JP2002529558A - Polyethylene naphthalate polyester polyol and rigid polyurethane foam obtained therefrom - Google Patents

Abstract

  (57) [Summary] a) depolymerizing a poly (alkylene polyaromatic dicarboxylate) in the presence of a glycol and then b) adding a polycarboxylic acid, anhydride or ester and / or polyhydric alcohol. Poly (alkylene polyaromatic dicarboxylate) ester-containing polyester polyols comprising transesterifying the product obtained, and thus obtained in the production of rigid polyurethane foams and urethane-modified polyisocyanurate foams Use of polyester polyols.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to the production of polyester polyols based on poly (alkylene polyaromatic dicarboxylate) esters and their use in the production of rigid polyurethane and polyisocyanurate foams.

In particular, the present invention relates to polyester polyols produced by reacting polyethylene naphthalate. It is known to produce rigid polyurethane (PUR) and polyisocyanurate (PIR) foams by reacting polyisocyanates, polyols and blowing agents in the presence of a catalyst. A wide variety of polyols have been used as one of the components in the production of rigid polyurethane foams, including polyols from various waste streams.

[0003] The polyols are usually polyether alcohols or polyester alcohols, or a mixture of the two. Both aliphatic and aromatic polyester polyalcohols are used. These are reaction products obtained by esterifying dicarboxylic acids or anhydrides with glycols (primary / secondary). Transesterification methods are also often used. Aromatic polyester polyols used in rigid PUR / PIR foams are typically used in the production of dimethyl terephthalate (DMT) product waste.
on waste) flow. Polyethylene terephthalate (PET) scrap is also a source of aromatic carboxylate. Depolymerization of post-consumer waste or production waste streams, for example from PET bottles, is a known method in the production of polyester polyols.

[0004] Currently available polyols produced from scrap PET or DMT process residues have various disadvantages, such as, for example, incompatibility with the blowing agents commonly used in the production of rigid PUR / PIR foams. is there. Foams made from these polyols may have incomplete compressive strength and / or insulation and / or flame resistance.

It has been found that poly (ethylene naphthalate) (PEN) easily depolymerizes, and that a polyester polyol having a high aromatic content can be produced based on the depolymerized product. Rigid polyurethane foam or polyisocyanurate foam produced using this polyester polyol has excellent mechanical stability and good fire resistance
(fire performance), low smoke generation and low thermal conductivity.

[0006] Poly (alkylene polyaromatic dicarboxylates) preferably used in the present invention
The ester is poly (ethylene 2,6-naphthalate). Other isomers of this polymer, or poly (ethylene terephthalate) (PET), poly (butylene terephthalate)
) (PBT) or a copolymer with poly (butylene naphthalate), and a polycyclic structure (
For example, polyesters based on dicarboxylates with (anthracene, phenanthrene) and copolymers thereof can also be used.

[0007] The polyester polyol is produced by a two-step process. In the first step, the polyester is depolymerized in the presence of a glycol. The glycol can be, for example, 1,4-butanediol, diethylene glycol (DEG) or dipropylene glycol (DPG). DEG is most suitable as the diol, which is preferably used in the excess required for digestion. The reaction occurs in the absence of a catalyst, but the use of a suitable catalyst significantly reduces the reaction time. A preferred catalyst is tetra-N-butyl titanate (TBT). Zinc oxide or manganese acetate can also be used.

[0008] The depolymerization is carried out at a temperature at which the polyester dissociates and a core unit is obtained. This is usually carried out in a temperature range from 150 to 350 ° C, preferably about 240 ° C. This method is usually performed at ambient pressure. However, it is also clear that pressures higher than ambient pressure can be used. The higher the pressure, the more significantly the reaction temperature can be raised, thus shortening the reaction time. The resulting reaction mixture contains the esterification product from the polyaromatic dicarboxylate and the glycol used, as well as the diol of the alkyl chain between the aromatic rings. Very often, excessive amounts of glycols are incorporated. Starting from PEN, the product from this first stage contains PEN-derived naphthalate polyols, unreacted glycols and ethylene glycol. During the depolymerization and the esterification, it is also possible to remove the ethylene glycol formed by vacuum distillation. This usually results in a lower OH number of the final polyester polyol and a lower aliphatic content, which is reflected in the fire resistance of the resulting foam. The present invention did not remove this ethylene glycol, but did not adversely affect the final rigid foam properties.

In a second step, the mixture is further transesterified by adding other polycarboxylic acids, anhydrides or esters and polyhydric alcohols. This further transesterification brings the final polyester polyol into the desired viscosity range. The total content of the polyester polymer used in the synthesis of the polyester polyol is usually in the range of 5 to 50% by weight, preferably 10 to 40% by weight. The polycarboxylic acids and polyhydric alcohols are added at a temperature in the range from 80 to 240C, preferably at 100 to 180C.

Preferable examples of the polycarboxylic acid component or its derivative include adipic acid, glutaric acid and its anhydride, succinic acid, oxalic acid, malonic acid, suberic acid, azelaic acid,
Sebacic acid, phthalic acid, phthalic anhydride and pyromellitic anhydride are exemplified. As polyhydric alcohols, glycols are preferred. These may be general formula C _n H _2n (OH) ₂ in a simple glycol or the general formula _{C n H 2n O x (OH} ) polyglycols having intervening ether linkage as represented by _2. They can also contain heteroatoms.

[0011] The polycarboxylic acid component and the polyhydric alcohol can contain substituents that are inert in the reaction, such as chlorine and bromine substituents, and / or can be unsaturated. Examples of suitable polyhydric alcohols include alkylene glycols and oxyalkylene glycols such as ethylene glycol, diethylene glycol and higher polyethylene glycols, propylene glycol, dipropylene glycol and higher propylene glycols, glycerol, pentaerythritol, Methylolpropane, sorbitol and mannitol.

The above two steps can also be performed in a single step method. Using the two-step method, the depolymerization of the polyester polymer is more complete and faster. The final polyol mixture for use in the present invention has an average functionality of 1.5-8, preferably 2-3. The hydroxyl value is usually from 200 to 550 mg KOH / g polyol. The molecular weight of the polyester usually ranges from 200 to 3000, preferably from 200 to 1000, most preferably from 200 to 800.

The term polyester polyol as used in the present invention is intended to include any small amount of unreacted and / or unesterified polyol remaining after the polyester polyol is produced.

The polyester polyols according to the invention are used to produce rigid polyurethane-based foams. In processing polyurethane and polyisocyanurate foams, the polyisocyanates and the mixture of isocyanate-reactive components are usually mixed in a one-shot method. Both high pressure and low pressure methods can be used in the mixing stage. The proportion of NCO / OH groups usually ranges from 0.85 to 1.40, preferably 0.95 to 1.2 for polyurethane foams and from 50 to 1, preferably 8 to 1 for polyisocyanurate foams. .

In addition to the PEN-based polyester polyols of the present invention, other isocyanate-reactive compounds can be used in the process for producing rigid polyurethane foams or urethane-modified polyisocyanurate foams. Suitable isocyanate-reactive compounds include any known in the art for making rigid polyurethane foams, especially those of the other types of polyether polyols and polyester polyols.

[0016] Typically, the PEN-based polyester polyols of the present invention comprise 60 to 100% by weight of the total isocyanate-reactive compounds. The isocyanate-reactive mixture usually contains polyhydric alcohols and other optional additives such as blowing agents, flame retardants, fillers, stabilizers, catalysts and foam stabilizers. Preferred catalysts for polyurethane production are amines, with tertiary amines being most preferred. Dibutyltin dilaurate is an example of a non-amine based polyurethane catalyst. Preferred polyisocyanurate catalysts are alkali metal carboxylates and quaternary ammonium carboxylates.

Any blowing agent known in the art for producing rigid polyurethane or urethane-modified polyisocyanurate foams can be used in the method of the present invention. Both physical and chemical blowing agents can be used alone or in combination.

Suitable physical blowing agents include, for example, hydrocarbons, dialkyl ethers, alkyl alkanoates, aliphatic and cycloaliphatic hydrofluorocarbons,
There are hydrochlorofluorocarbons, chlorofluorocarbons, hydrochlorocarbons, fluorine-containing ethers and carbon dioxide. Examples of preferred blowing agents include isomers of pentane, such as cyclopentane, n-pentane and isopentane, and mixtures thereof, 1,1-dichloro-2-fluoroethane (HCFC 141b
), 1,1,1-trifluoro-2-fluoroethane (HFC 134a), chlorodifluoromethane (HCFC 22), and 1,1-difluoro-3,3,3-trifluoropropane (HFC 245fa).

[0019] The carbon dioxide release product can be used as a chemical blowing agent. Water that releases carbon dioxide upon reaction with isocyanates is widely known as a chemical blowing agent.

[0020] The total amount of blowing agent is usually from 0.1 to 25% by weight, based on the total reaction system. Both aliphatic and aromatic polyisocyanates can be used. Aromatic polyisocyanates such as diphenylmethane diisocyanate
(MDI) and toluene diisocyanate (TDI) or prepolymers thereof are preferred. Mixtures of isomers and oligomers can also be used. The polymeric form of MDI is most preferred.

The polyisocyanate can be a modified uretonimine or carbodiimide. The present invention is illustrated by the following non-limiting examples.

Examples 1-3: Synthesis of Polyester A 2-liter flask equipped with an efficient stirrer, thermocouple and distillation apparatus was charged with diethylene glycol and polyethylene 2,6-naphthalate. 10 ppm of TBT was added. The contents were heated to 240 ° C. under a nitrogen atmosphere with efficient stirring. 2
After ３3 hours, the temperature was reduced to 160 ° C. and charged with adipic acid and glycerol along with 10 ppm TBT (see Table 1 for amounts). The mixture was heated slowly to 180 ° C. and water was removed by distillation. To complete the esterification, the temperature was further increased to 200 ° C. until the theoretical amount of water had distilled off under vacuum. When the distillation rate became flat, an acid value titration was performed. An acid number of 2 mg KOH / gram is acceptable.

The characteristics of the obtained polyesters are shown in Table 1.

[0024]

[Table 1]

Examples 4-7 Rigid urethane-modified polyisocyanurate foams were prepared from the polyesters prepared according to Examples 1-3 above. The ingredients (400 grams) were agitated at 5000 rpm in a small scale lab mixer and poured into a 20 × 20 × 30 cm open mold. HCFC 141b was used as a blowing agent. After standing at room temperature for at least 24 hours, the foam was tested for physical properties. The physical properties obtained with the components (parts by weight) and the polyols A, B and C, and comparative examples based on PET polyols, are listed in Table 2.

PET Polyol: Scrap PET-based polyester polyol, OH value 350 mgK
OH / gram. Tegostab B 8406: a silicone-based foam stabilizer from Goldschmidt.

TEP: triethyl phosphate flame retardant. DMEA: dimethylethanolamine catalyst. Niax AI: bis (dimethylaminoethyl ether) catalyst.

Dabco K15: potassium octylate catalyst. SUPRASEC 2085: Polymer MDI made by Huntsman Polyurethanes (SUPRASEC is Hun
tsman is a trademark of ICI Chemicals LLC).

CT: cream time. This is the time from mixing until the appearance of the mixed reagent changes, indicating the start of swelling. ST: String time. This is the time from mixing until the polymer thread can be pulled from the reaction mixture using a spatula.

ER: End of rise time. This is the time from mixing to the end of foam expansion. TF: tack free time. This is the time from mixing until the spatula does not stick to the foam surface under light pressure.

The density was measured according to standard DIN 53420. Thermal conductivity was measured according to standard ISO 2581. The compressive strength was measured according to standard DIN 53421.

The Kleinbrenner number was determined according to standard DIN 4102. The Limited O ₂ index was measured according to standard ASTM 2863. NBS Smoke value was measured according to standard ASTM E662.

Examples 8-11 Rigid urethane-modified polyisocyanurate foams were prepared from the polyesters made according to Examples 1-3 above. The ingredients (400 grams) were mixed at 5000 rpm and poured into a 20 × 20 × 30 cm open mold. Isopentane was used as a blowing agent. After standing at room temperature for at least 24 hours, the resulting foam was tested for physical properties. The physical properties of the foams obtained using the components (parts by weight) and the polyols A, B and C and comparative examples of PET-based polyols are listed in Table 3.

[0034]

[Table 2]

[0035]

[Table 3]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) C08L 67:00 C08L 67:00 (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SL, SZ, TZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU) , TJ, TM), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, E S, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU , LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZA, ZWF terms (reference) 4F301 AA25 AB03 BF31 CA07 CA23 CA41 CA71 4J029 AA01 AB04 AD01 AD03 AD10 AE17 BA03 BA05 BA08 BF09 BF10 CA01 CA02 CA03 CA04 CA05 CA06 CB04A CC06 FC03 FC03 FC03 FC03 FC05 FC38 JB131 JE162 JE182 JF321 KG02 KG03 4J034 BA03 CA01 CA04 CA05 DB03 DB04 DE04 DF01 DF14 DF15 DF17 DF19 DF21 DG01 DG02 DG03 DG04 HA01 HA06 HA07 HB05 HB06 HC11 HC12 HC52 HC61 HC63 Q01 HC12 K07 HC07 K07 HC12 K11 QB01 QB14 QB16 QC01

Claims (9)

[Claims] 1. A method comprising: a) depolymerizing a poly (alkylene polyaromatic dicarboxylate) in the presence of a glycol; A process for producing a polyester polyol based on a poly (alkylene polyaromatic dicarboxylate) ester, comprising transesterifying the product obtained by addition. 2. The method according to claim 1, wherein the poly (alkylene polyaromatic dicarboxylate) is poly (alkylene polyaromatic dicarboxylate).
2. The method according to claim 1, wherein the compound is ethylene 2,6-naphthalate). 3. The method of claim 2, wherein the poly (ethylene 2,6-naphthalate) is from a production waste stream or post-consumer waste. 4. The method according to claim 1, wherein the glycol used in step a) is diethylene glycol. 5. Step a) in the presence of tetra-N-butyl titanate as a catalyst
The method according to claim 1, wherein the method is performed. 6. The polyester polyol has an average functionality of 1.5 to 8 and a hydroxyl value of 2.
The method according to any one of claims 1 to 5, having a molecular weight of 200 to 3000 and a molecular weight of 200 to 3000 mg KOH / g. 7. A polyester polyol obtained by the method according to claim 1. 8. A process for producing a rigid polyurethane foam or a urethane-modified polyisocyanurate foam by reacting an organic polyisocyanate with a polyfunctional isocyanate-reactive composition in the presence of a blowing agent, said method comprising: The method according to claim 7, characterized in that the polyfunctional isocyanate-reactive composition comprises the polyester polyol according to claim 7. 9. The method of claim 8, wherein said polyester polyol comprises 60 to 100% by weight of the total isocyanate-reactive compound.