KR20040075493A - Polyisocyanurate foam for ultra-low-temperature insulation, and insulating material by using it - Google Patents

Abstract

PURPOSE: Provided is a glass fiber-reinforced polyurethane foam for keeping ultralow temperature, which has excellent mechanical strength without using a fluorocarbon-based foaming agent such as CFC-11 and HCFC-141b. CONSTITUTION: The polyurethane foam is prepared by reacting a polyol component with an isocyanate component in the presence of a foaming agent, a reaction catalyst and other additives. The polyol component is a mixed polyol composition comprising: (a) 15-35 wt% of the polyol obtained by addition of propylene oxide and ethylene oxide to sorbitol; (b) 30-50 wt% of the polyol obtained by addition of propylene oxide and ethylene oxide to sucrose; and (c) 25-50 wt% of the polyol obtained by addition of diethylene glycol or propylene glycol to phthalic anhydride. The isocyanate component is polymeric MDI having a functionality of 2.6-3.0. The mixed polyol composition is used in the amount of 80-90 parts by weight based on 100 parts by weight of the polymeric MDI. The foaming agent is water used alone in the amount of 0.5-2.0 parts by weight based on 100 parts by weight of the polyol component. The polyurethane foam further comprises 5-25 parts by weight of fiber reinforcing material based on 100 parts by weight of the polyol component.

Description

Glass fiber reinforced polyurethane foam for cryogenic cold storage and insulation using same {POLYISOCYANURATE FOAM FOR ULTRA-LOW-TEMPERATURE INSULATION, AND INSULATING MATERIAL BY USING IT}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to rigid polyurethane foams that exhibit excellent properties as heat insulators, and more particularly to polyurethane foams and heat insulators that exhibit excellent thermal insulation and mechanical properties even at very low temperatures without the use of fluorocarbon blowing agents.

Polyurethane foams are usually obtained by reacting a polyol component with an isocyanate component in the presence of a blowing agent, reaction catalyst and other additives.

In general, polyurethane foam is most commonly used in refrigerators, freezing containers, low-temperature warehouses, etc., which require high thermal insulation as an insulating material having the highest thermal insulation property among oil and inorganic insulating materials. This is because polyurethane foam is composed of independent bubbles, excellent heat insulation, and can control low density foam by controlling the amount and type of blowing agent.

Such a conventional polyurethane foam is mainly applied where the use conditions are relatively good, such as -15 ℃ at room temperature. However, since LNG, which has recently been spotlighted as clean energy, must be stored and transported at an ultra-low temperature of -165 ° C. or lower, general polyurethane foam is not suitable for cold storage of LNG carriers. This is because the conventional polyurethane foam shrinks, cracks, twists, etc. in the cryogenic state below -165 ℃ or easily broken by external impact.

Therefore, conventionally, heat insulating materials having good mechanical strength such as styropol, perlite and PVC foam have been used for cryogenic insulation having a temperature of -165 ° C or lower. However, these insulating materials have excellent mechanical strength, but the insulating property is only about 48.6% compared to polyurethane, so there is a problem that the amount of loss due to evaporation during LNG transportation exceeds 0.15%.

Therefore, there has been a demand for the development of a rigid polyurethane foam having excellent mechanical properties such as compressive strength, tensile strength and low temperature dimensional stability while maintaining excellent thermal insulation even at very low temperatures.

In accordance with such a request, Korean Patent Nos. 10-0278363, 10-0278364, and 10-0278365 propose polyurethane foams and insulating materials having excellent thermal insulation and mechanical properties even at very low temperatures.

The above-mentioned conventional polyurethane foam uses a fluorocarbon blowing agent such as CFC-11 (trichloromonofluoromethane) or HCFC-141b (dichloromonofluoroethane) as a blowing agent.

However, these fluorocarbon blowing agents are regulated by the Montreal Protocol because they destroy the ozone layer and cause global warming. In developed countries, CFC-11 was already banned from use and production in 1995, and HCFC-141b is also available under the Montreal Protocol until 2030, but as part of efforts to protect the global environment, the EU and the US In developed countries such as Japan and Japan, the regulations on the use of HCFC-141b are set to 2003 in their own regulations, after which the production, import, export and use of the substances are prohibited.

Therefore, HFCs (hydrofluorocarbons), cyclopentane, water, and the like have recently been in the spotlight as blowing agents to replace CFC-11 and HCFC-141b. However, these alternative blowing agents are basically less thermally conductive than the conventional CFC-11 or HCFC-141b. In addition, when the polyurethane is molded with this foaming agent, the mechanical strength becomes weak, causing severe shrinkage at low temperatures, poor adhesion to the face plate, and brittleness, which makes it difficult to manufacture the product, and significantly reduces flame retardancy. Physical properties are inferior to polyurethane foam using a blowing agent.

An object of the present invention is to provide a cryogenic cold insulation polyurethane foam having excellent mechanical strength without using a fluorocarbon blowing agent such as CFC-11, HCFC-141b and heat insulating material using the same.

Other objects and advantages of the invention will be described below and will be appreciated by the embodiments of the invention. Furthermore, the objects and advantages of the present invention can be realized by means and combinations indicated in the appended claims.

In order to prevent global warming due to the use of fluorocarbon blowing agents such as CFC-11 and HCFC-141b, the present inventors used water, which was usually used as an auxiliary blowing agent, alone to prepare polyurethane foams.

In addition, a fiber reinforcement was added to the polyurethane foam to compensate for the decrease in mechanical strength of the polyurethane foam due to the use of water as a blowing agent.

The polyurethane foam as one aspect according to the present invention is produced by reacting a polyol component with an isocyanate component in the presence of a blowing agent, reaction catalyst and other additives.

In this case, the polyol component is 15 to 35% by weight of a polyol obtained by adding propylene oxide and ethylene oxide to (a) sorbitol, (b) 30 to 50% by weight of polyol obtained by adding propylene oxide and ethylene oxide to sucrose, (c) a mixed polyol composition comprising 25 to 50% by weight of a polyol obtained by adding diethylene glycol or propylene glycol to phthalic anhydride;

The isocyanate component is a polymeric MDI having 2.6 to 3.0 functional groups;

The blowing agent is used alone 0.5 to 2.0 parts by weight of water based on 100 parts by weight of the polyol component;

The polyurethane foam includes 5 to 25 parts by weight of fiber reinforcement based on 100 parts by weight of the polyol component.

80-90 weight part of mixed polyol components are mix | blended with respect to the said isocyanate component and the mixed polyol component.

Moreover, the heat insulating material as another aspect which concerns on this invention is manufactured using the polyurethane foam of the structure mentioned above.

A feature of the present invention is a rigid polyurethane foam having excellent mechanical properties even at very low temperatures by mixing a resin solution containing a mixed polyol composition, a blowing agent, a catalyst, and other additives having a special composition as a polymer component and an isocyanate component having a special composition as an isocyanic acid component. To prepare.

In particular, the present inventors mixed a polyol component having a molecular weight of 300 to 800 with two or more hydroxyl groups, a polyisocyanate component having at least two or more isocyanate groups, a blowing agent, a catalyst, and other additives to form a continuous strand mat such as glass fiber. By reacting on (CSM: Continous Strand Mat), it was possible to prepare a rigid polyurethane foam having high strength and excellent low temperature dimensional stability even at very low temperatures below -165 ° C. while maintaining excellent thermal insulation characteristic of a general rigid polyurethane foam.

Polyurethane foams obtained by the present invention have a density of 117 to 130 kg / m 3, a thermal conductivity of 0.0235 kcal / m · hr · ° C. or less, an independent bubble ratio of 90% or more, and a horizontal compressive strength of 12.0 ° C. at a low temperature of −195 ° C., respectively. It is more than kg / cm 2 and 21.0kg / cm 2, the compressive modulus is at least 470kg / cm 2 and 700kg / cm 2 at room temperature and ultra-low temperature, respectively, the tensile strength is at least 24.0kg / cm 2 and 27.0kg / cm 2 at room temperature and ultra-low temperature, respectively. In addition, the polyurethane foams obtained by the present invention have a tensile modulus of 1100 kg / cm 2 and 1900 kg / cm 2 at room temperature and ultra low temperature, respectively, and a shear strength of 10.0 kg / cm 2 and 12.0 kg / cm 2 at room temperature and ultra low temperature, respectively, and the coefficient of linear expansion is foamed. Horizontal and vertical directions of 25 × 10-6 and 70 × 10-6 or less show excellent mechanical properties in cryogenic conditions.

The mixed polyol component used in the present invention includes (a) 15 to 35% by weight of polyol obtained by adding propylene oxide and ethylene oxide to sorbitol, and (b) polyol 30 to 50 obtained by adding propylene oxide and ethylene oxide to sucrose. It consists of a mixed polyol composition containing 25 to 50 weight% of the polyol obtained by adding diethylene glycol and propylene glycol to weight% and (c) phthalic anhydride.

At this time, the average OH value of the mixed polyol composition is preferably 350 ~ 550. If the average OH value of the mixed polyol composition is 350 or less, the mechanical strength and low temperature dimensional stability of the product is inferior, and if the average OH value exceeds 550, cracking and thermal conductivity increase. That is, the average OH value out of the above-mentioned proper range becomes a cause of the defect of a product, and productivity falls. Therefore, an average OH value of 350 to 550 is preferred for producing a stable rigid polyurethane foam.

On the other hand, as the isocyanate component to be reacted with the mixed polyol composition, polymeric MDI having a functional group of 2.6 to 3.0 was used. The isocyanate component preferably has an average NCO% of 29% to 32%. At this time, fluidity | liquidity falls that NCO% of the said isocyanate component is 29% or less, and low temperature dimension stability falls when it is 32% or more. Therefore, the NCO% of the isocyanate component is preferably 29 to 32 to produce a stable rigid polyurethane foam.

As for the reaction ratio of an isocyanate component and the mixed polyol component, it is preferable that NCO / OH which is ratio of NCO of an isocyanate and OH of a polyol is 1.0-1.3, More preferably, it is 1.10. At this time, when the ratio of NCO / OH is 1.0 or less, the unreacted OH remains, so that the resin strength is very low and shrinks. In addition, when the ratio of NCO / OH exceeds 1.3 is left a lot of unreacted NCO is easy to break the resin.

Therefore, when the blending ratio of the polyol component and the isocyanate component to be reacted with it is outside the above range, the object of the present invention cannot be achieved.

In addition, in a foam using a non-fluorocarbon blowing agent such as water, the flame retardancy is very low, and to overcome this, a flame retardant is used. However, 0 to 20 parts by weight is preferable with respect to 100 parts by weight of the polyol component. Preferably it is 0-15 weight part. Here, 0 parts by weight indicates that no flame retardant is used, and at 20 parts by weight or more, the desired flame retardant effect can no longer be obtained.

The rigid polyurethane foam of the present invention is made of a mixed polyol component and an isocyanate component of a special composition as a base material and reacted in the presence of a blowing agent, a reaction catalyst and other additives, and a fiber reinforcement of a special composition is added thereto to prevent shrinkage and high strength at very low temperatures. It can be maintained.

Blowing agents generally used in rigid polyurethane foams include water, carboxylic acids, fluorocarbon-based blowing agents or inert gases such as carbon dioxide and air.

According to the present invention, water is used alone as the blowing agent, but 0.5 to 2.0 parts by weight is preferable with respect to 100 parts by weight of the polyol component. Here, when water is used alone as the blowing agent, the desired density does not come out when the water usage is 0.5 or less, and when the water is 2.0 or more, the insulation of the polyurethane foam is inferior and the foam is broken.

In addition, the reaction catalyst used in the present invention is a typical catalyst that can be used to obtain a rigid polyurethane foam, for example triethylamine, tripropylamine, triisopropanolamine, tributylamine, trioctylamine, hexadecyldimethyl Amine, N-methylmorpholine, N-ethylmorpholine, N-octadecylmorpholine, monoethanolamine, diethanolamine, dimethylethanolamine, triethanolamine, N-methyldiethanolamine, N, N-dimethylethanolamine , Diethylenetriamine, N, N, N ', N'-tetramethylbutanediamine, N, N, N', N'-tetramethyl-1.3-butanediamine, N, N, N ', N'-tetra Ethylhexamethylenediamine, bis [2- (N, N-dimethylamino) ethyl] ether, N, N-dimethylbenzylamine, N, N-dimethylcyclohexylamine, N, N, N ', N', n- Pentamethyldiethylenetriamine, triethylenediamine, formic acid and other salts of triethylenediamine, amino groups and oxyalkylene adducts of the first and second amines, N, N-di Kill piperazine and Class aza ring compounds, such as the number of N, N ', N' '- Tree is alkylaminoalkyl hexahydro-triazol jinryu of β- aminocarbonyl catalyst such as an amine-based urethane catalyst.

These catalysts are used individually or in mixture, The usage-amount is preferable 0.5-2 weight part with respect to 100 weight part of polyol components, More preferably, it is 0.5-1 weight part.

As the surfactant, a polyalkylene glycol silicone copolymer is used as the organic silicone compound generally used in polyurethane foam production. The amount of the surfactant used is preferably 1.0 to 4.0 parts by weight, more preferably 1.5 to 3.0 parts by weight based on 100 parts by weight of the polyol component.

Moreover, in the polyurethane foam of this invention, a crosslinking agent can also be used for strength reinforcement and shortening of hardening time of a polyurethane foam. As a crosslinking agent, the well-known crosslinking agent generally used for manufacture of a polyurethane foam can be used. Examples thereof include ethylene glycol, propylene glycol, butanediol, and glycerol, and these may be used alone or in combination of two or more thereof. Particularly preferred crosslinking agents are butanediol or glycerol.

If the crosslinking agent is used, the amount thereof is preferably 0 to 15 parts by weight, more preferably 0 to 10 parts by weight based on 100 parts by weight of the polyol component. Herein, the amount of the crosslinking agent being 0 parts by weight based on 100 parts by weight of the polyol component indicates the case where the crosslinking agent is not used.

In addition, the rigid polyurethane foam of the present invention may be added with a flame retardant to enhance the flame retardancy. Examples of the flame retardant used in the present invention include tris (2-chloroethyl) phosphate, tris (chloropropyl) phosphate, tris (dipropopropyl) phosphate, pentabromodiphenyloxide and the like. When using a flame retardant, the usage-amount is 0-20 weight part with respect to 100 weight part of polyol components, More preferably, it is 0-15 weight part. Here, the amount of the flame retardant to 0 parts by weight relative to 100 parts by weight of the polyol component indicates a case where no flame retardant is used.

In addition, a nucleating agent may be used to make the size of the cell fine for the purpose of improving the thermal insulation performance of the rigid polyurethane foam of the present invention. Nucleating agents used in the present invention include perfluorocarbons, titanium oxide, titanium oxide compounds, carbon black and the like. When using a nucleating agent, the usage-amount is 0-10 weight part with respect to 100 weight part of polyol components, More preferably, it is 0-5 weight part. Herein, the amount of the nucleating agent being 0 parts by weight based on 100 parts by weight of the polyol component indicates the case where no nucleating agent is used.

In addition, in the rigid polyurethane foam of the present invention, it is preferable to contain 5 to 25 parts by weight of the fiber reinforcement with respect to 100 parts by weight of the polyol component in order to prevent shrinkage and maintain high strength at an extremely low temperature of -165 ° C or lower. In particular, the cold insulation material of the LNG carrier ship is required to add the fiber reinforcement material to further strengthen the mechanical strength because cracks and shrinkage should not occur even when the ship shakes or vibrates during transportation.

Examples of the fiber reinforcing material usefully used in the present invention include synthetic fibers such as glass fibers, polyamides, polyesters, and inorganic fibers such as carbon fibers and ceramic fibers. Of these, glass fiber may be mentioned as a fiber reinforcing material suitable for the present invention, and it is particularly preferable to use a glass fiber mat laminate.

As for the appropriate content rate of the glass fiber added to this invention, 7-25 weight part is preferable with respect to 100 weight part of polyol components, Especially 9-11 weight part is more preferable. At this time, if the glass fiber content is less than 7 parts by weight, low-temperature shrinkage stability and cracking prevention effect are inferior. If the content exceeds 25 parts by weight, abnormal foaming and foam cracking occur when foaming the polyurethane foam solution. do.

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

When glass fibers are added to the expanded stock solution in which the polyol component and the isocyanate component are mixed, it is very important to uniformly distribute the glass fibers. This is because the physical properties of the polyurethane foam also can not secure uniformity if the glass fibers are not evenly distributed in the foam.

In order to uniformly distribute the glass fibers in the urethane foam, the production method of hard urethane should be changed.

Rigid polyurethane foams are largely divided into slabstock foam and mold foam according to the manufacturing method.

The continuous manufacturing method is generally manufactured in a free-foaming form in which the urethane composition is mixed at a predetermined ratio, and has a uniform internal structure of the foam by receiving a relatively low resistance when forming a foam due to foaming. Therefore, the foam produced in this manner is cut to a certain size, and then a panel such as plywood is attached to both surfaces, or in some cases, the foam itself is used as a heat insulating material.

The intermittent manufacturing method is to be molded by injecting a urethane composition into a mold of a predetermined shape to be used as a heat insulating material of a product having a predetermined structure, such as a refrigerator, a freezing container, a freezing panel. Once the mold foam is injected into the mold, there is no need for post-treatment such as cutting, so the loss is low and the productivity is high. However, this production method is very difficult to uniformly distribute the glass fibers in the urethane foam.

Therefore, a continuous production method capable of achieving a uniform distribution of glass fibers by continuously supplying two or more layers of glass fiber mat laminates to a conveyor with an open top and evenly injecting the foamed stock solution into the laminates is suitable for the present invention. . The glass fiber used here is preferably a continuous strand mat (CSM: Continuous Strand Mat) that can be continuously supplied when the polyurethane foam production method is continuous.

The glass fiber mat laminate used in the present invention is formed by a plurality of glass fiber mats (about 90 m in length) are continuously fed onto a conveyor and laminated at the same time. The glass fiber mat laminate is preferably used by laminating a long fiber mat of 3 to 9 layers, but more preferably 5 to 8 layers.

The glass fiber mat is formed by filaments of 25 microns or less are bonded by a solid powdery polyester adhesive. At this time, the amount of the polyester adhesive is preferably minimized within the range of maintaining the shape of the mat state. In the case of the present invention, it is appropriate that the amount used is 5% by weight or less, preferably 1.5 to 3% by weight, based on the weight of the fiber.

At this time, when the amount of use exceeds 5% by weight, it is difficult to dissociate between the glass fibers of the mat when the polyurethane foam stock solution is foamed, so that even distribution of the glass fibers is not made, and thus a good foam cannot be obtained. In addition, when 1.5% by weight or less is used, it is difficult to maintain the shape as a long fiber mat because the bonding of the filament is not sufficient.

In addition, the polyurethane foam can be produced by one-shot method, prepolymer method, spray method and other various well-known methods depending on the method of reacting the raw materials.

The one-shot method is a method in which all of the raw materials such as the isocyanate component and the polyol component are added and reacted at the same time. This one-shot method is simple and easy to operate, while the reaction occurs at a time, so the reaction rate is relatively difficult to control, and a large amount of heat of reaction is generated, resulting in a crack inside the foam.

In contrast, the prepolymer method is a method in which a part of the polyol component is reacted with an isocyanate component in advance and then another raw material is further reacted thereto. Therefore, this prepolymer method has the advantage that the reaction rate is relatively slow and the reaction rate is high, and the foam viscosity rise rate according to the reaction can be filled in every corner even in a complex structure, while the manufacturing step is lengthened and the price can be increased. exist.

Therefore, in the present invention, the one-shot method is used in consideration of workability, productivity, and cost. However, polyols and additives are appropriately adjusted so that thermal scorch and cracks inside the foam due to the generation of a large amount of heat generated by the reaction may occur.

The foaming machine may use high pressure or low pressure foaming machines conventionally used in the polyurethane industry.

In addition, the foaming conditions are different depending on the type of foaming machine, but the stock solution temperature is usually 18 ~ 20 ℃, discharge amount is preferably about 30 ~ 80kg / min.

If the initial reaction time of the foam is too late, the curing may be late and the productivity may be reduced. If the initial reaction time is too late, the viscosity may increase rapidly during foaming, so that impregnation of the glass fiber may occur.

In the case of the present invention, the foam reaction time is preferably maintained about 30 to 80 seconds.

In addition, when the viscosity of the stock solution is high, impregnation of the stock solution with respect to the fiber reinforcing material such as glass fiber worsens, and thus, the fiber reinforcing material is not uniformly distributed in the polyurethane foam after the foaming is completed. Therefore, if possible, it is necessary to use a raw material having a low viscosity, and particularly preferably about 300 to 1500 cps at 25 ° C.

Hereinafter, a preferred embodiment of the manufacturing method of the rigid polyurethane foam of the present invention will be described. Looking at the process for producing a rigid polyurethane foam of the present invention using a continuous production equipment in detail as follows.

The glass fiber mat laminate in a continuous state is supplied to the raw material supply stage of the upper open conveyor, and the foamed polyurethane stock solution (a mixture of polyol component and isocyanate component) is evenly mixed on the top surface of the glass fiber mat laminate to produce line speed and discharge amount. While discharging the discharge port to the left and right while adjusting the discharge liquid so that the surface of the presentation liquid to match the surface of the glass fiber mat. The glass fiber mat sprayed with the foam stock solution is suspended in the foam stock solution according to the free expansion of the foam stock solution, and thus the glass fiber is evenly dispersed because the adhesive force between the filaments is broken.

At this time, the polyurethane foam resin stock solution has a relatively early initial reaction time of about 1 to 2 minutes of cream time (the time when creamy phenomenon of turbidity occurs when uniformly mixing isocyanate and polyol) than foaming immediately after mixing. Formulation is suitable. In this case, the foamed stock solution of late blending time is used to compress the glass fiber mat in the state of low viscosity of the foamed stock solution discharged to the top layer of the glass fiber mat to smoothly discharge the air contained between the glass filaments and to uniformly dispense the stock solution. For impregnation.

When foaming of the stock solution is started, stress should be minimized to the foam to be foamed, and the angle of the production line is adjusted so that the glass fiber mat is sufficiently raised along the foam stock solution. If air is left in the continuous glass fiber mat after impregnation or external stress is transmitted to the foam, it may cause cracks inside the foam.

When compressing the glass fiber mat through the foam controller (eg roller, plate) in this way, the foaming stock solution tends to be driven to the distal end of the width direction, so the compression degree of the foam controller should be properly adjusted. In this case, if the compression ratio is large, cracks are easily generated in the foam during foaming, and if the compression ratio is small, the upper surface of the foam is unevenly formed, and the foam is cured with air remaining inside the foam, and the foam is applied to the foam when the low temperature insulation is applied. Cracks are generated.

Therefore, the appropriate degree of compression of the foam regulator is appropriately locked out so that the foaming stock solution is visible on the upper surface of the glass fiber mat. In addition, if the pressurized state is so sustained that a compressive force of more than a reference is transmitted to the foaming stock solution, the stock solution is pushed to the rear of the foaming regulator at the time of pressurization, thereby causing interference with the newly ejected stock solution. Therefore, when the compression force of the foam controller is more than a certain pressure it should be adjusted to achieve a suitable impregnation state by a special floating device.

In the case of the discharge method, the foamed stock solution is preferably a traverse method of moving the discharge nozzle in the direction perpendicular to the continuous direction of the continuous line to discharge a certain amount of left and right on the glass fiber mat. The method of use can also be considered.

After impregnating the foam stock solution uniformly on the glass fiber mat, foaming is started at the stage of foaming. It is often checked whether the foam stock solution is evenly symmetrically expanded in the width direction, and the height is adjusted with the foam controller so that the upper surface of the foam is unevenly formed. Do not.

At this time, the free foaming of the foaming stock solution is excessively suppressed so as not to cause cracking or cracking inside the foam.

After the upper surface of the foam is formed evenly and foaming is completed, the condition of the conveyor is adjusted so that the foam is not physically stressed so that the foam is stabilized as much as possible during the curing process. Since the discharge amount, the conveyor speed and the ambient temperature are closely related, there is a method of accelerating curing through heating by installing a heating device on the lower surface of the conveyor.

In addition, since the surrounding environment during foaming has a great influence on the foaming characteristics of the foam, it maintains the ambient temperature of the foaming chamber at 20 to 30 ° C. to give optimum conditions for foam foaming.

As the upper and lower surface of the polyurethane foam, flexible products such as synthetic resin film, paper, asphalt paper, and metal film can be used, but in general, foamed foam using a release paper having reduced adhesiveness by releasing the paper or paper Can be prepared.

In this way, the foamed stock solution discharged onto the glass fiber mat is free-foamed through the upper open conveyor, cured and reaches the feed end, and the foamed foam is delivered to the transverse cutting device by the feed roller. This transverse cutting device cuts the cured foam to an appropriate size to produce a polyurethane foam composite with a face plate.

Polyurethane foam composite with the face material is cut to an appropriate size and used as a heat insulating material as it is, or can be used by attaching panels such as veneer plywood, aluminum plate, iron plate, gypsum board and the like on the upper and lower sides.

The surface-attached rigid polyurethane foam composite obtained in the present invention may be used as an insulator for an LNG transport vessel, an insulator for an LPG carrier ship, and the like.

According to the rigid polyurethane foam of the present invention manufactured in this way, even under ultra-low temperature below -165 ℃ cracks, shrinkage, torsion, etc. does not occur, and excellent mechanical properties such as tensile strength, compressive strength and excellent insulators of urethane It is possible to obtain a polyurethane foam for cryogenic insulation. In particular, the rigid polyurethane foam of the present invention is used as a cold insulation of the ship mainly to transport the cryogenic material with a lot of shaking and vibration has excellent thermal insulation and mechanical strength.

Hereinafter, the embodiment of the present invention will be described in detail in comparison with the comparative example.

"Part" and "%" are by weight unless there is particular notice in an Example and a comparative example below.

Comparative Example 1

As shown in Table 1, 100 parts of a polyol component having an average OH value of 370 to 460 (25 wt% of sorbitol + PO / EO, 40 wt% of phthalic anhydride + OH, 20 wt% of glycerin + PO / EO, pentaeryte Mixed polyol component consisting of 15% by weight of lithol + PO / EO), and 1.1 parts of water and 6 layers of glass fibers were used as the blowing agent. In addition, foaming and curing were carried out to prepare a sample of polyurethane foam using 175 parts of polymeric MDI having an average NCO% of 29 to 32 as an isocyanate component blended with the polyol component, and the results are shown in Table 1. .

Comparative Example 2

100 parts of polyol component having an average OH value of 370 to 460 (25 wt% of sorbitol + PO / EO, 30 wt% of phthalic anhydride + OH, 15 wt% of glycerin + PO / EO, and 30 wt% of pentaerythritol + PO / EO Mixed polyol component), 0.4 parts of water, 5 parts of HFC-365mfc and 6 layers of glass fibers were used as the blowing agent. In addition, foaming and curing were performed to prepare a sample of the polyurethane foam using 148 parts of an MCO having an average NCO% of 29 to 32 as an isocyanate component blended with the polyol component, and the results are shown in Table 1. .

Comparative Example 3

100 parts of a polyol component having an average OH value of 350 to 500 (10% by weight of sucrose + PO / EO, 20% by weight of pentaerythritol + PO / EO, 40% by weight of glycerin + PO / EO, toluenediamine + PO / Mixed polyol component consisting of 25% by weight of EO and 5% by weight of butanediol as a crosslinking agent, 0.4 part of water, 8 parts of CFC-11 (trichloromonofluoromethane) and 6 layers of glass fibers as foaming agents were used. Foaming and curing were carried out to prepare samples of rigid polyurethane foam using 115 parts of polymeric MDI with% 29-32.

Example 1

100 parts of a polyol component having an average OH value of 350 to 550 (34% by weight of sucrose + PO / EO, 25% by weight of sorbitol + PO / EO, and 35% by weight of phthalic anhydride + OH) and butanediol as a crosslinking agent 6% by weight), 1.1 parts of water and 7 layers of glass fibers as a blowing agent, 10% by weight of bromine-based flame retardant to increase the flame retardant, 3% by weight of fluorine-based nucleating agent to control the cell size, the average NCO% is 29 Foaming and curing were performed to prepare samples of rigid urethane foam using 124 parts of polymeric MDI with ˜32.

Example 2

100 parts of a polyol component having an average OH value of 350 to 550 (35% by weight of sucrose + PO / EO, 25% by weight of sorbitol + PO / EO, 35% by weight of phthalic anhydride + 35% by weight of butanediol as a crosslinking agent) 5% by weight), 1.1 parts of water and 6 layers of glass fibers as a blowing agent, 10% by weight of bromine-based flame retardant to increase the flame retardant, 3% by weight of fluorine-based nucleating agent to control the cell size, the average NCO% is 29 Foaming and curing were performed to prepare samples of rigid urethane foam using 124 parts of polymeric MDI with ˜32.

Example 3

100 parts of a polyol component having an average OH value of 350 to 550 (40% by weight of sucrose + PO / EO, 20% by weight of sorbitol + PO / EO, and 35% by weight of phthalic anhydride + OH) and butanediol as a crosslinking agent 5% by weight), 1.1 parts of water and 7 layers of glass fiber as the blowing agent, 10% by weight of bromine-based flame retardant to increase the flame retardant, 0.3% by weight of fluorine-based nucleating agent to control the cell size, the average NCO% is 29 Foaming and curing were performed to prepare samples of rigid urethane foam using 125 parts of polymeric MDI with ˜32.

The comparison result of the comparative example and the Example is shown in the "physical property" column of Table 1. The physical properties of Table 1 are determined as described below.

1.Free foam density: Foam density of foam foamed in injection foam into open box of plywood with internal dimension 200 × 200 × 200mm (kg / ㎥)

2. Density of product: Foam density of foam mixed with glass fiber as the density of product actually produced (kg / ㎥)

3. Thermal Conductivity: Measured using the Enter Thermal Conductivity Meter (Model No. 2031) (according to ASTM C-518).

4. Compressive strength: measured using Lloyd's universal testing machine at room temperature and ultra low temperature (according to ASTM D-1621)

5. Compression modulus: measured using Lloyd's universal testing machine at room temperature and ultra low temperature (according to ASTM D-1621)

6. Tensile strength: measured using Lloyd's universal testing machine at room temperature and ultra low temperature (according to ASTM D-1623)

7. Tensile modulus: measured using Lloyd's universal testing machine at room temperature and ultra low temperature (according to ASTM D-1623)

8. Flame retardant: Based on BS476 Part 7

9. Hygroscopicity: Based on KSM 3809

10. Low temperature impact test: Check for crack occurrence after immersion in liquid nitrogen for 1 hour (-195 ℃)

division ingredient Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Example 3 Polyol Sucrose + PO / EO - - 10 34 35 40 Pentaerythritol + PO / EO 15 30 20 - - - Glycerine + PO / EO 20 15 40 - - - Toluenediamine + PO / EO - - 25 - - - Sorbitol + PO / EO 25 25 - 25 25 20 Phthalic anhydride + OH 40 30 - 35 35 35 Crosslinking agent - - 5 6 5 5 blowing agent CFC-11 - - 8 - - - HFC-365mfc - 5 - - - - water 1.1 0.4 0.4 1.1 1.1 1.1 Textile reinforcement Fiberglass (ply) 6 6 6 7 6 7 additive Nuclear agent - - - 3 3 0.3 Flame retardant - - - 10 10 10 Isocyanate Polymeric MDI 175 148 115 124 124 125 Properties Free Foam Density (kg / ㎥) 110 109 106 110 108 112 Product density (kg / ㎥) 125 126 124 125 123 129 Thermal Conductivity (kcal / m · hr · ℃) 0.0310 0.0290 0.0212 0.0240 0.0239 0.0238 Compressive strength (kg / ㎠) 20 ℃ 10.6 10.7 7.8 13.26 13.77 14.28 -195 ℃ 20.7 19.6 19.7 22.44 22.95 22.64 Compression Modulus (kg / ㎠) 20 ℃ 453 462 220 509.9 550.7 520.1 -195 ℃ 709 691 614 892.6 923.1 908.3 Tensile Strength (kg / ㎠) 20 ℃ 21.2 20.6 8.0 25.49 27.02 26.61 -195 ℃ 26.4 24.5 13.4 30.59 32.02 31.51 Tensile Modulus (kg / ㎠) 20 ℃ 977 891 320 1325.6 1376.6 1356.3 -195 ℃ 1653 1406 519 2039.4 2192.4 2243.8 Low temperature shock Cracking Cracking Cracking No crack No crack No crack Moisture permeability coefficient (g / ㎡ · h) 2.6 2.5 2.7 2.5 2.4 2.4 Flame retardant clear clear clear clear clear clear

(Wherein PO: propylene oxide, EO: ethylene oxide, polymeric MDI: polymethylene polyphenyldiisocyanate, CFC-11: trichloromonofluoromethane, HCFC-141b: dichloromonofluoroethane, crosslinking agent: butanediol)

As can be seen from Table 1, in the case of Comparative Example 1 and Comparative Example 2 it can be seen that the thermal conductivity (0.0290 or more) of the product is significantly increased, the heat insulation is not good. In addition, the mechanical properties such as compressive strength and tensile strength are significantly reduced at room temperature and cryogenic temperature, such that problems such as cracking and scorch phenomenon may occur when used as a cryogenic insulator.

In addition, Comparative Example 3 shows excellent thermal insulation at a free foam density of 106kg / ㎥, but poor mechanical properties such as tensile strength. In particular, Comparative Example 3 shows poor physical properties under low temperature, such as cracking at an extremely low temperature of -165 ℃ or less, it can be seen that it is not suitable for the ultra low temperature attempted by the present invention.

In the case of Examples 1 to 3, not only has excellent heat insulating property by introducing a nucleating agent and a flame retardant, but also excellent mechanical properties such as tensile strength, compressive strength, tensile modulus, and compressive modulus. In particular, in the case of the embodiment of the present invention it can be seen that exhibits excellent mechanical properties without cracking under ultra-low temperature of -165 ℃.

Foams using non-fluorocarbon blowing agents have very low thermal insulation properties due to the high thermal conductivity of the blowing agents themselves. In particular, when only water is used as a blowing agent, aging (scorch) is likely to occur in the foam formed due to high reaction heat, and thus the mechanical strength is remarkably lowered. Thus, the flame retardant performance is poor due to the absence of fluorine-based components that exhibit fire extinguishing performance. This is a common phenomenon.

In the case of Examples 1 to 3, a nucleating agent was added to overcome this. As a result, the size of the cells was significantly reduced and the number of cells was increased, which greatly improved the thermal insulation performance. Also, the matrix between the cells was more firmly formed, and the mechanical strength was greatly improved. have.

In addition, instead of using the existing expensive flame retardant polyol component to improve the flame retardant performance, it was found that not only greatly improved the flame retardant performance but also suppressed the scorch phenomenon.

Therefore, as a result of Examples 1 to 3, the mechanical strength is better and the productivity is improved than the existing water-foaming system, and the thermal conductivity, which is one of the important characteristics of the polyurethane foam, is similar to or significantly inferior to HCFC-141b. It can be seen that it can be used as cryogenic insulation.

As mentioned above, although this invention was demonstrated by the limited Example, this invention is not limited by this and it is various in the range of equality of a common technical idea in the technical field to which this invention belongs, and a claim described below. Of course, modifications and variations are possible.

As described above, the present invention exhibits excellent mechanical strength, such as no cracking, while maintaining the excellent thermal insulation inherent in the rigid polyurethane foam even at very low temperatures without using a fluorocarbon blowing agent.

Claims (10)

Polyurethane foams produced by reacting a polyol component with an isocyanate component in the presence of a blowing agent, reaction catalyst and other additives, The polyol component may be (a) 15 to 35% by weight of a polyol obtained by adding propylene oxide and ethylene oxide to sorbitol, (b) 30 to 50% by weight of polyol obtained by adding propylene oxide and ethylene oxide to sucrose, (c A mixed polyol composition comprising 25 to 50% by weight of a polyol obtained by adding diethylene glycol or propylene glycol to phthalic anhydride; The isocyanate component is polymeric MDI having 2.6 to 3.0 functional groups; 80 parts by weight to 90 parts by weight of the mixed polyol composition is blended based on 100 parts by weight of the polymeric MDI; The blowing agent is used alone 0.5 to 2.0 parts by weight of water based on 100 parts by weight of the polyol component; The polyurethane foam is a rigid polyurethane foam, characterized in that containing 5 to 25 parts by weight of fiber reinforcement based on 100 parts by weight of the polyol component. The method of claim 1, Hard polyurethane foam, characterized in that the average OH value of the mixed polyol composition is 350 to 550, the average NCO% of the isocyanate component is 29 to 32. The method of claim 2, Hard polyurethane foam, characterized in that NCO / OH which is the ratio of NCO of the isocyanate component to OH of the polyol component is 1.0 ~ 1.3. The method of claim 3, wherein the mixed polyol composition is Hard polyurethane foam, characterized by further comprising 0 to 15 parts by weight of a crosslinking agent based on 100 parts by weight of the polyol component. 4. The fiber reinforcement of claim 3 wherein Hard polyurethane foam, characterized in that the glass fiber mat (CSM) containing a polyester binder of 5% by weight or less based on the weight of the fiber. The method of claim 5, wherein Hard polyurethane foam, characterized in that the glass fiber mat is contained 7 to 25 parts by weight based on 100 parts by weight of the polyol component. The method of claim 3, wherein Hard polyurethane foam, characterized in that it further comprises 5 parts by weight or less based on 100 parts by weight of the polyol component. The method of claim 3, wherein Hard polyurethane foam, characterized in that it further comprises up to 15 parts by weight of a flame retardant based on 100 parts by weight of the polyol component. Polyurethane foams produced by reacting a polyol component with an isocyanate component in the presence of a blowing agent, reaction catalyst and other additives, The polyol component may be (a) 15 to 35% by weight of a polyol obtained by adding propylene oxide and ethylene oxide to sorbitol, (b) 30 to 50% by weight of polyol obtained by adding propylene oxide and ethylene oxide to sucrose, (c A mixed polyol composition comprising 25 to 50% by weight of a polyol obtained by adding diethylene glycol or propylene glycol to phthalic anhydride; The isocyanate component is polymeric MDI having 2.6 to 3.0 functional groups; 80 parts by weight to 90 parts by weight of the mixed polyol composition is blended based on 100 parts by weight of the polymeric MDI; The average OH value of the mixed polyol composition is 350 to 550, the average NCO% of the isocyanate component is 29 to 32, and the NCO / OH, which is the ratio of NCO of the isocyanate component to OH of the polyol component, is 1.0 to 1.3; The blowing agent is used alone 0.5 to 2.0 parts by weight of water based on 100 parts by weight of the polyol component; The additive 5 parts by weight or less of nucleating agent and 15 parts by weight or less of flame retardant based on 100 parts by weight of the polyol component; The polyurethane foam is a rigid polyurethane foam, characterized in that containing 5 to 25 parts by weight of fiber reinforcement based on 100 parts by weight of the polyol component. Insulation material manufactured using the rigid polyurethane foam of claim 1 or claim 9.