JP2010032618A - Electrophotographic transfer paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic transfer paper hardly causing decrease in friction or contamination in a paper making machine but having electrophotographic adaptability such appropriate sizing property and good conveying property even when calcium carbonate is compounded at a high rate as a filler, and having inkjet printing adaptability. <P>SOLUTION: The electrophotographic transfer paper contains an additive for paper making, which is a mixture of a copolymer and a filler, in base paper, and is produced by applying and drying a surface treating agent on the base paper, and is characterized in that: the copolymer is obtained by polymerizing a monomer component containing at least a hydrophobic monomer (A) and a cationic monomer (B) and has a quaternary rate of ≥40 mol%; and the surface treating agent contains a conducting agent. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrophotographic transfer paper, and more particularly to an electrophotographic transfer paper that exhibits a size effect without causing a reduction in friction coefficient and soiling of a paper machine.

  In recent years, in the manufacture of paper, the transition to neutral papermaking is progressing instead of conventional acidic papermaking. In neutral papermaking, smoothness can be increased, and a large amount of calcium carbonate that is highly opaque and inexpensive can be used. In recent years, the amount of calcium carbonate to be blended in electrophotographic transfer paper has gradually increased. Yes.

  On the other hand, paper that has been printed with an electrophotographic method, if its size (water absorption resistance) is insufficient, causes ink bleeding and fluffing after printing. Securing of sex is required. Also, in electrophotographic transfer paper, the decrease in friction coefficient is caused by transportability such as double feeding (a phenomenon in which two or more sheets are fed when feeding inside the machine) and jam trouble (paper jam). There is a fear of causing deterioration.

  Furthermore, the electrophotographic transfer paper is required to be a common paper that can be used for an ink jet recording method. In the ink jet recording system, by ejecting micro droplets of ink from the ink nozzles by individual mechanisms and attaching them onto the recording paper, dots are formed and recorded and held on the paper surface, so the ink is quickly absorbed, There is a demand for paper that is suitable for ink jet printing that does not cause a decrease in printing density, bleeding, and feathering, which is bleeding. In recent years, recording systems have been actively developed to reduce the size and price of copiers, printers, and facsimiles, and to achieve higher color and higher image quality. Requests are changing.

In general, neutral sizing agents using rosin esters, reinforced rosin esters, etc., ASA (alkenyl succinic anhydride), AKD (alkyl) are used as internal sizing agents to be added to impart size to neutral papermaking. Ketene dimer) is used. However, in the recent paper making method using a large amount of filler, especially calcium carbonate, when neutral rosin known as an internal sizing agent is used, the effect of neutral rosin is significantly reduced to ensure the required size. In addition, when neutral rosin is blended in a high amount, papermaking stains and chemical costs increase. Neutral rosin requires the addition of aluminum sulfate in order to develop size, but if aluminum sulfate is increased in order to improve size, the pH of the papermaking system will drop and calcium carbonate will dissolve. Gypsum precipitates, causing defects and paper breaks. On the other hand, when AKD is used, if the added amount is large, the paper machine becomes dirty, and the rise in size is slow. It drops significantly. On the other hand, when ASA is used in a large amount, the paper machine tends to get dirty more than neutral rosin and AKD, resulting in frequent defects and paper breaks.
Therefore, a technique has been proposed that aims to improve the yield of the filler itself or the paper strength. For example:
(1) Patent Document 1

It is described that cationic calcium carbonate coated and adsorbed with a cationic polymer or an amphoteric polymer is blended in a pulp slurry to suppress filler yield and paper strength reduction (claim 1, paragraph [0007]). . Further, as Example 1, it is described that light calcium carbonate is coated with a water-soluble polymer of dimethylaminoethyl acrylate and acrylamide and added to a pulp slurry.
(2) Patent Document 2
It is described that the filler is treated with starch and an organic polymeric material (eg, polyacrylamide (PAM)).
(3) Patent Document 3

According to the method for producing a filler in which a solution obtained by dispersing a cellulose reactive sizing agent such as AKD or ASA in water with a dispersing agent such as cationic starch is contacted with a filler such as calcium carbonate. It is described that a decrease in size can be suppressed.
(4) Patent Document 4
It is described that the required amount of sizing agent can be reduced by using a filler (preferably PCC (precipitated calcium carbonate)) treated with cation-modified AKD.
(5) Patent Document 5
In the presence of metal ions (aluminum, barium, lithium, magnesium and other ions, C _{12 to} C ₂₂ water-soluble fatty acid salts (preferably fillers coated with sodium stearate (calcium carbonate, clay, titanium oxide, etc. It is described that the adsorption of the internally added sizing agent can be suppressed.

Japanese Patent Laid-Open No. 04-281094 JP-A-56-049097 Japanese Patent Laid-Open No. 04-228697 Japanese Patent Laid-Open No. 05-247886 Japanese National Patent Publication No. 08-507837

  The above-mentioned Patent Document 1 secures the yield and paper strength of the filler itself by pretreatment with cationic or amphoteric polyacrylamide, and is a hydrophilic polymer, so that it can impart hydrophobicity to the filler and paper. There is no effect of suppressing the paper size reduction. The above Patent Document 2 is also a pretreatment method using starch and a cationic organic polymer electrolyte in combination, and intends to give the same effect as the above Patent Document 1.

The above Patent Documents 3 to 4 are intended to improve hydrophobicity by pretreating a filler with a reactive sizing agent such as AKD or ASA, or cation-modified AKD. If is relatively high, there is a high risk of inducing paper slippage problems and contamination problems in the papermaking process.
In addition, Patent Document 5 covers a filler with a fatty acid salt and is effective as a technique for suppressing adsorption of an internally added sizing agent to a filler having a large specific surface area. It may change the state in the process and affect the effect of chemicals.

Furthermore, since the molecular weight of the treating agent for pretreating the filler in the above technique is in a relatively low range, if the electrical conductivity in the papermaking process is high and the amount of anionic trash is large, the filler, pulp fiber and treating agent The interaction with itself may be hindered and the performance may be reduced.
As described above, it is difficult to cope with the adverse effects caused by the existing sizing system using a high filler. If these problems can be solved and a desired sizing degree can be obtained, the printing aptitude and pen writing aptitude are improved. In addition, the use of fillers can be expected to increase the effect of preventing strikethrough.

  Therefore, the problem of the present invention is that even when calcium carbonate is highly blended as a filler, there is little decrease in friction and dirt on the paper machine, it has electrophotographic suitability such as moderate size and good transportability, and Another object is to provide an electrophotographic paper having ink jet printing suitability.

In order to solve the above problems, the electrophotographic transfer paper of the present invention is characterized by the following constitution.
(1) The electrophotographic transfer paper of the invention according to claim 1 contains an additive for papermaking which is a mixture of a copolymer and a filler in the base paper, and is coated with a surface treatment agent and dried on the base paper. Paper, wherein the copolymer is a copolymer having a quaternization rate of 40 mol% or more obtained by polymerizing a monomer component containing at least a hydrophobic monomer (A) and a cationic monomer (B), The surface treatment agent includes a conductive agent.
(2) The electrophotographic transfer paper of the invention according to claim 2 is characterized in that the copolymer is a cationic copolymer or an amphoteric copolymer containing an anionic monomer (C).
(3) In the electrophotographic transfer paper of the invention according to claim 3, the ratio of the anionic equivalent derived from the anionic monomer (C) to the cationic equivalent derived from the cationic monomer (B) in the amphoteric copolymer is 0. It is obtained by polymerizing a monomer component of 0.1 to 90%.
(4) The electrophotographic transfer paper of the invention according to claim 4 is characterized in that the filler contains 10 to 30% by weight of calcium carbonate as ash in the paper.

  The present invention provides a copolymer having a quaternization ratio of 40 mol% or more obtained by polymerizing a monomer component containing at least a hydrophobic monomer (A) and a cationic monomer (B) even if the copolymer has a high ash content. Since it is a polymer and the surface treatment agent contains a conductive agent, the filler can be provided with an appropriate water repellency, and the filler having the water repellency is efficiently adsorbed to the anionic pulp fibers. Even with high ash content, it has moderate sizing, good electrophotographic suitability, and ink jet suitability without causing a decrease in friction when using AKD and soiling of the paper machine when using ASA. An electrophotographic transfer paper can be obtained.

1. Pretreated filler: paper additive The first paper additive used in the present invention is a filler pretreated with a cationic copolymer having a quaternization rate of a specified value or more as an active ingredient, The second additive for papermaking has as an active ingredient a filler pretreated with an amphoteric copolymer having a quaternization ratio of a specified value or more and a ratio of anion equivalent to cation equivalent within a predetermined range. The electrophotographic transfer paper is a paper made by adding these papermaking additives to pulp slurry.
When a cationic or amphoteric copolymer containing a hydrophobic group-containing monomer as an essential component is mixed with a filler (pretreatment), and the filler is given appropriate water repellency, the filler imparted with water repellency becomes anionic. Efficiently adsorbs to the pulp fibers, giving the paper an effective size. According to this filler, it is possible to ensure sufficient sizing properties without using an internal sizing agent or reducing the weight, so that the paper machine is less likely to become dirty, and compared with the internal sizing agent. High sizing can be obtained with a small amount.

(First paper additive)
In the first papermaking additive used in the present invention, the cationic copolymer used for the pretreatment is obtained by polymerizing monomer components essentially comprising the hydrophobic monomer (A) and the cationic monomer (B). The classification rate is 40 mol% or more.
The hydrophobic monomer (A) is styrene or a derivative thereof, (meth) acrylonitrile, an alkyl ester of (meth) acrylic acid, etc., and in particular, styrene or a derivative thereof, (meth) acrylonitrile, C of (meth) acrylic acid. ₁ -C ₁₂ alkyl esters are preferred.
In the present invention, “(meth) acryl” means “acryl” or “methacryl”. Similarly, “(meth) acrylo” means “acrylo” or “methacrylo” and “(meth) ) Acrylate "means" acrylate "or" methacrylate ".

Examples of the styrene or derivatives thereof include styrene, α-methyl styrene, vinyl toluene, ethyl vinyl toluene, chloromethyl styrene, vinyl pyridine and the like, and styrene is preferable.
Examples of the (meth) _C 1 _{-C 12} alkyl esters of acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n- butyl (meth) acrylate, iso- butyl (meth) acrylate , Hydrocarbon esters such as t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and the like. A (meth) acrylic acid ester containing a cyclic or aromatic hydrocarbon group can also be used. Particularly preferred are methyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and lauryl (meth) acrylate.

  The cationic monomer (B) contains a primary to tertiary amino group-containing (meth) acrylamide, a primary to tertiary amino group-containing (meth) acrylate, a quaternary ammonium base-containing (meth) acrylamide, and a quaternary ammonium base (meta). ) One or more cationic groups in the molecule, such as acrylate, diallyldialkylammonium halide, etc., especially tertiary amino group-containing (meth) acrylamide, tertiary amino group-containing (meth) acrylate Diallyldialkylammonium halides are preferred.

Examples of the tertiary amino group-containing (meth) acrylamide include dimethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, diethylaminopropyl (meth) acrylamide, and dialkylaminoalkyl (meth) acrylamide. Etc.
As the tertiary amino group-containing (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminoethyl (meth) acrylate, diethylaminopropyl (meth) acrylate, dialkylaminoalkyl (meth) acrylate Etc.

The primary or secondary amino group-containing (meth) acrylamide is a primary amino group-containing (meth) acrylamide such as aminoethyl (meth) acrylamide, or methylaminoethyl (meth) acrylamide, ethylaminoethyl ( Secondary amino group-containing (meth) acrylamides such as meth) acrylamide and t-butylaminoethyl (meth) acrylamide are exemplified.
Examples of the primary or secondary amino group-containing (meth) acrylate include primary amino group-containing (meth) acrylates such as aminoethyl (meth) acrylate, methylaminoethyl (meth) acrylate, and ethylaminoethyl (meth). Examples thereof include secondary amino group-containing (meth) acrylates such as acrylate and t-butylaminoethyl (meth) acrylate.

  As the quaternary ammonium base-containing (meth) acrylamide and quaternary ammonium base-containing (meth) acrylate, tertiary amino group-containing (meth) acrylamide or tertiary amino group-containing (meth) acrylate, methyl chloride, benzyl chloride, Mono-quaternary base-containing monomers quaternized with a quaternizing agent such as methyl sulfate or epichlorohydrin. Specifically, acrylamidopropyltrimethylammonium chloride, acrylamidopropylbenzyldimethylammonium chloride, methacryloyloxyethyldimethylbenzylammonium chloride, acryloyloxyethyldimethylbenzylammonium chloride, (meth) acryloylaminoethyltrimethylammonium chloride, (meth) acryloyl Examples include aminoethyltriethylammonium chloride, (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxyethyltriethylammonium chloride, and the like.

As the monomer component constituting the cationic copolymer, in addition to the hydrophobic monomer (A) and the cationic monomer (B), other vinyl monomers excluding the anionic monomer may be used as necessary. Can do.
Examples of other monomers include hydroxyl-containing (meth) acrylates such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate, (meth) acrylamide, dimethyl (meth) acrylamide, diethyl (meth) acrylamide, and iso-propyl. Examples include amide group-containing monomers such as (meth) acrylamide and vinyl acetate.
The monomer component constituting the cationic copolymer can be used alone or in combination. The composition ratio of the monomer component can be arbitrarily set within a range in which appropriate water repellency can be imparted to the filler, but the content of the hydrophobic monomer (A) is about 60 to 90% by weight, and the content of the cationic monomer (B) Is preferably about 10 to 40% by weight.

(Second paper additive)
On the other hand, in the second papermaking additive used in the present invention, the amphoteric copolymer used for the pretreatment essentially comprises a hydrophobic monomer (A), a cationic monomer (B) and an anionic monomer (C). In addition, a monomer component in which the ratio of the anion equivalent of the monomer (C) to the cation equivalent of the monomer (B) is in a predetermined range is polymerized to make the quaternization rate 40 mol% or more.
Examples of the anionic monomer (C) include α, β-unsaturated carboxylic acids and α, β-unsaturated sulfonic acids.

Examples of the α, β-unsaturated carboxylic acids include (meth) acrylic acid, (anhydrous) maleic acid, fumaric acid, itaconic acid, (anhydrous) citraconic acid, its sodium, potassium, and ammonium salts.
Examples of the α, β-unsaturated sulfonic acids include vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, sulfopropyl (meth) acrylate, 2- (meth) acrylamide-2-methylpropane sulfonic acid, and salts thereof Etc.

Among the monomer components constituting the amphoteric copolymer, the hydrophobic monomer (A) and the cationic monomer (B) are monomer components constituting the cationic copolymer in the first paper additive of the present invention. As described above. Moreover, the point which can use other vinyl monomers other than an essential monomer is the same as that of the case of a 1st papermaking additive.
In the case of the monomer component constituting the amphoteric copolymer, each monomer can be used alone or in combination. The composition ratio of the monomer component can be arbitrarily set within a range in which appropriate water repellency can be imparted to the filler, but the content of the hydrophobic monomer (A) is about 60 to 90% by weight, and the content of the cationic monomer (B) Is preferably about 20 to 40% by weight, and the content of the anionic monomer (C) is preferably about 0.2 to 10% by weight.

  In the monomer component constituting the amphoteric copolymer, the ratio of the anionic equivalent derived from the anionic monomer (C) to the cationic equivalent derived from the cationic monomer (B) needs to be 0.1 to 90%. It is. A preferable equivalent ratio is 5 to 20%, more preferably 5 to 15%. That is, the amphoteric copolymer in the present invention is more likely to exhibit a size effect when the cation equivalent is rich and the anion equivalent is small. If the ratio of the anion equivalent to the cation equivalent is too large, the anionic monomer (C) forms an ionic complex with the cation portion, which reduces the action of the cation on the pulp fiber, and there is a possibility that the size property will not be expressed. An anionic equivalent of the anionic monomer (C) within the above range is required.

(Quaternization)
It is important that the quaternization rate of the cationic copolymer or amphoteric copolymer is 40 mol% or more. The quaternization rate is preferably 50 to 100 mol%. If the quaternization rate is less than 40 mol%, it may be difficult to obtain an effective water repellency imparting effect to the filler and pulp fiber.
In quaternization of the cationic copolymer or amphoteric copolymer, for example, a monomer component containing a tertiary amino group-containing monomer as the cationic monomer (B) is polymerized, and then the obtained copolymer is converted to 4 It may be quaternized with a classifier, or may be polymerized using a quaternary ammonium base-containing monomer obtained by quaternization in advance as the cationic monomer (B). As the quaternizing agent, methyl chloride, benzyl chloride, epichlorohydrin and the like can be used.

(Filler)
In the first and second papermaking additives of the present invention, any known filler can be optionally used as a filler to be mixed (pretreated) with the cationic copolymer or amphoteric copolymer. For example, calcium carbonate, clay, silica, kaolin, magnesium carbonate, barium carbonate, barium sulfate, aluminum hydroxide, zinc oxide, titanium oxide and other inorganic fillers, urea-formalin resin, melamine resin, polystyrene resin, phenol resin, etc. Organic fillers can be used alone or in combination. In addition, recycled fillers made from papermaking sludge, deinking floss, etc. can also be used. In the present invention, calcium carbonate is used because the cationic copolymer and amphoteric copolymer in the present invention are excellent in action on calcium carbonate, and calcium carbonate is inexpensive and excellent in optical properties. It is preferable. As the calcium carbonate, spindle-shaped or rosetta-type plasma calcium carbonate, in which the strikethrough is remarkably improved by the interaction with the internally added sizing agent, is preferable. Further, a calcium carbonate-silica composite (for example, a light calcium carbonate-silica composite disclosed in Japanese Patent Laid-Open No. 2003-212539 or Japanese Patent Laid-Open No. 2005-219945) can also be used.

The pretreatment of the filler with the cationic copolymer or amphoteric copolymer is usually performed by mixing and stirring the aqueous solution of the copolymer and the filler slurry in advance before adding to the pulp slurry. The mixing temperature is preferably about 10 to 50 ° C., and the mixing time is preferably 1 minute or more.
The ratio of the copolymer to 100 parts by weight of the filler when mixing the cationic copolymer or amphoteric copolymer and the filler is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight. Part, more preferably 0.2 to 2 parts by weight. If the proportion of the copolymer is too small, a sufficient size effect may not be obtained. On the other hand, even if the proportion of the copolymer is made larger than the above range, there is not much change in the obtained size improvement effect, and the cost tends to be wasted.

2. Production of electrophotographic transfer paper The electrophotographic transfer paper of the present invention is produced by adding the papermaking additive to a pulp slurry and wet-making it.
(Addition amount)
In the present invention, a copolymer and a filler are mixed to form a paper additive, and an additive form in which a paper additive is added to a pulp slurry is taken. It is usually preferable to contain 0.05 to 0.5 parts by weight. More preferably, the content is 0.10 to 0.3% by weight based on the absolute dry weight of pulp. If the amount is less than 0.05% by weight, there is a fear that the effect of the sizing agent may not be obtained.

(pulp)
The pulp fiber constituting the pulp slurry is not particularly limited, and wood pulp such as NBKP and LBKP, mechanical pulp such as TMP and GP, deinked pulp (DIP), and linter pulp that are usually used for papermaking. Non-wood pulp such as hemp, bagasse, kenaf, esparto grass and straw, semi-synthetic fibers such as rayon and acetate, synthetic fibers such as polyolefin, polyamide and polyester can be used.

(Filler)
In the present invention, a filler may or may not be blended separately from the paper additive. When the filler is blended, the filler generally used in acidic papermaking or neutral papermaking can be used, and is not particularly limited. For example, in neutral papermaking, clay, kaolin, calcined kaolin, deramikaolin, heavy calcium carbonate, light calcium carbonate, magnesium carbonate, barium carbonate, titanium dioxide, zinc oxide, silicon oxide, amorphous silica, aluminum hydroxide, Inorganic fillers such as calcium hydroxide, magnesium hydroxide, and zinc hydroxide, and organic fillers such as urea-formalin resin, polystyrene resin, phenol resin, and fine hollow particles are used singly or in appropriate combination of two or more. In acidic papermaking, a filler obtained by removing acid-soluble ones from the filler used in the neutral papermaking is used, and these are used alone or in appropriate combination of two or more. From the viewpoint of smoothness and opacity, the blending amount of the filler is preferably 2 to 30% by weight with respect to the pulp weight.

In the present invention, calcium carbonate is preferable as the filler, and the ash content in the paper is preferably 10% by weight or more, more preferably 15% by weight or more and 30% by weight or less. When the ash content in the paper is 10% by weight or less, the existing sizing agent having a relatively low molecular weight is adsorbed by the filler having a large specific surface area, and it becomes difficult to secure the size property. However, the sizing agent of the present invention can exert a size effect.
(Other additives)
The pulp slurry can be used in combination with a known internal sizing agent such as neutral rosin, AKD, ASA or the like within a range not impairing the effects of the present invention.

In addition, various nonionic and cationic retention agents, freeness improvers, bulking agents and the like, which are conventionally used, are appropriately selected and used as required.
In addition, an internal additive for papermaking may be added. For example, it may be easily added to basic aluminum compounds such as sulfate band, aluminum chloride, sodium aluminate, basic aluminum chloride, basic polyaluminum hydroxide, and water. Examples thereof include water-soluble aluminum compounds such as decomposable alumina sol, polyvalent metal compounds such as ferrous sulfate and ferric sulfate, and silica sol.

In addition, various starches as paper making aids, polyacrylamide, urea resin, melamine resin, epoxy resin, polyamide resin, polyamide, polyamine resin, polyamine, polyethyleneimine, plant gum, polyvinyl alcohol, latex, polyethylene oxide, hydrophilic cross-linking Various compounds such as polymer particle dispersion and derivatives or modified products thereof can be used.
Furthermore, internal additives for papermaking such as dyes, fluorescent brighteners, pH adjusters, antifoaming agents, pitch control agents, slime control agents and the like can be appropriately added depending on the intended use.
What is necessary is just to set the addition amount of these additives suitably according to desired performance.
The electrophotographic transfer paper of the present invention is particularly preferably a neutral paper obtained by neutral papermaking because the effects of the present invention can be exhibited significantly.

(Paper machine)
The type of the paper machine is not particularly limited, and can be appropriately made with a long paper machine, a twin wire machine, a Yankee paper machine, or the like. The press line pressure is used within the normal operating range. In order to improve the quality of the electrophotographic transfer paper, it is preferable to apply a surface treatment agent. You don't have to. When applying the surface treatment agent, there is no particular limitation on the components of the surface treatment agent, and there is no limitation on the size press type, and a liquid film such as a 2-roll size press, a gate roll size press, or a rod metalling size press. A transfer size press or the like can be used as appropriate.

(surface treatment)
The surface treatment agent is not particularly limited, for example, as raw paper strength agent, raw starch, oxidized starch, esterified starch, cationized starch, enzyme-modified starch, aldehyde-modified starch, modified starch such as hydroxyethylated starch, Cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose, methylcellulose, modified alcohols such as polyvinyl alcohol and carboxyl-modified polyvinyl alcohol, styrene butadiene copolymer, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride Polyacrylic acid ester, polyacrylamide, etc. can be used alone or in combination.

In addition to the above-mentioned agents, surface sizing agents such as styrene acrylic acid, styrene maleic acid, olefinic compounds, and cationic sizing agents can be applied to the surface treatment agent. If the size property is improved, the pen writing sizing degree, which is often required for electrophotographic transfer paper, can be increased. Furthermore, in order to control the electrical resistance and improve the toner fixing property, an inorganic conductive agent such as sodium chloride, sodium sulfate or potassium chloride or an organic conductive agent such as dimethylaminoethyl methacrylate is added and applied externally. It is preferable to do. The coating amount of the surface treatment agent including the conductive agent is appropriately adjusted, but the coating amount is usually about 0.5 to 4.0 g / m ^{2 on} both sides. Moreover, as an application quantity of a electrically conductive agent, it is about 0.02-0.5 g / m < ² > in both surfaces. The present invention is an electrophotographic transfer paper, which is used for PPC paper, laser printer paper, and the like, and is also suitable as an electrophotographic transfer paper and a co-paper having ink jet recording suitability.

  Hereinafter, the present invention will be described with reference to examples relating to electrophotographic transfer paper, but the present invention is not limited thereto. In the examples, “parts” and “%” respectively represent “parts by weight” and “% by weight” unless otherwise specified. In addition, the chemical addition rate indicates the solid content addition rate unless otherwise specified. When it is designated as solid, it indicates the addition rate of the chemical itself, not the solid content. For example, when 0.2% of a 1% chemical is added as a solid content, 20% is added in solid form.

<Measurement and evaluation method>
-Ash content in paper: measured in accordance with JIS P 8251 and ISO 1762.
-Steffith sizing degree: Measured according to JIS P 8122.
Coefficient of friction: measured according to ISO 15359.
-Evaluation of dirt on paper machine: Visual evaluation was performed and determined as follows.
○: There is no problem in operability. △: Some stains are seen, but operation is possible. ×: Dirt is seen and operation is difficult. Electrophotography suitability: 55 sheets / minute of A4 paper with Fuji Xerox copier (Vivace 555). 1000 sheets were printed at a speed and determined as follows.
○: Double feed, jam trouble, paper misalignment after printing is suppressed, transportability is good, and toner fixability is good. ×: Any of double feed, jam trouble, paper misalignment after printing cannot be suppressed. , Poor transportability or poor toner fixability

Inkjet printing suitability evaluation: Printing was performed using a Canon inkjet recording apparatus (iP4100), and visual evaluation of feathering was performed, and was determined as follows.
◎: Very good with no feathering ○: Very little feathering △: Slightly inferior ×: Inferior

<Synthesis examples of cationic and amphoteric copolymers>
(1) Synthesis example 1
In a 0.5 liter four-necked flask equipped with a thermometer, stirrer, reflux condenser and nitrogen inlet tube, 30 parts of isopropanol, 50 parts of styrene, 20 parts of methyl methacrylate, 10 parts of butyl acrylate, dimethylaminoethyl methacrylate 20 And 1.5 parts of n-dodecyl mercaptan were added and heated with stirring to raise the temperature to 85 ° C.

Next, while maintaining the temperature at 85 to 90 ° C., a polymerization initiator solution consisting of 1.5 parts of t-butyl peroxyethyl hexanate and 3 parts of isopropanol was dropped in 3 hours, and aged for 1 hour. Was completed.
Thereafter, while maintaining the temperature at 80 ° C., 8.5 parts of 90% acetic acid for neutralizing the cationic copolymer and 260 parts of warm water were added over 30 minutes and maintained for 1 hour, and 9.5 parts of epichlorohydrin was added. Then, it was kept at 80 ° C. for 2 hours to completely dissolve it.
After cooling, water was added to obtain a cationic copolymer aqueous solution having a solid content of 20%. In addition, when the anion equivalent of the anionic monomer in the monomer component is expressed as a ratio (percentage) with respect to the cation equivalent of the cationic monomer, the cationic content of the copolymer in the obtained internal sizing agent is 24%. The quaternization ratio of the group is 80 mol%, and the weight average molecular weight is 26 × 10 ⁴ .

(2) Synthesis example 2
In a 0.5 liter four-necked flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen introduction tube, 25 parts of isopropanol and 7.6 parts of 90% acetic acid were placed and heated to 80 ° C. with stirring. .
Next, 1.5 parts of n-dodecyl mercaptan and 1 part of azobisisobutyronitrile were dissolved in a monomer mixture of 30 parts of styrene, 50 parts of iso-butyl methacrylate, 1 part of maleic anhydride and 19 parts of dimethylaminoethyl methacrylate. The entire amount of the mixed solution was dropped in 3 hours while maintaining the temperature inside the flask at 80 to 85 ° C., and aged for 1 hour to complete the reaction.
Thereafter, the temperature was kept at 80 ° C., 300 parts of warm water was added and kept for 1 hour, 9 parts of epichlorohydrin was added and kept at 80 ° C. for 2 hours, and completely water-solubilized.
After cooling, water was added to obtain an amphoteric copolymer aqueous solution having a solid content of 20%.
In addition, when the anion equivalent of the anionic monomer in the monomer component is expressed as a ratio (percentage) to the cation equivalent of the cationic monomer, it is 34%, and the copolymer in the obtained internally added sizing agent has its cationic property. The quaternization ratio of the group is 80 mol%, and the weight average molecular weight is 35 × 10 ⁴ .

<Manufacture of electrophotographic transfer paper>
[Example 1]
The aqueous cationic copolymer solution obtained in Synthesis Example 1 was added to light calcium carbonate (“TP-121” manufactured by Okutama Kogyo Co., Ltd.) so that the solid content of the filler was 1.25%. did.
For raw pulp (LBKP 100%) with freeness adjusted to 420 mL, 0.5% liquid sulfuric acid band with respect to pulp solids, cation-modified starch with 0.5% pulp solids, and pulp solids A stock material was prepared by sequentially adding a 0.2% solid fluorescent dye and a yield improver with a solid content of 100 ppm to pulp. This stock was made using an on-top type twin wire paper machine at a paper making speed of 1200 m / min to obtain a printing paper (basis weight 64 g / m ² , ash content in paper 10%). Then, on-machine rod metering size press, 0.05g / m ² of sodium chloride (conductive agent) and 1.5g / m ^{2 of} starch (surface paper strength agent) are coated and dried on both sides, and electrophotographic A transfer paper was obtained. The basis weight at this time was 64 g / m ² and the ash content in the paper was 10%. The Steecht sizing, static and dynamic friction coefficients were measured to evaluate paper machine stains, transportability, toner fixability, and ink jet printability. The measurement and evaluation results are shown in Table 1.

[Example 2]
In Example 1, the cationic copolymer aqueous solution obtained in Synthesis Example 1 was added to light calcium carbonate (“TP-121” manufactured by Okutama Kogyo Co., Ltd.) so that the solid content of the filler was 0.74%. The same procedure as in Example 1 was performed except that an electrophotographic transfer paper having an ash content of 18% was obtained as a papermaking additive.
[Example 3]
In Example 1, the cationic copolymer aqueous solution obtained in Synthesis Example 1 was added to light calcium carbonate (“TP-121” manufactured by Okutama Kogyo Co., Ltd.) so that the solid content of the filler was 0.50%. The same procedure as in Example 1 was performed except that an electrophotographic transfer paper having an ash content of 10% was obtained as a papermaking additive.

[Example 4]
In Example 1, the cationic copolymer aqueous solution obtained in Synthesis Example 1 was added to light calcium carbonate (“TP-121” manufactured by Okutama Kogyo Co., Ltd.) so that the solid content of the filler was 0.30%. The same procedure as in Example 1 was performed except that an electrophotographic transfer paper having an ash content of 18% was obtained as a papermaking additive.
[Example 5]
In Example 1, the cationic copolymer aqueous solution obtained in Synthesis Example 1 was added to light calcium carbonate (“TP-121” manufactured by Okutama Kogyo Co., Ltd.) so that the solid content of the filler was 2.50%. The same procedure as in Example 1 was performed except that an electrophotographic transfer paper having an ash content of 10% was obtained as a papermaking additive.
[Example 6]
In Example 1, the cationic copolymer aqueous solution obtained in Synthesis Example 1 was added to light calcium carbonate (“TP-121” manufactured by Okutama Kogyo Co., Ltd.) so that the solid content of the filler was 1.48%. The same procedure as in Example 1 was performed except that an electrophotographic transfer paper having an ash content of 18% was obtained as a papermaking additive.
[Example 7]
In Example 1, the amphoteric copolymer aqueous solution obtained in Synthesis Example 2 was added to light calcium carbonate (“TP-121” manufactured by Okutama Kogyo Co., Ltd.) so as to have a solid content of filler of 1.25%. The same procedure as in Example 1 was conducted except that an electrophotographic transfer paper having an ash content of 10% was obtained as an additive for use.
[Example 8]
In Example 1, the amphoteric copolymer aqueous solution obtained in Synthesis Example 2 was added to light calcium carbonate (“TP-121” manufactured by Okutama Kogyo Co., Ltd.) so that the solid content of the filler was 0.74%. The same procedure as in Example 1 was conducted except that an electrophotographic transfer paper having an ash content of 18% was obtained.

[Comparative Example 1]
In Example 1, instead of the cationic copolymer aqueous solution obtained in Synthesis Example 1, a neutral rosin-based sizing agent was added at 0.6% solid content to pulp, and calcium carbonate ("Okutama Kogyo" TP-121 ") was added at a solid content of 13% by weight to the pulp to obtain an electrophotographic transfer paper having an ash content of 10%. The results are shown in Table 2.
[Comparative Example 2]
Calcium carbonate ("TP-121" manufactured by Okutama Kogyo Co., Ltd.) was added in an amount of 23% by solid weight to pulp to obtain an electrophotographic transfer paper having an ash content of 18%.

[Comparative Example 3]
The same procedure as in Comparative Example 1 was carried out except that an alkyl ketene dimer sizing agent was added in place of the neutral rosin sizing agent and 0.15% solid content of pulp was added to obtain an electrophotographic transfer paper.
[Comparative Example 4]
The same procedure as in Comparative Example 2 was carried out except that an alkyl ketene dimer sizing agent was added instead of the neutral rosin sizing agent in an amount of 0.15% to pulp solids.
[Comparative Example 5]
The same procedure as in Comparative Example 1 was conducted except that an alkenyl succinic anhydride sizing agent was added instead of the neutral rosin sizing agent in an amount of 0.2% solids content to pulp.
[Comparative Example 6]
The same procedure as in Comparative Example 2 was conducted except that an alkenyl succinic anhydride sizing agent was added instead of the neutral rosin sizing agent in an amount of 0.2% solids to pulp.

The results shown in Table 1 indicate the following.
1) Measurement results of the steecht sizing degree, static and dynamic friction coefficients of Examples 1 to 8 and Comparative Examples 1 to 6, and paper machine stains, electrophotographic suitability (transportability, toner fixability) and ink jet print suitability Comparing the evaluation results, Examples 1 to 8 have no reduction in size, static and dynamic friction coefficients, and excellent evaluation of paper machine contamination, electrophotographic suitability (conveyability, toner fixability), and ink jet printing suitability. It shows that.
2) For example, with respect to the degree of steecht, the degree of steecht of Comparative Examples 1, 2, 4, and 6 is 27 seconds or less, whereas that of all Examples 1 to 8 is 30 seconds or more. Examples 1 to 8 show excellent sizing properties.
3) Regarding the static and dynamic friction coefficients, the static friction coefficients of Comparative Examples 3 and 4 are 0.53 and 0.54, whereas those of Examples 1 to 8 are in the range of 0.65 to 0.70. Since the dynamic friction coefficients of Comparative Examples 3 and 4 are 0.46, while those of Examples 1 to 8 are in the range of 0.49 to 0.51, Examples 1 to 8 are There is little decrease and shows that it is excellent.

4) Regarding dirt on the paper machine, Comparative Examples 3 to 6 have problems in operability, whereas those in Examples 1 to 8 have no problems and show that they are excellent.
5) Regarding the electrophotographic aptitude, Comparative Examples 3 and 4 have a problem in transportability, whereas those in Examples 1 to 8 have no problem and are excellent.
6) Regarding the ink jet printing suitability, Comparative Examples 1, 2, 4 and 6 have problems in ink jet printing suitability, whereas those in Examples 1 to 8 show no problems and are excellent.

  From the measurement and evaluation results of Examples 1 to 8 and Comparative Examples 1 to 6 described above, the electrophotographic transfer paper of the present invention contains a papermaking additive containing a specific copolymer even if it has a high ash content. Therefore, since the surface treatment agent contains a conductive agent, it has less friction and dirt on the paper machine, has an appropriate size, and has an electrophotographic aptitude with good toner fixing property and transportability. Since the electrophotographic transfer paper having ink jet printing suitability is obtained, it is clear that the above-described problems of the present invention have been achieved.

Claims (4)

An electrophotographic transfer paper containing a paper additive, which is a mixture of a copolymer and a filler, on a base paper, and a surface treatment agent applied and dried on the base paper,
The copolymer is a copolymer having a quaternization rate of 40 mol% or more obtained by polymerizing a monomer component containing at least a hydrophobic monomer (A) and a cationic monomer (B), and the surface treatment agent is An electrophotographic transfer paper comprising a conductive agent.   2. The electrophotographic transfer paper according to claim 1, wherein the copolymer is a cationic copolymer or an amphoteric copolymer containing an anionic monomer (C).   The amphoteric copolymer is obtained by polymerizing a monomer component in which the ratio of the anionic equivalent derived from the anionic monomer (C) to the cationic equivalent derived from the cationic monomer (B) is 0.1 to 90%. The electrophotographic transfer paper according to claim 1 or 2, characterized in that:   4. The electrophotographic transfer paper according to claim 1, wherein the filler contains 10 to 30% by weight of calcium carbonate as ash in the paper.