JP2008049688A - Resin for coating paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin for coating paper which has light resistance and water resistance in a printing portion equivalent to a conventional coating composition and wherein the white paper portion of the recording paper is not yellowed during long time storage, and a coating composition and a recording paper coated with the coating composition. <P>SOLUTION: The coating composition containing the resin for coating paper containing a copolymer of (A) a (meth)acrylamide, (B) a salt of diarylamine and (C) a salt of polymerizable amine composition (excluding a diarylamine derivative) or a quaternary ammonium salt is coated on an original paper to obtain a recording paper which has the light resistance and water resistance in a printing portion equivalent to the properties attained when a conventional coating composition is used and is remarkably improved in the yellowing resistance in the white paper portion during long time storage. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a paper coating resin used for recording with water-based ink. More specifically, the present invention relates to a resin for paper coating that has light resistance and water resistance equivalent to those of conventional coating compositions and is excellent in the effect of preventing yellowing of a white paper portion under long-term storage of recording paper.

  Inkjet printers have rapidly spread due to their ease of use because they can perform high-speed printing and multicolor printing without any development or fixing operations. In addition, with the widespread use of digital cameras, the opportunity to print data taken with an inkjet printer as an alternative to photography is increasing. For this reason, recording paper used for such applications is required not only to have high printing portion light resistance and water resistance, but also to prevent yellowing of the white paper portion even after long-term storage. As a method for obtaining a recording paper with improved light resistance and water resistance of the printing portion, for example, a method of containing a hydrochloride of a copolymer of diallylamine and (meth) acrylamide in the recording paper (Patent Document 1) is known. However, this method does not solve the problem that the white paper portion yellows when the recording paper is stored for a long period of time, and has high light resistance and water resistance of the printing portion and yellowing of the white paper portion under long-term storage. It has been desired to develop a paper coating resin having an excellent prevention effect.

In response to these demands, the present inventors have previously described a resin for paper coating containing a copolymer of (meth) acrylamide and a specific amine compound (Patent Document 2, Patent Document 3). ) Was proposed.

JP-A 64-77572

Japanese Patent Application No. 2006-193728

Japanese Patent Application No. 2006-198817

An object of the present invention is to provide a paper coating that has the same light resistance and water resistance as the conventional coating composition, and that the blank portion of the recording paper does not turn yellow even if the recording paper is stored for a long period of time. It is to provide a working resin, a coating composition, and a recording paper coated with the coating composition.

  As a result of intensive studies on paper coating resins containing various copolymers of (meth) acrylamide and amine compounds in order to solve the above problems, the present inventor has (A) (meth) acrylamide and ( B) A coating composition comprising a paper coating resin containing a salt of diallylamine and a copolymer of (C) a polymerizable amine compound (excluding diallylamine derivatives) or a quaternary ammonium salt is applied to the base paper. In the same manner as that proposed by the present inventors in Japanese Patent Application No. 2006-193728 and Japanese Patent Application No. 2006-198817, the printed portion has the same light resistance as that obtained when a conventional coating composition is used. The present invention was completed by finding that a recording paper having water resistance and a markedly improved effect of preventing yellowing of the white paper portion during long-term storage can be obtained.

Hereinafter, the present invention will be described in detail.
In the paper coating resin in the present invention, (B) diallylamine salt includes diallylamine hydrochloride, diallylamine sulfate, diallylamine phosphate, diallylamine inorganic acid salt, diallylamine acetate, diallylamine methanesulfonate, etc. And diallylamine hydrochloride, diallylamine sulfate and diallylamine methanesulfonate are preferred.

In the paper coating resin of the present invention, (C) a polymerizable amine compound (excluding diallylamine derivatives) or a quaternary ammonium salt includes vinylamine, di (meth) acryloyloxy (methyl) amine, 3- Salts of primary amine compounds such as amino-3-methyl-1-butyne, methylaminoethyl (meth) acrylate, ethylaminoethyl (meth) acrylate, propylaminoethyl (meth) acrylate, iso-propylaminoethyl (meth) Salts of secondary amine compounds such as acrylate, butylaminoethyl (meth) acrylate, tert-butylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminoethyl (meth) acrylate , Diethyl Salts of tertiary amine compounds such as aminopropyl (meth) acrylate, vinylbenzyldimethylamine, (meth) acryloyloxyalkylpyridine, N, N-dimethylaminopropyl (meth) acrylamide, vinylpyridine, dimethylaminoethyl (meth) acrylate Methyl chloride quaternized salt, dimethylaminopropyl (meth) acrylate methyl chloride quaternized salt, diethylaminoethyl (meth) acrylate methyl chloride quaternized salt, diethylaminopropyl (meth) acrylate methyl chloride quaternized salt And quaternary ammonium salts such as methyl chloride quaternized salt of vinylbenzyldimethylamine and methyl chloride quaternized salt of N, N-dimethylaminopropyl (meth) acrylamide. Salt or quaternary ammoni Beam salts are preferred, methyl chloride dimethylaminoethylmethacrylate 4 Kyukashio, and methyl chloride 4 Kyukashio vinylbenzyl dimethylamine are more preferable. In the present invention, the “polymerizable diallylamine derivative not included in the polymerizable amine compound (B)” refers to a compound in which the nitrogen atom of diallylamine is substituted with an alkyl group, a cycloalkyl group, a benzyl group, or the like. Quaternary ammonium salts such as diallylmethylamine, diallylethylamine, diallyl-n-propylamine, diallyl-iso-propylamine, diallyl-n-butylamine, diallyl-tert-butylamine, diallylbenzylamine, diallylcyclohexylamine and The quaternary ammonium salt etc. are mentioned.

  The proportion of (A) (meth) acrylamide in the monomer unit constituting the paper coating resin in the present invention is not particularly limited, but is usually in the range of 30 to 99 mol%, preferably 50 to 90 mol%. The total of (B) diallylamine salt and (C) polymerizable amine compound (excluding diallylamine derivatives) or quaternary ammonium salt is not particularly limited, but is preferably in the range of 1 to 70 mol%. Is from 10 to 50 mol%. Although the ratio of (B) and (C) is not particularly limited, the ratio of (B) and (C) is usually 1 to 99 mol when the total of (B) and (C) is 100 mol%. %, Preferably the ratio of (B) is 1-50 mol%, the ratio of (C) is 50-99 mol%, more preferably the ratio of (B) is 5-30 mol%, (C) Is 70 to 95 mol%.

  The method for synthesizing the resin for paper coating in the present invention may be any known water-soluble polymer polymerization method, and is not particularly limited. However, radical polymerization is preferred, and the polymerization solution is usually used in the presence of a radical polymerization initiator. Polymerization is carried out by maintaining the temperature within a predetermined range. As the polymerization method, either batch polymerization in which all monomers are charged in a reaction vessel in a batch and polymerization, or semi-batch polymerization method in which a part of the monomer monomer is continuously added during polymerization may be used. Legal is preferred. It is not necessary to maintain the same temperature during the polymerization, and the temperature may be appropriately changed as the polymerization progresses, and is performed while heating or removing heat as necessary. The polymerization temperature varies depending on the type of monomer used and the type of polymerization initiator, and is generally in the range of 10 to 100 ° C. in the case of a single initiator, and lower in the case of a redox polymerization initiator. When the polymerization is carried out, it is generally from -5 to + 50 ° C, and when added successively, the temperature is generally from 30 to 90 ° C. The polymerization time is not particularly limited, but is generally 1 to 40 hours. Preferably, the polymerization is carried out with a single initiator at a temperature of 40 to 90 ° C. for about 1 to 20 hours. The atmosphere in the polymerization vessel is not particularly limited, but generally it is preferably carried out in an atmosphere of an inert gas such as nitrogen gas.

  As the polymerization solvent, water is usually used, but it may be a mixture of other water-soluble solvents such as methanol, ethanol, isopropanol, acetone, ethylene glycol and water. Of course, a polymerization initiator and a chain transfer agent described later can be present in the aqueous solvent.

  In the semi-batch polymerization method, the addition rate of each monomer may be the same or different, but it is preferable that diallylamine hydrochloride and amine compound are faster than acrylamide. Moreover, although the addition start time of each monomer may be simultaneous or different, it is preferable to start addition before the addition of another monomer is complete | finished.

  As a polymerization initiator used as needed when synthesizing a (meth) acrylamide polymer, a general water-soluble initiator can be used. Specifically, persulfates such as ammonium persulfate, potassium persulfate and sodium persulfate, peroxides such as hydrogen peroxide, benzoyl peroxide, di-t-butyl peroxide, 2,2′-azobis-2 -Methylpropionamidine hydrochloride, 2,2'-azobis-2,4-dimethylvaleronitrile, 2,2'-azobis-N, N'-dimethyleneisobutylamidine hydrochloride, 2,2'-azobis-2- Methyl-N- (2-hydroxyethyl) -propionamide, 2,2′-azobis-2- (2-imidazolin-2-yl) -propane and its salts, 4,4′-azobis-4-cyanovaleric acid And azo compounds such as salts thereof. In this case, it can be used alone, but it can also be used as a redox-type initiator by combining a reducing substance such as sulfite, amines, and the like. Examples of the reducing agent in this case include sulfites, bisulfites, organic amines such as N, N, N ′, N′-tetramethylethylenediamine, and reducing sugars such as aldose and ketose. It is also possible to use two kinds of the above polymerization initiators in combination. The addition amount of the polymerization initiator is usually 0.00001 to 10.0% by weight, preferably 0.5 to 20% by weight, based on the monomer. In the case of a redox system, the addition amount of the reducing agent with respect to the polymerization initiator is 0.1 to 100%, preferably 0.2 to 80% on a molar basis.

  The polymerization initiator used as needed during the synthesis may be added in advance to the aqueous solvent to which the monomer is to be added, or may be continuously added to the reaction system simultaneously with each monomer. However, it is preferably added in advance to the aqueous solvent.

  Although there is no restriction | limiting in particular in the chain transfer agent used as needed when synthesize | combining, A water-soluble chain transfer agent is preferable. Specific examples of the initiator include hypophosphites such as hypophosphorous acid and sodium hypophosphite, alkali metal salts such as allyl sulfonic acid, methacryl sulfonic acid and sodium salts or potassium salts thereof, or ammonium salts. And allyl compounds such as allylamine and allyl alcohol, mercaptans such as mercaptoethanol, mercaptopropionic acid and thioglycolic acid, and cysteamine.

Moreover, pH adjustment is performed as needed after completion | finish of a synthesis reaction. For pH adjustment, alkali metal hydroxide, alkali metal bicarbonate, alkali metal carbonate, ammonia, hydrochloric acid, sulfuric acid and the like are used, among which sodium hydroxide, potassium hydroxide, hydrochloric acid and sulfuric acid are preferable.

  In the resin for paper coating in the present invention, various compounds are added to the polymer obtained by the above-described synthesis method as long as the original properties such as improvement of blank yellowing, light resistance and water resistance are not impaired. I can do it.

The coating composition of the present invention consists of a paper coating resin, a pigment, and an aqueous binder obtained as described above.
In preparing the coating composition of the present invention, the composition ratio of the pigment and the aqueous binder is determined according to the use and purpose, and is not particularly different from the composition generally employed in the industry. The preferable composition ratio of both is 1 to 200 parts by weight, more preferably 5 to 50 parts by weight of the aqueous binder with respect to 100 parts by weight of the filler. The solid content of the paper coating resin is preferably 0.05 to 50 parts by weight, more preferably 0.1 to 30 parts by weight, per 100 parts by weight of the filler.

The pigment that is a component of the coating composition of the present invention may be those conventionally used for paper coating, for example, fine silicic acid, clay, talc, calcium carbonate (heavy or light), Examples thereof include aluminum hydroxide, satin white, titanium oxide, barium sulfate, and aluminum silicate. These pigments can be used alone or in admixture of two or more.

  The aqueous binder may be one that has been conventionally used for paper coating, and a water-soluble binder or a water-emulsifying binder can be used. Examples of the water-soluble binder include unmodified or modified starches such as oxidized starch and phosphate esterified starch, water-soluble proteins such as polyvinyl alcohol, casein and gelatin, and carboxymethyl cellulose. And modified celluloses. Examples of the water-emulsifying binder include carboxyl group-containing styrene-butadiene resins, styrene-vinyl acetate resins, ethylene-vinyl acetate resins, and methyl methacrylate resins. These aqueous binders can be used alone or in admixture of two or more.

  In addition to the paper coating resin (I), the coating composition of the present invention may contain other water-resistant agents and resin components such as a printability improving agent as required. Furthermore, as other components, for example, dispersants, viscosity / fluidity modifiers, antifoaming agents, preservatives, lubricants, water retention agents, and coloring agents such as dyes and colored pigments, as necessary. Can be blended.

The coating composition of the present invention is applied to paper by a conventionally known method such as a blade coater, an air knife coater, a bar coater, a size press coater, a gate roll coater, or a cast coater. Is done. Thereafter, the recording paper of the present invention can be produced by performing necessary drying and further performing a smoothing treatment with a super calender or the like as necessary.

By using the coating composition containing the paper coating resin (I) of the present invention, the white paper yellowing improvement effect is superior without impairing the light resistance and water resistance of the printed part as compared with the conventional coating composition. Can be obtained.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these. In the examples, “%” and “part” representing the content or amount used are based on weight unless otherwise specified.
The pH is a value obtained by measuring the pH of a sample immediately after preparation at 25 ° C. using a glass electrode type hydrogen ion concentration meter [manufactured by Toa Denpa Kogyo Co., Ltd.].
The viscosity is a value obtained by measuring the viscosity of the sample immediately after adjustment at No. 1 rotor 12 rpm and 25 ° C. using a B-type viscosity system [manufactured by Tokyo Keiki Co., Ltd., BL type].

(Synthesis Example 1)
<Synthesis of diallylamine hydrochloride (B1)>
A four-necked flask equipped with a thermometer and a reflux condenser was charged with 981.0 g of ion-exchanged water, and deaerated and purged with nitrogen in the reaction vessel by flowing nitrogen at a flow rate of 200 ml per minute for 1 hour. Nitrogen was kept flowing during the synthesis. After charging 534.5 g (5.4 mol) of 36% hydrochloric acid, 520 g (5.4 mol) of diallylamine (manufactured by Guangei Chemical Co., Ltd.) was added dropwise over 3 hours. After adjusting the pH to 2.5 with 36% hydrochloric acid, 0.4 g of ion-exchanged water was added to obtain diallylamine hydrochloride (B1) having a monomer component of 35%.

(Synthesis Example 2)
<Synthesis of dimethylaminoethyl methacrylate hydrochloride (C1)>
A four-necked flask equipped with a thermometer and a reflux condenser was charged with 749.5 g of ion-exchanged water, and deaerated and purged with nitrogen in the reaction vessel by flowing nitrogen at a flow rate of 200 ml per minute for 1 hour. Nitrogen was kept flowing during the synthesis. After charging 258.4 g (2.54 mol) of 36% hydrochloric acid, 400 g (2.54 mol) of dimethylaminoethyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise over 3 hours. After adjusting the pH to 2.5 with 36% hydrochloric acid, 0.3 g of ion-exchanged water was added to obtain dimethylaminoethyl methacrylate hydrochloride (C1) having a monomer component of 35%.

<Synthesis of resin for paper coating>
A four-necked flask equipped with a thermometer and a reflux condenser was charged with 67.1 g of ion-exchanged water, and the temperature was raised to 70 ° C., and nitrogen was allowed to flow for 30 minutes at a flow rate of 300 ml / min. Went. Nitrogen was kept flowing during the synthesis. At 70 ° C., 0.78 g of ammonium persulfate was added. Thereto, 75.4 g (0.54 mol) of a 50% aqueous acrylamide solution was added dropwise over 5 hours while maintaining the temperature in the system at 70 ° C. Simultaneously with the start of dropping, sodium hypophosphite was added to a mixed solution of (B) diallylamine hydrochloride 29.3 g (0.08 mol) and (C) dimethylaminoethyl methacrylate hydrochloride 83.0 g (0.15 mol). Addition of 0.099 g and disodium ethylenediaminetetraacetic acid dihydrogen disodium dihydrate 0.012 g was started, and the addition was continued while maintaining the temperature in the system at 70 ° C. After 3 hours, the addition was completed. After completion of the dropwise addition, the temperature in the system was kept at 70 ° C for 4 hours, and then the temperature in the system was lowered to 30 ° C or lower. After adjusting the pH to 5.2 with sodium hydroxide, 1.4 g of ion-exchanged water is added, the polymer component is 30%, the non-volatile content is 32.0%, the B-type viscosity at 25 ° C. is 1313 mPa · s, and the pH is 5. No. 3 paper coating resin S1 was obtained.

(Examples 2 to 8)
<Synthesis of resin for paper coating>
(A) (meth) acrylamide, (B) salt of diallylamine, (C) salt of polymerizable amine compound (excluding diallylamine derivatives) or quaternary ammonium salt, ammonium persulfate, sodium hypophosphite, ethylenediaminetetraacetic acid diacetate Except for changing the amounts of disodium hydrogen dihydrate and ion-exchanged water as shown in Tables 1 and 2, the same operation as in Example 1 was performed to obtain paper coating resins S2 to S8.
Tables 1 and 2 show the properties, nonvolatile content (%), viscosity (20 ° C.) and pH of the paper coating resins S1 to S8 obtained in Examples 1 to 8 above.

Example 9
<Production example of coating composition>
Mizukasil P-78D (pigment, ultrafine silica produced by Mizusawa Chemical Co., Ltd.) 100 parts by weight, polyacrylic acid pigment dispersant 0.2 parts by weight, polybilinyl alcohol (aqueous binder) 20 parts by weight, water Was added to prepare a master color so that the solid content was 16.0%. Subsequently, the solid content of the paper coating resin (S1) described in the above example was added to 100 parts by weight of the master color pigment at a ratio of 20 parts by weight, and the solid content was adjusted to 15.5%. A coating composition T1 having a pH of 4.8 and a viscosity of 140 mPa · s was obtained.

(Examples 10 to 16)
A coating composition T2 to T8 was obtained in the same manner as in Example 9 except that the paper coating resin S1 in Example 9 was changed to the paper coating resin shown in Table 4.
Tables 3 and 4 show the measurement results of physical properties such as pH and viscosity of coating compositions T1 to T8.

(Comparative Example 1)
A coating composition T9 was obtained in the same manner as in Example 7 except that the resin S1 for paper coating was not blended in Example 9 and 40 parts by weight of polybilinyl alcohol (aqueous binder) was added. . Table 5 shows the measurement results of physical properties such as pH and viscosity of the coating composition T9.

(Comparative Example 2 and Comparative Example 3)
Instead of blending the paper coating resin S1 in Example 9, Srz. 1001 (manufactured by Sumitomo Chemical Co., Ltd .: copolymer of acrylamide and diallylamine hydrochloride) or Jetfix 70 (produced by Satorita Chemical Co., Ltd .: dimethylamine / epichlorohydrin resin) is blended in the same manner as in Example 7. It prepared and obtained coating composition T10 and T11. Table 5 shows the measurement results of physical properties such as pH and viscosity of the coating compositions T10 and T11.

<Examples of recording paper production and test methods>
About coating composition T1-T11, it apply | coated so that the coating amount might be set to 15 g / m < ² > using the wire rod on the single side | surface of the fine paper of rice basic weight 120g / m < ² >. Immediately after the coating, it was dried with hot air at 120 ° C. for 60 seconds, and further subjected to a super calender treatment once under the conditions of a temperature of 60 ° C. and a linear pressure of 30 kN / m to obtain a recording paper. The recording paper thus obtained was subjected to a water resistance test, a light resistance test, and a white paper yellowing resistance test, and the test results are shown in Tables 3 to 5. The measurement method is as follows.

<Water resistance>
A 0.02 cc water droplet is dropped on the recording paper on the ink jet printing portion and left to stand. Visually determine the degree of bleeding
Water resistance (poor) 1-5 (excellent)

<Light resistance>
The ink jet print portion is irradiated with light for 80 hours using a fade meter (carbon arc) and the print density before irradiation is measured and compared using a Macbeth densitometer.
Light resistance (poor) 1-5 (excellent)

<White paper yellowing resistance>
After heating a blank paper portion not subjected to inkjet printing for 3 days under wet heat conditions (water desiccator 100% / RH method (80 ° C.)), I measurement (using Color Touch 2)
White paper yellowing resistance (poor) 1 to 5 (excellent)

Ｃ１：ジメチルアミノエチルメタクリレート塩酸塩
ＱＤＡＭ：ジメチルアミノエチルメタクリレートの塩化メチル４級化塩（アルドリッチ社製）

C1: Dimethylaminoethyl methacrylate hydrochloride QDAM: Methyl chloride quaternized salt of dimethylaminoethyl methacrylate (Aldrich)

ＱＶＢＤＡ：ビニルベンジルジメチルアミンの塩化メチル４級化塩（アルドリッチ社製）

QVBDA: Methyl chloride quaternized salt of vinylbenzyldimethylamine (Aldrich)

Claims (5)

  (A) A resin for paper coating characterized by a copolymer of (meth) acrylamide and (B) a salt of diallylamine and (C) a salt of a polymerizable amine compound (excluding diallylamine derivatives) or a quaternary ammonium salt .   The resin for paper coating according to claim 1, wherein (C) is a salt of dimethylaminoethyl methacrylate or a quaternary ammonium salt. (A) (meth) acrylamide is 30 to 99 mol%, (B) diallylamine salt and (C) polymerizable amine compound (excluding diallylamine derivatives) salt or quaternary ammonium salt is 1 to 70 mol% in total And the ratio of (B) and (C) is 1 to 99 mol% when the total of (B) and (C) is 100 mol%. The resin for paper coating of 1-2. A coating composition comprising the paper coating resin according to claim 1, a pigment, and an aqueous binder. A recording paper obtained by coating the paper with the coating composition according to claim 4.