AU663170B2 - Methods for controlling the deposition of organic contaminants in pulp and papermaking processes - Google Patents

Description

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AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): BETZ INTERNATIONAL, INC.

A.R.B.N. 001 775 551 Invention Title: METHODS FOR CONTROLLING THE DEPOSITION OF ORGANIC CONTAMINANTS IN PULP AND PAPERMAKING PROCESSES tees 54 5* S S 4 OS 5554 S S S S* S ~04 0409 Sq..

6 4 4e*& The following statement~ is a full description of this invention, including the best method of performing it known to me/us: 7 r D-758 METHODS FOR CONTROLLING THE DEPOSITION OF ORGANIC CONTAMINANTS IN PULP AND PAPERMAKING PROCESSES FIELD OF THE INVENTION The present invention relates to methods for inhibiting the deposition of organic contaminants from pulp in pulp and papermaking systems.

BACKGROUND OF THE INVENTION The deposition of organic contaminants in the pulp and paper industry can cause both quality and efficiency problems in pulp and 10 papermaking systems. Some components occur naturally in wood and are released during various pulping and papermaking processes. 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.

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i i Y I -2- Stickies is a term that has become increasingly used to describe deposits that occur in systems using recycled fiber. These deposits often contain the same material found in "pitch" deposits in addition to adhesives, hot melts, waxes, and inks. All of the aforementioned materials have many common characteristics including: hydrophobicity, deformability, tackiness, low surface energy, and the potential to cause problems with deposition, quality, and efficiency in the process. Diagram 1 shows the complex relationship between pitch and stickies discussed here.

Diagram 1 Pitch Stickies *4 r 0 00 Natural Resins (fatty and resin acids, fatty esters, insoluble salts, sterols, etc.) Defoamers (oil, EBS, silicate, silicone oils, ethoxylated compounds, etc.) Sizing Agents (Rosin size, ASA, AKD, hydrolysis products insoluble salts, etc.) Coating Binders (PVAC, SBR) Waxes Inks *040 .00.

0* O*r Hot Melts (EVA, PVAC, etc.) Contact Adhesives (SBR, vinyl acrylates, polyisoprene, etc.) -3- The deposition of organic contaminants 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.

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 15 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.

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A2 4.- -4- 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 cause 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.

Methods of preventing the build up of deposits on the pulp and papermill equipmnent 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 15 become incorporated in the sheet. Preventing deposition is thus greatly preferred where it can be effectively practiced.

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 20 fiber. Often very different treatment chemicals and strategies were used to control these separate problems.

*00* Current trends are for increased mandatory use of 1recycled fiber in all systems. This is resulting in a co-occurance of 0 to stickies and pitch problems in a given mill. It is desirable to 25 find treatment chemicals and strategies which will be highly 4 1 i i I FI effective at eliminating both of these problems without having to feed two or more separate chemicals. The materials of this invention have clearly shown their ability to achieve this goal.

Pitch control agents of commerce have historically included surfactants, which when added to the system, can stabilize the dispersion of the pitch in the furnish and white water. Stabilization can help prevent the pitch from precipitating out on wires and felts.

Mineral additives such as talc have also found use and can reduce the tacky nature of pitch by adsorbing finely dispersed pitch particles on their surfaces. This will reduce the degree to which the particles coagulate or agglomerate.

Polyphosphates have been used to try to maintain the pitch in a finely dispersed state. Alum has also been widely used to 15 reduce deposition of pitch and related problems.

Both chemical and non-chemical approaches to stickies control are employed by papermakers, Non-chemical approaches include furnish selection, screening and cleaning, and thermal/mechanical dispersion units.

,rr 20 Chemical treatment techniques for stickies control include dispersion, detackification, wire passivation and cationic fixation. Chemicals used included talc, polymers, dispersants and surfactants.

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6 SUMMARY OF THE INVENTION The present invention pertains to methods for inhibiting the deposition of organic contaminants from pulp in pulp and papermaking systems comprising treating said systems with an effective amount of a hydrophobically substituted acrylamide polymer.

The present invention also provides a method for inhibiting the deposition of organic contaminants from pulp in pulp and papermaking systems comprising treating said systems with an effective amount of a hydrophobically substituted polyethylene oxide polymer.

9* 46 tor too* 6 15 ad 0 t 20 Of 9 to 0 6 0 a 0O 9 0 Common organic contaminants include constituents which occur in the pulp (virgin, recycled or combinations) having the potential to deposit and reduce paper machine performance or paper quality. This will include natural resins such as fatty acids, resin acids, their insoluble salts, fatty esters, sterols and other organic constituents, like ethylene bis-stearamide, waxes, sizing agents, adhesives, hot melts, inks, defoamers, and latexes that may be found to deposit in papermaking systems.

DESCRIPTION OF THE RELATED ART Surfactants, anionic polymers and copolymers or anionic monomers and hydrophobic monomers have been used extensively to prevent pitch deposition of metal soap and other resinous pitch components. See "Pulp and Paper", by James P. Casey, Vol. II, 2nd Edition, pp. 1096-7.

United States Patent No. 4,871,424, Dreisbach et al., October 1989 teaches the use of polyvinyl alcohol and copolymers of vinyl alcohol to inhibit pitch deposition from pulp in papermaking systems.

SstatiunilWkoopJ367433 93 oc 1 8 United States Patent No. 3,081,219, Drennan et al., March 1963 teaches the use of a polymeric N-vinyl lactam to control pitch in the making of paper for sulfite pulps.

United States Patent No. 3,154,466, Nothum, October 1964, teaches the use of xylene sulfonic acid-formaldehyde condensates and salts thereof as pitch dispersants in papermaking.

United States Patent No. 3,992,249, Farley, November 1976 discloses the use of certain anionic vinyl polymers carrying hydrophobic-oleophilic and anionic hydrophilic substituents when added prior to the beating operation in the range of about 0.5 parts to 100 parts by weight of the fibrous suspension to inhibit the deposition of adhesive pitch particles on the surfaces of pulp-mill equipment.

United States Patent No. 4,846,933, Dreisbach et al., July 1989 teaches the use of a water soluble polymer containing p polymerized units of methyl vinyl ether having methyl ether groups to control pitch deposition from pulp.

United States Patent No. 4,822, 452, Tse et al., April 1989 teaches the use of urethane block copolymers, as nonionic 20 associative thickeners. These copolymers act as thickeners in the preparation of a fibrous web of textile length fibers.

4 1thka I 2 soitv hcees hs ooyesata hceesi h t 4 -8- "The Influences of washing, defoamers and dispersants on pitch deposition from unbleached Kraft pulps," N. Dunlop-Jones and L.H. Allen, Journal of Pulp and Paper Science: Vol. 15 No. 6, November 1989 teaches the use of nonylphenol ethoxylate compounds to inhibit pitch deposition in papermaking systems.

U.S. Patent No. 4,781,794, Moreland, November 1988 teaches methods for detackifying adhesive materials contained in secondary fiber. The methods comprise adding an unsubstituted methyl ether cellulose derivative to the secondary fiber. Methyl cellulose is a representative compound.

U.S. Patent No. 4,886,575, Moreland, December 1989 teaches the use of polyvinyl alcohol to inhibit the deposition and adherence of stickies to the repulping equipment.

eit U.S. Patent No. 4,886,575, Moreland, December 1989 teaches 15 the use of polyvinyl alcohol to inhibit the deposition and adherence of stickies to the repulping equipment.

U.S. Patent No. 4,923,566, Shawki et al., May 1990 teaches methods for pacifying stickies by applying urea between the drying rolls and the finished produce reel.

20 U.S. Patent No. 4,643.800, Maloney et al., February 1987 teaches removing and dispersing contaminant from secondary fiber during repulping. Nonionic surfactants and dispersants are used to separate the contaminant from the fiber.

i -9- DETAILED DESCRIPTION OF THE INVENTION The present inventors have discovered that the deposition of organic contaminants from pulp in pulp and papermaking systems can be inhibited by treating said pulp and papermaking systems with an effective amount of a hydrophobically modified associative polymer.

These associative polymers act to inhibit the deposition when adsorbed onto contaminants or contaminant prone surfaces.

This may be achieved by continuous or batch addition to the stock (virgin, recycled and/or combination) prior to the site of concern or by continuous application directly to the site of primary contamination the wire) prior to the accumulation of the deposit. The term hydrophobically associative polymer relates to polymers which have two or more hydrophobic regions giving them the 15 capacity to form associative networks by the attraction/interaction of the hydrophobic regions.

Hydrophobically associating water-soluble polymers possess unusual rheological characteristics which are thought to arise from the intermolecular association of neighboring hydrophobic substituents. The hydrophobic substituents are incorporated onto the polymer through chemical grafting or a suitable co-polymerization procedure. The hydrophobic groups are incorporated to a level so as to not render the final modified polymer water insoluble. These S polymers have found use in industrial fields such as enhanced oil recovery and in the formulation of latex based paints. See Carbohydrate Polymers 12 (1990) 443-459, R. Tanaka et al., the contents of which are wholly incorporated herein.

These polymers are widely used as rheology modifiers where their unique associative capabilities are very important. In this application they are often referred to as "associative thickeners".

They are very different in behavior from typical high molecular weight water-soluble polymers. They also behave very differently from dispersants which are low molecular weight and highly charged.

Associative thickeners are water-soluble polymers containing hydrophobic groups which are capable of non-special hydrophobic association, similar to surfactants. See Polymers as Rheology Modifiers, Chapter 12. page 207, Systems Approach to Rheology Control, P.R. Howard, E.L. Leafure, S.T.

4 15 Rosier and E.J. Schaller, 'I One group of these hydrophobically modified associative polymers are the hydrophobically modified hydroxyethyl cellulose associative polymers. These polymers are available from Aqualon Company as Natrosol Plus 330 and Plus 430 and previously from Hercules as WSP-D-330. The hydrophobically modified hydroxyethyl cellulose associative polymers are described by K.G. Shaw and D.P.

.Liepold, Journal of Coatings Technology 57, No. 727, pp.

63-72(August, 1985), incorporated herein by reference.

t -11- Another family of hydrophobically modified associative r' ymers are the hydrophobically modified associative water-soluble anionic polymers which are derived from ethylenically unsaturated acids such as acrylic acid and methyacrylic acid; ethylenically unsaturated monomers such as 2-acrylamido-2-propane suifonic acid(AMPS1 and 1-allyloxy-2-hydroxypropyl sulfonate and unsaturated acid monomers in general. Acrylate-based monomers are the preferred monomers in deriving these polymers. Representatives of these -polymers are available from Rohm Haas as Acrysol®TT615, Acrys,)t ICS 1; Polyphobe 107 available from Union Carbide and the Alcogum SL70 and 296W polymers available from Alco Chemical Corporation. Polymers based on maleic acid copolymers and naphthalene sulfonate condensates have not been effective in this invention. It is thought that this is due to their inability to achieve high enough molecular weight to be effective.

Alcogum SL70 is thought to be a terpolymer of methacrylic acid, ethyl acrylate, and a nonionic monomeric surfactant. The nonionic surfactant monomer consisted of a poly(oxyethylene) compound and an alkyl hydrocarbon segment. The components are 20 consistent with the patent literature in an approximate ratio of 40:50:10. The Alcogum 296W polymer is the sodium salt of poly(acrylic acid) prepared by the hydrolysis of poly(methyl t acrylate) and was found to contain approximately 16 mole percent residual methyl acrylate units.

-12- In another embodiment, the modified associative polymers are hydrophobically substituted acrylamide copolymers. These copolymers result from substitution of an acrylamide monomer to some extent to result in a copolymer. These copolymers can possess the comonomers other than acrylamide with the following structures: CH3 C C 0 -(CH 2

CH

2 0)24 C 22

H

4

CH

3 C C

CH

3 C C 0 -(CH 2

CH

2 0)10 (CH 2 8

CH

3 [0 C 4 ,5 C C] -OH

CH

3

CH

3

(II)

(III)

ei o *4 4o 4 4 4444 roo 4.44 4* 4 4 9 4 4 4.4.

4.* 4 .4.4 4 4 44 .4.4 a eooe eee e

CH

3 0 C C C [CH 2

CH

2 0] (CH 2 8

CH

3

(IV)

Other representative modified polymers of this invention are hydrophobically substituted polyethylene oxide polymers. These multihydrophobically substituted polymers indicate that two or more hydrophobic groups are desirable for optimum efficiency. These polymers can have hydrophobic groups which are combined to the polyethylene oxide polymer by ester linkages. Preferred polyethylene oxide polymers include polyethylene oxide dioleate esters.

Mapag()6000 available from PPG/Mazer is a representative polyethylene oxide polymer.

I; ~liWltQII II~-~IC-*IUIB*- i L_*I*C~ S Ii -13- Other hydrophobically associative thickener polymers based on modified ethylene oxide are also effective deposition control polymers as defined by this invention. PluracolR TH922 and TH916 available from BASF are useful polymers in accordance with this invention.

A further embodiment of this invention utilizes associative water-soluble urethane polymers. These polymers have alternating blocks of hydrophobic groups and hydrophilic groups. These polyethylene glycol/ethylene oxide based urethane block polymers may have molecular weights in the range of (10,000 to 2,000,000) and are disclosed in U.S. Patent Nos. 4,079,028 and 4,155,892 as paint thickeners. These references are wholly incorporated by reference herein. Commercial formulations of these copolymers are available as Acrysol R RM-825 and Acrysol R RM-1020 from 15 Rohm and Haas. These polymers comprise urethane block copolymers in different carrier fluids. For instance, AcrysolR RM-825 is a 25 percent solids grade of polymer in a mixture of 25 percent butyl carbitol(a diethylene glycol monobutyl ether) and 75 percent water. Similar copolymers are available from Union Carbide Corporation as UCARR SCT 200 and UCARR SCT 275. These compounds are discussed in U.S. Patent 4,496,708. Similar compounds are also available from Henkel Corporation under the trade names DSX 1514 and DSX 1550. These compounds are discussed in U.S. Patent 4,438,225.

25 The polymers of the instant invention are effective at controlling the deposition of organic contaminants in papermaking systems. This may include Kraft, acid sulfite, mechanical pulp and recycled fiber systems. For example, deposition in the brown -14stock washer, screen room and decker system in Kraft papermaking processes can be controlled. The term "papermaking system" is meant to include all pulp processes. Generally, it is thought that these polymers can be utilized to prevent deposition on all surfaces from the beginning of the pulp mill to the reel of the papermachine under a variety of pH's and conditions. More specifically, these polymers effectively decrease the depositio not only on metal surfaces but also on plastic and synthetic surfaces such as machine wires, felt, foils, Uhle boxes and headbox components.

The polymers may be added to the papermaking system along with other papermaking additives. These can include other polymers, starch and sizing aids.

The polymers of the present invention can be added to the 15 pulp at any stage of the papermaking system. They may be added directly to the pulp furnish or sprayed on wires, felts, press rolls or other deposition-prone surfaces. They may 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 20 such. They may be added specifically and only to a furnish Sidentified as contaminated or may be added to blended pulps. The polymers 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 way of feeding the pulp millstock, feeding to the papermachine furnish, and spraying 9 on the wire and felt simultaneously. The effective amount of these polymers to be added to the papermaking system depends on a number of variables, including the pH of the system, hardness of the water, temperature of the water, additional additives, and the organic contaminant type and content of the pulp. Generally, parts per million to about 150 parts per million is added to the paper making system. Preferably, from about 10 parts per million to about 50 parts per million is added to the system.

There are several advantages anticipated with the present invention as compared to prior processes. These advantages include: an ability to function without being greatly affected by hardness of the water in the system; an ability to function with lower foaming than surfactants, an ability to function while not 0# S adversely affecting sizing, fines retention, and an ability to function at very low dosages, Peduced environmental impact, and improved biodegradability. Also, the ability of these agents to function in spite of dilution has been clearly shown.

S"Further these agents have proven effective against both the pitch and stickies manifestation of organic deposition problems providing for an effective reduction of these problems in e mills employing a variety of virgin and recycled fiber sources.

~The data set forth below were developed to demonstrate

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*~4 u the unexpected results occasioned by use of the invention.

a 4 601C 9 9 -16- The following examples are included as being illustrations of the invention and should not be construed as limiting the scope thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS It was found that pitch (natural resins, etc.) could be .made to deposit from a 0.5% consistency fiber slurry contairJng approximately 2000 parts per million of a laboratory pitch preparation by placing the slurry into a metal pan suspended in a laboratory ultrasonic cleaner water bath. The slurry contained 10 0.5% bleached hardwood Kraft fiber, approximately 2000 parts per million of the potassium salt of a fatty acid blend, approximately 200 parts per million calcium from calcium chloride and approximately 300 parts per million sodium carbonate. The slurry was

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maintained at 50 0 C and at a pH of 11.

15 It was stirred gently by an overhead stirrer and subjected S* t to ultrasonic energy for 10 minutes. The deposit weight was determined by subtracting the starting weight of the pan from the t weight of the pan plus the deposit after completion of the test.

This was converted to percent control of deposit using the formula:

*SSS

control of deposit untreated weight treated weight X 100 untreated weight i I V 4 i t -17- A high percent control of deposit is indicative of good deposit inhibiting qualities. Studies of this type were conducted using hydrophobically modified associative polymers of the type described in this invention. Results of this testing is reported in Table I.

TABLE I Control 50 ppm 10 ppm Treatment Agent Unmodified Hydroxyethyl Cellulosel tr

S

SI

t, Ir r 10 Hydrophobically modified Hydroxyethyl cellulose 2 Hydrophobically modified Hydroxyethyl cellulose 3 Hydrophobically modified Hydroxyethyl cellulose 4 *t *ttc *i

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1 available 2 available 3 available 4 available commercially commercially commercially commercially Natrosol H4BR NatrosolPlus 330 Natrosoflus 430 Hercules WSP-D-330 These results indicate that the associative polymers are more efficient unmodified polymers of a, related type.

hydrophobically modified deposit inhibitors than the These results further indicate that the polymers of this invention are effective at controlling deposition on metal surfaces and under alkaline conditions and specifically referred to typically as "pitch".

Il [i I -18- Further studies of the testing described in Table I were conducted using hydrophobically modified associative anionic polymers and anionic dispersants disclosed as being preferred in the prior art. These results appear in Table II.

TABLE II

C

IC

CI 4 41

'CI

44,4 4i Treatment Agent Hydrolysed Styrene Maleic Anhydride Copolymer 1 Hydrolysed Diisobutylene Maleic Anhydride Copolymer 2 Hydrophobically Associative Anionic Polymer 3 Hydrophobically Associative 15 Anionic Polymer 4 Hydrophobically Associative Anionic Polymer Hydrophobically Associative Anionic Polymer 6 Hydrophobically Associative Anionic Polymer 7 82 12 13 13 Control 100 ppm 50 opm 98 93 -19- 1 Available commercially 3,992,249, Farley 2 Available commercially Farley 3 Available commercially i 4 Available commercially 5 Available commercially 6 Available commercially 7 Available commercially as Alco SMA 1000, see also U.S.

as Tamol 731, see also U.S. 3,992,249, Alcogum Alcogum 296W.

AcrysorTT615 Acryso rCS 1 Polyphobe 107 9.

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a *~9 4 a *liS These results illustrate that the polymers of this invention are surprisingly more effective for deposition control 10 than known deposition inhibitors specifically, they show efficacy at controlling pitch deposition.

Further testing as described in Table I was conducted using hydrophobically substituted acrylamide copolymers. The hydrophobic comonomers possess the structures: t

CH

3 cC-C CH3 C H 3

CH

3 0 -(CH 2

CH

2 0)24 C 22

H

4 0-(CH 2

-CH

2 -0) 10 0- (CH 2 8

-CH

3 (0 C C] 4 [-c OH

CH

3

(IV)

a S 'a a is 4* a S aS S.

a a .45.

5 a

[CH

2

CH

2 016 -0(CH 2 8

CH

3 The results of their testing appear in Table III.

S as a S a. as 4 5**5 -21- Treatment Mole Agent -Hydrophobe 1 0.0 1 0.3 1 0.6 1 1.0 1 2.0 1 2.0 1 2.0 I 3.0 I 4.0 TABLE III Molar Ratio

AMD/IPA

34:1 No1IP 11:1 17:1 11:1 11:1 1711 11:1 No IPA No IPA No IPA 50 0Dm 20 31 48 54 72 68 66 66 Control 0 39 41 24 49 49 45 16 10 pnm 0 23 32 16 It 94 II

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'p Itt 9. 49 94 St #1 9 4 t t 9. 4 *9St *4t9 9* 9 9*91 15 II 1I 20 II

II

r Ai -22- TABLE III (cont'd) Treatment Mole Agent HvdroDhobe Molar Ratio

AMD/IPA

Control 50 ppm 20 ppm 10 ppm

IV

IV

IV

IV

IV

IV

IV

IV

IV

11:1 11:1 11:1 11:1 No IPA No IPA No IPA No IPA No IPA C. C

CC..

C.r

*C

*i 4 *i S

C

SC S

C

S.C

CCC.

*r C The results of Table III indicate that the hydrophobically modified associative polymers of the present 15 invention are effective at inhibiting deposition. The results illustrate that substituted acrylamides of this invention are more efficient at inhibiting deposition broadly and pitch deposition specifically than unsubstituted acrylamides.

Additional testing was performed as described in Table I using hydrophobically substituted polyethylene oxides. These results are reported in Table IV.

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-23- K TABLE IV Control Treatment Agent 50 ppm 10 ppm Nonyl Phenol Ethoxylate (Surfonicl-95) 81 9 Polyethylene oxide dioleate (Mapeo6000) 85 36 Myristal glycol (Dapral 282) 88 46 The results indicated in Table IV are further indicative that the multi-hydrophobically substituted polyethylene oxides are effective for inhibiting deposition. They were also shown to be more effective than the known mono-hydrophobically substituted deposition inhibitors.

SHydrophobically modified ethylene oxide polymers were also tested according to the procedure described in Table I.

The results of this testing appear in Table V.

TABLE V Control Treatment AQent 50 ppm 10 pp Hydrophobically modified 95 88 Associative Ethylene Oxidel Copolymer Hydrophobically Modified Associative ethylene oxide 2 95 86 k <t tCopolymer 1 Available commercially as Pluracol H922 2 Available Gmmercially as PluracolTH916 -24- The results presented in Table V further show that the polymers of this invention provide highly effective and efficient deposition control and more specifically, pitch control.

Further studies of the testing described in Table I were conducted using commercially available associative water-soluble urethane polymers. These testing results anpear in Table VI.

TABLE VI Percent Control of Pitch 100 ppm 50 Dpm 10 ppm

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*4t a a *4 r at *i t **4 p Treatment Aqent Nonylphenol ethoxylatel Sodium lignosulfata 2 Hydrolyzed styrene maleic anhydride 3 Diisobutene maleic anhydride 4 Water-soluble urethane polymer Water-soluble urethane polymer 6 15 Water-soluble urethane polymer 7 Water-soluble urethane polymer 8 Water-soluble urethane polymer 9 Water-soluble urethane polymer 10 1 20 2 3 4 6 7 8 9 commercial commercial commercial commercial commercial commercial commercial commercial commercial commercial available available available available available available available available available available Lignosol XD Alco SMA 1000 Tamol 71 Acryso RM 1020 Acrysol M 825 DSX 1514 DSX 5 50 UCARSCT 200 UCAR(CT 275 These results indicate that the associative water-soluble urethane polymers of the present invention were more effective for inhibiting deposition than the known deposition inhibitors. These results further indicate that these polymers are effective at controlling deposition on the metal surfaces of papermaking systems.

Further studies of the testing described in Table I were conducted using water-soluble urethane polymers synthesized using a wide variety of reactive isocyanates, water-soluble diols, branching agents, and terminating groups. These polymers consti tute polyethylene oxide/polyethylene glycol polymers with urethane linkages. They are synthesized utilizing isocyanate compounds such as hexamethylene diisocyanate, toluene diisocyanate, isophorone Sdiisocyanate, and other dihydroxyl reactive materials. These 1. polymers are also synthesized utilizing water-soluble diol 15 compounds and can be selected from the group consisting of S.o tpolyethylene glycol compounds with molecular weights from about 400 to about 1450 and ethylene oxide/propylene oxide block copolymers.

SuThe isocyanates included hexamethylene diisocyanate, toluene o. diisocyanate, isophorone diisocyanate and other dihydroxyl reactive materials. The water-soluble diols included PEG olyethylene Glycol) 400, PEG 600, PEG 1000, PEG 1450, Pluronic L-35 and The branching agents included glycerol and pentaerythritol. The terminating groups (monohydroxy compounds) Sincluded 2-ethyl hexanol, nonyl phenol, nonyl phenol ethoxylates 25 with 40 and 70 moles EO, and secondary alcohol ethoxylates with Smoles EO.

to -26- These testing results appear in Table VII.

TABLAE VII Urethane Polymer Components Branching Isocvanate Aaent Percent Control of Deposition 50 Dom DDM Termi nati on Aae nt Di ol if i S I S 55CC

CI

Si iC~ ii s ii 4.

i St., a I

S

S SI. .514 S S S S St..

II

it PEG 400 PEG 400 'PEG 600 Pluronic L-35 PEG 1000 PEG 1000 PEG 1000 Pluronic 10R5 15 PEG 1450 PEG 1450 PEG 1450 PEG 1450 PEG 1450 20 PEG 1450 PEG 1450 PEG 1450 HMD I HMD I TD I TD I HMD I HMD I HMD I HMD I

ISOPH

ISOPH

ISOPH

ISOPH

HMD I

ISOPH

!SOPH

ISOPH

ISOPH

ISOPH

Glycerol Pent a 2- EH 2- EH 2- EH 2- EH 2- EH N PH 2-EH 2- EH NP-70 NP-40 NP- 70 15-S5-30 15-S5-30 15-S5-30 15-S-30 15-S-30 63 91 21 82 0 91 24 89 23 9 23 54 89 88 12 92 21 97 62 96 64 Glycerol Glycerol Glycerol -27- PEG (MW) polyethylene Glycol Pluronic L-35 EO/PO/EO Block Copolymer Pluroni lOR5 PO/EO/PO Block Copolymer HMDI Hexamethylene diisocyanate TDI Toluene Diisocyanate ISOPH Isophorone Diisocyanate PENTA Pentaerythritol 2-EH 2-Ethyl Hexanol N-pH Nonyl Phenol NP-70 Nonyl Phenol with 70 moles EO Nonyl Phenol with 40 moles EO 15-S-30 Secondary Alcohol with 30 moles EO These results indicate that water-soluble urethane polymers of the present invention having a widely varying character with respect to branching, end groups, and character of the backbone (diols and isocyanates used) can be highly effective for controlling pitch deposition.

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SON.

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-28- In order to establish the efficacy of the materials of this invention as deposition control agents, on plastic surfaces and specifically for adhesive contaminants of the sort found in recycled fiber, a laboratory test was devised utilizing adhesive-backed tapes as stickie coupons. The stickie coupon can be fabricated from any type of adhesive tape that will not disintegrate when placed in water. For the study, tapes made from a styrenebutadiene rubber and vinylic esters were used. Both of these potential organic contaminants are known to cause problems 1 'stickies" in secondary fiber utilization. A second coupon was fabricated from polyester film such as the product marketed as MYLAR by the DuPont Chemical Company. This material was chosen because papermachine forming fabrics are frequently made of polyester which is susceptible to considerable problem caused by 15 stickies.

500 mL of solutions in 600 mL beakers containing various deposit control agents are placed in a water bath heated to 0 C. The tape and the polyester film coupons are placed in the 2 test solution so the adhesive side of the coupon faces away 20 from the polyester film coupon. After 1 hour of immersion, the adhesive side of the stickie coupon is placed in contact with the polyester coupon and pressed to 1000 pound force.

.4 The average peel strength of the bond formed between the tape coupon and the polyester coupon was measured with an Instron tensile tester. The peel strength of the bond formed between the stickie tape coupon and the polyester coupon was

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CA -29interpreted as a measure of the tendency for an organic contaminant to attach to components of a paper-machine and cause runnability or product quality problems. More specifically, this indicates the tendency of a stickies deposit to form on a plastic surface.

The results of this testing appear in Table VIII.

TABLE VIII Detackification Treatment Agent Dosaqe (ppm) 0.2 0.5 1.0 2.0 5.0 10.0 25.0 t t C C

ICE

CCC

''V

LC

CCC.

*5S

C(

1. Octylphenoxy Poly- (ethyleneoxy) ethanol 2. Nonylphenolethoxylate 3. Dodecylphenoxy Poly (ethyleneoxy) ethanol 15 4. Block Copolymer of Ethyleneoxide/propylene oxide Sodium Salt of Condensed Naphthalene Sulfonic Acid 6. Water Soluble Urethane Polymer 7. Water Soluble Urethane Polymer 25 8. Water Soluble Urethane Polymer 9. Water Soluble Urethane Polymer 2.8 9.4 18.7 47.3 93.7 4.7 29.1 64.2 86.3 100 31.2 56.0 94.7 100 100 5.0 27.1 60.0 80.4 83,7 0 0 0 0 1.4 67.9 80.9 89.4 100 100 71.1 89.2 100 100 100 69.0 80.9 93.9 100 100 85.3 95.9 100 100 100 Bb :d Izra 1 2 3 4 5 6 7 8 9 commercial commercial commercial commercial commercial commercial commercial commercial commercial available available available available available available available available available Triton® 114 Surfoni Igepal N-520 Pluronic F-108 Tamol Acryso RM 825 Acryso QR-708 DSX 1514 DSX 1550 The results shown in Table VIII further support the efficacy of the present invention (examples 6-9 of Table VIII) for deposit control on plastic surfaces. They showed better efficacy relative to prior art deposit control agents (examples 1-5 of Table VIII). This demonstrates the effectiveness of nonionic polymers of the present invention for stickies deposition control.

Further studies of the testing described in Table VIII were conducted using commercially available water-soluble anionic polymers.

These test results appear in Table IX.

TABLE IX Detackification I! t i.

*I C: ii

C

.5.

Treatment Agent 0.' 1. Hydrolysed diisobutylene maleic anhydride copolymer 2. Hydrophobically associative anionic polymer 63 3. Hydrophohically associative anionic polymer 12 Dosage (ppm) 5 1.0 2.0 5.0 10.0 50.0 100.0 2.7 8.2 0 .1 98.6 98.2 97.8 .7 97.6 98.5 98.7 *r

C

4. Hydrophobically associative anionic polymer Hydrophobically associative anionic polymer 80.0 97.9 98.0 98.9 96.4 97.6 97.4 98.7 -31- 1 commercially available as Tamol 731 2 commercially available as Acrysol TT615 Scommercially available as Acrysol aICS 1 4 commercially available as Alcogum 5commercially available as Alcogum SL-78 These results indicate that water-soluble anionic associative polymers of this invention can be effective for .controlling organic contaminant deposition (examples 2-5 of Table IX). They further indicate the efficacy of these anionic polymers at controlling stickies deposition. These results further illustrate how surprisingly more effective this invention is than prior art anionic dispersant deposition control agents (example 1 Sof table IX).

Papermaking consists of various processes which can be 15 affected by sudden changes in pH, temperature, dilution concentration), shear force, etc. Severe changes in these parameters can cause system shock which adversely impact paper production. Deposit control agents that can strongly adsorb onto the organic contaminant surface and resist the desorbing effects of dilution are highly desirable. Not only will deposition control be improved, but also the required dosage will be reduced, while negative side effects, such as forming and wet-end inter- •.ferences, will be reduced or eliminated. The procedure outlined in Table VIII was modified to examine the effect of dilution on deposition control. Dilution was accomplished by immersing the adhesive tape and MYLAR in distilled water for 30 minutes after the initial immersion. This can be repeated as many t'imes as desired. The results of the testing are tabulated in Table X.

paameerscan aus sytemshoc whch dveselyimpct ape '~ii podutio. Dposi cotro agntstha canstrngl adorbont -32- TABLE X Sample Concen. No 1st 2nd 3rd (ppm) Dilution Dilution Dilution Dilution 1 2 3 4 6 7 8 4th Dilution 0 0 0 89 96 Sample Sample Sample Sample Sample Sample Sample Sample octylphenoxy poly(ethyleneoxy)ethanol nonylphenol ethoxylate dodecylphenoxypoly(ethyleneoxy) ethanol block copolymers of ethylene oxide and propylene oxide water soluble associative polymer available as Acryso RM-825 water soluble associative polymer available as QR-708 water soluble associative polymer available as DSX-1514 water soluble associative polymer available as DSX-1550 c f As shown in Table X, the associative polymers of this invention (samples 5-8 of Table X) in this test were very effective after the fourth dilution. They showed better performance relative to prior art deposit control agents (samples 1-4 of Table This demonstrates a strong adsorbing power and good resistance to the desorbing effects of dilution.

i t l -33- While this invention has been described with respect to particular embodiments 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.

i e *t *904 .4 0 0 40i

I

Claims (45)

1. A method for inhibiting the deposition of organic contaminants from pulp in pulp and papermaking systems comprising treating said pulp and papermaking systems with an effective amount of a hydrophobically substituted acrylamide copolymer.

2. The method as claimed in claim 1 wherein said hydrophobically substituted acrylamide copolymer has the structure: CH 3 0 I 11 C C C 0 -(CH 2 CH 2 0) 24 C 22 H 4

3. The method as claimed in claim 1 wherein said hydrophobically substituted acrylamide copolymer has the structure: fU CH 3 0 S= C C 0 -(CH 2 CH 2 0 )10 0 (CH 2 8 CH3

4. The method as claimed in claim 1 wherein said V hydrophobically substituted acrylamide copolymer has the 15 structure: CH 3 0 S' C C C 4 5 -0 C C OH 3 ^3 CH 3 CH 3 t, 5. The method as claimed in claim 1 wherein said hydrophobically substituted acrylamide copolymer has the structure: CH 3 0 S C [CH CH 2 0] 6 (C 2 8 C 3

6. A method for inhibiting the deposition of organic sltallunitaulepi0743,93 daaim b 27.7 35 contaminants from pulp in pulp and papermaking systems comprising treating said pulp and papermaking systems with an effective amount of a hydrophobically substituted polyethylene oxide polymer.

7. The method as claimed in claim 6 wherein said hydrophobically substituted polyethylene oxide polymer has hydrophobic groups which are combined to said polyethylene oxide polymer by ester linkages.

8. The method as claimed in claim 7 wherein said hydrophobically substituted polyethylene oxide polymer is a polyethylene oxide dioleate ester.

9. The method as claimed in claim 6 wherein said hydrophobically substituted polyethylene oxide polymer is an associative water-soluble polyethylene oxide polymer 15 with urethane linkages. The method as claimed in claim 9 wherein said associative water-soluble polyethylene oxide polymer with urethane linkages is synthesized utilizing isocyanate i: 'compounds. it S 20 11. The method as claimed in claim 10 wherein said isocyanate compounds are selected from the group consisting of hexamethylene diisocyanate, toluene diisocyanate- isophorone diisocyanate, and other dihydroxyl reactive materials.

12. The method as claimed in claim 9 wherein said associative water-soluble polyethylene oxide polymer is synthesized utilizing water-soluble diol compounds, The method as claimed in claim 12 wherein said water-soluble diols are selected from the group consisting f ~ylail/nidk< aapQee l daftpb V 1 w j 36 of polyethylene glycol compounds, and ethylene oxide/propylene oxide block copolymers.

14. The method as claimed in claim 13 wherein said polyethylene glycol compounds have the molecular weight from about 400 to about 1450. The method as claimed in claim 9 wherein said associative water-soluble polyethylene oxide polymer further comprises synthesis utilizing a branching agent.

16. The method as claimed in claim 15 wherein said branching agent is selected from the group consisting of glycerol and pentaerythritol.

17. The method as claimed in claim 9 wherein said associative water-soluble polyethylene oxide polymer with urethane linkages has a molecular weight from about 10,000 to about 2,000,000.

18. The method as claimed in any one of claims 1 to 17 wherein said copolymer or polymer is delivered to said pulp and papermaking system in a carrier solvent. 1i

19. The method as claimed in any one of claims 1 to 17 wherein said hydrophobically modified associative polymer is delivered to said pulp and papermaking system as a powder or a slurry. The method as claimed in claim 18 wherein said carrier solvent is water.

21. The method as claimed in any of claims 1 to 17 wherein said copolymer or polymer is added to said pulp and papermaking system by spraying. Ma8trUnHAeo8/VIG43 03 dam Ob Q? 7 -37

22. The method as claimed in any of claims 1 to 17 wherein said copolymer or polymer is sprayed onto paper machine wire, paper machine felt, paper machine press roll or other surfaces prone to deposition.

23. The method as claimed in any one of claims 1 to 17 wherein said copolymer or polymer is added to said pulp and papermaking systems with the furnish.

24. The method as claimed in any one of claims 1 to 17 wherein said deposition of organic contaminants occurs on the metal surfaces of said pulp and papermaking systems.

25. The method as claimed in any one of claims 1 to 17 wherein said depositions of organic contaminants occurs on the plastic surfaces of said pulp and papermaking systems. 1i 4 15 26. The method as claimed in any one of claims 1 to 17 wherein said copolymer or polymer is added to said papermaking systems with other papermaking treatments.

27. The method as claimed in any one of claims 1 to 17 wherein said organic contaminant is a pitch deposit. 20 28. The method as claimed in any one of claims 1 to 17 wherein said organic contaminant is a stickies deposit. i 29. The method as claimed in any one of claims 1 to 17 wherein said polymer or copolymer is added to the paper machine stock.

30. The method as claimed in any one of claims 1 to 17 wherein said polymer or copolymer is added directly to the contamination prone surface. staBuniaeorJ 3743 93 d.i pb 27 g~ 38

31. surface machine The method as claimed in claim 30 wherein said is selected from the group consisting of paper wire and paper machine wet felt. go on 1 Ono ao *o 0 0 of 0 o 4 oi 4 *4 0r 4

32. The method as claimed in any one of claims 1 to 17 wherein said organic contaminant is a mixture of pitch deposit and stickies deposit.

33. A method for inhibiting the deposition of organic contaminants from secondary fiber during repulping comprising treating said secondary fiber with an effective amount of a hydrophobically substituted acrylamide copolymer.

34. The method as claimed in claim 33 wherein said hydrophobically substituted acrylamide copolymer has the structure: CH 3 0 I II C C C 0 -(CH 2 CH 2 0)24 22 H 4

35. The method as claimed in claim 33 wherein said hydrophobically substituted acrylamide copolymer has the structure: CH3 I C C C 0 II C 0 -(CH 2 CH 2 0)10 0 (CH 2 8 CH 3

36. The method as claimed in claim 33 wherein said hydrophobically substituted acrylamide copolymer has the structure: CH 3 0 I II C C C- [0-C C] 4 CH 3 CH3

37. The method as claimed in claim 33 wherein said slaunhaUWoqiJO 743,93.doini jsb 27. ii 39 hydrophobically substituted acrylamide copolymer has the structure: CH 3 0 C= C C [CH 2 CH 2 0] 6 (CH 2 8 CH 3

38. A method for inhibiting the deposition of organic contaminants from secondary fiber during repulping comprising treating said secondary fiber with an effective 'j amount of hydrophobically substituted polyethylene oxide polymer.

39. The method as claimed in claim 38 wherein said i hydrophobically substituted polyethylene oxide polymer has S 10 hydrophobic groups which are combined to said polyethylene oxide polymer by ester linkages. The method as claimed in claim 39 wherein said hydrophobically substituted polyethylene oxide polymer is a polyethylene oxide dioleate ester.

41. The method as claimed in claim 38 wherein said hydrophobically substituted polyethylene oxide polymer is an associative water-soluble polyethylene oxide polymer with urethane linkages. t

42. The method claimed in claim 41 wherein said associative water-soluble polyethylene oxide polymer with urethane linkages is synthesized utilizing isocyanate compounds.

43. The method as claimed in claim 42 wherein said isocyanate compounds are selected from the group consisting of hexamethylene diisocyante, toluene diisocyanate, ihophorone diisocyanate, and other dihydroxyl reactive materials. st.%unhauoop36743 93 aitrs b 277 40

44. The method as claimed in claim 41 wherein said associative water-soluble polyethylene oxide polymer is synthesized utilizing water-soluble diol compounds. The method as claimed in claim 44 wherein said water-soluble diols are selected from the group consisting of polyethylene glycol compounds, and ethylene oxide/propylene oxide block copolymers.

46. The method as claimed in claim 45 wherein said polyethylene glycol compounds have the molecular weight from about 400 to 1450. It t 4 *t 15 I 54 S.

47. The method as claimed in claim 45 wherein said associative water-soluble polyethylene oxide polymer further comprises synthesis utilizing a branching agent.

48. The method as claimed in claim 47 wherein said branching agent is selected from the group consisting of glycerol and pentaerythritol.

49. The method as claimed in claim 41 wherein said associative water-soluble polyethylene oxide polymer with urethane linkages has a molecular weight from about 10,000 to about 2,000,000. The method as claimed in any one of claims 49 wherein said polymer or copolymer is delivered to secondary fiber in a carrier solvent. 33 to said 7 I ::r

51. The method as claimed in any one of claims 49 wherein said polymer or copolymer is delivered to pulp and secondary fiber as a powder or a slurry. 33 to said

52. The method as claimed in claim 50 wherein said carrier solvent is water. tMatuniaioop/3743 93,dai j b 27.7 r, 41

53. The method as claimed in any one of claims 33 to 49 wherein said polymer or copolymer is added to said pulp and papermaking system by spraying.

54. The method as claimed in any one of claims 33 to 49 wherein said polymer or copolymer is sprayed onto paper machine wire, paper machine felt, paper machine press roll or other surfaces prone to deposition. The method as claimed in any one of claims 33 to 49 wherein said polymer or copolymer is added to said secondary fiber with the furnish. a. (44 15 *444 4

56. The method as claimed in any one 49 wherein said pitch deposition occurs on surfaces of said repulping systems.

57. The method as claimed in any one 49 wherein said pitch deposition occurs on surfaces of said repulping systems.

58. The method as claimed in any one 49 wherein said pitch deposition occurs on surfaices of said repulping systems, of claims 33 to the metal of claims 33 to the metal of claims 33 to the plastic t* U 4. *it 20 59. The method as claimed in any of the preceding claims wherein said pulp and papermaking system is experiencing the effects of dilution. DATED THIS 1ST DAY OF AUGUST 1995. BETZ INTERNATIONAL, INC By its Patent Attorneys: GRIFFITH HACK CO Fellows Institute of Patent Attorneys of Australia stafUuntalkeop/3643.93.daims jb 1.B i. I t ABSTRACT Methods for inhibiting deposition of organic contaminants from pulp in pulp and papermaking systems which comprises treating the pulp and papermaking system with an effective amount of a hydrophobically modified associative polymer. t ,r c t I i t t4t t i t i III' 4 t t II