U.S. patent application number 09/816735 was filed with the patent office on 2002-07-25 for proteins and polymers for use as pitch and stickies control agents in pulp and papermaking processes.
Invention is credited to Gu, Qu-Ming, Nguyen, Duy T..
Application Number | 20020096293 09/816735 |
Document ID | / |
Family ID | 22705952 |
Filed Date | 2002-07-25 |
United States Patent
Application |
20020096293 |
Kind Code |
A1 |
Nguyen, Duy T. ; et
al. |
July 25, 2002 |
Proteins and polymers for use as pitch and stickies control agents
in pulp and papermaking processes
Abstract
Methods for inhibiting the depositions of organic contaminants
from pulp in pulp and papermaking systems are disclosed. A
combination of a protein and a cationic polymer is added to the
pulp or applied to deposition prone surfaces of a papermaking
system.
Inventors: |
Nguyen, Duy T.; (Austin,
TX) ; Gu, Qu-Ming; (Hockessin, DE) |
Correspondence
Address: |
POTTER ANDERSON & CORROON LLP
ATTN: KATHLEEN W. GEIGER, ESQ.
P.O. BOX 951
WILMINGTON
DE
19899-0951
US
|
Family ID: |
22705952 |
Appl. No.: |
09/816735 |
Filed: |
March 22, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60191556 |
Mar 23, 2000 |
|
|
|
Current U.S.
Class: |
162/174 ;
162/168.1 |
Current CPC
Class: |
D21H 21/02 20130101;
D21C 9/086 20130101; Y10S 162/04 20130101 |
Class at
Publication: |
162/174 ;
162/168.1 |
International
Class: |
D21H 017/22; D21H
017/34 |
Claims
What is claimed is:
1. A method of inhibiting the deposition of organic contaminants in
pulp and papermaking systems comprising adding to the pulp and
paper making system an effective deposition inhibiting amount of at
least one protein and at least one cationic polymer.
2. The method of claim 1 wherein the protein is selected from the
group consisting of whey protein.
3. The method of claim 1, wherein the cationic polymer is selected
from the group consisting of cationic starch, cationic
polyacrylamide, alum, cellulose derivatives, condensation polymers
produced from aliphatic amines and epichlorohydrin, polyamide amine
condensate, polyamide-amine-epichlorhydrin resins, polyethylene
imine, polyethylene oxide, polydiallyl-dimethyl-ammonium chloride,
melamine-formaldehyde resin and mixtures thereof.
4. The method of claim 1, wherein at least one cationic polymer
comprises poly diallydimethyl ammonium chloride.
5. The method of claim 1 wherein the organic contaminants are
stickies deposits.
6. The method of claim 1 wherein the organic contaminants are pitch
deposits.
7. A method of inhibiting the deposition of organic contaminants on
the surfaces of papermaking machinery and equipment in pulp and
papermaking systems comprising applying to the surfaces an
effective inhibiting amount of at least one protein and at least
one cationic polymer.
8. The method of claim 7, wherein the cationic polymer is selected
from the group consisting of cationic starch, cationic
polyacrylamide, alum, cellulose derivatives, condensation polymers
produced from aliphatic amines and epichlorohydrin, polyamide amine
condensate, polyamide-amine-epichlorhydrin resins, polyethylene
imine, polyethylene oxide, polydiallyl-dimethyl-ammonium chloride,
melamine-formaldehyde resin and mixtures thereof.
9. The method of claim 7, wherein at least one cationic polymer
comprises poly diallydimethyl ammonium chloride.
10. The method of claim 7 wherein the protein is selected from the
group consisting of whey protein.
11. The method of claim 7 wherein the organic contaminants are
stickies deposits.
12. The method of claim 7 wherein the organic contaminants are
pitch deposits.
Description
[0001] This application claims the benefit of U. S. Provisional
Application No. 60/191,556 filed Mar. 23, 2000.
FIELD OF THE INVENTION
[0002] The present invention relates to methods for inhibiting the
deposition of organic contaminants in pulp and papermaking
systems.
BACKGROUND OF THE INVENTION
[0003] The deposition of organic contaminants (i.e., pitch and
stickies) on surfaces in the papermaking process is well known to
be detrimental to both product quality and the efficiency of the
papermaking process. Some components occur naturally in wood and
are released during various pulping and papermaking processes. Two
specific manifestations of this problem are referred to as pitch
(primarily natural resins) and stickies (adhesives or coatings from
recycled paper). Pitch and stickies have many common
characteristics including: hydrophobicity, tackiness, low surface
energy, and the potential to cause problems with deposition,
quality, and efficiency in the process as mentioned above.
[0004] The term "pitch" can be used to refer to deposits composed
of organic constituents which may originate from these natural
resins, their salts, as well as coating binders, sizing agents, and
defoaming chemicals which may be found in the pulp. In addition,
pitch frequently contains inorganic components such as calcium
carbonate, talc, clays, titanium and related materials.
[0005] Stickies is a term that has been increasingly used to
describe deposits that occur in the systems using recycled fiber.
These deposits often contain the same materials found in "pitch"
deposits in addition to adhesives, hot melts, waxes, and inks. All
of the aforementioned materials have many common characteristics
including: hydrophobicity, defoamability, tackiness, low surface
energy, and the potential to cause problems with deposition,
quality, and efficiency in the process. Table I shows the complex
relationship between pitch and stickies discussed here.
1 TABLE I Pitch Stickies Natural Resins (fatty and resin acids,
fatty esters, X X insoluble salts, sterols, etc.) Defoamers (oil,
EBS, silicate, silicone oils, X X ethoxylated compounds, etc.)
Sizing Agents (Rosin size, ASA, AKD, hydrolysis X X products,
insoluble salts, etc.) Coating Binders (PVAC, SBR) X X Waxes X Inks
X Hot Melts (EVA, PVAC, etc.) X Contact Adhesives (SBR, vinyl
acrylates, X polyisoprene, etc.)
[0006] The deposition of organic contaminants, such as pitch and
stickies, can be detrimental to the efficiency of a pulp or paper
mill causing both reduced quality and reduced operating efficiency.
Organic contaminants can deposit on process equipment in
papermaking systems resulting in operational difficulties in the
systems. The deposition of organic contaminants on consistency
regulators and other instrument probes can render these components
useless. Deposits on screens can reduce throughput and upset
operation of the system. This deposition can occur not only on
metal surfaces in the system, but also on plastic and synthetic
surfaces such as machine wires, felts, foils, Uhle boxes and
headbox components.
[0007] Historically, the subsets of the organic deposit problems,
"pitch" and "stickies" have manifested themselves separately,
differently and have been treated distinctly and separately. From a
physical standpoint, "pitch" deposits have usually formed from
microscopic particles of adhesive material (natural or man-made) in
the stock which accumulate on papermaking or pulping equipment.
These deposits can readily be found on stock chest walls, paper
machine foils, Uhle boxes, paper machine wires, wet press felts,
dryer felts, dryer cans, and calendar stacks. The difficulties
related to these deposits included direct interference with the
efficiency of the contaminated surface, therefore, reduced
production, as well as holes, dirt, and other sheet defects that
reduce the quality and usefulness of the paper for operations that
follow like coating, converting or printing.
[0008] From a physical standpoint, "stickies" have usually been
particles of visible or nearly visible size in the stock which
originate from the recycled fiber. These deposits tend to
accumulate on many of the same surfaces that "pitch" can be found
on and causes many of the same difficulties that "pitch" can cause.
The most severe "stickies" related deposits however tend to be
found on paper machine wires, wet felts, dryer felts and dryer
cans.
[0009] Methods of preventing the build-up of deposits on the pulp
and paper mill equipment and surfaces are of great importance to
the industry. The paper machines could be shut down for cleaning,
but ceasing operation for cleaning is undesirable because of the
consequential loss of productivity, poor quality while partially
contaminated and "dirt" which occurs when deposits break off and
become incorporated in the sheet. Preventing deposition is thus
greatly preferred where it can be effectively practiced.
[0010] In the past stickies deposits and pitch deposits have
typically manifested themselves in different systems. This was true
because mills usually used only virgin fiber or only recycled
fiber. Often very different treatment chemicals and strategies were
used to control these separate problems.
[0011] Current trends are for increased mandatory use of recycled
fiber in all systems. This is resulting in a co-occurrence of
stickies and pitch problems in a given mill. It is desirable to
find treatment chemicals and strategies which will be highly
effective at eliminating both of these problems without having to
feed two or more separate chemicals.
[0012] It was suggested that gelatin could be used as a remedy for
pitch control. U.S. Pat. No. 5,885,419, the entire content of which
are wherein incorporated by reference discloses blood-related
proteins such as albumins and globulins for preventing
pitch/stickies deposition in the pulp and paper industry. However,
the milk protein used in the patent proved to be ineffective. The
patent does not reveal the physical/chemical properties of this
milk protein; however, its poor performance indicates the exclusion
of the high molecular weight whey proteins which surprisingly found
to be very effective in this invention.
BRIEF SUMMARY OF THE INVENTION
[0013] The present invention provides for compositions and methods
for inhibiting the depositions of organic contaminants from pulp
and papermaking systems
[0014] The present invention provides for methods for inhibiting
the deposition of organic contaminants, such as pitch and stickies,
in pulp and papermaking systems. The methods comprise adding to the
pulp or applying to the surfaces of papermaking machinery an
effective deposition inhibiting amount of a combination of a whey
protein and a cationic polymer.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The present invention relates to methods for inhibiting the
deposition of organic contaminants from pulp on the surface of
papermaking machinery in pulp and papermaking systems comprising
adding to pulp or applying to the surfaces of the paper making
machinery an effective deposition inhibiting amount of a whey
protein. The present invention provides for methods for inhibiting
the deposition of organic contaminants, such as pitch and stickies,
from pulp and papermaking systems.
[0016] Organic contaminants include constituents which occur in the
pulp (virgin, recycled or combinations thereof having the potential
to deposit and reduce paper machine performance or paper quality.
These contaminants include but are not limited to natural resins
such as fatty acids, resin acids, their insoluble salts, fatty
esters, sterols; and other organic constituents such as ethylene
bis-stearamide, waxes, sizing agents, adhesives, hot melts, inks,
defoamers, and latexes which may deposit in papermaking
systems.
[0017] There are two fundamentally different groups of proteins
present in milk, casein and whey. Casein proteins are heat
insensitive. Whey proteins are heat sensitive. Table I shows the
major differences in properties between casein and whey proteins,
including the major proteins in each group and their percentage
contribution to the total protein in milk.
2TABLE I Properties of Milk Proteins and Their Major Components
Protein Individual Protein in Type Structures and properties
Proteins milk % Casein Contains strongly hydrophobic
.alpha..sub.s-casein 45-55 regions, random coil structure
.beta.-casein 23-35 and little cysteine. Heat stable,
.kappa.-casein 8-15 but unstable in acidic conditions casein Whey
Contains both hydrophilic and .beta.-lactoglobulin 7-12 hydrophobic
residues, cysteine .alpha.-lactalbumin 2-5 and cystine, Globular
structure Proteose 2-6 with much helical content. Easily peptone
heat denatured. Stable in mildly Immuno- 2-3 acidic conditions
globulins Bovine Serum ca 1 Albumin
[0018] As can be seen, .beta.-lactoglobulin is the major component
of the whey protein. The average molecular weight of the whey
protein is from about 3000 to about 25,000.
[0019] As demonstrated in Table II, there are distinct differences
in the composition of proteins such as gelatin, serum albumin,
casein, and whey protein that can be seen in their amino acid
content.
3TABLE II Amino Acid Composition of Selected Proteins Serum Gelatin
(i.e., Albumin Whey (i.e., Casein (i.e., hydrolyzed (i.e., blood
Amino Acid milk protein) milk protein) collagen) protein) Alanine
3.3 2.8 7 0.6 Arginine 2.4 3.5 8 4.9 Aspartic Acid 10.3 6.6 6 9
Cystein 2.4 0.3 0.1 3.9 Glutamic Acid 16.6 20.3 10 15.6 Glycine 1.7
1.8 23 2.9 Histidine 1.9 2.7 0.7 3.1 Hydroxylysine -- -- 1 --
Hydroxyproline -- -- 12 -- Isoleucine 6.4 4.9 1 1.8 Leucine 9.9 8.7
3 11.3 Lysine 9.5 7.5 3 11.3 Methionine 2 2.6 0.8 1.2 Phenylalanine
3 4.8 2 6.4 Proline 6.1 10.6 15 6 Serine 5.1 5.6 3 4.3 Threonine
7.1 4.3 2 5.3 Tyrosine 2.9 5.3 0.4 3.5 Valine 6.1 6.2 2 8.8
Tryptophan 2 1.5 -- 0.2
[0020] Casein protein that is largely phosphorylated in its natural
form is much more hydrophilic than whey proteins, without being
bound by theory, it is theorized that the hydrophilicity may
prevent it from interacting with the hydrophobic stickies/pitch
particles and thereby, become an inefficient pitch/stickies control
agent. In contrast, similar to bovine serum albumin,
.beta.-lactoglobulin and .alpha.-lactalbumin, the major components
of whey protein apparently are more globular structurally than
casein since it has a higher content of cystein with which proteins
crosslink themselves through disulfide bonds. The globular
structure as well as the hydrophobicity of the whey protein
increases its interaction with the hydrophobic stickies and pitch
particles. Without being bound by theory, this may explain the
better performance of the whey protein when compared to casein.
Casein is more linear chemically because of lack of the disulfide
bonds in the protein. The whey proteins having molecular weights in
the range of at least about 3,000, preferably at least about 5000,
and even more preferably at least about 10,000 and up to about
30,000, more preferably up to about 25,000 and even more preferably
about 20,000, are useful in the present investigation. Whey protein
hydrolysate of the molecular weight less than 2,000 derived from a
protease-treatment did not show desired properties (Table III),
without wishing to be bound by theory, this is an indication that
the intact globular structure of the protein is necessary for the
physical property.
[0021] The whey protein is used in an amount effective to inhibit
the deposition of organic contaminant such as pitch and
stickies.
[0022] For purposes of the present invention, the term "an
effective deposition inhibiting amount" is defined as that amount
which is sufficient to inhibit deposition in pulp and papermaking
systems. Generally, the whey protein is used in an amount of at
least from about 0.1 ppm, preferable at least from about 0.5 ppm
and more preferable at least from about 1 ppm bases on the parts of
dry pulp in the system.
[0023] The whey protein can be used in the presence of electrolytes
with little or no negative impact as to the effectiveness of the
whey protein for inhibiting the deposition of organic contaminant,
such as pitch and stickies from pulp and paper making systems.
[0024] The whey protein can be used in both basic and acidic
environments. The pH can be as high as about 14 or as low as 1.
[0025] The whey protein can be used in a temperature range of from
at least about 15 C., more preferable 20 C., even more preferable
about 25 C. to a temperature of about 70 C. and more preferable 60
C. and even more preferably from about 55 C. The molecular weight
of the whey protein used in the invention is from about 5,000 to
about 30,000, preferably from about 10,000 to about 25,000 and more
preferable from about 17,000 to about 21,000. The whey proteins
used in the invention are commercially available and available from
Calpro Ingredients.
[0026] The whey proteins of the present invention are effective at
inhibiting the deposition of organic contaminants in papermaking
systems. This may include but not limited to Kraft, acid sulfite,
mechanical pulp and recycled fiber systems. For example, deposition
in the brown stock washer, screen room and decker system in Kraft
papermaking processes can be inhibited. The term "papermaking
systems" is meant to include all pulp processes. Generally, it is
thought that whey proteins can be utilized to inhibit deposition on
all surfaces of the papermaking system from the pulp mill to the
reel of the paper or pulp machine having a pH from at least about 1
and can range to as high as 14 under a variety of system
conditions. More specifically, the whey proteins effectively
decrease the deposition not only on metal surfaces but also on
plastic and synthetic surfaces such as machine wires, felts, foils,
Uhle boxes, rolls and headbox components.
[0027] The whey proteins of the present invention may be compatible
with other pulp and papermaking additives. These can include
starches, titanium dioxide, defoamers, wet strength resins, and
sizing aids.
[0028] The whey proteins of the present invention can be added to
the papermaking system at any stage. They may be added directly to
the pulp furnish or indirectly to the furnish through the headbox.
The whey proteins may also be applied to surfaces that can suffer
from deposition, such as the wire, press felts, press rolls and
other deposition-prone surfaces. Application onto the surfaces can
be by means of spraying or by any other means that coats the
surfaces.
[0029] The whey proteins of the present invention can be added to
the papermaking system neat, as a powder, slurry or in solution,
the preferred primary solvent being water but is not limited to
such. Examples of other carrier solvents include, but are not
limited to, water soluble solvents such as ethylene glycol and
propylene glycol. When added by spraying techniques, the inventive
composition is preferably diluted with water or other solvent to a
satisfactory inhibitor concentration. The whey proteins may be
added specifically and only to a furnish identified as contaminated
or may be added to blended pulps. The whey proteins may be added to
the stock at any point prior to the manifestation of the deposition
problem and at more than one site when more than one deposition
site occurs. Combinations of the above additive methods may also be
employed by feeding either the whey proteins, by way of feeding the
pulp millstock, feeding to the paper machine furnish, and/or
spraying on the wire and the felt simultaneously.
[0030] The effective amount of the whey proteins to be added to the
papermaking system depends on a number of variables including but
not limited to the temperature of the water, additional additives,
and the organic contaminant type and content of the pulp.
Generally, from at least about 0.1 parts, preferably at least about
0.5 parts, more preferably about 1 parts, and more preferably about
1.5 parts of the whey proteins per million parts of pulp in the
system is added.
[0031] Further, the whey proteins have proven effective against
both the pitch and stickies manifestation of organic deposition
problems providing for an effective reduction of these problems in
paper mills utilizing a variety of virgin and recycled fiber
sources.
[0032] In paper machine systems that are closed loop or have water
recycle systems it is advantageous to remove pitch and stickies to
prevent accumulation in the water system. Screening is one method
of removing pitch and stickies. In a preferred method, the pitch
and stickies do not accumulate in the recycled water but are
removed by combining them with the forming paper. In this preferred
method the pitch and stickies are incorporated into the forming
paper in a size and condition (detackified) that the forming paper
quality is not detrimentally affected. It has surprising been found
that by adding protein and cationic polymers to the paper making
system, pitch and stickies are removed from the water system by
combining with the forming paper. Such polymers are sometimes used
for the retention of fines and filler material but may also be used
to retain pitch and stickies.
[0033] In one aspect of the invention, cationic polymers may be
used in combination with proteins. Proteins that by themselves have
some effectiveness to reduce deposition of pitch and stickies can
advantageously be used together with cationic polymers to further
reduce the deposition of pitch and stickies.
[0034] Proteins useful in this aspect of the invention, that can be
combined with the cationic polymers, include but are not limited
to, whey protein, soy protein, ovalbumin, serum albumin,
lactoglobulin, casein, gelatin, wheat protein, and collagen;
preferably the protein is whey protein.
[0035] Cationic polymers useful in the invention include but are
not limited to cationic starch, cationic polyacrylamide, alum,
cellulose derivatives, polyamine such as condensation polymers
produced from aliphatic amines and epichlorohydrin, polyamide amine
condensate, polyamide-amine-epichlorohydrin resins, polyethylene
imine, polyethylene oxide, polydiallyl-dimethyl-ammonium
chloride(poly DADMAC), and melamine-formaldehyde resin. The
polyacrylamides useful in the present invention include
co-polymers, terpolymers and other combinations providing
cationicity to a polyacrylamide polymer backbone.
[0036] Although the above cationic polymers may be pre-mixed with
the proteins, the former may also be added to the aqueous system
separate from the proteins, either before or after the proteins.
The polymers and/or the proteins may be added together or
separately directly to the pulp furnish or indirectly to the
furnish through the headbox. It is particularly advantageous to add
the protein first, mix until the protein has been evenly
distributed in the furnish and then add the cationic polymer before
sheet formation.
[0037] The polymers and/or the proteins may also be applied
together or separately to surfaces that can suffer from deposition,
such as the wire, press felts, press rolls and other
deposition-prone surfaces. Application onto the surfaces can be by
means of spraying or by any other means that coats the
surfaces.
[0038] The blends of protein and cationic polymers are used at
weight ratios of protein to cationic polymer of from about 1:1 to
about 1:100, preferably from about 1:1 to about 1:50, and more
preferably from about 1:1 to about 1:20, are often more effective
than the individual components.
[0039] It has been found that the cationic polymer, poly DADMAC,
may improve the pitch/stickies inhibition effect of the protein's
ability to reduce the tendency for deposition of pitch and
stickies. For example, blends of a whey protein of the present
invention and poly DADAMAC at weight ratios protein to cationic
polymer of from about 1:1 to about 1:100, preferably from about 1:1
to about 1:50, and more preferably from about 1:1 to about 1:20,
are sometimes more effective than the individual components.
[0040] The effective amount of protein plus cationic polymer to be
added to the papermaking system depends on a number of variables
including but not limited to the temperature of the water,
additional additives, and the organic contaminant type and content
of the pulp. Generally, from at least about 0.1 parts, preferably
at least about 0.5 parts, more preferably about 1 parts, and more
preferably about 1.5 parts of the protein plus cationic polymer per
million parts of pulp in the system is added.
[0041] There are several advantages associated with the present
invention compared to prior processes. These advantages include an
ability to function without being greatly affected by the hardness
content of the water in the system or the pH; an ability to
function at low dosages; an ability to function while not adversely
affecting sizing and fines retention, reduced environmental impact;
generally recognized as safe material (GRAS); an ability to allow
the user to use a greater amount of recycled fiber in the furnish;
and improved biodegradability.
[0042] The data below were developed to demonstrate the unexpected
results obtained by the use of the present invention.
EXAMPLES
[0043] Standard Tape Detackification Test (STDT)
[0044] In order to establish the efficacy of the inventive
compositions as deposition control agents on plastic surfaces and
specifically for adhesive contaminants of the sort found in
recycled pulp, a laboratory test was developed utilizing
adhesive-backed tapes as stickie coupons. The stickie coupon can be
fabricated from any type of adhesive tape that will not
disintegrate in water. For this study, tapes made from
styrenebutadiene rubber and vinylic esters were used. Both of these
potential organic contaminants are known to cause stickie problems
in secondary fiber utilization. A second coupon was fabricated from
polyester film such as MYLAR, a product marketed by E.I. Du Pont de
Nemours Chemical Company. This material was chosen because paper
machine forming fabrics are frequently made polyester which is
susceptible to considerable deposition problems caused by stickies
and/or pitch.
[0045] The test involved immersing a 2".times.4" adhesive tape and
a 2".times.4" polyester Mylar coupon into a 600 gram solution being
tested. The pH of all the solutions was about 6, unless otherwise
noted. The solution contained in a 600 mL beaker was placed in a
water bath with agitation and heated to the desired temperature.
After 30 minutes of immersion, the tape and coupon were removed
from the solution and pressed to 10,000 lb force for one minute. An
Instron tensile test instrument was then used to measure the force
required to pull the two apart. The reduction in the force required
indicated that the "stickie" was detackified. The % control or
detackification was calculated by the following equation:
% detackification=100.times.[(untreated force-treated
force)]/untreated force
[0046] The results of this testing are presented in Table III.
4TABLE III Standard Tape Detackification Test Dosage % (ppm), as
Temp. Electrolyte Detack- Treatment actives (.degree. C.)
concentration ification Whey protein 0.25 50 0 4.7 hydrolysate
(7.9% 0.5 50 0 2.7 hydrolysis; average MW = 1,400) Whey protein
0.25 50 0 6.8 hydrolysate (10% 0.5 50 0 22.5 hydrolysis; avg MW =
1,100) Lactalbumin 1 50 0 5.9 Soy protein 1 50 0 31.5 hydrolysate
Sodium caseinate 0.5 50 0 23.8 1 50 0 68.5 Ammonium caseinate 0.5
50 0 54.0 1 50 0 77.8 Calcium caseinate 0.5 50 0 58.9 1 50 0 76.1
Whey protein ( MW = 0.25 50 0 96.5 from about 10,000 0.25 50 0 (pH
11) 95.2 to about 25,000) 0.5 50 0 98.7 0.25 50 15 ppm calcium 96.9
0.25 50 100 ppm calcium 98.5 0.25 50 50 ppm sodium 94.5 0.25 50 200
ppm sodium 97.1 0.15 50 200 ppm sodium 95.5 0.10 50 200 ppm sodium
79.7 1 30 0 90.5 0.5 30 0 87.3 0.25 50 250 ppm calcium 98.2 and 500
ppm sodium (pH = 4) 0.25 50 250 ppm calcium 92.6 and 500 ppm sodium
Polyvinyl alcohol 0.25 50 250 ppm calcium 92.6 (87% hydrolyzed; and
MW = 110,000) 500 ppm sodium 0.5 50 0 76.2 1 50 0 93.4 1 30 0 51 2
30 0 67 5 30 0 92
[0047] As demonstrated in Table III, whey protein proved much more
effective than the whey protein hydrolysates, soy protein,
lactalbumin, sodium caseinate, calcium caseinate, and ammonium
caseinate. As mentioned previously, casein and whey are the two
proteins present in milk; however, they are chemically different.
Without being bound by theory, the superior performance of the whey
proteins as compared to the casein proteins may also be attributed
to the balance of hydrophilic and hydrophobic residues present in
the whey proteins, as opposed to the strongly hydrophilic surface
of the casein proteins. The high molecular weight whey protein also
appeared much more efficacious than the low molecular ones. It also
can be seen that the presence of electrolytes (i.e., sodium and
calcium ions) had no substantial negative impact on the performance
of the whey protein. Furthermore, the high molecular weight protein
still remained very effective at low temperatures (i.e., 30.degree.
C.) and under high pH conditions (i.e., pH 11).
[0048] Filtrate Turbidity Test
[0049] A filtrate turbidity and an observation of pitch deposition
on a Teflon.RTM. stirring bar was used to evaluate protein and/or
cationic polymer activity to prevent deposition as well as retain
pitch particles onto fibers as shown by a decrease of pitch
deposition on a Teflon bar and a decrease of the filtrate
turbidity, respectively. Teflon.RTM. is manufactured by the E.I. Du
Pont de Nemours Chemical Company.
5 Procedure: Conditions Reagents pH = 5.5-6.0 CaCl2.2H20 200 ppm
Ca.sup.+2 Sylvatol 40 350 ppm pitch Abietic Acid 0.5% Consistency
HWD bleached Kraft Fiber 50C 50% NaOH Dilute HCl Calpro 75 BAP 5021
Polyplus 1279 DADMAC
[0050] A. Preparation of Pitch Emulsion--0.5% Pitch Emulsion
[0051] 1. 1800 ml DI water was heated to near boiling (with stir
and covered w/aluminum foil)
[0052] 2. Added 1.5 ml of 50% NaOH to bring pH to approx. 12
(.about.30 drops of 50% NaOH)
[0053] 3. Dissolved 4.0 g of abietic acid
[0054] 4. Dissolved 5.0 g of Sylvatol 40
[0055] 5. Adjusted pH slowly to 8.0 with dilute HCl. The suspension
became cloudy and milky.
[0056] B. Preparation of Fiber--1% Consistency
[0057] 1. Weighed 20 g dry lap bleached hardwood pulp tore into
approx. 1".times.1" pieces
[0058] 2. Soaked in 2000 ml DI water for 15 min or more
[0059] 3. Transferred soaked pulp to TAPPI Disintegrator
container
[0060] C. Operation of Britt Jar Test
[0061] 1. Filled a 600 ml beaker with 250 g of a 1% consistency
pulp slurry and 250 g of boiling DI water. Maintained the temp.
near 50 C. by heating the beaker
[0062] 2. Added Calcium solution (4 ml of 9.2% CaCl2.2H2O)
[0063] 3. Added pitch suspension (35 g)
[0064] 4. Added 5-20 ppm protein or cationic polymer (i.e., 10ppm=5
g of 0.1% soln)
[0065] 5. Adjusted pH with dilute HCl to 5.5-6.0(checked pH probe
in buffer to ensure that there was not a build up of pitch)
[0066] 6. Stirred for 30 min
[0067] 7. Added 5-20 ppm cationic polymer or protein
[0068] 8. Stirred for 15 min
[0069] 9. Transferred "7" to a Britt Jar equipped with a 22 micron
screen and stirred 800 RPM for 30 sec, filter, then the filtrate
was collected for turbidity measurements
[0070] The results of this testing are presented in Table IV:
6TABLE IV Turbidity and Pitch Deposition Test Treatment Turbidity
Teflon deposition Untreated 426 Slight amount of pitch deposition 1
ppm poly DADMAC 365 Same as untreated 2 ppm poly DADAMAC 258 Same
as untreated 5 ppm poly DADMAC 198 Same as untreated 10 ppm poly
DADMAC 249 Moderate amount of pitch deposition 30 ppm poly DAD MAC
62 Lots of deposition 10 ppm whey protein 395 No pitch 20 ppm whey
protein 370 No pitch 1 ppm whey protein .about./30 42 Same as
untreated ppm poly DADMAC 5 ppm whey protein .about./30 21 No pitch
ppm poly DADMAC 20 ppm whey protein /30 19 No pitch ppm poly DADMAC
20 ppm PVA 403 No pitch 1 ppm PVA/30 ppm poly 70 Same as untreated
DADMAC 5 ppm PVA/30 ppm poly 96 Same as untreated DADMAC 10 ppm
PVA/30 ppm 88 Same as untreated poly DADMAC 20 ppm PVA/30 ppm 103
No pitch poly DADMAC 5 ppm whey protein 24 No pitch adjusted to pH
12 then blended with 15 ppm poly DADMAC prior to adding to the pulp
slurry
[0071] The whey protein used in the turbidity test had a molecular
weight of from about 10,000 to about 25,000. Table IV shows that
whey protein prevents pitch deposition on a Teflon bar as well as
lowers the filtrate turbidity (an indication of pitch retention)
when used in combination with a cationic polymer.
[0072] While this invention has been described with respect to
particular embodiments thereof, it is apparent that numerous other
forms and modifications of this invention will be obvious to those
skilled in the art. The appended claims and this invention
generally should be construed to cover all such obvious forms and
modifications which are within the true spirit and scope of the
present invention.
* * * * *