CA1163749A - Resistant epoxy coatings - Google Patents

Abstract

ABSTRACT
The invention relates to polymeric coatings and in particular coatings formed by reaction of an epoxy resin and a polyisocyanate where the former disadvantages of slow curing of the resins has been overcome by introducing into the epoxy resin molecule, primary hydroxyl groups which react with the isocyanate groups of the polyisocyanate much more readily and rapidly compared with the indigenous secondary hydroxyl groups. Particularly the resin component comprises the reaction product of a diol of formula:
HO-CH2- (R)a -CH2-OH
wherein R is a straight or branched chain alkylene group having at most 6, and preferably three, carbon atoms, of the cyclohexane group where a is 0 or 1. Particularly the epoxy is selected from a preferred group of low molecular weight diglycidyl ethers of Bisphenol A and may include other components. These compositions are particularly weather resistant.

Description

7 ~ 9 BAC~CGROUND OF INVENTION

The present invention relates to polymeric coatings and in particular such coatings when formed by the reaction of an epoxy resin and a polyisocyanate.

PRIOR ART

It is well know that diglycidyl ethers of Bisphenol A (DGEBA) epoxy resins of the following formula: A

CH3 CH~
CH~-CH-CH~ -O ~ C ~ O-CH2-ClH-CH2 -O ~ -C ~ o-CH2-C~-~H2 wherein n ~ 2, react with polyisocyanates to produce, by cross-linking, chemical coatings which are resistent to a variety of chemicals. Since the reaction between the epoxy resin and the polyisocyanate, (the resin is said to have been "cured" by the isocyanate), commences immediately upon mixing of those components, the coating "composition" is supplied as a two component unit or "kit"; one component comprisins the epoxy resin and auxiliary components such as pigments, solvents, etc. and a second component comprising the polysiocyanate.

The reaction "curing" involves the secondary hydroxyl group of the resin and the isocyanate group of the polyisocyanate. However, due to the low reactivity between secondary hydroxyl groups and isocyanate, the ~ ring reaction proceeds relatively 810wly. Moreover, the isocyanate group also reacts with water and in some instances, such as on days of high humidity, that undesirable competing reaction may occur to such an extent 1 ~37~9 that the cure can be substandard (as evidenced, for example, by the resultant coating's poor resistance to solvent, especially where thin coatings or films are involved). It can be seen that prior coating compositions leave something ~to be desired as regards the coatings or films they are able to provide.
Statement of Invention It has now been found, and this finding forms the basis of the present invention, that the disadvantages occasioned by the slow curing of the resins in question can be reduced or even eliminated by introducing into the epoxy resin molecule, primary hydroxyl groups which react with the isocyanate groups of the polyisocyanate much more readily and rapidly compared with the indigenous secondary hydroxyl groups.
Moreover, and more importantly from a practical viewpoint, the introduction of such primary hydroxyl groups into the molecule of weather-stable diepoxides, which by reason of their sole epoxy or oxirane functionality would not normally be reactive with isocyanates, has been found to produce novel resinous polyols which are isocyanate -curable to produce weather resistant coatin~ compositions.
It is an object of the present invention to provide a modified DGEBA resin which, upon reaction with isocyanate is more rapidly cured than conventional DGEBA
resins.
It is a further object of the present invention to provide selected modified weather resistant diepoxide resins which are isocyanate c~rable and hence are utilizable in coating compositions capable of producing weather resistant coatings.

~ 1~37~

Detailed Statement of Invention The present invention provides a resin component for a coatins composition ccmprising a modified epoxy resin component and an isocyanate curing component, the resin component comprising the reaction product of a diol of formula:
HO-CH2- (R)a -CH2-OH
wherein R is a straight or branched chain alkylene group having at most 6, and preferably three, carbon atoms; or the cyclohexane group and a is O or l; and an epoxy ~elected from group (a) low molecular weight diglycidyl ethers of Bisphenol A ~DGEBA) epoxy resins characterized by the following formula A:

\ S -0~--C~O--CH2-c~-cH2- -O~C~--O--CH2-CH~-~H2 _ n wherein n is O or an integer from 1 to 2;

(b) diglycidyl ethers of hydrogenated Bisphenol A;

(c) 3, 4-Epoxy cyclohexylmethyl-3, 4-epoxy-cyclohexan carboxylate; and (d) vinyl cyclohexene dioxide.

The resinous polyol products are believed to have the following idealized formula B:

HO-CH2-(R) -CH2-O-CH2-CIH-CH2-O-R~-O-CH2-ClH-CH2-O-CH2-(R)a-CH2-OH

OH OH

wherein R and a are defined above; and Rl is the residue formed upon ring opening of 1 ~374~

both epoxide groups in the diepoxide resins of above groups (a), (b), (c) or (d), respectively.
For example, it is believed that the resinous polyols derived from the DGERA resins of (a) have the following idealized formula C:

CHg HO-CH-(R)a-CH2-O-cH2-clH-cH2- -O ~ -C ~ O-cH2-~H-cH2- _ CH3 OH CH3 ~ _ n -O ~ -CH ~ -O-CH2-CH-CH2-O-CH2-(R~ -CH2-OH

wherein R, a and n are defined above.
The term "idealized formula" is used to denote that, as a man skilled in the art i6 fully aware, it is not yenerally possible to characterize resins or the like by simple formulae and when it is possible to postulate such formulae to define a resin the formula will usually represent a "average" since in many instances the resin will comprise a mixture of resins.
A further consequence of this i9 the relatively inexact manner in which these types of substances, in particular those of groups (a) and (b), are defined although such definitions are well accepted in the art.
In a further aspect, the present invention provides a process for the production of said novel resinous polyol products comprising reacting the corresponding diepoxide of formula as defined above in (a), (b), (c) or (d) respectively, with at least 1.5 moles of a diol of formula:
HO-CH2- (R)a-CH2OH

1 1~37~

wherein R and a are defined above; il~ the presellce of a Lewis acid.
In yet a further aspect, the present invention provides a method of providing a substrate with ~ resistant coating comprising adrnixing a resinous polyol of formula B
above with a polyisocyanate; coating said substrate with the mixture so produced and allowing same to cure so as to form the desired coating.
With respect to the DGEBA resins of group (a), such resins where n > 2 contain very undesirable high molecular weight homologs, branched chain molecules and, probably, monoglycidyl ethers. On the other hand the lower molec-ular weight diepoxides wherein n < 2, and especially wherein n = O which are preferred, give, (i) reproducible results;
(ii) solutions having low viscosities; and tiii) give more accurate hydroxy equivalent weight calculations and, consequently are more convenient to use.
Turning to resins of group (b), specific examples thereof are the DRH151 series available from Shell Chemicals; resins of group (c) include the product available from Union Carbide Corporation under the trade designation ERL 4221; and resins of group (d), the product available from Union Carbide Corporation under the trade designation ERL 4206.
Products originatiny from the resins of groups (b), (c) and (d) are preferred on account of their advantageous resistance to weather and other adverse factors such as acids, etc.
Suitable diols include the following: straight chain diols; ethylene, propylene; butylene; pentylene;

,~ .~

I ~fi 374~

hexylene, heptylene, oxtylene, nonylene and decalene diols, as well as diethylene, dipropylene and other difunctional polyglycols; branched ehain diols include 2, 2-dimethyl propanediol; 2-methyl - 2-propane propanediol; 2-ethyl

-2-butyl propanediol; 3-methyl pentanediol and cyclohexane dimethanol.
Preferred Lewis acid catalysts include organic boron trifluoride complexes, especially boron trifluoride etherate, although others which may be used include for example, boron triamine salts (these compounds requiring dissociation using heat to become effective).
The polyisocyanates used in the curing of the resinous polyol may be aliphatic polyisocyanates such as those sold under the trade names Desmodent N by Bayer and Isophorone diisocyanate by Veba-Chemie, hydrogenated 4.4 diphenylmethane diisocyanate sold under the trade mark HYLENE W by Dupont or aromatic polyisocyanates such as toluene diisocyanate; xylylene diisocyanate; 4, 4-diphenylmethane diisocyanate as well as their NC0 functional adducts.
It has been found that the DGEBA-based resins of (a) where weather resistance is limited are preferably cured with aromatic polyisocyanates whereas those based on resins of groups (b), (c) and (d) preferably cured with aliphatic polyisocyanates.
The etherification reaction of the epoxy with the diol obviously results in the regeneration of a hydroxyl group. As unreacted epoxy may also react with such hydroxyl, the ratio of epoxy component: diol should be such so as to ensure there is an excess of primary hydroxyl groups over epoxy groups present at the start of the reaction if the production of highly undesirable excessively ~ 1~37 ~

higher molecular weight polymers is to be avoided. In practice, it has been found that 50% or more excess of primary hydroxyl over the epoxy is highly advantageous, the preferred epoxy/diol equivalent ratio being from 1.0/1.5-2Ø Alternatively, or in combination, a monofunctional compound, either a hydroxyl or epoxy, may be included in the reaction mix and function as a chain stopper to further suppress molecular weight build up. In general, any primary monohydric alcohol or monoepoxide will function as a chain stopper. Long chain alcohols of the general formula:
R" - CH20H

or long chain epoxides of the general formula Rl" - CH2 - CH -/ H2 o wherein R" is a hydrocarbon moietly containing C3 - C7 atoms and Rl" is an ether or ester moietly containing C4 - C12 atoms are preferred since apart from acting as chain stoppers, the long chain hydrocarbon portion of the molecule imparts improved solubility in aromatic hydrocarbon solvents to the resinous polyols.
The novel products are resinous polyols and a large series of such products, giving a wide range of various film properties upon being cured with isocyanates, can be prepared by utilizing a chain stopper as described above and/or varying the epoxy/hydroxyl equivalent ratio and/or the diol used. With respect to the latter, short chain low molecular weight diols have been found to give the best hardness in the cured film and excellent solvent ~ 1~3~9 resistance but poorest resin solubility and low tolerance for aromatic hydrocarbon diluents or solvents, the latter being economically a disadvantage.
On the other hand the use of a long chain monepoxide or monofunctional alcohol as a chain stopper improves resin solubility and aromatic hydrocarbon tolerance with, apparently, little effect on the speed of curing.
The choice of startiny diepoxide is very important and interalia determines the type and many of the characteristics of the film/coating which can be obtained on polyisocyanate curing: for example, the resinous polyols from diglycidyl ethers of 8isphenol A are rapidly cured with polyisocyanates to produce a variety of useful coating composition~ which give good chemical resistance coatings.
However, their utility as exterior coatings is limited since DGEBA-based resins in general have relatively poor exterior durability. On the other hand, the various diepoxides detailed in paragraphs (b), (c) and (d) on page 3 above, in general give coatings which are more durable relative to the DGEBA coatings and hence may be used to advantage in exterior applications.
The curing of the novel polyols with polyisocyanates maybe effected by processes well known in this art and detailed description thereof is deemed unnecessary. However, reference may be to standard works in this field, for example, ~he Federation Series on Coating Technology Unit 15 by David Lasovick, published by the Federation of Societies for Paint Technology, July, 1970.
The present invention will be further described, but not limited by, reference to the following specific examples. For convenience, all the specific examples relating to the DGEBA based products will precede those ~ 1637~
derived from other diepoxide resins. In the following E'rocedure, the specific reactants (and ratios thereof) are contained in the following Tables.
E'rocedure A

. .
All the components, apart from the catalyst, were added to a 3-necked flask fitted with a condensor, thermometer and agitator. Agitation was commenced and when a homogenous reaction mix was attained, 0.1~ Bf3 etherate, based on total reactants, were added as a 10~ solution of Bf3 etherate in ethoxyethyl acetate. The reaction is exothermic and the reaction mixture reached a temperature of from 90C to 200C the specific value in each instance depending on the diepoxide, total epoxy content and batch size. Upon completion of the reaction (when the exotherm ~eased) the resulting resin was allowed to cool and reduced with a ~olvent comprising a 50/50 volume mixture of xylol and ethoxyethyl actetate. Where the diol used was a solid or was incompatable with the e~oxy resin at room temperature, external heating was applied or a mutually compatable solvent (ethoxy-ethyl acetate) was added to facilitate compatability before the catalyst was added.
The specific details as to reactants, epoxide:
diol ratios, etc. used in the production of DGEBA based resinous polyols according to the presenL invention are given in Table I.

- ~0 T A B L E
r ~ D

H X ,_1 H H ~ ~ ~Y ~ H ~ ~
tY W O _ O' P- ~ g ~ O' ..
92B *Epon 1:4 None 1:2:0 141 Poor 828 Butanediol 97A Epon 1:4 None 1:1.5:0 161 P-Falr 828 ~utanediol 97A Epon 1:4 None 1:1.5:0 161 P-Falr 828 Butanedlol 100A Epon 1:4 Cardura** 1:2:0.5 195 Good-Excellent 828 Butanediol E 10 100A Epon 1:4 Cardura 1:2:0.5 195 Good-Excellent B.P. E 10 102A Epon 2.2 Dlmethyl None1:1.5:0 168 F-Good 828 1.3 Propanedlol 102A Epon 2.2 Dlmethyl None1:1.5:0 168 F-Good 828 1.3 Propanediol 104A Epon 1:4 N-Octanol 2:1:1 262 Excellent 828 Butanediol 105A Epon 1:4 N-Octanol 2:1.5: _ Gelled 828 ~utanedlol 0.5 llOA Epon 1:4 Cyclohexane None 1:2:0 160 Fair 828 Dimethanol 114A Epon 1:4 Cyclohexane None 1:1.5:0 198 Falr 828 Dimethanol 116A Epon 1:4 Cyclohexane N-Octanol 2:2:0.5 235 F-Good 828 Dlmethanol 117A tEpon None None 202 Good * DGEBA Epoxy Resins Manufactured by Shell Chemical-above formula where n ~ 0 **Glycidyl Ester of Versatic 10 Acld Manufactured by Shell Chemlcal t DGEBA Epoxy Reslns Manufactured by Shell Chemical-above formula where n ~ 2 The resinous polyols of Table I we~e converted to coatings or films on steel panels by curing in a manner known per se in the art with polyisocyanate. Details of the ~ ~37~9 polyisocyanate and isocyanate (NCO) hydroxyl (OH) ratios used as well as the properties of the resulting film or coating on steel panels, is contained in Table II.

T A B L E II

E~ _ ~ ~ ~_ o ~ ~ o W Vl o ~
z o g z ~¢ ~o ~ ~
.
92B *** Mondur CB 75 1:2 24 Hr~ Exc Soft 6 Rubbery, Exc Mar 97A n 1:2 24 Hrs Exc Rubbery & Tough 97A , 1:1 24 ~rs Exc Tough, Hard & Flexible 100A ., 1:2 24 Hr~ Exc Rubbery & Tough 100A - 1:1 24 Hrs Exc Tough, Hard & Flexlble 102A , 1:3 24 Hrs Exc Cheesy, Soft 102A - 1:1 24 Hrs Exc Tough ~ Hsrd 104A .. 1:2 24 Hrs V-Good Tough & Rubbery 110A - 1:2 24 Hrs Exc Tough, Hard & Plexible 114A .l 1:1 24 Hrs Exc Very Tough, Hard &
Flexible Xylol Resistant within 6 hours 116A ****Mondur MRS. 1:1 24 Hrs Exc Tough & Rubbery 117A Mondur CB 75 1:1 24 Hrs Poor Very Soft *** Proprietary Tolylene Dilsocyanate Polyol Adduct Manufactured by Mobay Chemical ****Polymethylene Polyphenyl Isocyanate Manufactured by Mobay Chemlcal It should be noted that Tables I and II also detail a control, namely resin code formula 117A. A
comparison of the results achieved with that formulation with those obtained with formulation 114A which had a 7 ~

similar hydroxyl equivalent weight and therefore sin;ilar NCO:OH ratio demonstrates the superiority of the present i.nvention involving the concept of inserting primary hydroxyl groups into the resin component. Formulation 114A
novel resinous polyol actually cured within six (6) hours to a solvent resistant state whereas the control DGEBA resin, cured with the same polyisocyanate, was still very tacky after the same six hours air drying time and did not develop solvent resistance until after forty-eight (48) hours had elapsed.

Procedure B
This method of producing the resinous polyols based on the more durable or resistant epoxy resins is exactly the same Procedure A with the exception that the temperature during the reaction ranged from 90C to a maximum of 150C.
Details of the epoxy resin, diol and chain stopper (if any) as well as the ratio of reactants and the novel resinous polyol procedure contained in Table III.

7 ~ ~

TABLE III

~ W ~ e X ~
z ~ z P ~o ~ oP ~
~ x ~ ~ ~ ~: ~ O ~;.
u) O O ~ D O ~ .C p.~ _ ,_1 o~ ~ ~ ~ ~ ~ ~. P~ C ~ ~
I _ ~ a ~ ~ ~ ~ o ~ X o 105B *DRH 151 1:4 ~utanedlol N-Octanol 1:1:0.25 250 Exc~
106A DRH 1511:4 Butanedlol **Cardura E10 1:2:0.5 225 Exc.
106A DRH 1511:4 Butanediol Cardura E10 1:2:0.5 225 Exc.
106A DRH 1511:4 Butanedlol Cardura E10 1:2:0.5 225 Exc.
109A DRH 151Cyclohexane 1.4 _ 1:1.5:0 228 Fair Dimethanol 10~A DRH 151Cyclohexane 1.4 _ 1:1.5:0 228 Fair Dlmethanol 111A DRH 151Cyclohexane 1.4 Cardura E10 1:1.5:0.25 270 Good Dimethanol 113B DRH 151 PCP-0200 _ 1:1.5:0 422 Exc.
Polycaprolactone A. 115A DRH 151 2.2.4 Trimethyl _ 1:2:0 190 Exc.
Pentanediol 1.3 121A t-ERL-4206 2.2 DimethylCardura E10 1:1.5:0.25 120 Very Good 1.3 Propanediol 122A tERL-4221 22. DimethylCardura E10 1:1.5:0.25 164 Poor 1.3 Propanedlol 126A DRH 151 Cyclohexane 1:4~**Epoxlde 7 1:1.5:0.25 266 Good Dimethanol A. Developed Small Gel ParticuLar During Reaction. Probably due to Secondary Hydroxyl *Diglycidyl ethers of hydrogenated Bisphenol A ~vailable from Shell Chemicals **Glycidyl ester of Versatic 10 Acid suppl1ed by Shell CheGlcal ***Aliphat~c glycidyl ether containing n-octyl and n-decyl alkyl groups: weight per epoxide 229. (Supplled by Proctor and Gamble.
~vinyl Cyclohexene dioxide ~3, 4-Epoxy cyclohexylmethyl-3, 4-epoxy-cyclohexan carboxylate Table IV contains details of the curing of the resinous polyols of Table III and properties of the films produced.

TABLE IV
_ ~ .

~ O H ~ 5' E~

O ~ :Z O ~ 1 ~ PC L
1~ ~ ~ O C:~ ~:: 0~ ~ ~
_ _ _ 105B *Desmodur N l:l O.l 24 Hrs Exc. Tou~sh & Rubbery 106A Desmodur N 1: 2 0~ 1 24 Hrs Fair Tacky Film 106A Desmodur N l:l O.l 24 Hrs Falr-Good Soft, Slight Tack, Poor Mar. Hardness 106A ***Isophorone l:l O.l 24 Hrs Falr-Good Soft, Sllght Tack, Dllsocyanate Poor Mar. Hardness lO9A Desmodur N l:l 0.1 24 Hrs Exc. Yery Tough ~ Hard, Exc. Mar. Hardness & Adheslon lO9A Desmodur N 1: 2 0.1 24 Hr~ Good-Exc R~ther Cheesy, Good Mar. Hardness 11lA Desmodur N l:l O.l 24 Hrs Very Good Tough & Hard, Exc. Mar. Hardness Rubbery ln Heavy l13B Desmodur N l:l 0.1 24 Hrs Good Soft, Cheesy, Slight Surface Tack 115A Desmodur N l:l 0.1 24 Hr~ Poor-Falr Soft, Cheesy, Poor Mar. Hardness 121A Desmodur N l:l O.l 24 Hrs Fair-Good Tough, Hard, Good Mar. aardness Good Adheslon 122A Desmodur N 1:1 0.1 24 Hrs Good Tough, Hard, Good Mar. Hardness Good Adheslon 126A Desmodur N l:l O.l 24 Hrs Good Good reslstance &
Ma_. reslstance _ . .
* Allphatlc Polyisocyanate Manufactured by Bayer.
***3 Isocyanato methyl 3.5-5 Trimethyl Cyclohexyl Manufactured by Veba-Chemie 7 4 ~

The present invention, therefore, produces a novel resinous polyol for use in two component epoxide/isocyanate chemical setting compositions. The novel polyols derived for DGEBA enable such compositions to set or cure to a practical hardness very rapidly compared with known compositions. Moreover, the polyols derived from the selected diepoxides of groups (b), (c) and (d) are isocyanate curable to provides resistant coatinss. Such compositions are described in detail herein with reference to their utility in the production of coatings on panels.
However, such compositions have other uses, for example, they may be used to advantage as adhesives, in reinforced glass fibre laminated, etc.

Claims (30)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A resin product for a two-component coating composition comprising an epoxide and a polyisocyanate curing agent, said resin product comprising a resinous polyol of the following idealized formula B:
wherein R is a straight or branched claim alkylene group having at most 6 carbon atoms; or the cyclohexane group;
a is 0 or 1; and R1 is the residue formed upon ring opening, with a diol of formula HO-CH2-(R)a-CH2-OH wherein R and a are defined above, of both epoxide groups in a diepoxide resin selected from the group consisting of:
(a) low molecular weight diglycidyl ethers of Bisphenol A (DGEBA) epoxy resins characterized by the following formula A:
wherein n is 0 or an integer from 1 to 2;

(b) diglycidyl ethers of hydrogenated Bisphenol A;

(c) 3, 4-Epoxy cyclohexylmethyl-3, 4-epoxy-cyclohexane carboxylate; and (d) vinyl cyclohexene dioxide.

2. A resin product for a two-component coating compsition comprising an epoxide and a polyisocyanate curing agent, said resin product comprising a resinous polyol of the following idealized formula C:
wherein R is a cyclohexane group or straight or branched chain alkylene group having at most 6 carbon atoms; n is 0 or an integer from 1 to 2; and a is 0

3. A resin product according to claim 2 wherein n = 0.

4. A resin product according to claim 1, 2 or 3 wherein a is 1 and R is a straight or branched chain alkylene group having at most three carbon atoms.

5. A resin product according to claim 1, 2 or 3 wherein R is the -(CH2)2- or group.

6. A resin product according to claim 1, 2 or 3 wherein R is the cyclohexane group.

7. A resin product according to claim 1, 2 or 3 in which said ring opening occurred in the presence of a chain stopper which is a monofunctional hydroxy or epoxy compound.

8. A resin product according to claim 1, 2 or 3 in which said ring opening occurred in the presence of a chain stopper which is a long chain primary monohydric alcohol of formula R" - CH2OH
or a long chain monoepoxide of formula wherein R" is a hydrocarbon moietly containing from 3 to 7 carbon atoms; and R''' is an ether or ester moietly containing from 4 to 12 carbon atoms.

9. A resin product for a two-component coating composition comprising an epoxide and a polyisocyanate curing agent, said resin comprising a resinous polyol of the following idealized formula B:
wherein R is the residue formed upon ring opening with a diol of formula:
HO-CH2- (R)a-CH2-OH
where R is a straight or branched chain alkylene group having at most 6 carbon atoms; or the cyclohexane group; and a is 0 or 1;

of both epoxide groups in a diepoxide resin which is diglycidyl ether of hydrogenated Bisphenol A.

10. A resin product according to claim 9 in which said ring opening occurred in the presence of a chain stopper which is a monofunctional hydroxy or epoxy compound.

11. A resin product according to claim 9 in which said ring opening occurred in the presence of a chain stopper which is a long chain primary monohydric alcohol of formula wherein R" is a hydrocarbon moietly containing from 3 to 7 carbon atoms; and R''' is an ether or esther moietly containing from 4 to 12 carbon atoms.

12. A resin product according to claim 9, 10 or 11 wherein a is 1 and R is a straight or branched chain alkylene group having at most three carbon atoms.

13. A resin product according to claim 9, 10 or 11 wherein a is 1 and R is the -(CH2)2- or group

14. A resin product according to claim 9, 10 or 11 wherein a is 1 and R is the cyclohexane group.

15. Process for the production of a resin product comprising reacting at least 1.5 moles of a diol of formula:
HO-CH2-(R)a-CH2-OH
wherein R is the cyclohexane group or a straight or branched chain alkylene group having at most 6 carbon atoms, and a is 0 or 1;
with one mole equivalent of an epoxide resin selected from the following group:
(a) low molecular weight diglycidyl ethers of Bisphenol A (DGEBA) epoxy resins characterized by the following formula A:
wherein n is 0 or an integer from 1 to 2;
(b) diglycidyl ethers of hydrogenated Bisphenal A;
(c) 3, 4-Epoxy cyclohexylmethyl-3, 4-epoxy-cyclohexane carboxylate; and (d) vinyl cyclohexene dioxide, in the presence of a Lewis acid.

16. Process for the production of a resin product comprising reacting at least 1.5 moles of a diol of formula:
HO-CH2-(R)2a-CH2-OH
wherein R is the cyclohexane group or a straight or branched chain alkylene group having at most 6 carbon atoms, and a is 0 or 1, with a molar equivalent of a diglycidyl ether of Bisphenol A
(DGERA) epoxy resin of formula A:

wherein n is 0;
in the presence of a Lewis acid.

17. Process for the production of a resin product comprising reacting at least 1.5 moles of a diol of formula:
HO-CH2- (R)a-CH2-OH
where R is the cyclohexane group; or a straight or branched chain alkylene group having at most 6 carbon atoms and a is 0 or 1, with a molar equivalent of a diglycidyl ether of hydrogenated Bisphenol A in the presence of a Lewis acid.

18. Process according to claim 15, 16 or 17 wherein the diol of formula HO-CH2-(R)a-CH2-OH a is 1 and R is the cyclohexane group.

19. Process according to claim 15, 16 or 17 wherein, in the diol of formula HO-CH2-(R)a-CH2-OH, a is 1 and R is the -(CH2)2- or group

20. Process as according to claim 15, 16 or 17 wherein the Lewis acid is an organic boron trifluoride complex.

21. Process according to claim 15, 16 or 17 wherein the Lewis acid is boron trifluoride etherate.

22. Process according to claim 15, 16 or 17 wherein the molar ratio of epoxide: primary hydroxyl is from 1.0:1.5-2Ø

23. Process according to claim 15, 16 or 17 in which a monofunctional hydroxyl or epoxy chain stopper compound is present.

24. Process according to claim 15, 16 or 17 in which a long chain primary monohydric alcohol of formula or a long chain monoepoxide of formula wherein R" is a hydrocarbon moietly containing from 3 to 7 carbon atoms; and R''' is an ether or ester moietly containing from 4 to 12 carbon atoms is present as a chain stopper.

25. Process according to claim 15, 16 or 17 in which a monofunctional hydroxy or epoxy chain stopper is present, the ratio of basic epoxide:
chain stopper being from 1:0.2 to 1:1.

26. Process according to claim 17 in which the molar ratio of basic epoxide : primary hydroxyl is from 1.0:1.5-20 and in which a long chain primary monohydric alcohol of formula:
R"-CH2OH
or a long chain monoepoxide of formulae:

wherein R" is a hydrocarbon moietly containing from 3 to 7 carbon atoms; and R''' is an ether or ester moietly containing from 4 to 12 carbon atoms; is present as a chain stopper, the ratio of basic epoxide:
chain stopper being from 1:0.2 to 1:1.

27. Process according to claim 26 wherein in the diol of formulae HO-CH2-(R)a-CH2-OH a is 1 and R is the cyclohexane group or the - (CH2)2- or group.

28. Process for the production of an resistant coating on a substrate comprising mixing a resinous polyol as defined in claim 1, 2 or 3 with a polyisocyanate, applying a coating of the resulting mixture to said substrate and allowing the so-formed coating to set.

29. Process for the production of a resistant coating on a substrate comprising mixing a resinour polyol as defined in claim 9, 10 or 11 with a polyisocyanate, applying a coating of the resulting mixture to said substrate and allowing the so formed coating to set.

30. Coated substrates whenever produced by a process as defined in claim 28 or 29.