KR102154519B1 - The polyol premix composition for rigid polyurethane foam - Google Patents

Abstract

An embodiment of the present invention provides a polyol premix composition for a rigid polyurethane foam. In one embodiment, 100 parts by weight of polyol; And 3 parts by weight to 15 parts by weight of a blowing agent; wherein the polyol includes 50 parts by weight to 80 parts by weight of a polyether polyol and 20 parts by weight to 50 parts by weight of a polyester polyol, and the blowing agent includes a hydrohaloolefin do.

Description

Polyol premix composition for rigid polyurethane foam {THE POLYOL PREMIX COMPOSITION FOR RIGID POLYURETHANE FOAM}

The present invention relates to a polyol premix composition for a rigid polyurethane foam, and more particularly, to a polyol premix composition for a rigid polyurethane foam containing hydrohaloolefin and improved thermal conductivity.

Rigid polyurethane foam is widely used in shipyards and construction sites due to its excellent mechanical strength, dimensional stability, and insulation performance, and is known as a material for insulation of tanks such as building panels, refrigerated warehouse panels, and LNG, LEG, and LPG.

Conventional rigid polyurethane foams are prepared in a mixture of polyether polyol, polyester polyol, foam stabilizer, catalyst, foaming agent, etc., and additionally mixed with an isocyanate-based compound to form a continuous conveyor belt using a low-pressure and high-pressure foaming machine. Slab stock foam was prepared by spraying. At this time, when manufacturing a conventional rigid polyurethane foam, HCFC (hydrochlorofluorocarbon) series, HFC (hydrofluorocarbon) series and CO ₂ were used as blowing agents.

On the other hand, the hydrochlorofluorocarbon-based foaming agent is a material that destroys the ozone layer in the atmosphere and increases the global warming index, and hydrofluorocarbon does not destroy the ozone layer, but its use is not preferable as a material corresponding to the global warming index. Its use is banned in many countries. The CO ₂ foaming agent is a chemical foaming agent through water and is eco-friendly for ozone and global warming, but has a disadvantage in that the thermal conductivity of the foam is low compared to the physical foaming agent introduced above. Accordingly, hydrohaloolefins, for example, hydrochlorofluoroolefins, have been developed as blowing agents for rigid polyurethane foams.

However, it is known that when a hydrochlorofluoroolefin-based foaming agent is used, the thermal conductivity of the prepared rigid polyurethane foam is poorer than that of a hydrofluorocarbon-based foaming agent.

Therefore, it is urgent to develop a composition of a polyol premix composition capable of improving the thermal insulation properties of the manufactured rigid polyurethane foam while using a hydrohaloolefin-based foaming agent.

The present invention improves the storage stability of the polyol premix composition and improves the thermal insulation properties of the manufactured rigid polyurethane foam even when the hydrohaloolefin-based foaming agent is used as described above, compared to the case of using a conventional hydrofluorocarbon-based foaming agent. It is intended to provide a polyol premix composition for a rigid polyurethane foam that can be made.

In order to solve the above problems, the present invention comprises 100 parts by weight of polyol; And 3 parts by weight to 15 parts by weight of a blowing agent; wherein the polyol includes 50 parts by weight to 80 parts by weight of a polyether polyol and 20 parts by weight to 50 parts by weight of a polyester polyol, and the blowing agent includes a hydrohaloolefin It provides a polyol premix composition for a rigid polyurethane foam.

The present invention also provides a rigid polyurethane foam prepared by reacting 80 parts by weight to 150 parts by weight of an isocyanate compound with the polyol premix composition in order to solve the above problems.

Although the polyol premix composition for a rigid polyurethane foam according to the present invention uses a hydrohaloolefin-based foaming agent as a foaming agent, storage stability and thermal insulation properties are improved compared to the case of using a hydrofluorocarbon-based foaming agent.

The present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. It is provided to inform you.

The polyol premix composition for a rigid polyurethane foam according to the present invention includes a polyol, a foaming agent, and an isocyanate compound. The inventors of the present invention repeated related experiments to invent a composition in which thermal conductivity is improved compared to the case of using a conventional hydrofluorocarbon-based foaming agent even though a hydrohaloolefin-based foaming agent is used, and as a result, an average within a specific range It was confirmed that there are surprising effects when controlling the composition of the polyether polyol and the polyester polyol having a hydroxyl value.

An embodiment of the present invention comprises 100 parts by weight of a polyol and 3 parts by weight to 15 parts by weight of a foaming agent, and the polyol comprises 50 parts by weight to 80 parts by weight of a polyether polyol and 20 parts by weight to 50 parts by weight of a polyester polyol, , The foaming agent provides a polyol premix composition for a rigid polyurethane foam comprising a hydrohaloolefin.

The polyether polyol may be polymerized by adding propylene oxide (PO) and ethylene oxide (EO) to an initiator containing a compound having 2 to 8 hydroxy groups per molecule.

For example, the initiator is sorbitol, sucrose, glycerin (glycerine), pentaerythritol (pentaerythritol), trimethylol (trimethylol), ethylene glycol (ethylene glycol) and propylene glycol (propylene glycol) Any one or more selected from the group consisting of may be included, and the number average molecular weight may be 100 g/mol to 2000 g/mol.

The polyether polyol may be prepared by combining a plurality of prepolyols. For example, the prepolyol has an average hydroxyl group of 350 to 550 mgKOH/g, 15 to 35 parts by weight of sorbitol and glycerin-based prepolyol 1, an average hydroxyl group of 400 to 600 mgKOH/g, and 15 to 35 parts by weight of sorbitol And glycerin-based prepolyol 2, an average hydroxyl group of 320 to 520 mgKOH/g, and 20 to 40 parts by weight of sucrose and glycerin-based prepolyol 3, and an average hydroxyl group of 430 to 630 mgKOH/g and 20 to 40 parts by weight It may contain any one or more selected from negative sucrose and glycerin-based prepolyol 4. In this case, the parts by weight are based on 100 parts by weight of polyol.

In addition, if necessary, a crosslinking agent may be further included, and for example, 0.5 to 10 parts by weight may be included, and for example, 1,4-Butanediol (1,4 BD) may be included.

On the other hand, the glycerin used to prepare the polyether polyol may be included in 3 parts by weight to 15 parts by weight based on 100 parts by weight of the polyol.

The polyester polyol may have an average hydroxyl value of 200 mgKOH/g to 430 mgKOH/g.

For example, the polyester polyol is selected from the group consisting of phthalic anhydride, terephthalic acid, adipic acid, ethylene glycol, and diethylene glycol. It may include a compound synthesized by polymerizing one or more of the raw materials.

Specifically, the polyester polyol reacts with phthalic anhydride, terephthalic acid, and/or adipic acid with ethylene glycol, and/or diethylene glycol. It may be one type of polyol or a mixture of two types of polyols obtained by making them.

The isocyanate compounds are aromatic isocyanates, aliphatic isocyanates, alicyclic isocyanates, and modified products thereof (e.g. carbodiimide-, allophanate-, urea-, biuret-, isocyanurate-, and oxazolidone- Modified products), isocyanate group-terminated prepolymers, and the like.

For example, the isocyanate compounds include toluene diisocyanate (TDI), diphenylmethane diisocyanate (monomer MDI), polymethylene polyphenyl isocyanate (polymer MDI), and combinations thereof.

The isocyanate compound may contain 80 parts by weight to 150 parts by weight per 100 parts by weight of the polyol, and for example, 90 parts by weight to 130 parts by weight. When an isocyanate compound within the above numerical range is used, compatibility with the polyol may be improved.

The isocyanate index (NCO/OH ratio) may be 50 to 150, and for example, 100 to 140. When reacting a compound having an isocyanate index in the above range with a polyol according to an embodiment of the present invention, the prepared rigid polyurethane foam has excellent reactivity, free foam density, thermal conductivity, compressive strength, and flame retardancy This can be improved.

The foaming agent serves to form a foaming cell inside the insulating material by generating gas in the polymerization reaction process.Since it is present in the cell after forming the polyurethane foam, it is preferable to use a material with low thermal conductivity and high stability. It is possible to use a low-olefin-based blowing agent.

The hydrohaloolefin blowing agent may include, for example, a hydrofluoroolefin (HFO) blowing agent, and may include, for example, a C ₃ ~C ₆ compound.

For example, the hydrofluoroolefin (HFO) blowing agent may include pentafluoropropane, such as 1,2,3,3,3-pentafluoropropene (HFO1225ye); Tetrafluoropropenes such as 1,3,3,3-tetrafluoropropene (HFO1234ze, E and Z isomers), 2,3,3,3-tetrafluoropropene (HFO1234yf), and 1,2, 3,3-tetrafluoropropene (HFO1234ye); Trifluoropropene such as 3,3,3-trifluoropropene (1243zf); Tetrafluorobutene such as (HFO1345); Pentafluorobutene isomers such as (HFO1354); Hexafluorobutene isomers such as (HFO1336); Heptafluorobutene isomers such as (HFO1327); Heptafluoropentene isomers such as (HFO1447); Octafluoropentene isomers such as (HFO1438); And nonafluoropentene isomers such as (HFO1429).

The hydrohaloolefin blowing agent may include, for example, a hydrochlorofluoroolefin (HCFO) blowing agent.

For example, the hydrochlorofluoroolefin (HCFO) blowing agent is 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), 2-chloro-3,3,3-trifluoropropene Pen (HCFO-1233xf), HCFO-1223, 1,2-dichloro-1,2-difluoroethene (E and Z isomers), 3,3-dichloro-3-fluoropropene, 2-chloro- 1,1,1,4,4,4-hexafluorobutene-2 (E and Z isomers), 2-chloro-1,1,1,3,4,4,4-heptafluorobutene-2 ( E and Z isomers), and the like.

The foaming agent may be included in an amount of 20 parts by weight or less, for example, 15 parts by weight or less, for example, 10 parts by weight or less per 100 parts by weight of the polyol. By using the foaming agent in the above numerical range in the present invention, the density of the rigid polyurethane foam can be controlled. The density of the rigid polyurethane foam of the present invention can be adjusted to 40 ~ 210kg / m ^3, for example, it is adjusted to 80 ~ 140 kg / m ^3. Within the above numerical range, the rigid polyurethane foam according to the present invention can be optimized for the use of interior materials such as LNG ships/land LNG tanks/Fuel Tanks.

Meanwhile, in addition to the hydrohaloolefin-based (hydrofluoroolefin (HFO), hydrochlorofluoroolefin (HCFO)) blowing agent, the blowing agent may be added with an additional blowing agent such as water or a volatile blowing agent. Volatile blowing agents used may be known volatile blowing agents other than hydrohaloolefins, examples of which include low boiling point hydrocarbons (e.g., pentane, cyclopentane, hexane, and mixtures thereof), carbon dioxide gas, or mixtures thereof. can do.

On the other hand, the rigid polyurethane foam according to the present invention can improve the storage stability of the stock solution. While the boiling point of the conventionally used hydrofluorocarbon-based blowing agent, for example, HFC-245fa, is 15.4° C., the boiling point of the hydrohaloolefin-based blowing agent according to the present invention, for example, HFO-1233zd, is 19 At ℃, as the stability of the low-temperature stock solution storage of the rigid polyurethane foam according to the present invention increases, the prepared rigid polyurethane foam has excellent reactivity, and free foam density, thermal conductivity, compressive strength, and flame retardancy can be improved.

The polyol premix composition may further include a foaming agent, and the foaming agent may be included in an amount of 0.5 to 10 parts by weight per 100 parts by weight of the polyol.

The foaming agent is capable of preventing the cells from being combined with each other or destroying the resulting cells when cells are formed in the foam, and improving the mixing properties between different compositions, stability and uniformity of the cells, and includes a silicone-based foaming agent. can do.

At this time, the foaming agent may be used in the form of a mixture of a silicone foaming agent and a non-silicone foaming agent, and thus, not only can suppress the occurrence of pinholes in the foam, but also make the surface of the manufactured foam flat. Thus, the quality of the manufactured foam can be improved.

The polyol premix composition may further include a flame retardant as needed, and for example, may include 5 parts by weight to 30 parts by weight per 100 parts by weight of the polyol. If the flame retardant is included in less than 5 parts by weight, the effect on the improvement of flame retardancy may be insignificant, and if it is included in more than 30 parts by weight, the degree of reaction between the polyol and the isocyanate compound decreases as the relative composition ratio of the polyol decreases. Can cause problems.

The flame retardant may include any one or more selected from the group consisting of a phosphorus-based flame retardant, a nitrogen-based flame retardant, an inorganic flame retardant, and a halogen-based flame retardant, while realizing the flame retardancy of the foam and at the same time, the polyurethane bonding reaction between the polyol and the isocyanate compound It is preferable to use one that can suppress side reactions that may occur.

The polyol premix composition may further include a catalyst as necessary, and the catalyst may be included in an amount of 10 parts by weight or less per 100 parts by weight of the polyol. When the content of the catalyst exceeds 10 parts by weight, the reaction rate is no longer improved, so that the effectiveness of the catalyst may decrease.

The catalyst is a configuration capable of accelerating or delaying the reaction rate between the polyol and the isocyanate compound without directly participating in the polymerization reaction, and the kind is not particularly limited, for example, an amine-based catalyst, a potassium catalyst, or a Tin-based catalyst. Catalysts can be used.

For example, the amine-based catalyst is dimethylethanol amine (DMEA), dimethylcyclohexyl amine (DMCHA), pentamethylenediethylene triamine (PMDETA), and tetramethylene-hexyldiamine ( Any one or more selected from the group consisting of tertamethylene-hexyldiamine, TMHDA) may be used, and a Tin-based catalyst may be used to induce a faster reaction rate than an amine-based catalyst or a potassium catalyst.

Meanwhile, a method of manufacturing a polyurethane foam using the polyol premix composition for a rigid polyurethane foam according to the present invention may follow a known method.

For example, the method described in Saunders and Frisch, Volumes I and II Polyurethanes Chemistry and technology, 1962, John Wiley and Sons, New York, N.Y. can be followed.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is presented as a preferred example of the present invention and cannot be construed as limiting the present invention in any sense.

Contents not described herein can be sufficiently technically inferred by those skilled in the art, and thus description thereof will be omitted.

Example

Preparation Example 1-Preparation of prepolyol

As a step before preparing the polyether polyol, a plurality of prepolyols were prepared. As an initiator, sorbitol, sucrose, and glycerine were used as follows. A polyether polyol was prepared by adding propylene oxide and ethylene oxide to the initiator, and using 3 parts by weight of 1,4-Butanediol (1,4 BD) as a crosslinking agent. At this time, the 1,4-Butanediol hydroxyl group was set to be 1000 mgKOH/g to 1500 mgKOH/g, and the glycerine hydroxyl group was set to 1600 mgKOH/g to 2000 mgKOH/g.

-Prepolyol 1: Addition of propylene oxide and ethylene oxide to 25 parts by weight of sorbitol with an average hydroxyl group of 430 to 470 mgKOH/g and glycerin mixture

-Prepolyol 2-1: Addition of propylene oxide and ethylene oxide to 25 parts by weight of sorbitol with an average hydroxyl group of 455 to 485 mgKOH/g and glycerin mixture

-Prepolyol 2-2: Addition of propylene oxide and ethylene oxide to 15 parts by weight of sorbitol with an average hydroxyl group of 455 to 485 mgKOH/g and glycerin mixture

-Prepolyol 2-3: Addition of propylene oxide and ethylene oxide to 35 parts by weight of sorbitol with an average hydroxyl group of 455 to 485 mgKOH/g and glycerin mixture

-Prepolyol 2-4: Addition of propylene oxide and ethylene oxide to 10 parts by weight of sorbitol with an average hydroxyl group of 455 to 485 mgKOH/g and glycerin mixture

-Prepolyol 2-5: Addition of propylene oxide and ethylene oxide to 40 parts by weight of sorbitol with an average hydroxyl group of 455 to 485 mgKOH/g and glycerin mixture

-Prepolyol 3: Addition of propylene oxide and ethylene oxide to 30 parts by weight of sucrose with an average hydroxyl group of 405 to 435 mgKOH/g and glycerin mixture

-Prepolyol 4-1: 30 parts by weight of sucrose with an average hydroxyl group of 495 to 515 mgKOH/g and propylene oxide and ethylene oxide added to the glycerin mixture

-Prepolyol 4-2: Addition of propylene oxide and ethylene oxide to 40 parts by weight of sucrose having an average hydroxyl group of 495 to 515 mgKOH/g and glycerin mixture

-Prepolyol 4-3: Addition of propylene oxide and ethylene oxide to 20 parts by weight of sucrose having an average hydroxyl group of 495 to 515 mgKOH/g and glycerin mixture

-Prepolyol 4-4: Addition of propylene oxide and ethylene oxide to 10 parts by weight of sucrose having an average hydroxyl group of 495 to 515 mgKOH/g and glycerin mixture

Preparation Example 2-Preparation of polyether polyol

Polyether polyols were prepared by mixing a plurality of prepolyols. At this time, when preparing the polyether polyol, 7 parts by weight of glycerin were included.

-Polyether polyol 1: mixing of prepolyol 1 and prepolyol 3

-Polyether polyol 2: mixing of prepolyol 1 and prepolyol 4-1

-Polyether polyol 3: Mixing of prepolyol 2-1 and prepolyol 3

-Polyether polyol 4: Mixing of prepolyol 2-1 and prepolyol 4-1

-Polyether polyol 5: mixing of prepolyol 2-2 and prepolyol 4-2

-Polyether polyol 6: mixing of prepolyol 2-3 and prepolyol 4-3

-Polyether polyol 7: Mixing of prepolyol 2-4 and prepolyol 4-2

-Polyether polyol 8: mixing of prepolyol 2-5 and prepolyol 4-4

Example-Preparation of polyol premix composition

As a polyol component, a mixture of polyether polyol and polyester polyol was used. A foaming agent, a flame retardant, a foaming agent, and a catalyst were mixed with the polyol component, and an isocyanate compound was stirred thereto to perform a foaming process.

To form a rigid polyurethane foam, a stirrer, low pressure or high pressure foaming machine was used, and the storage temperature and hose temperature of the mixture of the polyol and isocyanate compound were controlled to 20 to 30 °C, and the operating pressure was controlled to 300 to 3000 psi. The demoulding time of the urethane foam was set to 30 minutes.

Each composition of the polyurethane spray foam compositions prepared according to Examples 1 to 12 and Comparative Examples 1 to 3 is as shown in Tables 3 to 4 below.

division Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Polyetherpolyol 1
(Part by weight) 65 65 Polyether polyol 2
(Part by weight) 65 65 Polyetherpolyol 3
(Part by weight) 65 65 Polyetherpolyol 4
(Part by weight) 65 65 Polyester polyol 1 (parts by weight) 35 35 35 35 Polyester polyol 2 (parts by weight) 35 35 35 35 B-8462 (parts by weight) 2 2 2 2 2 2 2 2 Catalyst 1 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Catalyst 2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 HFC-245fa HFO-1233zd 8 8 8 8 8 8 8 8 MDI (parts by weight) 108 106 117 114 112 109 120 117

division Example 9 Example 10 Example 11 Example 12 Comparative Example 1 Comparative Example 2 Comparative Example 3 Polyetherpolyol 1
(Part by weight) 65 Polyetherpolyol 4
(Part by weight) 65 65 Polyetherpolyol 5
(Part by weight) 65 Polyetherpolyol 6
(Part by weight) 65 Polyether polyol 7
(Part by weight) 65 Polyether polyol 8
(Part by weight) 65 Polyester polyol 1 (parts by weight) 35 35 35 35 35 35 Polyester polyol 2 (parts by weight) 35 B-8462 (parts by weight) 2 2 2 2 2 2 2 Catalyst 1 0.3 0.3 0.3 0.3 0.2 0.2 0.2 Catalyst 2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 HFC-245fa 8.25 8.25 8.25 HFO-1233zd 8.5 8.5 8.3 8.3 P-MDI (parts by weight) 120 117 121 119 108 120 118

Average hydroxyl group (OHv, mgKOH/g) Polyester Polyol 1 320~340 Polyester polyol 2 285~315

Experimental example

The free foam density and thermal conductivity of the polyurethane foams prepared according to Examples 1 to 12 and Comparative Examples 1 to 3 were evaluated, and the results are shown in Tables 6 to 7 below.

division Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Free foam density
(kg/m ³ ) 118 116 124 122 119 117 125 123 Thermal conductivity (20℃) (W/mk) 0.025 0.0248 0.0245 0.0242 0.0247 0.0244 0.024 0.0238

division Example 9 Example 10 Example 11 Example 12 Comparative Example 1 Comparative Example 2 Comparative Example 3 Free foam density
(kg/m ³ ) 119 119 120 117 119 116 118 Thermal conductivity (20℃) (W/mk) 0.02265 0.02284 0.02268 0.02270 0.026 0.02620 0.02650

(1) Measurement of free foam density

The density of the foam prepared by foaming the polyol premix composition was measured while minimizing interference from the outside. In other words, the density was calculated by measuring the volume and weight by cutting the foam produced in a cup, box, plastic bag, etc. without a lid into a certain size without over packing. The density was measured by the weight per unit volume of the polyurethane spray foam produced. Specifically, it was measured according to ISO 845 regulations.

(2) Measurement of thermal conductivity

Heat conduction was measured according to KS M-3809, and the result was converted into adiabatic value (W/mK) and recorded.

As shown in the above experimental examples, even though the rigid polyurethane foam according to an embodiment of the present invention uses a hydrohaloolefin series as a foaming agent, the thermal conductivity is more surprising than when using a hydrofluorocarbon (HFC) series. I could confirm.

That is, the polyol premix composition for a rigid polyurethane foam using a hydrohaloolefin-based blowing agent includes 3 parts by weight to 15 parts by weight of a hydroolefin-based blowing agent and 80 parts by weight to 150 parts by weight of an isocyanate compound per 100 parts by weight of polyol. And, the polyol includes 50 parts by weight to 80 parts by weight of polyether polyol and 20 parts by weight to 50 parts by weight of polyester polyol, and the polyether polyol includes two or more prepolyols, based on 100 parts by weight of polyol, with an average hydroxyl group of 350 ~550 mgKOH/g, 15 to 35 parts by weight of sorbitol and glycerin-based prepolyol 1, an average hydroxyl group of 400 to 600 mgKOH/g, and 15 to 35 parts by weight of sorbitol and glycerin-based prepolyol 2, an average hydroxyl group of 320 ~520 mgKOH/g and 20 to 40 parts by weight of sucrose and glycerin-based prepolyol 3, and an average hydroxyl group of 430 to 630 mgKOH/g and 20 to 40 parts by weight of sucrose and glycerin-based prepolyol 4 When including any one or more selected, it was confirmed that the compatibility between the polyol premix composition and the hydrohaloolefin-based foaming agent was excellent, and thus thermal conductivity could be improved.

As described above, a detailed description of the present invention has been made by an embodiment with reference to the accompanying drawings, but the above-described embodiment has been described with reference to a preferred example of the present invention, so that the present invention is limited to the above embodiment. It should not be understood, and the scope of the present invention should be understood as the following claims and equivalent concepts.

Claims (7)

100 parts by weight of polyol; And
3 to 15 parts by weight of a blowing agent;
Including,
The polyol includes 50 parts by weight to 80 parts by weight of polyether polyol and 20 parts by weight to 50 parts by weight of polyester polyol,
The blowing agent includes a hydrohaloolefin,
The polyether polyol is (a) a first prepolyol based on sorbitol and glycerin; And (b) at least one selected from the group consisting of sucrose, glycerin, pentaerythritol, trimethylol, ethylene glycol, and propylene glycol. A polyol premix composition for a rigid polyurethane foam comprising a second prepolyol polymerized from an initiator.
delete delete The method according to claim 1,
The polyether polyol is (a) an average hydroxyl group of 350 to 550 mgKOH/g, 15 to 35 parts by weight of sorbitol and glycerin-based prepolyol 1, and an average hydroxyl group of 400 to 600 mgKOH/g, and 15 to 35 parts by weight Any one or more first prepolyols selected from the group consisting of negative sorbitol and glycerin-based prepolyol 2; And (b) an average hydroxyl group of 320 to 520 mgKOH/g, 20 to 40 parts by weight of sucrose and glycerin-based prepolyol 3, and an average hydroxyl group of 430 to 630 mgKOH/g, and 20 to 40 parts by weight of sucrose and A polyol premix composition comprising at least one second prepolyol selected from the group consisting of glycerin-based prepolyol 4.
The method according to claim 1,
The polyester polyol has an average hydroxyl value of 200 mgKOH/g to 430 mgKOH/g, a polyol premix composition.
The method of claim 5,
The foaming agent is contained in an amount of 3 to 10 parts by weight per 100 parts by weight of polyol, a polyol premix composition.
A rigid polyurethane foam prepared by reacting 80 parts by weight to 150 parts by weight of an isocyanate compound with the polyol premix composition according to any one of claims 1 and 4 to 6.