KR20160023049A - Glass fiber reinforced polyurethane foam for keeping coldness at cyrogenic temperature - Google Patents

Abstract

The present invention relates to hard polyurethane foam and an insulating material using the foam. More particularly, the present invention relates to hard polyurethane foam which is environment-friendly and has excellent insulation properties, mechanical strength, and dimensional stability while exhibiting excellent insulation properties and mechanical properties at cryogenic temperature; and to the insulating material. The hard polyurethane foam maintains excellent insulation properties under cryogenic temperature and does not form cracks, while having excellent mechanical strength. The hardened polyurethane foam is prepared by curing a composition which comprises: a polyol component (A); an isocyanate component (B); a fiber reinforcing material (C); and a foaming agent (D) which includes methyl formate, an ester-based foaming agent.

Description

TECHNICAL FIELD [0001] The present invention relates to a glass fiber reinforced polyurethane foam for cryogenic cold storage of glass fiber reinforced polyurethane foam,

The present invention relates to a rigid polyurethane foam and a heat insulating material using the foam. More particularly, the present invention relates to a rigid polyurethane foam and a heat insulating material which exhibit excellent properties in environmental friendliness, heat insulation, mechanical strength and dimensional stability, and which exhibit excellent heat insulation and mechanical properties even under extremely low temperature conditions.

The polyurethane foam is usually obtained by reacting a polyol component and an isocyanate component in the presence of a foaming agent, a reaction catalyst and other additives.

Generally, polyurethane foam is very excellent in heat insulation and is widely used in refrigerator, building panel, refrigerator, cold storage, and low temperature warehouse. This is because the polyurethane foam is composed of independent bubbles having a diameter of 0.2 to 0.4 mm, and the foam material having excellent heat insulation performance is contained therein, which is excellent in the heat insulation property and the density can be controlled by controlling the amount and type of the foaming agent.

Conventional ultra low temperature polyurethane foams use dichloro monofluoroethane (HCFC-141b) as the hydrochlorofluorocarbon system or HFC-245fa or HFC 365/227 as the hydrofluorocarbon system as the blowing agent. HCFC-141b is a substance with an ozone depletion potential (ODP) of 0.11 and a global warming potential (GWP) of 630, which is already prohibited in the advanced countries for global environmental conservation in 1990 and Korea is also scheduled to be closed until 2030 . In addition, HFC blowing agent is used as a blowing agent to replace HCFC-141b. HFC blowing agent has ODP of 0, but GWP is very high. In fact, the GWP of HFC245fa is 1030 and HFC365 / 337 is 964. For this reason, the use of alternative foaming agents, which are low in GWP as well as ODP, has been constantly required. Cyclopentane (ODP 0, GWP 11) water (ODP 0, GWP 0) has been investigated as a blowing agent with ODP and GWP close to 0 or 0, but it has been used for polyurethane foam because of its low physical properties or explosion risk. This was difficult. For example, the insulation performance of cyclopentane is lower than that of HCFC-141b by 10%, which is not problematic. However, since it is flammable and explosive, it is reluctant to use it. Water reacts with the MDI to generate carbon dioxide, and carbon dioxide is trapped inside the urethane cell and expanded by the urethane reaction heat, so it is also used as a foaming agent. However, when 100% water alone is used as a blowing agent, the insulation performance is over 30%. To compensate for this, there is a problem that the thickness of the insulation material must be increased by 30% or more. For this reason, water is usually used in an amount of 0.1 to 1.0 wt% as an auxiliary foaming agent. The urethane cold insulator for ultra low temperature according to the present invention is a thermal insulation material for an LNG carrier. If the thickness of the thermal insulation material becomes thick, the weight of the ship becomes heavy and the capacity of the LNG storage tank becomes small. In case of the same capacity tank, Which causes the problem to be changed. For this reason, it has been demanded to develop a polyurethane system for cryogenic temperature using a new blowing agent which has ODP, GWP of 0, thermal insulation performance similar to that of HCFC-141b, Conventionally, urethane insulation performance was required to be 0.0290 W / mK or less based on thermal conductivity at room temperature. However, to maximize the storage capacity of LNG carrier ships, the insulation performance requirement level was significantly increased to 0.0260 W / mK or less based on room temperature thermal conductivity. Therefore, there is a need for a polyurethane insulation material using a new foaming agent and a polyurethane foam insulation material having improved heat insulation performance through the same.

It is an object of the present invention to provide a foaming agent containing a methylformate foaming agent having an ozone layer destruction index (ODP) of zero and a global warming coefficient of 1 or less as a foaming agent, Strength, dimensional stability, and the like, thereby providing a polyurethane foam satisfying the physical properties required as a heat insulating material for transporting LNG.

(B), a fiber reinforcing material (C) and a foaming agent (D), wherein the foaming agent (D) is an ester foaming agent such as methyl formate Wherein the polyurethane foam is a polyurethane foam.

The polyol component (A) comprises a polyester polyol and / or a polyether polyol.

The polyester polyol includes a benzene ring structure.

The isocyanate component (B) is a polymeric MDI having a functional group number of 2.6 to 3.0.

The average OH value of the polyol component (A) is 250 to 450 and the average NCO% of the isocyanate component (B) is 35% to 25%, or 29% to 32%.

(NCO / OH) of the isocyanate component (B) to OH of the polyol component (A) is 1.0 to 1.3.

The composition may further comprise a flame retardant, a plasticizer, a heat stabilizer and / or a surfactant.

The content of the fiber reinforcement (C) is 5 to 25 parts by weight based on 100 parts by weight of the polyol component (A).

The fiber reinforcing material may be glass fiber.

The present invention also provides a rigid polyurethane foam formed by reacting the composition and a heat insulating material comprising the foam.

The polyurethane foam of the present invention exhibits excellent mechanical strength such as excellent heat insulating property even at an extremely low temperature, and no crack is generated. In addition, the urethane foam of the present invention has an advantage of less environmental pollution and environmental friendliness by using an ester type foaming agent.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. On the other hand, the shape, size, scale or ratio of the elements in the drawings incorporated herein can be exaggerated to emphasize a clearer description.
BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a continuous production facility with an open-top conveyor for producing the rigid polyurethane foam of the present invention.

The terms or words used in the present specification and claims should not be construed to be limited to ordinary or dictionary terms and the inventor shall properly define the concept of the term in order to best explain its invention The present invention should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

The present invention relates to an environmentally friendly foaming agent having an ODP of 0 and a GWP of 1, a polyol component (A) capable of exhibiting excellent adiabatic performance with excellent miscibility and long-term storage stability with a foaming agent, an isocyanate component containing a polymeric MDI having a specific composition (B), and a rigid polyurethane foam formed from the composition, wherein the rigid polyurethane foam is excellent in heat insulation and mechanical properties even at an extremely low temperature. Hereinafter, the present invention will be described in detail.

The composition for forming a polyurethane foam according to the present invention comprises a polyol component (A) and an isocyanate component (B). In addition, the composition includes a fiber reinforcing material (C) for preventing shrinkage and maintaining high strength at a cryogenic temperature of the formed polyurethane foam. Further, the composition contains the blowing agent (D), the reaction catalyst and / or other additives within a predetermined content range. According to a specific embodiment of the present invention, the polyol component (A) may comprise a polyester polyol and / or a polyether polyol. In the present invention, the composition may further comprise additives such as a flame retardant, a plasticizer surfactant, and / or a stabilizer.

The polyol component (A) comprises a polyester polyol and / or a polyether polyol.

The polyester polyol is a polyester polyol obtained by reacting terephthalate phthalate and / or adipic acid with an aliphatic or aromatic alcohol such as diethylene glycol, diol, glycerol and / or triol Polyol or a mixture of two or more polyols. According to a specific embodiment of the present invention, the phthalic acid includes brominated phthalic acid, and the polyester polyol preferably includes a polyol obtained from bromic phthalic acid (hereinafter, brominated polyol). The brominated polyol contributes to improve the heat insulating performance of the polyurethane foam formed from the composition. In one specific embodiment of the present invention, bromophthalic anhydride can be used as the brominated phthalic acid. In addition, the composition according to the present invention may contain at least one polyol having a benzene ring structure. The polyol including the benzene ring contributes to enhancement of the strength and heat insulation performance of the polyurethane foam.

The polyether polyol is selected from the group consisting of ethylene glycol, 1,2-propane glycol, butylene glycol, 1,6-hexanediol, 1,8-hexanediol, 1-octanediol, neopentyl glycol, 2-methyl-1,3-propanediol, glycerol, trimethylolpropane, trimethylolpropane, 1,2,3-hexanetriol, 1,2,4-butanetriol, trimethylolmethane, pentaerythritol, Examples of the organic solvent include pentaerythritol, diethyleneglycol, triethylene glycol, polyethyleneglycol, tripropylene glycol, polypropyleneglycol, dibutylene glycol, But are not limited to, polybutyleneglycol, sorbitol, sucrose, hydroquinone, resorcinol, catechol, Bisphenols (bisphenol) ethylene oxide of at least one selected from the group consisting of, may be one prepared by polymerizing propylene oxide or by reacting a mixture of these. The polyether polyol preferably has a high polarity so that the adhesion between the polyurethane matrix and the fiber reinforcing material can be improved. For example, the polyether polyol is a polyol obtained by reacting sucrose.

According to a specific embodiment of the present invention, the polyol component (A) comprises a polyether polyol and a polyester polyol, wherein the polyether polyol comprises a brominated polyol containing a bromine (Br) atom and / Polyols. Preferably, the polyether polyol comprises a polyol comprising a brominated polyol and a benzene ring.

According to one specific embodiment of the present invention, the polyol component comprises 30 to 50 wt% of a polyol comprising a benzene ring, 20 to 40 wt% of a brominated polyol, and 20 to 40 wt% of a polyether polyol, based on 100 wt% By weight.

In the present invention, the isocyanate-based component (B) is a polymeric MDI having a functional group number of 2.6 to 3.0. Non-limiting examples of the polymeric MDI include hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (H12MDI), polyethylene polyphenyl isocyanate, toluene diisocyanate ), 2,2'-diphenylmethane diisocyanate (2,2'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI, monomeric MDI), polymeric MDI, orthotoluidine diisocyanate (TODI), naphthalene diisocyanate (NDI), xylene diisocyanate (XDI), lysine diisocyanate (LDI), triphenylmethane triisocyanate (TPTI), polymethylene polyphenyl diisocyanate, and any one or two or more selected from these may be used. Preferably, 4,4'-diphenylmethane diisocyanate (4,4'-MDI), polymeric diphenylmethane diisocyanate (polymeric MDI), or polyethylene polyphenyl isocyanate can be used.

On the other hand, the isocyanate component preferably has an average NCO% of 29% to 32%. If the NCO% of the isocyanate component is less than the above-mentioned range, the urethane foam is not crosslinked well and the foam strength is weakened. On the other hand, if it exceeds 32%, the viscosity becomes high and it is difficult to mix with polyol, and excessive crosslinking occurs, resulting in poor stability at a low temperature in a cryogenic condition. Therefore, the NCO% of the isocyanate component (B) is preferably from 29% to 32% to produce a stable rigid polyurethane foam.

According to a specific embodiment of the present invention, the polyol component (A) preferably has an average OH value of 250 to 450. [ If the average OH value does not fall within the above range, the strength of the urethane foam may be weakened, and the foam may be twisted or warped in the long term. On the other hand, if the average OH value is too high, cracking of the urethane foam may occur due to thermal shock at the cryogenic temperature.

In the composition according to the present invention, the reaction ratio of the polyol component (A) and the isocyanate component (B) is such that the ratio of NCO of the isocyanate to OH of the polyol is 1.0 to 1.3, preferably 1.15 .

If the ratio of NCO / OH is less than 1.0, unreacted OH remains, so that the resin strength is very low and shrinks. If the ratio of NCO / OH is more than 1.3, a large amount of unreacted NCO is left, so that the resin tends to be broken at an extremely low temperature due to an increase in the density of the foam and an NCO component which is not crosslinked with the polyol.

Therefore, if the blending ratio of the polyol component (A) and the isocyanate component (B) deviates from the above-mentioned range, the object of the present invention can not be achieved.

According to a specific embodiment of the present invention, the composition further includes a fiber reinforcing material for preventing shrinkage and maintaining high strength of the hard polyurethane foam at an ultra-low temperature of -165 DEG C or less. In particular, the insulation of the LNG carrier must not be cracked or shrunk during shaking or vibration of the ship during transportation, so that fiber reinforcement is required to further enhance the mechanical strength.

The fiber reinforcing agent is, for example, synthetic fibers such as glass fiber, polyamide, and polyester, and inorganic fibers such as carbon fiber and ceramic fiber. According to a specific embodiment of the present invention, the fiber reinforcing material may be glass fiber. The fibrous reinforcement may be included in an amount of 5 to 25 parts by weight or 10 to 20 parts by weight based on 100 parts by weight of the polyol component (A). If the content of the fiber reinforcing material is less than 5 parts by weight, the low temperature shrinkage stability and the effect of preventing cracks are lowered. On the other hand, if it exceeds 25 parts by weight, abnormal foaming of the foam during foaming of the polyurethane composition causes cracking of the foams and deterioration of heat insulation performance.

In the case of adding a fiber reinforcing material, for example, glass fiber, to the above composition in which the polyol component (A) and the isocyanate component (B) are mixed, it is particularly important to uniformly distribute the glass fiber. This is because the uniformity of the physical properties of the polyurethane foam can not be ensured unless the glass fiber is uniformly distributed in the foam.

According to a specific embodiment of the present invention, for this purpose, five or more layers of glass fiber mat laminates are successively fed to a conveyor having an open upper portion as described later, and the composition according to the present invention is evenly injected into the laminate, Thereby achieving a uniform distribution of the fibers. At this time, it is preferable that the glass fiber to be used is a continuous strand mat (CSM: Continuous Strand Mat) capable of continuous feeding when the polyurethane foam production system is continuous type.

In one specific embodiment of the present invention, the glass fiber mat laminate is formed by continuously supplying a plurality of glass fiber mat (about 90 m in length) on a conveyor and stacking them simultaneously as shown in Fig. The glass fiber mat laminate preferably has a laminate of 5 to 12 layers, preferably 6 to 10 layers of long-fiber mat.

The glass fiber mat is formed by bonding filaments of 25 占 퐉 or less with a polymer resin adhesive such as polyester powder in solid powder form. At this time, the amount of the polymeric resin adhesive is preferably minimized within a range in which the shape of the mat state is maintained. In the present invention, the content of the polymeric resin adhesive is 5% by weight or less, preferably 1.5 to 3% by weight based on the weight of the glass fiber.

When the content is more than 5% by weight, dissolution of the glass fiber between the glass fibers becomes difficult when the composition according to the present invention is foamed, so that the glass fiber is not uniformly dispersed and a high-quality foam can not be obtained. If the content is less than 1.5% by weight, bonding of the filaments is not sufficient and it is difficult to maintain the shape as a long-fiber mat.

Further, the composition according to the present invention further comprises a foaming agent (D). The foaming agent acts to form foam cells inside the insulation by generating gas during the polymerization process. Since the foaming agent exists in the cell formed of the polyurethane foam, it is advantageous to use a material having low thermal conductivity and high stability. Typical examples of foaming agents used in polyurethane foams include water, carboxylic acids, fluorocarbon based blowing agents, or inert gases such as carbon dioxide and air.

In the present invention, the foaming agent includes an ester-based foaming agent. The ester-based blowing agent has a low ozone layer destruction index and global warming index. Specifically, the ester-based foaming agent is methyl formate, and has an ozone depletion potential of 0, and a global warming index of 1, which is very low.

In the present invention, the foaming agent may further include an ester-based foaming agent alone or a physical foaming agent commonly used in forming a polyurethane foam in addition to the ester-based foaming agent. Examples of the physical foaming agent include 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,1,3,3-pentafluorobutane (HFC-365mfc) 1,3-pentafluoropropane (HFC-245fa), 1,1-dichloromonofluoroethane (HCFC-141b), 1-chloro-1,1-difluoroethane (HCFC-142b), chlorodifluoro Fluorocarbon based blowing agents such as chlorotetrafluoroethane (HCFC-22), dichlorotetrafluoroethane (CFC-114), chloroheptafluoropropane and dichlorohexafluoropropane, or methylal. It is not.

The content of the foaming agent in the composition according to the present invention is 3 to 15 parts by weight based on 100 parts by weight of the polyol component (A).

In the present invention, water (H ₂ O) may be further used as an auxiliary foaming agent, and its content is 0.1 to 1 part by weight, preferably 0.1 to 0.5 part by weight, relative to 100 parts by weight of the polyol component (A). If the content of water is less than 0.1 part by weight, the compressive strength and low-temperature dimensional stability are deteriorated. On the other hand, when the amount of water exceeds 1 part by weight, the thermal conductivity remarkably falls.

The reaction catalyst is generally used in the production of rigid polyurethane foam, and includes N, N'-dimethylethanolamine, N, N-dimethylcyclohexylamine, N, N, N ', N' Di (N, N-dimethylcyclohexylamine), and the like. These components may be used singly or in combination of two or more thereof. The reaction catalyst is 0.3 to 2 parts by weight, preferably 0.5 to 1 part by weight, based on 100 parts by weight of the polyol component (A).

Further, in the present invention, the composition may further comprise additives such as plasticizers, flame retardants, surfactants and / or stabilizers.

According to a specific embodiment of the present invention, the plasticizer comprises dioctyl phthalate. In addition, isopropylphenylphosphate, diisononylphthalate and the like can be used. The plasticizer has an effect of preventing occurrence of cracks due to impact under low temperature conditions. The plasticizer may contain 3 to 10 parts by weight relative to 100 parts by weight of the polyol component (A).

The flame retardant is added to enhance the flame retardancy of the rigid polyurethane foam according to the present invention. Examples of the flame retardant include tris (2-chloroethyl) phosphate, tris (chloropropyl) phosphate, tris (dipropyl) . The flame retardant is contained in an amount of 0.1 to 15 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the polyol component (A).

The surfactant controls the surface tension at the time of forming the foam cell to suppress the excessively large size of the foam cell and stabilizes the formation of the foam cell. The surfactant may be a polyalkylene glycol silicone copolymer as an organosilicon compound conventionally used in the production of a polyurethane foam. The content of the surfactant is 1.0 to 4.0 parts by weight, preferably 1.5 to 3.0 parts by weight, based on 100 parts by weight of the polyol component (A).

The stabilizer is added for compatibility, stability, and heat-resisting safety of the polyurethane foam, and specific examples thereof include alkylbenzene such as isopropylbenzene, but are not limited thereto. The stabilizer may be included in an amount of 1 to 10 parts by weight based on 100 parts by weight of the polyol component (A).

The present invention also provides a rigid polyurethane foam formed from the composition described above and a heat insulation material comprising the polyurethane foam.

The polyurethane foam obtained by the composition may have a thermal conductivity of 0.0260 W / mK or less. The thermal conductivity is a physical property that indicates the size of the thermal conductivity. The lower the thermal conductivity, the higher the thermal insulation performance. Since the rigid polyurethane foam exhibits not only flame retardancy but also excellent heat insulation property, a low thermal conductivity can be secured and the thermal conductivity can be maintained at 0.0260 W / mK or less, so that it can be utilized for architectural use, household appliance, automobile, and the like.

The polyurethane foam according to the present invention may have a closed cell ratio of about 80% or more, and preferably 90% or more. The polyurethane foam is made up of a small honeycomb-shaped cell, and the percentage of the cells that are cut out of the cells is called a closed cell ratio. The higher the closed cell ratio is, the better the heat insulating property is. When the closed cell ratio is less than about 80%, a certain level of heat insulating property may not be secured.

The rigid polyurethane foam according to the present invention has a density of 115 to 130 kg / m 3, a compressive strength of 12.0 kg / cm 2 or more, a compressive modulus of 450 kg / cm 2 or more, a tensile strength of 24 kg / And exhibits excellent mechanical properties with a tensile modulus of 1100 kg / cm 2 or more.

Next, a method for forming a rigid polyurethane foam from a composition for forming a rigid polyurethane foam according to the present invention will be described in detail. However, the method described below exemplifies a specific embodiment of the present invention, and the method of forming the polyurethane foam is not particularly limited thereto.

The rigid polyurethane foam is divided into a continuous type and an intermittent type mold depending on the manufacturing method.

Continuous foam is divided into upper open slab foam and upper and lower closed sandwich panel type. Upper open type is generally made by mixing a certain ratio of urethane composition in free foam form. By receiving relatively few, the foam structure has a uniform characteristic. Accordingly, the foam produced in this manner is cut to a certain size, and then panels such as plywood are attached to both sides or, as the case may be, the foam itself is used as an insulating material.

In addition, the intermittent mold foam is used as a heat insulating material for a product having a certain structure such as a refrigerator, a freezing container, a freezing panel by molding a urethane composition into a mold having a predetermined shape. Since the molded foam is once injected into a mold, no post-treatment such as cutting is required, so that there is an advantage that the loss is small and the productivity is high.

The hard polyurethane foam according to the present invention maintains low temperature characteristics such as prevention of shrinkage and generation of cracks even at an ultra-low temperature of -165 DEG C or lower, and is a continuous polyurethane foam which can be uniformly contained in a polyurethane foam, A method of applying the upper open slab foam production method can be applied. The polyurethane foam can be produced by a one-shot method, a prepolymer method, a spray method, and various other known methods depending on the method of reacting the raw material.

The one-shot method is a method in which all of raw materials such as an isocyanate component and a polyol component are simultaneously introduced and reacted. This one-shot method is simple and easy to work, but since the reaction occurs at a time, it is relatively difficult to control the reaction rate and there is a disadvantage that a large amount of reaction heat is generated and cracks may be generated in the foam.

On the other hand, the prepolymer method is a method in which a part of the polyol component is preliminarily reacted with the isocyanate component, followed by further reaction with another raw material. Therefore, this prepolymer method has a merit that the reaction is relatively gentle and the reaction rate is high, the foam viscosity rising rate due to the reaction is slow, and the complex structure can be filled in every corner, but the manufacturing step becomes long and the price can be increased exist.

In the present invention, the one-shot method can be used in consideration of workability, productivity, and cost. In this case, the polyol and the additive can be appropriately adjusted so that scorch and cracks in the foam due to a large amount of heat generation that may occur due to the reaction occurring at a time are not generated.

The foaming machine may use a high-pressure or low-pressure foaming machine commonly used in the polyurethane industry. The foaming conditions vary depending on the type of the foaming agent, but the temperature of the undiluted solution is usually from 18 to 25 DEG C and the discharge amount is preferably from about 30 to 80 kg / min.

If the initial reaction time is too late, the reaction time of the foam may be delayed and the productivity may be deteriorated. If the initial reaction time is too early, the viscosity may rise rapidly during foaming and the impregnation failure may occur in the glass fiber.

According to a specific embodiment of the present invention, the foam reaction time is preferably 100 to 200 seconds as an initial reaction initiation time and 400 to 600 seconds as an internal gelation time.

In addition, if the viscosity of the stock solution of the composition is high, impregnation of the fiber reinforcement with a fiber reinforcing material such as glass fiber is deteriorated and the fiber reinforcement is not uniformly distributed in the polyurethane foam after the completion of the foaming, thereby partially deviating the physical properties such as strength and density . Therefore, it is necessary to use a raw material having a low viscosity as much as possible. According to a specific embodiment of the present invention, the viscosity of the composition is 1500 cps or less at 25 캜.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a continuous production facility with an upper open conveyor belt for producing rigid polyurethane foam. Hereinafter, a method for producing a rigid polyurethane foam according to the present invention will be described in detail with reference to FIG.

First, the continuous production facility for producing the glass fiber-reinforced polyurethane foam of the present invention will be described with reference to the drawings. First, an upper open conveyor 3 having a side wall 5 of constant height and a bottom surface 4 of a certain width is provided. Unlike the conventional double conveyor, since the polyurethane foam is freely expanded, the upper open conveyor 3 can not control the glass height but the foam height in terms of ensuring the uniformity of the physical properties, which results in a production loss.

That is, in the case of the conventional double conveyor, since the height of the foam is controlled by the bottom surface and the ceiling of the conveyor, the production loss due to the cutting is small, but the foaming can not be performed freely.

Accordingly, the upper open conveyor according to the present invention is provided with a foam height regulator (not shown) for regulating the degree of compression of the foam on its feed end. Such a foam height regulator may have the form of a roller or a plate. In other words, by applying a compressive force to the raw foaming liquid before the gel time, which is the time at which the composition (foaming stock solution) has a viscosity, through the foam regulator provided at the feed end of the conveyor, the demand for ensuring the uniformity of foam height and physical properties is optimized .

A feed opening 1 for feeding a raw foaming solution in which a polyol component (A) and an isocyanate component (B) are mixed is provided at a feed end of the upper open conveyor 3, and a feed opening 1 for feeding a polyurethane foam top and bottom material A plurality of glass fiber mat feed rollers 2 for feeding the face material feed rollers 8 and 9 and the glass fiber mat are provided.

A conveying roller 6 is connected to the foam conveying end 12 of the upper open conveyor 3 and a transverse cutting device 7 is coupled to the end of the conveying roller 6.

The process for producing the rigid polyurethane foam of the present invention using the above-described continuous production equipment will be described in detail as follows.

The glass fiber mat laminate in a continuous state was supplied to the raw material feed end of the upper open conveyor and the composition according to the present invention as the raw material for foaming was uniformly mixed on the uppermost surface of the glass fiber mat laminate to adjust the line speed and the discharge amount The ejection opening 1 is moved to the left and right while the presentation liquid surface is ejected so as to coincide with the surface of the glass fiber mat. The glass fiber mat on which the foamed stock solution is sprayed is suspended in the foamed stock solution due to the free foaming of the foamed stock solution, so that the adhesive force between the filaments is broken and the glass fibers are evenly dispersed.

At this time, it is preferable that the initial foaming reaction is controlled to 100 seconds to 200 seconds. In the case of using the foamed raw material solution late in the early stage, the foamed foamed solution discharged on the uppermost layer of the glass fiber mat compresses the glass fiber mat in a low viscosity state to smoothly discharge the air contained in the glass fibers, It is to impregnate.

When starting foaming of the foaming stock solution, stress on the foams to be foamed is minimized and the angle of the production line is adjusted so that the glass fiber mat is sufficiently raised along the foaming stock solution. If the air remains in the continuous glass fiber mat after impregnation or external stress is transmitted to the foam, it may cause cracks inside the foam. Therefore, it is adjusted through the foam height adjuster so that the undiluted solution can be uniformly distributed.

Compressing the glass fiber mat through the foam height adjuster (eg, roller, plate) tends to cause the foam stock to be pushed to the widthwise ends, so that the degree of compression of the foam height adjuster should be properly adjusted. In this case, if the compression ratio is high, the foam tends to be cracked at the time of foaming. If the compression ratio is low, the upper surface of the foam is unevenly formed, so that air is left in the foam, Cracks are generated.

Therefore, a suitable degree of compression of the foam height regulator is suitable in a state in which the foaming stock solution is submerged so as to be slightly visible on the upper surface of the glass fiber mat. Further, when the pressurized state is maintained too long and a compressive force equal to or higher than the reference is transmitted to the foamed stock solution, the undiluted solution is pushed to the rear of the foam height adjuster at the time of pressurization, thereby causing interference with the newly discharged undiluted solution. Therefore, when the compression force of the foam regulator is higher than a certain pressure, it is necessary to adjust the impregnation state to be suitable by a special floating device.

In the case of the discharging method, it is preferable to discharge a predetermined amount of left and right to the glass fiber mat by a traverse method in which the discharging nozzle is moved in the direction perpendicular to the traveling direction of the continuous line, and a plurality of nozzles The method of use can also be considered.

It is confirmed from time to time whether the foamed stock solution foams symmetrically and evenly in the width direction in the step of starting foaming after uniformly infiltrating the glass fiber mat with the stock solution of foam, and the height of the foam is adjusted by the foam height adjuster to make the upper surface of the foam non- . At this time, care should be taken to avoid excessive free foaming of the foaming stock solution to prevent cracking or cracking in the foam.

Further, the condition of the conveyor is controlled so that the upper surface of the foam is uniformly formed and the foam is not physically stressed after the completion of the foaming, so that the foam is stabilized as much as possible during the curing. Since there is a close relationship between the discharge amount, the conveyor speed, and the ambient temperature, a heating device is installed on the lower surface of the conveyor to accelerate the curing through heating.

Also, since the surrounding environment at the time of foaming greatly affects the foaming characteristics of the foam, the ambient temperature of the foaming chamber is maintained at 20 - 30 캜 to give an optimum condition for foam foaming.

Flexible products such as synthetic resin films, paper, asphalt papers, and metal plate films can be used as the top and bottom faces of the polyurethane foam. However, in general, a foamed foam having a reduced adhesive property by being subjected to release treatment on paper or paper, Can be prepared.

Thus, when the foamed raw material discharged on the glass fiber mat is freely foamed through the upper open conveyor, hardened, and reaches the conveying end, the foamed foam is transferred to the transverse cutting device by the conveying roller. This transverse cutting device produces a polyurethane foam composite with facings by cutting the cured foam to an appropriate size. The polyurethane foam composite with this face material may be cut to a suitable size and used as a heat insulating material as it is, or a panel such as a veneer board, an aluminum plate, an iron plate, a gypsum board or the like may be attached to both upper and lower surfaces thereof.

The rigid polyurethane foam composite with a surface material obtained in the present invention can be used as a cold insulating material for a ship for transporting LNG.

According to the rigid polyurethane foam of the present invention thus produced, cracking, shrinkage and twisting do not occur even at an extremely low temperature of -165 DEG C or less, and excellent mechanical properties such as tensile strength and compressive strength, It is possible to obtain a polyurethane foam for a cryogenic insulator. In particular, the rigid polyurethane foam of the present invention is used as a cold insulating material of a ship which mainly carries cryogenic materials having many shakes and vibrations, and has excellent heat insulation and mechanical strength.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples. &Quot; part " and "%" are by weight unless otherwise specified in the following examples and comparative examples. The embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention.

Example

Examples 1 to 2

The polyol component was mixed with a foaming agent, a reaction catalyst, a plasticizer, and a flame retardant to prepare a mixed composition, and then polymeric MDi-i was added to the mixed composition to prepare a polyurethane-forming composition. The glass fiber mat laminate was continuously fed to a conveyor belt having an open top, and the composition was uniformly discharged onto the laminate to prepare a polyurethane foam continuously. The compositions of the respective components in Examples 1 and 2 are as shown in Table 1 below.

Comparative Examples 1 to 4

The polyol component was mixed with a foaming agent, a reaction catalyst, a plasticizer, and a flame retardant to prepare a mixed composition, and then polymeric MDi-i was added to the mixed composition to prepare a polyurethane-forming composition. The glass fiber mat laminate was continuously fed to a conveyor belt having an open top, and the composition was uniformly discharged onto the laminate to prepare a polyurethane foam continuously. The compositions of the respective components of Comparative Examples 1 to 4 are as shown in Table 1 below.

(Unit: g) division ingredient Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 ether
Polyol Consumption Toll + PO - - 20 20 30 30 Schross + PO 23 23 - - - - Glycerin + PO - - 20 20 - - Dipropylene glycol + PO - - 22 22 - - Pentaerythritol + PO - - - - 32 32 ester
Polyol Phthalate - - 20 20 20 20 Terephthalate 40 40 - - - - Phthalic Anhydride Bromide + DEG 20 20 Cross-linking agent 1,4 butanediol - - 5 5 5 5 Plasticizer Dioctyl phthalate 5 5 - - - - Flame retardant TCPP (g) 3 3 5 5 5 5 TEP (g) 3 3 Reaction catalyst Bis (N, N-dimethylcyclohexylamine) One One One One One One blowing agent HCFC-141b (g) - - 8 - - - HFC-245fa (g) - 4 - - 8 - Methyl formate (g) 6 3 - 6 - 6 Water (g) 0.2 0.2 0.4 0.2 0.4 0.2 Fiber reinforcement Glass fiber (glass fiber mat, CSM) 15 15 15 15 13 13 Hardener Polymeric MDI (kg) 120 120 115 115 125 125

PO: propylene oxide, DEG: diethylene glycol, polymeric MDI: polymethylene polyphenyl diisocyanate, HCFC-141b: 1,1-dichloromonofluoroethane, HFC-245fa: 1,1,1,3,3- Fluoropropane, TCPP: tris chloropropyl phosphate, TEP: triethyl phosphate

Comparative experiment

As shown in the following Table 2, Comparative Example 1 exhibits excellent heat insulation at a free foaming density of 110 (kg / m 3) to 0.0240 (W / mK) and is excellent in mechanical properties such as tensile strength and used for insulation of LNG tank tanks However, it can not be applied to regulation of HCFC-141b at present. Comparative Example 2 is similar to HCFC-141b in that the foaming agent is replaced with methyl formate only in the blowing agent under the same density condition as Comparative Example 1, but the mechanical strength such as compressive strength is lowered, the flame retardancy is poor, and the dimensional stability is poor And it is not suitable for cryogenic temperature.

In Comparative Example 3, as in Comparative Example 1, HFC-245fa used as a foaming agent has a high global warming index and is a substance to be regulated in the future and has a low boiling point of 15 DEG C Urethane foam does not occur uniformly, and thus there are disadvantages that defects are often generated during the production of cryogenic insulation. In Comparative Example 4, HFC-245fa was replaced with methyl formate only in the foaming agent under the same conditions as in Comparative Example 3, and mechanical strength was lowered, low-temperature shrinkage occurred, and cracking occurred during thermal shock, Can not reach the physical properties of

Also, as shown in Comparative Examples 2 and 4, when the foaming agent is changed from methylene formate to HCFC-141b or HFC-245fa, the strength is lowered, the dimensional stability is weakened, and the heat insulating performance is lowered. This is because methyl formate has the characteristic of softening the foam and roughening the cell. In addition, the adhesive force between the urethane foam and the glass fiber is lowered, so that the tensile strength is remarkably lowered and cracks are generated at a low temperature.

On the other hand, Examples 1 to 2 have excellent heat insulating properties and excellent mechanical properties such as tensile strength, compressive strength, tensile elastic modulus and compressive modulus. Particularly, in the case of the embodiment of the present invention, it can be seen that excellent mechanical characteristics are exhibited without causing cracking at an ultra-low temperature of -165 DEG C or less. Further, as shown in Examples 1 to 2, it was found that not only methyl formate alone but also methyl formate and HFC-245fa were used as the foaming agent, have.

As described above, the rigid polyurethane foam according to the present invention comprises a polyol component having two or more hydroxyl groups and having an average OH value of 250 to 450, a polyisocyanate component having at least two isocyanate groups, a blowing agent, a catalyst, and the like By mixing a mixture of additives and adding a fiber reinforcing material such as glass fiber, it has high strength and excellent low temperature dimensional stability even at an ultra-low temperature of -165 DEG C or less, while maintaining excellent heat insulation characteristic of general rigid polyurethane foam.

In the polyurethane foam according to the present invention, the adhesion between the urethane matrix and the glass fiber was increased by using a polyol having a high polarity, and the strength and the heat insulating performance of the foam were improved by introducing a polyester polyol having a benzene ring structure, The terephthalic acid polyol was used to maximize the heat insulation performance. Further, the inclusion of dioctyl phthalate prevented cracking due to impact even at low temperature conditions.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Free Foam Density (kg / m3) 107 107 110 108 112 110 Product density (kg / m3) 122 124 126 125 127 126 Thermal conductivity (W / mK) 0.0250 0.0255 0.0285 0.0283 0.0290 0.0288 Compressive strength (N / cm2) 1.34 1.31 1.32 1.28 1.29 1.24 Compressive modulus (N / cm 2) 55.0 53.2 48.5 47.8 49.0 48.2 Tensile strength (N / cm2) 2.8 2.7 2.7 2.6 2.7 2.6 Tensile modulus (N / cm2) 148 152 128 127 130 128 Cold shock (crack) clear clear clear clear clear Cracking Flammability B2 B2 B3 B3 B3 B3 Dimensional stability clear clear clear Contraction clear Contraction

On the other hand, the physical properties in Table 2 are determined as described below.

1. Free Foam Density: Foam density of foam injected into an open box of plywood with internal dimensions of 200 x 200 x 200 mm (kg / m 3)

2. Product Density: Foam density (kg / m3) of a foam mixed with glass fiber foamed with a foaming machine in an upper open box with an internal dimension of 1,000 × 1,000 × 600 mm.

3. Thermal Conductivity: Measured using anacon thermal conductivity meter (Model No. TCA POINT 2) (according to ASTM C-518)

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

5. Compressive modulus: Measured using a universal tester from Weed Lab at room temperature and cryogenic temperature (according to ASTM D-1621)

6. Tensile strength: Measured using a universal tester of Weed Lab at room temperature and cryogenic temperature (according to ASTM D-1623)

7. Tensile modulus: Measured using a universal tester from Weed Lab at room temperature and cryogenic temperature (according to ASTM D-1623)

8. Flammability: Based on DIN 4102 B2

9. Low temperature impact test: After immersing in liquefied nitrogen for 1 hour, check for cracks (-195 ℃)

1: outlet 2: glass fiber mat
3: upper open conveyor 4: bottom surface
5: Side wall 6: Feed roller
7: transverse cutting device 8, 9: upper and lower face plates

Claims (12)

Wherein the foaming agent (D) comprises a polyform component (A), an isocyanate component (B), a fiber reinforcing material (C) and a foaming agent (D) / RTI >
The method according to claim 1,
Wherein the polyol component (A) comprises a polyester polyol and / or a polyether polyol.
3. The method of claim 2,
Wherein the polyester polyol comprises a benzene ring structure.
The method according to claim 1,
Wherein the isocyanate component (B) is a polymeric MDI having a functional group number of 2.6 to 3.0.
The method according to claim 1,
Wherein the polyol component (A) has an average OH value of 250 to 450 and an average NCO% of the isocyanate component (B) is 29% to 32%.
The method according to claim 1,
(NCO / OH) of the isocyanate component (B) to OH of the polyol component (A) is 1.0 to 1.3.
The method according to claim 1,
Wherein the isocyanate component (B) has an average NCO% of 25% to 35%.
The method according to claim 1,
Wherein the composition further comprises a flame retardant, a plasticizer, a heat stabilizer and / or a surfactant.
The method according to claim 1,
Wherein the content of the fiber reinforcing material (C) is 5 to 25 parts by weight based on 100 parts by weight of the polyol component (A).
The method according to claim 1,
Wherein the fiber reinforcing material is glass fiber.
A rigid polyurethane foam formed by reacting a composition according to any one of claims 1 to 10.
A heat insulating material comprising the rigid polyurethane foam according to claim 11.

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