KR20240171414A - Polyol composition for producing rigid polyurethane foam - Google Patents

Abstract

The polyol composition for producing a rigid polyurethane foam of the present invention comprises an isophthalic acid-based polyester polyol; lignin; and a phosphorus-based flame retardant; and is characterized in that the particle size of the dispersed phase measured with an optical microscope after 7 days from production is 30 ㎛ or less. The polyol composition for producing a rigid polyurethane foam has excellent dispersion stability, etc., and can produce a rigid polyurethane foam having excellent semi-fire resistance, insulation properties, etc.

Description

Polyol composition for producing rigid polyurethane foam {POLYOL COMPOSITION FOR PRODUCING RIGID POLYURETHANE FOAM}

The present invention relates to a polyol composition for producing rigid polyurethane foam. More specifically, the present invention relates to a polyol composition for producing rigid polyurethane foam capable of producing rigid polyurethane foam having excellent dispersion stability, etc., and excellent semi-flammability, thermal insulation, etc.

Rigid polyurethane foam is one of the most popular insulation materials in terms of industrial and thermal insulation. However, insulation is the most vulnerable to fire and heat among construction materials, so there are growing voices calling for strengthening the semi-combustibility (flame retardancy and reduction of harmful gases) standards for insulation to prevent the spread of fire in the event of a fire.

In order to meet the strengthened semi-combustibility evaluation criteria for insulation materials, the heat release of the core material itself, excluding the face material (such as Al-GF film) surrounding the core material (such as rigid polyurethane foam), must meet the semi-combustibility evaluation criteria. However, existing rigid polyurethane foams cannot achieve the heat release, etc. that satisfies the semi-combustibility evaluation criteria.

Therefore, there is a need to develop a polyol composition for manufacturing rigid polyurethane foam with excellent flame retardancy (flame retardancy and reduction of harmful gases) and insulation properties.

The background technology of the present invention is disclosed in Korean Patent Publication No. 10-2009-0095889, etc.

The purpose of the present invention is to provide a polyol composition for producing rigid polyurethane foam, which can produce rigid polyurethane foam having excellent dispersion stability, semi-non-flammability, and excellent insulation properties.

The above and other objects of the present invention can all be achieved by the present invention described below.

1. One aspect of the present invention relates to a polyol composition for producing a rigid polyurethane foam. The polyol composition for producing a rigid polyurethane foam comprises an isophthalic acid-based polyester polyol; lignin; and a phosphorus-based flame retardant; and is characterized in that, after 7 days from production, the particle size of the dispersed phase measured with an optical microscope is 30 ㎛ or less.

2. In the above 1 specific example, the isophthalic acid-based polyester polyol can be represented by the following chemical formula 1:

[Chemical Formula 1]

In the above chemical formula 1, L ₁ is a hydroxy group and A straight or branched chain alkylene group having 1 to 6 carbon atoms, substituted or unsubstituted by at least one of; or a hydroxyl group and A straight or branched chain ether group having 2 to 6 carbon atoms which is unsubstituted or substituted with at least one of; and L ₂ is a straight or branched chain alkylene group having 1 to 5 carbon atoms which is unsubstituted or substituted with a hydroxy group; or a straight or branched chain ether group having 1 to 5 carbon atoms which is unsubstituted or substituted with a hydroxy group; and m is an integer from 1 to 50 and n is an integer from 1 to 21.

3. In the above specific examples 1 or 2, the isophthalic acid-based polyester polyol may have a hydroxyl value (OH value) of 10 to 500 mgKOH/g.

4. In the above specific examples 1 to 3, the isophthalic acid-based polyester polyol may have a weight average molecular weight of 200 to 10,000 g/mol.

5. In the above 1 to 4 specific examples, the phosphorus flame retardant may include at least one of a liquid phosphorus flame retardant including at least one of triethyl phosphate, diethyl ethyl phosphonate, dimethyl methyl phosphonate, dimethyl propyl phosphonate, diphenyl cresyl phosphate, and tricresyl phosphate; and a halogenated phosphorus flame retardant including at least one of tris (1-chloro-2-propyl) phosphate, tris (2-chloroethyl) phosphate, tris (1,3-dichloropropyl) phosphate, tris (2,3-dibromopropyl) phosphate, and tetrakis (2-chloroethyl) ethylene diphosphate.

6. In the above 1 to 5 specific examples, the phosphorus flame retardant may include a liquid phosphorus flame retardant.

7. In the above 1 to 6 specific examples, the phosphorus flame retardant may include a liquid phosphorus flame retardant and a halogenated phosphorus flame retardant.

8. In the above 1 to 6 specific examples, the polyol composition for producing the rigid polyurethane foam may include 100 parts by weight of the isophthalic acid-based polyester polyol; 0.5 to 7 parts by weight of the lignin; and 15 to 40 parts by weight of the phosphorus flame retardant.

9. In the above specific examples 1 to 8, the polyol composition for producing the rigid polyurethane foam may further include 5 to 40 parts by weight of a blowing agent per 100 parts by weight of the isophthalic acid-based polyester polyol.

10. In the above specific examples 1 to 9, the rigid polyurethane foam manufactured by mixing and reacting the polyol composition for manufacturing the rigid polyurethane foam and diphenylmethane diisocyanate may have a particle size of a dispersed phase of 30 ㎛ or less in a 10 cm × 10 cm × 1 cm sized specimen measured using an optical microscope.

11. In the above 1 to 10 specific examples, the weight ratio of the isophthalic acid-based polyester polyol and the diphenylmethane diisocyanate may be 1:1.5 to 1:3.

12. In the above specific examples 1 to 11, the rigid polyurethane foam may have a polyisocyanurate ratio (PIR ratio) of 4.5 to 7 according to the following formula 1, and a residual diphenylmethane diisocyanate ratio (MDI ratio) of 0.1 to 0.5 according to the following formula 2:

[Formula 1]

Polyisocyanurate ratio (PIR ratio) = PIR / (PUR + Urea + PIR + MDI)

[Formula 2]

Residual diphenylmethane diisocyanate ratio (MDI ratio) = MDI / (PUR + Urea + PIR + MDI)

In the above equations 1 and 2, PUR + Urea + PIR + MDI are FT-IR absorbance values of a phenyl group (range of 1,565 to 1,625 cm ^-1 ) commonly included in polyurethane, urea, polyisocyanurate, and diphenylmethane diisocyanate, PIR is an FT-IR absorbance value of a polyisocyanurate structure including an isocyanurate group (range of 1,340 to 1,465 cm ^-1 ), and MDI is an FT-IR absorbance value of an isocyanate group (range of 2,200 to 2,317 cm ^-1 ).

13. In the above specific examples 1 to 12, the rigid polyurethane foam may have a heat release rate of 3 to 8 MJ/m ² as measured by a cone calorimeter according to KS F ISO 5660-1.

14. In the above specific examples 1 to 13, the rigid polyurethane foam may have an average behavioral cessation time of 9 to 12 minutes in a closed space injected with combustion gas of the rigid polyurethane foam specimen as measured according to KS F 2271.

15. In the above specific examples 1 to 14, the rigid polyurethane foam may have a thermal conductivity of 0.017 to 0.024 W/m·K as measured according to KS M 3809.

The present invention has the effect of providing a polyol composition for producing rigid polyurethane foam having excellent flame retardancy, thermal insulation, etc.

Hereinafter, the present invention will be described in detail as follows.

A polyol composition for producing a rigid polyurethane foam according to the present invention comprises (A) an isophthalic acid-based polyester polyol; (B) lignin; and (C) a phosphorus-based flame retardant.

In this specification, “a to b” indicating a numerical range is defined as “≥a and ≤b”.

(A) Isophthalic acid polyester polyol

According to one specific example of the present invention, an isophthalic acid-based polyester polyol has excellent reactivity with diphenylmethane isocyanate and can improve the semi-non-flammability, thermal insulation, compressive strength, etc. of rigid polyurethane foam. An isophthalic acid-based polyester polyol represented by the following chemical formula 1 can be used.

[Chemical Formula 1]

In the above chemical formula 1, L ₁ is a hydroxy group and A straight or branched chain alkylene group having 1 to 6 carbon atoms, substituted or unsubstituted by at least one of; or a hydroxyl group and A straight or branched chain ether group having 2 to 6 carbon atoms which is unsubstituted or substituted with at least one of; and L ₂ is a straight or branched chain alkylene group having 1 to 5 carbon atoms which is unsubstituted or substituted with a hydroxy group; or a straight or branched chain ether group having 1 to 5 carbon atoms which is unsubstituted or substituted with a hydroxy group; and m is an integer from 1 to 50 and n is an integer from 1 to 21.

In embodiments, L ₁ is -CH ₂ -CH ₂ -; -CH ₂ -C(CH ₃ ) ₂ -CH ₂ -; -CH ₂ -C(CH ₂ CH ₃ )(CH ₂ OH)-CH ₂ -; -CH ₂ -CH(CH ₃ )-CH ₂ -; -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -; -CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -; ; ; ; ; ; or , and n is an integer from 3 to 21.

In specific examples, L ₂ is -CH ₂ -; -C(CH ₃ ) ₂ -CH ₂ -; -C(CH ₂ CH ₃ )(CH ₂ OH)-CH ₂ -; -CH(CH ₃ )-CH ₂ -; -CH ₂ -OCH ₂ -CH ₂ -; or -CH ₂ -O-CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -.

In specific examples, L ₁ can be -CH ₂ -CH ₂ -, and L ₂ can be -CH ₂ -.

In a specific example, the isophthalic acid-based polyester polyol can be produced by reacting isophthalic acid and an alcohol represented by the following chemical formula 2 to produce a polyol represented by the following chemical formula 3, and by reacting the polyol represented by the following chemical formula 3 with a compound represented by the following chemical formula 4.

[Chemical formula 2]

[Chemical Formula 3]

[Chemical Formula 4]

In the above chemical formulas 2 to 4, L ₃ is a straight-chain or branched-chain alkylene group having 2 to 6 carbon atoms, which is unsubstituted or substituted with a hydroxy group; or a straight-chain or branched-chain ether group having 2 to 6 carbon atoms, which is unsubstituted or substituted with a hydroxy group, m is an integer from 1 to 50, and n is an integer from 3 to 21.

In a specific example, the compound represented by the chemical formula 2 may be added in a ratio of 1.1 to 2.5 mol per 1 mol of the isophthalic acid, and the reaction of the isophthalic acid and the alcohol represented by the chemical formula 2 may be performed under normal pressure and 140 to 240°C.

In a specific example, the compound represented by the chemical formula 4 may be added in a ratio of 0.01 mol to 0.1 mol with respect to 1 mol of the polyol represented by the chemical formula 3, and the reaction of the compound represented by the chemical formula 4 and the polyol represented by the chemical formula 3 may be performed in the presence of an acid-base catalyst under normal pressure and conditions of 100 to 220°C.

In a specific example, the isophthalic acid-based polyester polyol may have a hydroxyl value (OH value) of 10 to 500 mgKOH/g as measured according to JIS K1557-1:2007. Within this range, a required rigid polyurethane foam can be formed.

In a specific example, the isophthalic acid-based polyester polyol may have a weight average molecular weight of 200 to 10,000 g/mol as measured by gel permeation chromatography (GPC).

(B) Lignin

According to one specific example of the present invention, lignin can be applied as a polyol composition with an isophthalic acid-based polyester polyol, a phosphorus-based flame retardant, etc., to improve the semi-non-combustibility, insulating properties, etc. of rigid urethane foam, and can be applied in a solution state together with the phosphorus-based flame retardant.

In a specific example, the lignin may be in the form of granules, powder, etc. When the lignin is in the form of granules, the particle size may be about 3 mm or less, and when the lignin is in the form of powder, the particle size may be about 200 ㎛ or less. When the lignin is completely dissolved in a solution state with triethyl phosphate, the particle size in the solution phase may be less than about 1 ㎛. In the above range, the semi-flammability, rigidity, etc. of the rigid polyurethane foam may be excellent.

In a specific example, for the rigid polyurethane foam, whether lignin is included can be confirmed through Pyrolyzer-Gas chromatography/Mass spectrometry (Py-GC/MS) analysis. In the chemical analysis results, the presence or absence of peaks of methoxy phenol, methoxy cresol, and methoxy vinylphenol, which are some of the lignin-containing substances, can be confirmed, and through this, whether lignin is applied to the rigid polyurethane foam can be confirmed.

In a specific example, the lignin may be included in an amount of 0.5 to 7 parts by weight, for example, 1 to 3 parts by weight, based on 100 parts by weight of the isophthalic acid-based polyester polyol. In this range, the semi-flammability, rigidity, etc. of the rigid urethane foam may be excellent.

(C) Inherited flame retardant

According to one specific example of the present invention, a phosphorus-based flame retardant is applied as a polyol composition with isophthalic acid-based polyester polyol and lignin, etc., and can improve the semi-non-combustibility, thermal insulation, etc. of rigid urethane foam. A conventional phosphorus-based flame retardant applied to urethane foam, etc. can be used, and can be applied in a solution state together with the lignin.

In specific examples, the phosphorus flame retardant may be a liquid phosphorus flame retardant such as triethyl phosphate, diethyl ethyl phosphonate, dimethyl methyl phosphonate, dimethyl propyl phosphonate, diphenyl cresyl phosphate, tricresyl phosphate, and combinations thereof; and a halogenated phosphorus flame retardant such as tris (1-chloro-2-propyl) phosphate, tris (2-chloroethyl) phosphate, tris (1,3-dichloropropyl) phosphate, tris (2,3-dibromopropyl) phosphate, tetrakis (2-chloroethyl) ethylene diphosphate, and combinations thereof; used alone or in combination of two or more. For example, a liquid phosphorus flame retardant alone or a combination of a liquid phosphorus flame retardant and a halogenated phosphorus flame retardant may be used. Specifically, triethyl phosphate (TEP) alone or a combination of triethyl phosphate (TEP) and tris(1-chloro-2-propyl) phosphate (TCPP) may be used, but is not limited thereto.

In a specific example, the lignin and the liquid phosphorus-based flame retardant may have a weight ratio of 1:2.5 to 1:15. In the above range, the lignin and the liquid phosphorus-based flame retardant may be applied to the polyol composition in a solution state.

In a specific example, when the weight ratio of the lignin and the liquid phosphorus flame retardant is 1:7, the total amount of the lignin and the triethyl phosphate may be 20 to 25 parts by weight with respect to 100 parts by weight of the polyol. In the above range, the formability, semi-flammability, etc. of the rigid urethane foam may be excellent.

In a specific example, the above-mentioned flame retardant may be included in an amount of 15 to 40 parts by weight, for example, 17 to 35 parts by weight, based on 100 parts by weight of the above-mentioned isophthalic acid-based polyester polyol. In the above range, the formability and semi-flammability of the rigid urethane foam may be excellent.

In a specific example, when the phosphorus flame retardant is a combination (mixture) of a liquid phosphorus flame retardant and a halogenated phosphorus flame retardant, the liquid phosphorus flame retardant may be included in an amount of 15 to 30 parts by weight, for example, 15 to 25 parts by weight, based on 100 parts by weight of the isophthalic acid-based polyester polyol, and the halogenated phosphorus flame retardant may be included in an amount of 2 to 8 parts by weight, for example, 4 to 6 parts by weight, based on 100 parts by weight of the isophthalic acid-based polyester polyol. In the above range, the semi-non-flammability, processability, etc. of the rigid polyurethane foam may be excellent.

(D) Foaming agent

A polyol composition for producing a rigid polyurethane foam according to one specific example of the present invention may further include a blowing agent. The blowing agent may be applied to the polyol composition together with an isophthalic acid-based polyester polyol, lignin, a phosphorus-based flame retardant, etc., so as to function as a blowing agent without hindering the insulation properties of the rigid polyurethane foam and causing problems such as moldability and processability. A conventional blowing agent used in rigid polyurethane foam may be used.

In specific examples, the blowing agent may be 1-chloro-3,3,3-trifluoropropene (LBA), cyclopentane (CP), HFC series blowing agents (HFC-141b (1,1-dichloro-1-fluoroethane), HFC-245fa (1,1,1,3,3-pentafluoropropane), HFC-365mfc (1,1,1,3,3-pentafluorobutane), etc.), combinations thereof, etc.

In a specific example, the blowing agent may be 1-chloro-3,3,3-trifluoropropene (LBA) alone, or a mixture of 1-chloro-3,3,3-trifluoropropene (LBA) and cyclopentane (CP). The mixing ratio of 1-chloro-3,3,3-trifluoropropene (LBA) and cyclopentane (CP) may be, but is not limited to, 3:1 to 10:1.

In a specific example, the content of the blowing agent may be 5 to 40 parts by weight, for example, 10 to 35 parts by weight, based on 100 parts by weight of the isophthalic acid-based polyester polyol. The amount (content) of the blowing agent may be varied in order to control the free foaming density of the rigid polyurethane foam, and within the above range, the insulation properties and foaming efficiency, etc. may be excellent.

A polyol composition according to one specific embodiment of the present invention may further include additives used in conventional polyol compositions within a range that does not impede the purpose and effect of the present invention. Examples of the additives include, but are not limited to, a foam stabilizer, a surface-active substance, a foam stabilizer, a cell regulator, a filler, a dye, a pigment, a combination thereof, and the like. When the additives are used, the content thereof may be 0.001 to 40 parts by weight, for example, 0.05 to 25 parts by weight, based on 100 parts by weight of the isophthalic acid-based polyester polyol.

A polyol composition according to one specific example of the present invention may include a continuous phase (components other than lignin) and a dispersed phase (lignin), and the particle size of the dispersed phase measured by an optical microscope after 7 days from the preparation of the polyol composition is 30 ㎛ or less (the dispersed phase may appear not to exist). If it is out of the above range, the dispersion stability of the polyol composition may deteriorate, and there is a concern that the semi-non-combustibility (flame retardancy and reduction of harmful gases), insulation, etc. of the rigid polyurethane foam prepared therefrom may deteriorate.

A polyol composition for producing a rigid polyurethane foam according to one specific example of the present invention can form a rigid polyurethane foam by reacting with diphenylmethane diisocyanate (MDI). As the diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate (P-MDI) or the like can be used.

In a specific example, the rigid polyurethane foam can be manufactured by mixing and reacting the polyol composition for manufacturing the rigid polyurethane foam and the diphenylmethane diisocyanate.

In a specific example, the weight ratio of the isophthalic acid-based polyester polyol and the diphenylmethane diisocyanate may be 1:1.5 to 1:3, for example, 1:1.7 to 1:2.3. In the above range, a rigid polyurethane foam having the following polyisocyanurate ratio (PIR ratio) and residual diphenylmethane diisocyanate ratio (MDI ratio) can be formed, with reduced gas toxicity and excellent semi-non-flammability, insulation, rigidity, etc.

In a specific example, the reaction can be performed in the presence of a catalyst including an organometallic catalyst, at a temperature condition of 30 to 70°C, for example, 40 to 50°C, and a pressure condition of 0.8 to 1.5 kgf/cm ² , for example, 0.9 to 1.2 kgf/cm ² . In the above range, a rigid polyurethane foam having the polyisocyanurate ratio (PIR ratio) and the residual diphenylmethane diisocyanate ratio (MDI ratio) can be obtained, and the semi-noncombustibility, thermal insulation, rigidity, etc. of the rigid polyurethane foam can be excellent.

In specific examples, the organometallic catalyst may be potassium-2-ethylhexanoate, tin(II)2-ethylhexanoate, a combination thereof, or the like. In addition, catalysts that can be used together with the organometallic catalyst include amine catalysts such as pentamethyldiethylenetriamine (PMDETA) and N,N-dimethylcyclohexylamine (DMCHA).

In a specific example, the rigid polyurethane foam may include a continuous phase (components other than lignin) and a dispersed phase (lignin), and the particle size of the dispersed phase in a 10 cm × 10 cm × 1 cm specimen measured by an optical microscope is 30 ㎛ or less (the dispersed phase may appear not to exist). If the above range is exceeded, there is a concern that the semi-noncombustibility (flame retardancy and reduction of harmful gases), insulation, etc. of the rigid polyurethane foam may be deteriorated.

In a specific example, the rigid urethane foam may include a polyurethane structure (urethane reaction), an isocyanurate structure (trimerization reaction), a urea structure (urea reaction), etc., by a reaction of the polyol composition for producing the rigid urethane foam and the diphenylmethane diisocyanate, and a polyisocyanurate ratio (PIR ratio) according to the following formula 1 may be 4.5 to 7, for example, 4.8 to 6.5, and a residual diphenylmethane diisocyanate ratio (MDI ratio) according to the following formula 2 may be 0.1 to 0.5, for example, 0.1 to 0.3.

[Formula 1]

Polyisocyanurate ratio (PIR ratio) = PIR / (PUR + Urea + PIR + MDI)

[Formula 2]

Residual diphenylmethane diisocyanate ratio (MDI ratio) = MDI / (PUR + Urea + PIR + MDI)

In the above equations 1 and 2, PUR + Urea + PIR + MDI are FT-IR absorbance values of a phenyl group (range of 1,565 to 1,625 cm ^-1 ) commonly included in polyurethane, urea, polyisocyanurate, and diphenylmethane diisocyanate, PIR is an FT-IR absorbance value of a polyisocyanurate structure including an isocyanurate group (range of 1,340 to 1,465 cm ^-1 ), and MDI is an FT-IR absorbance value of an isocyanate group (range of 2,200 to 2,317 cm ^-1 ).

Within the above polyisocyanurate ratio (PIR ratio) range, it can have excellent semi-flammability (flame retardancy and reduction of harmful gases), insulation, rigidity, etc.

Within the above residual diphenylmethane diisocyanate ratio (MDI ratio) range, semi-non-combustibility (flame retardancy and reduction of harmful gases), insulation, rigidity, etc. can be excellent.

In a specific example, the rigid polyurethane foam may have a density of 30 to 50 kg/m ³ , for example, 35 to 45 kg/m ^{3 ,} as measured according to JIS K7222.

In a specific example, the rigid polyurethane foam may have a heat release rate of 3 to 8 MJ/ ^m2 , for example, 4 to 7 MJ/ ^m2 , as measured by a cone calorimeter according to KS F ISO 5660-1.

In a specific example, the rigid polyurethane foam may have an average behavioral cessation time of 9 to 12 minutes, for example, 9 minutes 30 seconds to 11 minutes, of experimental mice in a closed space injected with combustion gas of the rigid polyurethane foam specimen as measured according to KS F 2271.

In a specific example, the rigid polyurethane foam may have a thermal conductivity of 0.017 to 0.024 W/m K, for example, 0.018 to 0.023 W/m K, as measured according to KS M 3809.

Hereinafter, the present invention will be described more specifically through examples; however, these examples are for the purpose of explanation only and should not be construed as limiting the present invention.

Example

Below, the specifications of each component used in the examples and comparative examples are as follows.

(A) Isophthalic acid polyester polyol

Isophthalic acid polyester polyol (Manufacturer: Lotte Chemical, Product name: FIP-2210) was used.

(B) Lignin

Lignin (Manufacturer: Stora Enso, Product Name: Lineo) was used.

(C) Inherited flame retardant

(C1) Triethyl phosphate (Manufacturer: Kempia, Product name: Triethyl phosphate) was used.

(C2) Tris(1-chloro-2-propyl)phosphate (Manufacturer: Nanochem, Product name: 1-chloro-2-propanol phosphate) was used.

(D) Foaming agent

(D1) 1-Chloro-3,3,3-trifluoropropene (Manufacturer: Honeywell, Product name: Solstice LBA) was used.

(D2) Cyclopentane (CP, manufacturer: Yeocheon NCC, product name: cyclo-pentane) was used.

(E) Diphenylmethane diisocyanate

(E1) 4,4'-Diphenylmethane diisocyanate (P-MDI, manufacturer: BASF, product name: LUPRANATE M50) was used.

(E2) 4,4'-Diphenylmethane diisocyanate (P-MDI, manufacturer: BASF, product name: LUPRANATE M20S) was used.

Examples 1 to 3 and Comparative Example 1

As described in Table 1 below, lignin (B) and a phosphorus flame retardant (C) were added in a solution state to a polyester polyol (A) and a blowing agent (D), and these were mixed to prepare a polyol composition for producing a rigid polyurethane foam. Then, in the presence of a catalyst containing potassium 2-ethylhexanoate, under the temperature conditions of 50°C and the pressure conditions of 1.0 kgf/cm ² , diphenylmethane diisocyanate (E) was mixed into the prepared polyol composition for producing a rigid polyurethane foam to cause a reaction (free foaming) to prepare a rigid polyurethane foam. The physical properties of the prepared rigid polyurethane foam were evaluated by the following method, and the results are shown in Table 1 below.

Comparative Example 2

A polyol composition for producing a rigid polyurethane foam was prepared by simply mixing a polyester polyol (A), lignin (B), a phosphorus flame retardant (C), and a blowing agent (D) in the contents as shown in Table 1 below, and then, in the presence of a catalyst including potassium 2-ethylhexanoate, at a temperature of 50°C and a pressure of 1.0 kgf/cm2, diphenylmethane diisocyanate (E) was mixed into the prepared polyol composition for producing a rigid polyurethane foam to cause a reaction (free foaming), thereby preparing a rigid polyurethane foam. The physical properties of the prepared rigid polyurethane foam were evaluated by the following method, and the results are shown in Table 1 below.

Method of measuring physical properties

(1) Dispersed phase particle size of polyol composition (unit: ㎛): After preparing the polyol compositions of the examples and comparative examples, they were sealed and left for 7 days, and then one drop of each polyol composition was dropped on a slide glass, and a transparent cover glass measuring 2.5 cm × 2.5 cm was covered thereon, and the dispersed phase particle size was measured using an optical microscope (magnification: 10 to 20 times).

(2) Dispersed phase particle size of rigid polyurethane foam (unit: ㎛): The dispersed phase particle size was measured in a 10 cm × 10 cm × 1 cm sized specimen using an optical microscope (magnification: 10 to 20 times).

(3) Polyisocyanurate ratio (PIR ratio) and residual diphenylmethane diisocyanate ratio (MDI ratio): The polyisocyanurate ratio and residual diphenylmethane diisocyanate ratio of the rigid polyurethane foam were calculated according to Equations 1 and 2 below.

[Formula 1]

Polyisocyanurate ratio (PIR ratio) = PIR / (PUR + Urea + PIR + MDI)

[Formula 2]

Residual diphenylmethane diisocyanate ratio (MDI ratio) = MDI / (PUR + Urea + PIR + MDI)

In the above equations 1 and 2, PUR + Urea + PIR + MDI are FT-IR absorbance values of a phenyl group (range of 1,565 to 1,625 cm ^-1 ) commonly included in polyurethane, urea, polyisocyanurate, and diphenylmethane diisocyanate, PIR is an FT-IR absorbance value of a polyisocyanurate structure including an isocyanurate group (range of 1,340 to 1,465 cm ^-1 ), and MDI is an FT-IR absorbance value of an isocyanate group (range of 2,200 to 2,317 cm ^-1 ).

Here, FT-IR measurements were performed using the ATR mode of the iS50 model IR meter, a Thermo Scientific product, at room temperature in the range of 400 to 4,000 cm ^-1 at a resolution of 8 cm ^-1 . Specifically, the cross-section of the polyurethane foam specimen was brought into contact with the diamond cell of the ATR, and the screw at the top was turned so that the cross-section was in close contact with the meter, and then the measurement was performed. After the FT-IR measurement, the spectrum was measured using OMNIC Spectra software, and the absorbance peak value (FT-IR absorbance value) in the specified wavelength range was measured.

(4) Heat release rate (unit: MJ/ ^m2 ): The heat release rate of rigid polyurethane foam specimens was measured using a cone calorimeter (manufacturer: FESTEC, device name: Cone Calorimeter) according to KS F ISO 5660-1.

(5) Gas toxicity assessment: According to KS F 2271, the average behavioral arrest time of experimental mice was measured in a closed space injected with combustion gas from a rigid polyurethane foam specimen.

(6) Thermal conductivity (unit: W/m K): The thermal conductivity of rigid polyurethane foam specimens was measured according to KS M 3809.

Example Comparative example 1 2 3 1 2 (A) (weight) 100 100 100 100 100 (B) (Weight) 1.5 1.5 1.5 - 1.5 (C1) (weight) 20 20 20 20 20 (C2) (weight) 5.5 5.5 5.5 5.5 5.5 (D1) (Weight) 31 18.5 31 31 31 (D2) (Weight) - 8.5 - - - (E1) (Weight) 182 182 - 182 182 (E2) (weight) - - 182 - - Dispersed phase particle size of polyol composition (㎛) ≤ 30 ≤ 30 ≤ 30 ≤ 30 ≥ 600 Dispersed particle size of rigid polyurethane foam (㎛) ≤ 30 ≤ 30 ≤ 30 ≤ 30 ≥ 600 PIR ratio 5.7 5.8 5.6 5.4 5.8 MDI ratio 0.2 0.2 0.2 0.2 0.2 Heat release rate (MJ/m ² ) 5.5 7.0 5.8 5.8 6.0 Gas hazard assessment 10 minutes 3 seconds 9 minutes 40 seconds 9 minutes 30 seconds 7 minutes 30 seconds 7 minutes 45 seconds Thermal Conductivity (W/m K) 0.018 0.021 0.018 0.019 0.019

From the above results, it can be seen that the polyol composition for producing a rigid polyurethane foam of the present invention has excellent dispersion stability (particle size of the dispersed phase) even after 7 days from production, and the rigid urethane foam produced therefrom has excellent semi-non-combustibility (reduced heat release rate, reduced gas toxicity) and insulation (thermal conductivity).

On the other hand, in the case of Comparative Example 1 where lignin was not applied, it can be seen that the semi-non-combustibility (gas toxicity), etc. is reduced, and in the case of Comparative Example 2 where lignin and phosphorus flame retardant were not applied in a solution state, it can be seen that the dispersion stability, etc. of the polyol composition for producing rigid polyurethane foam is reduced, and it can be seen that the particle size of the dispersed phase including lignin exceeds the upper limit of the present invention, and the semi-non-combustibility (gas toxicity), etc. is reduced.

The present invention has been described with reference to embodiments. Those skilled in the art will understand that the present invention can be implemented in modified forms without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative rather than a restrictive perspective. The scope of the present invention is indicated by the claims, not the foregoing description, and all differences within the scope equivalent thereto should be interpreted as being included in the present invention.

Claims (15)

Isophthalic acid polyester polyol;
lignin; and
Including flame retardants;
A polyol composition for producing a rigid polyurethane foam, characterized in that the particle size of the dispersed phase as measured by an optical microscope is 30 ㎛ or less after 7 days from production.
In the first paragraph, the isophthalic acid-based polyester polyol is a polyol composition for producing a rigid polyurethane foam, characterized in that it is represented by the following chemical formula 1:
[Chemical Formula 1]

In the above chemical formula 1, L ₁ is a hydroxy group and A straight or branched chain alkylene group having 1 to 6 carbon atoms, substituted or unsubstituted by at least one of; or a hydroxyl group and A straight or branched chain ether group having 2 to 6 carbon atoms which is unsubstituted or substituted with at least one of; and L ₂ is a straight or branched chain alkylene group having 1 to 5 carbon atoms which is unsubstituted or substituted with a hydroxy group; or a straight or branched chain ether group having 1 to 5 carbon atoms which is unsubstituted or substituted with a hydroxy group; and m is an integer from 1 to 50 and n is an integer from 1 to 21.
A polyol composition for producing rigid polyurethane foam, characterized in that in claim 1, the isophthalic acid-based polyester polyol has a hydroxyl value (OH value) of 10 to 500 mgKOH/g.
A polyol composition for producing rigid polyurethane foam, characterized in that in claim 1, the isophthalic acid-based polyester polyol has a weight average molecular weight of 200 to 10,000 g/mol.
A polyol composition for producing a rigid polyurethane foam, characterized in that in claim 1, the phosphorus flame retardant comprises at least one of a liquid phosphorus flame retardant comprising at least one of triethyl phosphate, diethyl ethyl phosphonate, dimethyl methyl phosphonate, dimethyl propyl phosphonate, diphenyl cresyl phosphate, and tricresyl phosphate; and a halogenated phosphorus flame retardant comprising at least one of tris (1-chloro-2-propyl) phosphate, tris (2-chloroethyl) phosphate, tris (1,3-dichloropropyl) phosphate, tris (2,3-dibromopropyl) phosphate, and tetrakis (2-chloroethyl) ethylene diphosphate.
A polyol composition for producing rigid polyurethane foam, characterized in that in claim 1, the phosphorus flame retardant comprises a liquid phosphorus flame retardant.
A polyol composition for producing rigid polyurethane foam, characterized in that in claim 1, the phosphorus flame retardant comprises a liquid phosphorus flame retardant and a halogenated phosphorus flame retardant.
In claim 1, the polyol composition for producing a rigid polyurethane foam is characterized in that it comprises 100 parts by weight of the isophthalic acid-based polyester polyol; 0.5 to 7 parts by weight of the lignin; and 15 to 40 parts by weight of the phosphorus flame retardant.
In the first paragraph, the polyol composition for producing a rigid polyurethane foam is characterized in that it further contains 5 to 40 parts by weight of a blowing agent per 100 parts by weight of the isophthalic acid-based polyester polyol.
In claim 9, a polyol composition for producing a rigid polyurethane foam and a rigid polyurethane foam produced by mixing and reacting the polyol composition for producing a rigid polyurethane foam and diphenylmethane diisocyanate are characterized in that the particle size of the dispersed phase in a 10 cm × 10 cm × 1 cm specimen measured using an optical microscope is 30 ㎛ or less.
A polyol composition for producing rigid polyurethane foam, characterized in that in claim 10, the weight ratio of the isophthalic acid-based polyester polyol and the diphenylmethane diisocyanate is 1:1.5 to 1:3.
In claim 10, the polyol composition for producing a rigid polyurethane foam is characterized in that the polyisocyanurate ratio (PIR ratio) according to the following formula 1 is 4.5 to 7, and the residual diphenylmethane diisocyanate ratio (MDI ratio) according to the following formula 2 is 0.1 to 0.5:
[Formula 1]
Polyisocyanurate ratio (PIR ratio) = PIR / (PUR + Urea + PIR + MDI)
[Formula 2]
Residual diphenylmethane diisocyanate ratio (MDI ratio) = MDI / (PUR + Urea + PIR + MDI)
In the above equations 1 and 2, PUR + Urea + PIR + MDI are FT-IR absorbance values of a phenyl group (range of 1,565 to 1,625 cm ^-1 ) commonly included in polyurethane, urea, polyisocyanurate, and diphenylmethane diisocyanate, PIR is an FT-IR absorbance value of a polyisocyanurate structure including an isocyanurate group (range of 1,340 to 1,465 cm ^-1 ), and MDI is an FT-IR absorbance value of an isocyanate group (range of 2,200 to 2,317 cm ^-1 ).
A polyol composition for producing a rigid polyurethane foam, characterized in that in claim 10, the rigid polyurethane foam has a heat release rate of 3 to 8 MJ/ ^m2 as measured by a cone calorimeter according to KS F ISO 5660-1.
In claim 10, a polyol composition for manufacturing a rigid polyurethane foam is characterized in that the average behavioral cessation time of experimental mice in a closed space injected with combustion gas of a rigid polyurethane foam specimen measured according to KS F 2271 is 9 to 12 minutes.
A polyol composition for producing a rigid polyurethane foam, characterized in that in claim 10, the rigid polyurethane foam has a thermal conductivity of 0.017 to 0.024 W/m·K as measured according to KS M 3809.