KR20160023050A - A high flame retarding polyurethane foam using a foaming agent of methylformate and a insulator comprising the same - Google Patents

Abstract

The present invention relates to a composition for forming a polyurethane foam, a polyurethane foam formed from the composition, and an insulator comprising the polyurethane foam. More particularly, the present invention relates to a hardened polyurethane foam which uses an environment-friendly foaming agent and has excellent insulating property, dimensional stability, adhesive strength, and particularly, fire retardant property, and to an insulator comprising the same. The polyurethane foam according to the present invention has high fire retardant property while maintaining remarkable insulating property, and does not generate contraction or modification at low temperature while exhibiting excellent mechanical strength.

Description

TECHNICAL FIELD The present invention relates to a thermoplastic polyurethane foam using a methylformate foaming agent and a heat insulating material containing the foamed polyurethane foam,

The present invention relates to a composition for forming a polyurethane foam, a polyurethane foam formed from the composition, and a heat insulating material comprising the polyurethane foam. More particularly, the present invention relates to a rigid polyurethane foam which is excellent in heat insulation, dimensional stability, adhesive strength, especially flame retardant property, and an insulating material containing the foam, using an environmentally permissive foaming agent.

Polyurethane foam can be manufactured as panel and spray type, easy to control the thickness, easy to be assembled or sprayed on site, air is short and insulation is excellent, Although it is widely used in refrigerated warehouses and various types of shops, it is vulnerable to fire. In order to overcome this problem, a polyol obtained by reacting urethane structure with diethyl glycol with phthalic anhydride as a polyol to convert PIR into heat resistant PIR and maximize flame retardancy was mainly used. Dichloromonofluoroethane (HCFC-141b) was used as the foaming agent, and HFC-245fa or HFC 365/227 was used as the hydrofluorocarbon type. The HCFC-141b is a substance with an ozone depletion potential (ODP) of 0.11 and a global warming potential (GWP) of 630, so developed countries are already prohibited from being used in the early 1990s for global environmental conservation 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) was investigated as a blowing agent with ODP and GWP close to 0 or 0. Cyclopentane itself has a flammable, explosive urethane foam It is not suitable for production and it is not compatible with polyol used for making PIR foam, and it has a disadvantage that long-term storage stability is poor and physical properties are changed, so it is difficult to apply to urethane foam which requires high hardness. Also, when water alone is used as the blowing agent, the foam tends to be crumbled, the adhesion to the surface of the foam is deteriorated, and the heat insulating performance deteriorates, making it unsuitable for a urethane panel or spray for insulation. Therefore, there is a need for a technique for manufacturing a highly flame retardant polyurethane foam insulation using a new blowing agent.

It is an object of the present invention to provide a blowing agent having a zero ozone layer destruction index (ODP) of zero and a global warming coefficient of 1 or less, , Mechanical strength, dimensional stability, and the like, thereby providing a polyurethane foam satisfying the physical properties required as a panel for construction, a panel for freezing and cold storage, and a spray insulation. Other objects and advantages of the present invention will become apparent from the following description. It is also to be easily understood that the objects and advantages of the present invention can be realized by the means or method described in the claims, and the combination thereof.

The present invention provides a polyurethane foam of high hardness and a foam-forming composition for producing the polyurethane foam. The composition for forming a polyurethane foam comprises a polyol component (A) and an isocyanate component (B) comprising a polyester polyol and / or a polyether polyol, and a foaming agent, wherein the foaming agent comprises methyl formate. Further, in the present invention, the polyol component (A) includes a Mannich-type polyol.

Here, the Mannich type polyol is a phenol type polyol having a hydroxyl value of 300 to 400.

The content of the Mannich-type polyol is 10% by weight to 30% by weight based on 100% by weight of the polyol component (A).

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 150 to 400, and the average NCO% of the isocyanate component (B) is 29% to 32%.

(NCO / OH) of the isocyanate component (B) to OH of the polyol component (A) is 1.5 to 4.0.

The content of the blowing agent is 5 to 20 parts by weight based on 100 parts by weight of the polyol component (A).

Also, the composition may further contain 0.5 to 3 parts by weight of water as a foaming aid, relative to 100 parts by weight of the polyol component (A).

The composition may further comprise a reaction catalyst within a range of 0.5 to 5 parts by weight based on 100 parts by weight of the polyol component (A).

Meanwhile, the composition may further include a flame retardant, a crosslinking agent, a heat stabilizer, and / or a surfactant.

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

The polyurethane foam according to the present invention exhibits excellent mechanical strength such that it maintains excellent heat insulating properties while having high hardenability and does not cause shrinkage or deformation at low temperatures. In addition, the polyurethane foam according to the present invention has an ozone layer destruction index of 0, and is environmentally friendly when manufactured and used by using a blowing agent having a global warming index of 1.

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 capable of exhibiting excellent adiabatic performance with excellent miscibility and long-term storage stability with a foaming agent, a polymeric MDI having a specific composition as an isocyanate component, And a reaction catalyst and other additives, and a rigid polyurethane foam excellent in heat insulation and mechanical properties even at an extremely low temperature formed from the composition.

The polyurethane foam according to the present invention is obtained by mixing a polyisocyanate component (A) having an average OH value of 150 to 400 with a polyisocyanate component (B) having at least two isocyanate groups and a foaming agent, having two or more hydroxyl groups, It has the flame retardant performance more than the flame retardant material specified in KS ISO 5660-1 or the flame retardant performance higher than the B2 level of DIN 4102 PART 1 while maintaining excellent heat insulation characteristic of general hard polyurethane foam by reacting, And excellent dimensional stability.

The composition for forming a polyurethane foam according to the present invention comprises a polyol component (A) and an isocyanate component (B) and a blowing agent. According to a specific embodiment of the present invention, the polyol component (A) may comprise an ester polyol and / or an ether polyol. In one embodiment of the present invention, the foaming agent is an ester-based foaming agent, and the ester-based foaming agent is, for example, methyl formate. The composition according to the present invention may contain a nitric polyol as a polyol component.

Hereinafter, the composition according to the present invention will be described in detail.

According to the present invention, the polyol component (A) comprises a polyester polyol and / or a polyether polyol.

The polyester polyol is obtained by reacting terephthalate phthalic anhydride and / or adipic acid with a diol such as an aliphatic or aromatic alcohol such as diethylene glycol, glycerol and / or triol One polyol or a mixture of two or more polyols. According to a specific embodiment of the present invention, the polyester polyol preferably comprises at least one polyol having a benzene ring structure. According to a specific embodiment of the present invention, the polyol having a benzene ring structure has a hydroxyl value of 200 to 400. In addition, the polyester polyol may further include a polyol obtained by reaction with adipic acid. The polyol obtained by the reaction with adipic acid preferably has a hydroxyl value of 50-100.

The polyether polyol preferably has a hydroxyl value of 300 to 500 and may be selected from the group consisting of ethylene glycol, 1,2-propane glycol, butylene glycol, 1,6- 1,6-hexanediol, 1,8-oxtanediol, neopentyl glycol, 2-methyl-1,3-propanediol, propanediol, glycerol, trimethylolpropane, 1,2,3-hexanetriol, 1,2,4-butanetriol (1,2,4-hexanetriol) butanetriol, trimethylolmethane, pentaerythritol, diethyleneglycol, triethylene glycol, polyethyleneglycol, tripropylene glycol, polypropylene glycol polypropyleneglycol, dibutylene glycol, polybutyleneglycol, sorbitol, sucrose, hydroxycarboxylic acid, Quinone (hydroquinone), resorcinol (resorcinol), catechol (catechol), and ethylene at least one selected from the group consisting of bisphenol (bisphenol) oxide, propylene oxide or by reacting a mixture thereof may be one prepared by polymerizing.

In addition, the polyol component (A) may include a Mannich base polyol. The mannich polyol is formed by alkoxylating a Mannich condensation product of an alkanolamine such as phenol or substituted phenol, formaldehyde and diethanolamine. The Mannich type polyol serves to improve the flame retardancy and compressive strength of the polyurethane foam. In particular, the Mannich type polyol having a functional group number of 5 or more has excellent properties of reactivity and adhesiveness, and in case of the polyurethane foam containing the same, the adhesion property to the adhered surface is improved. According to a specific embodiment of the present invention, the Mannich-type polyol may have a phenol structure or a substituted phenol structure, and the Mannich-type polyol having the phenol structure is more effective in improving the flame retardant property of the polyurethane foam . In the Mannich type polyol having the phenol structure, it is more preferable that the hydroxyl group is 300 to 400.

The mannich type polyol comprises 10% by weight to 30% by weight based on 100% by weight of the polyol component (A). When the content of the Mannich base polyol is less than 10% by weight, the strength and flame retardancy of the formed polyurethane foam are lowered. On the other hand, if the content exceeds 30% by weight, the reaction becomes abnormally faster and the amount of catalyst required to achieve the desired reaction profile is less than the proper amount. When the amount of catalyst is less than the proper amount, Or the flame retardancy may be damaged.

According to one specific embodiment of the present invention, the polyol component (A) comprises a polyether polyol, a polyester polyol and a Mannich polyol, wherein the polyester polyol comprises at least one polyol containing a benzene ring. Wherein 45 to 75% by weight of a polyester polyol, 10 to 30% by weight of a mannich type polyol and 10 to 40% by weight of a polyether polyol are contained based on 100% by weight of the polyol component (A).

In the composition according to the present invention, the isocyanate 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 TDI), 2,2'-diphenylmethane diisocyanate (2,2'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 4,4'- (MDI), polymeric MDI, polymeric MDI, orthotoluidine diisocyanate (TODI), naphthalene diisocyanate (NDI), xylene diisocyanate (XDI), ricinDi Isocyanate (LDI), triphenylmethane triisocyanate (TPTI), and polymethylene polyphenyl diisocyanate. Any one or two or more selected from these may be used. Preferably, polymeric diphenylmethane diisocyanate (polymeric MDI) or polyethylene polyphenyl isocyanate may 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.

In the present invention, it is preferable that the polyol component (A) has an average OH value of 150 to 400. 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, the PIR is not achieved well and the desired flame retardant performance is hardly achieved.

In the composition according to the present invention, the reaction ratio of the polyol component (A) to the isocyanate component (B) is from 1.5 to 4.0, preferably from 1.7 to 3.5, the ratio of NCO of isocyanate to OH of polyol .

When the ratio of NCO / OH is less than 1.5, the flame retardant performance is lowered. On the other hand, when the ratio of NCO / OH is more than 4, the strength of the foam is lowered and the foam is easily broken. . Therefore, if the blending ratio of the polyol component and the isocyanate component to be reacted with the polyol component is out of the above range, the object of the present invention can not be achieved.

Further, the composition according to the present invention comprises a foaming agent. Generally, the foaming agent acts to form a foam cell inside a heat insulating material by generating gas during the polymerization process. Since the foaming agent is present in the cell after polyurethane foam is formed, 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. HFC-245fa or HFC 365/227 was used as the low-temperature polyurethane foam in the hydrochlorofluorocarbon system as the blowing agent, and dichlorofluoromethane (HCFC-141b) as the blowing agent, and HFC 365/227 as the hydrofluorocarbon system. ODP) of 0.11, and Global Warming Index (GWP) of 630, which are prohibited or prohibited in each country. In addition, the HFC blowing agent has an ODP of 0 but has a very high GWP, which is very high in environmental risk. 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.

The composition according to the present invention is characterized by containing 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 addition, the foaming agent may further include a physical foaming agent commonly used in polyurethane foam formation in addition to the ester-based foaming agent. Examples of the physical foaming agent include 1,1,1,3,3-pentafluorobutane (HFC-365mfc), 1,1,1,3,3-pentafluoropropane (HFC-245fa) Fluorocarbons such as 1-dichloromonofluoroethane (HCFC-141b), chlorodifluoroethane (HCFC-22), dichlorotetrafluoroethane (CFC-114), chlorheptafluoropropane, dichlorohexafluoropropane, Based foaming agent or methylal, but is not particularly limited thereto.

The content of the foaming agent in the composition according to the present invention is 5 to 20 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 0.5 to 3 parts by weight, preferably 1 to 2 parts by weight, based on 100 parts by weight of the polyol component (A). If the content of water is less than 0.5 parts by weight, the compressive strength and the low-temperature dimensional stability are deteriorated. On the other hand, when the amount of water exceeds 3 parts by weight, the thermal conductivity remarkably decreases.

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 used in an amount of 0.5 to 5 parts by weight, preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the polyol component (A).

Further, in the present invention, the composition may further contain additives such as a flame retardant, a surfactant, a crosslinking agent, and a stabilizer.

The flame retardant is added in order 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 (dipropoxy) . The flame retardant is contained in an amount of 5 to 20 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. In the present invention, the surfactant may be a polyalkylene glycol silicone copolymer as an organosilicon compound commonly 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 cross-linking agent is used to improve the strength of the polyurethane foam, and known materials used in the production of polyurethane foam can be used. Specific examples thereof include ethylene glycol, propylene glycol, butanediol, and glycerin. Or more may be mixed and used. However, the present invention is not limited thereto. The crosslinking agent is contained in an amount of 0 to 10 parts by weight, preferably 0 to 5 parts by weight, based on 100 parts by weight of the polyol component (A). Here, when the amount of the additive is 0 parts by weight based on 100 parts by weight of the polyol component, it means that the additive is not used.

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 contained in an amount of 1 to 10 parts by weight, preferably 1 to 3 parts by weight, based on 100 parts by weight of the polyol component (A).

The present invention also provides a polyurethane foam formed from the composition described above. The polyurethane foam obtained by the above composition may have a thermal conductivity of 0.0220 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 together with the Mannich polyol and the flame retardant exhibits not only flame retardancy but also excellent heat insulation property, a low thermal conductivity can be ensured and the thermal conductivity can be maintained at 0.0220 W / mK or less. 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.

Further, the polyurethane foam according to the present invention exhibits excellent mechanical properties with a compressive strength of 1.5 kg / cm ² or more and a density of 30 to 50 kg / m ³ .

Next, a method for producing the rigid polyurethane foam according to the present invention will be described with reference to specific examples.

The polyurethane foam according to the present invention can be prepared by reacting the aforementioned polyol component and isocyanate component as basic raw materials in the presence of a foaming agent, a reaction catalyst and other additives.

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 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. The prepolymer method has a merit that the reaction is relatively gentle and the reaction rate is high and the foam viscosity rise rate due to the reaction is slow so that the complex structure can be filled everywhere, but the manufacturing step becomes long and the price can be increased.

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.

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.

Also, if the viscosity of the stock solution of the composition is high, there may be a partial variation in 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.

The above-described method of producing a foam is very useful for producing a continuous sandwich panel, an intermittent panel, and an insulation material through spraying or field foaming.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples. However, 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. "Part" and "%" are by weight unless otherwise specified in the following examples and comparative examples.

Example

Examples 1 to 2

A mixture of polyether polyol, polyester polyol and Mannich polyol was used as the polyol component. The polyol component was mixed with a foaming agent, a reaction catalyst, a flame retardant, a crosslinking agent, a stabilizer, and a surfactant to prepare a mixed composition. The mixed composition was mixed with Polymeric MDI and foamed at the production site of a continuous sandwich panel to prepare a urethane foam. The compositions of the respective components in Examples 1 and 2 are as shown in Table 1 below.

Comparative Examples 1 to 4

A mixture of a polyether polyol and a polyester polyol was used as the polyol component. The polyol component was mixed with a foaming agent, a reaction catalyst, a flame retardant, a crosslinking agent, a stabilizer, and a surfactant to prepare a mixed composition. The mixed composition was mixed with Polymeric MDI and foamed at the production site of a continuous sandwich panel to prepare a urethane foam. 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 Sorbitol + PO - - 10 10 Ethylenediamine + PO - - - - 10 10 Schross + PO 10 10 10 10 Toluene diamine + PO - - 10 10 Mannich
Polyol Mannich polyol
(RB-214) - 15 Phenolic polyol
(JH-3766) 15 - - - ester
Polyol Phthalate - - 10 10 25 25 Terephthalate 25 25 30 30 - - Adipate 15 20 20 20 Cross-linking agent glycerin 3 - stabilizator Isopropylbenzene 3 5 - - - - Flame retardant TCPP 12.5 11 13 13 13 13 Surfactants silicon 1.5 1.5 1.5 1.5 1.5 1.5 Reaction catalyst PMDETA / DABCO TMR
mixture 3.5 3.5 3 3 5 5 blowing agent HCFC-141b - - 17 0 25 - Methyl formate 10 8 - 10 - 15 water 1.5 1.0 1.1 1.1 0.7 0.7 Hardener Polymeric MDI 160 110 160 160 110 110

PO: propylene oxide, polymeric MDI: polymethylene polyphenyl diisocyanate, HCFC-141b: 1,1-dichloromonofluoroethane, TCPP: tris chloropropyl phosphate,

Property evaluation

As shown in the following Table 2, Comparative Example 1 exhibits excellent heat insulation at a free foam density of 38 (kg / m 3) to 0.0190 (W / mK), and satisfactory mechanical properties such as compressive strength and low- However, it can not be exported to some countries due to the regulation of the blowing agent. If the regulation of the domestic blowing agent is severe, it will be difficult to use it within 5 years. Comparative Example 2 was obtained by replacing HCFC-141b with methylformate only in the blowing agent under the same density condition as Comparative Example 1, and the heat insulating performance was similar to that of HCFC-141b, but the compressive strength was lowered and the low temperature stability stability was remarkably decreased. It is not suitable as a PIR panel for construction.

In Comparative Example 3, as in Comparative Example 1, the thermal insulation performance was similar in spraying, but the compressive strength and dimensional stability were inferior and it was found to be unsuitable for flame retardant spraying.

Also, as shown in the results of Comparative Examples 2 and 4, when the foaming agent is changed from HCFC-141b to methyl formate in conventional architectural PIR panels or high-hardness spray foams, severe foam shrinkage occurs and strength is lowered, Flame retardancy also falls. This is because the methyl formate softens the foam and roughens the cell and is flammable. To overcome this and to reach the target properties, the polyol component used should be changed and additives should be used.

In Examples 1 and 2, a polyester polyol and a polyether polyol having a benzene ring structure were used to enhance the heat insulation performance and flame retardancy, and heat resistance was further enhanced by using isopropylbenzene as a stabilizer. Further, the foam strength was enhanced by using glycerin as a crosslinking agent. In addition, the application of the PIR panel for architectural use (Application Example 2) was applied to the spraying of hard-to-run spray (Example 2), in which the ratio of the mixture of polymeric MDI and other components was fixed at 110: 100, Mannich polyol was used to enhance the flame retardant performance and adhesion to the adherend surface.

As can be seen from the following Table 2, in the case of Examples 1 and 2, compression strength, dimensional stability, and flame retardancy were not lowered compared to HCFC-141b as well as thermal insulation performance even when methylformate was used as the foaming agent. It can be seen that it is applicable for PIR panel or spray.

The foaming agent for HFCs such as HFC-245fa, HFC-365mfc and HFC-365/227 mixture as foaming agent is not limited to the insulating properties of the foaming agent itself, compatibility with the polyol and solubility with the polyol, Since methyl formate is more advantageous than methyl formate in the present invention, methyl formate can be used instead of methyl formate in the applicable formulations.

The rigid polyurethane foam according to the present invention has excellent flame retardant performance, excellent mechanical properties such as compressive strength, and excellent heat insulating property inherent to urethane. In particular, the rigid polyurethane foam of the present invention can be used for continuous or intermittent panels, building panels, thermal insulation, etc., and is also applicable to field foam urethane foam such as spray or field injection.

ingredient Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Free Foam Density (kg / m3) 38 29 38 37.5 28 28 Product density (kg / m3) 44 34 44 43.5 34 34 Thermal conductivity (W / mK) 0.019 0.019 0.019 0.020 0.019 0.020 Compressive strength (N / cm2) 2.6 2.2 2.5 2.1 2.2 1.8 Low Temperature Dimensional Stability (Δv%) -0.3 -0.5 -0.5 -5.5 -0.7 -12.5 Flammability (KS) Quasi-fire - Quasi-fire Flame retardant material - - Flammability (DIN) - B2 - - B2 B3

The physical property evaluation is 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 KS-ISO 5660-1 (PIR panels for construction) or DIN 4102 B2 (Spray)

9. Low-temperature dimensional stability: Measurement of dimensional change rate after 72 hours in -40 ℃ CHAMBER

Claims (13)

A polyol component (A), an isocyanate component (B) and a foaming agent,
The polyol component (A) comprises a polyester polyol and / or a polyether polyol,
Wherein the foaming agent comprises methyl formate.
The method according to claim 1,
Wherein the polyol component (A) comprises a Mannich base polyol.
3. The method of claim 2,
Wherein the Mannich-type polyol is a phenol-based polyol having a hydroxyl value of 300 to 400. 2. The composition for forming a rigid polyurethane foam according to claim 1,
3. The method of claim 2,
Wherein the content of the Mannich base polyol is 10% by weight to 30% by weight relative to 100% by weight of the polyol component (A).
The method according to claim 1,
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 150 to 400 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 1.5 to 4.0.
The method according to claim 1,
Wherein the content of the foaming agent is 5 to 20 parts by weight based on 100 parts by weight of the polyol component (A).
The method according to claim 1,
Wherein the polyol component (A) further comprises 0.5 to 3 parts by weight of water as a foaming auxiliary agent relative to 100 parts by weight of the polyol component (A).
The method according to claim 1,
Wherein the composition further comprises a reaction catalyst in a range of 0.5 to 5 parts by weight based on 100 parts by weight of the polyol component (A).
A rigid polyurethane foam formed using the composition according to any one of claims 1 to 11.
A heat insulating material comprising the rigid polyurethane foam according to claim 12.