CA1090040A - Radiation curable coating composition and method for preparation of the same - Google Patents

Abstract

Abstract of the Disclosure 3-Halo-2-hydroxypropyl acrylates and methacrylates and 2-halo-1-(hydroxymethyl)ethyl acrylates and methacrylates are used as reactive solvent for an acrylic or (meth)acrylic terminated polyether resin in radiation curable coating compositions. Mixtures of the (meth)acrylic terminated polyether resin and 3-halo-2-hydroxypropyl (meth)acrylate and/or 2-halo-1-(hydroxymethyl)-ethyl (meth)acrylate are usually prepared by adding diglyeidyl ether of bisphenol A to (meth)acrylic acid while the weight of 3-halo-2-hydroxypropyl (meth)acrylate and 2-halo-1-(hydroxymethyl)ethyl (meth)acrylic in the reaction mixture 18 at least about 5 percent by weight of the sum of the weights of the (meth)acrylic terminated polyether resin, the 3-halo-2-hydroxypropyl (meth)acrylate and the 2-halo-1-(hydroxymethyl)ethyl (meth)acrylate present in the reaction mixture. In a preferred embodiment, both epihalohydrin and diglyeidyl ether of bisphenol A are added to the (meth)acrylic acid.

Description

r', , !r. .:
~. . .
;''' ' .
r'` ''' "' ~
:~. .:;',:

,r",.,,~
'.,' .~r ' .'' ''.~'~-.`",.
a3~o~0 ~' ~ ,: ,,~.`, , .
..
`.
. ~ ., .
"

.: , ~: .:
.. . ...
.:.
, ~ . '~', .
' ~` ::

:~... .
I i . ., ,r~
. , .":
.;,"~",~ .
''~''`'''''"'' .-...................................... Disclosure ~s-' ~`.- Resin represented by the formula:
~;:

, -. .- ,~
.'''',', _ _ r ~ CH~2~H Cll3 Cl~l3 (C 2)bH
~ ~ ~H2 C~QcH2lL~CH20 - ~ f ~ oCIl2C~LCH2- ~ ~ 0CH2CHCLL20C ~CH2 OH C1~3 OH . C113 HO

~::- n ,, ., ~. ~ ., ~ .3 .,~, , .: ..i ;' ~y~
~,: .................................................................... . .

:

wherein the average value of n is in the range of from U to 3 and ~herein the average values of a and b ~re each independently in the range of from O to 1, ; ~ is an excellent material for use as the principal cross]inkable film-forming '~ component of radiation curable coating compositions. Desirable properties :.:
~ ~ such as hardness, mar resistance, abrasion resistance, stain resistance, .-' toughness and durability may be imparted to radiation cured films by this ., resin. It responds quickly to exposure to ionizing radiation or actinic light to produce cured coatings having these properties. When exposed to ,,;
~!;'". ultraviolet light, excellent surface cures ~ay be obtained in air as wellr~ . as in a substantially oxygen-free atmosphere because the degree of oxygen inhibition to curing is relativelv low under these conditions.
. . .
Unfortunately, the viscosity of the resin is rather high and, . in most cases, is too great for convenient application without dilution ..;'-by one or more solvents. Inert volatile solvents such as methyl ethyl ~- ketone, ethyl acetate, xylene, toluene, acetone, 2-metiloxyethanol, ethanol and propanol provide satisfactory thinning, but their use is undesirable `j l because additional equipment with its a~tendant expense is often necessary - to remove the solvent from the film ~ithin a reasonable time and to confine pollution by solvent vapor within to].erable limits~
. . .
Reactive solvents have been used in an effort to eliminate or markedly reduce the need for removal of solvent from the film~ However, ,.,:,;
many reactive solvents such as styrene, vinyl toluene, divinyl benzene, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, ethyl nlethacrylate? propyl methacrylate, butyl methacrylate and 2-ethylehxyl acrylate have s~lch high volatilities that atmospheric pollution is sti:ll a ma~or problem~ Usually as the molecular weight of reactive solvent is increased in an effort to reduce volatility? the viscosi-ties of the solvent and the coating composition of which it is a part are -: .!
increased. The reactivity is also generally reduced by increasing the molecular weight. ~pon exposure to ultraviolet light, the curing of many of these reactive .`:''';~

- 2 -~ ., ,; .
..

:
,;,.,i ' 109~0~o .-. solvents is inhibited by oxygen~ ~eactive`solvents such as 2-hydroxyethyl :- : acrylate and 2-hydroxypropyl acrylate which have acceptable volatilities :.;:
~i and viscosities, unfortunately possess unacceptably high toxicities.
-;-- The present invention provides reactive solvents having lower . . .
toxicities than 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate, low '`r,"',-, volatilities and low viscosities and which are suitable for diluting acrylic . .:
..` functional polyether resins of the type heretofore described. Accordingly, ::~ .
~ .` the present invention contemplates a radiation curable coating composition ,., . : having a binder comprising resin represented by the formula:
~;

H2)aH CH3 CH3 (CH2)bH
CH2=~COC~i2CHCH20 ~ OCH2CHCH20¦ ~ C ~ )--OCH2CHCH20fl=CH2 ~" O Oll CH3 H CH3 H O (I) ~:
i- n '..'''.
dissolved in reactive solvent represented by the formula:
:.
," :~ ' (IH2)cH (ICH20)fH
~ CH2= H - CH _ CIH ~ CH2CldBre (II) O OH
. :.,:, .
~:i wherein ~,:
.;. the average value of n is in the range of from a to 3;
the average values of a, b and c are each ~ndepende~tly in the range ; of from O tq l;
. ;-~, i , ~ . the aVerage value of d is in the range o~ from 0 to 1;

i",~
~ the aVerage value of e i$ in the range of from 0 to 1;
~.? `~ ' : : d ~ e = l;
, ,~; the average value o f is in the range of from O to l;
;- the average value of ~ is in the range of from O to l; and : . i f ~ g = 1~

-;

. ~., i, , . ~ ,,, . : , , ~ , .
: , ~;`; .
109~D0~
,. .
... .
When the value of a is zero, the ~(CH2~ H group is hydrogen. When the value of a is one? the group is methyl. In an analogous manner, the similar groups containing b and c are either hydrogen or methyl, depending upon whether ,...:-,~; ~
~ the values of b and c are zero or one~ ~lthough the values of a, b and c will ~,.: ,:
each independently be either zero or one for any particular compound, the ` average values of these quantities for mixtures of compounds may be whole or :xi~ fractional numbers in the range of from O to 1. The values of a? b and c may be determined analytically or, as is most often the case, by a knowledge ~'"t,''.' of the structures of the starting materials used to prepare the compounds.
:.~ ,:~:
: The values of a and b may be different for any particular compound, but it is preferred that they be the same. Often they are both one, but it ,:: ., ~
is especially preferred that they both be zero in any particular compound.

The resin may be a mixture of compounds wherein the average values of a .~ and b are different, but it is preferred that the average values of a and 1 ~ ' `
b be the same. ~Isually~ the average values of both a and b are zero or one.
It is particularly preferred that the average values of both a and b be zero.
Similarly, the reactive solvent may be a mixture of compounds wherein the values of c for the individual compounds constituting the mixture are different, but it is preferred that these values be the same, in which case the average value of c for the mixture will be zero or one.
It is particularly preferred that the average value of c for the reactive solvent be zero.

é -:,, The yalue of n ~or any particular compound will be zero or a positive integer, while the average~alue of n for a mixhlre of compounds constituting the resin may be a ~hole X ~actional numbex. The value of _ for indivldual compounds may~be 0, li 2, 3, 4 or e~en higher. Usually, the value of n for individual compounds is ~, 1 or 2. ~ilen the ave~age alues of a and b are known, the average value of n for the resin may be calculated from the number average molecular weight~ The number .~,................................ .
` ;r~
'~

~.'';.~', ~; - 4 -., .
,~'"; , ~ ,: ' . , .

~ 109~0~
:~ average molecular weight. The numl?er average molecular weight may be folmd experimentally or calculated from the distrlbution of individual compounds, lf this is known, using the equalities:
,;~,. .:
.:
_ ~M.N ~w ,,'.' Mn ~Ni 1 where M is tlle number average molecular weight;
Mi is the molecular weight of molecules of species i;
Ni is the number of molecules of species i;
Wi is the mass, expressed in grams, of molecules of species i; and -`` mi is the mass, expressed in gram-moles, of molecules of species i.
:: ~
~ The average value of n for the resin is in the range oE Erom O to 3. Typically, i~ it is in the range of from O to about 2. More often, the average value of n is , . .~ . .
i ~ in the range oE from O to about 1.

- The values of d and e in the product may vary, depending upon whether ` epichlorohydrin, epibromohydrin or mixtures of epichlorol~ydrin and epibromohydrin --i are used in preparing the reactive solvent. The values of d and e for any `~ particular compound will be either O or 1. When the value of d is one, the :~ value of e for the compound will be zero. Likewise, when the value of d is .s~ zero, the value of e for the compound will be unity. For mixtures of compounds, ~ the average values of d and e may be whole or fractional numbers such that d ~ e =

,~ Usually, tl~e average value of d for the mixture is either zero or one and the `~ average value of e is, respectively, either one or zero. It is preferred that !''' ,, `.~ the average value of d for the mixture be one and the average value of e be zero.
~- The epihalohydrin, wllether epichlorohydrin, epibromohydrill or mixtures of epi-chlorohydrin and epibromohydrin, used in preparing tl-e reactive solvent may be r~presented by the formula:
c\l~cllc~l2cldBr (IV) ~' ' O
where the values of d and e are as discussed above. Usually, the average values of d and e for the epillalollydrin are the same or substnlltially the same as those ~ ~ for the reactive solvent.
.~ . .
. . ~ , ~ _ 5 -~; -,.
., .. . .
~' ' ' ' . . . .
~ .. ~ .: . . . .
. '',.~:: . ' .: . . . ..

19~ 4 ~
The values of f and g for any particular cnm1~ounc1 will be eitherO or l. When the value of f is one, the value oE ~ for the compound will be zero. Likewise, wl1en the value of f is zero, the value of g for the compound will be one. For mixtures oE compounds, the average values of f ~..
r~, and ~ may be whole or fractional numbers such that f ~ len the reactive solvent is prepared by reacting epihalohyclri11 w:itl1 acrylic acid andlor metllacrylic acid, the values of f and g for a coml)ou1ld w:Lll be c1etermined by which bond of the epoxide group is attacked during the reaction. The : . .
- average values of f and g for the mixture of compo~mds resulting from the reaction will be determined by the distribution oE the epoxide bonds attacked.
.. Usually the average value of g for 8UCll mixtures :is greater than the average ~; value of f. For most purposes, it is not necessary to analyze mixtures of these compounds for the average values of f and g, it being satLsfactory to utili~e the mixture as formed by the reaction. Nevertt1eless, it is permissible, .~
?`~`~ and sometimes desirable, to modify the average values of f and g by adding appropriate amounts of specific compounds having structures wlthin generic Formula II. Similar]y, mixtures of compounds having appropriate values of c, d, e, f and ~ may be formed by admixing compounds having the structures within generic Formula II.
- From a consideration of the permissible values of c, d, e, f and g, ~ compound species within generic Formula II are:
!-

3-chloro-2-hydroxypropyl acrylate 3-chloro-2-hydroxypropyl methacrylate ~.',~`.'; !,, . 3-bromo-2-hydroxypropyl acrylate 3-bromo-2-hydroxypropyl methacrylate 2-chloro-l-(hydroxymethyl)et11yl acrylate 2-chloro-1-(hydroxymethyl)rtllyl methacrylate 2-bromo-l-(hyc1roxymethyl)ethy] acrylate '....:
, 2-bromo-l-(hydroxymethyl)etl1yl methacrylate The reactive solyent may comprise only one of these compounds or it may ;r;` comprise mixtures oE more than one. The preferred compounds are 3-chloro-2-hydroxypropyl acrylate and 3-bromo-2-hydroxypropyl acrylate. The former is especially preferred.
,. ~ "
:` .
. ~. . .

~. . .

;:
10~004~
.
The proportions of resin and reactive solvent present in radiation `` curable coating compositions may vary widely. Usually, the amount of resin present is in the range of from about 5 percent to abont 95 percent by weight of the binder. ~ore often, it i5 in the range of from about 10 percent to ~- about 80 percent by weight of the bincler~ An amount in the range oE from - about 15 to about 70 percent is preferred~ The amount of reactive solvent . . .
` present is usually in the range of from about 5 to about 9S percent by weight - of the binder. An amount in the range of from about 20 percent to about 90 percent is typical~ An amount in the range of from about 30 to about 85 percent by weight of the binder is preferred. secause the reactive solvent eventually becomes an integral part of the cured coating, it is considered to be a part of the binder.
' A resin represented by the ~ormula: -;,~.................................................... .
~:c: _ _ .,.

;.r'` ( f 2)a ICH3 CH3 (fH2)b~
':', CH2=C~OCH2~HCH2o--(~--C ~--CH2f~CH2 ~ oCH21HC11201CIC=CH2 H 3 OH H3 ~l O

n (I) ; dissolved in a reactive solvent represented by the formula:
, .
"" (,CH22CH (C~H20)fH
" CH2=cclo Cl ~'~CH2CldBre g wherein the reactive solvent constltutes from about 5 percent to about 95 percent by weight of the m~xture a~d t~e values of a through g are as described above has been found to be particularly u~e~u~ i~ tl~e binder of radiation curable coating compositions.

; ' :' .. .
:: . .

.,"
. . .
:: . . - . . .
~; ' . . " ,:
.... . .

r --~
.:
~ "".
,;
)9CllO~L~
'~ ;'.-J The resin may be prepared by reacting the diglycidyl ether of bisphenol A with acrylic acid, methacrylic acid or mixtures of these acids.
The preparation is described in British~Patent Speciflcation No. 1,006,S87.
. -:
- Several batches oE resin may be blended together when desired.
Compounds constituting ~he reactive solvent may be prepared by re- -~ ....... ..
- acting acrylic acid, methacrylic acid or mixtures of acrylic acid and meth-,` acrylic acid with epichlorohydrin, ep~bromohydrin or mixtures oE epichloro-hydrin and epibromohydrin. ~he reaction is usually conducted at an elevated temperature most often in the range of $rom about 50C. to about 120C~
stabilizer such as hydroquinone or 2,6-di-tert-butyl-4-methylphenol is usually present to inhibit free radical polymerization during the reaction~
he reaction may be conducted with or without a solvent.
. - . . .
; A solution comprising the resin dissolved in the reactive solvent ~:~r may be prepared in several ways~ One method is by simply admixing the resin and the reactive solvent. Another is by reacting bisphenol A-diglycidyl .:,.
ether with acrylic and/or methacrylic acid in the presence of reactive solvent~ Still another is by reacting epihalohydrin with acrylic and/or methacrylic acid in the presence of the resin. The preferred method is by reacting a mixture of bisphenol ~-diglycidyl ether and epihalohydrin with acrylic and/or methacrylic acid~ ~
As mentioned, one manner of p~eparing the solution has been to admix the resin and the reactive solvent. However, separate preparation of these materials re~uires elther two separ~te reactors or the~ ~andem use of one reactor. ~oreover, during prepa~ratio~ o$ the resin, the viscosity increases, o~ten reaching high va~ues, If a~itation is inade~uate, h~ating is localized in the ~îscous re~ctio~ mixture ~which Qfte~ causes undesirable polymerization of the resin, vlz., gelling~ ~.lso, i$ ethylenically unsaturated monocarboxylic acid is added to the diglycidyl ether of bisphenol ~, there is a substantial tendency of the epoxy groups of the diglycid~l ether of bisphenol ~ to themselves polymerize to form higher molecular weight polyetllers due to catalysis by the acid. ~

, i, . .
~ . - 8 -~;:, .
., ~ . .
: ' ' :, , i~:

According to the present invention, in the preparation of a mixture of the resin and the reactive solvent, both being oE the types hereinbefore described, wherein the reacti~e solvent constitutes ~rom about , 5 percent to about 95 percent by weight of the mixture and wherein diglycidyl : - ether of bisphenol A represented b~ the ~ormula: -r~ ~jNCHzO~ ~OCHz~HCHzO~ --~OCH2C CHz (1111 c H3 H H3 ' ?.
'`:;:' j:., where the average value of n is in the range of from O to 3, is reacted with ethylenically unsaturated monocarboxylic acid which is acrylic acid, meth-acrylic acid or mixtures of acrylic acid and methacrylic acid, the present improvement is adding the diglycidyl ether of bisphenol A to the ethylenically unsaturated monocarboxylic acid while the weight of reactive solvent in the reaction mixture is at least 5 percent of the sum of the weights of the resin and the reactive solvent present in the reaction mixture. The presence of at ..~, ~, .
least 5 percent reactive solvent, based on the sum of the weights of reactive solvent and resin in the reaction mixture~permits maintenance of the viscosity of the reaction mixture at acceptably low values during formation of the resin.

i~i -~ Since the reactive solvent is a component of the binder of the ultimate product, ,~ vi~i., radiation curable coating composition~ there is ordinarily no need to remove reactive solvent ~rom t~e reaction mixture. ~oreoyer, inasmuch as di-glycidyl ether of bisphenol A is added to ethylenically ~nsaturated mQnocar-`,. ~, :.
boxylic acid, the concentration o~ epoxy groups i5 so low tha~ reaction With ; ~ the acid to ~ornl the desi~ed re5in predomi~ates over the ~desired side react:ion.
.~. , ;:,~:;.,:~
"~
.. "
., ,.~ ~

",.~ . ,.
,, .
"~; _ g _ ~;; ., .
.':
,,; ,:, . ~, , . ... ... __ ;.':. ~
.~,:~ . . . :

~ `:
` -~,,, 1 -~, It is preferred that both epihalohydrin and diglycidyl ether of , .
bisphenol ~ are added to the ethylenically unsaturated monocarboxylic acid.
The product ma~ be preparecl according to any of several embodi~ents.
According to one embodiment, a mixture o$ reactive solvent and ethylenically unsaturated monocarboxylic acid i$ formed by admixing 3-halo-2-hydroxypropyl acrylate and ethylenically unsa~urated monocarboxylic acid~ ~he reactive solvent may be added to the acid~ the acid may be added to the solvent or they may both be added concurrently. Diglycidyl ether of bisphenol A is then added to the mixture of reactive solvent and acid to form the product.
According to another embodiment, a mixture of reactive solvent and ethylenically unsaturated monocarboxylic acid is formed by reacting epihalohydrin with ethylenically unsaturated monocarboxylic acid to form the reactive solvent. A mixture of reactive solvent and ethylenically unsaturated monocarboxylic acid is then formed to which is added diglycidyl ether of bisphenol A to form the product, as described in the first embodiment.
According to another embodiment, a mixture of reactive solvent and ethylenically unsaturated monocarboxylic acid is prepared by admixing epihalo-hydrin with an excess of ethylenically unsaturated monocarboxylic acid. The acid may be added to the epihalohydrin, the epihalohydrin may be added to the acid, or they may both be added concurrently. The product is then formed by adding diglycidyl ether of bisphenol A to the mixture.
According to another embodiment, diglycidyl ether of bisphenol A
and epihalohydrin a~e concu~ren~ly~addeid as separa,te stxea~s to the ethyleni-cally unsaturated monocarboxylic acid to produce the product.

According to the preferred e~bodiment, the product is prepared by adding a mixture of diglycidyl ether of bisphenol A and epihalohydrin to the ethylenically ~nsaturated monocarboxy;lic acid~ The diglycigyl etller of bispllenol A is usually prepared b~ reacting bisphenol A, viz~, 2,2-bis-(4-hydroxyphenol)-,... .
~- ~ propane, ~ith ep:Lhalohydrin, usually epichlorohydrin, using an excess of epihalohydrin in the process. The reaction mixture therefore comprises a mixture ~i i , ~'' ' ,, . .: .
i~": -- 10 --':,;", ~ .
,~ ,~,..
' '",'.' ' !.' i.

:
Lo9oo4(~

~` of the diglycidyl ether of bisphenol A and epihalohydrin. The diglycidyl ether of bisphenol ~ is usually puri~ied by removing the epihalohydrin. Since the :.~
preferred embodiment of the present invention employs a mixture of the two ~: - components, removal of the epihalohydrin ~rom the reaction mixture can be r.~ eliminated or at least reduced, when diglycidyl ether of bisphenol A is prepared ~` ~ for use in the instant process~ This results in a savings of time, equipment and capital.
; In all o$ the embodiments, the diglycidyl ether of bisphenol A is - added to ethylenically unsaturated monocarboxylic acid while the weight of reactive solvent in the reaction mixture is at least about 5 percent of the ~ su~ of the wei~hts of the resin and reactive solvent present in the reaction - mixture. The rate of addition is widely variable and depends upon such factors ` as reactor size, charge size, reaction temperature, available heating area, heating efficiency and mixing efficiency. The addition rate, however, should .,:
~ot be so great as to gel the contents of the reactor. It is preferred that -;; the addition be gradual. The reaction may be carried out continuously, semi-continuously or batchwise. It is most often conducted batchwise.
;: . .
The temperature at which the reaction is conducted may vary widely.
Ordinarily, the temperature is in the range of from about 50C. to about 130C.
ore often, the temperature is in the range of from about 80C. to about 120C.
i,- :' A temperature in the range of from about 100C. to about 115C. is preferred.

The reaction is usually conducted at atmospheric pressure, although ` greater or lesser pressures may be enlployed, if desired.

-~ The epihalohydrin employed i~ usually epichlorohydrin, epibromohydrin `' or mixtures o epichlorohydri~ and epib~omohydFin. The use S epichlorohydrin .-, ":
~ ~ is preerred.
:,.-: ,....
i~ ~ The-values of a, b and c. in the product may VarY-, depending upon .:
whether acrylic acid, ~ethacr~lic acid or mi~tures o acrylic acid and meth-, ... .
,- acrylic acid are used in the process~

~ ,, .
;.".:
r - 1 1 ~

''' `''--'`' '~
.,, ., - , . .

004(~
`~,~ .;
~ The radiation curable coating composition may consist of substantially '' t ~"',;
` only the resin dissolved in the react~Ve solvent, bu~ other ~aterials are ~- often also present.
,., , ,:
,~ ~ l~en the coating composition is to be cured by exposure to !~ ultraviolet light photoinitiator, photosensitizer or a mixture of photoinitiator ''`t', and photosensitizer is usuall~ present~
~,.....
: Photoinitiators are compounds which absorb photons and thereby obtain energy to form radical pairs, at least one of which is available to initiate ~r.~' ' addition polymerization of acrylic or methacrylic groups in the ~ell-known - manner. Photosensitizers are compounds which are good absorbers of photons, but which are themselves poor photoinitiators. They absorb photons to produce excited molecules which then interact with a second compound to produce free ~ ,. . .
. radicals suitable for initiation of addition polymerization. The second compound may be a monomer, a polymer or an added initiator. Examples of photoinitiators are benzoin, methyl benzoin ether, butyl benzoin ether, isobutyl benzoin ether, -diethoxyacetophenone and ~-chloroacetophenone.~ Examples of photosensitizers are benzil, l-naphthaldehyde, anthraquinone~ benzophenone, 3-methoxybenzophenone, benzaldehyde and anthrone.
The amount of photoinitiator, photosensitizer or mixture of photo-~",, initiator and photosensitizer present in the radiation curable coating composition can vary widely. When any of these materials are present, the amount is usually in the range of from about 0.01 to about 10 percent by weight of the binder of :i the coating composition. ~ost o~ten the amount is in the range o~ from about ~ ~ 0,1 to about 5 percent by we~ght o~ the binder. When the coating is to be cured m by exposure to ionizing radiation~ these ~aterials are usually o~itted from the r "~
coating composition, a~though their presence is pernlissible~
Extender pigments are often present in the radiation curable coating composition, particularl~J ~hen the coating composition is used as A , ~ a filler for wood or composition board such as particle board~ hardboard of l ., ., .. . . .
, ~, .
. ', 1(~9~
., the Masonite type, flake board and chip board. The extender pigment gives the coating composition a paste-like consistency and, upon curing, provides an easily sandable surface. When ultraviolet light is ~Ised to cure the film, it is preferred that the extender pigment be sllbsLantia]ly trans-parent to ultraviolet light. Examples of ultravio:Let :Light transparent extender pigments are silica, calcium carbonate, barium sulfate, talc, aluminum silicates, sodium aluminum silicates and potassium a]uminum silicates. When used, extender pigment is usually present in an amount in the range of from about 5 percent to about 85 percent by weight of the radiation curable coating composition. Ordinarily, the amount is in the range of from about 10 percent to about 75 percent by weight of the ., coating composition. An amount in the range of from about 30 percent to about 70 percent by weight is preferred. Mixtures of extender pigments as well as individual extender pigments may be employed.

... . .
- Hidlng and/or colormg pigment may optionally be present.
When the pigment is of the ultraviolet light absorbing type and the coating composition is to be cured by exposure to ultraviolet light, the pigment should be used in amounts which do not preclude curing of the ~ interior of the coating. The maximum amount is therefore related to the -~ thickness of the coating to be curéd. Thin coatings may tolerate more ` ultraviolet light absorbing pigment than thick coatings. Since ionizing ,;, .::
radiation is much more penetrating than ultraviolet ligllt, there is usually no significant problem with absorption of radiatioll by the pigment.
When used, hiding and/or coloring pigment is usua]ly present in an amount .... .
;~
in the range of from about 0.1 percent to about 60 percent by weight of the ~' coating composition. For thicker coatings, an amount in the range of from about ~:; O.S percent to about 50 percent is usually satisfactory. Examples of ultra-.
,j~ violet light absorbing hiding pigments are titanium ~io~ide, antimony oxide, . .
'.' , ~ 13 -,;:

, . . . , '~". , ' ~ ,:, ` .

0(~o 'f,. '` .' ~
;;'~ zirconium oxide, zinc sulfide and lithopone. Examples of coloring pigments ~ are iron oxides, caclmium sulfide, carbon black, phtlla]ocyanine blue, .;.....
phthalocyanine green, indanthrone blue, ultramarine blue, chromium oxide, burnt umber, ben7idine yellow, toluidine red and aluminum powder. Individual . pigments or mixtures of hiding and/or coloring pigments may be used.

- Mixtures of extender pigments, hiding pigments and/or coloring ; . . ~
pigments may also be employed.

~ Dyes in their customarily used amounts may be present in the ; ~ coating composition.
~- .
~ Although not ordinarily desired, minor amounts, usually in the ' J':' range of from about 0.1 to about 20 percent by weight of the vehicle, of ~ volatile reactive solvent and/or inert volatile organic solvent may be :'.' present in the radiation curable coating composition.
x, - Other relatively nonvolatile reactive solvents such as vinyl pyrrolidone may also be present. When used, they are generally present -; in an amount in the range of from about 0.1 percent to about 50 percent ~- by weight of the binder. An amount in the range of from about 5 percent to about 25 percent by weight of the binder is typical.
nother optional ingredient is thermoplastic resin. ~len present, these are usually present in an amount in the range of from about 0.1 percent ;Is. to about 50 percent by weigllt oF the binder of the radlation curable coating composition. Typically, the amount is in the range oE from about 1 percent - to about 25 percent by weight of the binder. Examples of thermoplastic resins which may be used are cellulose acetate, cellulose acetate butyrate, poly (vinyl chloride), copolymers of vinyl chloride and vinyl acetate, saturated ~- polyesters, homopolymers and interpolymers of methyl methacrylate, methyl acrylate, ethyl acrylate, ethyl methacrylate, butyl acry]ate, butyl meth-;r~
~ acrylate, 2-ethylhexyl acrylate, styrene and vinyl toluene. Individual ., ~. ....................................................................... .
thermoplastic resins or mixtures of such resins are useful. Brittle, friable thermoplastic resins are preferred in coating compositions used for filling wood. Examples are rosin, resins derived from rosin, chlorinated paraffins, chlorinated rubber, petroleum hydrocarbon resins and hard gums.
,: ~
., ;. .
; - 14 -:t ..
':. 1 ' ; ~'-"., "','' , . .
~',' ~ ' .

;
~; :10~004(~
Various additional materials may be added to adjust the viscosity ' .
~ ~ of the coating composition. ~xamples of such materials are fumed silica, ;`. . ~IJ
castor oil based compositions (e.g., Thixatrol ST, ~aker Castor Oil Company), modified clays, 12-hydroxystearic acid, tetrabutyl orthotitanate and micro-'; crystalline cellulose. When used, these materlals are usually present in an amount in the range of from about 0.5 percent to about 15 percent by weight of the binder.
The radiation curable coating compositions of the invention are . usually prepared by simply admixing the solution of resin dissolved in reactive solvent with such other ingredients as may be present. Although ; mixing is usually accomplished at room temperature, elevated temperatures - are sometimes used. The maximum temperature which is usable depends upon the heat stability of the ingredients. Temperatures above about 120C. are .: -.; only rarely employed.

The radiation curable coating compositions are used to form cured .,.,.., ~
`f-- adherent coatings on substrates. The substrate is coated with the coating ` composition using substantially any technique known to the art. These ' include spraying, curtain coating, dipping, direct roll coating, reverse . , -~ rol] coating, painting, brushing, printing, drawing and extrusion. The ~, coated substrate is then exposed to radiation of sufficient intensity for ` a time sufficient to crosslink the coating. The times of exposure to ~,.~ . . .
~,; radiation and the intensity of the radiation to which the coating compo-sition is exposed may vary greatly. Generally, the exposure to radiation should continue until the C-stage is reached wllen hard, solvent resistant . .
films result. In certain applications, however, i~ may be desirable for the curing to continue only until the B-stage, viz., gel stage, has been - obtained.
:;:
,~
....
''~ .;'' ' :', ,, .
.... .

' ':.'`
. .~ .
: .;. . , ,~, . , ' . .:
::'.' . , , :
:: ; .

,"~ 0~
;~: Substrates which may be coated with tlle compo~qitions of this ~.
,~,, ,~
invention may vary widely in their properties. Organic substrates such ~- as wood, fiberboard, particle board, eomposition board, paper, cardboard and various polymers such as polyesters, polyamides, cured phenolic resins, : .
, ~ cured aminoplasts, acrylics, polyurethanes and rubber may be used. Inorganic -:
substrates are e~emplified by glass, quartz and ceramic materials. ~lany -: metallic substrates may be coated. Exemplary metallic substrates are iron, : ..:....
steel, stainless steel, copper, brass, bron~e, alumLIlum, magnesium, titanium, ; nickel, chronium, zinc and alloys.

Cured coatings of the radiation curable coating composition . usually have thicknesses in the range of from about O.OOl millimeter to ;i., - . .
~;;` about 3 millimeters. More often they have thicknesses in the range of from ~.',`.'''~
about 0.007 millimeter to about 0.3 millimeter. When the radiation curable coating composition is a radiation curable printing ink, the cured coatings usually have thicknesses in the range of from about O.OOl millimeter to about F~
:; 0.03 millimeter.
The coatings of this invention may be cured by exposure to ioni~ing radiation. Ioni~ing radiation is radiation possessing an energy at least sufEicient to produce ions either directly or indirectly in a medium composed of common elements such as air or water and includes ionizing particle radiation'and ioni~ing electromagnetie radiation. Ioni~ing particle radiation designates the emission of eleetrons or accelerated nuclear particles such as -; protons, alpha particles, deuterons, beta particles, neutrons or their analogs.
,,.".~:, .~ .
~ ~ Charged particles can be accelerated using such clevices as resonance cllamber '~:
accelerators, DC potential gradient accelerators, betatrons, synchrotrons, cyclotrons, etc- Neutron racliation can be produced by bombar(ling a selected .,.. ~,:i. :. .
,~ light metal such as beryllium with positive particles of higll energy. Ionizing : ::
., .
~ particle radiation can also be obtained by the use of an atomic pile, ;
., .. ~j..... ..
,~ ~ 16 -.,: .
i-;'.'~'..:
~ . .
'`'-"::
. :....
.
:',j:. ..

Of~
;- ~ radioactive isotopes or other natural or synthetic radloactive materials.
Ionizing electromagnetic radiation comprises high energy photons. Examples ~` ~ are X-rays, bremsstrahlung and gamma rays.
"
~ X-rays may be produced when a metallic target such as tungsten, f . `
copper or molybdenum is bombarded with electrons of suitable energy. This ~ ~ energy is conferred to the electrons by accelerators, usually, but not !,,;,~ ', necessarily, of the linear type. Travelling wave linear accelerators, standing wave linear accelerators and DC potential gradient linear accelerators are f,``''''~" ordinarily employed for this purpose.
f `:
.- Bremsstrahlung, also known as continuous X-rays, is produced by the deceleration of electrons. The continuum extends from a short-wave limit .. ..
` dependent upon the maximum energy of the electrons indefinitely toward the f,;.-.'.`~" long wavelength end of the spectrum.
Gamma rays may be obtained by means of a nuclear reactor, such as a pile, by the use of natural or synthetic radioactive materials such as cobalt 60 or radium which emit gamma rays, or by absorption of a neutron in the (n,y) reaction.
The ionizing radiation, wllether particle radiation or electro-magnetic radiation, ordinarily has an energy of at least about lO electron ~` ~ volts. While there is no upper limit to the energy of ionizing radiation ,~ ~
~- which can,be used advantageously, the effects desired in the practice of ~, . .
~ this invention can be accomplished without resorting to the use of ionizing ;. .
radiation having energies above about 20,000,000 electron volts.

~ Accelerated electrons is the preferred ioni~ing radiation for ,~ crosslinking coatings of the radiation curable coating composition of the -: . .
' ~ invention. Bremsstrahlung generated by the deceleratlon of the electrons is also present a~d probably contributes to crosslinking. Varlous types of linear elect~on accelerators are known, for example, the ARCO type travelllng , '''`', :...,,.;
~ ';s::,, ... .
~ ~ / y ~ 17 ,i.::
~, .,,.;
: .
. ~ . , .
....
~:.: . . .
.

~09t)~0 wave accelerator, model Mark I, operating at 3 to ]0 million electron volts 1~ supplied by High Voltage Engineering Corporation, Burlington, ~ass., or ~, j . .
other types of accelerators such as are described ln United States Patent No. 2,763,609 and British Patent Specification No. 762,953 are sat:Lsfactory for the practice of this invention. Usually the electrons are accelerated to energies in the range of from about lO,OOO electron volts to about l,000,000 electron volts. Typically, the energy is in the range of Erom about 20,000 electron volts to about 500,000 electron volts. Preferably, the energy is in the range of from about 25,000 electron volts to about ,. .
~, 200,000 electron volts.

~ The unit of dose of ionizing radiation is the "rad" which is ,' ~ equal to lOO ergs of energy absorbed from ionizing radiation per gram of : ,"...
material being irradiated. Dose is initially determined using an absolute ~.~ method such as calorimetry or ionization dosimetry. These absolute methods .~ ",~ .
are quite sophisticated and hence are not generally practical for routine determinations. Once a radiatlon field has been explored by an absolute ~.;. .
method of dosimetry, it is possible to calibrate secondary radiation indicators in that field using relative dosimetry techniques. One simple : ` ..
~; method of relative dosimetry is based upon the bleaching of blue cellophane - by ionizing radiation.~ The blue cellophane is exposec1 to a standard source : :. .
., .; .
- ;~ for a known time and the transmittance is measured with a spectrophotometer :,.

....
-- at 655 nanometers. The transmittance of unexposed ce].lophane is also measured and the percent change in transmittance due to exposure to ioni~ing - :;..
....
racliation is calculated. From several such readings and calculations~ a graph may be constructed relating change in transmittance with dose. A
-;~ blue cellophane manufactured by the R.I. duront deNcmo1lrs & Company has been used for this purpose. The calibrated blue ce1]ol-l1ane mny thc!11 be ~:~ used to calibrate other sources of the same kind of radiation and other : :,.
~; .
.:.

:,:, . " ~
~ 18 ~
:i.
~.

;~, `
: -, `:

900~Lo , i~
~ kinds of blue cellophane which may be used in routine wnrk. Avisco .
~ cellophane 195 ~IS light blue manuEactured by the ~merican Viscose ; .
; Division of FMC Corporation has been calibrated ancl llsed Eor routine ` ` dose determinations. In practice, the calibrated blue cellophane is r,~.~.,,~,, exposed to the ionizing radiation before, after or simultaneously with the coated substrate being irradiated. The dose received by the coating ,~;:
is considered to be the same as that received by the bl-le cellopllane.
This presumes that the absorption of energy by the coating is the same ; as that of the blue cellophane. Except for materia]s containing rather ; large proportions of atoms oE very high atomic weight, the absorption : of ioniæing radiation is nearly independent of the identity of the material. The presumption is therefore valid for the ordinary work of - coatings manufacturing where very high degrees of accuracy of dose measure-~; .' ment are not needed. As used throughout the specification and claims, `^ dose is referenced to the bleaching of calibrated blue cellophane film ~, irrespective of the identity of the coating composition being irradiated.
Coatings of the radiation curable coating compositions of the . invention are ordinarily exposed to ionizing radiation in an amount in the ` ~- range of from about 0.01 megarad to about 20 megarads, although doses ' '.
greater than 20 megarads may be used satisfactorily. The dose, however, .;; .:
, . .
,; should not be so great that the chemical or physical properties of the . . "
coating are seriously lmpaired. Typically, the dose is in the range of from about 0.1 megarad to about 20 megarads. The preferred dose is in the rarlge ~ of from about 1 megarad to about 10 megarads.
`~;;` The coatings of the invention may also be cured by exposure to ;;

actinic light. ~ctinic light, as used herein, is electromagnetic radiation having a wavelength of 700 nanometers or less wllicll is capahle of produclng, .r" ~ ' ; either directly or indirectly, free radicals capable of initiating addition !. '.`
c~ polymerization of the coating compositions of the invention. Usually ~;` .
.. ..

` 1 9 --- :;
. '`;I
. ' :,; ~`~`~ ` .

r~, .~`;
photoinitiator, photosensitizer or mixtures of photol~itiator and photo-. . .
sensitizer are present to absorb photons and produce the free radicals,although in some cases, these materials are not neede(l. Actinic light possesses insufficient energy to produce ions in a medi~lm composed of ~- common elements such as air or water and hence, has an energy below about '.' !~` .:
10 electron volts. The most commonly used form of actinic light is ultra-violet light, vi~., electromagnetic radiation having a wavelength in the ~:.
range of from about 180 nanometers to about 460 nanometers, although actinic light of greater or shorter wavelength may also be used effectively.

Any suitable source whicll emits ultraviolet light may be used in tlle practice of this invention. Suitable sources are mercury arcs, carbon arcs, low pressure mercury lamps, medium pressure mercury lalllps, high pressure mercury lamps, swirl-flow plasma arc, ultraviolet light emitting diodes and ultraviolet light emitting lasers. Particularly preferred are ultraviolet light emitting lamps of the medium or high pressure mercury vapor type.
Such lamps usually have fused quart~ envelopes to witllstand the heat and transmit the ultraviolet radiation and are ordinarily in the form of long tubes having an electrode at either end. Examples of these lamps are PPG Models 60-2032~ 60-0393~ 60-0197 and 60-2031 and llanovia Models 6512A431 6542A431~ 6565A431 and 6577A431~ Similarly, any suitable source producing ,:;
~ actinic li~ht having greater or shorter wavelengths than ultraviolet light . . .: .
~ may be used. Many types of such sources are well known.
: :i -- The times of exposure to actinic light and the intensity of actinic ';'''~
light to which the coating composition is exposecl may vary greatly. In keeping with the general principles heretofore set forth, the exposure to actinic light ;~ shoulcl usually continue until the C-stage is obtained. Ilowever, for certain ~ applications, the exposure may be stopped when the B-stage has been achieved.
: ,~
;1~ In the illustrative examples which follow, all parts are parts by ~ weight and all percentages are percentages by weight unless otherwise specified.
.... .
;,''`
, !
~ 20 ~

~., : ....................................... .
':;
. .:-.
:,:
' ''~ ' .

lQ90(34(~
1~AMPLE I
:
- A reactor equipped with a thermometer, a he.lter, an agitator and a reflux condenser ls charged with 137 parts epibromollyclrin and 0.3 .
part hydroquinone. The charge is heated to 100C. ancl tllen 72 parts :, acrylic acid is added dropwise over a period of one hour. After the ::
addition is completed, the reaction mixture is held at teTmperatures in the range of from 100C. to 115C. for seven llours and then cooled to room temperature. The product is placed in a distillatlon apparatus ,~ :..
;~ ~ and distilled at an absolute pressure in the range o~ from about 200 to - about 533 dynes per square centimeter while the vapor temperature at the :~ ,.,:
~ - head of the distillation column is in the range of from 43.5C. to 59C.

;~ The product is a mixture of 3-bromo-2-hydroxypropyl acrylate . .
` and 2-bromo-1-(hydroxymethyl)ethyl acrylate.

;~ EXAMPLE Il ,.~ . ., :
reactor equipped with a thermometer, a heater, an agitator and a condenser is charged with 1730 parts acrylic acid, 12 parts of 50 percent ? ,.. ., p; aqueous trimethyl benzyl ammonium hydroxide solution and 8 parts 2,6-di-tert-^^~ butyl-4-methylphenol and heated to 95C. The dropwise addition of 2320 parts ; epichlorohydrin of about 96 percent purity is begun. Twelve hours later ,,,:. .
.'"! `."'. (temperature: 100C.), the addition has been completed. The reaction mixture ~'? iS allowed to cool overnight. The next morning, the reaction mixture is heated to 90C. and held at a temperature in the range of from about 90C. to about 105C. for 6~1/2 hours and then cooled to room temperature. The product i9 :.
found to have an epoxy number of infinity, an acid number oE 4.17, a hydroxyl number of 275, a Gardner color of less than one and to contain 0.015 percent ~; water ;md 20.75 percent chlorine.
S ' The product is a mixture of 3-chloro-2-hydroxyr)ropyl acrylate and 2-chloro-l-(hydroxymethyl)ethyl acrylate.
:,' ,:
; - .:, ',' ,; .
',, .: '.'-. :. . : , , : , l r!~;; 9 0 (~4 0 ~", ~
~ E _ PLE III
~, ;, : A reactor equipped with a thermometer, a heater, an agitator and a condenser is charged with 1584 parts acrylic acid, ll parts triphenyl-~`~ phosphine and 7.48 parts 2,6-di-tert-butyl-4-methylphenol and heated to 102C.
Over a period of four hours and eight minutes, 2145 ~arts epichlorohydrin is added while maintaining the temperature in the range oE from about 100C. to about 107.5C. At the end of this period, the temperature oE the reaction .~ ~
~ mixture is 104.5C. The reaction mixture is then heated. Aftcr fifteen -,. ~
- minutes, tlle temperature has risen to 114C. Ten minutes later, the temperature is 116C. and power to the heater lS shut off. Thirteen minutes later, the temperature is 112C. and a portion of the power is restored to the .; heater. Fifty-seven minutes later, the temperature is 106C. The ~- ` temperature is then maintained in the range of from about 106C. to about .~ 107C. for fifty-five minutes Power to the heater is shut off and the r~ reaction mixture is cooled. The reaction mixture is then filtered through ~- diatomaceous earth filter aid. The product, which is the filtrate, is . .
~, Eound to have an epoxy number of infinity, an acid number of 0.73, a :, -hydroxyl number of 275, a Gardner color of l and to contain 20.2 percent chlorine. The product is a mixture of 3-chloro-2-hydroxypropyl acrylate and 2-chlo~o-1-(hydroxymethyl)ethyl acrylate containing 3.06 percent free ,'~` epichlorohydrin.

~1 .
i, .ii .
t '~ .
" ', ~ ~ .
~ ' . . ~ . ' .
. ' ' , '"' '' ~;' .'',.',`' ''~. '..
' '".
'''.';.' .

,, :... . .
:',.
. ~

~` ~[)90V4() ...
EXAMpLE IV

A reactive solvent is prepared by admixing IO0 parts 3-chloro-2-hydroxypropyl acrylate, 50 parts 3-cllloro-2-hy(lroxypropy] methacrylate, . , 25 parts 3-bromo-2-hydroxypropyl acrylate, 15 parts 2-chloro-1-(hydroxymethyl)-ethyl acrylate and 10 parts 2-bromo-1-(hydroxymethyl)etlly] methacrylate.
The reactive solvent is represented by the formula:
,...- :.,:
~: , ~ 'C~l2~0 284 'f 2 )0.119 , I ~
Cll2=C~O CH f cl~ 2 0.856 0.144 . . O \ 011 /
/ 0.881 .
i` XAMPLE V
: :~
; A reactor equipped with a thermometer, a heater, a cooler, an agitator, a condenser set for total reflux, a source of air and `;; a source of nitrogen is charged with 1156 parts acrylic acid, 0.44i~ part methyl hydroquinone, 6.1 parts 2,6-di-tert-butyl-4-methylphenol, 21.1 parts 2-[2-[4-(1,1,3,3-tetramethylbutyl)-3-methy]phenoxy~ethoxy]
-` ethyl dimethyl ben~yl ammonium chloride monohydrate and 205 parts toluene ~?~.-. and a slight air sparge is applied. The charge is then heated to 107C.
B Over a pe~iod of 3-1/2 hours 2915 parts bisphenol A-diglycidyl ether - (Epon 828; Shell Chemical Co.) which has been preheated to a temperature .
~` in the range of from 51.6C. to 54.6C. is added to the reactor while j- maintaining the temperature of the reaction mlxture in the range of from 107C. to 109C. Upon completion of the addition, the temperature of the ~-` reaction mixture is held in the range of from 107C. to 110C. for 3-3/4 hours. At the end of this period, the condenser is set ior total dis-'"'~"' - , :.
~':`'.
. .
.,:- .
''"';:
' . .

~ ~ 9 ~ - 23 -., .
.,;, .. . ' , ~ `:
~ 10~04~
, -! tillation, viz., no condensate is returned to the reactor, and both air ,.,:
and nitrogen sparges are applied. The reaction m:Lxture is held at a temperature in the range of from 108C. to 113~C. for 5 hours and distillate is removed. At the conclusion of t:his period, heat is sllut oEf, cooling is applied and a slight air sparge is maintained. One hour later when the ." ~
~ - temperature has reached 90.6C., the product is discharged from the reactor j ~- through a nylon bag filter into containers. The product, which is the ~ diacrylate of bisphenol A-diglycidyl ether, is found lo have an acid number ;:',. .:..
~` of 0.5, a hydroxyl number of 214 and to contain 0.0l percent water and 0.2 '.~. . ~ .: -~ percent toluene. A 75 percent solution of the product in ethyl cellosolve ~..,:
~ has a Gardner-lloldt viscosity of T-U. The product may be depicted as having . ~
, `~ the structural formula:
~.
,.
r~.:

C112=Cl gOC112CiiCH20~ Cil3 ~ OC112CiiC1120gCil= Cli2 n ., .
~ where the value of n is in the range of from O to about l.
~.; .:.
.:
, , ,' .i .
~;: ,. .
:.: :.
: ..
,:
: .
., -;
.;,, :
, :, ' .,, .'!
' ,:';
:' ~: ', ' ~,`:
. ` .:
.' .
,'., ~,:
: ' ` " ' , ~,;
~ - 24 -, ............................................................... .
,.. , .. __. ~__.. ,_ ,. ..
'.:

~:`
?. ~ ` 1()9 V04 ~) EXAMPLE yI

~ A reactor equipped with a thermometer, a heater, a cooler, an :i ~'. .
~-;; agitator, a conclenser set for total reflux, a source of a-ir and a source ; ,:, ~
of nitrogen is charged with 380.8 parts acrylic acid, :L.87 parts i ~ 2,6-di-tert-butyl-4-methylphenol and 1.86 parts triphenylpllosphine and i:-::.--an air sparge is applied. The charge is then heated to l]0C. A mixture .. comprising 385 parts epichlorohydrin and 166.6 parts Epon 828 blsphenol A--"., diglycidyl ether is preheated to about 110C. Over a period of 4 hours, ~- ~ 551.6 parts of the preheated mixture is added to the reactor while main-~',`'. , taining the temperature of the reaction mixture in the range of from 110C.
,;-; ;, : :, ` to 111.7C. Upon completion of the addition, the temperature of the ru`~ reaction mixture is held in the range of from 110C. to 1]3C. for 75 ~- minutes. At the end of this period (temperature: 112.2C.), heat is shut off and cooling is applied. Fifteen minutes later (temperature:
96.1C.), the condenser is set for distillation, a slight vacuum of 1.2 x 10 dynes per square centimeter is applied while maintaining an ;::
i` air sparge and distillation is begun. Two hours later (temperature:

;~ 97.8C.), 21 parts distillate has been removed and the vacuum is removed.
p, "
Thirty minutes later (temperature: 97.2C.), a slight vacuum of 1.07 x 10 dynes per square centimeter is applied while ~aintaining an ;~5 air sparge and distillation is again begun. Two hours later (temperature:

.,.~ .;
~; 97.2C.), 7 additional parts distillate has been removed and the vacuum i; and air sparge are removed. Fifteen minutes later (temperature: 97.8C.), ~ the vacuum and air sparge are reapplied. Thirty minutes later (temperature:
,.~ ~..
::?; ' 97.8C.), the vacuum and air sparge are removed, heat is shut off and cooling is applied. Forty-five minutes later when tl~e tremrcrature has reached 54.4C., the product is dischargecl througll a filter into containers.
The product, which is a mixture of 3-chloro-2-hydroxypropyl acrylate, 2-chloro-l-.;~,............... ~
(hydroxymethyl)ethyl acrylate and the diacrylate of Epon 828 bisphenol A-- ::

. , - 25 -~:, j;.~ ,.
:.' ' ~ :
.
:, 9~o~o diglycidyl ether, is found to have an acid number of 3.9, a Garclner-lloldt ~;. viscosity of K, a hydroxyl number of 242 ancl to contaLIl 0.02 percent water ~` and 14.1 percent chlorine.
. ..:"
,,.
~ 'LE yII
~ .. ~ .~
i ? B A filler composition is prepared by admixing 75 parts of the di-acrylate of Epon 828 bisphenol ~-diglycidyl ether, 108 p<lrts of the product of Example II, 100 parts Montana platy talc having a mean particle size of less than 2 micrometers ~Mistron Vapor; United Sierra Division of Cypress Mines Corp.) and 3.7 parts isobutyl benzoin ether. The viscosity of the ,. ., ; .
~ filler composition is determined to be 296,000 centipoises by a Brookfield . --. .
~ viscometer using a number 7 spindle at 10 revolutions per minute.
,~ The filler composition is drawn clown on alumin-lm substrates using a number 018 wire wound drawbar. The coated substrates are passed once, ,.,;
. in air, through an uItraviolet light processor containing Eour medium . , - pressure mercury vapor lamps which are emitting ultraviolet light. The ;----:
lamps are 8.89 centimeters above the plane of the substrate surface.
-~ Following exposure to the ultraviolet light, the coated substrates are evaluated for degree of cure by rubbing the coating with an acetone soaked cloth under approximately similar conditions of pressure and frequency and noting the number of rubs (wherein one rub is a combined back and forth j ~;;` motion) necessary to expose the substrate. ~ maximum oE one hundred rubs , .~ .~ .
is used. The speed with which the coated substrates nre passed under the , . ~
ultraviolet light emitting lamps and the results of the acetone rub test ~- are shown in Table ~.
.~ ....... .
.",.~,:
~,~,...... ..
~, ",~
.

..:,.

;i .
. . ,.~. , . . i ~
:-~v - 26 -',., ':~
... ..
~;,...
,: 1' . ,.~;
:::
..
'~'','' ' '~ .

': ~

:.
. - .
~ Tabl~_1 i: , Speed of Travel Through Numl~er Or ~cetone Rubs ~' ~ Ultraviolet Light Processor to ~xpose Snbstrate -` feet/minutemeters/minute . _ 12~2 ~lO0 r ~ ~ 5 0 .15 ~ 2 ;~ ] 00 ]8~3 ~lO0 2l~ 43 ~.I0)00 . ~ 9 0 2 7 ~ 4 / l 0 0 . ~ 100 30~ 5 ~ ] 00 . 150 45 ~ 7 7100 54 9 ~lQ0 200 61 ~ 0 80 ~,!. ~ ',;
'-' Using the same drawbar, the filler composition is drawn down on - an unsanded particle board substrate. The coated substrate is pas~sed once, '; ~ in alr, through the ultraviolet light processor at 150 feet/minute t45~ 7 meters/minute~ to produce a filled particle board. The substrate is not : exposed after 100 acetone rubs. Adhesion of the cured coating to the particle ~ board is tested by the crosshatch test. In this test, a Eirst serles of parallel ; .:
. : lines and a second series of'parallel lines which are perpendicular to the lines ~-- of the first series are scribed through the coating to the substrate so as to :; .
~ ~ ' form a checkerboard pattern of squares,'each square being about 3~175 :'~ millimeters on a side. Three times No. 60Q Scotch brand adhesive tape ;.i............... (3M Corp.) is applied to the scribed area and pulled off suddenly. The ','~ percent of the taped crosshatched area from which coating has been removed ,:, .; .:
''`'' is then determined. ~ loss in the ran8e of 0 percent to S percent is given - :,.:
a rating of good. A loss in the range of from above 5 percent to 30 percent is given a rating of fair. A loss above 30 percent -Ls given a rating of . . . .
;';~. poor. Wllen subjected to the crosshatch test, the cured coating on the '~ particle boarcl substrate llas a crossllatcll rating Or goocl.
: . .
:
.`'., ~ r ~ ~ ~ O r ,: .
, - 27 -, . . .
, . ..
.~'.::
;~ ~ . .
.: .,.:
.., ~.:

r ' . 109004LO

~ Sanding characteristi.cs of the cured coatln~ 011 the I~arti.cle ." ~ .
.. board are tested by the sancling test. In this test, tlle coating is sanded with number 35n grit sandpaper using 10 back and forth rubs. The sandpaper is then flicked or brushed against a cloth. The percent Or the powder retained ~. ;:;-ln the sandpaper is then determined. A low degree of re~entlon in the sand- -. paper i~s desirable. ~len subjected to the sancling tesL, the cured coatl.ng on , ~;
~.. the particle board had a sanding rating of ~ 5 percent retention.
. .
i A groundcoat composition comprising an acryl:ic solvent base lacquer pigmented with titanium dioxide is drawn down on the unsanded filled particle board using a number 036 wire wound drawbar. The coated article is placed in an oven at 121C. for three minutes to produce a groundcoated panel. I~hen subjected to the crosshatch test, the groundcoated panel has a rat;.ng of -good. A portlon oE the groundcoated panel is lightly sanded. A topcoat ~ composition comprising a diethylene propylene maleate, styrene, the di-;.','': ~ ~
acrylate of I:pon 828 bisphenol A-diglycidyl ether, photoi.nitiator and fl.atting silica is drawn down over both the sanded and unsanded areas Usillg a number ~- 018 wire wound drawbar. The coated panel is passed once, in air, through the four lamp ultravio].et light processor described above at a speed of 20 feet/minute , r ~'.' (G.l meters/minute) to produce a topcoated pancl. I~len subjected to the . ...
~ crosshatch test, the topcoated sanded area has a rating of good and the top-~ ,,:. .:
. . coated unsa~ded area has a rating of fair.
,. . , - ., .,,., ,:
~;';' .
;;~.';

~ :.
' ,. ~" .
¢;~ `~ ' .
.......
,, .;:
. . .
: . .;

.:
: ~, "

',' "
. .. , .. __ .. _ .
:' ' ,: , , .

10 9 ~ 0 4 V
.
EX~MPLE VIII
r,~
A filler composition is prepared by admixing 36 parts of the di-~-;~- acxylate of Epon 828 bisphenol ~-diglycidyl ether, 8h parts of the product of Example III, 45 parts aluminum silicate having a mean particle - ~- size of 4.5 micrometers and a nodular particle shape (Minex #7, Indu~s1nin ? ~
: Etd., Ontario, Canada), 45 parts Mistron Vapor Mon~nna plsty talc and 2.1 ' parts isobutyl benzoin ether. The viscosity of the filler composition is ~` determined to be 40,000 centipoises by a Brookfield viscometer usinp, a number 7 spindle at 20 revolutions per minute and 20,000 centipoises uslng ` ~ a number 7 spindle at l00 revolutions per minute.

The filler composition is drawn down on particle board substrates ~,~
. using a number 018 wire wound drawbar. The coated substrates are passed once in air, through the four lamp ultraviolet light processor of Example VII to . ~ produce filled particle board. ~ollowing exposure to ultraviolet light, the filled particle board is evaluated for adhesion by the crosshatch test ~: described in Example VII , for sanding characteristics by the sanding t2st described in Example VII and for hardness by the pencil hardness test. The -~ pencil hardness test involves a set of pencils ranginp Erom 6B soft to 611 - hard. Starting with the hard end of tlle set, they are pus11ed in turn into , .~....... .
~ ,; the film. The first pencll which crumbles instead of penetrnting indLcates ., ~- the pencil hardness. The speed with which the coated substrates are passed .... .
under the ultraviolet light emitting lamps and the res1Jlts oE tlle tests are shown in Table 2.
". . .
.,~
,,~
:...
, :~;, . ., -, ,~.

~, . .

S~

: `
~:P9~04Q
- `
Table 2 ,. ., _ Speed o~ Travel Percent Powder I'hrougll Ultraviolet Retained on Crossllat(ll Adllesion, Penci]
Li~ht Processor Sandpaper y___ent removed llardness feet/minute meters/minute ,:
100 30.5 0 ~ 2 150 45.7 0 to 5 0 2 :- .
Uslng a number 018 wire wound drawbar, tl-e groundco~t composition :: .
~ described in Example Yll is drawn down on sanded an-l unsande(l portions of the ,:
~ filled particle board and placed in an oven at 121C. for 2-1/2 minutes to ,. . ..
~ produce a groundcoated panel. The groundcoated pane] is then subjected to - ~ the crossllatch test in both the areas where the filler was sanded and left unsanded. The data are shown in Table 3.
..`~ .`,' .r,~',' Table 3 '':`' ''':' `:
Speed of Travel Througll Crosshatcll ~dllesion, Ultraviolet Li~llt Processor percent removed : :, ~-~` feet/minute meters/minute Filler Sanded Piller Unsanded ,,::. i 100 30.5 0 0 150 45.7 5 .: . . . . . .. .. _ .,;, .
.~,., :: ..:
." ....
.
, ;:
::
,::

";:::

.... . .

~".

;' , :, ... .
,:
'.`:,'' !~

:, `
" ~ 30 -. . ........................ . .
. , .

)9~ 4~
F`: . ` -'- EX~MPLE IX

An intermediate compositLon is prepared by a(lmixing 775 parts of ~ the product of Example VI, 159 parts of the triacrylatP of pentaerithritol, ,, 12 ,,,,~ D ~
~;` ~ 46 parts epoxidi~ed linseed oil (Paraplex G-62; Rohm & llaas Co.) and 20 .,, ~
~ parts resinous silicone Elow addit:Lve (nyk-300; Byk-Mallinkrodt Co.).
. . -- .
..':, ~
A first base white composition i,s prepared by grinding 500 parts titanium dioxide pigment in 350 parts of the above intermediate composition ;'. ~
~ to a Hegman 7 grind and then thinning with 150 parts of the above intermediate ,'~ :,' ,, composition.
-.-, -, ~";~-, A first wllite coating composition is prepared by admixing 80 parts of r ", ~ the~above first base white composition, 8 parts methyl ethyl ketone9 0.8 part :-'~; ' methylanthraquinone and 0.8 part isobutyl ben~oin eeher. The viscosity of .:. ,~:
,:.',,~`' the first white coating composition is determined to be 1280 centipoises by a : ,:: ~ .
,;'' Brookfield viscomete'r using a number 5 spindle at 50 revolutions per minute ~, , and 840 centipoises using a number 5 spindle at 100 revolutions per minute.
, i ~
, ;:.
~ ' The first white coating composition is drawn down on aluminum , .
'', substrates using a number 006 wire wound drawbar. Separate coated ~ substrates are passed through the four lamp ultraviolet light processor r'.`,.~ of Exampqe VII at speeds of 15.2, 30.5, 45.7 and 6].0 meters per minute, , .. .
,~ respectively. Another coated substrate is passecl at a speed of 61.0 .~' meters per minute through the ultraviolet ligllt processor which has only three lamps in operation. The coatings of all coated sul)strates passed .'.` ',1 .
~ through the ultraviolet light processor having four lamps operating were :, ~, , dry and resistant to finger rubbing, but were ab]e to be removed by tape without previous crosshatching. Tape-off with previous crosshatching is eliminated for these coated substrates by post balcing Eor 2 minutes at 204.4C. in a circulating'air oven.

.~."'~ . ,.

i ," .~," -- 3 1 --~`, ~,.,.,, . "

:.
90a34!D

- A secontl wilite coating composition is preparcd by a(imixing 50 - parts oE the above first base white composition, 5.~ parts methyl ethyl ketone, 0.7 part methylanthraquinone, 0.7 part isol-utyl benzoin ether and 8 parts of the above intermediate composition. 'rhe visco~sity of the .second white coating composition is determined to be 640 centipoises by a Brookfield , - viscometer using a number 5 spindle at 100 revolllt-ions per minute.
.: ~
~;; The second white coating composition is drawn down on aluminum .:-~ substrates using a number 006 wirc wound drawbar. Separate coated substrates ... .
i are passed through the ultraviolet light processor in the same manner as ~^;,, that described above for the first white coating composition to obtain substantially the same results. Better hiding is provided by the first ~;..., ~
.r; wllite coating composition than tlle second white coating composition.

;` A second base white composition is prepared by grinding 415 parts ~- titanium dioxide pigment in 400 yarts of the above intermediace composition ~ to a }legman 7 grind and then thinning with 155 partæ of the above inter-$~
;; mediate composition.
. . .~ , .
, ;. ___ `
~ A third white coating composition is prepared by admixing - ,:...
50 parts of the above second base white composition, 5 parts methyl ....
; ethyl ketone, 0.6 part methylanthraquinone and 0.6 part isobutyl benzoin ;~ ether. The viscosity of the third white coating composLtion is determined .

, .
to be 200 centipoises by a Brookfield viscometer us:ing a number 5 spindle at 100 revolutions per minute and 220 centipoises u.sing a ntlml)er 4 æpindle at 100 revolutions per minute.
The third white coating composition is drawn down on aluminum ~j~ substrates using a number 006 wire wound drawbar. ~eparate coated sub-strates are passed through the ultraviolet ligllt processor in the same . ,.,.,; .
manner as that clescribed above for the first wllite coating composition to obtain substantially tlle same degree o~ lliding as obtained by the . .
~ ~irst white coating composition. The cured coating i9 tested for adhesion.

, ~ j ~ .; .

. ~

., , ..................................................................... . .

:: ., '~ . ` .: ' o9~o~

r ',' A fourth white coating composition is preparecl by aclmixing 70 . ~ parts of the above second base white composition, 7 parts methyl ethyl.. ketone, 1.6 parts methyl phenylglyoxylate, 0.8 part isobutyl benzoin .; ether and 0.21 part methylantllraquinone. The viSC05i.ty of the fourtl . .
; white coating composition is determined to be 180 centipoises by a Brookfield viscometer using a number 4 spindle at 100 revolutions per ... -.~ minute.
~:. The fourth white coating composition is drawn down on an '.~ aluminum substrate and passed once, in air, througll the four lamp ultra-". . ~ . .
violet light processor of Example VII at a speed of 61.0 meters per ;. minute to produce a hard, infusible coating showing good hicling. The ~ cured coating is tested for adhesion.
,' .,~ . .
.;.~ Of the four white coating compositions, the ~ourth white coating .'.'''~i' _',., composition provides the best aclhesion ancl the thil d wllite coating COlllpO-., .
~ sition provides the next best adhesion.
. ,. ~ ...
~XAMPLE X

B A solution is prepared by dissolvin~ 573 parts adhesion promoting resin (22D-54; Rohm ~ Haas Co.) in 397 parts hot metllyl ethyl ketone.
A first intermediate composition is preparecl by admixing 970 parts of the above solution, 1795 parts of the product of Fxample VI , 1108 parts of the triacrylate of pentaerithritol and 27 parts Paraplex G-62 epoxidi7ed linseed oil.
A second intermediate is prepared by grinding 1530 parts of the '~ . above first intermediate, 2370 parts titanium dioxide, 29 parts methyl-,j,~,; ~ .
anthraquinone, 38 parts spermaceti wax and 95 parts ~ylc-300 resinous silicone ,l Llow additive with a Cowles blade to a llegman 7 grincl.
. ...
,." .

r~ O ~
~ - 33 -, . ..
.,:.
~, :
,~
. ~ . . . . . . ...
:
! .. . . .
": '. . ' , . " ' : .

.
::`
,,,., lV90040 :
.':
A coating composition is prepared by adn1:ixil1g 4062 parts of the .
' above second intermediate, llO0 par~s of the above first intermediate, 283 .,:..;
parts 3-acrylyloxy-2,2-dimethylpropyl 3-acrylyloxy-2,2-dimethylpropionate, B 189 parts of a urea-formaldehyde resin c omposition (~1 Eor1nite F-240, Rohm &
i~ .,.
-` Haas Co.) having 60 percent solids (sol vents are xylol-butanol l:l.5), ~ 283 parts l-acrylyloxy-2-hydroxy-3-butox ypropane (prepi3red by reacting one :~ molar part acrylic acid with one molar p art l,2-epoxy-3-butoxypropane), 95 parts methyl phenylglyoxylate, 62 parts isobutyl benzoin ether and 283 parts methyl ethyl ketone.
The coating composition is dra wn down on an alumLnum substrate ....... .
- using a number 009 wire wound drawbar. The coated substrate is passed once, ':. .
~ in air, at a speed of 61.0 meter~s per minute througl1 the four lamp ultra-:. :..
~ violet light processor Gf Example VI~ to produce a hard, infusible coating.
-i When subjected to the crosshatch test of Example VII much of the coating is ,: :
~ ~ removed by the tape. After post baking for 2 minutes at 204.4C. in a cir-.~ culating air oven, a crosshatch rating of good is achieved. Submersion in buffered borax solution at 71.1C. for 30 minutes similarly yie]ds a cross-` hatch rating of good.
.. . . .

~,;,,.;
,.,,i, :.
, ,~.i~
,., 1 ~.

~ r ~

,:

.' ', '"' ' .~.~,, :; , .

.
.
. . .
,:

~ ~ , ~'' '' ' , .

.:

;' ' . ~ '. ` , ' , . ' .
- , . .: .

5`,~ O()~
.... .
~xample XI
; . .: .
r'~ A reactor equipped with a therm~meter, a heater, an agitator and . ;". ., . a condenser set for total reflux is charged with 1569 parts acrylic acid, .:; . .
`, 8 parts triphenyl phosphine and 12 parts 2,6-di-tert-b~ltyl-4-metllylphenol.
'; The charge is then heated to 102C. Over a perlod oE 4 llours, 873.6 parts .'.: ~
i Epon 828 bisphenol ~-diglycidyl ether and 1574 parts epichlorollydrLn are : ~
concurrently added as separate streams while maintaining the temperature .. ..
~; of the reaction mixture in the range of from 102C. to 110C. Upon completion ~-` of the addition, the reaction mixture is held in the range of from llO~C. to 118C. for 4-1/4 hours. At the end of this period (temperature: 117C.j, heat is shut off and the reaction mixture ls allowed to cool overnight to ...... .
,~ room temperature. The product is then heated to 60C. and Eiltered into a ,..,;:,.: ~ ~
container. The product, which is a mixture of 3-chloro-2-hydroxypropyl acrylate, - ~ 2-~hloro-1-(hydroxymethyl)ethyl acrylate and the dlacrylate of-Rpon 828 bisphenol . ..;.
~~diglycidyl ether is found to have an acid number of 3.73, a Gard~er-lloldt vis-cosity of L-M, a Gardner Color of lj a hydroxyl number of 273 and to contaln 0.021 ~, ~ percent water, 14.5 per~ent chlorine and less than 0.10 percent free epichlorohydrin.
~' .
;:
.`t''.
~{' ~i',,i '.`'.
'~? '~ .
~ _;
.;.
." ', .
~,'~,'.'' ~. S,~ "' i~"~`. ' ~,;
~,.. . .
;~r, ;~, ' ~ ' ;`~ . "'', ,Y~.,,.' ~ ' .r ~ ., J
,'' . _ ,'. ' ~ - 35 -:, :~. -, .
, ~.. , . .. ...... ___ ~_

Claims (16)

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

1. A radiation curable coating composition having a binder comprising resin represented by the formula:

dissolved in a reactive solvent represented by the formula:

wherein (a) the average value of n is in the range of from 0 to 3;
(b) the average values of a, b and c are each independently in the range of from 0 to 1;
(c) the average value of d is in the range of from 0 to l;
(d) the average value of e is in the range of from 0 to 1;
(e) d + e = l;
(f) the average value of f is in the range of from 0 to l;
(g) the average value of g is in the range of from 0 to l; and (h) f + g = 1.

2. The radiation curable coating composition of Claim 1 wherein said resin is present in an amount in the range of From about 5 percent to about 95 percent by weight of said binder and wherein said reactive solvent is present in an amount in the range of from about 5 percent to about 95 percent by weight of said binder.

3. The radiation curable coating composition of Claim 1 including photoinitiator, photosensitizer or a mixture of photoinitiator and photosensitizer in an amount in the range of from about 0.01 percent to about 10 percent by weight of said binder.

4. The radiation curable coating composition of Claim 1 including thermoplastic resin in an amount in the range of from about 0.1 percent to 50 percent by weight of said binder.

5. The radiation curable coating composition of Claim 1 including extender pigment in an amount in the range of from about 5 percent to about 85 percent by weight of said radiation curable coating composition.

6. The radiation curable coating composition of Claim 5 wherein said extender pigment is substantially transparent to ultraviolet light.

7. The radiation curable coating composition of Claim 1 including hiding pigment, coloring pigment or mixtures thereof in an amount in the range of from about 0.1 percent to about 60 percent by weight of said radiation curable coating composition.

8. The radiation curable coating composition of Claim 1 including ultraviolet light absorbing hiding pigment in the range of from about 0.1 to about 60 percent by weight of said radiation curable coating composition.

9. The radiation curable coating composition of Claim 8 wherein said ultraviolet light absorbing hiding pigment is titanium dioxide, antimony oxide, zirconium oxide, zinc sulfide, lithopone or mixtures thereof.

10. The radiation curable coating composition of Claim 1 wherein the average value of n is in the range of from 0 to 1.

11. The radiation curable coating composition of Claim 1, wherein the average values of a, b, c and e are zero and the average value of d is one.

12. A radiation curable coating composition comprising:
(a) a binder comprising resin represented by the formula dissolved in a reactive solvent which is 3-chloro-2-hydroxypropyl acrylate, 2-chloro-1-(hydroxymethyl)ethyl acrylate or a mixture thereof;
(b) photoinitiator, photosensitizer or a mixture of photoinitiator and photosensitizer, wherein (c) the average value of n is in the range of from 0 to 1;
(d) said resin is present in an amount in the range of from about 5 percent to about 95 percent by weight of said binder;
(e) said reactive solvent is present in an amount in the range of from about 5 percent to about 95 percent by weight of said binder;
(f) said photoinitiator, said photosensitizer or said mixture of photoinitiator and photosensitizer is present in an amount in the range of from about 0.01 percent to about 10 percent by weight of said binder.

13. The radiation curable coating composition of Claim 12, including extender pigment which is substantially transparent to ultraviolet light and which is present in an amount in the range of from about 30 percent to about 70 percent by weight of said radiation curable coating composition.

14. The radiation curable coating composition of Claim 12, including titanium dioxide in an amount in the range of from about 0.1 percent to about 60 percent by weight of said radiation curable coating composition.

15. An article comprising a substrate having thereon a cured coating of the radiation curable coating composition of Claim 1.

16. An article comprising a substrate having thereon a cured coating of the radiation curable coating composition of Claim 12.