HK1170752A - Polyester polyols made of isophthalic acid and/or terephthalic acid and oligoalkyl oxides - Google Patents

Description

Polyester polyols made from isophthalic and/or terephthalic acid and oligoalkylene oxides

Technical Field

The invention relates to a method for producing polyester polyols from isophthalic acid and/or terephthalic acid, oligoalkylene oxides and phthalic acid or phthalic anhydride, to the polyester polyols obtainable by this method, and to the use thereof for producing rigid PUR/PIR foams.

Background

Rigid PUR/PIR foams are nowadays predominantly produced from polyester polyols, since they have a positive influence on the flame retardancy of rigid PUR/PIR foams and on their thermal conductivity. In the preparation of polyester polyols, succinic acid, glutaric acid, adipic acid, phthalic acid/anhydride, terephthalic acid and isophthalic acid are mainly used as starting materials. In addition to polyester polyols, polyether polyols are also occasionally added to improve the solubility of pentane in the polyester polyol or to reduce the brittleness of rigid PUR/PIR foams containing isocyanurates.

However, the use of aromatic acids, in particular terephthalic acid, can lead to their presence in solid form at room temperature in the preparation of polyester polyols, thus making them more difficult to process in industrial processes.

To prepare these polyester polyols, U.S. Pat. No. 4,758,607 discloses using high molecular weight polyethylene terephthalate (PET) as the starting substrate and reprocessing it with a molecular weight reducing reaction medium, such as low molecular weight ethylene glycol, and in the presence of a low molecular weight polycarboxylic acid, to form a new polyester polyol. However, this method has the disadvantage that the PET first has to be collected in a complicated process. Furthermore, it must be ensured that the material is correctly sorted and not contaminated. When considering recycled materials, such as PET beverage bottles, the caps are usually made of polyethylene and require time consuming removal. Considering PET production waste, this raw material is not everywhere and is linked to the presence of PET production plants. A further disadvantage resides in the fact that, according to the teaching of US 4,758,607, part of the ethylene glycol used for the degradation of PET has to be removed again by distillation, which is disadvantageous in terms of energy in view of the high boiling point of ethylene glycol.

US 4,039,487 discloses polyester polyols based on terephthalic acid, tetraethylene glycol and phthalic anhydride. However, US 4,039,487 does not disclose how to overcome the disadvantages known to the person skilled in the art of esterification of these components, such as long reaction times due to poor solubility of terephthalic acid. Another disadvantage is that the number of available hydroxyl groups for the esterification of terephthalic acid decreases rapidly from the beginning of the reaction due to the rapid reaction of tetraethylene glycol with phthalic anhydride, which adversely affects the subsequent reaction of less reactive terephthalic acid, since its esterification rate is also proportional to the concentration of free hydroxyl groups. Thus, another approach is the use of larger amounts of esterification catalysts, since these catalysts can adversely affect subsequent reactions with these polyester polyols (e.g., the preparation of PUR foams).

Disclosure of Invention

It is therefore an object of the present invention to remedy the above-mentioned drawbacks of the prior art.

Many conventional rigid PUR/PIR foams are based on polyester polyols, which, however, are still not sufficiently flame-resistant, since they generally only achieve fire protection B3 ratings according to DIN 4102-1.

It is therefore an object of the present invention to provide polyester polyols which, when used in rigid PUR/PIR foams, improve the flame resistance, in particular for rigid PUR/PIR foams which achieve a fire protection B2 rating in accordance with DIN 4102-1 and/or SBI test (DIN EN 13823).

It is a further object of the present invention to provide a polyester polyol which is easy to process in an industrial process for producing rigid PUR/PIR foams and at the same time improves the flame retardancy of rigid PUR/PIR foams.

Detailed Description

The object of the present invention was surprisingly achieved by the process according to the invention for preparing polyester polyols, in which the ether group concentration is in the range from 9.0 mol/kg of polyester polyol to 22 mol/kg of polyester polyol, which process is characterized in that

(i) In the first step

(A) Isophthalic acid, optionally in C₁-C₄In the form of an alkyl ester, and/or terephthalic acid, optionally in C₁-C₄Form of alkyl ester, with

(B) Has a chemical formula of H- (OCH)₂CH₂)_n-OH, an oligoethylene glycol having a number average oxyethylene group number n in the range of 3.0-9.0,

the reaction is carried out at a temperature ranging from 160 ℃ to 240 ℃ and a pressure ranging from 1 mbar to 1013 mbar for a period of time ranging from 7 hours to 100 hours in the presence of at least one catalyst selected from the group consisting of tin (II) salts, bismuth (II) salts and titanium tetraalkoxides, and

(ii) in a second step, the reaction mixture obtained from step (i) is reacted with (C) phthalic acid and/or phthalic anhydride.

C of isophthalic acid₁-C₄Alkyl ester is represented byAn ester selected from dimethyl isophthalate, diethyl isophthalate, di-n-butyl isophthalate and diisobutyl isophthalate.

Preferably component (A) is terephthalic acid, optionally in the form of C₁-C₄In the form of an alkyl ester. C of terephthalic acid₁-C₄Alkyl ester means an ester selected from dimethyl terephthalate, diethyl terephthalate, di-n-butyl terephthalate and diisobutyl terephthalate.

Within the meaning of the invention, the general formula is H- (OCH)₂CH₂)_nIn the compound of-OH

n-1 has an oxyethylene group and no ether group;

n-2 has two oxyethylene groups, one ether group;

n-3 has three oxyethylene groups, two ether groups;

n-4 has four oxyethylene groups and three ether groups;

n-5 has five oxyethylene groups, four ether groups;

n-6 has six oxyethylene groups, five ether groups;

n-7 has seven oxyethylene groups, six ether groups;

n-8 has eight oxyethylene groups, seven ether groups;

n-9 has nine oxyethylene groups and eight ether groups.

Preferably, component (B) is a mixture of several oligoethylene glycols, n having the value of the formula H- (OCH)₂CH₂)_nThe average number of oxyethylene groups in component (B) is given in-OH. It is particularly preferred that component (B) of n ═ 2 contains less than 8% by weight of oligomers, particularly preferably less than 3% by weight. Thus, for values of n, it is also possible to obtain values which are not integers, for example 3.1, 3.2 or 3.24.

The number average molecular weight of the oligoethylene glycol (B) is preferably in the range from 145 to 450 g/mol, particularly preferably in the range from 150 to 250 g/mol.

The polyester polyols produced according to the process of the present invention preferably have an ether group content in the range of from 10 moles per kilogram of polyester polyol to 17 moles per kilogram of polyester polyol.

According to the invention, component (A) is preferably present in an amount of from 8 to 50% by weight, particularly preferably in an amount of from 10 to 35% by weight, based on the total amount of components A, B and C used for producing the polyester polyol.

According to the invention, component (B) is preferably present in an amount of from 50 to 92% by weight, particularly preferably in an amount of from 65 to 90% by weight, based on the total amount of components A, B and C used for producing the polyester polyol.

According to the invention, component (C) is preferably present in an amount of from 1 to 25% by weight, particularly preferably in an amount of from 1 to 22% by weight, most preferably in an amount of from 5 to 18% by weight, based on the total amount of components A, B and C used for the production of the polyester polyol.

The polyester polyols prepared by the process according to the invention preferably have hydroxyl numbers in the range from 100 mg KOH/g to 400 mg KOH/g, particularly preferably in the range from 110 mg KOH/g to 300 mg KOH/g, most preferably in the range from 150 mg KOH/g to 260 mg KOH/g,

the hydroxyl number of the polyester polyols can be determined on the basis of standard DIN 53240. The acid number of the polyester polyol can be determined on the basis of DIN 53402.

According to the invention, the molecular weight of the polyester polyol is preferably in the range of 280-.

The polyester polyols prepared by the process according to the invention preferably have an acid number in the range from 0.1 to 4 mg KOH/g, particularly preferably in the range from 0.15 KOH/g to 2.8 KOH/g.

The polyester polyols prepared by the process according to the invention preferably have a viscosity (measured to DIN 53019) in the range from 400 mPas to 10000 mPas at 25 ℃ and particularly preferably in the range from 500 mPas to 7000 mPas.

The oligoethylene glycol (B) preferably has an average number n of oxyethylene groups in the range from 3.1 to 9, particularly preferably in the range from 3.5 to 8.

The polyester polyols preferably have a melting point in the range from-40 ℃ to 25 ℃ and particularly preferably in the range from-20 ℃ to 23 ℃.

The polyester polyols according to the invention are preferably prepared from a mixture comprising

(i) In the first step, terephthalic acid (A) and a compound of formula H- (OCH)₂CH₂)_n-an oligo-ethylene glycol (B) having an average number of oxyethylene groups ranging from 3.0 to 9.0, and

(ii) in the second step, at least one component (C) is selected from phthalic acid and phthalic anhydride.

A preferred embodiment of the present invention is a process for preparing polyester polyols, wherein in a first step (i) components (A) and (B) are reacted in the presence of a catalyst selected from the group consisting of tin (II) salts, bismuth (II) salts and titanium tetraalkoxides at a temperature in the range from 160 ℃ to 240 ℃ and a pressure in the range from 1 to 1013 mbar for a time in the range from 7 to 100 hours.

Component (C) is preferably carried out only after 80 to 95% of the reaction water and optionally low molecular weight alcohols (such as methanol, ethanol, etc., i.e.those alcohols which are formed from the reaction of components (A) and (B)) have been distilled off in the first step (i). The reaction of the intermediate product obtained in step (i), formed from the reaction of components (A) and (B), with the component (C) added thereafter, i.e.step (ii), preferably takes place at a reaction temperature in the range from 160 ℃ to 240 ℃ and a pressure in the range from 1 to 150 mbar for a period of from 1 to 22 hours.

For the preparation of the polyester polyols according to the invention, all catalysts known to the person skilled in the art can be used. Preference is given to using tin (II) chloride, bismuth (II) chloride and titanium tetraalkoxides, such as titanium tetramethylalkoxide or titanium tetraethoxide. Particular preference is given to using tin dichloride dihydrate. These catalysts (optionally, the sum of the amounts used) are used in amounts of from 20 to 200ppm, most preferably from 45 to 80ppm, based on the sum of the parts by weight of all starting components A to C.

The reaction of the components for preparing the polyester polyols according to the invention preferably takes place in bulk (i.e. without addition of any solvent).

The present invention also provides a polyester polyol prepared according to the process of the invention and a process for preparing a PUR or PUR/PIR foam comprising the steps of:

a) reaction of at least one polyester polyol prepared according to the method of the invention with

b) At least one polyisocyanate-containing component,

c) at least one kind of foaming agent,

d) at least one or more catalysts selected from the group consisting of,

e) optionally, at least one flame retardant and/or other auxiliary substances and additives,

f) optionally, at least one compound having at least two isocyanate reactive groups.

As polyisocyanate-containing components, the customary aliphatic, cycloaliphatic and in particular aromatic di-and/or polyisocyanates are suitable. Toluene Diisocyanate (TDI), diphenylmethane diisocyanate (MDI) and, in particular, a mixture of diphenylmethane diisocyanate and polyphenylene polymethylene polyisocyanate (polymeric MDI) is preferably used. It is also possible to modify the isocyanates, for example by incorporating uretdione, carbamate, isocyanurate, carbodiimide, allophanate, in particular carbamate, groups. For the preparation of rigid polyurethane foams, use is made in particular of polymeric MDI. The isocyanurate formation in the prior art takes place virtually exclusively during the foam reaction and forms flame-retardant PUR/PIR foams which are preferably used in industrial rigid foams, such as in the building sector as insulation panels, sandwich elements, insulation pipes and truck bodies.

As compounds having at least two isocyanate-reactive groups, i.e. having at least two hydrogen atoms which are reactive with isocyanate groups, the following compounds described in general terms are generally used.

Compounds having at least two isocyanate-reactive groups, in particular those having two or more reactive groups in the molecule (selected from OH groups, SH groups, NH)₂Radicals and CH-acidic groups, such as beta-diketone groups) are suitable. For the preparation of rigid polyurethane foams which are preferably prepared by the process according to the invention, use is made in particular of compounds having from 2 to 8 OH groups. Preference is given to using polyether polyols and/or polyester polyols. In the preparation of rigid polyurethane foams, the polyether polyols and/or polyester polyols used preferably have hydroxyl numbers of from 25 to 850 mg KOH/g, particularly preferably from 25 to 550 mg KOH/g, and molecular weights of greater than 300 g/mol. Component (f) preferably comprises polyether polyols prepared by known methods, for example by anionic polymerization using bases hydroxide (e.g. sodium/potassium hydroxide) or alcoholates (e.g. sodium methylate, sodium/potassium ethylate or potassium isopropoxide) as catalyst and addition of at least one starter molecule containing 2 to 8, preferably 2 to 6, tethered reactive hydrogen atoms, or cationic polymerization using Lewis acids (e.g. antimony pentachloride, fluoroboric acid-diethyl ether complex, etc.) or clays as catalyst, the polyether polyols being derived from one or more alkoxides having 2 to 4 carbon atoms in the alkylene residue. Furthermore, the preparation of polyether polyols can be carried out by double metal cyanide-catalyzed reactions, in which case continuous operation is also possible.

Suitable alkylene oxides are, for example, tetrahydrofuran, 1, 3-propylene oxide, 1, 2-and 2, 3-butylene oxide, styrene oxide and preferably ethylene oxide and 1, 2-propylene oxide. The alkylene oxides may be used individually, alternately in sequence or as mixtures. Suitable starter molecules include, for example, glycerol, trimethylolpropane, pentaerythritol, sucrose, sorbitol, methylamine, ethylamine, isopropylamine, butylamine, benzylamine, aniline, toluidine, toluenediamine, naphthylamine, ethylenediamine, diethylenetriamine, 4, 4' -methylenedianiline, 1, 3-propanediamine, 1, 6-hexanediamine, ethanolamine, diethanolamine, triethanolamine and other dihydric or polyhydric alcohols, which may also be oligoether polyols or mono/polyvalent amines, and water.

In addition, component (f) may optionally comprise polyester polyols, chain extenders and/or crosslinkers. As chain extenders and/or crosslinkers, in particular difunctional or trifunctional amines and alcohols, in particular diols and/or triols, having molecular weights of less than 400 g/mol, preferably from 60 to 300 g/mol, are used. As component (f), preference is given to using polyether polyols and/or polyester polyols having a hydroxyl number of greater than 160, particularly preferably greater than 200 mg KOH/g, and particularly preferably having a functionality in the range from 2.9 to 8. Particular preference is given to using polyether polyols having an equivalent weight (i.e.molecular weight divided by functionality) of less than 400 g/mol, preferably less than 200 g/mol, as isocyanate-reactive compounds (f). The compounds (f) are usually present in liquid form.

As blowing agent component (c), preference is given to using hydrocarbons. These hydrocarbons may be used in admixture with water and/or other physical blowing agents. This means that the compound is dissolved or emulsified in the raw materials to prepare the polyurethane and evaporates under the conditions of polyurethane formation. They are, for example, hydrocarbons, halogenated hydrocarbons and other compounds, such as perfluoroalkanes, e.g.perfluorohexane, chlorofluorocarbons and ethers, esters, ketones and/or acetals.

The blowing agent component (c) is preferably used in amounts of from 2 to 45% by weight, preferably from 3 to 30% by weight, particularly preferably from 4 to 20% by weight, based on the total weight of components (b) to (f). In a preferred embodiment, the blowing agent mixture (c) comprises hydrocarbons, in particular n-pentane and/or cyclopentane, and water. Particularly preferred hydrocarbons are n-pentane, cyclopentane, isopentane and/or mixtures of isomers. Cyclopentane and/or n-pentane are used in particular as blowing agent (c).

According to the invention, for the preparation of polyurethane and polyisocyanurate foams, as catalyst (d) conventional and known polyurethane or polyisocyanurate forming catalysts are used, such as organotin compounds, for example tin diacetate, tin dioctoate, dibutyltin dilaurate, and/or strongly basic amines, for example 2, 2, 2-diazabicyclooctane, triethylamine or preferably triethylenediamine, N, N-dimethylcyclohexylamine or bis (N, N-dimethylaminoethyl) ether, and for the catalysis of the PIR reaction, potassium acetate, potassium octoate and aliphatic quaternary ammonium salts are used.

The catalyst is preferably used in an amount of from 0.05 to 3% by weight, preferably from 0.06 to 2% by weight, based on the total weight of all components.

The reaction of the abovementioned components optionally takes place in the presence of additives (e) such as flame retardants, fillers, cell regulators, foam stabilizers, surface-active compounds and/or stabilizers against oxidative, thermal or microbial degradation or ageing, preferably flame retardants and/or foam stabilizers. Substances capable of promoting the formation of a regular cell structure upon foam formation are referred to as foam stabilizers. Examples are as follows: silicon-containing foam stabilizers, such as siloxane-oxyalkylene copolymers and other organopolysiloxanes, and also alkoxylation products of fatty alcohols, oxo-alcohols, fatty amines, alkylphenols, dialkylphenols, alkylcresols, alkylresorcinols, naphthols, alkylnaphthols, naphthylamines, anilines, alkylanilines, toluidines, bisphenol A, alkylated bisphenol A, polyvinyl alcohols, and also alkoxylation products of polycondensation products of: formaldehyde and alkylphenols, formaldehyde and dialkylphenols, formaldehyde and alkylcresols, formaldehyde and alkylresorcinols, formaldehyde and anilines, formaldehyde and toluidines, formaldehyde and naphthols, formaldehyde and alkylnaphthols, and formaldehyde and bisphenol a. As alkoxylating agents, use may be made, for example, of ethylene oxide, propylene oxide, poly-THF and higher homologs.

Generally, flame retardants known in the art can be used as the flame retardant. Suitable flame retardants are, for example, brominated ethers (e.g. Ixol)B251) Brominated alcohols (e.g., dibromoneopentyl alcohol, tribromoneopentyl alcohol, and PHT-4-diol), and chlorinated phosphates (e.g., tris (2-chloroethyl) phosphate, tris (2-chloroisopropyl) phosphate (TCPP), tris (1, 3-dichloroisopropyl) phosphate, tris (2-chloroisopropyl) phosphate, tris (1, 3-dichloroisopropyl) phosphate, tris (2-chloroethyl) phosphate, tris (2-chloroisopropyl) phosphate, tris (1(2, 3-dibromopropyl) phosphate and tetrakis (2-chloroethyl) ethylene diphosphate). In addition to the halogen-substituted phosphoric acid esters already mentioned, inorganic flame retardants, such as red phosphorus, preparations containing red phosphorus, hydrated aluminum oxide, antimony trioxide, ammonium polyphosphate and calcium sulfate, or cyanuric acid derivatives, such as melamine, or mixtures of at least two flame retardants, such as ammonium polyphosphate and melamine, and optionally starch, can be used as flameproofing agents for the rigid PUR or PUR/PIR foams obtained according to the invention. As additional liquid halogen-free flame retardants, diethylethane phosphonate (DEEP), triethyl phosphate (TEP), dimethylpropyl phosphonate (DMPP), Cresyl Diphenyl Phosphate (CDP) and others can be used. The flame retardants used in the context of the present invention are preferably used in amounts of from 0 to 30% by weight, particularly preferably from 2 to 25% by weight, in particular from 2.5 to 15% by weight, based on the total weight of components (b) to (e).

More details of the above and other starting materials are known from the monographs, e.g.handbook of plastics, volume VII, Polyurethane, Karl Hanzel Press, Munich, Vienna, first edition, second edition and third edition 1966, 1983 and 1993 (Kunststoffhandbuch, vol.VII, Polyurethane, Carl Hanser Verlag Munich, Vienna, 1st, 2nd and 3rd editions 1966, 1983 and 1993)

To prepare rigid polyurethane foams, the polyisocyanate (b) and the component (a) and optionally (f) are reacted in amounts which satisfy the following conditions: the foams have an isocyanate index of from 90 to 600, preferably from 150 to 500, particularly preferably from 180 to 450.

The rigid polyurethane foams can be prepared by known methods in batch or continuous mode. Known to those skilled in the art, including but not limited to slabstock foam preparation (continuous and batch), use in single component systems (batch) and shaped insulating foams (batch). The invention described herein relates to all processes, but preferably a continuous double belt process, in which elastic and/or hard materials can be used for the cover layer.

The rigid polyurethane foams according to the invention preferably have a closed cell ratio of more than 90%, particularly preferably more than 95%.

The PUR and PUR/PIR foams according to the invention preferably have a density of from 28 g/m to 300 g/m, particularly preferably from 30 g/m to 50 g/m.

The rigid polyurethane foams according to the invention are used in particular for thermal insulation materials, such as cooling devices, containers or buildings, for example in the form of thermally insulated pipes, sandwich elements, thermally insulating panels or cooling devices.

The polyurethanes described in the present patent application are understood to also include polyisocyanate adducts which comprise, in addition to urethane groups, other groups, which can be formed, for example, as follows: the isocyanate groups are reacted with themselves, such as isocyanurate groups, or the isocyanate is reacted with groups other than hydroxyl groups, which are usually present in the polymer together with urethane groups.

The invention also provides the use of the above-described process for preparing polyester polyols for the preparation of polyurethanes. Polyurethane is a versatile material that has many applications. Due to the wide variety of raw materials available, products with drastic changes in properties can be prepared, such as rigid foams for thermal insulation, elastic block foams for mattresses, shaped elastic foams for automobile seats and cushions, acoustic foams for sound insulation, thermoplastic foams, shoe foams or microcellular foams, but also compression-cast systems and thermoplastic polyurethanes.

Example (b):

list of materials used in examples

Terephthalic acid: interquisa, Inc

Phthalic Anhydride (PA): industrial grade PA from Lanxess

PEG 200: BASF corporation

PEG 180: ineos Inc. of Neniu Europe

Ethylene Glycol (EG): ineos Inc. of Neniu Europe

Tin (II) chloride dihydrate: aldrich (Aldrich)

Titanium tetrabutylate: aldrich (Aldrich)

The equipment and analysis method used:

viscometer: MCR 51 from Armopa (Anton Paar)

Hydroxyl value: based on the standard DIN 53240

Acid value: based on the standard DIN 53402

A) Preparation of polyester polyols

Example a-1 (according to the invention):

in a 4 liter 4-neck flask equipped with a Pilz (Pilz) heating mantle, mechanical stirrer, internal thermometer, 40 cm packed column, column head, falling high efficiency condenser, and membrane vacuum pump, 2355 grams (11.78 moles) of PEG 200 were initially charged under nitrogen at 100 ℃. After about 5 minutes, 412 grams (2.48 moles) of terephthalic acid were added with stirring, and 78 milligrams of stannous chloride dihydrate were added. The mixture was heated to 230 ℃ for 5 hours, at which time water was distilled off and the haze in the reaction mixture disappeared. Thereafter 367 g (2.48 mol) Phthalic Anhydride (PA) were added and the mixture was heated to 230 ℃ and held for 4 hours. A further 78 mg of tin dichloride dihydrate were then added and a vacuum was applied, finally maintained at a level of 60 mbar. Under these conditions, the polycondensation reaction can be continued for 15 hours. The product was cooled and its properties were determined:

analysis of polyester:

hydroxyl value: 236.6 mg KOH/g

Acid value: 0.2 mg KOH/g

Viscosity: 720 mPa s (25 ℃ C.)

The polyesters according to the other examples A-2 to A-4 and A-6(C) of the present invention were prepared in a similar manner.

Example a-5 (control):

in a 4 liter 4-neck flask equipped with a piltz heating mantle, mechanical stirring, internal thermometer, 40 cm packed column, column head, falling high efficiency condenser, and membrane vacuum pump, 1444 g (9.76 moles) of PA are initially charged at 180 ℃. After about 30 minutes 1034 g (9.76 mol) of diethylene glycol are added and the mixture is stirred for 60 minutes at 180 ℃. 356 g (2.44 mol) of adipic acid and 429 g (6.92 mol) of ethylene glycol were then added. The mixture was distilled off with water at standard pressure for 3.5 hours. 65 mg of tin dichloride dihydrate were added and the reaction was terminated after 30 hours at 200 ℃ and 70 mbar, after which 352 g (3.32 mol) of diethylene glycol were added and the mixture was allowed to react for a further 6 hours at 200 ℃ and standard pressure. The product was cooled and its properties were measured.

Analysis of polyester:

hydroxyl value: 235.2 mg KOH/g

Acid value: 0.7 mg KOH/g

Viscosity: 9150 mPa s (25 ℃ C.)

Comparative examples A-5 and A-6 are not according to the invention, since neither terephthalic acid nor oligoethylene glycol was used in A-5 (control) and the ether group proportion of the oligoethylene glycol was less than 9 mol/kg ester in A-5 (control) and A-6 (control). Furthermore, A-6 (control) was not liquid at room temperature.

Rigid PUR/PIR foam raw material:

a.) the polyesters of examples A-1, A-2, A-3, A-4 and A-5 (C).

A foam additive comprising b.) -f.):

b.) TCPP, tris (1-chloro-2-propyl) phosphate from Lanxess

c.) TEP, triethyl phosphate from Levagard

d.) additives 1132 from Bayer materials science (Bayer Material science)

e.) PET V657, a trifunctional polyether polyol having a molecular weight of about 660 daltons from Bayer materials science AG

f.) stabilizer polyether-polysiloxane copolymer from Evonik

The foam additives (b-f) shown in Table 2 comprise 20 parts by weight of component (b), 5 parts by weight of component (c), 2.2 parts by weight of component (d), 5 parts by weight of component (e) and 4 parts by weight of component (f).

Activator (g) carboxylate (PIR catalyst): desmorapidPU 30HB13 from Bayer materials science, Inc. (Lewakusen, Germany)

Isocyanate: (h) desmodurPU 44V70L, polymeric polyisocyanates, based on 4, 4' -diphenylmethane diisocyanate, having an NCO content of about 31.5% by weight, from Bayer materials science, Inc. (Levokusen, Germany)

Blowing agent (i) n-pentane, Kremer & Martin.

The index represents the molar ratio of all isocyanate groups to all zerewittinof active hydrogen atoms.

On a laboratory scale, all the raw materials for forming the rigid foams, with the exception of the polyisocyanate component, were weighed in a paper cup, the temperature was controlled at 23 ℃ and mixed with a Australian-gram (Pendra Ik) laboratory mixer (e.g.type LM-34 from Australian-gram (Pendra Ik)), optionally with the addition of a volatile blowing agent (pentane). The polyisocyanate component was then added to the polyol mixture with stirring (again the temperature was controlled at 23 ℃), and after vigorous stirring the reaction mixture was poured into paper-lined wooden moulds. In the foam formation, the setting time and the open time are determined. After 24 hours, a cube-shaped specimen having a length of 9 cm was cut out of the foam cell.

The following properties were measured:

dimensional stability: determined by measuring the change in dimensions of the cuboidal specimen after storage at +80 ℃ for 24 hours. The foams according to the invention exhibit a change of not more than 1% (absolute) in relative length for each spatial direction.

Nuclear density: determined by the volume and weight of the cut cube specimen.

KBT: the sodium Clarithromium (Kleinbrenner) test (small oven test) was carried out in accordance with DIN 4102-1. The rigid foam of the present invention achieves fire protection rating B2.

BVD test: the combustibility of the construction materials was determined according to Swiss Basic Test from Vereinigung kantonner Feuerversacherung [ State fire insurance Association ], 1988 edition, and 1990, 1994, 1995 and 2005 supplementations (available from Vereinigung kantonner Feuerversacherung, Bunesstr.20, 3011, Burrni, Switzerland).

Setting time: determined by dipping a wooden stick into the reaction polymer melt and removing. The time for the polymer melt to harden was characterized.

Surface drying time: the foam surface conditions were characterized. Determined by tapping with a wooden stick the foam that no longer grows. The time when the material no longer adheres is called the open time.

Claims (15)

1. A process for preparing polyester polyols having a concentration of ether groups in the range from 9.0 mol/kg of polyester polyol to 22 mol/kg of polyester polyol, characterized in that

(i) In the first step

(A) Isophthalic acid, optionally as C₁-C₄In the form of an alkyl ester, and/or terephthalic acid, optionally in C₁-C₄Form of alkyl ester, with

(B) Has a chemical formula of H- (OCH)₂CH₂)_n-OH oligo ethylene bisAlcohol reaction, the number average oxyethylene group number n of the oligoethylene glycol is 3.0-9.0,

the reaction is carried out in the presence of at least one catalyst selected from the group consisting of tin (II) salts, bismuth (II) salts and titanium tetraalkoxides at a reaction temperature of 160-240 ℃, a reaction pressure of 1-1013 mbar and a reaction time of 7-100 hours, and

(ii) in a second step, the reaction mixture obtained from step (i) is reacted with

(C) Phthalic acid and/or phthalic anhydride.

2. The process of claim 1, wherein component (a) is present in an amount of from 8 to 50 wt.%, based on the total amount of the mixture.

3. The process according to claim 1 or 2, wherein component (B) is present in an amount of 50 to 92% by weight, based on the total amount of the mixture.

4. The process according to any one of claims 1 to 3, wherein component (C) is present in an amount of from 1 to 25% by weight, based on the total amount of the mixture.

5. The method of any one of claims 1-4, wherein the polyester polyol has a hydroxyl number of from 100 mg KOH/g to 400 mg KOH/g.

6. The process according to any one of claims 1 to 5, wherein the polyester polyol has a viscosity, measured according to DIN 53019, of from 400 mPa s to 10000 mPa s at 25 ℃.

7. The process according to any one of claims 1 to 6, wherein the oligoethylene glycol (B) has a number average number n of oxyethylene groups of 3.1 to 9.

8. The method of any one of claims 1-7, wherein the polyester polyol has a melting point of-40 ℃ to 25 ℃.

9. The process of any one of claims 1 to 8, wherein components (A) and (B) are reacted in the presence of at least one catalyst selected from the group consisting of tin (II) chloride, bismuth (II) chloride, titanium tetramethoxide and titanium tetraethoxide.

10. The process according to any one of claims 1 to 9, wherein the sum of the amounts of the catalysts selected from the group consisting of tin (II) salts, bismuth (II) salts and titanium tetraalkoxides is from 20 to 200ppm, based on the sum of the parts by weight of all starting components a to C.

11. A polyester polyol obtained from the process of any one of claims 1 to 10.

12. Use of the polyester polyols according to claim 11 for producing PUR or PUR/PIR foams.

13. A process for preparing a PUR or PUR/PIR foam, which process comprises the following steps

a) Reacting at least one polyester polyol according to claim 11 with

b) At least one polyisocyanate-containing component,

c) at least one kind of foaming agent,

d) at least one or more catalysts selected from the group consisting of,

e) optionally, at least one flame retardant and/or other auxiliary substances and additives,

f) optionally, at least one compound having at least two isocyanate reactive groups.

14. A PUR or PUR/PIR foam obtained from the process of claim 13.

15. Use of the PUR or PUR/PIR foam obtained from the process of claim 13 for the preparation of insulated pipes, sandwich elements, insulation panels or cooling devices.