculated to find the time when the shear strength value falls below 0.12 MPa. The usable life comes from supplying the aging temperature, ie from 220 ° C to 270 ° C.

                 Q

Ln (L) = ln (A) + ------

                R * T

A: Unknown specific temperature constant Q: Activation energy (kJ / mol.k)

R: Boltzmann constant (J / mol.K) T: Supply temperature

L: Life expectancy at supply temperature

Comparative Example 1

100% by weight of mixed polyol component having a hydroxy group (-OH) value of 430 (35% by weight of polyether polyol with PO or EO added to sorbitol, 15% by weight of polyether polyol with PO or EO added to pentaerythritol, toluenediamine 25 weight% of polyether polyol which added EO or PO to it, the mixed polyol component which consists of 25 weight% of polyether polyol which added EO or PO to ethylenediamine), and dichloromonofluorine with respect to 100 weight part of mixed polyols as a blowing agent. 25 parts by weight of ethane and 0.8 parts by weight of water were added to prepare a resin stock solution, which was prepared using 125 parts by weight of polymeric MDI having an isocyanate group (NCO) content of 30%.

Comparative Example 2

All other conditions were the same as in Comparative Example 1, and 6 parts by weight of the blowing agent was used based on 100 parts by weight of mixed polyol alone. In addition, polymeric MDI having an isocyanate group (NCO) content of 32 was used.

Comparative Example 3

100% by weight of mixed polyol component having a hydroxyl group (-OH) value of 650 (10% by weight of sucrose polyether polyol, 45% by weight of pentaerythritol + OH, 25% by weight of toluenediamine + PO / EO, ethylenediamine + PO 3 parts by weight of water and 15 parts by weight of hydrochlorofluorocarbon (HCFC-141b) were used as a foaming agent.

In addition, a polymeric MDI having an isocyanate group (NCO) content of 25 was used.

Comparative Example 4

The other conditions were the same as in Comparative Example 3, and 0.4 parts by weight of water and 5 parts by weight of hydrochlorofluorocarbon (HCFC-141b) were used for 100 parts by weight of the mixed polyol. In addition, a polymeric MDI having an isocyanate group (NCO) content of 29 was used.

Example 1

Polyester ether obtained by adding PO and EO to 50 weight part of polyester polyols which polycondensed glycols to the dimethyl phthalate polyester polyol, and phthalate base polyester with respect to 100 weight part of 4, 4- diphenylmethane diisocyanate. 15 parts by weight of polyol, 10 parts by weight of polyether polyol obtained by adding AO to caprolactone, 15 parts by weight of polyether polyol obtained by adding SO and BO to glycol, polyether polyol 10 obtained by adding SO and BO to bisphenol To 100 parts by weight of a mixed polyol having a hydroxyl group (-OH) value of 450 parts by weight, 0.8 parts by weight of water and 25 parts by weight of dichloromonofluoroethane (HCFC-141b) were added to form a resin stock solution, and an isocyanate group was added thereto. Polymeric 4,4-diphenylmethane diisocyanate having a (NCO) content of 30% based on 100 parts by weight of mixed polyol 18 0 parts by weight of the mixture was reacted and foamed to prepare a polyurethane foam.

Example 2

Polyester obtained by adding PO and EO to 60 weight part of polyether polyols which polycondensed glycols to the dimethyl phthalate polyester polyol, and adipic acid base polyester with respect to 100 weight part of 4, 4- diphenylmethane diisocyanate 15 parts by weight of ether polyol, 5 parts by weight of polyether polyol obtained by adding AO to caprolactone, 10 parts by weight of polyether polyol obtained by adding SO and BO to glycol, and polyether obtained by adding SO and BO to bisphenol A To 100 parts by weight of a mixed polyol having a hydroxyl group (-OH) value of 350 mixed with 10 parts by weight of polyol, 0.9 parts by weight of water and 28 parts by weight of hydrofluorocarbon (HFC-365mfc) were added to form a resin stock solution, and an isocyanate compound was added thereto. 4,4-diphenylmethane diisocyanate having a group (NCO) content% of 27 is mixed with 190 parts by weight based on 100 parts by weight of the mixed polyol. To prepare a polyurethane foam by foaming.

Example 3

Polyester obtained by adding PO and EO to 70 weight part of polyester polyols which polycondensed glycols to the polyethylene terephthalate polyester polyol, and phthalate base polyester with respect to 100 weight part of 4, 4- diphenylmethane diisocyanate 10 parts by weight of ether polyol, 5 parts by weight of polyether polyol obtained by adding AO to caprolactone, 10 parts by weight of polyether polyol obtained by adding SO and BO to glycol, and polyether polyol obtained by adding SO and BO to bisphenol A 0.8 parts by weight of water and 30 parts by weight of hydrofluorocarbon (HFC-245fa) were added to 100 parts by weight of a mixed polyol having a hydroxyl group (-OH) value of 550 mixed with 5 parts by weight to prepare a resin stock solution. 185 parts by weight of 4,4-diphenylmethane diisocyanate having a content of 32% based on 100 parts by weight of the mixed polyol, By reacting and foaming, a polyurethane foam was prepared.

Example 4

Polyester obtained by adding PO and EO to 50 weight part of polyester polyols which polycondensed glycols to the polyethylene terephthalate polyester polyol, and phthalate base polyester with respect to 100 weight part of 4, 4- diphenylmethane diisocyanate 20 parts by weight of ether polyol, 15 parts by weight of polyether polyol obtained by adding AO to caprolactone, 10 parts by weight of polyether polyol obtained by adding SO and BO to glycol, polyether polyol obtained by adding SO and BO to bisphenol To 100 parts by weight of a mixed polyol having a hydroxy group (-OH) value of 500 mixed with 5 parts by weight, 0.8 parts by weight of water and 30 parts by weight of hydrocarbon were added to form a resin stock solution, and an isocyanate group (NCO) was added thereto. 180 parts by weight of 4,4-diphenylmethane diisocyanate having a content% of 30 is mixed with respect to 100 parts by weight of the mixed polyol, The reaction was carried out to foam to prepare a polyurethane foam.

Example 5

40 parts by weight of a polyester polyol obtained by condensation polymerization of glycols to a dimethyl phthalate polyester polyol and 100 parts by weight of 4,4-diphenylmethane diisocyanate, and a polyester polyol obtained by condensation of glycols to a polyethylene terephthalate polyester polyol. 30 parts by weight, 10 parts by weight of polyester ether polyol obtained by adding PO and EO to phthalate-based polyester, 5 parts by weight of polyether polyol obtained by adding AO to caprolactone, and SO and BO to glycol 10 parts by weight of polyether polyol and 0.9 parts by weight of water were added to 100 parts by weight of a mixed polyol having a hydroxyl group (-OH) value of 500 obtained by adding 5 parts by weight of polyether polyol obtained by adding SO and BO to bisphenol A. A stock solution was prepared, wherein 4,4-diphenylmethane having an isocyanate group (NCO) content of 31% Mixing an isocyanate portion of 195 parts by weight based on 100 parts by weight of the polyol mixture, the reaction was foamed to prepare a polyurethane foam.

The performance of the polyurethane foam produced through the comparative examples and examples are summarized in [Table 1], [Table 2]. Table 1 measures the physical properties before accelerated aging, and Table 2 measures the physical properties after accelerated aging.

In Table 1 and Table 2, the "property" indicated in each section for performance comparison was measured as described below.

First, the free foam density is the foam density (kg / ㎥) of the foam injected and injected into an open box made of plywood having an internal dimension of 200 × 200 × 190 mm, and the product density is the foam density of the actual produced product (kg / ㎥). , Thermal conductivity is the result of measurement (according to KS L 9016) using a laser conductivity measuring instrument (Model No. MA01906).

Core density is a result of measuring the foaming density (kg / ㎥) of the actually produced product in the same manner as the free foaming density.

In addition, the compressive strength was measured using a universal testing machine of hardness precision (according to ASTM D-1621), the shear strength was measured using a universal testing machine of hardness precision (according to ASTM D-1623), and the flexural strength was hardness precision It was measured using a universal testing machine (according to KS M 3809).

Adhesion was measured using a bonding tester from Shinjin Corp. (according to DS 2178), independent foaming rate was based on ASTM D-2856, absorbency was based on EN-253, flame retardancy: KS M 3809 Was measured.

Finally, the accelerated aging test (CCOT) foamed a heat insulating layer of 89.5 mm in 500 kW pipe, and the outer skin was measured using a self-made machine according to EN-253 standard in HDPE 710 mm (thickness: 11.5 mm) pipe. Here, in Comparative Examples 1, 2, 3, and 4, the foam was completely carbonized after 1 week of accelerated aging at 200 ° C., but the test could not be further performed. Even after accelerated aging, the foam did not carbonize and maintained the thermal insulation performance.

TABLE 1

Powder Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example One Example 2 Example 3 Example 4 Example 5 Saint free density (kg / ㎥) 45 42 43 46 46 48 41 45 43 Core Density (kg / ㎥) 87 81 83 86 85 89 81 86 83 Thermal Conductivity (W / mK) 0.0259 0.0265 0.0277 0.0285 0.0231 0.0243 0.0233 0.0249 0.0245 Compressive strength (MPa) 0.475 0.455 0.485 0.488 0.443 0.534 0.435 0.487 0.478 Flexural Strength (MPa) 0.823 0.781 0.831 0.839 0.764 0.885 0.654 0.703 0.711 Shear strength (MPa) 0.413 0.402 0.420 0.425 0.418 0.433 0.365 0.430 0.423 Independent Bubble Rate (%) 94.1 91.5 93.2 94.2 93.5 92.8 94.9 89.0 90.6 Absorption rate (%) 5.92 5.81 5.26 5.33 5.21 4.04 5.73 5.16 5.44 Adhesive force (MPa) 0.264 0.255 0.266 0.270 0.263 0.275 0.260 0.263 0.261 Flame retardant (Combustion distance: mm Burning time: sec) 56 91 51 89 54 85 52 92 51 89 50 85 52 94 53 91 52 93

TABLE 2

Powder Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example One Example 2 Example 3 Example 4 Example 5 Sex Core Density (kg / ㎥)   Not measurable with full carbonization   Not measurable with full carbonization   Not measurable with full carbonization   Not measurable with full carbonization 85 88 81 83 85 Thermal Conductivity (W / mK) 0.0240 0.0268 0.0248 00272 00268 Compressive strength (MPa) 0.225 0.314 0.208 0.205 0.245 Flexural Strength (MPa) 0.395 0.424 0.357 0.332 0.343 Shear strength (MPa) 0.199 0.224 0.194 0.119 0.142 Absorption rate (%) 6.69 6.48 7.85 8.09 7.95 Adhesive force (MPa) 0.135 0.146 0.132 0.131 0.129 Flame retardant (Combustion distance: mm Burning time: sec) 53 95 51 89 53 97 55 100 54 99

As described above, the polyurethane foam obtained by the present invention has a core density of 60 kg / m 3 or more before thermal aging, a thermal conductivity of 0.0256 W / mK or less, an independent bubble ratio of 88% or more, a compressive strength and a flexural strength of 0.3 MPa or more, and a shear steel Figure preferably has a characteristic of 0.2MPa or more at room temperature. In addition, the inner adhesive force for confirming the adhesive strength with the adherend is an indicator for determining the life of the insulating material, so it must have a value of 0.2MPa or more. In addition, the flame retardancy of the polyurethane foam of the present invention has a self-extinguishing ability according to the provisions of KS M 3809

In addition, after accelerated aging, the core density is 60 kg / m 3 or more, the thermal conductivity is 0.0326 W / mK or less, the compressive strength and the flexural strength are 0.15 MPa or more, and the shear strength is preferably 0.10 MPa or more at room temperature. In addition, the inner adhesive force for confirming the adhesive strength with the adherend is an indicator for determining the life of the insulating material, so it must have a value of 0.10 MPa or more. In addition, the flame retardancy of the polyurethane foam of the present invention has a self-extinguishing property according to the provisions of KS M 3809.

Looking at the experimental results of Table 1, Comparative Examples 1 to 4 is a result of foaming a polyurethane foam composition having a composition and content of polyol different from the present invention. Comparative Examples 1 to 4 had a satisfactory result in the product density of 81 ~ 87kg / ㎥, it can be seen that the thermal conductivity exceeds 0.0256W / mK, there is a problem in the thermal insulation performance.

On the other hand, in the case of Examples 1 to 5, it can be seen that the measurement of the thermal conductivity and physical strength generally have excellent properties. For example, the thermal conductivity not only satisfies the requirements of 0.0233 MPa and 0.0243 MPa, respectively, but also shows that the compressive and flexural strength, the shear strength, and the inner surface (pipe) adhesion also exhibit excellent performances satisfying the specifications.

In addition, looking at the experimental results of Table 2, Comparative Examples 1 to 4 by foaming a polyurethane foam composition having a composition and content of a polyol different from the present invention in a pipe, a high temperature heat medium oil or steam of 220 to 270 ℃ The result is when it is spilled into a pipe. Comparative Examples 1 to 4 were completely carbonized when subjected to accelerated aging for 1 week at a temperature of 220 ° C., and thus the physical properties could not be measured. That is, it could not withstand the high temperature exceeding 120 degreeC.

On the other hand, in the case of Examples 1 to 5, even though accelerated aging at 270 ℃ for more than 1000 hours, the carbonization phenomena was small, and the thermal conductivity and physical strength of the measurement resulted in excellent properties in spite of long exposure at high temperature. Able to know. For example, the thermal conductivity not only satisfies the requirements of 0.0240 MPa and 0.0268 MPa, respectively, but also shows that the compressive and flexural strength, the shear strength, and the inner surface (pipe) adhesion also exhibit excellent performance.

That is, from the above experimental results, it is understood that the foam using the polyurethane foam composition for pipe insulation having heat resistance according to the present invention is a revolutionary invention that can serve as a heat insulating material even at a high temperature far exceeding the available temperature of the conventional polyurethane. Can be.

Hereinafter, an embodiment of a foaming method using a polyurethane foam composition for heat insulation having heat resistance according to the present invention will be described with reference to FIG. 4.

Method for producing a polyurethane foam composition for pipe insulation having heat resistance basically comprises a reaction solution production step (S10), isocyanate production step (S20), semi-continuous reaction step (S30).

First, the reaction solution preparation step (S10) is a reaction of propylene oxide and ethylene oxide to a polyester containing at least one of 50 to 100 parts by weight of polyester polyol, phthalate or adipic acid, based on 100 parts by weight of isocyanate 10 to 40 parts by weight of phthalate polyester ether polyol obtained by reacting alkylene oxide with caprolactone, and 5 to 20 parts by weight of caprolactone polyether polyol obtained by reacting styrene oxide and butylene oxide with glycol Preparing a reaction solution by mixing 10 to 30 parts by weight of a polyol, 5 to 15 parts by weight of a bisphenol A polyether polyol obtained by reacting a styrene oxide and a butylene oxide, and a catalyst, a foaming agent, and a surfactant. to be.

Here, the components of the mixed polyol and the content thereof are as described above.

Isocyanate manufacturing step (S20) is a step of preparing an isocyanate including the polymeric 4,4-diphenylmethane diisocyanate. It may also be prepared by adding modified diphenylmethane diisocyanate to the polymeric 4,4-diphenylmethane diisocyanate. The components of isocyanate and their contents are also as described above.

In addition, the reaction ratio of the isocyanate component and the mixed polyol component is also as described above.

Semi-continuous reaction step (S30) is a step of reacting the reaction solution and the isocyanate. The reaction step is any one of low pressure (S31) to react by mechanically mixing at a pressure of 1 to 10 bar or high pressure (S32) to react by colliding the reaction solution and the mixed isocyanate at a pressure of 50 to 200 bar. The reaction proceeds.

In addition, the semi-continuous reaction step (S30) is characterized by adjusting the position to be foamed by moving the foaming machine mixing head 60 in the foaming progress direction. Here, the foaming progress direction, since the reaction proceeds by filling the foam from the inside of the pipe, that is, the closed lid 20, the foaming machine mixing head 60 is moved from the inside of the pipe to the outside, that is, It means the moving direction of the foaming machine.

As shown in FIG. 1, the conventional spray foaming method requires a fast reaction time, which is a problem of sagging or spun off the foam or a serious variation in the insulation thickness if the reaction time is not appropriate. In addition to the high risk of this problem, the surface must be maintained evenly, and unlike the injection type, there can be a problem due to the lack of adhesion between the foam and the exterior.In addition to the facility for rotating the pipe, a separate facility for extruding the polyethylene jacket is required. There has been a problem of poor quality and price competitiveness.

In addition, as shown in Figure 2, the injection foaming method commonly used in the prior art by inserting the foam into the foam composition through the injection hole from the outside after inserting a general inner tube in each foam completed by the separate assembly separately. The foam is formed by injecting the foamed composition through the foam composition inlet from the outside of the assembled double thermal insulation tube. The length of the foam is made from 0.3m up to 16m, and the long product of 6 ~ 12m length is mainly used. As it is applied to make, the foam composition requires slow reactivity to completely fill the interior. However, this slow reactivity requires not only a long curing time but also polyisocyanurate reactions suitable for heat resistance require very fast reactivity and are not suitable for the formation of foams requiring heat resistance.

Therefore, the conventional spray foaming method and the injection foaming method are inadequate for the polyisocyanurate reaction of the polyurethane foam composition for pipe insulation of the present invention that requires rapid reactivity and is suitable for heat resistance, as shown in FIG. After placing the 60 between the inner tube and the outer tube, the foamer head 60 is ejected between the inner tube 10 and the outer tube 30 according to the foaming speed of the polyurethane foam 40, and at the same time, the foam composition is ejected and foamed. The semi-continuous foaming method of the present invention has been developed.

This is because the head of the polyurethane foamer is placed inside the pre-assembled double heat insulating tube, and then the composition is discharged and foamed. The foam head is moved to the inlet while maintaining a constant distance according to the foaming speed. It can be said that it is an optimal method suitable for the polyisocyanurate reaction.

In addition, there is no need for a separate assembly process, which minimizes the number of people.In addition, it checks the foaming status of individual products to minimize the defective rate and minimize the work space similar to continuous type. There is no need to insert spacers to maintain the spacing, which can reduce heat loss due to thermal bridges caused by the spacers, thereby improving thermal insulation performance and durability of the foam. In addition, it is possible to apply not only the continuous type working horizontally but also the injection type giving the inclination of 3 ~ 15 degrees. Various working conditions can be given according to the reactivity and the desired physical properties.

In other words, the advantages of the continuous type and the injection type of the existing combination is used, and this has the advantage of improving the performance of the product, such as heat insulation and durability, as well as improving the economics such as productivity improvement and defect rate reduction.

It has been described in detail above with reference to preferred embodiments of the present invention. However, the scope of the present invention is not limited to the above embodiments, but may be embodied in various forms of embodiments within the appended claims. Without departing from the gist of the invention as claimed in the claims, any person skilled in the art to which the invention pertains is considered to be within the scope of the claims of the invention to the various possible modifications possible.

1 is a cross-sectional view showing the foaming equipment used in the conventional spray foaming method

Figure 2 is a cross-sectional view showing the foaming equipment used in the conventional injection foaming method

Figure 3 is a cross-sectional view showing the foaming equipment used in the semi-continuous foaming method of the present invention

Figure 4 is a flow chart sequentially showing an embodiment of a foaming method using a polyurethane foam composition for heat insulation having a heat resistance according to the present invention.

<Description of the symbols for the main parts of the drawings>

10: inner tube (feed pipe) 50: spacer

20: airtight lid 60: mixing head

30: appearance (jacket pipe) 70: foaming machine

40: polyurethane foam 80: support table

100: inner tube (feed pipe) 600: water tank

200: polyethylene foil 700: cutting saw

300: double conveyor 800: polyurethane foaming machine

400: polyurethane foam 900: mixing head

500: polyethylene extruder

1000: foaming machine 5000: spacer

2000: Mixing head 6000: appearance (jacket pipe)

3000: airtight lid 7000: inner tube (feed pipe)

4000: polyurethane foam 8000: support table

Claims (16)

In the polyurethane foam composition for pipe insulation having heat resistance containing a mixed polyol, isocyanate, catalyst, blowing agent, surfactant, The mixed polyol is based on 100 parts by weight of the isocyanate, (1) 50 to 100 parts by weight of polyester polyol; (2) 10 to 40 parts by weight of a phthalate polyester ether polyol obtained by reacting a propylene oxide and ethylene oxide with a polyester containing at least one of phthalate or adipic acid; (3) 5 to 20 parts by weight of caprolactone polyether polyol obtained by reacting caprolactone with an alkylene oxide; (4) 10 to 30 parts by weight of a glypol polyether polyol obtained by reacting glycol with styrene oxide and butylene oxide; 5 to 5 parts by weight of bisphenol A polyether polyol obtained by reacting bisphenol A with styrene oxide and butylene oxide; The isocyanate is polyurethane foam composition for heat insulation having a heat resistance, characterized in that it comprises a polymeric 4,4-diphenylmethane diisocyanate. delete The method of claim 1, The polyester polyol is a dimethyl phthalate polyester polyol or polyurethane foam composition for heat insulation with a heat resistance, characterized in that one of the polyester polyol polycondensation of glycol to at least one of phthalic anhydride or polyethylene terephthalate. The method according to claim 1 or 3, The isocyanate has a functional group of 2.5 to 3.0, isocyanate group (NCO) content of 25 to 32, characterized in that it comprises a polymeric 4,4-diphenylmethane diisocyanate having a viscosity of 150 to 900 centipoise (CPS) Polyurethane foam composition for pipe insulation which has heat resistance. The method according to claim 1 or 3, Polyurethane foam composition for heat insulation with heat resistance, characterized in that the weight ratio of the isocyanate group (NCO) of the isocyanate to the hydroxyl group (-OH) of the mixed polyol is 2.5 to 5.0. The method according to claim 1 or 3, The mixed polyol is a polyurethane foam composition for pipe insulation having heat resistance, characterized in that the hydroxyl group (-OH) value is 200 to 600. The method according to claim 1 or 3, The catalyst is an amine-based catalyst, the polyurethane foam composition for heat insulation having a heat resistance, characterized in that it comprises 0.5 to 3.0 parts by weight based on 100 parts by weight of the mixed polyol. The method according to claim 1 or 3, The blowing agent is 0.5 to 5 parts by weight of at least one of water (H ₂ O), hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC) or hydrocarbon (HC) based on 100 parts by weight of the mixed polyol or the mixture 0.5 to 2.5 parts by weight of water (H ₂ O) and 10 to 30 parts by weight of at least one of hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC) or hydrocarbon (HC) based on 100 parts by weight of polyol Polyurethane foam composition for pipe insulation having heat resistance. The method according to claim 1 or 3, The surfactant is a polysiloxane ether having a molecular weight of 3000 to 7000 g / mol and a viscosity of 100 to 2000 centipoise (CPS), and is 1 to 4 parts by weight based on 100 parts by weight of the mixed polyol. Urethane foam composition. In the foaming method using a polyurethane foam composition for heat insulating pipe having a heat resistance containing a mixed polyol, isocyanate, catalyst, blowing agent, surfactant, Per 100 parts by weight of the isocyanate, 50 to 100 parts by weight of polyester polyol, 10 to 40 parts by weight of phthalate polyester ether polyol obtained by reacting propylene oxide and ethylene oxide with a polyester comprising at least one of phthalate or adipic acid, alkyl to caprolactone 5 to 20 parts by weight of a caprolactone polyether polyol obtained by reacting a styrene oxide, 10 to 30 parts by weight of a glypol polyether polyol obtained by reacting a styrene oxide and a butylene oxide with glycol, a styrene oxide and a butylene oxide A reaction solution preparing step of preparing a reaction solution by mixing a mixed polyol obtained by reacting 5 to 15 parts by weight of a bisphenol a polyether polyol with a catalyst, a blowing agent, and a surfactant; An isocyanate preparation step of preparing an isocyanate including the polymeric 4,4-diphenylmethane diisocyanate; A semi-continuous reaction step of reacting and reacting the reaction solution and the isocyanate at a position to be foamed by using a foaming machine, and foaming. The method of claim 10, The semi-continuous reaction step, the foaming method using the polyurethane foam composition for heat insulation having a heat resistance, characterized in that for controlling the position to be foamed by moving the foaming machine mixing head in the foaming progress direction. The method according to claim 10 or 11, wherein The semi-continuous reaction step is made of any one of low pressure to react by mechanically mixing at a pressure of 1 to 10 bar or high pressure to react by collision of the reaction solution and the isocyanate at a pressure of 50 to 200 bar. Foaming method using a polyurethane foam composition for pipe insulation having a heat resistance. The method according to claim 10 or 11, wherein The isocyanate has a functional group of 2.5 to 3.0, isocyanate group (NCO) content of 25 to 32, characterized in that it comprises a polymeric 4,4-diphenylmethane diisocyanate having a viscosity of 150 to 900 centipoise (CPS) Foaming method using the polyurethane foam composition for pipe insulation having a heat resistance. The method according to claim 10 or 11, wherein The weight ratio of the isocyanate group (NCO) of the isocyanate to the hydroxyl group (-OH) of the mixed polyol is 2.5 to 5.0, the mixed polyol is a pipe having heat resistance, characterized in that the hydroxyl group (-OH) value of 200 to 600 Foaming method using a polyurethane foam composition for thermal insulation. The method according to claim 10 or 11, wherein The blowing agent is 0.5 to 5 parts by weight of at least one of water (H ₂ O), hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC) or hydrocarbon (HC) based on 100 parts by weight of the mixed polyol or the mixture 0.5 to 2.5 parts by weight of water (H ₂ O) and 10 to 30 parts by weight of at least one of hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC) or hydrocarbon (HC) based on 100 parts by weight of polyol Foaming method using a polyurethane foam composition for pipe insulation having heat resistance. 12. Polyurethane foam for heat insulation having a heat resistance, characterized in that produced by the claim 10.

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