CA1262594A - Hydroxyalkylcarbamate-containing self-cross-linking polymers - Google Patents

Abstract

29,463 HYDROXYALKYLCARBAMATE-CONTAINING
SELF-CROSS-LINKING POLYMERS
ABSTRACT
A self-cross-linkable polymer contains at least two hydroxyalkyl carbamate groups per molecule and may comprise the reaction product of a polymer, such as an epoxy or an acrylic resin, and at least one hydroxyalkyl carbamate-containing primary or secondary amine. Alternatively, the self-cross-linkable polymer may be obtained by polymer-ization of an ethylenically unsaturated, polymerizable mon-omer containing at least one hydroxyalkyl carbamate group.
The amine is joined to the monomer or to the backbone resin by reaction of primary or secondary amine groups thereof with suitable reactive functional groups of the resin.
method of making the polymer, which is heat curable to provide a thermoset film or coating, comprises reacting the monomer or the backbone polymer with an amine containing hydroxyalkyl carbamate groups or precursors thereof com-prising hydrolzable blocked primary amine groups. When present, the blocked groups are unblocked and reacted with a cyclic carbonate to form the hydroxyalkyl carbamate.

Description

i 463) BACKGROUND OF THE IMVENTION
The present invention concerns novel self-cross-linkable resins containing hydroxy-alkyl carbamate groups flnd methods of making the same.
The reaction of propylene carbonate with primary and secondary emines to producecorresponding 2-hydroxypropyl carbamates is known in the art (Comp. rend, 1142, 1954~.
Similar reactions of ethylene carbonate are exemplified by the article, "The Preparation of Polymeric and Cyclic Urethans and Ureas from Ethylene Carbonate and Amines" by Elizabeth Dyer and E~arvey Scott, J.A.C.S. (1956) pp. 672 - 675. See also the report "Polyurethane elastorners obtained without the use of diisocyanates" by L. Ya.
Rappoport, G.N. Petrov3 I.I. Trostyanskaya and O.P. Gavrilova in 1 Science and_Technology, 8~ No. 1, 1981. The Dyer-Scott reference discloses that polyurethanes might be prepared from 2-(hydroxyethyl)-carbamate by eIimination of ethylene glycol, thereby avoiding the need for using diisocyanates. The Rappoport et al paper dlscloses generally the reaction of cyclic carbonates with amines to form polyurethane elastomers. Thus, the prior art Shows an awareness that amines react with, e.g., propylene carbonate, to yield the corresponding hydroxyalkyl carbamates.
The Journal of Polymer Science, Vol. 7, 899 916 tl969), in an article entitled "New Method for Pree~ring Saturated and l~nsaturated Aliphatic Polyurethanes'' by Y. Mizake, S. Ozaki and Y. Hirata, at pages 899 - 915, discloses alternate routes to saturated and unsaturated polyurethanes, including polycondensation reaction of glycol bis(chlorofor-mate) with diamine.
An article by Richard D. Cowell entitledo "Thermoplastic Polyurethane Elastomers:
Chemistry Properties and Processing for the 80's'~ in the Journal of Elastomers and Plastics, Vol. 14, (October, 1982) pages 195 - 203, discloses the preparation of bis(2-hydroxyethyl) carbamates by reaction of diamines with ethylene carbonate followed by a catalyzed transesterification reaction with a glycol or macroglycol.

SUMMARY OF THE INVENTION
The present invention concerns self-cross-linkable polymers which contain at least two hydroxyalkyl carbamate groups per molecule and monomers which contain at least one hydroxyalkyl carbamate group and which are polymerizable to form the self-cross-linkable polymers. The polymers of the present invention are self-cross-linkable through their hydroxyalkyl carbamate groups when heated at an elevated temperature and preferably in the presence of a suitable cross-linking catalyst. The polymers may be ~2~i2~

obtained by reacting a suitable monomer or backbone polymer with an amine containing an hydroxyalkyl carbamate or precursor thereof. Preparation of the hydroxyalkyl carbamate-containing amine relies on the fact that multi-functional amines containing at least one primary and at least one hindered secondary amine group are, unexpectedly t selectively reactive with cyclic carbonates at the primary amine groupsl leaving one or more secondary amine groups unreacted in the resulting hydroxyalkyl carbamate. The resultant hydroxyalkyl carbamate contains at least one unreacted secondary amine group and may be reacted with any suitable backbone resin which contains appropriate reactive functional yroups to provide polymers which are self-cross-linkable through hydroxyal]cyl carbamate groups.
; ~n accordance with the present invention, there is provided a self-cross-linkable polymer containing at least two hydroxyalkyl carbamate groups per molecule, obtained by reaction of (a) secondary amine containing one or more hydroxyalkyl carbamate groups, with (b3 a reactant selected from the class consisting of (b)(i) monomers selected ~rom the group consisting of glycidyl methacrylate, glycidyl acrylate, isocyanatoethyl-methacrylate, maleic anhydride, methacryloyl chloride, n-methyloyl-acrylamide, l-(l-isocyanato-l-methylethyl)-3-(1-methylethenyl)-benzene, l-(l-isocyanato-l-methylethyl)-4~ methylethenyl~-benzene, methyl acrylamidoglycolate, methyl acrylamidoglycolate methyl ether, acryloyl chloride and chloromethyl styrene and (b) (ii) polymers comprising an epoxy resin selected from the group consisting of: (i) the reaction product of epichlorohydrin and a polyhydric phenol, (ii) the epoxy resin of (i) modified by : /~

' ':
`

~6~5~

reaction with carboxylate containing polybutadiene polymers, and (iii) the reaction product of epichlorGhydrin and a condensation product o~ phenol with acetone and ~ormaldehyde; wherein a cyclic carbonate is reacted with the amine groups to form the hydroxy-alkyl carbamate groups; and when said reactant comprises the monomers of (iii], polymerizing the resulting hydroxyalkyl carbamate-containing monomers.
Preferably, the polymers may have a molecular weight of from about 300 to about 100,000 and up to about 65% by weight of the polymer may be comprised of hydroxyalkyl carbamate groups.
Preferably the invention provides an ethylenically unsaturated polymerizable monomer containing at least one hydroxy-alkyl carbamate group. The monomer may be homopolymerized or copolymerized to provide -the above-described sel~-cross-linkable polymers.
In a preferred embodiment the monomers (b)(i) contain a polymerizable, ethylenically unsaturated moiety and an amine reactive site.
The present invention also provides a method of prepar-ing a self-cross-linkable polymer having at least two hydroxyalkyl carbamate groups per molecule comprises reacting (a) a secondary amine containing one or more hydroxyalkyl carbamate groups, with (b) a reactant selected ~rom the class consis~ing of ~b)(i) monomers selected from the group consisting o~ glycidyl methacrylate, glycidyl acrylate, isocyanatoethylmethacrylate, maleic anhydri.de, methacryloyl chloride, n~methyloylacrylamide, isocyanato-l-methylethyl)-3-(l-methylethenyl)ben7.ene, 1 isocyanato-l-methylethyl)-4~ methylethenyl)benzene, methyl - 3a -acrylamidoglycolate, methyl acrylamidoglycolate methyl ether, acryloyl chloride and chloromethyl styrene and (b)(ii) polymers comprising an epoxy resin selected Erom the group consisting of:
(i) the reaction product of epichlorohydrin and polyhydric phenol, (ii) the epoxy resin of (i) modified by reaction wit~ carboxylate containing polybutadiene polymers, and (iii~ the reaction product of epichlorohydrin and a condensation product of phenol with acetone and formaldehyde wherein a cyclic carbonate is reacted with the amine groups to form the hydroxyalkyl carbamate groups;
and when said reactant comprises the monomers of (iii), polymeriz-ing the resulting hydroxyalkyl carbamate-containing monomers.
Preferably the catalyst employed is a metal containing catalyst, especially a catalyst from the group consisting of tin, ; zinc and titanium compounds, especially dibutyltindilaurate. In another preferred embodiment the catalyst is selected from the class consisting of quaternary and ternary compounds~ for example, one or morequa~ernary ammonium, phosphorium or arsonium compounds and ternary sulfonium compounds. A quaternary ammonium compound is a particularly preferred catalyst.
Preferably the catalyst is present in an amount from about 0.1 to about 10~ by weight of the weight of polymer solids.
~nother aspect of the invention provides for utilizing monomers or polymers as described in the following detailed description, includin~ those having functional groups as described below, to prepare monomers and polymers containing groups as described a-t (a) through ~j) of the following detailed description of the in~ention.

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, : :

- 3b -61109~7361 Other aspects of the invention include applying a composition comprising the polymer of the invention and a suitable cross-linking catalyst onto a substrate and heating the coated substrate at a temperature and for a time sufficient to cure the applied composition. In one aspect, a low temperature cuxe in the presence of a cross-linking catalyst, at a temperature of from about 200 to about 250F (about 93 to about 121C) for a period of up to about one hour, for example, from about 20 to about 30 minutes, is provided.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Generally, hydroxyalkyl carbamate-containing amines which are reacted with suitable backbone resins to provide the polymers of the present invention are made by reacting one or more amines and cyclic carbonates to yield compounds having the formula:

(1) R-NH-C-O-CH-(C~)n~l~-OH
Rl R2 R3 wherein R is an organic moiety having at least one unreacted secondary amine group, each of Rl, R2 and R3 is independently H
or a Cl to C20 alkyl, cycloalkyl or alkyl aromatic moiety or any such moiety containing one or more heteroatoms, and n is 0 or 1.
R may also contain one or more heteroatoms. Such moieties containing one or more heteroatoms include, for example, those containing ether groups, thio groups and organo-silicon moieties.
The cyclic carbonate to be reacted with the multi-functional amine may comprise any suitable cyclic carbonate, including biscarbonates, which is reactive with one or more of f ~

-;
.
, 5~
- 3c -the primary amine groups of a multi-funetional amine. Generally, five-member ring organic carbonates are preferred as eompared to six-member ring organic carbonates, the latter being relatively more expensive and diffieult to prepare. Aecordingly/ a preferred cyelie earbonate utilizable in the present invention has the formula:

Rla Ib

(2) CH CH

\C/

o ';, wherein Ra and Rb may be the same or different, and each may comprise H, or a Clto C8 aliphatic, cycloaliphatic, aromatic or heterocyclic groups. Ethylene carbonate (dioxolane-2~ne), both Ra and Rb = H, and propylene carbonate (4-methyldioxolane-2-one), Ra = H and Rb ~ CH3, are preferred reactants.
The multi-functional amine utilized in the invention contairLs at least one secondary amine group which is hindered with respect to reacting with the cyclic car~onate and at least one primary amine group. As used herein and in the claims, (a) "multi-functional amine" means an amine containing Rt least one primary and at least one hindered secondary amine group; and (b) "hindered secondary amine group" means a secondary amine group which is inhibited, sterically, electronically or otherwise, with respect to reacting with the cyclic carbonate under conditions at which the primary amine group will react. It has been discovered that, surprisingly, the weU known reactivity of primary and secondary amines with cyclic carbonates is highly selective to the primary group for certain multi-functional amines. Stated otherwise, it has been found that certain multi-func tional amines have secondary arnine groups which are sterically or otherwise inhibited from reacting w;th a cyclic carbonate, and yet are reactive ~ith, for example, epoxy groups or other functional groups available on backbone polymers or on monomers which can be polymerized to provide such polymers as described elsewhere herein. Thus, hindered secondary amine groups contained in multi-functional amines utilizable in ae~cordance with the present invention enable the formation, with one or more cy~lic carbonates, of hydroxyalkyl carbamates in which secondary amine groups remain unreacted and available to react with epoxy or other active groups.
This enables the anchoring of hydroxyalkyl carbamate groups on the backbone polymer by reaction of the secondary amine groups with epoxy or other active groups on the backbone polymers. For example, when ethylene and propylene carbonates were reacted with diethylenetriamine, they reacted selectively with the primary amine groups of the triamine to form carbamate groups while leaving the secondary amine groups unreacted.
Such secondary amine groups can then be reacted with, for example, epoxy groups on backbone polymers, without affecting the carbamate groups. The resultant hydroxyalkyl carbamate-containing polymers of the invention can self-cross-link to yield thermoset polyurethanes suitable for a number of applications, for example, in the area of coatings.
The self-cross-linking reaction may be base catalyzed or tin-catalyzed, which offers significant advantages over prior amino resin systerns which require acid catalyzation.
Thus, the present invention enables the utilization of a system which is free offormaldehyde and in which cure inhibition in the presence of hindered amine ultraviolet stabilizers is avoided~

., ~5--The use of the hydroxyalkyl carbamate-containing amines to prepare the com-pounds of the present invention may be illustrated as foIlows. The hydroxyalkyl carbamat~-containing compounds may be reacted with one or more of any suitable backbone polymer or monomer containîng active groups, such as, for example, epoxy groups, in which case the reaction may be represented as

(3) R - LH - CH2 ~ HN / -- -~ Rh ; 2 ~F~;

where Rh is a fragment of an epoxy-containing resin or an ethylenically unsaturated monomer and Ri and Rj are fragments of the hydroxyalkyl carbamate~ontaining amine or polyamine compounds of the invention. The reaction usually occurs at room or slightly elevated temperatures and i~ often exothermic. The reaction may be performed without a solvent, otherwise aproti~ or alcohol solvents may be used. Any of numerous types of backbone polym ers having any of a variety of reactive functional groups thereon may also be used, as described in more detail below. For exarnple, a typical polymer having anchored thereon one or more of the compositions of the inventionmay have the formula O

(4) 11 - R~FHC~2N(~ H2CH2NHCCHCH2~)2) The resultant polymer, upon heating and, optionally, in the presence of a suitable cross-linking catalyst, will cross-link through one or mare mechanisms, flS follows:
by cross-linking through baclcbone hydroxyl groups, e.g., (S) CH
R - NH C - O - CH CH 2 OH ~ H O Rh .h c a t o CH
P~h-NHC-O-Rh ~ ~OCHCH20H;

I 1~

5~4 by cross-linking through self-condensation,e.g., O C~

(6) 2Rh-NHC-O-CHCH20H heat Rh-NH~ --fHCH2l NH-Rh ~ HOCHCH20H ; and by cross-linking through backbone amine groups~ e.g., Rh - NH~ - O - ~HCH2 OH ~ Rk - NH - Rh h e a t CH
NH~N-R h ~ HO~HCH~OH
~c wherein Rk is hydrogen or a fragment of the backbone polymer.
As indicated above, the polymers of the invention can be prepared by reacting either backbone polymers or monomers containing suitable functional groups with primary or secondary amines containing one or more hydroxyalkyl carbamate groups or precursors thereof. When monomers are thus employed, they are polymerized, after reaction with the amines, either by homopolymerixation or copolymerization with other monomers, to provide the polymers of the invention. As used herein, "suitable" functional groups simply means those functional groups, such as epoxy7 isocyanato, methylol, etc., which are reactive with the primary or secondary amine groups of the hydroxyalkyl carbamate-containing amines. For example, an hydroxyalkyl carbamate-containing monomer rray be prepared by reacting glycidyl methacrylate with an hydroxyalkyl carbamate-conWning secondary amine. The resulting monomer may then be homo- or co-polymerized to provide a polymer of the invention.
The repeating units of which the polymer is comprised may fall into two categories, one comprising units containing the suitabie amine-reactive functional groups and the other comprising modifying units selected to impart desired film-making or other properties to the polymer and the finished coating or other product made therefrom. Any suitabl~ repeating units may be employed in the polymer in any desired combination provided that there exist in the polymer sufficient suitable reactive functional~ groups for attachment thereto of the primary or secondary amines utilized in the reaction.
,:, 5~

In an alternate method of preparing the polymer of the invention, the monomers or backbone resins ~re reacted with amines which contain, in addition to one or mo~e secondary amine groups, hydrolyzable blocked primary amine groups, for example, ketimine groups in lieu of some or all of the hydroxyalkyl carbamate groups. After reaction of the secondary amine gr~ups with the reactive functional groups as described above, so that the amine groups are pendant upon the monomer or backbone resin, the hydrolyzable blocked primary amine groups are hydrolyzed to form free amine groups and one or more suitable cyclic carbonates, for example, are then added to the mixture to react with the resultant free amine groups. Thus, the multi-functional amine utilized to form the hydroxyalkyl carbamate will contain either an amine group reactable witll a cyclic carbonate or a hydrolyzable blocked primary amine group which is convertible to an amine group reactable with the cyclic carbonate.
The Multi-Function~l Amines A wide range of multi functional amines are utilizable in the present inYention to react with the cyclic carbonate inasmuch as, as stated above, it is necessary only that the multi-functional amine contain at least one primary and one hindered secondary amine. For example, one class of multi-functional amines utilizable in the present invention may be represented by the formula:

Rc~(NH-Rd)n2-NH-Re wherein n2 is O to 5, and each of Rc, Rd and Re is independently a straight chain or branched hydrocarbon fragment having 2 to 6 carbon atoms each and at least one of Rc and Re contains a primary amine group.
The formulas of suitable classes of amines may be derived simply by replacing with -NH2 the hydroxyalkyl carbamate moieties of the compounds set out in formulas ( 8) to (11) below.

( 8) H O - ~H - CH - O - ~- NH - ~ CH 2 ~ x ~ A ( CH ? ~ x N~

rein A is [NH (CH2)X] nNH, n is 0 to 10, each x is independently 2 to 6, preferably 2; each of Rl and R2 is independently H, or a Cl to C20 allcyl or alkyl aromaticmoiety, preferably, H or CH3. Preferably, n is not more than 10, more preferably, is from 0 to 6, most preferably from 0 to 4. Compositions in which x is 2 or 6 may readily be made from widely available r eactants, i.e., diethylenetriamine and dihexa-methylenetriamine and to that extent are preferred.
Another suitable class of compounds is represented by the formula:

(9) R3 NH- ( CH~ ~ NH - ~ - O CH - CH - OH
O Rl R2 wherein y is 2 or 3, each of Rl and R2 is as defined above, and R3 is a Cl to C20 alkyl, cycloalkyl or alkyl arornatic moiety, or any such moiety containing, in addition to at least one carbon atom, one or more heteroatoms. In this class of compounds, starting materials which would provide alkyl, cycloalkyl or alkyl aromatic moieties greater than C20 are not readily available. The Cl to C20 alkyl, cycloalkyl or alkyl aromatic moieties of all the formulas given herein, and somewhat shorter chains, i.e., Cl to C18 alkyl, cycloalkyl or alkyl aromatic moieties, are to that extent preferred.
Another class of suitable compounds is represented by the formula:
F
ll (10) ~ O Rl R2 ~6~r l~R4 ~7 il R5 wherein each of Rl and R2 is as defined above, each of R4 and R6 is independently H or a Cl to C4 alkyl moiety and each ~of R5 and R7 is independently a Cl to C4 alkyl moiety. Preferably, Rl and R2 are independently H or CH3 and each of R4, R~, R6 and R ;, is CH3.
Another suit~ble class of compounds in accordance with the invention has the f ormula:

5~A~
_9_ (11) H-~-NH-R8--NH~ O-fH~ H-~H
() Rl 112 H- -NH-R~3--N~ O ~H~H- OH
~1 ~2 NH--R8-NH-~-O-/~H--~H--OH
Rl 2 wherein each of Rl and R2 is as defined above and each R8 is independently a C2 to - C6 alkylene moiety, preferably -(CH2)2- or -(CH~)6-.
Monomers and Polymers Contai~unctional Groups Reactive with 5econdary Amines .
A wide variety of suitable monomers containing functional groups or sites which are reactive with primary or secondary amines may be employed to reaçt with the hydroxyalkyl carbamate~containing amines, to form the monomers containing hydroxy-alkyl carbamate groups. Such monomers include, by way of example and not limitation, glycidyl methacrylate, glycidyl acrylate, isocyanatoethylmethacrylate, maleic anhydride, methacryloyl chloride, n-methyloylacrylamide, l-(l-isocyanato -l- methylethyl) -3~
methylethenyl)benzene, l~l-isocyanato -1- methylethyl) -4- (l-methylethenyl)benzene, methyl acrylamidoglycolate, methyl acryl~midoglyco~ate methyl ether, acryloyl chloride and chloromethyl styrene. Thus, the reapeating units of the polymer may be derived from one or more of the foregoing monomers to provide one or more functional groups of the polymer as described below.
A wide variety of backbone polymers containing suitable functional groups may also be employed to react with the hydroxyalkyl carbamate-containing amines to provide the polymers of the invention. The choice of suitable monomers or polymers will depend on the characteristics desired for the finished coating or other product. Among suitable backbone poiymers are epoxy resins genera11y, including polybutadiene-modified epoxy resins, acrylic resins, polybutadiene resins and polyester resins.
In order to provide a site on the backbone resin or monomer on which the amines ma~ be ~nchored, each molecule of such b~ckbone resin or monorner should : ~ :
, :: ~

~ 5~ _ h~ at least one, and preferably more, reactive sites thereon which can react with the secondary ~mine group of the hydroxy~ yl carbamate-containing amine OI the invention. Such reactive sites may include, without limitation, one or more of the following ~roups:
(12) 0 (13) - CH X
~C-~ 2 (Acid halides, in which X (Halogenated Aliphatics, is a halogell, preferab~y in which ~ is a haloKen, Cl,Br or I~ preferably ~::1, Br .or I3 (14) (15~ 0 C C /\
~ C -G O-O O O
(alpha, beta unsatu.ated (Anhyd~ides) esters) (16) O (17) _ _ C' C~O
~C , NHCH2OH
~alpha,beta unsaturated ketones~ ( N Methylolamldes) (18) (19) I_ _ ~ CH2 0~ \ ' 0/
OH /
(Methylolated Phenols) ~Epoxies) (20) (21) - NC~
~lsocyanates) C

~ lethylol Carbamates) (22) -- S02~
( in which X is a halogen preferably Cl, sr or I) One suitable class of reactive sites on a monomer or polyrner is epoxy groups, for example9 suitable resins are acrylic resins with pendant glycidyl ether groups, epoxy resins derived by reaction of epichlorohydrin and bisphenol-A, or epoxy resins derived by reaction of epichlorohydrin with phenol formaldehyde resins. Ln addition9 polybuta-diene resins with pendant epoxy groups are also well suited to have hydroxyalkylcarbamate-containing amines anchored thereon to provide the cross-linkable polymer of the present invention.
Reaction of secondary amine groups of the hydroxyalkyl carbamate-containing amines with monomers or polymers containing funetional groups as illustrated at (123 - (22) above, will result in the formation of the following groups at the functional group sites.

(a) 1I cRq (f) --CHzN q (b) OH / Rq (g) --SO N ~ Rq --CH--CH2N r Rr (C) --N--C--N q (h)~CH2N-- q (d) o (i)~--C--CH--C~2N ~ q ~--C---NHCH2N q Rp ~Rr (e) O (i) ¦¦ ~ R
li R --O--C CH--CH2N q --CNHCH2N q I ~Rr Rr Rp wherein Rp is H or Cl - C8 alkyl; and Rq and Rr may be the same or different andal amine residues cont~ining hydroxyalkyl carbamate moieties.
The polymer containing functiona} group sites may also include modifying units as mentioned above and such modifying units may be derived from one or more of acrylic acid, methacrylie acid, butadiene, styrene, alpha-methyl styrene7 methyl metha-crylate~ butyl acrylate, acrylonitrile, hydroxyethyl acrylate, glycidyl m ethacrylate, acrylamide, methacrylamide, vinyl chloride and vinylidene chloride.

Epoxy Baekbone Resins Any suitable epoxide material may be utilizes3 as the backbone resin in accordance with the invention such as a monomeric or polymeric epoxy containing material, preferably a resinous polyepoxide material containing two or more epoxy groups per mclecule.
Among the known epoxides which have been found useful as backbone resins in the practice of the present invention are polyglycidyl ethers of polyphenols such as bisphenol-A or, generally, the reaction product of epi~hlorohydrin with a polyhydric phenol. As used herein, "polyhydric phenol" m eans and includes compounds such as bisphenol-A, bisphenol-F and bisphenol-S. Such epoxides may also be rnodified byreaction with carboxylate containing polybutadiene polymers or other modifying ma-terials.
Polyepoxides made from polyhydric phenol resins such as novalac resins or the like comprise one suitable class of compounds. Polyglycidyl esters of polycarboxylic acids, such as the reaction products of epichlorohydrin or other similar epoxy compounds wi~h reactants such as terephthalic acid~ glucaric acid, succinic acid, oxalic acid and the like may also be employed.
Multi-functional amines as described above may be reacted with, for example, a polyepoxide of one of the folIowing formulas:
CH
CH~--C~C:~3z [ Rg 3 n (~CH3 ~H~C~/ H~

where Rg is the repeating fragment CH Q~
--~ O~CH;~ CH-CH2 C1~3 -13 8l~59 and r~ is from O to 12, e.g., O to 2;

(b) ~n ~ ~H 2 oO O~l D Rl ~

where R' is a hydrogen or a methyl group ~nd Rlo is a- hydrogen atom or a glycidyl group and n2 is from O to 12;

(c) ORl L ~)R~ 1 --I~)Rl 1 (~ ' ~ . `' (~

H 3 C~CH 3 H 3 C--C--CH3 ~( H 2--~ -CH z--~

ORl 1 ORl 1 ~11 . _ ._ ~ 3 .
: (d) ORl 1 11 lRl 1 [~ , , $~H 2 H~jC~ 13 H3C--C--CH3 H3C--C-CH3 ~~C~32-~

ORll ORll n3 ORll wherein~ in (c) and (d), n3 is independently O to 4, ~nd R~} is a hydrogen atom or a glycidal group. In the claims, epoxides of the formula (c) or formula (d~, or mixtures thereof7 are referred to as an 1'aromatic novalac bisphenol-A resin". The defined term `

~ .
~, :
~ -', ~

-14- 3 ~
thl~- includes epoxides selected from the formula (c), or the formula (d3, or combinations thereof .
When it is desired that the polymer of the present invention have good water solubility/reducibility9 it is important to select backbone polymers that are OI low molecular ~equi~ralent) weight for monofunctional epoxides or of low equivalent weight for di- or polyfunctional epoxides. For high performance water soluble or reducible coatings, di- or polyfunctional epoxides are preferred. The use of such di- or polyfunctional epoxides allows for a high proportion of hydroxyallcyl carbamate groups to be incorporated into the epoxide, thereby providing a hydrophilic resin, e.g.~ one which is soluble or reducible in water. In addition to the epoxides described above, resins of the following formulas have been found to be well suited for the production of such w~ter soluble/reducible resins.

(e) tris (hydroxyphenyl) methane based resins of the formula:

RD.~)~ ,~ol H~H--CH~ G~

wherein, R = -CH2-CH- CH2, n is O to about 5 and preferably from about O to about 0.7, on average; and (f) triglycidyl isocyanurate polyepoxy resins of the general formula: -2 ~a/ Z c ~ 2 ~ ~Z

H2 c--Cb~Hz As used herein and in the claims, "tris (hydroxyphenyl) methane based resinl' means aresin of formula (e) above wherein n is O to S, and "triglycidyl isocyanurate polyepoxy resin" means a resin OI forrnula (f) above.
Ideally, all reactive epoxy groups will react with a secondary amine group to attach the amine to the epoxide and provide a substantially epoxy-free polymer.
However, this is less important for electrodepositable polymers wherein it is feasible to consume a small ex--ess of secondary amine groups by reacting the polymer with -15~ S~
loepoxides and to consume a small excess of epoxy groups by reacting the polymPrwith suitable amines.
Carboxylic acid-terminated polybutadienes may be reacted with epoxy resins to yield butadien~modified epoxy resins which may also be employed as backbone resins to prepare the polymers of this invention. Such butadiene-modified epoxy resins are described in SAMPE Quarterl~, Vol. 6, No. 4,1975.

crylic Backbone Resins Any suitable acrylic resin may be utilized as the backbone resin in accordance with the present invention. Any one of a variety of one or more monomers may be utilized to prepare an acrylic resin, and it is preferred that at least one of the monomers utilized contains at least one epoxy group. Such monomers include, by way of illustration and not limitation, styrene, substituted styrenes, alphamethyl styrene, alkyl acrylates such as butyl acrylate, butyl methacrylate, ethyl acrylate, 2-ethyl hexyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate1 acrylamide, methyl metha-crylate, acrylonitrile, glycidyl methacrylate, glycidyl acrylate, vinyl acetate, etc.
The backbone resir. may have other functional sites~ such as, for example, epoxy, hydroxy and arnide groups. It is preferred that the polymer of the invention, and hence the backbone resin, have as low an acid content as possible in or'der to facilitate low temperature cure of the polymer containing hydroxyalkyl, e.g., hydroxypropyl and/or hydroxyethyl, carbamate groups.
The Thermosettable Polvmers of the Invention _ . _ The polymers of the invention can be modified by reacting them with selected organic secondary amines (in addition to the hydroxyalkyl carbamate-containing amines) such as diethylamine, morpholine~ n-methylaniline, and the like. The selection and combination of specific modifying secondary amines of course depends on the end use of the polymer. For example, in the preparation of water-reducible polymers one or more hydrophilic secondary amines may be reacted with some of the functional sites on the backbone resin in order to enhance hvdrophilicity of the polym er. Conversely, for applications where hydrophobicity of the polymer is desired, for example, for electrodepositable coatings, it may be necessary or desirable to reQCt one or more hydrophobic secondary amines with the backbone resin to impart the desired degree of hydrophobicity to the polymer. Genera11y, the polymers of the invention are well suited for utilization in the field of coatings and in such case have molecular weights in the range of from about 300 to about lOO,OOO. The urethane cross-linkable polymers of the invention are particularly well suited for a variety of uses in the field of ,~ .

~. . ~ . ~, ... ....

;

.

16 ~ 5~
c ings, such RS solvent or water based coatings, powder coatings, electrocostingcompositions, spray roller and dip type coatings, and the like. Such coatings are normally applied to a substrate such as a metal, text91e9 plastic or paper. The thermosetting resins of the invention may be used to prepare urethane coatings which are organic solvent, abrasion ~nd water resistant3 as well as adhesives ~nd laminating resins.
The preparation of the hydroxyalkyl carbamate-containing secondary amines, which sre to be reacted with suitable backbone resins or monomers to obtain the polymers of the invention, is illustrated by Examples 1 - 39 following.

EgAAlPLE 1 Diethylenetriarnine in the amount of 206 grams (2 moles) and 600 grams of solvent methanol were added to a suitable reactor. 612 grams (6 moles) of propylene carbonate, which amount comprises 2 moles in excess of the stoichiometric amount, was slowly added to the reactor under a nitrogen blanket while the temperature of the reactants was maintained at 15 to 20 C by ice bath cooling. After complete addition, the mixture was stirred 8 hours at room temperature. Methanol was thenremoved by use of water purnp vacuum and with steam bath heating. The resulting product solution comprised diethylenetriamine bishydroxypropyl carbamate and was 73~6 solids in propylene carbonate ~theory 7596 solids), had 2.16 me~/g secondary amine (theory 2.37 meq/g at 7396 solids), and gave characteristic bands in the infrared for the hydroxypropyl carbamate groups.

Ea~AMPLE 2 .~2 To a suitable reactor containing 103 grams (1 mole) of diethylenetriamine and 300 grams of solvent methanol under a nitrogen atmosphere 184.8 grams ~2.1 moles) of ethylene carbonate was slowly added. The temperature was maintained at 15 to 20C
by ice bath cooling. After complete addition, the mixture was stirred at room temperature overnight. Methanol was then removed by use of a water pump vacuum and with steam bath he~ting. The resulting product solidified to a mass of whitecrystais upon cooling, mp 82 to 88~C. Recrystallization from ethanol afforded a pure product, mp 96 to 97 C, in nearly quantitative yield. The product gave cornpletely consistant IR and NMR spectra for the bis-hydroxyethyl carbamate of diethylenetriamine, i.e., diethylenetriamine bis-hydroxyethyl carbamate.

E~AMPL~ 3 -Diethylenetriamine in the amount of 206 grams (2 moles) was added to a suitable reactor equipped with an inlet for a nitrogen atmosphere and with a decanting trap ir `le distillate return line. The reactor was cooled in an ice bath and propylene carbonate (306 grams, 3 moles) was slowly added with good stirring, while maintaining the temperature below 40 C. Upon complete addition, the reactor was heated and stirred at 80C for 2 hours after which time no unreacted propylene carbonate could be detected by infrared ~nalysis. To the reactor was then added 300 grams (3 moles) of m ethyl isobutyl ketone (MIBK) and the contents were brought to reflux. Afterrefluxing approximately two hours9 the theoretical amount of water was collected in the decanting trap and the reactor was cooled. The resulting product comprising a mixed carbamate/ketimine of diethylenetriamine was 73% solids in MIBK ~theory 74.8%
solids). Non-aqueous potentiometric l:itration for secondary amine disclosed 2.58 meq/g amine (theory for 73% solids is 2~46 meq/g) and the infrared showed the characteristic bands for hydroxypropyl carbamate and ketimine groups~

The following two examples illustrate the preparation of hydroxyalkyl carbsmate-containing monomers, which are to be polymerized to form the hydroxyalkyl carbamate-containing polymers of the invention.

E2~MPLE 3A
To 24 grams of 1,2~imethoxyethane were added 7.1 grams of glycidyl methacrylate and 13.7 grams OI the hydroxyalkyl carbamate of Example 2. The reaction mixture was heated to 85C for four hours and 1,2-dimethoxyethane was removed by distillation under reduced pressure. The resulting water white product was viscous and glassy and contained 0.3 millimols per gram of free residuaI epoxy groups. The mass spectrum showed a major peak corresponding to the mass of the desired product of the following structure:

O OH
C}12= C--C--O--CHz--CH--CH2N ( CH2CH2NHCOCH2 CHzOH) 2 CH

.
To a suspension of 27.9 grams of the hydroxyalkyl carbamate of Example 2 in 100 grams of t-butanol was added 20.8 grams of 1- (l-isocyanato -1- methylethyl)-3~1-methylethenyl3benzene. The reaction mixture was stirred with a high speed stirrer.
Most of the solids dissolved after 2 hours and I.R. showed a small amount of unreacted ~18~ 4 i~ Janate. The reaction mixture was stirred overnight, then filtered to remove trace amount of insolubles, and t~but~nol was distilled from the filtrate under reduced pressure. The N.M.R. of the resulting product showed it to be of the following structure:
CH~ jCH2 C

C--NHCN (CH2cH2NHcOcH2cH2oH) 2 The following two examples illustrate polymerization of the hydroxyAlkyl carba-mat~containing monomers of Examples 3A and 3B to provide polymers in accordance with the invention.

E:gAMPLE 3A-l To a suitable 3 neck flask equipped with stirrer and a thermometer are added SO grams of 2-ethoxyethanol. At reflux temperature, a blend of 60 grams of N-butylacrylate, 20 grams of styrene, 59 grams of the monom~r of Example 3A., l gram of N-dodecyl mercaptan and 2 grams of dicumyl peroxide in 50 grams of 2-ethoxyethanol is added to the flask over a period of 2 hours. The reaction mixture is held at 145C
for 2 hours. The resulting resin of 58~6 solids h~ 8 basic nitrogen content of 1 meq per gram of resin solids, and an hydroxyethyl carbamate content of 2 meq per gram of resin solids.

EgAMPLE 3~1 To a suitable 3 neck flask equipped with a sti.rer and a thermometer are added 175 grams of toluene. At reflux temperature a blend of monomers comprising 58.g grams of N-butylacrylate, 45 grams of methyl methacrylate, and 71.2 grams of thehydroxypropyl carbamate~ontaining monomer of Example 3B is added to the toluene along with 4 grams of ~ t-butylperbenzoate as the initiator. After 4 hours at reflux a resin containing hydroxypropyl carbamate groups is obtained. The resin comprises 5096 solids and contains 1.65 meq hydroxypropyl carbamate per gram of resin solids.

A catalyst may be used to promote cross-linking of the polymer of the invention.The catalyst may be an external catnlyst or it may be incorporated as an internal catal~st during preparation of the backbone resin, as Is known in the artO For example, .
...

_19~ 5~
ql ~rnary ammonium hydroxide groups may be incorporated into the backbone resin.Any suitable cross-linking catalyst may be utilized, such as known metal~ontaining catalysts such as the known tin, zinc7 and titanium compounds or ternary or quaternary compounds as described below. Ben~yltrimethyl ammonium hydroxide, dibutyltindi-laurate, and similar compounds are good catalysts for achieving cross-linking at elevated temperatures in the range of from about 100 to about X7S~ C (about 212 to about 347F) for a period o a few seconds to about 30 minutes. A catalyst may be present in a formulation in the amount of from ~bout 0.1 to about 10% by weight of the polymer, preferably~ from about 1 to about 5% by weight of the polymer.
The ternary or quaternary catalysts are known compounds of the formula:

I P
Rr-- S -- R X and RS-- M --Rq X, respectively, q R

where Rp, Rq, Rr and Rs may be equivalent or different and may be Cl to C20 aliphatic, aromatic, benzylic, cyclic aliphatic and the like, where M may be nitrogen, phosphorlls or arsenic (to provide, respectively, quaternary ammonium, phosphonium or arsonium compounds), where S is sulfur (to provide a ternary sulfonium compound) and where X may be hydroxide, alkoxide, bicarbonate~ carbonate, formate, acetate, lactate, and other carboxylates derived from volatile organic carboxylic acids or the like. Such salts of carboxylic acids are effective to promote the low temperature cure provided that the carboxylic acid portions of the salt are volatile.
Strong bases such as alkali metal hydroxides (KOH, NaOH, I.iOH, etc.) may 1so beused as the cross-linking catalysts.

The following exarnples illustrate the preparation and utilization of specific compositions in accordance with the present invention.

Examples 4 - 7 illustrate the preparation and use of water-based coating compositions in accordance with the present invention.

E~AMPLE 4 A. A self-cross-linking bisphenol-A hydroxypropyl carbamate-containing resin which can be reduced with water to at least 15?6 solids as a clear solution with only , 2~ by total composition weight of cosolvents was prepared from the following ingredi ents:

Parts by Wei~h ~ lents Solids EPON 828~ 150.9 0.82 150.
~i Carbamat~containing Amine of Example 1 380.0 0.82 277.4 ~5hell Chemical Co. reaction product of epichlorohydrin and BP-A
The EPON 828 and the carbamate-containing amine of Example 1 were added to a suitable reactor under nitrogen equipped with a Cowels high speed stirrer. Upon stirring, the temperature was allowed to reach 100C (heat of exotherm) and was then maintained at this temperature by external cooling for one hour. After this, themixture was stilTed and heated at 70 C for 4 hours more. The fin~l produc~ had a solids content of 8096.
B. A sprayable aqueous composition was made up by mixing 191.4 parts of the resin obtained in part A of this Example with 191.4 parts of deionized water and 15.3 parts of ethylene glycol monobutyl ether cosolvent. The resulting clear solutioncontained only 13.5~6 by total weight organic cosolvents and was 38.596 solids. To this solution was added 14.5 parts of aqueous 1 Molar tetrabutyl ammonium hyclroxide catalyst and the contents were well stirred. This composition was applied, by spraying, to aluminum panels. The panels were baked at 250F (121 C) for 20 minutes and- showed film thickness of 0.3 to 0.4 mil after cure. The coatings were smooth, glos~sy, had 4H pencil hardness, passed 4Q in~lb reverse impact, and resisted greater than 300 water and methyl ethyl ketone (MEK~ double rubs.
E~AMPLE 5 A. A self-cross-linkable novalac hydroxypropyl carbamate resin which can be reduced with water to at least 12~6 solids as a clear solution with 20~6 by tot 1 weight of cosolvent was prep~red from the following ingredients:

~ Parts by ~Veight Eauivalents Solids EPN 1139* 128.3 0.75 128.3 Carbamate-containing Amine of Example 1 347.3 0.75 253.5 *Ciba Geigy Co. reaction product of phenol-formaldehyde condensate with epichloro-hydrin The EPN 1139 and carbamate-containing amine of Example l were reacted in the same manner as described in Example 4, controlling the exotherm by external cooling when necessary. The final product had a solids content of 80%.
~ T~fQC~

B. A sprayable aqueous composition was prepared by dissolving 100 parts of the novalac-hydroxypropyl carbamate-containing resin of part A of this Example in 100 parts of deionized water and 15.4 parts of 1 Molar tetrabutyl ammonium hydroxidecatalyst. The resulting clear solution contained only 9% organic cosolvent and was 39% solids. Aluminum panels were sprayed and then baked at 250F for 20 minutes~The resulting cured coatings were 0.5 0.6 mil thick, had 4H pencil hardness, passed 40 in-lb reverse impact, were smooth and glossy, and resisted greater than 300 MEK and wa~er double rubs.

E~AMPLE 6 A. A self~ross-linking bisphenol-A hydroxyethyl carbamate-containing resin which can be reduced with water to at least 10% solids as a clear solution with 20~6 by total weight o cosolvent was prepared from the following ingredients:

Parts by Weight Equivalents Solids EPO~ 82~ 85.7 0.466 85.7 Carbamate-containing Amine of Example 2 130.0 0.468 130.0 Butyl Cellosolve* ~ 53.9 -- 0.0 ~Monobutyl ether of ethylene glycol The EPON 828, carbamate-containing amine of Example 2, and butyl Cellosolve weremixed and reacted as in Example 4. The final product had a solids content of 80%.
B. A composition for spray application was prepared by dissolving 100 parts of the BP-A hydroxyethyl carbamate of part A of this Example in 100 parts of deionized water and 7.7 parts of 1 Molar tetrabutyl ammonium hydroxide catalyst. The resulting clear solution contained only 10~6 organic cosolvent and was 39~6 solids~ After spraying aluminum panels and then baking at 250F for 20 minutes, the film thicknesses were 0.3-0.4 milO The coa~ings were smooth and glossy, had 4H pencil hardness, passed 40 in-lb reverse impact, and resisted greater than 300 MEK and water double rubs.

~AMPLE 7 A. A self-cross-linking saturated hydroxyethyl carbamate~containing resin which can be reduced to at least 20?6 solids with 20a'o by total weight cosolvent was prepared from the following ingredients:

Parts by Weight EquivalentsSolids Eponex DRH 151* 100.0 0.42 100.0 Carbamate-containing Amine of Example 2 112.0 0.40 112.0 ~Eponex DRH 151 - Shell Chemical Co. Hydrogenated BP-A epichlorohydrin product ~ /~eee /~

5~4 The Eponex DRH 151 and carbamate-containing amine of Example 2 were reacted in the same manner as described in Example 4, carefully controlling the exotherm with external cooling when necessary. The final produet was 100~6 solids. This product was reduced to 80% solids with ethylene glycol monobutyl ether.
B. A sprayable composition WRS prepared by mixing 100 parts of the saturated hydroxyethyl carbamate of Part A of this Example with 100 parts of deionized water and 15.4 parts of 1 Molar tetrabutyl ammonium hydroxide catalyst. The resulting clear soluticn at 399~ solids and containing 9% organic cosolvents was sprayed onto aluminum pflnels. The psnels were cured at 270F for 20 minutes and afforded film thicknesses of 0.4 to 0.5 miL The coatings were smooth, glossy, had 3~I pencil hardness, passed 40 in-lb reverse impact and resisted greater than 200 MEK rubs and 300 water rubs.

The foIlowing Examples 8 and 9 illustrate the preparation and use of cathodic electro-coating compositions in accordance with the present invention.

E~AMPLE 8 A. A self-cross-linking cathodic electrocoating composition containing tertiary amine groups was prepared from the following ingredients:

~Wei~ht Equivalents Epon 1004~ 1017.0 1.0 Methyl isobutyl ketone (MIBK) 176.0 Carbamate-containing Amine of Example 1 370.4 0.8 Diethylamine 15.0 0.2 Propasol P** 150.0 ~A trademark of Shell Chemical Co. for its product comprising the reaction product of epichlorohydrin and bisphenol-A
**A trademark of IJnion Carbide Corp. for its propoxypropanol product B. The Epon 1004 and MIBK were charged under nitrogen to a suitable reactor as described in Example 2. (The same type reactor is used in Examples 5-9.) The mi~ture was heated to reflux with stirring in order to remove an~ water present.After cooling to 80 C the carbamate-containing amine of Example 1 was added andthe temperature was allowed to rise to 90C (mild heat of e~otherm). Upon complete addition the mixture was heated and held at 100 C for 2 hours. The diethylaminedissolYed in Propasol P was then added slowly so as not to lose diethylamine by volatilization. After addition, the mixture was heated further for 2 hours at 85 C.
To remove residual free amine~ 250 parts of Proposal P was added and then this same -23~ 5~
a. ~unt was removed by vacuum distillation at 110 to 125 C. The resultant product comprised 7696 by weight resin solids and 0.79 meq amine per gram based on 100%
resin solids.
C. An electrodeposition bath was prepared by combining 50 grams of th~
self~ross-linkable cathodic electrocoating resin obtained in part B of this Example with 10 gr~ms of hexyl Cellosolve (ethylene glycol monohexyl ether - a Qowing agent)7 1.2 grams of 89.9% formic acid, and 1.3 grams of dibutyltindilaurate (a urethanecatalystl. 398 grams of deionized water was slowly added while rapidly mixing with a Cowels stirrer to produce a bath containing approximately 10% solids. The resultant electrodeposition bath had a pH of 4.69 a conductivity of 18G0 micromho crn 1, and a rupture voltage of 180 volts.
D. The b~th composition obtained in part C of this Example w~ applied, by electrodeposition, to aluminum panels serving as the cathode at 75~J for 20 seconds t deposit a thin resin coating on the panels. The panels were then baked at 175C for 20 minutes and showed film builds of roughly 0.2 - 0.4 mils. All were slightly rough because of minor gassing during electrodeposition as a consequence of emulsion conduc-tivity. This problem could readily be overcome by refining the preparation technique to remove residual free amine. All panels exhibited 4H pencil hardness and resisted greater than 200 methyl ethyl ketone double rubs.

EgAMPLE 9.
A. A self~ross-linkable cathodic electrocoating composition containing tertiary amine groups is prepared from the following ingredients:

~ Equivalents EPON 1004E* 780.0 l.00 MIBK 176.0 Carbamate-containing Amine of Example 3 302.0 0.78 Propasol P** 105.0 EPON 1001F* 96.8 0.20 Diethylamine 32.0 0.44 *A trademark of SheU Chemical Co. for its product comprising the reaction product of epichlorohydrin and bisphenol-A
*~A trademark of Union Carbide Corp. for its propoxypropanol product B. The EPON 1004F and MIBK were charged under nitrogen and water was removed flS in Example 4. At 80 C the carbamate-containirlg amine of Example 3 was added followed by the EPON 1001F and one-half of the Propasol P. The mixturewas stirred and held at 80C for two hours and then the diethylamine dissolved in the ,,,t .

-24~ 5~
r aining Propasol P was slowly added so as to prevent volatilizationO The mixture was then stirred and heated at 85C for 8 hours. 150 grarns of Propasol P was then added and rernoved by vacuum distillation (flask temperature 110 to 120 C). This process was repeated with another 150 grams of Propasol P. The resultant producteomprised 7696 by weight resin solids and 0.91 meq amine per gram; based on 10096 resin solids.
C. An electrodeposition bath was prepared by combining 50 grams of the self~ross-linkable cathodic electrocoating resin obt~ined in part B of this Example with 5 grams of hexyl Cellosolve, 5 grams of benzyl hydroxypropyl carbamate (a reactive diluent-flow agent prepared by reacting one equivalent OI benzylamine with one equivalent of prowlene carbonate and removing any residual amine with acidicion-exchange resin); 10 grams of EPON 828 (Shell Chemical Co.), 1.54 grams of 89.9%
forrnic acid, and 1.63 grams of dibutyltindiIaurate. 376 grams OI deionized water was then slowly added while rapidly mixing with a Cowels stirrer to produce a bath containing approximately 1296 solids.
D. The bath composition obtained in part C of this Example was applied, by electrodeposition~ to aluminum panels serving as the cathode at 75V for 20 seconqs to deposit fl thin resin coating on the panels. The panels were then baked at 175C for 20 minutes and afforded film builds of 0.4 mils. The coatings were smooth, flexible, had 4H pencil hardness, passed 40 in-lb impact tests, and resisted greater than 200 methyl ethyl ketone double rubs.

Example 10 illustrates the preparation of an acrylic-urethane coating in accor-dance with the present Invention.

E~AMPLE 1O
A. An acrylic-urethane polymer is prepared as follows. 100 grams 2-ethoxyethanolwas added to a 3-neck flask suitably equipped with stirrer, thermometer, and a condenser and hea~ed to 135C. Over a two hour period, a blend of 60 grams of n-butyl acrylate, 20 grams of styrene, 20 grams of glycidyl methacrylate, 2 grams of dicumyl peroxide, and 1 gram of n~odecyl mercaptan was added to the heated 2-ethoxyethanol. After the complete addition of the monomer blend containing an initiator and a chain transfer agent, the reaction temperature was held at 140 C for two hours. Throughout thepolymerization reaction a nitrogen blanket was maintained in the reactor. The resultant resin had solids content of 47% and epoxy content of 0.64 meq per gram.
B. To the acrylic resin obtained in part A of this Example was added 36 grams (0.13 mole) of bishydroxyethyl carbamate derivative of diethylenetriamine (the hydroxy-alkyl carbamate of Example 2) and the mixture was heated to 80 C for two hours and then to 120 C for two hours. The resulting resin had the following characteristics.
Solids: 56.5%, Viscosity: U-V, Gardner Color: 5-6, Basic Nitrogen Content: 0.51 meq per gram and Epoxy Content: less than 0.05 meq per gram.
Four clear coating formulations were prepared by blending the polymet of Example 10 with various catalysts as shown in Table I. These coating formulations were cast on zinc phosphate pretreated cold rolled steel panels and cured 2t elevated temperatures. The cure conditions and film properties are shown in Table L The results in Table D[ show that the polymer of Example 10 self-~ross-links at temperatures QS low as 125C in 20 rninutes. Tin catalyzed cross-linked acrylic-urethane films show good humidity and salt spray resistance. All the self-cross-linked films show excellent resistance to methyl ethyl ketone double rubs. Use of a hydrophobic quaternary catalyst such as methyltricaprylyl ammonium hydroxide results in self-cross-linked films which are better in humidity and salt spray resistance than those obtained from the formulation containing a hydrophilic quaternary benzyltrimethyl ammonium hydroxide.

Table I

Parts by Wei~t Formulation: I 11I~ IV
Contents ___ The Polymer of Example 1010 10 15 23 Dibutyltindilaurate 0.1 -- --~enzyltrimethylammonium -- 0.2-- --nydroxide (4096 in methanol) Tetrabutyldiacetoxy -- -- 0.2 stannoxane Methyltricaprylylammonium-- -- -- 0.7 hydroxide (72~6) T~ble ~
Formulation I I D: ~[
Cure Schedule 175C 150C 122C 150C
~0 min. 20 min. 20 min. 20 min.
Film Thickness 31 25 25 28 (micr~meters) Knoop Hardness 13.7 6.6 7.4 7.1 Pencil Hardness H-2H F-H H-2H H-2H
Impact (Reverse inO lbs.) 30-40 60 80 80 MEK Rub Resistance I00+ 100+ 100+ 100+
Humidity . 21 days 21 days 2-3 2-3 Resistance (65 C~ hours hours Salt Spray Resistance 200 hours 200 hours Less Less than than 8 hrs 8 hrs Formulation m III IV I~
Cure Schedule 122 C 150 C 125 C 1509 C
60 min. 20 min. 20 min. 20 min.
Film Thickness 22 22 38 33 (micro-meters) Knoop Ha~ dness 3.9 7.3 7.1 8.3 Pencil Hardness F-H H-2H F-H F-H
Impact (Reverse in. lbs.) 60 G0 30-40 20-30 MEK Rub Resistance 100+ 100+ lG0+ lOû+
Humidity RFsistance (65 C) - - 24 hours 3 days S~lt Spray Resistance - - 60 hours 60 hours no corro- no corr~
sion. Loss sion. Loss of adhe- of adhe-sion at sion at scribe scribe .
:, .

--27~

A clear elec~ocoating system was prepared by emulsification of 70 grams of the polymer of Example 10 with deionized water in the presence of 1 gram of dibutyltindilaurate catalyst and 11 grams of acetic acid, to 10% solids. The pH and conductivity of the 1096 solids electrocoating emulsion were 4.8 and 175 micromho cm 1 respectively. Zinc phosphate pretreated cold rolled steel panels were electrocoated at 100 volts for 30 seconds and later rinsed with deionized water. The electrocoated panels were cured at 150 C and 175 C, respectively, for 20 minutes. The resulting films had good organic solvent resistance and good hardness as shown below.

Film P~erties of Electrocoa_ed Films of Part A of this Example Cure Schedule 150 C, 20 min. 175 C, 20 min.
Film Thickness ~micrometers) 17.5 22.5 Knoop Hardness 5.8 9.3 MEK Rubs 200~ 200~
Impact (Rev) in-lbs. 40 30-40 Salt Spray Resistance8;5 mm 8;3 mm (120 hrs.) (ASTM D610-68) Generally, the polymers of the invention may be applied in any suitable way to a substrate and may be heat-cured. By utilization of a suitable cross-linking catalyst as described above, heat curing may be attained at temperatures from about 200 to about 400 F (about 93 to about 205 C). The applied composition may comprise the polymer, a suitable catalyst and a liquid vehicle, such as an aqueous or organic solvent vehicle.

Although the foregoing examples are directed to the reaction of resins with secondary amines containing hydroxyalkyl carbamate (or precursor) groups, primary amines containing such carbamate or precursor groups may also be so employed, as -28~ 5~4 pr iously stated. However, it will be recogniæed by those skilled in the art that primary amines can act ~s difunctionPI reactive sites so that ge11ation of the reaction mixture may occur with certain classes of amine-reactive functional groups such ns, for example, epoxides, allylic or benzylic halides, or functional groups which invol~Je Mannich or Michaels type reactions. Therefore, secondary amines are a preferred class of reactants. However, one of ordinary skill in the art c~n readily determine by the simple expedient of a conventional ge~lation test whether a specific composition of reactants will be suitable for the desired spplication.
Generally, reference herein and in the claims to hydroxyaLlcyl carbamates and compounds containing the same, including structural formulas of the sarne, is intended to include the various isomeric species thereof, if any.
While the imention has been described in detail with respect to specific preferred embodiments7 it will be app~rent to one skilled in the art that numerous v~riations may be made to the embodiments without departing from the spirit and scope of the invention.

Claims (23)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A self-cross-linkable polymer containing at least two hydroxyalkyl carbamate groups per molecule, obtained by reaction of (a) secondary amine containing one or more hydroxyalkyl car-bamate groups, with (b) a reactant selected from the class con-sisting of (b) (i) monomers selected from the group consisting of glycidyl methacrylate, glycidyl acrylate, isocyanatoethylmeth-acrylate, maleic anhydride, methacryloyl chloride, n-methyloyl-acrylamide, 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)ben-zene, 1-(1-isocyanato-1-methylethyl)-4-(1-methylethenyl)benzene, methyl acrylamidoglycolate, methyl acrylamidoglycolate methyl ether, acryloyl chloride and chloromethyl styrene and (b)(ii) polymers comprising an epoxy resin selected from the group consisting of:
(i) the reaction product of epichlorohydrin and a polyhydric phenol, (ii) the epoxy resin of (i) modified by reaction with carboxylate containing polybutadiene polymers, and (iii) the reaction product of epichlorohydrin and a condensation product of phenol with acetone and formaldehyde; wherein a cyclic carbonate is reacted with the amine groups to form the hydroxyalkyl carbamate groups; and when said reactant comprises the monomers of (iii), polymerizing the resulting hydroxyalkyl carbamate-containing monomers.

2. The polymer of claim 1 wherein the monomers of (b) (i) are copolymerized with different monomers.

3. The polymer of claim 1 wherein the monomers of (b)(i) are homopolymerized.

4. The polymer of claim 1 wherein the monomers (b)(i) con-tain a polymerizable, ethylenically unsaturated moiety and an amine-reactive site.

5. The polymer of claim 1 having a molecular weight of from about 300 to about 100,000.

6. The polymer of claim 1 wherein up to about 65% by weight of said polymer is comprised of hydroxyalkyl carbamate groups.

7. A polymer comprising a polymeric backbone structure to which is joined at least two pendant groups selected from the class containing of:

(a) (f) (b) (g) (c) (h) (d) (i) (e) (j) wherein Rp is H or C1 - C8 alkyl; and Rq and Rr may be the same or different and are amine residues containing hydroxyalkyl car-bamate moieties, wherein said polymeric backbone includes modify-ing units derived from one or more of acrylic acid, methacrylic acid, butadiene, styrene, alpha-methyl styrene, methyl methacryl-ate, butyl acrylate, acrylonitrile, hydroxyethyl acrylate, glycidyl methacrylate, acrylamide, methacrylamide, vinyl chloride and vinyl-idene chloride.

8. A method of preparing a self-cross-linkable polymer having at least two hydroxyalkyl carbamate groups per molecule comprises reacting (a) a secondary amine containing one or more hydroxyalkyl carbamate groups, with (b) a reactant selected from the class con-sisting of (b)(i) monomers selected from the group consisting of glycidyl methacrylate, glycidyl acrylate, isocyanatoethylmethacryl-ate, maleic anhydride, methacryloyl chloride, n-methyloylacrylamide, 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)benzene, 1-(1-isocyanato-1-methylethyl)-4-(1-methylethenyl)benzene, methyl acryl-amidoglycolate, methyl acrylamidoglycolate methyl ether, acryloyl chloride and chloromethyl styrene and (b)(ii) polymers com-prising an epoxy resin selected from the group consisting of:
(i) the reaction product of epichlorohydrin and a polyhydric phenol, (ii) the epoxy resin of (i) modified by reaction with carboxylate containing polybutadiene polymers, and (iii) the reaction product of epichlorohydrin and a condensation product of phenol with acetone and formaldehyde wherein a cyclic carbonate is reacted with the amine groups to form the hydroxyalkyl carbam-ate groups; and when said reactant comprises the monomers of (iii), polymerizing the resulting hydroxyalkyl carbamate-containing monomers.

9. The method of claim 8 wherein the monomers of (b)(i) are copolymerized with different monomers.

10. The method of claim 8 wherein the monomers of (b)(i) are homopolymerized.

11. The method of claim 8 wherein the monomers (b)(i) contain a polymerizable, ethylenically unsaturated moiety and an amine-reactive site.

12. The polymer of claim 1 wherein the reactant (b) is a polymer of (b)(ii) comprising an epoxide selected from the group consisting of:

where Rg is the repeating fragment and n1 is from 0 to 12;
(b) where R' is a hydrogen or a methyl group and R10 is a hydrogen atom or a glycidyl group and n2 is from 0 to 12;
(c) an aromatic novalac bisphenol-A resin;
(d) a tris (hydroxyphenyl) methane based resin; and (e) a triglycidyl isocyanurate resin.

13. The polymer of claim 1 wherein the amine is an hydroxy-alkyl carbamate-containing amine selected from the group consist-ing of:
(i) wherein A is [NH (CH2)x]n; n is 0 to 10; each x is independently :
2 to 6; each of R1 and R2 is independently H, or a C1 to C20 alkyl cycloalkyl or alkyl aromatic moiety or any of the foregoing containing one or more heteroatoms in addition to at leaast one carbon atom;

(ii) wherein y is 2 or 3; each of R1 and R2 is as defined above; and R3 is a C1 to C20 alkyl, cycloalkyl or alkyl aromatic moiety or any of the foregoing containing one or more heteroatoms;
(iii) wherein each of R4 and R6 is independently H or a C1 to C4 alkyl moiety and each of R6 and R7 is independently a C1 to C4 alkyl moiety or such moiety containing one or more heteroatoms in addition to at least one carbon atom; and (iv) wherein each of R1 and R2 are as defined above and each R8 is independently a C2 to C6 alkylene moiety.

14. A method of preparing a cross-linked material from the polymer of claim 1 comprises applying a composition com-prising the polymer and a suitable cross-linking catalyst onto a substrate and heating the coated substrate at a temperature and for a time sufficient to cure the applied composition,

15. The method of claim 14 wherein the coated substrate is heated at a temperature of from about 200 to about 250°F
(from about 93 to about 121°C).

16. The method of claim 14 wherein said cross-linking catalyst is a metal-containing catalyst.

17. The method of claim 14 wherein said metal-containing catalyst is selected from the group consisting of tin, zinc and titanium compounds.

18. The method of claim 14 wherein said catalyst is dibutyl-tindilaurate.

19. The method of claim 14 wherein said catalyst is selected from the class consisting of quaternary and ternary compounds.

20, The method of claim 14 wherein said catalyst is selected from the class consisting of one or more of quaternary ammonium, phosphonium and arsonium compounds and ternary sulfonium compounds.

21. The method of claim 14 wherein the catalyst is a quaternary ammonium compound.

22. The method of claim 14 wherein the coated substrate is heated to a temperature of from about 200 to about 250°F (from about 93 to about 121°C) to cure the applied polymer,

23. The method of claim 14 wherein said catalyst is pre-sent in the amount of from about 0.1 to about 10% by weight of the weight of polymer solids.