Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~046178
This invention relates to matt paint compositions,
Matt paints have been produced for many years by
utilising relatively coarse inorganic extender particles
to disrupt the surface of a dry paint film and thus
produce a low surface gloss Although many useful
prod.ucts of this type have been us~d successfully~
it has come to be accepted that they have inherent
limitations in respect of properties such as bittiness,
stain removal and sheariness, It has also been observed
that when the surface of such a paint film is abraded
exposed fragments of brittle extender pigment particles
break away leaving disfiguring whitish streaks or
even glossy patches in the abraded areas.
One proposed method of overcoming these defects
is to replace the inorganic extender pigment particle~
with polymer beads of a similar diameter Such a
method is disclosed in, for example, Australian Patent
Specification ~o, 434658. Paints of this type are free
from most of the defects of conventional matt paints and
if the polymer beads used therein haye prime pigment~
for example titanium dioxide~ dispersed therein they ~
can e~;bit unusually high opacity. We have, however, :
observed that the colour range of paints of this type
is limited by the tendency, especially in those shades
having a low reflectance, for streakiness or slight
variations in colour to appear in the dry film, depending
on the method used to apply the paint to a substrate.
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We have now found that this problem can be overcome
by the use of polymer beads which fall within two
distinct size ranges, the first having diameters from
2-10~ and the second greater than 10 and not exceeding
40~, Furthermore, if the paint to be produced is to
have a reflectance of greater than 65% both types of
beads must be white and opaque. If the reflectance
is to be from 30 tQ 65% the smaller beads must be white
and opaque but the larger beads must be clear. At
reflectances below 30% both types of beads must be clear.
The volume proportion of beads having a diameter
greater than 10 and not exceeding 40~ must be from 45
to 55% of the total beads volume. ~he volume of beads
relative to the total non-volatile content of the
15 paint should be at least 55%~ but not more than 90% at ;
which point the mar resistance starts to deteriorate
appreciabl~.
A particularly useful attribute of some of these
compositions is that they have unusually high mar
resistance, for which purpose the larger beads should
be solid; that is they must be free of voids, and
preferably they should comprise polymer having a
maximum elongation at break of 40%.
~he matt paints to which we refer are conventional
to the ext0nt that the~ consist of liquid dispersions
of opacifying, colouring and/or film-modifying pigments
in paint vehicles. Dry films of the paint have a matt
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appearance. We use the expression "paint vehicles~
in its broad art-recognised sense of liquid film-
forming compositions whicb in turn may consist of
solutions or dispersions of film-forming polymer in
volatile liquids In accordance with e~tablished
practice we refer to the constituents of the liquid
paint composition which persist in a dry film thereof
as the non-volatile content of the paint.
~he composition of the paint vehicle i8 not incidental
to the performance of this invention. It must not
dissolve or chemically attack the Eolymer beads, ;-
butthis is self-evident since if it does so they will
no longer exist in the composition as beads. ~he ~ ~-
only limitation in the choice of paint vehiole is,
therefore, that it must be inert with respect to the
beads to be incorporated therein. ~he pai~ts may,
if desired~ comprise a proportion of inorganic extender
pigment but for the best results we prefer to avoid
the deliberate introduction into the paint of any
conventional inorganic extenders since in our experience
this predictibly detracts from its performan¢e.
By "reflectance" of a paint film we mean the
standard green reflectance measured with a tristimulus
differential colorimeter and denoted "G" in the American
Society for ~esting and Materials Method D2244-68.
~he green filter reflectance is used regardless of the
shade of the paint because of its close correlation
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with human vision. (Gardner-Sward "Paint Testing
Manual",13th edition,page 31).
The requirement to avoid colour variations is
of particular importance in formulating so-called tint
5 bases~ which ar~ ~s~entiall~ paints of standard tinting
strt~ngth to which controlled amounts of liquid tinter
are added to produce a range of standard paints shades.
In order to avoid the above-described undesirable
appearance and formulating compromises, we have found
it desirable in developing a so-called "universal
tinting system", to use three tint bases. In the
first of these, all beads are white and opaque; in the
second, beads in the smaller size range as defined
above are white and opaque but the larger beads are
not and in the third~ none of the beads is opaque.
~ he tint base from which any particular shade is
to be derived by the addition thereto of tinter is chosen -
as follows: For shades of reflectances above 65% a
tint base i~ which all beads are white and opaque is
chosen; for shades with reflectances between 30% and
65% a tint base in which the smaller beads only are
white and opaque is used and for shades with
reflectance~ below ~0% a tint base in which all beads
are clear should be used.
Bead diameters may be measured microscopicall~
but we have found it more convenient to use an
instrument such as Coulter Counter for this purpose.
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046~78
It is accepted that in any p~rticular batch of beads~
a minor proportion of them may lie outside of these
nominal size ranges, but such normal variation in
quality can be tolerated in performing this invention.
Suitable polymer beads may be prepared by, for
exam~le~ the polymerisation of an emulsion in water
of a syrup ¢omprising polymerisable elements convertible
to solid polymer, e.g. a solution in s-tyrene of an
unsaturated polyester. Other polymers which may be
prep~red in the form of beads by an emulsion technique
include urea-formaldehyde condensates and methacrylic
polymers.
White opaque beads may be prepared by similar ~-
methods, having first dispersed prime pigment, e.g.
titanium dioxide, in the syrup of convertible
elements before preparation of the emulsion in water,
In general, at least 1% by weight of white pigment is
requ-red to impart opacity to the beads. ~he opaque
nature of a bead is readily identified by examining
it microscopically using transmitted illumination.
Alternatively, opacity may be imparted to the
beads, at least in part, by forming in them a
vesiculated structure ~he vesicles may in turn comprise
a proportion of pigment particles trapped therein.
By a vesiculated particle ~e mean a particle comprising
a plurality of discrete air sacs or vesicles encased
in a shell of essentially non-porous polymer.
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` 1046178
Particles of this type are described in, for example,
- Australian patent specifi~ation No.439,432.
Certain materials which are utili9ed in the
example~ given hereinunder are identified as follows:
hydroxyethyl cellulose Natrosol 250 X.R or equivalent ,
poly(vinyl alcohol) '~elvatol 20/90 or equivalent
unsaturated polyester Crystic C/96 or equivaIent
resin
bactericide Proxel ~.~. or equivalent
styrene-maleic anhy- S.M.A~ 1440 ex Sinclair
dride copolymer Petrochemicals Inc.
Natrosol, Gelvatol, Crystic and Proxel are trade marks.
Clear Bead Slurry, 10-40 micron
~ he slurry was prepared as follows:
~ a solution of 0.33 parts of hydroxyethyl cellulose
in 49,11 parts of water 11.17 parts of a 7~/o solution
in water of an 80% hydrolysed polyvinyl alcohol was
added and stirred
A solution of 30.83 parts of an unsaturated
polyester resin and 1.12 parts of a 50% benzoyl
peroxide paste in 5.10 parts of styrene was added to
the above aqueous solution and mixed at high speed
until the largest emulsion particle visible under a
microscope was 40 micron diameter.
~he emulsion was stirred slowly and 0,18 parts of
diethyl aniline was added. ~he slow stirring was
continued for 3 hours whilst polymerization of the
emulsion particles occurred.
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Upon completion of the polymerization, the pX
Gf tne emul~ion was adjusted to 9 with approximately
0,15 parts of a 28% ammonia solution.
0.05 parts of a bacteriaide and 1,96 parts of an
aqueous ammoniacal solution (pH 9~0) containing ~5%
of a styrene-maleic anhydride copolymer were added,
~he size range of the polymer beads so-produced was
estimated at 10-40 micron,
Clear Bead Slurr~ 2-10 micron,
~he slurry was prepared as follows:
~ o a solution of 0,33 parts of hydroxyethyl
cellulose in 35,11 parts of water, 11,17 parts of a ~/2%
solution in water of an 80% hydrolysed polyvinyl alcohol
was added and stirred,
A solution Or 30,83 parts of an unsaturated
polyester resin and 1,12 parts of a 50% benzoyl
peroxide paste in 5,10 parts of styréne was added to
the above aqueous solution and mixed at high speed
until the largest emulsion particle visible under a
microscope was 10 micron diameter,
~ he emulsion was stirred slowly and 14 parts of
water and 0.18 parts of diethyl aniline were added.
~he slow stirring was continued for ~ hours whilst
polymerization of the emulsion particles occurred,
Upon completion of polymerization, the pX of the
emulsion was adJusted to 9 with approximately 0,15 pa~t~
of a 28% ammonia solution .
0.05 parts of a bactericide and 1.96 parts of an
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aqueous ammoniacal solution (pH 9.0) containing ~5% ~'
of a styrene-maleic anhydride copolymer were added. -
The size-range of the polymer beads so-produced
was estimated to be 2-10 micron.
White Bead ,Slurryl 10~0 micron.
~ he slurry was prepared as follows:
A solution of 8.51 parts of a 2.5% hydroxyethyl
cellulose solution and 8.51 parts of a 7.5% solution of
an 80% hydrolysed polyvinyl alcohol in 35.70 parts of'
water was formed. 16.20 parts of a rutile titanium
dioxide pigment was dispersed by high speed mixing
to a fineness of less than 2 micron Hegma~n in a
solution of 23.50 parts of an unsaturated polyester ir
~.70 parts of styrene. A mixture of 0.85 parts of a
5% benzoyl peroxide paste and 1.02 parts of divinyl
benzene was added to the above dispersion. ~he
resulting mixture was addèd to the above aqueous
solution and mixe~ at high speed until the largest
emulsion particle visible under a microscope was
40 micron.
~ he emulsion was then stirred slowly and 0.22 parts
of diethyl aniline was added. ~he slow stirring was
continued for 1 hour whilst polymerization of the
emulsion particles occurred.
Upon completion of the polymerization, the pH
of the emulsion was adjusted to 9 with approximately
0.12 parts cf a 28% ammonia solution.
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0.04 paxts of a bactericide and 1.58 parts of
an aqueous ammoniacal solution (pH 9,0) containing 35%
of a styrene-maleic anhydride copolymer were added.
The size-range of the polymer beads ~o-produced was
estimated to be 10-40 micron.
~h_te Bead Slurxy~ 2-10 micron.
A solution of 9.20 parts of a 2.5% hydroxyethyl-
cellulose solution and 13.80 parts of a 7.5% solutio~
of a 80% hydrolysed po]y(vinyl alcohol) in 18.50 par'ss
of water was formed.
14~80 parts of a rutile titanium dioxide pigment
was dispersed by high speed mixing to a fineness of less
than 2 micron Hegmann in a so]ution of 21.30 parts Or
an unsaturated polyester resin in 3.40 parts of styreneO
0.75 parts of a 50% benzoyl peroxide pa~te was added
~o th~s dispersion. ~he resulting mixture was added
to the above aqueous so~ution and mixed at high speed
until the largest particle visible under a microscope
was 10 micron.
- 20 ~he emulsion was then stirred siowly and 15.70 parts
of water and 0~18 parts of diethylaniline were added.
The slow stirring was continued for 1 hour whilst
polymerization of the emulsion particles occurred.
Upon completion of polymerixation, the pH of the
emulsion was adjusted to 9 with approximately 0.90 parts
of a 28% ammonia solution.
0.03 parts of a bactericide and 1.44 parts of
an aqueous ammoniacal solution (pH 9.0) containing
35% of a styrene-maleic anhydride copolymer were added.
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~0~6178
The size-range of the polymer beads so-produced
was ~sti~lated to be 2-10 micro~.
The inv~nGion is illustxated by the following
examples in which al.l parts are given by weight:
~XAMP~E 1
A paint according to tha invention to be used as
a tinting base was made using high speed dispersion
equipment~ to the following formula.
Parts
~hite bead slurry~ 10-40 micron 35.6 :
white bead slurry~ 2-10 micron 29.2
ammonia solution (28% wt~ 0.5
rutile titanium dioxide pigment 13.0
polymeric thickener 0.8
dispersant solution 2.0
ooalesci.ng agent 0.4
acrylic aqueous emulsion
(50% solids, m~nimum filming
temperature 18 C; ~ukon hardness
1.0% ~article size approx.
0.2 micron)* 15.0
water 3.5
A suitable latex is, for example,"Rhoplex"AC~61 of
Rohm and Haas Co., U.S.A.(Registered trade marks)
~XAMP~ 2
A paint according to the invention to be used as
a tinting base was made, using high speed dispersion
equipment~ to the following formula
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Parts
clear bead slurry, 10-40 micron 32.0
white bead ~lurry, 2-10 micron 29.2
ammonia solution (28%) 0,5
rutile titanium dioxide pigment 13.0
polymerlc thickener 0.8
dispersant solution 2.0
coale~cing agent 0.4
acrylic emulsion as in Example 1 15 0
water 7.1
~he example was repeated replacing on solids t;h~
acry:Lic emulsion by an emulsion of vinyl acetate polymer
cons:isting of a copolymerised mixture of vinyl acetate
and 2-ethyl hexylacrylate in the proportion by weight; of
85/15
EXAMP~E 3
A paint according to the invention to be used
as a tinting base was made, using high speed dispersion
equipment, to the following formula:
Parts
clear bead slurry, 10-40 micron 32.0
clear bead slurry, 2-10 micron 26.1
ammonia (28%) o 5
rutile titanium dioxide pigment 13.0
polymeric thickener 0 8
dispersant solution 2.0
coalescing agent 0 4.
acrylic emulsion as in Example 1 15.0
water 10.2
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EXAMP~E 4
Colo1lrs were tinted from the mar resistant tint
base of Exa~ple 1 and applied to a test panel b;y
brushing. ~he dried films were examined for colour
unifoImity and degree of hiding.
Using a tinter eomprising a dispersion in a water-
compatible medium of a phthalocyanine blue pigment,
blue colours with a G reflectance (as hereinabove
defined) of less than 60% were prepared. They showed
an unacceptable degree of departure from eolour
uniformity, evident both as streakiness in the direc~io~
of brushing and so ealled "flip and flop" as herein-
above defined. All eolours were judged to be of
aeceptable hiding power when compared with flat paints
utilizing con~entional teehnolo~y.
Using a t.inter comprising a dispersion in a
water-eompatible medium of a red iron oxide pig~ent
pink eolours with a G refleetance of less than 60%
showed an unaeceptable degree of flip. lints of
greater than 60% G reflectance were acceptable with
regard to flip. All eolours were of aeeeptable hiding
power,
Using a tinter eomprising a dispersion in a water-
eompatible medium of a earbon black pigment~ gre~
colours with a G reflectance less than 66% showed an
unacceptable degree of flip. ~ints of greater than
66% G reflectance were acceptable with regard to flip~
All eolours were of acceptable hiding power.
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1046i78
EXAMPIJE 5
.
Co:Lo~rs were tinted ~rom the mar-resistant tint
base o.~ Example 2 and applied to a test panel by
brushing. ~he flried films were exam.ined for 'flip
and ~icling power.
Using a phthalocyanine blue tinter, blu.e tints
with a G reflectance le~s th~n 29% ~howed unacceptable
flipo Above a reflectance oP 29% the degree of flip
was acoeptable. Hiding power was judged to be
unacceptably low for colours with G reflectanoes
greater than 65%. Colours with G reflectances in
the range of 29% - 65% were acceptable with regard to
both flip and hiding power.
Similar behaviour was observed with other
coloured tinters~
h~AMP~
Colours were tinted from the mar resistant tint
base of Example 3 and applied to a test panel by
brushing~ The d~ied film were examined for 'flip' .,
and hiding power.
I~o tinted colours from this tint base showed
,
'flip'. ~he hiding power was acceptable only for
tints w~th G reflectances below 30%.
EXAMP~E 7
Demonstration of the effect of lowering the
proportion of beads to below 55% of the total volume
solids.
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1046i7~ ;
A paint suitable for use as a tinting base was
made, using high speed dispersion equipment, to the
following formula;
Parts
clear bead slurry~ 10-40 mic~ons 10 3
clear bead slurry, 2-10 microns 8 5
ammonia (28%) 0,5
rutile titanium dioxide pigment 13.0
polymeric thicken~r 0~8
dispersant solution 2.0
coalescing agent 004
acrylic emulsion as in Example 1 15.0
water oOg
In this tint base, the beads comprise 40%
f the volume of the solids in contrast to the 67% of
Example 3. ~he bead was tinted to give a G reflectance
of below 30% as des¢ribed in Example 6 and applied to
a test panel by brushing. On examination, it was ~-
found that the panel exhibited a high degree of
"~heeriness", a mottled appearance caused by the
presence of glossy patches and stre~ks on the film.
~he panel of the tint base of Example 3 described
in Example 6 dld not show these defects
. EXA~E 8
Demonstration of the effect of al'~ering the
xelative quantities of larger and smal~ler beadsv
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1046178
Two tint ba~e~ hereinafter referred to as (a) and
(b) were prepared according to the method and using
the materialR and quantities of Example 3 with the
exceptions that the quantities of beads used therein
were substituted by the following quantities:
(a) (b)
clear bead slurry, 10~40 micron 22.5 41.7
clear bead slurry~ 2-10 micron ~4.6 18.6
~he quantities of slurry comprise the same total
volume of beads as the quantities used in Example 3~
but in (a) the larger beads comprise 35% of the total
volume of beads, and in (b) they comprise 65% of the
total volume of beads. Both these lie outside the
required larger bead volume of 45-55% of the tot~al
bead volume in contrast to Example 3 wherein the larger
beads ¢omprise 50% of the total volume of beads,
~ he two tint bases were tinted as described in
Example 6 and then brushed out on to panels. ~he
film of the tinted base (~) showed unacceptable
"sheeriness" and the base (b) had acceptable
appearance but was very susceptible to marring and
abrading. The tinted base of Example 3 did not
exhibit either defect.
EXAMP~E 9
Preparation of a tint base utilising a non-
aqueous film-former.
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46~78
White bead slurIie~ of both 2~10 mit;ron and
10-~() micIon size ranges of beads were dried and the
resu~l.tant dried beads mixed so that beads of the
10-/-~-() micron ,si.ze range comprised 50% by volume of
the lnixed drit-~d beads.
10 par~s of rut:ile titanium dio~ide wer0
di~-:persed in 20 parts of a 40% solution in ~ylenti of
a soya bean oil/glycero1 phthalate alkyd of 50o
oil length. To this mixture, 5 parts of the dry
poly~ler beads and 10 parts of xylene were added and
the aggregates dispersed by sand-grinding the mixture,
~he resulting base was then filtered,
The base was tinted with a tinter comprising
a dispersion of phthalocya~i.ne blue in a xylene-
com~atible medium to give a range of tints and filmsof the paint so-prepared were applietl to test panels
by brushing~ It was found that blue colours with
G reflectances of over 60% showed act,eptable "flip"
but those with G reflectances below this were
unacceptable.
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