JP4505130B2 - How to prevent paper stains - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for preventing paper stains, and more particularly to a method for preventing pitch troubles derived from papermaking raw materials mainly composed of used magazine paper by using a specific polymer.
[0002]
[Prior art]
The so-called pitch in the papermaking process is a water-insoluble and sticky substance. This pitch includes those derived from wood and latex and the like used in the papermaking process. Wood origin includes fats and oils, fatty acids, terpenes, steroids, natural resins and gums, and these remain even after pulping. In the later papermaking process, these sticky substances are released and colloidally dispersed, but this colloidal state is destroyed due to strong shearing force, rapid pH change, addition of sulfuric acid band, and the like. It becomes coarse and becomes a so-called pitch. On the other hand, the pitch derived from the paper processing substance is also destroyed in the colloidal state while the latex such as the coat block in the coat paper manufacturing process is recycled at the wet end. Aggregates together with calcium carbonate and coarsens, forming a white pitch deposit on paper after paper making, causing trouble. In factories that produce coated paper, there are cases where calcium carbonate in the coated block constitutes the majority of the ash content in the coated paper, or the coated block is the only source of filler. The ash content in the coat block is more difficult to apply than ordinary internal fillers. This means filler yield rate is low. This is because the pigment particle diameter of the coating grade is generally smaller than the particle diameter for internal addition. For this reason, when the raw material yield decreases, the concentration of white water circulating in the papermaking system is increased to cause filler contamination. In addition, the sizing agent that does not fix is hydrolyzed in the paper making process and causes dirt (pitch trouble).
[0003]
JP-A-4-241184 discloses a method of adding a dimethyldiallylammonium chloride / acrylic acid / (optionally acrylic acid alkyl ester) copolymer to the wet end of a papermaking system in order to suppress natural pitch trouble. Yes. In addition, as a method of removing pitch in pulp derived from raw wood in the bleaching step alkali extraction of pulp production, a copolymer of a water-soluble unsaturated carboxylic acid and a hydrophobic monomer is used as a pulp slurry after bleaching. Is added before entering the next alkali extraction tower (Japanese Patent Laid-Open No. 11-256490). In addition, as a method for preventing troubles caused by various pitches derived from wood or waste paper, polystyrene sulfonic acid (salt) and polyisoprene sulfonic acid (salt) are dissolved in shower water in a place where the pitch easily adheres, It is described that the toner is supplied by a shower, an injection nozzle, a water doctor or the like (Japanese Patent Laid-Open No. 11-189987). As an example of using a cationic polymer, JP-A-11-930911 discloses a method for dissolving a vinyl imidazoline polymer in paper machine washing water as a method for preventing problems in general pitch materials.
[0004]
[Problems to be solved by the invention]
However, regarding the antifouling method derived from the papermaking raw materials mainly composed of used magazine paper, no definite measures have been proposed yet. The subject of this invention is developing the processing method for preventing the stain | pollution | contamination resulting from the pitch derived from used magazine paper.
[0005]
[Means for Solving the Problems]
As a result of detailed studies to solve the above-mentioned problems, it was found that paper stains can be prevented by treating raw pulp with a specific polymerizable cationic polymer, and the present invention has been achieved. That is, according to the first aspect of the present invention, prior to sheet formation, the papermaking raw material mainly composed of used magazine paper contains a dimethyl group containing a repeating unit represented by the following general formula (1) and / or general formula (2). The (co) polymer of diallylammonium chloride and / or the (co) polymer of (meth) acryloyloxyethyltrimethylammonium chloride is supplied to the individual papermaking raw material pulp chest before blending or to the individual papermaking raw material pulp chest piping outlet before blending. A method for preventing paper stains, which comprises making paper after addition and processing.
[Chemical 1]
Repeating unit (1)
R ₁ and R ₂ are hydrogen or a methyl group, R ₃ and R ₄ are a methyl group, an ethyl group and a benzyl group, and Y is an anion
Repeating unit (2)
A is oxygen radicals or NH, B is an alkylene group or an alkoxylene group C ₂ ~C _{3, R 5} is hydrogen or _{methyl, R 6, R 7, R} 8 is a methyl group, an ethyl group, a benzyl group, Y Is anion [000 6 ]
The invention of claim 2, wherein the (co) polymer, with a dispersant presence consisting soluble ionic polymer in salt solution in an aqueous salt solution, the following particle size 100 microns m produced by dispersion polymerization The method for preventing soiling of paper according to claim 1, comprising a dispersion of polymer fine particles.
[000 7 ]
According to a third aspect of the present invention, the (co) polymer comprises (co) polymer and / or (meth) acryloyloxyethyltrimethylammonium containing 10 to 100 mol% of dimethyldiallylammonium chloride and 0 to 90 mol% of acrylamide. 3. The method for preventing soiling of paper according to claim 1 or 2 , which is a polymer or copolymer containing 10 to 100 mol% of chloride and 0 to 90 mol% of acrylamide.
[000 8 ]
The invention according to claim 4 is the paper stain prevention method according to any one of claims 1 to 3, wherein the molecular weight of the (co) polymer is 50,000 or more and 5,000,000 or less.
[000 9 ]
The invention according to claim 5 is the paper stain prevention method according to claim 2 , wherein the ion equivalent of the ionic polymer is 1.5 to 15 meq / g.
[00 10 ]
The invention according to claim 6 is the paper stain prevention method according to claim 2 , wherein the inorganic salt constituting the aqueous salt solution is a polyvalent anion salt.
[00 11 ]
The invention according to claim 7 is characterized in that the (co) polymer containing the repeating unit represented by the general formula (1) and / or the general formula (2) with respect to the dry weight of the papermaking raw material mainly composed of used magazine paper is 0.00. 005 to 0.2% by weight is added. The paper stain prevention method according to any one of claims 1 to 6.
[00 12 ]
DETAILED DESCRIPTION OF THE INVENTION
The cationic water-soluble polymer having a repeating unit represented by the general formula (1) and / or (2) used in the present invention is as follows. The cationic (co) polymer having a repeating unit represented by the general formula (1) is synthesized by (co) polymerizing diallyldimethylammonium chloride or diallylmethylbenzylammonium chloride as a monomer. In addition, the cationic water-soluble polymer represented by the general formula (2) and having a repeating unit includes (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxy 2-hydroxypropyltrimethylammonium chloride as monomers. And (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloylamino [2- (dimethyl) ethyl] trimethylammonium chloride, and the like can be synthesized by (co) polymerization. Examples of nonionic monomers used in the synthesis of copolymers include acrylamide, N, N-dimethylacrylamide, acryloylmorpholine, N-vinylpyrrolidone, acrylonitrile, N-vinylformamide, N-vinylacetamide, and vinyl acetate. The most preferred nonionic monomer is acrylamide.
[00 13 ]
When (co) polymerizing these cationic or nonionic monomers, known polymerization methods can be applied. Examples thereof include an aqueous solution polymerization method, a water-in-oil emulsion polymerization method, a water-in-oil dispersion polymerization method, and a salt aqueous solution dispersion polymerization method. The most preferable product form is a dispersion polymerized product in a salt solution.
[00 14 ]
A water-soluble polymer comprising a polymer dispersion dispersed in an aqueous salt solution can be produced according to JP-A-62-1251. In this method, a cationic monomer or a cationic monomer and a nonionic monomer are stirred in a salt aqueous solution in the presence of a dispersant composed of an ionic polymer soluble in the salt aqueous solution. made from the grain-based 100 microns m or less of the polymer dispersions produced it is also to the. As the dispersant made of an ionic polymer, a homopolymer of dimethyldiallylammonium chloride or (meth) acryloyloxyethyltrimethylammonium chloride or a copolymer with a nonionic monomer is used. The inorganic salts constituting the aqueous salt solution are more preferably polyvalent anion salts, and sulfates or phosphates are suitable. Specifically, ammonium sulfate, sodium sulfate, magnesium sulfate, aluminum sulfate, ammonium hydrogen phosphate, hydrogen phosphate Examples thereof include sodium and potassium hydrogen phosphate, and these salts are preferably used as an aqueous solution having a concentration of 15% or more.
[00 15 ]
To polymerize a dimethyldiallylammonium salt polymer, the monomer aqueous solution is adjusted to pH 2-7 regardless of the polymerization method, the solution is deoxygenated in a nitrogen stream, and then a radical polymerization initiator is added for polymerization. To start. The initiator is a redox system such as a combination of ammonium peroxonisulfate and sodium bisulfite, peroxides such as hydrogen peroxide and lauryl peroxide, solvent-soluble azobisisobutyronitrile, water-soluble 2,2-azo. Polymerization with monomers such as azo compounds such as bisamidinopropane dihydrochloride and 2,2-azobis [2- (5-methyl-2-imidazolidin-2-yl) propane] dihydrochloride, or polymerization Use as appropriate depending on the conditions.
[00 16 ]
When synthesizing a cationic water-soluble polymer having a repeating unit represented by the general formula (1), diallyldimethylammonium chloride is usually used as a monomer, but diallyldimethylammonium chloride has a very slow polymerization rate. Care must be taken when copolymerizing with nonionic acrylic monomers. For example, when copolymerizing with acrylamide, the diallyldimethylammonium chloride to be used is charged into the polymerization system, and acrylamide with a high polymerization rate is supplied continuously or divided and distributed as uniformly as possible in the polymer chain. It is important to carry out such a polymerization operation.
[00 17 ]
On the other hand, when the cationic water-soluble polymer having a repeating unit represented by the general formula (2) is synthesized, (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxy 2-hydroxypropyltrimethylammonium chloride (Meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloylamino [2- (dimethyl) ethyl] trimethylammonium chloride, and the like can be synthesized by (co) polymerization. Since these monomers are excellent in polymerizability and have good copolymerizability with acrylamide and the like, they can be synthesized by performing a general copolymerization operation.
[00 18 ]
The constituent ratio of the repeating unit represented by the general formula (1) in the cationic water-soluble polymer is 10 mol% to 100 mol%, preferably 20 mol% to 100 mol%. If it is less than 10 mol%, the adsorption to the water-insoluble component causing pitch trouble is weak, the aggregation of the water-insoluble component is prevented, and the function of dispersing in water is lowered. The constituent ratio of the repeating unit represented by the general formula (2) in the cationic water-soluble polymer is 10 mol% to 100 mol%, preferably 20 mol% to 100 mol%. If it is less than 10 mol%, the effect is reduced for the same reason as described above. The molecular weight of these cationic water-soluble polymers is 50,000 to 5,000,000, preferably 100,000 to 5,000,000.
[00 19 ]
The addition amount of the cationic water-soluble polymer used in the present invention to the papermaking raw material varies depending on the cation requirement of the papermaking raw material, but is 50 to 2000 ppm as a pure polymer per dry papermaking raw material, preferably 100 to 1000 ppm, most preferably 200 to 700 ppm. The addition amount of the cationic water-soluble polymer is determined by measuring the required cation amount of the papermaking raw material using a PCD-03 type manufactured by Mutech. For example, after adding the polymer of the present invention to the used papermaking raw material and stirring, the Whatman filter paper NO. The raw material is filtered through 41, and the cation requirement and turbidity of the filtrate are measured. Although the place where the turbidity is the lowest is estimated as a guideline of the appropriate addition amount, it cannot be determined accurately unless it is applied to the papermaking site.
[00 20 ]
The cationic water-soluble polymer used in the present invention is more preferably a polymer having a quaternary ammonium base in the molecule. This is presumably because the adsorbing power against dirt components such as pitch is strong, and the effect of preventing the occurrence of defects and the like on the formed paper due to the aggregation of the pitch components. A more preferable product form of the cationic water-soluble polymer is a dispersion polymerized product in a salt solution. The reason for this is that when the dispersion polymer in salt aqueous solution is dissolved in water, the viscosity of the aqueous solution is lower than that of aqueous solution, powder or water-in-oil emulsion polymer, and the dispersion into papermaking raw material is good. Adsorption is also efficient, and the effect is improved compared to other polymerized products.
[00 21 ]
As a place of addition, a remarkable effect is manifested by adding it directly to the raw pulp that causes the most dirt rather than a mixed chest in which various pulps are mixed. Therefore, the “papermaking raw material” defined in the present invention means an individual papermaking raw material before blending, not a blended paper stock before final papermaking. Therefore, as an example of the addition place, the raw material pulp chest intended for processing may be directly or the outlet of the raw material pulp chest pipe.
[00 22 ]
The method for preventing contamination of the present invention also improves the yield rate on the wire. That is, pitch or anionic substances are contained in the old magazine paper that is subject to antifouling treatment. Therefore, before the addition of the water-soluble cationic polymer of the present invention, even if a cationic retention agent is added, it is consumed by the anionic substance and pitch, and the effect of the retention agent cannot be exhibited. As a result, the conventional situation is that the yield on the wire is low. However, the zeta potential on the surface of the pitch substance is neutralized to a certain extent by the formulation of the present invention, and the anion component in the raw material is also neutralized, so that the yield is improved. .
[00 23 ]
【Example】
EXAMPLES Hereinafter, although this invention is demonstrated in more detail with an Example and a comparative example, this invention is not restrict | limited to a following example, unless the summary is exceeded.
[00 24 ]
Synthesis Example 1 Dimethyl diallyl in a 500 mL four-necked flask equipped with a thermometer, a stirrer, a nitrogen introduction tube, a monomer supply tube connected to a peristaltic pump (SMP-21 type, manufactured by Tokyo Rika Kikai Co., Ltd.) and a condenser 18.6 g of ammonium chloride (trade name DADMAC, 65% by weight, manufactured by Daiso, hereinafter abbreviated as DD), 20 g, 30% by weight of acrylamide (trade name, acrylic amide, 50% by weight, manufactured by Nitto Chemical), ion 107 g of exchanged water, 0.18 g of 2-propanol as a chain transfer agent (0.3% based on the total monomers), 0.7 as a polymerization initiator of 2,2-azobisamidinopropane dihydrochloride % Aqueous solution (5 g (0.25% per total monomer)) was charged. While stirring the raw material mixture, the temperature was maintained at 42 ° C. and nitrogen was introduced to allow polymerization to proceed for 30 minutes. Then, 140 g of a 30 wt% aqueous solution of acrylamide was supplied into the flask at 0.58 g per minute for 4 hours. The molar ratio of DD and acrylamide after the end of the supply is 10:90. After completion of the supply, 5 g of a polymerization initiator solution was added in 8 hours. After 12 hours from the start of polymerization, the heat retention was stopped and the polymerization was stopped. Then, the weight average molecular weight was measured by the molecular weight measuring device (DLS-7000 by Otsuka Electronics) by a static light scattering method, and the cation equivalent value (meq / g) of the polymer was measured by the colloid titration method. This polymer is designated as prototype 1. In addition, in the same manner, polymers of each mol% of DD20, 30, 80 were synthesized (referred to as prototypes 2 to 4, respectively). For DD 100 mol% products, 285 g of 30 wt% aqueous solution was prepared and the same amount as above. 2-propanol was added and the initiator was added at the start of polymerization and 8 hours later. The polymerization temperature and polymerization time were synthesized using the same conditions. This polymer is designated as prototype 5. The physical properties of each polymer are shown in Table 1.
[00 25 ]
(Synthesis Example 2) An acryloyloxyethyltrimethylammonium chloride / acrylamide copolymer and a methacryloyloxyethyltrimethylammonium chloride / acrylamide copolymer were synthesized in a molar ratio as shown in Table 1. Prepare 300 g of 20 wt% aqueous solution of each monomer, adjust pH to 5.0 with sulfuric acid, replace with nitrogen at 42 ° C for 30 minutes, and then use 2,2-azobisamidinopropane dihydrochloride as initiator. 3 g (0.1% by weight per monomer) of 2% aqueous solution of was added to initiate polymerization. After maintaining at 42 ° C. for 15 hours, the heating was stopped and the polymerization was terminated. The above polymers are referred to as prototypes 6 to 8 and prototypes 9 to 11. The molecular weight and cation equivalent value were measured in the same manner as in Synthesis Example-1. The results are shown in Table 1.
[00 26 ]
(Synthesis Example 3) Dimethyldiallyl in a 500 mL four-necked flask equipped with a thermometer, a stirrer, a nitrogen introduction tube, a monomer supply tube connected to a peristaltic pump (SMP-21 type, manufactured by Tokyo Rika Kikai Co., Ltd.) and a condenser Ammonium chloride (hereinafter abbreviated as DD) (trade name DADMAC, 65% by weight, manufactured by Daiso) 31.1 g, acrylamide 17.8 g (trade name: acrylic amide, manufactured by Nitto Chemical, 50% product), ion-exchanged water 107.2 g, ammonium sulfate 64.0 g, sodium sulfate 5.8 g, and acryloyloxyethyltrimethylammonium chloride homopolymer 7.3 g (20% by weight solution, viscosity 8530 mPa · s) as a dispersant were each squeezed into the reactor. Was maintained at 42 ° C., and after substituting with nitrogen for 30 minutes, 2,2′-azobis [2- (5-mes Le was 2-imidazolin-2-yl) propane] Two 10% aqueous solution of 0.35 g (relative to the monomer 0.116% chloride hydride) to initiate the addition polymerization of. Separately, 267.2 g of a solution in which 142.1 g of the acrylamide, 27.5 g of ion-exchanged water, 73.3 g of ammonium sulfate, 6.7 g of sodium sulfate, and 17.8 g of a dispersing agent were mixed was prepared. After the start, 53.4 g of this solution was added for 1.5 hours. Thereafter, 106.8 g, 80.1 g and 26.7 g were added at 1.5 hour intervals, respectively. The molar ratio of DD to acrylamide after supplying all the monomers is 10:90. In addition, 0.35 g of the initiator solution was added 4.5 hours after the start. The reaction was stopped 20 hours after the start. After polymerization, the cation equivalent was measured by colloid titration, and the viscosity and weight average molecular weight of the dispersion were measured. This polymer is designated as prototype 12. A molar ratio of DD and acrylamide of 30:70 was synthesized by the same method (prototype 13). The results are shown in Table 1.
[00 27 ]
Synthesis Example 4 A 15% aqueous solution of acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ) homopolymer was added to a five-necked separable flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube. .7 g, ion-exchanged water 139 g, ammonium sulfate 112.5 g, 50% aqueous acrylamide (hereinafter abbreviated as AAM) 175.1 g, and 80% aqueous acryloyloxyethyltrimethylammonium chloride 33.1 g were charged. 1.9 g of a 1% aqueous solution of '-azobis (2-amidinopropane) hydrochloride was added, and polymerization was performed at an internal temperature of 35 ° C for 10 hours. The polymer particle size in the obtained dispersion was 10 μm or less, and the viscosity of the dispersion was 500 cp. Further, the squeeze monomer molar composition is DMQ: AAM = 10: 90 (prototype 14). The results are shown in Table 1.
[00 28 ]
Synthesis Example 5 Acryloyloxyethyldimethylbenzylammonium chloride: DMQ: AAM = 10: 20: 70 (mol%) was synthesized by the same synthesis method as in Synthesis Example 1 (Prototype 15). The results are shown in Table 1.
[00 29 ]
[Table 1 ]
DD: dimethyldiallylammonium chloride,
DMQ: acryloyloxyethyltrimethylammonium chloride DMC: methacryloyloxyethyltrimethylammonium chloride
ABC: acryloyloxyethylbenzyldimethylammonium chloride AAM: acrylamide, molecular weight unit: 10,000, cation equivalent: meq / g
[00 30 ]
(Comparative Synthesis Example 1 ) A dimethylaminoethyl acrylate homopolymer (comparative- 1 ), which is an acrylic monomer of a tertiary amine, in the same manner as in Synthesis Example-2, and the monomer / acrylamide copolymer Polymerized product = 30/70 (comparative- 2 ), dimethylaminoethyl methacrylate homopolymer (comparative- 3 ), and monomer / acrylamide copolymer = 30/70 (comparative- 4 ) were synthesized. did. The results are shown in Table 2.
[00 31 ]
[Table 2 ]
DMA: dimethylaminoethyl acrylate,
DMM: dimethylaminoethyl methacrylate
Cationic equivalent: meq / g, unit of molecular weight: 10,000
[00 32 ]
Examples 1 to 15
100 mL of papermaking raw material made of magazine waste paper (pH 7.24, turbidity 730 FAU, total ss 2.06%, ash content 0.11%, cation requirement 0.045 meq / L, zeta potential -10 to -19 mV), Set in a stirrer and add trial product-1 to trial product-15 in Table 1 to ss and 300 ppm, respectively, and stir at 500 rpm for 60 seconds. After that, NO. The total amount was filtered with 41 (90 mm) filter paper, and the cation required amount of the filtrate was measured with a PCD-03 type manufactured by Mutech, and the turbidity was measured with a HACH, DR2000P type turbidimeter. The results are shown in Table 3.
[00 33 ]
[Comparative Examples 1 to 4 ]
Tests were carried out in the same manner as in Examples 1 to 15 using Comparative- 1 to Comparative- 4 as comparative polymerization polymers. The results are shown in Table 3.
[00 34 ]
[Table 3 ]
Cation requirement: meq / L
Turbidity of the filtrate: FAU
[00 35 ]
Example 16
The test which applied the cationic water-soluble polymer of trial production-11 used in Example 11 to the field of papermaking improvement was done. The implemented papermaking site is the production of medium quality paper by neutral papermaking. As raw material pulp, chemical pulp (BKP) and mechanical pulp (MP) are blended in a certain proportion in the mixed chest in addition to the magazine waste paper. After being transferred, the amphoteric polyacrylamide type paper strength enhancer is 0.2% by weight (the same applies to the following) per dry pulp weight, 0.3% by weight of sulfuric acid band, 5% by weight of talc as a filler, emulsion type rosin sizing agent 0 0.1% by weight and 0.1% acrylic cationic polymer as a sizing agent is added to the papermaking raw material after blending. Thereafter, the papermaking raw material is diluted with white water, and 0.01% by weight of a cationic polymer is added as a yield improver at the screen outlet, and papermaking is performed by a machine. This time, a raw material chest outlet pipe of magazine waste paper was selected as a place for adding the antifouling agent, and 300 ppm was added per dry coat block. It was found that there were 500 to 600 defects (stains) per 100,000 meter before addition of the antifouling agent of the present invention, but 15 or less after addition.

Claims (7)

Prior to sheet formation, a (co) polymer of dimethyldiallylammonium chloride containing a repeating unit represented by the following general formula (1) and / or general formula (2) in a papermaking raw material mainly composed of magazine waste paper, and (Or) A (co) polymer of (meth) acryloyloxyethyltrimethylammonium chloride is added to the individual papermaking raw material pulp chest before blending or the individual papermaking raw material pulp chest piping outlet before blending , and then papermaking is performed. Paper smear prevention method.
Repeating unit (1)
R ₁ and R ₂ are hydrogen or methyl group, R ₃ and R ₄ are methyl group, ethyl group, benzyl group, Y is an anion
Repeating unit (2)
A is oxygen radicals or NH, B is an alkylene group or an alkoxylene group C ₂ ~C _{3, R 5} is hydrogen or _{methyl, R 6, R 7, R} 8 is a methyl group, an ethyl group, a benzyl group, Y Is anion The (co) polymer is, with a dispersant presence consisting soluble ionic polymer in salt solution in an aqueous salt solution, particle size 100 microns m produced by dispersion polymerization
2. The method for preventing paper stains according to claim 1, comprising a dispersion of the following polymer fine particles. The (co) polymer contains 10 to 100 mol% of dimethyldiallylammonium chloride and 0 to 90 mol% of acrylamide, and / or 10 to 100 mol% of (meth) acryloyloxyethyltrimethylammonium chloride. The method for preventing soiling of paper according to claim 1 or 2 , which is a polymer or copolymer containing 0 to 90 mol% of acrylamide. The method for preventing paper stains according to any one of claims 1 to 3 , wherein the (co) polymer has a molecular weight of 50,000 to 5,000,000. The method for preventing paper stains according to claim 2 , wherein the ion equivalent of the ionic polymer is 1.5 to 15 meq / g. The method for preventing paper stains according to claim 2 , wherein the inorganic salt constituting the aqueous salt solution is a polyvalent anion salt. 0.005 to 0.2% by weight of the (co) polymer containing the repeating unit represented by the general formula (1) and / or the general formula (2) with respect to the dry weight of the papermaking raw material mainly composed of used magazine paper The method for preventing paper stains according to any one of claims 1 to 6 , which is added.