JPH048556B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to pitch control in pulp and paper production. It is well known that "pitch" can accumulate in paper manufacturing and also in pulp manufacturing and can cause serious problems. What is “Pituchi”?
A term used to describe sticky substances that appear in paper manufacturing; these originate from the wood from which the paper is made. However, as more and more recycled paper is used today, "Pituchi"
It is now used as a general term for all substances that are soluble in organic solvents but not in water, such as inks or adhesives present in recycled paper. Pitches can accumulate at various locations in the system. For example, it blocks the felt and prevents drainage of wet paper. In addition, it can stick to the screen or drying cylinder and cause holes in the paper. Deposits may also accumulate at any earlier stage in the paper manufacturing process. When these deposits break off, they can form defects in the paper, such as spots or holes.
Such defects can even create enough weakness in the paper to lead to paper failure during manufacturing, resulting in unwanted manufacturing down time. Many substances have been used in an attempt to eliminate these problems. Such substances are inorganic processing agents,
Examples include talc and anionic dispersants. However, conventional dispersants may not be effective in closed systems because "pitch" buildup is possible. In such systems, pitch particles must be removed from the water system in a controlled manner without allowing them to accumulate on felts or rolls or on the piping used, for example, in paper-making machinery. . These products have also been found to have limited effectiveness and there is a need for further improved treatments. It has now been found, in accordance with the present invention, that certain water-soluble allylamine polymers are particularly effective for this purpose. The present invention therefore provides a method for the suppression of pitch in a water system used in pulp or paper manufacturing, which system or pulp or paper manufacturing machinery contains the formula:

[expression] or

[Formula] In the formula, each of R ₁ and R ₂ independently represents hydrogen or methyl, and X is hydrogen, -(CH ₂ CH ₂ NH) _o H or -(CH ₂ CH ₂ CH ₂ NH) _o H a water-soluble substantially linear polymer or copolymer, or an acid addition salt thereof, having a repeating unit of 0 or 1, preferably 1, and n represents 1 to 3, preferably 1; or by adding a quaternary ammonium salt. It will, of course, be understood that the presence of a cyclic structure does not mean that the polymer is cross-linked and is therefore substantially linear. A special feature of the products used in the present invention is that they bind dissolved anionic substances originating from the wood from which the pulp and paper are manufactured and remove these anionic substances, thus eliminating such substances in the process water. It is possible to provide a method for reducing the concentration of a substance. Water-soluble anionic substances are released from wood during pulping. These components adversely interfere with paper manufacturing in several ways: they reduce the efficiency of many additives used in the paper manufacturing process and change the properties of the paper. Examples of such additives include size, wet and dry strength agents and dyes. Anionic dissolved substances also reduce preservative efficiency. They limit the extent to which the water system can be a closed system, and they can also reduce the quality of the paper, such as its strength. 49-66 of TAPPI Paper Manufacturers Conference 1979 further discussing the importance of anionic dissolved substances.
Cite the page. The polymer used in the present invention is (meta)
Polymers and copolymers of allylamine, vinylamine and di(meth)allylamine. Copolymers which may be used are in particular copolymers derived from allylamine and diallylamine, and copolymers whose comonomer is sulfur dioxide or acrylamide. The proportion of non-allylic amine monomer in this copolymer is preferably 50 mol%
and preferably does not exceed 25 mol%. One or more nitrogen atoms in the polymer may be quaternized or in the form of an acid addition salt. When X represents hydrogen, the side chain is, for example, in the case of a diallyl unit or in the case of monoallylic units. It has been concluded by Here, R ₃ , R ₄ and
Each of R ₅ independently represents hydrogen, a straight-chain or branched alkyl or hydroxyalkyl group containing 1 to 5 carbon atoms, an optionally substituted benzyl group or a cyclohexyl group, or
R ₃ and R ₄ together with the nitrogen atom form a morpholino or piperidino ring, and Y represents an anion, typically chlorine, bromine, iodine, nitric acid, hydrogen sulfate or dihydrogen phosphate. _R3 , _R4 and _R5
Preferred values include hydrogen, methyl, hydroxyethyl and hydroxypropyl. A particularly preferred quaternary group is trimethylamino. X is -(CH ₂ CH ₂ NH) _o H or -
(CH ₂ CH ₂ CH ₂ NH) _o When representing H, the terminal nitrogen atom may be quaternized in a similar manner with similar substituents and anions or in the form of an acid addition salt. By varying the relative proportions of quaternized and non-quaternized amino groups, a whole range of different polymers can be produced to suit individual circumstances. Preferred polymers that can be used include poly(allylamine) hydrochloride, copolymers of allylamine hydrochloride and diallylamine hydrochloride, and copolymers of diallylamine hydrochloride and sulfur dioxide. The molecular weight of the polymers commonly used will be from 5,000 to 500,000, preferably from 25,000 to 100,000, and especially from 50,000 to 100,000. Typical polymers that can be used include, for example, 7500 to
It may have a molecular weight of 85,000. The polymers used in the present invention are generally prepared by combining an inorganic acid salt of a suitable monomer, such as allylamine hydrochloride, in the presence of a radical polymerization initiator having an azo group or a cationic nitrogen atom, generally in a polar solvent such as water, an inorganic Alternatively, it can be produced by polymerization in an aqueous solution of an organic acid, dimethylformamide or dimethylsulfoxide. Typical initiators that can be used are:
2,2'-diamidinyl-2,2'-azopropane hydrochloride. Copolymers can be obtained in a similar manner by radical initiation. Further details regarding the production of such polymers can be found in, for example
Can be found in EP140309 and 142962.
As indicated, the polymer should be substantially linear without crosslinking. Polymers in which X represents an aminoalkyl group can generally be obtained from corresponding polymers in which X is hydrogen. For example, by cyanoethylation,
A polymer is formed which is CH ₂ CH ₂ CN, which is
For example, catalytic hydrogenation can be carried out with Raney nickel. Alternatively, the starting polymer can be modified in this case by reaction with, for example, acrylamide.
It can be converted to an amide of CH ₂ CH ₂ CONH ₂ which can be subjected to Hofmann degradation, for example with hypochlorite and alkali. Of course, these are all well-known reactions. The polymer is generally added to the water system containing the paper pulp, but it is also possible to add it at different points in the system depending on the exact nature of the problem. The pulp will generally be present in an amount of 0.5 to 10%, more typically 0.5 to 5% by weight based on the weight of water. The amount of polymer required will, of course, depend in part on the nature of the wood or other material used to make the paper pulp. Also,
Once added, some of the polymer will tend to be recycled through the system, thus allowing for lower addition rates. However, generally 0.1 to 20 ppm of polymer by weight based on the aqueous medium is suitable. Preferably, this amount is between 1 and
It is 10ppm. In normal cases this corresponds to an addition of 10 to 2000 grams, preferably 100 to 1000 grams, of polymer per ton of fiber. However, if the polymer is required to neutralize anionic dissolved substances, higher amounts are generally desirable, typically per ton of fiber depending on how the fiber is manufactured. 1000
(For a discussion of the amounts of anionic substances that tend to be present, see e.g. Progr. Colloid & Polymer Sci. 65 , 251-
264 (1978)). Fibers produced by mechanical methods generally require higher loadings than fibers produced by chemical methods. Of course, it is also possible to neutralize only a portion of the total amount of dissolved anionic substance. In such cases, even a small amount, for example 10 grams per ton of paper, may be effective. At times it is preferable to spray the reaction products used in the invention onto special parts of pulp or paper manufacturing machinery, such as gauze or press felts. In such a case,
The polymer is preferably prediluted with water, generally to a concentration of less than 10% by weight and preferably from 1 to 5% by weight. In some cases it may be advantageous to add the present polymers together with fungicides, especially slime inhibitors, used in the paper making industry. Examples of suitable fungicides include those in the following classes: () Substituted 5- or 6-membered heterocyclic compounds in which the heteroatoms are one or more nitrogen, Compounds which are oxygen or sulfur and the substituent is an alkyl, keto or hydroxyl group or a halogen atom, such compounds are isothiazolones and in particular those of the formula: In the formula, R represents hydrogen or chlorine. Mixtures of these two isothiazolones are commercially available,
The weight ratio of chlorine-substituted to unsubstituted compounds is about 2.66:1; () Amides, including amines or 2,2-dibromo-3-nitrilopropionamide; () Organic cyanides or thiocyanates, especially Methylene bis(thiocyanate); () Sulfones, including halosulfones, especially hexachlorodimethylsulfone; () Straight-chain aliphatic aldehydes, especially glutaraldehyde; () Triazines, especially thio- and/or amino-substituted alkyltriazines; () Bisbromoacetoxybdenum and () dithiocarbamates, especially monomethyl, dimethyl, monoethyl and diethyl derivatives, typically in the form of the sodium salt. Other agents may optionally be added, especially when the composition is used as a spray, such as corrosion inhibitors to protect the metal substrate, thickeners to increase the contact time between the composition and the equipment. agent,
and surfactants such as amine oxides to improve device wetting. Corrosion inhibitors suitable for use in this method include alkanolamine salts of arylsulfonamide carboxylic acids, such as the commercially available product Hostacor KS1-X from Hoechst. Preferred surfactants for use in this method are n-alkylethoxydimethylamine oxides in which the alkyl has between about 12 and about 18 carbons, such as those described by Albright and Wilson.
Empigen OY (25% concentration), a product commercially available from Albright &Wilson; and Empigen OB (30% concentration), a product commercially available from Albright & Wilson.
including. The polymers are generally compatible with conventional pulp and paper making additives. These additives are
Starches, such as potato or corn starch, titanium dioxide, antifoam agents, such as fatty alcohols, sizes, such as rosin sizes based on abietic acid, neutral sizes based on alkyl ketene dimers or succinic anhydride. sized and wet strength resins, such as epichlorohydrin polyamide if neutral, or melamine or urea formaldehyde resins if acidic. The exact nature of the PH of the system is not important, as the effectiveness of the polymer is not substantially affected by changes in PH. Some of the polymers used in the present invention typically range from 40 to 50% by weight.
It is commercially available as an aqueous solution containing a concentration of about 45%. Typically, the compositions used in the invention will contain from 1 to 70%, especially from 10 to 30%, by weight of the polymer. The following examples further illustrate the invention. Example Ch E
Farley) 1977 TAPPI Paper Manufacturers Conference 23−
Polyallylamine hydrochloride was evaluated along with commercially available pitch suppressants using essentially the method described on page 32. This method is a recognized method for evaluating the sedimentation properties of pitches.
It is based on the TAPPI standard method RC324. A standard pitch solution was prepared as described in the reference above. Synthetic pitch emulsion/dispersion is
Various return waters (back water) from commercial paper manufacturers
1 liter of water) is made into a synthetic pitcher at 50℃.
The concentration was adjusted by adding 1200 ppm. A solution of calcium chloride was added to reach a hardness of 377 ppm expressed as calcium carbonate.
The pH was adjusted to 8.0. To evaluate the product as a pitch suppressant, the product was added to obtain the concentration of polymer as specified in the table. Pitch deposition was evaluated according to the procedure cited in the above reference. The test period was always 5 minutes. The results are shown in the table below (mg of pitch deposited).

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Claims (1)

[Scope of Claims] 1. A method for the suppression of pitch in a water system used in pulp or paper production, which system or pulp or paper production machinery contains the formula: [Formula] or [Formula] In the formula, each of R ₁ and R ₂ independently represents hydrogen or methyl, and X is hydrogen, -(CH ₂ CH ₂ NH) _o H or -(CH ₂ CH ₂ CH ₂ NH) _o H , x represents 0 or 1, and n represents 1 to 3, or an acid addition salt or quaternary ammonium salt thereof. A method consisting of adding 2. The method of claim 1, wherein the polymer is poly(allylamine) hydrochloride. 3. The polymer is a combination of allylamine and diallylamine, diallylamine and acrylamide,
Or the method according to claim 1 or 2, which is a copolymer of diallylamine and sulfur dioxide. 4. The method according to any one of claims 1 to 3, wherein the polymer has a molecular weight of 7,500 to 85,000. 5. A method according to any of claims 1 to 4, wherein the polymer is sprayed onto at least a portion of pulp or paper making machinery. 6. A composition suitable for use in pulp or paper production, comprising a polymer as defined in any of claims 1 to 4 and a slimecidal agent.