U.S. patent application number 10/159751 was filed with the patent office on 2002-12-19 for method for dispersing a hydrophobic additive in an aqueous media.
Invention is credited to Walker, Kenneth Raymond.
Application Number | 20020193477 10/159751 |
Document ID | / |
Family ID | 10856169 |
Filed Date | 2002-12-19 |
United States Patent
Application |
20020193477 |
Kind Code |
A1 |
Walker, Kenneth Raymond |
December 19, 2002 |
Method for dispersing a hydrophobic additive in an aqueous
media
Abstract
An aqueous composition and method for applying additives to
polymeric particles includes a water-dissipatable polyester derived
from a dicarboxylic acid component and a diol component and a
difunctional monomer containing a SO.sub.3M moiety attached to an
aromatic nucleus to at least partially disperse the additive. A
method for dispersing a hydrophobic additive in an aqueous media
includes the step of contacting the hydrophobic additive with an
effective amount of the water-dissipatable polyester to form a
mixture and agitating the mixture sufficiently to produce a
homogenous blend is also described.
Inventors: |
Walker, Kenneth Raymond;
(Billinge Wigan Lancs, GB) |
Correspondence
Address: |
Mark L. Davis
P.O. Box 9293
Gray
TN
37615-9293
US
|
Family ID: |
10856169 |
Appl. No.: |
10/159751 |
Filed: |
May 29, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10159751 |
May 29, 2002 |
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09602221 |
Jun 23, 2000 |
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6403677 |
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Current U.S.
Class: |
524/206 |
Current CPC
Class: |
C08J 2467/00 20130101;
C08J 3/226 20130101; C08J 3/2053 20130101 |
Class at
Publication: |
524/206 |
International
Class: |
C08K 005/16 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 28, 1999 |
GB |
9915039.3 |
Apr 14, 2000 |
GB |
PCT/GB00/01423 |
Claims
I claim:
1. An aqueous composition of matter comprising: a. an additive for
coating at least a portion of a polymeric particle; b. an effective
amount of a water-dissipatable polyester derived from a
dicarboxylic acid component and a diol component and a difunctional
monomer containing a SO.sub.3M group attached to an aromatic
nucleus to at least partially disperse said additive, wherein M is
selected from the group consisting of is hydrogen, Na.sup.+,
Li.sup.+, K.sup.+, Mg.sup.++, Ca.sup.++, Cu.sup.++, Fe.sup.++,
Fe.sup.+++, or a combination thereof.; and c. from about 5 weight %
to about 95 weight % water, wherein said percentages are based on
the total weight of the components a-c.
2. The composition of claim 1 wherein said effective amount of said
water-dissipatable polyester is from about 5 weight % to about 50
weight %.
3. The composition of claim 1 wherein said effective amount of said
water-dissipatable polyester is from about 15 weight % to about 50
weight %.
4. The composition of claim 1 wherein said effective amount of said
water-dissipatable polyester is from about 25 weight % to about 50
weight %.
5. The composition of claim 1 wherein said additive is selected
from the group consisting of antioxidants, coupling agents,
antistatic agents, nucleating agents, metal deactivators,
lubricants, slip agents, antiblocking agents, UV inhibitors, flame
retardants, release agents, pigments, colorants, acetaldehyde
reducing compounds, reheat aids, and mixtures thereof.
6. The composition of claim 5 wherein said additives are selected
from the group consisting of tetrakis[methylene 3-(3',
5'-di-tert-butyl-4'-hydroxy- phenyl)-propionate ]methane, octadecyl
3-(3', 5'-di-t-butyl-4-hydroxypheny- l)propionate,
1,3,5-trimethyl-2,4,6-tris-(3, 5-di-tert-butyl)-4-(hydroxybe-
nzyl)benzene, bis(2,4-di-t-butyl-phenyl) pentaerythritol
diphosphite, tris(mono nonylphenyl)phosphite, 4,4'-butylidene-bis
(5-methyl-2-t-butyl)phenol,
tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanur- ate,
tris-nonylphenyl phosphite; distearyl pentaerythritol diphosphite;
tetrakis-(2,4-di-t-butylphenyl)-4,4'-biphenylylene diphosphonite;
tris-(2,3-di-t-butylphenyl) phosphite; butylated hydroxy toluene;
dicetyl thiodipropionate; dimyristyl thiodipropionate; poly
(1,4-cyclohexylene-dimethylene-3,3 '-thiodipropionate (partially
terminated with stearyl alcohol); silanes; titanates; chromium
complexes; low molecular weight polyolefins (with carboxylic
moieties); high molecular weight polyolefins; acrylates (with
carboxylic moieties); chlorinated paraffins; glycerol
monostearates; ethyoxylated amines; polyethylene glycol;
quarternary ammonium compounds and its salts; sodium benzoate;
diphenyl phosphinic acid and salts of magnesium, sodium, calcium,
aluminum; phenyl phosphinic acid and its salts; phenyl phosphorous
acid and its salts; oxalyl bis-(benzylidene hydrazide);
2,2'-oxamido bis-(ethyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)
propionate; diatomaceous silica; precipitated silica, silica gel,
talc; clay; metallic stearates; alkyl bis-stearamids; glycerol
monostearates; polyethylene glycol; crucamid; oleamid,
2-hydroxy-4-octoxybenzophenone; 2-hydroxy-4-isooctoxybenzophenone;
4-hydroxy-4-n-dodecyloxybenzophenone;
2-(3-di-t-butyl-2-hydroxy-5-methylphenyl-5-chlorobenzotriazole;
2-(2-hydroxy3,5-di-t-amylphenyl) benzotriazole; p-t-butylphenyl
salicyllate; 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate;
nickel bis-ortho-ethyl(3,5-di-t-butyl-4-hydroxybenzyl) phosphonate;
2,2', 6,6'-tetramethyl-4-piperidinyl sebacate, decabromodiphenyl
oxide; dodecachlorodimethane dibenzocyclooctane; ethylene
bis-dibromo norbornane dicarboximide; ethylene
bis-tetrabromophthalimide; antimony trioxide, methyl paraben, ethyl
paraben, propyl paraben, halogenated alkyl organic compounds,
polyamides, carbon black, antomony metal, infrared absorbing
compounds, and mixtures thereof.
7. The composition of claim 1 wherein said additives range from
about 0.5 weight % to about 35 weight %.
8. The composition of claim 1 wherein said additives range from
about 2 weight % to about 30 weight %.
9. The composition of claim 1 wherein said additives range from
about 5 weight % to about 25 weight %.
10. The composition of claim 1 wherein said polymeric particle has
a surface energy of from about 25 dynes/cm to about 45
dynes/cm.
11. A method for applying additives to polymeric particles
comprising the step of contacting said particles with the
composition of claim 1.
12. The method of claim 11 further comprising drying the resulting
particles.
13. The method of claim 11 wherein said polymeric particle has a
surface energy of from about 25 dynes/cm to about 45 dynes/cm.
14. The method of claim 11 wherein said polymeric particle has a
surface energy of from about 25 dynes/cm to about 40 dynes/cm.
15. The method of claim 11 wherein said polymeric particle has a
surface energy of from about 25 dynes/cm to about 35 dynes/cm.
16. The method of claim 10 wherein said polymeric particle is
selected from the group consisting of polyolefins selected from the
group consisting of polypropylene, low density polyethylene, high
density polyethylene and linear low density polyethylenes,
polystyrene, polyesters, polyamides; copolymers selected from the
group consisting of crystalline propylene ethylene copolymers;
rubber and mixtures thereof.
17. A method for dispersing a hydrophobic additive in an aqueous
media comprising the step of contacting the hydrophobic additive
with an effective amount of the water-dissipatable polyester of
claim 1 to form a mixture; and agitating said mixture sufficiently
to produce a homogenous blend.
18. The method of claim 17 wherein said additive is selected from
the group consisting of antioxidants, coupling agents, antistatic
agents, nucleating agents, metal deactivators, lubricants, slip
agents, antiblocking agents, UV inhibitors, flame retardants,
release agents, pigments, colorants, acetaldehyde reducing
compounds, reheat aids, and mixtures thereof.
19. The method of claim 17 wherein said additive ranges from about
0.5 weight % to about 35 weight % of said blend.
20. The method of claim 17 further comprising contacting a
polymeric particle having a surface energy of from about 25
dynes/cm to about 45 dynes/cm with said blend.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit to international application
PCT/GB00/01423 filed Apr. 14, 2000 which claims priority to United
Kingdom application 9915039.3 filed Jun. 28, 1999.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to the aqueous application of
additives to polymeric particles. Particularly, the invention
relates to a composition and a method for applying additives to
polymeric particles. More particularly, the composition and method
for applying additives to polymeric particles includes using a
water-dissipatable polyester derived from a dicarboxylic acid
component and a diol component and a difunctional monomer
containing a SO.sub.3M moiety attached to an aromatic nucleus. The
composition and method of the invention are particularly suited for
applying hydrophilic and/or hydrophobic materials to polymeric
particles.
[0003] Numerous methods for introducing additives to polymeric
particles are known to those skilled in the art. For example,
additives such as antioxidants, processing aids, slip agents,
antiblocking agents, antistatic agents, lubricants, UV stabilizers,
coupling agents and colorants can be dry blended in either pellet
or powder form or melt blended using an extruder or other suitable
melt blending apparatus.
[0004] Some polymers are presently being manufactured with
technology that does not lend itself to such techniques as melt
compounding and pelletizing. Many polymers such as high density
polyethylene, linear low density polyethylene, and polypropylene
emerge from the polymerization reactor in a dry granular form,
i.e., in a form similar to that of a fluidized bed system.
Presently, additives for these polymers must be introduced by
melting, compounding, and then pelletizing. This extra step
increases the cost of such polymer manufacturing operations and can
adversely affect the properties of such polymers.
[0005] Another method of introducing additives to polymeric
particles is to contact such particles with an additive at the
extruder hopper during end use processing, but before melt
compounding or extrusion. Additives such as colorants, slip agents,
processing aids, blowing agents, and others are introduced to
virgin polymeric particles at this stage usually in concentrate
form. In many instances, difficulty is encountered in metering the
exact amounts of additive concentrate necessary to do a specific
job. This is especially true for additives such as processing aids
and external lubricants which are used at very low levels and
usually cannot be added in a concentrate form.
[0006] Another method for coating polymeric particles, particularly
polypropylene granules, with additives includes dispersing the
additives in a solvent followed by removal of the solvent. While
some stabilization is imparted to the coated polypropylene
granules, the treated pellets have severe static electricity
problems when subsequently processed.
[0007] It would be desirable to have available a simple process for
applying additives to polymeric particles in order to enhance the
stability of the particles without adversely affecting the physical
properties and processability of the treated particles.
SUMMARY OF THE INVENTION
[0008] In accordance with the present invention, a wide range of
additives, such as antioxidants or thermal stabilizers, colorants
or the like can be applied to the surface of polymeric particles.
Advantageously, the additives may be emulsified or dispersed in an
aqueous system and used to coat the polymeric particles before
normal drying or degassing operations. The additives may be applied
using a variety of techniques such as, for example employing a
spray, wipe, or dip system. Such aqueous systems may be formulated
to treat polymeric particles which can then be formed into
materials made from such particles. The resulting materials may be
used in applications such as film or packaging for food, medicine
and the like. Also, such aqueous systems may contain lubricants,
mold release agents, antistatic agents and the like.
[0009] Briefly, the present invention includes an aqueous
composition includes an additive, an effective amount of a
water-dissipatable polyester, and from about 15 to about 95 30
weight % water.
[0010] Another aspect of the present invention is a method for
applying various additives to a polymeric particle. The method
includes the steps of contacting at least a portion of the polymer
with the composition of the present invention having at least one
additive included therein and drying the polymeric particles
whereby at least a portion of the additive is retained on the
polymeric particle.
[0011] Polymers which emerge from the polymerization reactor in
particle form would substantially benefit from the application of
such aqueous emulsions containing antioxidants and other additives
by means of such an aqueous treatment. This means of introducing
additives would eliminate melt compounding, lower production energy
requirements, and minimize heat history on the polymer
particles.
DETAILED DESCRIPTION OF THE INVENTION
[0012] In accordance with the present invention, an aqueous
composition is provided for applying a variety of additives to
polymeric particles. The aqueous composition includes at least one
additive, an effective amount of a water-dissipatable polyester
derived from a dicarboxylic acid component and a diol component and
a difunctional monomer containing a -SO.sub.3M group attached to an
aromatic nucleus to at least partially disperse the additive, and
from about 5 weight % to about 95 weight % water, wherein the
percentages are based on the total weight of the components in the
aqueous composition.
[0013] Additives employed in the practice of the present invention
include such materials as antioxidants, including, for example,
hindered phenols, thioesters, organophosphites, and hindered
amines, which may readily be dispersed or emulsified in the aqueous
emulsion system. Additional additives contemplated by the present
invention include coupling agents, antistatic agents, nucleating
agents, metal deactivators, lubricants, slip agents, antiblocking
agents, UV inhibitors, flame retardants, release agents, pigments,
colorants, acetaldehyde reducing compound, reheat aids, and the
like. More particularly, the additives employed in the practice of
the present invention maybe selected from antioxidants, e.g.,
tetrakis[methylene 3-(3',
5'-di-tert-butyl-4'-hydroxyphenyl)-propio- nate]methane, octadecyl
3-(3', 5'-di-t-butyl-4-hydroxyphenyl)propionate,
1,3,5-trimethyl-2,4,
6-tris-(3,5-di-tert-butyl)-4-(hydroxybenzyl)benzene, bis
(2,4-di-t-butyl- phenyl) pentaerythritol diphosphite, tris(mono
nonylphenyl)phosphite,
4,4'-butylidene-bis(5-methyl-2-t-butyl)phenol,
tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, tris-nonylphenyl
phosphite; distearyl pentaerythritol diphosphite;
tetrakis-(2,4-di-t-buty- lphenyl)-4,4'-biphenylylene-diphosphonite;
tris-(2,3-di-t-butylphenyl) phosphite; butylated hydroxy toluene;
dicetyl thiodipropionate; dimyristyl thiodipropionate; poly
(1,4-cyclohexylene-dimethylene-3,3'-thi- odipropionate (partially
terminated with stearyl alcohol); and the like; coupling agents,
e.g., silanes; titanates; chromium complexes; low molecular weight
polyolefins (with carboxylic moieties); high molecular weight
polyolefins and acrylates (with carboxylic moieties); chlorinated
paraffins; and the like; antistatic agents, e.g., glycerol
monostearates; ethyoxylated amines; polyethylene glycol;
quarternary ammonium compounds (salts); and the like; nucleating
agents, e.g., sodium benzoate; diphenyl phosphinic acid (including
magnesium, sodium, calcium, aluminum salts); phenyl phosphinic acid
(including salts); phenyl phosphorous acid (including salts); and
the like; metal deactivators, e.g., oxalyl bis-(benzylidene
hydrazide); 2,2 '-oxamido bis-(ethyl
3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate; and the like;
lubricants/slip agents/antiblocking agents, e.g., diatomaceous
silica (earth); precipitated silica, silica gel, talc; clay;
metallic stearates; alkyl bis-stearamids; glycerol monostearates;
polyethylene glycol; erucamid; oleamid, and the like; UV
inhibitors, e.g., 2-hydroxy-4-octoxybenzophenone; 2-hydroxy-4
-isooctoxybenzophenone; 4-hydroxy-4-n-dodecyloxybenzophenone; 2-(3
-di-t-butyl-2-hydroxy-5-methyl- phenyl-5 -chlorobenzotriazole;
2-(2-hydroxy-3,5-di-t-amylphenyl) benzotriazole; p-t-butylphenyl
salicyllate; 2,4-di-t-butylphenyl-3,5-di-t-
-butyl-4-hydroxybenzoate; nickel
bis-ortho-ethyl(3,5-di-t-butyl-4-hydroxyb- enzyl) phosphonate;
2,2', 6,6'-tetramethyl-4-piperidinyl sebacate, and the like; flame
retardants, e.g., decabromodiphenyl oxide; dodecachlorodimethane
dibenzocyclooctane; ethylene bis-dibromo norbornane dicarboximide;
ethylene bis-tetrabromophthalimide; antimony triokide, and the
like; biocides, e.g., methyl paraben, ethyl paraben, propyl
paraben, halogenated alkyl organic compounds, transition metal
carbamate salts, and the like; acetaldehyde reducing compounds such
as polyamides, such as those disclosed in U.S. Pat. Nos. 5,650,469;
5,258,233; and 5,340,884, and reheat aids such as carbon black,
antimony metal and IR absorbing dyes, such as those disclosed in
the PCT publication U.S. 97/15351, the entire disclosures of each
being incorporated herein by reference, as well as mixtures of any
two or more of the above mentioned classes of compounds, or
mixtures of two or more compounds from within a given class of
compound.
[0014] The additives are present in the composition ranging from
about 0.5 weight % to about 35 weight %, desirably from about 2
weight % to about 30 weight % and more desirably from about 5
weight % to about 25 weight %, based on the total weight of the
constituents of the composition of the invention. The above
additives are desirably used to coat the polymer particles in
amounts ranging from about 10 ppm to about 20,000 ppm (2 weight %)
and preferably from about 500 ppm to about 10,000 ppm (1 weight %)
based on the total weight of the polymer.
[0015] One skilled in the art would understand the term
"antiblocking" as used herein to denote tacky homopolymeric or
copolymeric materials that tend to block, adhere or congeal
together in a nonpermanent but relatively strong bond after the
materials have been formed into discrete particles or films and are
placed in a face-to-face contact. Depending on the tackiness of the
surface, the bond may be the result of time, pressure and
temperature or any combination thereof. Depending upon the targeted
end use of the polymer, it is probable that tackifying additives
have been utilized to improve the cling properties of a film made
from the polymer. Such additives include polybutenes terpene
resins, alkali metal stearates and hydrogenated rosins and rosin
esters.
[0016] The water-dissipatable polyester is essentially derived from
the following components: A) at least one dicarboxylic acid; B) at
least one diol where at least 20 mole percent of the diol is
composed of an ethylene glycol having the formula
H(OCH.sub.2CH.sub.2).sub.nOH where n is an integer of from two to
about twenty; and C) at least one difunctional dicarboxylic acid
sulfomonomer containing a -SO.sub.3M group attached to an aromatic
nucleus, wherein M is hydrogen or Na.sup.+, Li.sup.+, K.sup.+,
Mg.sup.++, Ca.sup.++, Cu.sup.++, Fe.sup.++, F.sup.+++ or a
combination thereof. The sulfomonomer component of the polyester
constitutes from about 8 mole percent to about 45 mole percent of
the total moles in constituents A-C. Such water-dissipatable
polyesters are described in greater detail in U.S. Pat. Nos.
3,546,008 issued to Shields et al. and 3,779,993 issued to Kibler
et al., the entire disclosures of which are incorporated herein by
reference.
[0017] Generally, the dicarboxylic acid component of the
water-dissipatable polyester can be any aliphatic, cycloaliphatic,
or aromatic acid. Examples of such dicarboxylic acids include
oxyalic; malonic; dimethylmalonic; succinic; glutaric; adipic;
trimethyladipic; pimelic; 2,2-dimethylglutaric; azelaic; sebacic;
fumaric; maleic; itaconic; 1,3-5 cyclopentanedicarboxylic;
1,2-cyclohexanedicarboxylic; 1,3-cyclohexanedicarboxylic;
1,4-cyclohexanedicarboxylic; phthalic terephthalic; isophthalic;
2,5-norbomanedicarboxylic; 1,4-naphthalic; diphenic;
4,4'-oxydibenzoic; diglycolic; thiodipropionic;
4,4'-sulfonyldibenzoic; and 2,5-naphthalenedicarboxylic acids.
[0018] It should be understood that the use of the corresponding
acid anhydrides, esters, and acid chlorides of these acids are
included in the term "dicarboxylic acid". The esters are preferred,
examples of which include dimethyl 1,4-cyclohexanedicarboxylate;
dimethyl 2,6-naphthalene dicarboxylate; dibutyl
4,4'-sulfonyldibenzoate; dimethyl isophthalate; dimethyl
terephthalate; and diphenyl terephthalate. Copolyesters may be
prepared from two or more of the above dicarboxylic acids or
derivatives thereof.
[0019] At least 20 mole percent of the diol component used in
preparing the linear water dissipatable polyester is a
poly(ethylene glycol) having the formula
H(OCH.sub.2CH.sub.2).sub.nOH where n is an interger of from two to
about twenty. Examples of preferred poly(ethylene glycols) include
diethylene, triethylene, tetraethylene, pentaethylene,
hexaethylene, heptaethylene, octaethylene, nonaethylene,
decaethylene glycols and mixtures thereof. The remaining portion of
the diol component is at least one aliphatic, cycloaliphatic, or
aromatic diol. Examples of these diols include ethylene glycol;
propylene glycol, 1,3 -propanediol;
2,4-dimethyl-2-ethylhexane-1,3-diol; 2,2 -dimethyl-1,3-propanediol;
2-ethyl-2-butyl- 1,3-propanediol; 2-ethyl-2-isobutyl-
1,3-propanediol; 1,3-butanediol; 1,4 -butanediol; 1,5-pentanediol;
1,6-hexanediol; 2,2,4-trimethyl-1,6 -hexanediol; 1,2-25
cyclohexane-dimethanol; 1,3-cyclohexanedimethanol;
1,4-cyclohexane-dimethanol;
2,2,4,4-tetramethyl-1,3-cyclobutanediol; and p-xylylenediol.
[0020] The third constituent of the water-dissipatable polyester is
a difunctional monomer containing a -SO.sub.3M group attached to an
aromatic nucleus, wherein M is hydrogen or a metal ion and may be
added directly to the reaction mixture from which the polyester or
polyesteramide is made. This difunctional monomer component may be
either a dicarboxylic acid, or derivative thereof, containing a
-SO.sub.3M group or a diol containing a -SO.sub.3M group. The metal
ion of the sulfonate salt group may be Na.sup.+, Li.sup.+, K.sup.+,
Mg.sup.++, Ca.sup.++, Cu.sup.++, Fe.sup.++, Fe.sup.+++ or
combinations thereof. The -SO.sub.3M moiety is attached to the
aromatic nucleus, examples of which include benzene, naphthalene,
anthracene, diphenyl, oxydiphenyl, solfonyldiphenyl, and
methylenediphenyl.
[0021] The amount of water-dissipatable polyester present in the
composition of the invention can range from about 5 weight % to
about 50 weight %, preferably from about 15 weight % to about 50
weight % and more preferably from about 25 weight % to about 50
weight %., based on the total weight of the constituents in the
composition.
[0022] One skilled in the polyester art will understand that by
changing the proportions of the various acids which make up the
dicarboxylic acid component of the polyester or polyesteramide, the
properties of the polymer may be varied to meet specific end uses.
For example, as the proportion of terephthalic acid is decreased,
the polymer becomes more flexible. Moreover, varying the mole
percentages of sulfonate-containing difunctional monomer varies the
water susceptibility of the polymer.
[0023] The amount of water used to form the aqueous composition is
from about 5 weight % to about 95 weight % and preferably from
about 10 weight % to about 90 weight % and more preferably from
about 10 weight % to about 85 weight %, based on the total weight
of the constituents in the aqueous composition. The water used to
form the composition may further contain additives such as
antioxidants, processing aids, slip agents, antiblocking agents,
lubricants and the like that, preferably, are hydrophilic.
[0024] Some preferred polymeric particles which may be coated using
the composition and method of the present invention include, for
example, polyolefins such as crystalline polypropylene, low density
polyethylene, high density polyethylene and linear low density
polyethylenes. Other polymeric materials include, for example,
polystyrene, polyesters, polyamides and the like as well as
copolymers such as crystalline propylene ethylene copolymers,
rubbers such as ethylene propylene rubber and the like. The
polymeric particles suitable for being contacted with the aqueous
composition of the present invention can be in the form of beads,
powder, pellets and the like.
[0025] Advantageously, and quite unexpectedly, the composition of
the present invention allows the coating of polymeric particles
using an aqueous dispersion for hydrophobic materials.
Additionally, the aqueous composition and method of the invention
may be used to coat materials having a surface energy from about 25
to about 45 dynes/cm. Preferably, the aqueous composition and
method of the invention may be used to coat materials having a
surface energy from about 25 to about 40 dynes/cm, and more
preferably from about 25 dynes/cm to about 35 dynes/cm.
[0026] In accordance with another embodiment of the present
invention, there is provided a method for applying additives to
polymeric particles. The method includes the steps of contacting
the particles with the above-described composition having at least
one additive and optionally drying the resulting particles.
[0027] In accordance with another embodiment of the invention there
is provided a method for dispersing a hydrophobic additive in an
aqueous media. The method includes the steps of providing and
contacting the hydrophobic additive with an effective amount of the
water-dissipatable polyester described above to form a mixture and
agitating the mixture sufficiently to produce a homogenous
blend.
[0028] The aqueous composition of the present invention can be
dispersed in an aqueous media in large quantities, upwards of about
50 weight % solids. Preferred loading levels fall in the range of
about 5 weight % to about 25 weight % based on the total weight of
the polymer additives and aqueous media. Typically, the loading
level is from sufficient to impart from about 500 ppm to about 1
weight % of the additive onto the polymeric particles.
[0029] The invention can be further illustrated by the following
non-limiting examples. It will be understood that these examples
are included merely for purposes of illustration and are not
intended to limit the scope of the invention unless otherwise
specifically indicated.
[0030] These experiments use an aqueous dispersion or emulsion to
allow a water insoluble hydrophobic solid to be incorporated into
water to form a stable dispersion. If the stabilizing emulsion or
dispersion was not present, the insoluble solid would be mixed into
the water but would rapidly separate to form a distinct layer. The
percentages are by weight unless otherwise specified.
COMPARATIVE EXAMPLE 1
[0031] In an appropriate container, a homogenous additive blend was
prepared by mixing together the constituents of Table 1 below and
in the amounts shown. The constituents were blended using a high
speed Ultra Turrax mixer, available from IKA Werke, Janke &
Kunkel GmbH & Co. Staufen, Germany.
1 TABLE 1 Amount Ingredient (weight %) Wax Emulsion.sup.1 27.0
Pharmasorb Regular 40.0 Tergitol 15-S-7.sup.2 1.5 Span 60.sup.3 0.5
SE21 antifoam.sup.4 0.3 Amerstat 251.sup.5 0.08 Aerosol OT 70
PG.sup.6 1.0 Water 29.62 .sup.1The wax emulsion was prepared
according to the method described in U.S. Pat. No. 4,880,470,
Example 1. This consisted of 40 parts by weight of a low molecular
weight oxidised polyethylene wax having an acid number of about
15-17, 11 parts by weight Tergitol 15-S-9 from Union Carbide, 0.9
parts by weight of potassium hydroxide (86%), 0.4 parts by weight
sodium metabisulfite, and 150 parts by weight of water.
.sup.2Tergitol 15-S-7 is available from Union Carbide, USA.
.sup.3Span 60 is available from ICI, UK. .sup.4SE21 is available
from Wacker, Germany. .sup.5Amerstat 251 is available from Ameroid,
UK. .sup.6OT 70 PG is available from Cytec, France.
[0032] To evaluate the efficacy of the blend in applying an
additive to the surface of a polymer, a Kaolin clay based organic
filler, Pharmasorb Regular (available from Lawrence Industries, UK)
was used as an antiblocking additive. This material was chosen for
the evaluation since it is brown in color and would allow visual
appraisal of the coating efficiency on the polymer surface.
[0033] Five hundred grams (500g.) of polyethylene vinylacetate,
available from Bayer Germany, in the form of pastilles having a
diameter of about 5 mm was cleaned of any silica antiblocking
coating using detergent and water. The cleaned polyethylene
vinylacetate was dried and placed into a polyethylene bag.
Approximately 12.5 grams of the blend of Table 1 was poured into
the polyethylene bag to give an additive add-on of about 10,000 ppm
(1weight %). The bag was sealed, shaken by hand for 30 seconds to
mix the polymer and mixture. The coated polymer was poured into, a
porous tray and allowed to dry at room temperature.
[0034] After drying, the polymer was evaluated over a period of
several days to determine if the pastilles were free flowing (in
which case the anti-blocking additive formulation was successful)
or whether the pastilles has stuck together (in which case the
anti-blocking formulation was unsuccessful). The coating efficiency
of this blend was found to be unacceptable.
EXAMPLE 1
[0035] In accordance with the present invention, the procedure of
Comparative Example 1 above was repeated except the constituents of
the additive blend were those in Table 2 and in the amounts
shown.
2 TABLE 2 Amount Ingredient (weight %) AQ29D.sup.1 30.0 Pharmasorb
Regular 30.0 Water 40.0 .sup.1AQ29D is a sulfopolyester available
from Eastman Chemical Company, Kingsport, Tennessee, United States
of America.
[0036] After drying, the polymer was evaluated over a period of
several days to determine if the pastilles were free flowing (in
which case the anti-blocking additive formulation was successful)
or whether the pastilles has stuck together (in which case the
anti-blocking formulation was unsuccessful). The coating efficiency
of this blend was found to not reach the required standard.
Although the antiblocking effectiveness of both coatings were not
acceptable, the AQ29D sample was significantly better than the
coating of Comparison Example 1. The pastilles exhibited improved
flow and anti-sticking properties when measured over a storage
period of several weeks.
COMPARISON EXAMPLE 2
[0037] In an appropriate container, a homogenous additive blend was
prepared by mixing together the constituents of Table 3 below and
in the amounts shown. The constituents were blended using a high
speed Ultra Turrax mixer.
3 TABLE 3 Amount Ingredient (weight %) Wax Emulsion 27.0 Synpro 15
Calcium Stearate.sup.1 40.0 Tergitol 15-S-7 1.5 Span 60 0.5 SE21
antifoam 0.3 Amerstat 251 0.08 Aerosol OT 70 PG 1.0 Water 29.62
.sup.1Synpro 15 Calcium Stearate is available from Witco, USA.
[0038] Synpro 15 calcium stearate was used as an antiblocking
additive to coat 500g. of polyethylene vinylacetate prepared as
described above in Comparative Example 1. The blend of Table 3 was
poured into the polyethylene bag to give an additive add-on of
about 5,000 ppm. The bag was sealed, shaken by hand for 30 seconds
to mix the polymer and mixture. The coated polymer was poured into
a porous tray and allowed to dry at room temperature.
[0039] After drying, the polymer was evaluated over a period of
several days. It was found that at additive levels of 5,000 ppm,
the pastilles coalesced and were not easily separated from each
other. At an increased loading of 10,000 ppm, the pastilles were
free flowing without evidence of sticking and coalescence.
COMPARATIVE EXAMPLE 3
[0040] The additive blend of Comparative Example 2 was used to coat
polybutadiene, obtained from Repsol, Spain. The polybutadiene was
prepared by cutting a block of the material into cubes of
approximately 5 mm in size. The polybutadiene cubes were coated
with the additive blend of Table 3 in the manner described above in
Comparative Example 2 to give an additive add-on of about 5,000
ppm.
[0041] After drying, the polymer was evaluated over a period of
several days. It was found that the polymer cubes has coalesced
into one continuous mass indicating that the formulation shown in
Table 3 was inefficient as an anti blocking formulation on
polybutadiene.
EXAMPLES 2 and 3
[0042] In accordance with the present invention, a homogenous
additive blend was prepared by mixing together the constituents of
Table 4 below and in the amounts shown. The constituents were
blended using a high speed Ultra Turrax mixer.
4 TABLE 4 Amount Ingredient (weight %) AQ29D 22.5 Synpro 15 Calcium
Stearate 30.0 Water 47.5
[0043] The additive blend was used to coat polyethylene
vinylacetate and polybutadiene prepared as described above,
respectively. The polyethylene vinylacetate and polybutadiene
coated with the additive blend of Table 4 in the manner described
above in Comparative Example 2 to give an additive add-on of about
5,000 ppm.
[0044] After drying, the polymers were evaluated over a period of
several days and were found to be free flowing and consisting of
separate non-sticky particles.
[0045] From the examples it is apparent that the additive
compositions based on the sulfopolyester gave improved results
compared to the emulsifiable wax based formulations.
[0046] Although the present invention has been described in terms
of the presently preferred embodiment, it is to be understood that
such disclosure is not to be interpreted as limiting to the
invention described herein. No doubt that after reading the
disclosure, various alterations and modifications will become
apparent to those skilled in the art to which the invention
pertains. It is intended that the appended claims be interpreted as
covering all such alterations and modifications as fall within the
spirit and scope of the invention.
* * * * *