WO1998058979A1

WO1998058979A1 - Polyurea polyurethane elastomers with high temperature resistance and/or flame-retardant and/or excellent resistance to hydrolysis

Info

Publication number: WO1998058979A1
Application number: PCT/FR1998/001104
Authority: WO
Inventors: Roland Ganga; Claude Vachon
Original assignee: Roland Ganga; Claude Vachon
Priority date: 1997-06-20
Filing date: 1998-06-02
Publication date: 1998-12-30
Also published as: FR2764893A1; AU8024698A

Abstract

The invention concerns polyurea-polyurethanes, flame-retarded or not, with high resistance to continuous temperature above 150 °C and methods for producing them. The invention also concerns methods for preparing polyurea-polyurethane elastomers with remarkable properties of resistance to temperatures from -60 °C to +180 °C and a UL 94 V 0 fire rating and/or excellent resistance to hydrolysis.

Description

VERY HIGH TEMPERATURE POLYURETHANE POLYURETHANE ELASTOMERS AND / OR FLAME RETARDANTS AND / OR EXCELLENT HYDROLYSIS RESISTANCE

The present invention relates to a process for the preparation of new polyurethane-polyurea elastomers having higher heat resistance than elastomers of the same category, high resilience, low hysteresis, high mechanical properties and remarkable fire resistance (VO fire classification according to ISO 1210) and or excellent resistance to hydrolysis. All of these qualities give these elastomers a behavior which is particularly suitable for withstanding the constraints of rapid compression-decompression cycles due to the absence of thermoplastic creep and the maximum return of the energy absorbed.

These qualities are particularly desirable for many applications concerning technical parts subject to high constraints such as: conveyor belts, coatings for rollers for the steel industry, glassware, printing, coupling sleeves, anti-humidity electrical insulation for connectors mainly in the hot parts under the hoods of vehicles. protection of printed circuits and various computer components, vehicle wheel treads, anti-corrosion coatings for tubes and pipes carrying fluids at temperatures and / or under pressure (HP / HT pipes) microwave absorbents

Up to now, a large variety of polyurethane elastomers or heteropolymers with urethane and other functional groups (urea for example) has been produced with various processing methods and a very wide range of formulations.

However, all these elastomers have a relatively low heat resistance not exceeding 130 ° C. in continuous operation mainly when large elastic properties are sought (As described in US Patent 3,428,610 A of February 1969 KLEBERT WOLFANG To improve resistance to heat, the use of reagents having a functionality greater than 2 (isocyanates in particular) has been recommended, so as to obtain branched or three-dimensional molecular chains. However, as the three-dimensional character increases, the elastomeric properties degrade and the duromers are progressively obtained with loss of elongation and elastic behavior.

The object of the invention is to provide new polyurethane-polyurea elastomers which exhibit both excellent resistance to heat and / or to flame and / or hydrolysis, while retaining good elastomeric properties, as well as 'a process for their preparation.

The invention relates to new polyurethane-polyurea elastomers comprising flexible segments derived from at least one diol with terminal OH groups, θ urethane segments resulting from the reaction between the terminal OH groups of the diol and at least one diisocyanate, and segments ureas resulting from the subsequent reaction of at least one diamine with NCO end groups present on the urethane segments before their reaction with the diamine and with a possible excess of diisocyanate, characterized in that:

<151 °) The flexible segments are derived from a diol chosen from polyether diols. Polyolefin diols with terminal OH group and their combinations: diols having a molecular weight of 650 to 18,000

2) The urethane segments are rigid and result from the reaction between the terminal OH groups of said diol and at least one diisocyanate reagent comprising a

Z0 aromatic diisocyanate comprising a single benzenic or naphthalene ring and optionally a cycloaliphatic diisocyanate or of a mixture of diisocyanates 3 °) The urea segments are rigid and result from the reaction between a diamine reagent comprising an aromatic diamine comprising a single benzenic, naphthalene ring or anthracene and optionally a cycloaliphatic diamine and the terminal NCO groups present on the urethane segments before their reaction with the diamine and a cycloaliphatic diisocyanate 4 °) At least part of the diisocyanate and / or diamine reagents has its two functional groups in the ortho or meta The invention also relates to the process for the preparation of these new polyurethane-polyurea elastomers which comprises reacting at least one diol with terminal OH groups and an excess of at least one diisocyanate to form a polyurethane prepolymer having NCO groups then the reaction of the NCO groups of the prepolymer thus obtained with at least one diamine to form a polyurethane-polyurea elastomer, characterized in that:

1 °) The diol is chosen from polyether diols and polyolefin diols having a molecular weight of 650 to 18,000

2 °) the diol is reacted with an at least stoichiometric amount of an Λ o aromatic and / or cycloaliphatic diisocyanate comprising a single benzenic or naphthalene nucleus

3) reacting at least one diamine chosen from aromatic diamines comprising a single benzenic ring, naphthalene or anthracene, and cycloaliphatic diamines. With the prepolymer, any excess of aromatic diisocyanate and with a cycloaliphatic disocyanate, the amount of diamine being sufficient to react with 90 to 100% of the total of available NCO groups

4 °) The molar ratio of the total of the aromatic diisocyanate and of the cycloaliphatic diisocyanate to the diol is included in the range 1, 2 to 4.0

5 °) At least some of the diisocyanate and / or diamine reagents have its two θ functional groups in the ortho or meta position

In a particularly advantageous manner, this process of the invention does not require the use of a catalyst, nor of mineral oil, nor the addition of a solvent in the prepolymer

The invention relates to elastomers having a polyurethane / polyurea block molecular chain comprising flexible polyether and / or polyolefin segments and rigid urethane and urea segments which can be prepared in two successive stages: -a first step of lengthening chains by condensation reaction leading to the preparation of a polyurethane prepolymer and -a second condensation reaction leading to the final elastomer The flexible and rigid segments according to the invention have the following characteristics:

1) the flexible segments are derived from one or more diols with terminal hydroxyl groups chosen from polyether diols, polyolefin diols and their combinations, the diols having a molecular weight of 650 to 18,000

As polyether diols suitable for this process, there may be mentioned for example:

H o polyoxytetramethylene glycol. Polyoxypropylene glycol. Polytetrahydrofuran. Polybutylene glycol

As polyolefin diols, mention may be made, for example, of: hydroxylated polybutadiene. Hydroxylated and hydrogenated polyisoprene With regard to the invention, polyether and polyolefin diols can be

45 used alone or in admixture in appropriate proportions

It is particularly preferable to use polytetrahydrofuran which is a linear diol having the formula: HO - [(CH2) 4-0] nH or n varies so that the molar mass is between 1700 and 3000, the range from 1900 to 2100 being preferred and as polyolefin diols hydroxylated polybutadienes and polyisoprenes

.2.0 hydroxyls and hydrogenated

Naturally, these diols can be used alone or in mixtures in suitable proportions.

2) The rigid urethane segments result from the reaction between the terminal hydroxyl groups of the diols and at least one aromatic diisocyanate comprising

& 5 a single benzenic or naphthalene nucleus and optionally a cycloaliphatic diisocyanate and / or mixtures thereof in suitable proportions. This first reaction constitutes the stage of formation of the prepolymer. It is carried out in a proportion range from 1.2 to 4.0 moles of the isocyanate (s) for one mole of diols.

30 Cycloaliphatic diisocyanates which can be used according to the invention: -transcyclohexane diisocyanate, 3-lsocyanatomethyl-3-3, 5 trimethyl cyclohexyl isocyanate

Aromatic dyisocyanates which can be used according to the invention -2.4 toluylene diisocyanate or a mixture of the two isomers 2.4 and 2.6 in the 5 ratios

80/20 to 65/35 or any other proportion, -1.5 naphthalene diisocyanate, paraphenilene diisocyanate, diphenylmethane diisocyanate (4,4 ') For the present invention it is advantageous to use: toluene diisocyanate (TDI): H3C-C6H3 ( NCO) 2.The isomers of toluene Λ o diisocyanate can be used alone or as a mixture. more particularly, it is preferable to use mixtures of conventional isomers in the proportions 80/20 as 2.4 / 2.6 isomers and 65/35 as 2.4 / 2.6 isomers. Naturally, the isocyanates can be used alone or as mixtures in appropriate proportions

45 3) The rigid urea segments result from the reaction between a diamine and the NCO groups of the prepolymer obtained in the first step and an excess of diisocyanate.

This second reaction results in a final crosslinking of the elastomer. The ratio of amine / free NCO groups must be such that 90 to 100% of the NCO.de sites.

2J0 preferably 98 to 100% react with diamine

The diamines which can be used in the invention are aromatic diamines comprising only one benzenic, naphthalene nucleus and / or cycloaliphatic diamines

As examples of diamines which can be used, mention may be made, for example, of: .2.5 2.6 toluylene diamine.cyclohexane diamine.la diethyltoluene diamine.la di (methylthio) toluene diamine.la bis (aminodiethyl) -3 (4), 8 (9) -tricyclo-

(5,2,1,0) decane, 1,5 diaminophthalene, 4,4 'methylene bis (3-chloro-2,6-diethylaniline) etc

Appropriate mixtures of such diamines can be used. For the present invention, it is advantageous to use toluene diamines and more particularly diethyltoluene diamine: (C2H5) 2 (CH3) C6H (NH2) 2 di (methylthio) toluene diamine: C9-H14-N2-S2

These diamines can be used alone or in mixtures in appropriate proportions S

The crosslinking condensation phase with diethyltoluene diamine gives a relatively short creaming time of the order of 7 to 20 seconds (depending on the rate of free NCO) which allows for certain applications to have a much shorter release time than traditional elastomers and, allows the A _Û implementation of this elastomer by spraying and "on shoot" system

The crosslinking condensation phase with di (methylthio) toluene diamine gives a relatively long cream time of the order of 15 to 300 seconds (depending on the level of free NCO and the type of diol used), which makes it possible to carry out parts of a certain volume or particular applications

-15 In a relatively advantageous way, it is possible to carry out the chain extension phase by condensation which constitutes the preparation of the polyurethane prepolymer with free isocyanate functions and, the condensation phase crosslinking of said prepolymer with the diamine without the need to employ a catalyst. The invention is based on the use of reagents having the following features: 0 1) The diisocyanates and diamines must be aromatic compounds having: a single aromatic ring or cycloaliphatic compounds making it possible to obtain short segments during the reaction and very rigid. This distinguishes the elastomers of the invention from known polyurethane-polyurea elastomers such as those of USA patent 4,218.54 which generally presents on one or

5-5 the other of the segments a diphenyl group (two aromatic rings) Among the best known are, for example, the formulations based on the following reactions of a diol with:

Toluene diisocyanate (TDI) and 3.3 dichloro-4,4 diamino diphenyl methane methylene- bis chloro aniline (MOCA) 5 Toluene diisocyanate / di-p-aminobenzoide of tπmethylene glycol

In these cases, on one or the other reagent (diisocyanate or amine), there are 2 aromatic nuclei which are separated either by a methyl group which constitutes an axis of rotation with low activation energy lowering the melting point of the link, or a longer chain but presenting the same effects to different degrees. ^• 10 The remoteness of the amine function over 2 benzenic nuclei (ie 2 aniline functions) also has the effect of reducing the reactivity of the diamine

2) The joint use of an isocyanate composed of a single aromatic nucleus and a cycloaliphatic diisocyanate - the first most reactive saturates the hydroxyl end groups of the diol and forms the recurring urethane pattern while the

A 5 cycloaliphatic diisocyanate comes in excess. Available for the second step.

The proportions of these two isocyanates can vary depending on the characteristics sought. They are in the range indicated with respect to the diol from 1.2 to 4.0 moles of diisocyanates for one mole of diol The proportion of aromatic diisocyanate should preferably be such that

Zt> will react to all of the hydroxyl groups in the diol

When using a cycloaliphatic diisocyanate having a "chair" conformation such as trans-cyclohexane diisocyanate. This gives great rigidity. This particularity is favorable to the desired qualities. The combination of aromatic diisocyanate / cycloaliphatic also provides better processability compared to the use of a cycloaliphatic alone. The aromatic isocyanate or the aromatic / cycloaliphatic mixture are preferably present in their entirety from the start of the reaction with the diol, which provides an excess of NCO groups which is essential to avoid solidification of the prepolymer. Excess between 1, 1 and 9%.

5 3) The position of the reactive groups on the aromatic and / or cycloaliphatic nucleus makes it possible to orient the stereochemical configuration of the polymer and consequently of its characteristics

Since the reagents used are di-functional, the reactive sites can be symmetrical

(in para) or asymmetrical (in ortho or meta) on the aromatic or Ao cycloaliphatic nucleus

The reaction leading to the formation of the rigid urea segments is carried out preferably close to the stoichiometric conditions to minimize the formation of bi urea branches.

Just as the first stage of formation of the urethane prepolymer is carried out so as to limit as much as possible by conventional and known means the allophanate connections.

In addition to the essential reagents indicated above, pore-forming agents may be included in the reaction mixture. Auxiliary agents and / or additives known in the chemistry of polyurethanes. As well as carbon fibers • ZΌ Examples of additive which are can add (not limiting):

It is possible to add one or more agents according to the desired characteristics and any other agent whose compatibility with polyurethanes has been proven.

Additives can be used alone or in mixtures: 5-antioxidants: (ex: IRGANOX 1010 .IRGANOX 1520 from CIBA)

-plasticizers-anti UV agents or UV absorbers

- novice agents: BYCK (BYCK CHEMISTRY)

NO AIR (BARLOCHER)

- pasty or liquid colorants - mineral fillers: barium sulfate, solid or hollow glass microspheres, silica.alumina.titanium oxide, black carbon, ceramics, mineral or metallic fibers, calcium carbonate etc .... - inorganic flame retardants such as flame retardants that: alumina hydrate, ammonium phosphates, phosphates and their derivatives, magnesium derivatives, zinc of bismuth, titanium and various other organics and their organobromo, organochlorine, non-chlorinated organophosphorus, chlorinated organophosphorus, 0 oxides antimony.organo nitrogen, etc ....

These flame retardants can be used alone or as a mixture in suitable proportions

It will be particularly preferred to use for the invention the ARYL PHOSPHATES ESTER alone or as a mixture and / or in combination with antimony oxides 5 The proportions of Aryl phosphate ester to be used being within the range of 5 to 20% by weight of the total mixture (by total mixture means the diol + isocyanate + diamine)

Preferably the percentage of Aryl phosphate ester will be in the range of 8 to 14% by weight of the total mixture and more particularly 12%. 0 The phosphate ester can be mixed completely and / or partly in each of the components (by component is meant prepolymer, diamine, diols and isocyanates)

In a particularly advantageous manner for the present invention, by mixing carbon fibers, preferably short, in a prepolymer based on polyolefin diols, preferably hydroxylated polybutadiene, a homogeneous distribution of said fibers is obtained, which allows, after setting complete work of the elastomer to obtain a loaded polyurethane elastomer having remarkable microwave absorption characteristics. as well as excellent resistance to hydrolysis The grammage of the fibers thus distributed depends on the desired microwave absorption results

The process is capable of being carried out in the liquid and / or more or less pasty phase (this depending on the processing temperature) using the conventional conventional means known from polyurethane technology. using reactors and low and / or high pressure casting machines fitted with a degassing system to obtain bubble-free products

It can also be used to make coatings in thin 0 layers, in particular by high pressure spraying, for example for coating complex parts, metallic wires and cables, coatings on metallic parts, as well as by coating on supports. non-woven fabrics, glass mats, metallic meshes or sheets etc ...

For the present invention, the methods of manufacturing the prepolymer can be multiple, but the method or methods described below are preferred:

In a reactor regulated at a temperature of 60 to 80 ° C, 75 ° C is preferred, equipped with a stirring system, a degassing and inerting system under nitrogen or another suitable gas. desired diol (s) or their mixture. preheated if necessary to a temperature around

^, 070 ° C; then the desired quantity of isocyanate (s) or their mixture is introduced. This amount depends on the desired level of free NCO in the final prepolymer.

After approximately 2 to 4 hours of reaction (depending on the type of diol or mixtures of diols used) in the reactor operating in the traditional way, a prepolymer having the desired excess NCO groups is obtained.

The reaction being exothermic, the temperature of the mixture rises to a temperature of approximately 85 ° C., then returns to control temperature. It is interesting to note that it is possible to obtain the same result by carrying out the mixing in a reactor controlled at a temperature of 90 ° C. and this for 45 to

30 60 minutes, but the solution at 75 ° C described above will be preferred for the invention. It is interesting to note that the "reactants" can be introduced into the reactor in any order and that this has no consequences on the final product, but we prefer for the present invention to introduce the diol (s) alone or in mixtures, then the isocyanate (s) alone or in mixtures as described above.

It is interesting to note that we can introduce the "additives" chosen alone or as a mixture, in whole or in part during the phase of introduction of the reactants or at the end of the reaction giving the prepolymer, this does not affect the desired results.

4θ In a particularly advantageous manner for the present invention, in order to obtain a flame retardant elastomer, the flame retardant is introduced alone or as a mixture, in whole or in part, either in the prepolymer, at the time of the introduction of the reactants into the reactor or at the end of the reaction, either in the formulated chain extender. which in this case requires vigorous mixing.

Once the prepolymer and the chain extender have been formulated, including the addition of the selected additives. Following the desired technical characteristics, the implementation to obtain an elastomer is carried out with the known means and installations for the elastomer preparation. thermosets - Low pressure casting machines (bi or multi components)

• 10 In a thermoregulated tank of 70 to 95 ° C depending on the type of diols or mixture of diols used, equipped with a degassing and inerting system under nitrogen (or other suitable gas), the prepolymer is introduced beforehand liquefied . In another thermoregulated tank of 25 to 50 ° C, equipped with a degassing and inerting system under nitrogen (or other suitable gas), the formulated chain extender is introduced or

• &5no; then the casting is carried out in the traditional way for this type of installation

For the present invention, it will be preferable to regulate the prepolymer tank at a temperature of 70/95 ° C. depending on the type of diol used and the chain extender tank at a temperature of 38/42 ° C., the supply circuits of the various components. at the • 30th pouring head will be regulated at the temperature of said components. The casting head will be regulated at the same temperature as the prepolymer In this case it is interesting to note that the viscosities of the 2 components are relatively close to each other

It is interesting to note that the lower the temperature of the prepolymer, the longer the cream time. 5 The appropriate mixture between the prepolymer and the chain extender carried out in the mixing head (or pouring head) is poured into thermoregulated molds at a temperature of 70 to 105 ° C. It will be preferred for the present invention a temperature close to 90 ° C.

Naturally any other system or process for implementing an elastomer A o thermosetting polyurethane can be used in the case of the invention such as for example "ribbon flow" or "continuous casting on a rotating tube with contiguous turns la spraying etc ...

The following examples will better understand the invention. All quantities expressed are parts by weight.

A Example N ° 1

First step: Preparation of the prepolymer:

In a thermoregulated reactor at a temperature of 75 ° C., provided with an agitator, a degassing and inerting system under nitrogen, the following are introduced:

As diol: 70 parts of a polytetrahydrofuran (PTHF) having a hydroxyl number • 10 of between 54.7 and 57.5 and of a molecular weight of between 1950 and 2050,

14 parts of a PTHF having a hydroxyl number between 60.6 and 64.1 and a molecular weight between 1750 and 1850.

As aromatic diisocyanate 16 parts of a toluene diisocyanate as a mixture of two isomers 2.4 and 2.6 in the ratio 80/20 • 2.5 The reaction is exothermic, the temperature of the mixture rises up to 85 ° C. then goes back down to the regulation temperature

After a reaction for 4 hours, a prepolymer having an excess of NCO groups of 4% is obtained.

Second step: In a low pressure casting (or injection) machine equipped with a mixing head for casting, the following is introduced: into the tank to contain the prepolymer regulated at a temperature of

90 ° C, the prepolymer prepared during the first stage which will be degassed and kept under nitrogen pressure in the other regulated tank at a temperature of 40 ° C reserved for diamine. Di- (methylthio) toluene is introduced diamine which will be degassed and maintained under nitrogen pressure.

The following are introduced into the mixing chamber of the casting head: -91.2 parts by weight of the prepolymer with 4% of excess NCO groups and 8.8 parts by weight of di- (methylthio) toluene diamine

The mixture is poured into a hot mold at 90 ° C.

This mixture has a cream time of the order of 60 seconds

The mold is then placed in post curing for 2 hours at 150 ° C. 45 An elastomer having a Shore A hardness of 80+ or -2 is thus obtained after 3 days at room temperature.

Example 2:

We follow the same operating order as that of example n ° 1

The reagents used are: "2O First step:

-Pre-polymer identical to Example 1.

-Diamine: diethyltoluenediamine

Second step:

-92.5 parts by weight of the prepolymer having 4% of excess NCO groups • 25 -7.5 parts by weight of diethyltoiuènediamine

The mixture is poured into a hot mold, preferably at 90 ° C.

Mixing at a cream time of about 20 seconds

The mold is put in post-baking between 30 minutes and an hour at 150 ° C

After 3 days at room temperature, an elastomer having a hardness of 30 Shore A 80 + or - 2 is obtained. Example 3

We follow the same procedure as for Example 1

First step Preparation of the prepolymer

As diols: 74.9 parts by weight of a polyoxytetramethylene glycol having a hydroxyl number between 54 and 56 and a molecular weight between 1900 and

2100

Diisisocyanate: 18.6 parts by weight of TDI 80/20

Fire retardant: 6.5 parts by weight of ARYLPHOSPHATE ESTER (REOFOS 50)

A prepolymer is thus obtained having an excess of NCO of 6% o Second step:

In the tank reserved for the chain extender (heated to 40 ° C), we introduce:

-68.1 parts by weight of di- (metylthio) toluene diamine

-31.9 parts by weight of ARYL PHOSPHATE ESTER (REOFOS 50)

This mixture is well homogenized, then degassed, then placed under an atmosphere of nitrogen.

The following are introduced into the mixing chamber of the pouring head:

-83.35 parts by weight of the prepolymer as described above

-16.65 parts by weight of the chain extender as described above

An elastomer is thus obtained having a Shore A hardness of 87 + or - 2 in accordance with £ 0 Fire standard UL 94 V 0

Example n ° 4 First step:

The following reagents are mixed in a reactor regulated at a temperature of 75 ° C. and placed under a nitrogen atmosphere with stirring, recycling and degassing: 5-100 parts by weight of a hydroxylated polybutadiene having a hydroxyl number of 48.2 and a molecular mass of 2800 (ex: Poly Bd 45 HT from ELF ATOCHEM) -100 Parts by weight of a hydroxylated polybutadiene having a hydroxyl number of 101.0 and a molecular mass of 1230 (ex: Poly Bd20 LM from ELF ATOCHEM ) -44.4 parts by weight of toluene diisocyanate in a mixture of 2.4 to 80% isomers and

2.6 to 20% (TDI 80/20)

The reaction is exothermic and brings the mixture to 85 ° C, then the latter gradually falls back to the regulation temperature. The reaction is stopped after 25 hours

The prepolymer thus obtained has an excess of NCO group of 4%

Second step:

In a machine this low pressure casting (or injection) equipped with a mixing head for casting is introduced: θ In the tank reserved for the prepolymer regulated at a temperature of 75 ° C, this degassed prepolymer is kept and maintained under pressure nitrogen

In another tank reserved for diamine, di- (methylthio) toluene diamine (EX: ETHACURE 300 CURATIVE from ETHYL) is introduced. This tank, which may contain other ingredients, is regulated at a temperature of 40 ° C under pressure A5 d 'nitrogen.

The following are introduced into the mixing chamber of the casting head:

-100 parts by weight of prepolymer with 4% excess NCO group

-9.7 parts by weight of di- (methylthio) toluene diamine

The mixture is poured into a hot mold, preferably at 95 ° C. ZD An elastomer is thus obtained having the following characteristics: Shore A hardness: 90

A temperature resistance characterized by a) 15 hours at 150 ° C. loss of initial hardness / Less 3 Shore A immediate After 30 minutes at room temperature: Less 2 Shore A “5 After 1 hour at room temperature: the initial value of 90 is found

Shore A b) 15 hours at 150 ° C then 2 hours at 180 ° C

Immediate hardness loss: Less 8 Shore A (therefore 82 Shore A)

After 30 minutes at room temperature: minus 4 Shore A (therefore 86 Shore A) $ ϋ After 2 hours at room temperature we return to the initial value of 90 Shore A

Water recovery: at 23 ° C for 240 hours: less than 0.03% at 100 ° C for 1 hour. less than 0.05% c) A relatively small loss of mass:

-1500 hours at 150 ° C under nitrogen: Weight loss less than 4%

-1500 hours at 150 ° C in air: Mass loss less than 4% S -1500 hours at 120 ° C in air: Negligible mass loss

Example 5:

We follow the same procedure as Example 4

The reagents used are as follows:

First step 10 -100 parts by weight of a hydroxylated polybutadiene having a hydroxyl number of

48.2 and molecular weight 2800 (Poly Bd 45 HT from ELF ATOCHEM)

-100 parts by weight of a hydroxylated polybutaduene having a hydroxyl number of

101.0 and molecular weight 1230 (Poly Bd 20 LM from ELF ATOCHEM)

-40 parts by weight of a polyisoprene having a hydroxyl index of 51.5 and 45 molecular weight 2500 (EPOL from ELF ATOCHEM)

-51.7 parts by weight of a toluene diisocyanate as a mixture of isomer 2.4 80% and

2.6 20% (TDI 80/20)

-7 parts by weight of antioxidant IRGANOX 1010

The prepolymer thus obtained has an excess of NCO group of 4% ^ 0 Second step:

Procedure identical to that of Example 4

-100 parts by weight of prepolymer above with 4% of excess NCO group

-9.7 parts by weight of di- (methylyhio) toluene diamine (ETHACURE 300)

An elastomer is thus obtained having the following characteristics: same as example 4 .2 / 5 Example 6

We follow the same procedure as for Example 4

The reagents used are as follows:

First stage

-100 parts by weight of a polyisoprene having a hydroxyl index of 51.5 and a 3 molecular Ornasse of 2500 (ex: EPOL from ELF ATOCHEM)

-19.25 parts by weight of a toluene diisocyanate as a mixture of 2,4-isomer (80%) and isomer 2.6 (20%)

The prepolymer thus obtained has an excess in NCO group of 4%

Second step

Same process as for example 4, but the tank reserved for the prepolymer is heated to 90 ° C.

The reagents used in the mixing chamber are as follows:

-100 parts by weight of the prepolymer having a rate of 4% in excess

-9.7 parts of di- (methyl) toiuene diamine (ETHACURE 300)

An elastomer is thus obtained having the following characteristics: 0 Shore A hardness: 86

Temperature resistance

After 15 hours at 150 ° C, then 15 hours at 180 ° C

Loss of hardness after 2 hours at room temperature. Less than 3 Shore A

Example 7: 5 First step: Preparation of the prepolymers

In a thermoregulated reactor at a temperature of 75 ° C. fitted with an agitator, a degassing and inerting system under nitrogen, the following are introduced:

-Polymer n ° 1

As diol 82 parts by weight of a polytetrahydrofuran having a hydroxyl number θ between 54.7 and 57.5 and a molecular weight between 1950 and 2050.

As aromatic diisocyanate 18 parts by weight of a toluene diisocyanate as a mixture of two isomers 2.4 and 2.6 in the ratio 80/20

The reaction is exothermic. The temperature of the mixture rises to 85 ° C, then drops back to the control temperature. After a reaction of 4 hours, a prepolymer having an excess of NCO group of 5% is obtained.

- Prepolymer # 2

In a second reactor are introduced:

As diol 40 parts by weight of a hydroxylated polybutadiene having a hydroxyl number of 48.2 and a molecular weight of 2800, 40 parts by weight of a hydroxylated polybutadiene having a hydroxyl number of 101 and a molecular weight from 1230 As aromatic diisocyanate: 20 parts by weight of a toluene diisocyanate as a mixture of the two isomers 2.4 and 2.6 in the ratio 80/20

After a reaction lasting 2 hours, a prepolymer having an excess of NCO group of 5% is obtained. Second step;

In a low pressure casting (or injection) machine, equipped to perform tri-component castings, we introduce:

In a tank to contain a prepolymer, the first prepolymer which will be regulated at a temperature of 90 ° C, degassed and maintained under nitrogen pressure -lo In another tank to contain a prepolymer, the second prepolymer which will be regulated at a temperature at 75 ° C, degassed and maintained under nitrogen pressure

In a tank reserved for diamine, di- (methylthio) toluene diamine is introduced which will be regulated at a temperature of 40 ° C degassed and kept under nitrogen pressure 45 The following is introduced into the mixing chamber of the casting head:

-71.4 parts by weight of the first prepolymer

-17.8 parts by weight of the second prepolymer

-10.8 parts by weight of di- (methylthio) toluene diamine

The mixture is poured into a mold heated to 90 ° C • 10 The mold is placed in post-baking at 150 ° C for 2 hours

An elastomer having a hardness is obtained after 3 days at room temperature

Shore A of 87

Example 8

First step: Preparation of the prepolymer: 5 In a thermoregulated reactor at a temperature of 75 ° C., equipped with an agitator. With a degassing and inerting system under nitrogen (or other suitable gas), the following are introduced: As diol : 78.12 parts by weight of a polytetramethylene glycol having a hydroxyl number between 54 and 56 and a molecular weight between 1900 and 2100 As aromatic diisocyanate 21.88 parts by weight of a toluene diiscyanate as a mixture of two isomers 2.4 and 2.6 in the ratio 80/20 (TDI 80/20)

The reaction is exothermic, the temperature of the mixture rises to 85 ° C, then falls back to the control temperature. After a reaction for 4 hours, a prepolymer having an excess of NCO groups of 7% is obtained.

Second step:

In a low pressure casting machine fitted with a mixing head for casting, the following are introduced:

In the tank to contain the prepolymer, regulated at a temperature of 90 ° C, the 40 prepolymer prepared during the first stage which will be degassed and kept under nitrogen pressure

In another tank regulated at a temperature of 40 ° C., reserved for diamines, 64.35 parts by weight of di- (methylthio) to! Uene diamine and 35.65 parts by weight of diethyltoluene diamine are introduced. The whole will be well mixed, degassed and kept under nitrogen pressure.

Is introduced into the mixing chamber of the pouring head (regulated at a temperature of 90 ° C):

-86.35 parts by weight of prepolymer with 7% of excess NCO groups and 13.65 parts by weight of the mixture of diamines "tO The mixture is poured into a mold heated to 90 ° C. The mold is then put into post baking 2 hours at 150 ° C

A polyurethane-polyurea elastomer having a Shore A hardness of 97 + or - 2 is thus obtained after 3 to 5 days at room temperature.

Claims

1) Polyurethane-polyurea elastomers having very good resistance to high temperatures equal to or greater than 150 ° C. and / or excellent resistance to hydrolysis and / or remarkable flame resistance. From a prepolymer having groups free isocyanates and diamines characterized in that:

5 a) The flexible segments derived from diols chosen from polyether diols such as polytetrahydrofurans. Polyoxytetramethylene glycol, polyoxypropylene glycol, polybutylene glycol, and polyolefin diols with terminal OH groups such as hydroxyl polybutadienes or hydroxyl or hydrogenated polyisoprenes These diols can be used alone or in mixtures

4o These diols have a molecular weight of between 650 and 18,000 b) The urethane segments are mainly derived from an aromatic isocyanate chosen from 2,4 toluene diisocyanate. A mixture of 2,4 and 2,6 isomers of toluene diisocyanate, paraphenylene diisocyanate, diphenylmethane diisocyanate 4,4 and / or a cycloaliphatic diisocyanate chosen from transcycloexane

A $ diisocyanate, 3-isocyanomethyl 3-3.5 trimethyl cyclohexyl isocyanate These isocyanates can be used alone or in mixtures c) The urea segments are mainly derived from an aromatic diamine chosen from 2.6 toluene diamine. Diethyltoluene diamine. di (methylthio) toluene diamine and / or a cycloaliphatic diamine such as cyclohexane diamine

“&> These diamines can be used alone or in mixtures d) The preparation of the prepolymer, then of the elastomer does not involve the addition of solvent, nor the use of catalyst or mineral oil. e) The addition of blowing agents, auxiliary agents or other additives can be done in any of the reagents or in distribution in the different reagents. f) The reagents used in the invention are reagents which are found in the state in the trade g) The preparation of the prepolymer is carried out hot in a temperature range from 45 ° C to 90 ° C 5 h ) The processing of the elastomers is carried out hot

2) Process for the preparation of polyurethane-polyurea elastomers according to claim N ° 1 consisting in carrying out the reaction of at least one diol and of an excess of at least one diisocyanate to form a polyurethane prepolymer having free NCO groups then the reaction of the NCO groups of the prepolymer thus obtained with at least one diamine to form a polyurethane-polyurea characterized in that: a) The diol is chosen from hydrogenated hydroxyl polyisoprenes having a molecular weight of between 650 and 18,000. hydrogenated hydroxylated polyisoprene can be used alone or in mixtures with other diols whose compatibility has been

45 demonstrated b) The diol or the mixture of diols is reacted with at least a stoichiometric amount of a reagent or a mixture of diisocyanate reagents comprising a single benzenic or naphthalene nucleus chosen from the 2,4 toluene diisocyanate, a mixture 2,4 and 2,6 toluene diisocyanate isomers,

• 2o diphenylmethene diisocyanate 4,4, transcyclohexane diisocyanate to obtain a prepolymer. c) The prepolymer is reacted with at least one diamine or a mixture of aromatic diamines comprising a single benzenic or naphthalene nucleus chosen from 2.6 toluene diamine.la diethyltoluene diamine.la di-

^ 5 (methylthio) toluene diamine. The quantity of diamine being sufficient to react with 90 to 100% of the total of the free NCO groups of the prepolymer. d) At least some of the diisocyanate and diamine reagents have functional groups in the ortho or meta position 3) Process for preparing polyurethane-polyurea elastomers according to claim N ° 1 consisting in carrying out the reaction of at least one diol and of an excess of at least one diisocyanate to form a polyurethane prepolymer having free NCO groups then the reaction of the NCO groups of the prepolymer as well

5 obtained with at least one diamine to form a polyurethane-polyurea elastomer characterized in that: a) the diol is chosen from hydroxylated polybutadienes in admixture with one another. Having a molecular weight of between 650 and 18,000. The mixture of polybutadienes with d other diols whose compatibility has been

As demonstrated can be used b) The mixture of diols is reacted with an at least stoichiometric amount of a reagent or a mixture of diisocyanate reagents comprising a single benzenic or naphthalene nucleus chosen by the 2,4 toluene diisocyanate, a mixture 2,4 and 2,6 toluene diisocyanate isomers, diphenylmethane diisocyanate4,4,

AS transcyclohexane diisocyanate, to obtain a prepolymer c) The prepolymer is reacted with at least one diamine or a mixture of aromatic diamines comprising a single benzenic or naphthalene ring chosen from 2.6 toluene diamine.diethyl toluene diamine.la di ( methylthio) toluene diamine. the quantity of diamine being sufficient to react with 0 90 to 100% of the total of the free NCO groups of the prepolymer d) At least part of the reagents diisocyanate and diamine have functional groups in postionortho or meta

4) Process for the preparation of polyurethane-polyurea elastomer according to claim N ° 1 consisting in carrying out the reaction of at least one diol and of an excess of at least one diisocyanate to form a polyurethane prepolymer having NCO groups then the reaction of the NCO groups of the prepolymer thus obtained with at least one diamine to form a polyurethane-polyurea elastomer, characterized in that: a) The diol is chosen from polyether diols having a molecular weight of between 650 and 18,000 and more especially from polyoxytetramethylene glycols, polytetrahydrofurans, polyoxypropylene glycols, polybutylene glycols used alone or as mixtures with one another or as mixtures with diols

5 polyolefins with terminal OH groups. b) The diol or mixture of diols is reacted with an at least stoichiometric amount of a reagent or a mixture of diisocyanate reagents comprising a single benzenic or naphthalene nucleus chosen from the 2,4 toluene diisocyanate, a mixture of the isomers 2.4 and 2.6 toluene diisocyanate, the

-lo diphenylmethane diisocyanate 4, 4, transcyclohexane diisocyanate to obtain a prepolymer c) The prepolymer is reacted with at least one diamine or a mixture of aromatic diamines comprising a single benzenic or naphthalene nucleus chosen from 2.6 toluene diamine.la dietyltoluene diamine.la di (methylthio) toluene

45 diamine. The quantity of diamine being sufficient to react with 90 to 100% of the total of the free NCO groups of the prepolymer d) At least some of the diisocyanate or diamine reagents have functional groups in the ortho or meta position

5-Polyurethane-polyurea elastomers according to Claims 2, 3 and 4 characterized in that the molar ratio of the total of isocyanate to diol is in the range from 1, 2 to 4

6 Process according to any one of claims 2 to 5 is that the percentage of free isocyanate groups in the prepolymer, derived from the mixture diol diisocyanate to isocyanate groups having reacted with the diol is between 1 ^• 25, 1 and 9 %. 7-Process according to any one of Claims 2 to 6, characterized in that the diisocyanate or the mixture of diisocyanates reacted with the diol in the stage of preparation of the prepolymer is a mixture of aromatic diisocyanates as defined and of a cycloaliphatic diisocyanate and that the amount of aromatic diisocyanate is sufficient to react with all of the hydroxyl groups of the diol

8-Process for preparing a flame retardant polyurea polyurethane elastomer according to claim N ° 4 characterized in that: a) The addition of flame retardants alone or in mixtures in one or more of the reactants of the total mixture (diols + isocyanates + diamines ) gives the elastomer 4 o remarkable flame retardant characteristics b) The flame retardant or the mixture of flame retardants is chosen from aryl phosphate esters, antimony oxides, borax c) The addition of 8 to 14%, preferably 12% by weight of the total reactants, of aryl phosphate ester gives the elastomer a FIRE UL 94 VO classification (according to 5 prescriptions of Standard NF ISO 1210)

9-A method according to claim No. 3 characterized in that: a) The addition into the mixture of hydroxylated polybutadiene or in the prepolymer based on hydroxylated polybutadiene of short carbon fibers gives the polyurethane-polyurea elastomer characteristics d 'absorption of remarkable microwaves <lo b) The distribution of short carbon fibers is done in a homogeneous manner even in the case of manual mixing c) The elastomer thus obtained combines characteristics of microwave absorption and resistance remarkable hydrolysis and sea air

/ 10-Polyurethane-polyurea elastomers according to claims 2,3,5,6,7,9 characterized in that: a) They have a very good resistance to hydrolysis and at a temperature above

150 ° C continuously and at 180 ° C at peak (for 2 hours) b) They have very good resistance to thermal aging and that the loss of mass is relatively low 5 -1500 hours at 150 ° C under nitrogen: loss of mass less than 4%

-1500 hours at 150 ° C in the loss of mass below 4%

-1500 hours at 120 ° C in air: negligible loss of mass c) The addition of powdered ceramics (ALN, AL203 etc ...) in proportions of

25 to 60% changes the thermal conduction from 0.2 to 1.2 W / M / H -10 d) The water absorption is less than 0.05% at 23 ° C and 0.1% after one hour in water at 100 ° C

11 -Polyurethane elastomers -Polyurea flame retardant or not according to claims 4 and 8 characterized in that: a) The elastomers withstand a temperature range between -60 and + 45 220 ° C (peak) b) The elastomers comply automotive standard T3 (240 hours at 150 ° C) c) These elastomers in the flame retardant version comply with the UL 94 V0 Fire Standard (according to ISO 1210 classification F.VO classification)