WO2006040251A1

WO2006040251A1 - Process for making a pipa-polyol

Info

Publication number: WO2006040251A1
Application number: PCT/EP2005/054763
Authority: WO
Inventors: Gabriel Albert Verhelst; Jianming Yu
Original assignee: Huntsman International LLC
Current assignee: Huntsman International LLC
Priority date: 2004-10-15
Filing date: 2005-09-23
Publication date: 2006-04-20
Anticipated expiration: 2007-04-15
Also published as: AU2005293677B2; TW200621823A; CN101039974B; CA2581506A1; ES2339468T3; US20070265411A1; AU2005293677A1; KR20070063002A; RU2386644C2; ATE455137T1; DE602005018955D1; BRPI0516579A; US7674853B2; CN101039974A; EP1809679A1; JP2008517084A; KR101206647B1; RU2007117922A; MX2007004334A; EP1809679B1

Abstract

Process for preparing a polyol comprising particulate material in dispersed form by reacting an MDI-based polyisocyanate and a polyol having an equivalent weight of up to 400 in a relative amount such that the number of NCO-groups is 70-100% of the number of OH-groups in said polyol having an equivalent weight of up to 400, the reaction being carried out in a polyol having an equivalent weight of 500 or more. The polyols are claimed as well.

Description

[0001] Process for making a PIPA-polyol

[0002] The present invention is concerned with a process for preparing PIPA

polyols. PIPA (polyisocyanate polyaddition) polyols have been disclosed

before, see e.g. US 4452923, US 4438252, US 4554306, GB 2102822,

GB 2072204, WO 94/12553, US 5292778 and EP 418039. PIPA polyols

are polyaddition reaction products of a polyisocyanate and a low molecular

weight compound having a plurality of hydroxyl, primary amine and/or

secondary amine groups in the presence of high molecular weight polyols,

in particular polyether polyols. The PIPA polyol is a dispersion of

particulate material in a polyol and is used e.g. in making slabstock or

moulded flexible foams with improved load-bearing properties. The

amount of PIPA polyol used in formulations for making such foams

conventionally is such that the amount of particulate material calculated on

all high molecular weight polyol used in the formulation is 1-15% by

weight. The most commonly used PIPA polyol nowadays probably is a

PIPA polyol having about 20% by weight of particulate material, which is

diluted with further high molecular weight polyol to the above 1-15% by

weight loading range.

[0003] It would be desirable to be able to provide PIPA polyol with a considerably

higher loading. It would allow the foam producer to use PIPA polyol with

higher loadings for making the foam. Even if the foam producer would dilute the PIPA polyol with a higher loading, it would have the advantage

that the PIPA polyol can be transported in a more concentrated form and

can be diluted at the place where it is needed and to the extent needed.

Further it provides the polyurethane systems' formulator with less

formulation restrictions. The foams made from such PIPA polyols show

good fire retardancy properties and are easily recyclable chemically.

[0004] Processes for making such PIPA polyols, with a higher loading, are

known, see e.g. the prior art mentioned before. However these processes

lead to products which have a high viscosity and/or are not stable or these

processes lead, certainly at a larger scale, to an uncontrollable reaction

which gives PIPA polyols which could cause foam collapse when used in

making flexible polyurethane foams.

[0005] In WO 00/73364 a process is described for preparing a PIPA-polyol having

a loading of 30-80% by weight and a relatively low viscosity. The Tg

(glass transition temperature) of such PIPA polyols is relatively low and the

amount of particles having a particle size of 10 μm and more is rather high,

leading to lower storage stability. When used in making flexible foams

such PIPA polyols give a cell opening effect which often is too strong and

a reinforcing effect which is too low; further the compression set and the

fire performance of the foam would need improvement.

The PIPA polyol obtained in the example of WO 00/73364 had a solids

content of 50% by weight and a viscosity of 15000 mPa.s at 25⁰C. The T₉ of the particulate material, however, was only 68⁰C and up to 15% by

volume of the particles had a particle size of more than 10 μm.

Surprisingly, a novel PIPA polyol was found having a higher T₉ of the

particulate material and a higher volume of the particles having a particle

size of 10 μm or less. Such a novel PIPA polyol is made by a combination

of measures: 1) the ratio of isocyanate groups and isocyanate-reactive

groups in the low molecular weight polyol was increased (in the example

of WO 00/73364 this ratio was 61/100 while in the specification a range of

33-99/100 and preferably of 50-80/100 has been proposed; in the process

according to the present invention this ratio is 70-100/100 and preferably

75-98/100); 2) emulsification of the polyol having a high molecular weight

and the isocyanate-reactive compound having a low molecular weight

preferably is conducted at a lower temperature (in WO 00/73364 a

temperature of 60-100⁰C and preferably of 70-95⁰C has been disclosed

and 82-85⁰C was employed in the example and in the present invention

preferably 20-70⁰C is employed); 3) temperature control according to the

following

- during the entire process the temperature may not exceed 15O⁰C;

- during the entire process the temperature may not exceed 12O⁰C for

more than 2 hours and preferably for not more than one hour;

- during the addition of the polyisocyanate the temperature is kept at

least 10⁰C and preferably at least 2O⁰C and most preferably at least 3O⁰C above the T₉ of the PIPA particle formed at that stage of the

process; and finally

4) the addition time of the polyisocyanate preferably is kept as short as

possible and is determined by the cooling capacity available so as to

keep the temperature within the above given limitations.

In this respect it is to be realised that the T₉ of the PIPA particles

increases with the amount of polyisocyanate added almost linearly to

about 75-110⁰C at the end of the addition.

[0006] As such, reinforced polyols having a higher Tg have been disclosed.

[0007] For instance US 5916994 and US 4208314 disclose polymer polyols

based on styrene and acrylonitrile (SAN) having a Tg of about 100⁰C.

However so far no such PIPA polyols have been disclosed. In addition a

narrow particle distribution and a high amount of small particles in the past

could most of the time only be obtained following mechanical filtration.

The present invention provides for a PIPA polyol with a high T₉ and a high

amount of small particles without the need of such mechanical filtration.

[0008] Therefore, the present invention is concerned with a polyol composition,

comprising particulate material in dispersed form in a polyol having an

average equivalent weight of 500 or more and in an amount of 35-80% by

weight and preferably of 40-60% by weight calculated on the total polyol

composition, this composition having a viscosity of 1500-25000 mPa.s at

25⁰C and the particulate material comprising reaction products of a polyol having an average equivalent weight of up to 400 and of diphenylmethane

diisocyanate optionally comprising homologues thereof having an

isocyanate functionality of 3 or more and/or modified variants of such

polyisocyanates, the particulate material having a glass transition

temperature of at least 75⁰C and at least 90% by volume of the particulate

material having a particle size of 10 μm or less.

[0009] Such a glass transition temperature (Tg) is determined by Differential

Scanning Calorimetry (DSC) measurements which are carried out over a

- 2O⁰C to 200°C temperature range with a heating rate of 10°C/min. The

Tg value is recorded at the inflection point of the heat capacity jump.

Preferably the polyol composition has a glass transition temperature of at

least 8O⁰C.

[0010] The viscosity is measured using a Brookfield Viscometer, model DV-II with

a spindle CP-41.

[0011] Further the polyol composition according to the present invention

preferably comprises particulate material of which at least 95% by volume

has a particle size of 10 μm or less (particle size is measured using a

Mastersizer 2000, from Malvern Instruments, equipped with a Hydro

2000/s dispersion accessory, using methanol as eluent) and most

preferably at least 95% by volume has a particle size of 5 μm or less. The

content of particulate material is the sum of the amount of polyisocyanate

and the amount of polyol having an equivalent weight of up to 400 used in making the polyol composition according to the present invention and is

calculated by the following formula:

(weight of polyisocyanate + weight of polyol with eq. weight of up to 4Oθ)l 00 %w. total weight of the polyol composition

[0012] It will be clear that in this calculation it is assumed that all reacted product

gives particulate material and that no polyisocyanate reacts with the other

polyol (s).

[0013] Further the present invention is concerned with a process for preparing the

above polyol composition by emulsifying a polyol having an average

equivalent weight of up to 400 (compound 2) in a polyol having an average

equivalent weight of 500 or more (compound 1) at a temperature of 20-100

⁰C and preferably of 20-70⁰C, adding a polyisocyanate to the emulsion,

optionally allowing the reaction mixture to mature for up to 2 hours,

wherein the entire process is conducted under high shear mixing

conditions, the temperature is kept below 15O⁰C, the temperature may be

allowed to become 12O⁰C or more for not more than 2 hours, the

temperature is kept at least 1O⁰C higher than the T₉ of the particulate

material formed at that stage, the used amount of compound 2 and

polyisocyanate together at the end of the polyisocyanate addition is 35-

80% by weight calculated on the weight of the polyol composition, and the number of isocyanate groups used per 100 isocyanate-reactive groups in

compound 2 is 70-100 and preferably 75-98.

[0014] In the context of the present application the following terms have the

following meaning :

1. The expression "polyurethane foam" as used herein generally refers to

cellular products as obtained by reacting polyisocyanates with

predominantly polyols, using foaming agents, and in particular includes

cellular products obtained with water as reactive foaming agent

(involving a reaction of water with isocyanate groups yielding urea

linkages and carbon dioxide and producing polyurea-urethane foams).

2. The term "average nominal hydroxyl functionality" is used herein to

indicate the number average functionality (number of hydroxyl groups

per molecule) of the polyol composition on the assumption that this is

the number average functionality (number of active hydrogen atoms

per molecule) of the initiator(s) used in their preparations although in

practice it will often be somewhat less because of some terminal

unsaturation. The term "equivalent weight" refers to the molecular

weight per isocyanate reactive hydrogen atom in the molecule.

3. The word "average" refers to number average unless indicated

otherwise.

[0015] The polyol having an average equivalent weight of 500 or more preferably

has an average equivalent weight of 1000-5000 and an average nominal hydroxy functionality of 2-6 (hereinafter referred to as compound 1) and

may be selected from polyols known in the art. More preferably the

polyols have an average equivalent weight of 1000-3000 and an average

nominal hydroxy functionality of 2-4.

[0016] Compound 1 may be selected from polyether polyols, polyester polyols,

polyesteramide polyols, polythioether polyols, polycarbonate polyols,

polyacetal polyols and polyolefin polyols.

[0017] Polyether polyols, which may be used, include products obtained by the

polymerization of a cyclic oxide, for example ethylene oxide, propylene

oxide, butylene oxide or tetrahydrofuran in the presence of polyfuctional

initiators. Suitable initiator compounds contain a plurality of active

hydrogen atoms and include water, butanediol, ethylene glycol, propylene

glycol, diethylene glycol, triethylene glycol, dipropylene glycol,

ethanolamine, diethanolamine, thethanolamine, toluene diamine, diethyl

toluene diamine, phenyl diamine, toluene diamine, diphenylmethane

diamine, ethylene diamine, cyclohexane diamine, cyclohexane dimethanol,

resorcinol, bisphenol A, glycerol, trimethylolpropane, 1 ,2,6-hexanetriol,

pentaerythritol, sorbitol and sucrose. Mixtures of initiators and/or mixtures

of cyclic oxides may be used as well.

[0018] The polyether polyols preferably are those based on propylene oxide (PO)

and/or ethylene oxide (EO). When they are based on both EO and PO the

amount of oxyethylene groups in the polyol may vary from 5-90% by weight, preferably 5-50% by weight and most preferably 5-25% by weight

calculated on the weight of the polyol. If polyols are used comprising

oxypropylene and oxyethylene groups, the polyols maybe block

copolymers, random copolymers and combinations thereof. A particularly

preferred polyether polyol is a polyoxypropylene polyoxyethylene polyol

having 5-25% by weight of oxyethylene units which are at the end of the

polymer chains (so-called EO-tipped EO/PO polyols).

[0019] Polyester polyols which may be used include hydroxyl-terminated reaction

products of polyhydric alcohols such as ethylene glycol, propylene glycol,

diethylene glycol, 1 ,4-butanediol, neopentylglycol, 1 ,6-hexanediol,

cyclohexane dimethanol, glycerol, trimethylolpropane, pentaerythritol or

polyether polyols or mixtures of such polyhydric alcohols, and

polycarboxylic acids, especially dicarboxylic acids or their ester-forming

derivatives, for example succinic, glutaric and adipic acids or their dimethyl

esters, sebacic acid, phthalic anhydride, tetrachlorophthalic anhydride or

dimethyl terephthalate or mixtures thereof. Polyesters obtained by the

polymerization of lactones for example caprolactone, in conjunction with a

polyol, or of hydroxy carboxylic acids such as hydroxy caproic acid, may

also be used.

[0020] Polyesteramide polyols may be obtained by the inclusion of aminoalcohols

such as ethanolamine in polyesterification mixtures. [0021] Polythioether polyols which may be used include products obtained by

condensing thiodiglycol either alone or with other glycols, alkylene oxides,

dicarboxylic acids, formaldehyde, amino-alcohols or aminocarboxylic

acids.

[0022] Polycarbonate polyols which may be used include products obtained by

reacting diols such as 1 ,3-propanediol, 1 ,4-butanediol, 1 ,6-hexanediol,

diethylene glycol or tetraethylene glycol with diaryl carbonates, for

example diphenyl carbonate, or with phosgene.

[0023] Polyacetal polyols which may be used include those prepared by reacting

glycols such as diethylene glycol, triethylene glycol or hexanediol with

formaldehyde. Suitable polyacetals may also be prepared by polymerizing

cyclic acetals.

[0024] Suitable polyolefin polyols include hydroxy-terminated butadiene homo-

and copolymers and suitable polysiloxane polyols include

polydimethylsiloxane diols and triols.

[0025] Preferably polyether polyols or mixtures of polyether polyols are used as

compound 1.

[0026] The polyol having an equivalent weight of up to 400 (hereinafter referred to

as 'compound 2') preferably has an equivalent weight of up to 200 and

may be selected from alkanolamines, low equivalent weight amine-initiated

polyether polyols and low equivalent weight hydroxyl-terminated compounds such as ethylene glycol, glycerine, glycol ethers,

pentaerythritol or mixtures thereof.

[0027] Suitable alkanolamines are di- and trialkanolamines, particularly those

wherein the alkanol groups have from 2 to 6, preferably 2 to 3 carbon

atoms.

[0028] The most preferred compound is triethanolamine.

[0029] The polyisocyanate used in making the PIPA polyol may be selected from

diphenylmethane diisocyanates (MDI) optionally comprising homologues

thereof having an isocyanate functionality of 3 or more (such diisocyanate

comprising such homologues are known as crude MDI or polymeric MDI or

mixtures of such crude or polymeric MDI with MDI) and modified variants

of such MDI optionally comprising homologues thereof having an

isocyanate functionality of 3 or more.

[0030] The diphenylmethane diisocyanate (MDI) used may be selected from 4,4'-

MDI, 2,4'-MDI, isomeric mixtures of 4,4'-MDI and 2,4'-MDI and less than

10% by weight of 2,2'-MDI, and modified variants thereof containing

carbodiimide, uretonimine, isocyanurate, urethane, allophanate, urea

and/or biuret groups. Preferred are 4,4'-MDI, isomeric mixtures of 4,4'-

MDI and 2,4'-MDI and less than 10% by weight of 2,2'MDI and

uretonimine and/or carbodiimide modified MDI having an NCO content of

at least 20% by weight and preferably at least 25% by weight and

urethane modified MDI obtained by reacting excess MDI and polyol having a molecular weight of at most 1000 and having an NCO content of at least

20% by weight and preferably at least 25% by weight.

[0031] Diphenylmethane diisocyanate comprising homologues having an

isoycanate functionality of 3 or more are so-called polymeric or crude MDI.

[0032] Polymeric or crude MDI are well known in the art. They are made by the

phosgenation of a mixture of polyamines obtained by the acid

condensation of aniline and formaldehyde.

[0033] The manufacture of both the polyamine mixtures and the polyisocyanate

mixtures is well known. The condensation of aniline with formaldehyde in

the presence of strong acids such as hydrochloric acid gives a reaction

product containing diaminodiphenylmethane together with polymethylene

polyphenylene polyamines of higher functionality, the precise composition

depending in known manner inter alia on the aniline/formaldehyde ratio.

The polyisocyanates are made by phosgenation of the polyamine mixtures

and the various proportions of diamines, triamines and higher polyamines

give rise to related proportions of diisocyanates, triisocyanates and higher

polyisocyanates. The relative proportions of diisocyanate, triisocyanate

and higher polyisoycanates in such crude or polymeric MDI compositions

determine the average functionality of the compositions, that is the

average number of isocyanate groups per molecule. By varying the

proportions of starting materials, the average functionality of the

polysiocyanate compositions can be varied from little more than 2 to 3 or even higher. In practice, however, the average isocyanate functionality

preferably ranges from 2.3-2.8. The NCO value of these polymeric or

crude MDI is at least 30% by weight. The polymeric or crude MDI contain

diphenylmethane diisocyanate, the remainder being polymethylene

polyphenylene polyisocyanates of functionality greater than two together

with by-products formed in the manufacture of such polyisocyanates by

phosgenation of polyamines. Further, modified variants of such crude or

polymeric MDI may be used as well comprising carbodiimide, uretonimine,

isocyanurate, urethane, allophanate, urea and/or biuret groups; especially

the aforementioned uretonimine and/or carbodiimide modified ones and

the urethane modified ones are preferred. Mixtures of polyisocyanates

may be used as well.

[0034] The amount of polyisocyanate used is such that the number of isocyanate

groups (NCO-groups) is 70-100% and preferably 75-98% of the hydroxy

groups (OH-groups) in the compound 2. The amount of polyisocyanate

and compound 2 together reflects the desired amount of particulate

material in compound 1 : if one wishes to prepare a polyol with 45% by

weight of particulate material then the amount of polyisocyanate and

compound 2 together is 45% by weight of the total composition (compound

1 + compound 2 + polyisocyanate).

[0035] The preparation of the polyol composition according to the present

invention starts with the emulsification of compound 2 in compound 1. This is done by mixing the 2 polyols under high shear mixing conditions at

a temperature of 20-100⁰C and preferably of 20-70⁰C.

To the emulsion so obtained the polyisocyanate is added and allowed to

react with compound 2. After addition of all polyisocyanate the mixture

may be allowed to mature for up to 2 hours which in fact is giving the

mixture more time to complete the reaction. This maturing step is

conducted while high shear mixing at least until the temperature of the

mixture is at least 1O⁰C under the T₉ of the particulate material and

preferably at least 2O⁰C under the T₉ of the particulate material and most

preferably at least 3O⁰C under the T₉ of the particulate material.

Subsequently mixing is discontinued and the polyol composition according

to the present invention is allowed to cool to ambient temperature.

Once the polyisocyanate addition has started the following measures need

to be taken:

- High shear mixing conditions are maintained throughout the

polyisocyanate addition.

- The reaction between the polyisocyanate and compound 2 is

exothermic. In order to avoid degradation the temperature may not

exceed 15O⁰C and the temperature may not exceed 12O⁰C for more

than 2 hours and preferably not for more than one hour. This may be

achieved by appropriate cooling which may be conducted in conventional ways of cooling reactors. These measures are also

maintained during the maturing step.

- An important finding of the present invention is that the temperature

needs to be kept above a certain minimum during the polyisocyanate

addition: at least 1O⁰C, preferably at least 2O⁰C and most preferably at

least 3O⁰C above the T₉ of the particulate material formed at that stage

of the process with the proviso that the maximum temperature

restrictions prevail. At the start of the polyisocyanate addition the

temperature should be above the melting point of all ingredients.

[0037] High shear mixing may be conducted in any known manner. A generally

known way is to use a mixer equipped with a rotor and a stator at a speed

which provides mixing and shearing.

[0038] The addition of the polyisocyanate may be conducted batchwise or

continuously and it may be fast or slow. Preferably the addition is as fast

as possible and the speed of addition in fact is limited by the efficiency of

the cooling equipment to keep the temperature below the maximum

values.

On the other hand, the addition preferably is not slower than the rate which

ensures a reaction temperature of at least 10⁰C above the T₉ of the

particles formed at that stage.

In order to simplify the process control one could determine for a certain

compound 1 , compound 2, polyisocyanate and loading (amount of particles desired) the T₉ of the particles after for example a conversion of

20, 40, 60 and 80%. From this T₉ curve a desirable reaction temperature

curve can be chosen keeping the temperature restrictions in mind.

By appropriate adjustment of the polyisocyanate addition speed and the

cooling capabilities such a temperature curve can then be followed.

Process control of this type does not require more than normal process

engineering skills and is daily routine for an average engineer. Based on

this description and the examples such engineers will be able easily to

conduct the process according to the present invention.

[0039] In order to further reduce the viscosity of a PIPA polyol composition, it is

preferred to use a small amount of water in the preparation of such polyol

composition. When used the amount of water is 0.1-5% by weight

calculated on the total amount of the polyol composition and preferably

0.1-2% by weight calculated on the same basis. The water may be added

at any stage but preferably it is added to compound 2 or the emulsion of

compound 1 and 2.

[0040] The polyol compositions of the present invention are useful in making

flexible polyurethane foams.

[0041] Examples

[0042] Ingredients used: Daltocel F-435 polyol (Daltocel is a trademark of

Huntsman International LLC; Daltocel-F-435 is a polyether polyol

obtainable from Huntsman Polyurethanes); triethanolamine (99% pure, TELA), Suprasec 2020 polyisocyanate (obtainable from Huntsman

Polyurethanes, Suprasec is a trademark of Huntsman International LLC)

and Arcol ™ 1342 ex Bayer (a polyether polyol having a nominal hydroxy

functionality of 3, and OH-value of 35mg KOH/g and an EO-tip content of

14% by weight).

[0043] Example 1

The example of WO 00/73364 was repeated, the polyol (PIPA polyol 1)

obtained had the following properties (see below Table 2).

[0044] Example 2

25Og of Arcol 1342 was blended with 76g of triethanolamine starting at

25⁰C. The mixture was then subjected to high shear mixing (all high shear

mixing in example 2 and 3 was conducted with a Silverson L4RT, standard

assembly, at 6000 rpm) for 5 minutes. At the end of the emulsification the

temperature was 45⁰C. Subsequently 174g of Suprasec 2020 was added

dropwise over a period of 15 minutes while maintaining high shear mixing

conditions (as above). The temperature rose gradually to 14O⁰C. Then

high shear mixing was continued for 15 minutes and after that the mixing

was stopped and the polyol composition was allowed to cool to ambient

conditions. At the end of the high shear mixing the temperature was 9O⁰C.

The polyol had the following properties; see below Table 2; PIPA polyol 2.

After addition of 25, 50, 75 and 100% of the MDI addition a sample was

taken and the temperature of the reactor, the viscosity of the sample and the Tg of the particulate material was determined. This was also done

after the maturing step. The results are in Table 1.

Table 1

MDI addition, % Reactor Viscosity at 25⁰C, T₉₁ ⁰C Δ(T-T_g),°C

Temperature, ⁰C mPa.s

25 50 10800 -21 71

50 77 13000 26 51

75 107 13200 70 37

100 140 21700 100 40

After maturing 90 19500* 101 -11

* The maturing step not only provides for a more complete reaction but

also prolonged high shear mixing leading to a slight viscosity

improvement.

[0045] Example 3

200Og of Arcol 1342 was blended with 525g of triethanolamine (TELA) and

2Og of water, followed by high shear mixing (as above) for 15 minutes

starting at 25⁰C. At the end of the emulsification the temperature was

45⁰C. 1455g of Suprasec 2020 was added dropwise over a period of 132

minutes while high shear mixing (the temperature rose to 14O⁰C at the end

of the addition). High shear mixing was continued for 90 minutes. At the

end of the high shear mixing the temperature was 9O⁰C. Then the mixing was discontinued and the polyol (PIPA polyol 3) was allowed to cool to

ambient conditions. The temperature profile was kept similar to example 2

but over a time period of 132 minutes.

[0046]

Table 2

1. The viscosity, T₉ and particle size distribution were measured as

described hereinbefore.

2. Moulded foams, made using PIPA-polyols 1 and 2, showed the

properties as in Table 3, also giving the other ingredients used (in

parts by weight) [0047]

Table 3

Suprasec 2185 is a polymeric MDI obtainable from Huntsman

Polyurethanes.

Claims

1. Polyol composition comprising particulate material in dispersed form in a polyol

having an equivalent weight of 500 or more and in an amount of 35-80% by

weight calculated on the total polyol composition, the composition having a

viscosity of 1500-25000 mPa.s at 25⁰C and the particulate material comprising

reaction products of a polyol having an equivalent weight of up to 400 and of

diphenylmethane diisocyanate optionally comprising homologues thereof

having an isocyanate functionality of 3 or more and/or modified variants of

such polyisocyanates, the particulate material having a glass transition

temperature of at least 75⁰C and at least 90% by volume of the particulate

material having a particle size of 10 μm or less.

2. Polyol composition according to claim 1 wherein the glass transition

temperature is at least 8O⁰C.

3. Polyol composition according to claims 1-2 wherein the amount of particulate

material is 40-60% by weight.

4. Polyol composition according to claims 1-3 wherein the polyol having an

equivalent weight of 500 or more is a polyether polyol having an equivalent

weight of 1000-5000 and an average nominal hydroxy functionality of 2-6.

5. Polyol composition according to claims 1-4 wherein the polyol having an

equivalent weight of up to 400 is an alkanolamine wherein the alkanol groups

have 2-6 carbon atoms.

6. Polyol composition according to claims 1-5 wherein at least 95% by volume of

the particles has a particle size of 10μm or less.

7. Process for preparing a polyol composition according to claims 1-6 by

emulsifying a polyol having an average equivalent weight of up to 400 in a

polyol having an average equivalent weight of 500 or more at a temperature of

20-100⁰C, adding a polyisocyanate to the emulsion, wherein the entire process

is conducted under high shear mixing conditions, the temperature is kept

below 15O⁰C, the temperature may be allowed to become 12O⁰C or more for

not more than 2 hours, the temperature is kept at least 1O⁰C higher than the T₉

of the particulate material formed at that stage, the used amount of the polyol

having an average equivalent weight of up to 400 and polyisocyanate together

at the end of the polyisocyanate addition is 35-80% by weight calculated on

the weight of the polyol composition, and the number of isocyanate groups

used per 100 isocyanate-reactive groups in the polyol having an average

equivalent weight of up to 400 is 70-100.

8. Process according to claim 7 wherein an amount of water is used which

ranges from 0.1 to 5% by weight calculated on the total amount of the polyol

composition.

9. Process according to claims 7-8 wherein the reaction mixture is allowed to

mature for up to 2 hours after the polyisocyanate addition.

10. Process according to claims 7-9 wherein the emulsification of the polyol having

an average equivalent weight of up to 400 in the polyol having an average

equivalent weight of 500 or more is conducted at a temperature of 20-70⁰C.