AU687982B2

AU687982B2 - Polyurethane elastomer formulation based on polydiene polyol and castor oil having improved dampening properties

Info

Publication number: AU687982B2
Application number: AU15045/95A
Authority: AU
Inventors: Jean-Jacques Flat
Original assignee: Elf Atochem SA
Current assignee: Arkema France SA
Priority date: 1994-03-23
Filing date: 1995-03-23
Publication date: 1998-03-05
Anticipated expiration: 2015-03-23
Also published as: NO951098L; NO951098D0; KR100264684B1; BR9501164A; FR2718453A1; JPH0853530A; DE69507527T2; FR2718453B1; KR950032359A; NO306955B1; CA2146269A1; EP0676432B1; EP0676432A1; AU1504595A; FI951348A; ATE176255T1; FI951348A0; DE69507527D1

Abstract

A polyurethane elastomer compsn. contains (a) a polydiene polyol, (b) castor oil, (c) opt. a polyol with low mol. wt., and (d) a polyisocyanate with at least 2 NHCO gps., with the amt. of castor oil being sufficient to give (i) a delta tangent (tg delta) of at least 0.2, measured at the Tg of the compsn., this being at least -20 deg. C, and (ii) a Shore hardness of 30 A to 80 D according to DIN 53505.

Description

IUW1 1 2&1W01 Rogulation 3.2(2)

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: POLYURETHANE ELASTOMER FORMULATION BASED ON POLYDIENE POLYOL AND CASTOR OIL HAVING IMPROVED DAMPENING

PROPERTIES

r The following statement is a full description of this invention, including the best method of performing it known to us I, ~L- 1 POLYURETHANE ELASTOMER FORMULATION BASED ON POLYDIENE POLYOL AND CASTOR OIL HAVING IMPROVED DAMPENING PROPERTIES The present invention relates to a polyurethane elastomer formulation based on polydiene polyol and castor oil having improved dynamometric and dynamic (dampening) mechanical properties.

Russian patent SU 364646 describes polyurethane compositions constituted by 5 to 25 parts by weight of castor oil to 100 parts by weight of polydiene diol.

Introduction of castor oil contributes to the significant improvement of certain dynamometric mechanical properties such as tensile strength.

However, there is no indication given in this patent of the dynamic mechanical properties of k the compositions obtained.

Japanese patent JP 05039344 describes polyurethane compositions based on hydrogenated polydienediols, castor oil and softener.

These plasticised compositions based on hydrogenated polydienediols can be used in particular in applications requiring dynamic, or dampening, mechanical properties.

These compositions, however, are based exclusively on hydrogenated polydienediols and are also plasticised, effectively restricting certain mechanical properties such as breaking stress and hardness.

Japanese patent JP 62/135512 relates to polyurethane compositions based on a mixture of polyols constituted by a liquid polydiene polyol and/or castor oil, and a polyol consisting of a copolymer of tetrahydrofurane and ethylene oxide and/or propylene oxide.

These compositions exhibit hardnesses which range little at low temperature.

This particular patent does not mention or suggest any improvement in mechanical properties, especially in dampening properties.

I _I- For certain applications it is necessary to have polyurethane elastomer formulations which exhibit said dampening properties in a temperature range which is staggered generally from -20 0

C

to 1000 0

C.

Dampening properties is currently understood to mean the faculty of a material to attenuate nuisances caused by possibly reverberating vibrations.

The dampening properties of an elastomer material more or less cross-linked are generally well represented by dynamic mechanical properties and especially by its delta tangent, hereinafter represented by tgS, which is given as E tg8

E'

o1 in which E" represents the loss module, and E' represents the conservation module.

In general, in the field currently in question it is agreed that a material is dampening when, for example, tg8 is greater than 0.5 for a given temperature range.

A polyurethane elastomer formulation has now been found comprising at least a polydiene polyol, castor oil, optionally at least one polyol of low molecular mass and at least one polyisocyanate having at least two isocyanate functions, characterised in that it comprises a sufficient quantity of castor oil to produce a/ a delta tangent tg8 at least equal to 0.2 and preferably between 0.5 and measured at the vitreous transition temperature Tg of said formulation which is at least equal to -20°C, and b/ a Shore hardness varying from 30 A to 80 D and preferably between 50 A and 60 D, measured according to DIN 53505.

The values of E' and E" of the expression

E"

tg

E'

d~l I L- I I IL~ _I 2- I expressed in MPa are obtained as a function of the temperature which ranges from -1200C to +150°C, by stressing the polyurethane elastomer material in dynamic traction.

The standardised test piece is clamped between the jaws of a mechanical spectrometer, subjected to an initial pressure then stressed in dynamic traction at a frequency of 1.66 Hz corresponding to a pulse of 10 rad/s. The dephasing measure between the imposed stress and the stress transmitted by the test piece gives access to the values of the E' and E" modules and, consequently, to tg8 and this over the whole range of temperatures studied.

According to the present invention, the polydiene polyol is a hydroxytelechelically conjugated diene oligomer which may be obtained by means of various procedures such as radical polymerisation of conjugated dienes having from 4 to 20 carbon atoms in the presence of a polymerisation softener such as hydrogen peroxide or an azoic compound such as azobis- 2,2'[methyl-2,N-(hydroxy-2-ethyl)propionamide] or anionic polymerisation of conjugated dienes having from 4 to 20 carbon atoms in the presence of a catalyst such as dilithium naphthalene.

Also according to the present invention the conjugated diene of the polydiene polyol is selected from the group comprising butadiene, isoprene, chloroprene, 1,3-pentadiene and S cyclopentadiene.

.According to the present invention, a butadiene-based polydiene polyol will preferably be I; used.

It would not be going beyond the scope of the invention to use hydrotelechelic butadiene oligomers epoxied on the chain.

According to the present invention also, the polydiene polyols may have molar masses at most equal to 7000 and preferably between 1000 and 3000. They exhibit functionalities ranging from 1 to 5 and preferably from 1.8 to 3.

Examples of polydiene polyols are hydroxyl polybutadienes marketed by Elf Atochem S.A.

under the name Poly Bd® 45 HT and Poly Bd® 20 LM.

The castor oil according to the present invention may be constituted by a mixture of fatty acid glycerides such as ricinoleic acid, oleic acid, linoleic acid, stearic acid and dihydrostearic acid.

It has a hydroxyl index between 2 meq/g and 4 meq/g and a viscosity at 20 0 C between 935 and 1033 MPa.s.

It is preferred to use a castor oil according to the present invention containing at least of ricinoleic acid glyceride.

It would not be going beyond the scope of the invention to use a castor oil which is partially or totally hydrogenated as well as partially or totally transesterified.

According to the present invention the polyurethane elastomer formulation may further comprise castor oil and at least a polyol of low molar mass.

Polyol of low molar mass is understood to mean polyols having molar masses ranging from to 800.

Examples of such polyols are ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,4-butane diol, 1,6-hexane diol, 2-ethyl hexane-1,3-diol, N,Nbis(hydroxy-2-propyl)aniline, 3-methyl-1,5-pentanediol, trimethylol propane, pentaerythritol, propoxyl bis phenol A marketed by AKZO under the name DIANOL 320 and the mixture of at least two of the above polyols.

According to the present invention, the polyisocyanate used can be an aromatic, aliphatic or cycloaliphatic polyisocyanate having at least two isocyanate functions in its molecule.

Examples of aromatic polyisocyarate are 4,4-diphenylmethane diisocyanate (MDI), modified liquid MDI's, polymeric MDI's, 2,4- and 2,6-toluylene diisocyanate (TDI) as well as their mixture, S xylylene diisocyanate (XDI), paraphenylene diisocyanate (PPDI), 1,5-naphthalene diisocyanate (NDI), triphenylmethane triisocyanate, tetramethylxylylene diisocyanate (TMXDI).

Of the aromatic polyisocyanates, the invention preferably relates to 4,4'-diphenyl methane o. diisocyanate and most particularly modified liquid MDI's.

Examples of aliphatic polyisocyanate are hexamethylene diisocyanate (HDI) and its derivatives and trimethylhexamethylene diisocyanate.

Examples of cycloaliphatic polyisocyanate are isophore diisocyanate (IPDI) and its S derivatives, 4,4'-dicyclohexylmethanediisocyanate and cyclohexyl diisocyanate (CHDI).

a The quantity of polyisocyanate according to the present invention is selected such that the molar ratio NCO/OH is between 0.6 and 2 and preferably between 0.8 and 1.2.

Other reactive compounds can be used which comprise functions capable of reacting with the isocyanate functions; the molar ratio would have to be calculated by taking into account the presence of said functions of these reactive compounds.

With reference to said reactive compounds capable of entering the formulation according to the present invention, diamines having molar masses ranging from 60 to 5000 may be mentioned.

Examples of such diamines are ethylene diamine, diphenyl methane diamine, isophoronediamine; polyoxypropylenes, polyoxytetramethylenes andpolybutadienes resulting from amine functions.

The mechanical and dampening properties of the formulations according to the present preferoAbly invention will be achievable by using at least 25 parts by weight of castor oil to 100 parts by weight of polydiene polyol and preferably 50 to 150 parts by weight.

In the variant where, apart from the castor oil, the formulation comprises at least a polyol of low molar mass, at most 100 parts by weight of polydiene polyol will be used, and preferably to 50 parts by weight.

Even though the use of a catalyst is not indispensable, in certain cases, if required, a catalyst can be used which may be selected from the group comprising tertiary amines, imidazoles and organometallic compounds.

Examples of tertiary amines are 1,4-diazo-bicyclo[2.2.2]octane (DABCO), pentamethyldiethylene triamine.

Examples of organometallic compounds are tin dibutyldilaurate and tin dibutylacetate.

The polyurethane elastomer formulation according to the present invention can be obtained according to a process known as a 'one-shot' process, which consists of mixing polydiene polyol, i: d castor oil, optionally polyol of low molar mass, optionally in the presence of a catalyst and fillers or other additives in a reactor under mechanical agitation at a temperature ranging from ambient temperature (20 0 C) to 100 0 C, at atmospheric pressure or under reduced pressure Polyisocyanate is added to the mixture thus obtained and this is homogenised for a period which may vary from 1 to 5 minutes, then the reactive mass which is left is poured at ambient temperature for at least 24 hours, after which cross-linking is almost complete.

Examples of additives which can be introduced to the formulation are anti-UV agents, antioxidants and tackifying resins.

With reference to fillers which can be added, mention can be made of calcium carbonate, barium sulfate, silica, magnesium and aluminium hydroxides, titanium, talc, graphite, clays, hollow 13 'T Oi silica micro -heres and carbon black. Petroleum bitumens and coal pitch may also be incorporate i the formulations.

Adjusting of the proportions of castor oil and optionally of the polyol of low molar mass produces polyurethane elastomer formulations which exhibit good dampening properties in a temperature range of -20 0 C to around 100 0

C.

Furthermore, these formulations have an ultimate tensile strength, tearing resistance and a hardness greater than the base formulations of polydiene polyol only.

The formulations according to the present invention find application especially as dampening resins in multi-layer compositions such as steel/resin/steel sheet sandwich or in coated sheets used in automobile applications (body, underbody) or even in industrial applications (soundproofing of compressors, washing machines and other electrical household appliances).

The following examples illustrate the invention.

The formulations have been prepared by using the following constituents Poly Bd® 45 HT hydroxyl polybutadiene of Mn equal to 2800 (determined by steric S1exclusion chromatography) having a o 1 0 hydroxide index expressed in milliequivalent per gram (meq/g) equal to 0.83, a viscosity (MPa.s at 30 0 C) equal to 5000 and a density 'equal to 0.90; Poly Bd® 20 LM: hydroxyl polybutadiene of Mn equal to 1300 having a lo hydroxide index equal to 1.70 meq/g, a viscosity equal to 1600 MPa.s at 30°C and a density equal ao. to 0.90; castor oil: mixture of fatty acid glycerides containing at least 85% by weight of ricinoleic acid, having a loH hydroxide index equal to 2.93 meq/g and a dynamic viscosity equal to 600 MPa.s at 30 0

C;

2-Ethyl- 1,3-hexanediol; N,N bis(hydroxy-2-propyl) aniline marketed by Dow Chemicals under the name VORANOL RA 100; MDI 143 modified liquid polyisocyanate containing 80% by weight of MDI monomer and 20% by weight of modified MDI, exhibiting an NCO function percentage equal to 29%, marketed by Dow Chemical under the name ISONATE 143.

I LI Preparation of the formulations The formulations were prepared according to the technology known as the 'one-shot' process.

The Poly Bd, castor oil and the polyols of low molar mass (Voranol RA 100 or 2-ethyl-1,6hexanediol) are introduced, in accordance with the proportions listed in Tables 1, 2 and 3, into reactor, then mixed by a mechanical agitator turning at 200 rpm over a period of 1 hour at a temperature of 80°C and under reduced pressure.

The polyisocyanate is then added in an NCO/OH ratio such as indicate in Tables 1, 2 and 3, and the whole is homogenised for 2 minutes; the reactive mass is then poured into a mould.

This is left to cross-link at ambient temperature over 24 hours.

In Tables 1, 2 and 3 the proportions of the various constituents of the formulations are expressed in parts by weight.

Standardised test pieces are cut from the resulting cross-linked elastomer product, by which the following mechanical properties are determined SMechanical (dynamometric) mechanical properties breaking elongation and elongation stress determined according to DIN standard 53504 tearing performed on test pieces known as 'breeches' according to ISO standard R 34 Shore hardness according to DIN standard 53505.

Mechanical (dynamic) properties Vitreous transition Tg (in delta tangent to vitreous transition Tg and elasticity module E' at 20 0 C (in MPa) are determined on a type RSA 2 mechanical spectrometer marketed by Rh6ometrics.

'The analyses are performed on test pieces measuring 22.6.2 mm, stressed in dynamic traction with a pulse of 10 rad/s, corresponding to a frequency of 1.66 Hz.

Treatment is carried out between -120 0 C and +150 0 C at the abovementioned frequency.

From the curves there is access to the E' module at 20°C, tg8 and Tg.

Listed in Tables 1 and 2 are the results of the dynamometric test results, while Table 3 shows the mechanical (dampening) properties.

8 The introduction of castor oil into the formulations based on Poly Bd® 45 HT polydiene polyol examples 6 to 10 in Table 1 causes a strong increase in the tearing, breaking stress and hardness of the formulations according to the present invention relative to the reference formulations of examples 1 to 5 in Table 1.

Equivalent results are obtained with formulations based on Poly Bd® 20 LM polydiene polyol.

These results are itemised in Table 2, by comparing the mechanical properties of the formulations of examples 16 to 20 according to the present invention to the reference formulations of examples 11 to As for the dampening properties in Table 3, it is noted that the formulation examples of castor oil of examples 1, 4 and 5 are dampening at low temperatures (-60 0 C) and E' module at ambient temperature is low.

The introduction of castor oil into formulations also based on Poly Bd® 45 HT in examples 6, 8, 10 and 21, and based on Poly Bd® 20 LM in examples 16 to 20 produces dampening properties over effective temperature ranges of around -20 0 C to In fact, for these formulations tg5 is between 0.78 and 0.91 and furthermore, the E' modules at ambicnt temperature are very elevated and reach 500 MPa, thus imparting to the polyurethane elastomer material good mechanical properties such as good resistance to compression.

It is also evident that the use of a polyol of low molar mass (Voranol RA 100 or 2-ethyl-1,3hexanediol) allows advantageous control of the position ofTg of 0OC to +60°C with increased tg8 values.

*a I 9 TABLE I

CONSTITUENTS

OF THE

FORMULATION

Poly Bd: 45 H Koranol RA 100 2-Ethyl-i ,3-hexanediol_ jNCO/OH ratio MECHANICAL PROPERTIES Braigelongation(% Breaking stress (MPa) Tear (N/mm; Shore hardness (A or D)

EXAMPLES

-i 1 2 0 100 10 3 7 100

'I

100~~ 1.05 7 50 50 10 1.05 so 9 50 50 -K 10~7ii 1.05 1.05 1.05 20 1.05 1.05 1.05 1.0 4 4- 100 1 2 5 45A 258 -4-7.9 20.4 63- 208 14 29.1 71A 296 6.4 18.4 61 A 198 11.5 29.6 73A 9.3 50A 1618 16.7 31 D 11 164 23.6 123 60D 192 13.1 45 83A 206 15.7 TABLE 2

CONSTITUENTS

OF THE

FORMULATION

Poly Bd®@ 20 LM Castor oil Voranol RA 100 2-Ethyl-i ,3-hexanediol NCO/OH ratio MECHANICAL PROPERTIES

EXAMPLES

1 12 )0 100 10 1.05 1 ~13 100 20 054 147 10 1.05 100 20 1.05 10 50-1 50 1.05 1.05 18 50 50 1.05 05 1.05 Breaking elongation(% Breaking stress (MPa) Tear {N/mm) Shore hardness (A or 0) 113 2 48A 292 11 9 20 .8 _j 49A 220 18.7__ 59.8 85A i

I

303 10.0 19.2 258 18.8 59.9 110 2.2 7.5 55A 182 15.3 34 23D 28.7 113 60D 208 14.5 32 250 201 23.8 94 510D 0 a *0 TABLE3 EXAMPLES CONSTITUENTS OF THE__

FORMULATION

Poly Bdo 45 HT 10 Poly Bd®D 20 LM Castor oil Voranol RA 100 2-Ethyl-i ,3-hexanediol NCO/OH ratio MECHANICAL PROPERTIES Tg (AC) tg( (at Tg) E' module (MPa) at 20AC 0 1.05 0.79 3 4 5 10 100% 10 1 .05 -60 0.49 10 20 8 19 10 1.05 1.05 32 46 0.78 0.78 100__ 400 1.0 -0 _-2 0.40 0.91 301 2.5

V

Claims

1. Polyurethane elastomer formulation when used as a dampening agent comprising at least a polydiene polyol, castor oil, optionally at least a polyol of low molar mass and at least one polyisocyanate having at least two isocyanate functions, characterised in that it comprises a sufficient quantity of castor oil to produce: a/ a delta tangent tg8 as defined at page 2 herein, at least equal to 0.2 and preferably between 0.5 and 1.5, measured at the vitreous transition temperature Tg of said formulation which is at least equal to -20°C, and b/ 3 Shore hardness varying from 30 A to 80 D and preferably between 50 A and 60 D, measured according to DIN 53505.

2. Formulation as claimed in Claim 1, characterised in that tg8 is between 0.5 and e 3. Formulation as claimed in Claim 1, characterised in that the Shore o"o hardness is between 50 A and 60 D.

4. Fo. 'ilation as claimed in Claim 1, characterised in that the castor oil is a mixture of ricinoleic, oleic, linoleic, stearic and dihydrostearic acid glycerides. a* Formulation as claimed in Claim 4, characterised in that the castor oil comprises at least 85% of ricinoleic acid glyceride. a

6. Formulation as claimed in any one of Claims 1 to 5, characterised in that it comprises at least 25 parts by weight of castor oil to 100 parts by weight of polydiene polyol. \,dALL\ 7. Formulation as claimed in Claim 6, characterised in that it comprises at I I I I I least 50 to 150 parts by weight of castor oil to 100 parts by weight of polydiene polyol.

8. Formulation as claimed in Claim 1, characterised in that the polydiene polyol is an oligomer of hydroxytelechelically conjugated diene.

9. Formulation as claimed in Claim 8, characterised in that the conjugated u!ene is butadiene. Formulation as claimed in Claim 1, characterised in that the polydiene polyol has a molar mass at least equal to 7000.

11. Formulation as claimed in Claim 10, characterised in that the polydiene polyol has a molar mass of between 1000 and 3000.

12. Formulation as claimed in Claim 1, characterised in that the polydiene has a functionality ranging from 1 to

13. Formulation as claimed in Claim 1, characterised in that the polyisocyanate is an aromatic polyisocyanate.

14. Formulation as claimed in Claim 13, characterised in that the aromatic polyisocyanate is a modified liquid MDI.

15. Formulation as claimed in Claim 1, characterised in that the polyol has a molar mass ranging from 50 to 800.

16. Formulation as claimed in Claim 1, characterised in that it comprises at least 100 parts by weight of at lease one polyol of low molar mass to 100 parts by weight of polydiene polyol. S 'U 14

17. Application of the formulation as claimed in any one of Claims 1 to 16 as a dampening resin for a metallic sheet sandwich or coated sheet. DATED this 1st day of November, 1997. ELF ATOCHEM S.A WATERMARK PATENT TRADEMARK ATTORNEYS 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA LCG/CJH:BA VAX DOC 018 AU1504595. WPC o D or r r r r o sc o c o a r =R I I 1 0 ABSTRACT The present invention relates to a polyurethane elastomer formulation based on a polydiene polyol and caster oil, which comprises a sufficient quantity of castor oil to produce: a) a delta tangent at least equal to 0.2, measured at the vitreous transition temperature Tg of said formulation which is at least equal to -200C, and b) a Shore hardness varying from 30 A to 80 D. Application of said formulation as a dampening resin in multi-layered compositions such as metallic sandwich or coated sheet. 0 0* 0 0 go• eoe ee