WO2002085964A2

WO2002085964A2 - Method for the preparation of a polyol based composition containing a stable polymeric filler

Info

Publication number: WO2002085964A2
Application number: PCT/EP2002/004510
Authority: WO
Inventors: Riccardo Po'; Luisa Fiocca
Original assignee: Dow Global Technologies Inc.
Priority date: 2001-04-24
Filing date: 2002-04-24
Publication date: 2002-10-31
Also published as: AU2002338403A1; ITMI20010861A0; WO2002085964A3; ITMI20010861A1

Abstract

A method for the preparation of a polyol based composition containing a stable polymeric filler comprising polymerizing at least one vinyl monomer, the vinyl monomer being mixed with a polyol component having a functionality of two or more and an average molecular weight of 500 or higher in the presence of a stabilizing agent obtained from the reaction of at least one polyether polyol end-capped with at least 1.5 amine groups and having an average molecular weight of 200 to 24000 with at least one anhydride comprising at least an unsaturated cyclic anhydride, the ratio of the amine groups of the at least one polyether polyol being such that at the end of the reaction with the at least one anhydride, the T/C ratio between the trans (T) double bonds and the cis (C) double bonds is at least 0.1.

Description

Method for the Preparation of a Polvol Based Composition Containing a Stable

Polymeric Filler

This invention concerns a method for the preparation of a polyol based composition containing a stable polymeric filler. Particularly, the invention concerns a method for the preparation of a polyol based composition containing a stable polymeric filler, the composition obtained in this manner and its use in the preparation of a polyurethane resin. The term "resin" as employed herein includes polyurethane foam.

Procedures for the preparation of polyol compositions containing as a dispersion or partially grafted on to the chain, solid polymeric particles prepared in situ by the polymerization of the corresponding monomers have been published previously in the scientific literature. US-A-4,357,430, for example, describes a method for the preparation of stable polymer/polyol compositions consisting of polymerising, in the presence of a free radical catalyst, an ethylenically unsaturated monomer or monomers dissolved or dispersed in a polyol mixture including a coupled polyol consisting of the reaction product of a polyol having a functionality in excess of 2 reacted with polyisocyanate in such proportion that the ratio of hydroxyl groups to isocyanate groups is greater than 1. In one embodiment, the coupled polyol is made in situ in the base polyol by addition thereto of the required amount of the polyisocyanate. The polymer/polyol compositions are convertible to polyurethane foams and elastomers.

US-A-6,013,731 discloses that polymer polyol stabilisers may be prepared through use of polyoxyalkylene polyols modified to contain induced ethylenic unsaturation, the polyoxyalkylene polyols prior to such modification having levels of intrinsic unsaturation of less than about 0.02 meq/g, a molecular weight greater than 3000 x F⁰³⁹ where F is the average functionality of the polyol, and a nominal functionality of 1 or more. Vinyl polymerisation is conducted in the presence of the stabiliser and a carrier polyol. The polymer polyols prepared according to the teachings of US-A-4,357,430 and US-A- 6,013,731 can be used to produce polyurethane foams.

The applicant has now found a method for the preparation of a polyol composition based on polyol containing a polymeric filler made using a stabiliser derived from an amine compound which provides a polyol composition having a high solids concentration. The composition suitably also exhibits high stability and an average particle size of the polymer particle such that it allows the composition to be filtered through a 40 micron filter.

The invention provides a method for the preparation of a polyol based composition containing a stable polymeric filler comprising polymerizing at least one vinyl monomer, the vinyl monomer being mixed with a polyol component having a functionality of two or more and an average molecular weight of 500 or higher in the presence of a stabilizing agent obtained from the reaction of at least one polyether polyol end-capped with at least 1.5 amine groups and having an average molecular weight of 200 to 24000, preferably 1500 to 8000 with at least one anhydride comprising at least an unsaturated cyclic anhydride, the ratio of the amine groups of the at least one polyether polyol being such that at the end of the reaction with the at least one anhydride, the T/C ratio between the trans (T) double bonds and the cis (C) double bonds is at least 0.1 , preferably at least 1.

Polyurethane foams made using a polyol composition according to the invention are hard as a result of their high solids content. It is desirable to employ a high level of solids content in the polyol used in the preparation of a polyurethane foam to reduce the isocyanate needed which reduces costs. It is also convenient and provides cost benefits to transport polyol with a high solids content and to dilute the polyol as necessary. Suitably, the polymeric filler comprises particles which are sufficiently large to be insoluble in the polyol being employed. Typically, the polymeric filler contain over 5000 monomeric units.

Suitably the polyol composition made by the method of the invention contains a filler having an average particle size which is sufficiently large to effect cell opening in polyurethane foam formed from the polymer polyol but is not so large as to have an adverse effect on foam properties. If the average particle size is higher than 40 microns, settling and caking may occur during storage and transport. A suitable range of average polymer particle size is 0.1 to 10 μm, preferably 1 to 10 μm.

The polyol component suitably has an average molecular weight of 1000 to 24000 and preferably from 1000 to 8000.

Desirably the T/C ratio is from 1 to 10.

According to the invention, the polymerization of the vinyl monomer is suitably carried out in a polyol component. The polyol component preferably comprises either ether or ester or a mixture of ether and ester. Suitably the polyol component is essentially either ester or ether. The polyol component may be selected from polyether polyols, polyether polyols containing ester groups, polyether polyols containing amine groups and polyester polyols. The preferred polyol component is one composed of one or more polyether polyols. Suitable polyether polyols may be obtained by condensing C₂ to CQ olefin oxides with a starter material, preferably having at least two active hydrogen atoms. Preferred olefin oxides include ethylene oxide, propylene oxide, butylene oxide and a mixture of two or more thereof.

Suitably the condensation is carried out with a starter material selected from a glycol, a triol, a tetrol, an amine including primary, secondary and tertiary amines, an alkanol amine, a polyamine or a mixture of two or more thereof. Suitable starter molecules include: water, amino alcohols particularly N-alkyl-diethanolamines for example N- methyl-diethanolamine, and diols, for example ethylene glycol, 1,3-propylene glycol, 1 ,4-butanediol and 1 ,6-hexanediol. Mixtures of starter molecules may also be used as desired.

Representative examples of polyether polyols suitable for use according to the invention include those based on ethylene oxide and/or propylene oxide and where the starter comprises a glycol, for example dipropylene glycol or an oligomer of propylene oxide with a molecular weight of less than 500; a triol, for example glycerin or trimethylol propane; a tetrol, for example pentaerythritol; an amine, for example ammonia; a diamine, for example ethylene diamine; an aromatic diamine, for example ortho-toluene diamine; an alkanol amine, for example triethanol amine; or a polyfu notional hydroxy alkane, for example xylitol, arabitol, sorbitol, sucrose and mannitol.

Examples of suitable starter materials having amine groups include those disclosed in WO 01/58976, especially the compounds described as component b2 employed in the process of the invention, and materials described in WO02/22702, especially those compounds described as initiator molecule b2a, b2b, b2c, b2d and b2e employed in the process of the invention described therein. Examples of other suitable starter materials include those described in EP-A-0539819.

Other suitable starter compounds for the base polyol include alkylene oxide polymerized di to tetrafunctional polyamines that contain at least one tertiary amine. These amine initiators include the following: aliphatic and aromatic, including N-mono, N,N- and N,N' dialkyl substituted diamines having 1 to 6 carbon atoms in the alkyl radical. Examples of suitable compounds include mono and dialkyl substituted ethylene diamine, diethylenetriamine, triethylenetetramine, 1 ,3-propylene amine, 1,3- or 1,4- butylenediamine, 1,2-, 1,3-, 1 ,4- 1,5-,1,6-hexamethylene diamine, phenylene diamine, 2,4 or 2,6- toluene diamine, 4,4'- or 2,4'-and 2,2'-diaminodiphenylmethane; alkanolamines including N-methyl and N-ethyl diethanol amine, N-methyl- and N- ethyldiethanolamine and triethanolamine, N-methyl and N-ethyl diethanolamine and triethanolamine, N-methyl and N-ethyl dipropanolamine, N-methyl- and N- ethyldipropanolamine and tripropanolamine, N-methyl and N-ethyl dipropanolamine and tripropanolamine.

Examples of especially preferred starter materials for polyether polyols include N-methyl diethanolamine, N-methyldipropanolamine, N-(2-hydroxyethyl)-N-methyl-1 ,3- propanediamine, N-(2-hydroxyethyl)-N-methyl-1 ,3-ethanediamine, 3,3'-diamino-N- methyldipropylamine, 3,3'-diamino-N-ethyldipropylamine, 2,2'-diamino-N- methyldiethylamine.

Any vinyl monomer capable of dissolving in the polyol component can be used in the method of the invention. Illustrative examples include acrylic acids, methacrylic acid, methylacrylate, methylmethacrylate, ethylacrylate, acrylomethacrylamide, vinyl chloride, vinylidine chloride, acrylonitrile, methacrylonitrile, styrene, brominated styrenes, butadiene, isoprene, isobutene and their mixtures. Additional examples of monomers are cited in F.E. Bailey, J.V. Koleske "Alkylene Oxides and Their Polymers" Marcel Dekker. Preferred monomers include acrylonitrile and styrene used alone or in combination. Where acrylonitrile and styrene are used in combination, the preferred styrene/acrylonitrile weight ratio is from 100:0 (de minimis level of acrylonitrile) to 40:60. More preferably, the styrene/acrylonitrile weight ratio is from 80:20 to 40:60. The combination of styrene/acrylonitrile advantageously reduces problems due to discolouration.

These monomers may be polymerized by conventional methods. In particular, the monomer may be combined with the polyol component in an amount from 20 to 65% by weight based on the total, more preferably 20 to 60 % by weight based on the total. Suitably, the monomer may be added to the polyol component. The monomers may be reacted at a temperature of from 80 to 150°C optionally in the presence of one or more of a radical initiator, a molecular weight regulator and a chain transfer agent.

The radical polymerization initiator may be combined with the polyol in an amount generally of from 0.05 to 3% by weight, based on the vinyl monomer and can be selected from peroxides, persulfates, perborates, percarbonates and azo derivatives. Examples include dibenzyl peroxide, lauryl peroxide, di-tert-butyl peroxide, t-butyl peroxide, 2-ethylhexanoate, t-amyl peroxide, 2-ethylhexanoate, dicumyl peroxide, benzyl hydroperoxide, t-butyl hydroperoxide, cumyl hydroperoxide, 2,2-azobis (isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile).

The chain transfer agent may be added to the polyol component in an amount generally of from 0.1 to 2% by weight and can be selected from mercaptans such as dodecyl mercaptan, ethyl mercaptan, propyl mercaptan, butyl mercaptan, hexyl mercaptan, oxtyl mercaptan, decyl mercaptan, octadecyl mercaptan, 2-mercaptoethanol.

The stabilizing agent is combined with the vinyl monomer, preferably in an amount of from 0.5 to 20% by weight, preferably 2 to 10% based on the total. The stabilizing agent is prepared by the reaction of an amine capped polyol with an unsaturated cyclic anhydride or with a mixture containing an unsaturated and a saturated cyclic anhydride. Where a mixture of unsaturated and saturated cyclic anhydrides is used, a molar ratio of unsaturated to saturated anhydride greater than or equal to 0.5 is preferably used, more preferably a molar ratio between 1 and 10.

The amine capped polyether polyol is preferably selected from a polyoxyethylene glycol and a polyoxypropyleneglycol with at least 1.5 amine groups. The amine capped polyether preferably contains at least one primary terminal amine group for example 1 to 3. Compounds having 1.5 to 8 terminal amine groups are especially preferred.

Suitable aminated polyols include those of formula:

R¹R²'N[EO]_a[PO]_b[AO]_c[CH₂CHR]NR³R⁴

having a molecular weight of 500 to 10000, preferably 1000 to 5000 in which R¹ to R⁴ are independently selected from H, alkyl groups, preferably having 1 to 10 carbon atoms, and optionally containing alkylene oxide units, EO denotes an ethylene oxide monomeric unit, PO denotes a propylene oxide monomeric unit and AO denotes an alkylene oxide other than EO and PO and a, b and c are, independently integers from 0 to 100 provided that not all of a, b and c are 0. In a preferred embodiment, a and c are 0, R¹ to R⁴ are each hydrogen and b is of such value as to provide a molecular weight of 1000 to 5000.

Suitable polyols include those which are commercially available under the name Jeffamine™ from Huntsman Polyurethanes. Suitable amine-capped polyols may be industrially prepared by conventional methods described, for example, in the "Saunders and Frisch - Polyurethanes, Chemistry and Technology" Interscience, New York, 1964 or in the previously cited Bailey and Koleske text.

Examples of suitable unsaturated anhydrides include maleic anhydride, citraconic anhydride and 2,3-dimethylmaleic anhydride.

The reaction is preferably conducted operating in batch at a temperature of from 60 to 180°C, preferably of from 100 to150°C, and more preferably of 115 to 135 °C, maintaining the reagents in contact over a period from 1 hour to 8 hours. The molar ratio between the amine groups and the anhydride is preferably between 5 and 1.

At the end of the reaction, the free carboxylic acid groups may be converted into hydroxides by a reaction with epoxide, for example ethylene oxide, propylene oxide, butylene oxide, and hexene oxide, epichlorohydrin or with an alkylene carbonate, for example ethylene carbonate and propylene carbonate. The reaction may be conducted in batch under basic catalysis conditions and at a temperature of from 60 to 180°C.

Unreacted monomer may be removed after polymerisation or during the reaction, for example in a continuous process. Removal is preferably carried out by a known method, for example stripping with an inert gas and evaporation under vacuum at 50 to 180°C, more preferably 80 to 140 °C. The vacuum pressure is suitably less than 10 mbar. The final composition obtained in this manner typically has a solid filler content comprised between 20% to 60% by weight, an average particle size of the solids (measured by "Light Scattering" according to the Fraunhofer optical model on the Beckman Coulter LS230 instrument) of less than 5 microns and complete filterability through a filter with a 40 micron mesh. After being kept in a closed container for 28 days, there is typically no sediment visible.

The polyol based composition containing the stable polymeric filler of the invention may be used in the preparation of a polyurethane resin and particularly in the preparation of rigid or flexible expanded polyurethane resins together with conventional isocyanate reagents.

According to the invention, any organic isocyanate that is at least bifunctional may be used with the polyol composition. Low to medium molecular weight diisocyanates with a general formula (I):

OCN - R - NCO (I)

where R represents a linear or branched alkyl radical or a mixture of linear and branched alkyl radicals Ci to Cι₂, herein after referred to as (iso)alkyl radical Ci to C₁₂, cycloalkyl C₅ to C₁₅ or aromatic Cβ to Cι₈, all optionally substituted with alkyl radicals Ci to C₄ are particularly suitable. Suitable examples of these products are hexamethylene diisocyanate meta- and/or paraphenylene diisocyanate, 2,4-toluene diisocyanate (TDI), either alone or with the isomer 2,6-toluene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1-isocyanato-3-isocyanatomethyl-3,3,5-trimethyl cyclohexane, and 4,4'- diphenylmethane diisocyanate (MDI) optionally mixed with the 2,4' isomer.

Suitably, a high molecular weight polyisocyanate in various degrees of condensation may be used. Suitable polyisocyanates may be obtained from the phosgenation of aniline formaldehyde condensates. These products comprise mixtures of polymethylenepolyphenyl polyisocyanates with a general formula (II):

where Φ represents a phenyl group and n is a whole number greater than or equal to 1.

The preferred medium to high molecular weight diisocyanates and polyisocyanates of the invention include polymethylenepolyphenyl polyisocyanates with an average functionality of from 2.6 to 2.8. These products are commercially available under various designations such as "Tedimon 31 ™" (EniChem S.pA), "Suprasec DNR™" (Hunstman Polyurethanes) or "Desmodur 44 V20™" (Bayer).

Additional examples of polyisocyanates are isocyanic prepolymers obtained by reacting an excess in equivalents of one or more isocyanates of general formula (I) or (II) with one or more of a polyether polyol and a polyester. Optionally, the polyether polyol or polyester contains one or more of mixed ether or ester groups or amine groups. The prepolymer preferably has a functionality of from 2 to 8 and an NCO equivalent weight (molar weight per NCO group) from approximately 50 to 6000, more preferably from 50 to 2000.

In the preparation of a polyurethane resin, particularly of an expanded polyurethane resin, in addition to the conventional reagents, the reaction mixture may also comprise one or more other additives that are commonly used for preparation of a polyurethane resin, for example amine catalysts such as triethylenediamine, and/or metal complexes, for example tin octanoate, cell regulators, thermo-oxidation stability agents and pigments. Details concerning the polymerization of polyurethanes are described in the text "Saunders & Frisch - Polyurethanes, Chemistry and Technology" Interscience, New York, 1964.

When making expanded polyurethanes, the blowing agent preferably comprises water used alone or with one or more secondary blowing agents. In the preparation of expanded polyurethanes, water has an important function since it is responsible for the formation of urea bonds associated to the formation of CO₂ that triggers the expansion/blowing process of the polyurethane resin resulting in the expanded flexible foam. The most commonly used amount of water is from 0.1 to 6 parts by weight based on 100 parts of the polyol composition, more preferably from 3 to 6 parts by weight.

According to conventional technology, for the expansion of the polyurethane resin, the preferred primary blowing agent is CO₂ produced in situ by the chemical reaction between the water and the NCO groups of the polyisocyanate. The method for introducing the primary blowing agent into the polymerization mixture should not be taken as limiting since other gases or other techniques can be used, such as for example, air bubbling, nitrogen or other inert gases introduced by external injection that do allow us to obtain similar products.

However, in the preparation of a low density expanded polyurethane, for example, a polyurethane with a density less than or equal to 25 kg/m³, the expanding or blowing function of the water alone can be sufficient to achieve those density values without the inconvenience (scorching) incurred from the exotherm of the reaction between the water and the isocyanate groups. In this case, the expanding action of the water can be supported by physical expanding agents selected from hydrofluoro alkanes, liquid CO₂, hydrocarbons, for example n-pentane, i-pentane, and cyclopentane, dimethyl carbonate and their mixtures.

In order to better understand the invention and how the invention may be implemented, we shall include several illustrative but not limiting examples.

Example 1 - Preparation of Stabilising Agent

Into a two necked flask equipped with magnetic agitation and a stopcock valve for introducing nitrogen connected to a bubbler are introduced under a nitrogen flow, 30.2 g (7.5 mmoles) of polypropylene glycol)bis(2-aminopropylether) with a molecular weight of 4000 and 1.47 g (15 mmoles) of maleic anhydride. After shutting off the nitrogen flow, the reaction mixture is heated to 130°C for 24 hours.

The final product has a T/C ratio of 2. In each case, the T/C ratio is determined by NMR.

Example 2 - Preparation of Stablisinα Agent

Into a 100 ml AISI 316 steel autoclave we introduced 50 g of the reaction mixture of Example 1 , containing 0.22 meq/g of carboxylic groups. Then we introduced 0.62 g (11 mmoles) of KOH and the reactor was purged with nitrogen until the pressure reached 2 atm. Then we introduced 5 g (115 mmoles) of ethylene oxide and the reaction mixture is heated gradually until reaching 125°C over 2 hours.

The final product has a T/C ratio of 2.5.

Example 3 - Preparation of Stabilising Agent

Into a two necked flask equipped with magnetic agitation and a stopcock to allow the introduction of nitrogen connected to a bubbler we introduced under an nitrogen flow 30 g (7.5 mmoles) of poly(propyleneglycol)bis(2-aminopropylether) with a molecular weight of 4000 and 1.49 g (15 mmoles) of maleic anhydride and 0.009 g (0.5% by weight) Irganox 1010™ antioxidant (Ciba Geigy). After shutting off the nitrogen flow, the reaction mixture is heated to 180°C over 4 hours.

The final product has a T/C ratio of 2.8.

Example 4 - Preparation of Stabilising Agent

Into a two necked flask under magnetic agitation and equipped with a stopcock for the introduction of nitrogen connected to a bubbler are introduced under a nitrogen flow 30.2 g (7.5 mmoles) of poly(propyleneglycol)bis(2-aminopropylether) with a molecular weight of 4000 and 1.47 g (15 mmoles) of maleic anhydride. After shutting off the nitrogen flow, the reaction mix is heated to 130°C over 4 hours. The final product has a T/C ratio of 0.2.

Example 5 - Preparation of Polvol Based Composition

Into a pressure resistant glass reactor equipped with manometer and magnetic agitation we introduced: • 10.41 g (52.5% by weight) of a trifunctional polyether polyol with an average molecular weight MW of 3500 (Glendion FG 3504™ from EniChem), 1.42 g (7% by weight) of the stabilizing agent formed in example 1 , 5.7 g (28% by weight) of styrene, 2.39 g (12% by weight) acrylonitrile, • 0.06 g dodecanethiol,

0.062 g benzoylperoxide.

The reaction is closed and the mixture is heated to 110°C for 360 minutes. The reaction mixture is allowed to cool and the unreacted volatile products are removed by maintaining at 50°C under vacuum for 90 minutes and then under vacuum at 100°C for 360 additional minutes. The final product is a white viscous dispersion.

Example 6 - Preparation of Polvol Based Composition

We operate as described in Example 5 using the following formulation:

• 10.51 g (52.5% by weight) of a trifunctional polyether polyol (Glendion FG 3504™ from EniChem),

• 1.42 g (7% by weight) of the stabilizing agent formed in Example 1 , • 6.4 g (32% by weight) styrene,

• 1.6 g (8% by weight) acrylonitrile, • 0.05 g of dodecanethiol,

• 0.061 g of benzoylperoxide.

Example 7 - Preparation of Polvol Based Composition

We operate as described in Example 5 using the following formulation:

• 10.96 g (54.5% by weight) of a trifunctional polyether polyol (Glendion FG 3504™ from EniChem), • 1.03 g (5% by weight) of the stabilizing agent formed in Example 1 ,

• 5.6 g (28% by weight) styrene,

• 2.41 g (12% by weight) acrylonitrile,

• 0.06 g of dodecanethiol,

• 0.062 g of benzoylperoxide.

Example 8 - Preparation of Polvol Based Composition

We operate as described in Example 5 using the following formulation:

• 11.33 g (56.5% by weight) of a trifunctional polyether polyol (Glendion FG 3504™ from EniChem),

0.6 g (3% by weight) of the stabilizing agent formed in Example 1,

5.6 g (28% by weight) styrene,

2.4 g (12% by weight) acrylonitrile, • 0.05 g of dodecanethiol,

0.062 g of benzoylperoxide.

Example 9 - Preparation of Polvol Based Composition

We operate as described in Example 5 using the following formulation: 8.5 g (42.5% by weight) of a trifunctional polyether polyol (Glendion FG 3504™ from

EniChem),

1.4 g (7% by weight) of the stabilizing agent formed in Example 1 ,

7.08 g (35% by weight) styrene,

2.92 g (15% by weight) acrylonitrile,

0.05 g of dodecanethiol,

0.061 g of benzoylperoxide.

Example 10 - Preparation of Polvol Based Composition

We operate as described in Example 5 using the following formulation:

• 8.9 g (44.5% by weight) of a trifunctional polyether polyol (Glendion FG 3504™ from EniChem), • 1.02 g (5% by weight) of the stabilizing agent formed in Example 1 ,

• 7.1 g (35% by weight) styrene,

• 2.92 g (15% by weight) acrylonitrile,

• 0.06 g of dodecanethiol,

• 0.066 g of benzoylperoxide.

Example 11 - Preparation of Polvol Based Composition

We operate as described in Example 5 using the following formulation:

• 6.57 g (32.5% by weight) of a trifunctional polyether polyol (Glendion FG 3504™ from EniChem),

• 1.42 g (7% by weight) of the stabilizing agent formed in Example 1 ,

• 8.44 g (42% by weight) styrene,

• 3.56 g (18% by weight) acrylonitrile, • 0.06 g of dodecanethiol, • 0.062 g of benzoylperoxide.

Example 12 - Preparation of Polyol Based Composition

We operate as described in Example 5 using the following formulation:

• 1.46 g (7% by weight) of the stabilizing agent formed in Example 1 , • 8.02 g (40% by weight) styrene,

• 0.08 g of dodecanethiol,

• 0.062 g of benzoylperoxide.

Example 13 - Preparation of Polvol Based Composition

Into a pressure resistant glass reactor equipped with a manometer and magnetic agitation, introduce in order:

• 10.47 g (52.5% by weight) of a trifunctional polyether polyol (Glendion FG 3504™ from EniChem),

• 1.42 g (7% by weight) of the stabilizing agent formed in Example 1 ,

• 8.0 g (40% by weight) styrene,

• 0.05 g of dodecanethiol,

• 0.095 g of benzoylperoxide.

After loading the polyol, stabilizer, styrene, dodecanethiol and 0.47 g of benzoylperoxide, the reactor is closed and the mixture is heated to 25°C for 300 minutes. Subsequently the reaction mix is allowed to cool and after releasing the residual pressure we add into the reactor 0.048 g of benzoylperoxide under a nitrogen flow and is heated to 125°C for another 300 minutes. The unreacted volatile products are removed under vacuum initially at 50°C for 90 minutes and again under vacuum at 100°C for another 360 minutes.

Exam^ple 14 - Preparation of Polvol Based Composition

We operate as described in Example 5 using the following formulation:

10.52 g (52.5% by weight) of a trifunctional polyether polyol (Glendion FG 3504™ from EniChem),

1.41 g (7% by weight) of the stabilizing agent formed in Example 3,

5.61 g (28% by weight) styrene,

2.45 g (12% by weight) acrylonitrile,

0.05 g of dodecanethiol,

0.066 g of benzoylperoxide.

Example 15 - Preparation of Polvol Based Composition

We operate as described in Example 5 using the following formulation:

• 10.52 g (52.5% by weight) of a trifunctional polyether polyol (Glendion FG 3504™ from EniChem),

1.41 g (7% by weight) of the stabilizing agent formed in Example 4, 5.61 g (28% by weight) styrene,

2.42 g (12% by weight) acrylonitrile, • 0.05 g of dodecanethiol,

0.064 g of benzoylperoxide.

Comparative Example A

In a glass reactor that is resistant to pressure provided with a manometer and magnetic agitation introduce in order: 9.0 g (44.5% by weight) of a trifunctional polyether polyol (Glendion FG 3504™ from

EniChem),

0.964 g (0.24 mmoles) of poly(propyleneglycol)bis(2-aminopropyl ether)

0.038 g (0.48 mmoles) of acrylic acid

7.07 g (35% by weight) styrene,

2.91 g (15% by weight) acrylonitrile,

0.07 g of dodecanethiol,

0.061 g of benzoylperoxide.

The reactor is closed and the mixture is heated to 110°C for 360 minutes. The reaction mix is allowed to cool and the unreacted volatile products are removed initially under vacuum for 90 minutes at 50°C and then under vacuum at 100°C for another 360 minutes. The final product is a yellow viscous dispersion.

Comparative Example B

Into a flask are introduced in order:

• 0.041 g (0.73 mmoles) of KOH tablets, • 0.1 g of polyether polyol (Glendion FG 3504™),

• 0.041 g of distilled water.

The solution is placed under magnetic agitation until the KOH is completely dissolved and then add 0.2 g of polyol obtaining an emulsion at the end.

Into a pressure resistant glass reactor equipped with a manometer and provided with magnetic agitation we introduce in order 107 g of Glendion FG 3504™ and the emulsion described above. The reaction mixture is heated to an internal temperature of 105°C and by means of a capillary tube we bubble nitrogen for 4 hours. Then the reaction mixture is allowed to cool, then to the mixture under nitrogen is added 1.79 g (18.2 mmoles) of maleic anhydride. The reaction is heated to 120°C for 8 hours. The final product has a T/C ratio of 0.

Comparative Example C

Into a pressure resistant glass reactor, equipped with a manometer and magnetic agitation is introduced in order:

10.4 g (52.5% by weight) of trifunctional polyether polyol (Glendion FG 3504™ from

EniChem),

1.4 g (7% by eight) of stabilizer from Comparative Example B,

5.7 g (28% by weight) of styrene,

2.4 g (12% by weight) of acrylonitrile,

0.05 g of dodecanethiol,

0.061 g of benzoylperoxide.

The reactor is closed and the mixture is heated to 110°C for 360 minutes. The reaction mixture is allowed to cool and the unreacted volatile product is removed under vacuum at 50°C for 90 minutes and then under vacuum at 100°C for another 360 minutes. The final product is a viscous yellow dispersion.

The following table shows the properties of the polyols containing the polymeric filler according to what is described in the previous examples. Table 1

The results illustrate that the present invention enables a high level of solids to be employed.

Example 16

In a one liter reactor equipped with an internal agitator and vacuum and nitrogen feed lines is charged 40 g of the stabilizing agent of Example 1 and 254 g of the trifunctional polyether polyol (Glendion FG 3504™ EniChem). The following is charged into the reactor at 110°C over 2 hours: • 235.2 g of styrene,

• 100.8 g of acrylonitrile,

• 2.1 g of dodecanethiol, • 0.99 g of benzoylperoxide,

• 169.6 g of Glendion FG 3504™ .

At the end of the reaction the residual monomers are removed by stripping under vacuum for 90 minutes. The product has a viscosity of 24,000 mPa second at 25°C.

Example 17

In a one liter reactor equipped with an internal agitator and vacuum and nitrogen feed lines are charged 16 g of the stabilizing agent of Example 1 and 320 g of the trifunctional polyether polyol (Glendion FG 3504™ EniChem). The following is charged into the reactor at 110°C over 2 hours:

• 168 g of styrene,

• 72 g of acrylonitrile, • 1.5 g of dodecanethiol,

• 0.71 go of benzoylperoxide,

• 224 g of Tercarol 909SAO™ (MW = 3600, functionality = 3).

At the end of the reaction the residual monomers are removed by stripping under vacuum for 90 minutes. The product has a viscosity of 2260 mPa second at 25°C.

Claims

1. A method for the preparation of a polyol based composition containing a stable polymeric filler comprising polymerizing at least one vinyl monomer, the vinyl monomer being mixed with a polyol component having a functionality of two or more and an average molecular weight of 500 or higher in the presence of a stabilizing agent obtained from the reaction of at least one polyether polyol end-capped with at least 1.5 amine groups and having an average molecular weight of 200 to 24000 with at least one anhydride comprising at least an unsaturated cyclic anhydride, the ratio of the amine groups of the at least one polyether polyol being such that at the end of the reaction with the at least one anhydride, the T/C ratio between the trans (T) double bonds and the cis (C) double bonds is at least 0.1.

2. A method according to claim 1 , further comprising the step of removing the unreacted monomer from the reaction mixture.

3. A method according to claim 1 or claim 2 in which the average polymer particle size is 1 to 10 μm.

4. A method according to any one of the preceding claims in which the polyol component has an average molecular weight of 1000 to 8000.

5. A method according to any one of the preceding claims in which the T/C ratio is from 1 to 10.

6. A method according to any one of the preceding claims in which the polyol component comprises an ether or ester type polyol selected from polyether polyols, polyether polyols containing ester groups, polyether polyols containing amine groups and polyester polyols, or mixtures of two or more thereof.

24

7. A method according to claim 6, where the polyol component is composed of one or more polyether polyols obtained by the condensation of at least one C₂to C₆ olefin oxide with a starter compound having at least two active H atoms.

8. A method according to claim 7, where the olefin oxide is selected from ethylene oxide, propylene oxide, butylene oxide and a mixture of two or more thereof.

9. A method according to any one of claims 7 and 8, wherein the polyether polyol is based on ethylene oxide and/or propylene oxide and the starter is selected from a glycol, a triol, a tetrol, a diamine, a tertiary amine, an aromatic amine, an alkanol amine, and a polyfu notional hydroxy alkane.

10. A method according to any one of the preceding claims, wherein the vinyl monomer is selected from acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethylacrylate, acrylamide, methacrylamide, vinylchloride, vinylidine chloride, acrylonitrile, methacylonitrile, styrene, brominated sytrene, butadiene, isoprene, isobutene and a mixture of two or more thereof.

11. A method according to claim 10, wherein the vinyl monomer is selected from acrylonitrile, styrene and a mixture of acrylonitrile and styrene.

12. A method according to claim 11 , wherein the vinyl monomer comprises a mixture of styrene and acrylonitrile in a styrene/acrylonitrile ratio from 100:0 (de minimis level) to 40:60.

13. A method according to any one of the preceding claims, wherein the vinyl monomer is added to the polyol component in an amount of 20 to 65% by weight based on the total.

14. A method according to any one of the preceding claims, wherein the stabilizing agent is added in an amount of 0.5 to 20% by weight of the total.

15. A method according to any one of the preceding claims, wherein the stabilizing agent is prepared from at least one amine capped polyether polyol, selected from a polyethylene polyol and a polyoxypropylene polyol containing at least 1.5 amine groups.

16. A method according to any one of the preceding claims, wherein the stabilizing agent is prepared from at least one amine capped polyether polyol of formula:

R¹R²'N[EO]_a[PO]_b[AO]_c[CH₂CHR]NR³R⁴

having a molecular weight of 500 to 10000 in which R¹ to R⁴ are independently selected from H and an alkyl group optionally containing alkylene oxide units, EO denotes an ethylene oxide monomeric unit, PO denotes a propylene oxide monomeric unit and AO denotes an alkylene oxide other than EO and PO and a, b and c are, independently integers from 0 to 100 provided that not all of a, b and c are 0.

17. A method according to claim, wherein a and c are 0, R¹ to R⁴ are each hydrogen and b is of such value as to provide a molecular weight of 1000 to 5000.

18. A method according to any one of the preceding claims, wherein the at least one anhydride comprises an unsaturated and a saturated cyclic anhydride with an unsatu rated/saturated anhydride molar ratio greater than or equal to 0.5.

19. A method according to any one of the preceding claims, wherein the stabilizing agent is obtained at a temperature from 60 to 180°C maintaining the at least one polyether polyol and at least one anhydride in contact for 1 to 8 hours.

20. A method according to any one of the preceding claims wherein the stabilizing agent is prepared with a molar ratio between the amine groups and the anhydride of 12 to 1.

21. A method according to any one of the preceding claims, wherein at the end of the reaction to produce the stabilizing agent, any free carboxylic groups are converted to hydroxides by means of a reaction with an epoxide or with an alkyl carbonate.

22. A method according to claim 21 , wherein the reaction is conducted in batch with a basic catalyst and at a temperature from 60 to 180°C.

23. A method according to any one of the preceding claims, wherein the unreacted vinyl monomers are removed by stripping with an inert gas or by evaporation under vacuum at 50 to 180°C.

24. A polyol based composition containing a polymeric filler obtainable by a method as defined in any one of the preceding claims.

25. A polyol based composition according to claim 24, wherein the polymeric filler is from 20% to 60% by weight of the composition.

26. A polyol based composition according to any one of claims 24 or 25, wherein the polymeric filler has an average particle size of less than 5 microns.

27. Use of a polyol based composition containing a polymeric filler as defined in any one of claims 24 to 26 in combination with an isocyanate in the preparation of an expanded rigid or flexible polyurethane resin.

28. Use according to claim 27, wherein the isocyanates are at least bifunctional and are selected from among low or medium molecular weight diisocyanates of general formula (I):

OCN - R - NCO (I) where R represents an (iso)alkyl radical Ci - Cι₂, a cycloalkyl radical C₅ - C₁₅ or aromatic radical Cβ - Cι₈, optionally substituted with alkyl radicals Ci - C₄ and those isocyanates of the general formula (ll)obtainable by the phosgenation of aniline- formaldehyde condensates:

29. Use according to any one of claims 27 or 28, wherein the isocyanates are selected from among the isocyanate prepolymers obtained by reacting an excess in equivalents of one or more isocyanates of general formula (I) or (II) with at least one polyether polyol and/or polyester polyol, optionally containing mixed ether or ester groups and/or amine groups with a functionality of 2 to 8 and an equivalent weight of 50 to 2000.

30. Use according to any one of claims 27 to 29, wherein the polyol composition comprises water as a blowing agent used alone or in combination with a secondary blowing agent.

31. Use according to claim 30, wherein the polyol composition contains water in an amount of 0.1 to 6 parts by weight with respect to 100 parts of the polyol component.