JP2979600B2 - Coating composition for paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a paper coating composition which provides a coated paper having excellent printability and printing effect.

<Conventional technology> A coated paper obtained by applying a paper coating composition mainly composed of a pigment and an aqueous binder to paper, and performing necessary steps such as drying and calendering, has an excellent printing effect. Due to its features, it is widely used in commercial printed materials, magazines and books, etc., but efforts to improve the quality of coated papers are still being made with the advancement of quality requirements and the speeding up of printing.
Particularly in offset printing, which accounts for the majority of printing, improvements in ink receptivity under the influence of shampoo water, water resistance of wet topics and wet labs, and blister resistance in rotary printing are important issues in the industry. is there.

Conventionally, to solve such problems, a melamine-formaldehyde resin, a urea-formaldehyde resin, or a water-resistant resin such as a polyamide polyurea-formaldehyde resin as disclosed in Japanese Patent Publication Nos. 44-11667 and 59-32597. Attempts have been made to solve the problem by adding an agent or a printability improving agent.

However, these water-proofing agents, printability improvers, etc., have effective properties, but are not always practically satisfactory because of serious drawbacks and insufficient effects.

For example, aminoplast resins such as melamine-formaldehyde resin and urea-formaldehyde resin not only generate a large amount of formaldehyde at the time of work or from coated paper, but also have little effect of improving ink receptivity and blister resistance. In addition, when the pH of the coating composition is increased, there is a problem that a water-resistant effect is remarkably difficult to obtain.

Polyamide polyurea-formaldehyde resin is effective for improving ink receptivity and blister resistance at the same time as imparting water resistance, but the degree of improvement is insufficient for recent demands for advanced coated paper quality. Met. Accordingly, the present inventors have disclosed a further improved paper coating composition in Japanese Patent Application Laid-Open No. 62-125093 and the like. Higher performance is required.

<Problems to be Solved by the Invention> An object of the present invention is to provide a paper coating that imparts high blister resistance, which was not obtained by conventional techniques, to coated paper, in addition to high water resistance and ink acceptability. It is to provide a composition.

The present inventors have found that a composition containing a specific water-soluble resin is effective for such purpose, and have completed the present invention.

<Means for Solving the Problems> That is, the present invention provides a paper coating composition containing the following three components.

Pigment (I), aqueous binder (II), and condensation product (a) of alkylene diamine or polyalkylene polyamine with urea, and further aldehydes (b) or epihalohydrins or α, γ-dihalo-β-hydrin When the water-soluble resin (III) obtained by reacting the compound (c) with the aldehyde (b) is used, the reaction is carried out at pH 7 or lower, or first, at pH 8 to 12. Later, it was performed at pH 7 or lower.

 The contents of the present invention will be described in more detail.

Specific examples of the alkylenediamine or polyalkylenepolyamine used for producing the water-soluble resin (III) used in the present invention include aliphatic diamines such as ethylenediamine and propylenediamine, diethylenetriamine,
Triethylenetetramine, tetraethylenepentamine,
Iminobispropylamine, 3-azahexane-1,6-
Examples thereof include polyalkylene polyamines such as diamine and 4,7-diazadecane-1,10 diamine. Among them, diethylenetriamine and triethylenetetramine are industrially advantageous. These alkylenediamines or polyalkylenepolyamines can be used not only as one kind but also as a mixture of two or more kinds.

Examples of the urea include urea, thiourea, guanylurea, methylurea, dimethylurea, and the like, and urea is preferable from an industrial viewpoint.

As the aldehydes, formaldehyde, alkyl aldehydes such as acetaldehyde and propyl aldehyde, glyoxal, alkyl dialdehydes such as propane dial and butane dial, and the like can be used, but formaldehyde or glyoxal is industrially preferable. Aldehydes can be used not only as one kind but also as a mixture of two or more kinds.

Epihalohydrins have the general formula [Wherein, X represents a halogen atom, w represents 1, 2 or 3]. Preferred examples include epichlorohydrin, epibromohydrin and the like. These can be used not only as one kind but also as a mixture of two or more kinds.

α, γ-Dihalo-β-hydrins are represented by the general formula [Wherein, X and Z each represent a halogen atom, and Y represents a hydroxyl group], for example, 1,3-dichloro-2-propanol and the like.

The water-soluble resin (III) is obtained by adding a condensation reaction product (a) of an alkylene diamine or a polyalkylene polyamine with a urea to an aldehyde (b) or an epihalohydrin or an α, γ-dihalo-β-hydrin ( It is obtained by subjecting C) to a crosslinking reaction.

The condensation reaction of the alkylene diamine or polyalkylene polyamine with the urea is usually performed at 100 to 180 ° C, preferably 110 to 160 ° C, for 1 to 6 hours while removing generated ammonia outside the system. The amount of the urea to be used is preferably 0.5 to 1.0 mol based on 1.0 mol of the primary and secondary amino groups of the alkylene diamine or polyalkylene polyamine. Part of the urea and alkylenediamine or polyalkylene polyamine and 120-180 ° C, preferably 140
After the deammonification reaction at ~ 160 ° C, the remaining urea is added, and the reaction can be further performed in two stages, such as a deammonia reaction at 100-180 ° C, preferably 110-160 ° C.

The condensation reaction product (a) thus obtained is further subjected to a crosslinking reaction with an aldehyde (b) or a crosslinking reaction with an epihalohydrin or an α, γ-dihalo-β-hydrin (c), A water-soluble resin (III) is obtained. Aldehydes (b) and epihalohydrins or α, γ-dihalo-β-hydrins (c) can be used simultaneously.

The reaction of the condensation reaction product (a) with the aldehydes (b) and / or epihalohydrins or α, γ-dihalo-β-hydrins (c) is preferably performed at a concentration of 20 to 80% by weight, more preferably 30 to 80% by weight. It is carried out in a 70% by weight aqueous solution.

When reacting the condensation reaction product (a) with the aldehydes (b), the reaction is finally carried out on the acidic side of pH 7 or less, preferably pH 3-6. Thus, aldehydes (b)
Is reacted on the acidic side, whereby the condensation reaction product (a) can be crosslinked. For example, after adjusting the pH to 7 or less, preferably 3 to 6 in advance with an acid such as hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid, the reaction can be performed at 40 to 80 ° C for 1 to 10 hours. In addition, the reaction is first performed under an alkaline condition of pH 8 to 12, and then the pH is reduced to 7 or less, preferably pH 3 to 12.
It is also preferable to carry out the crosslinking reaction by adjusting the acidity to 6. In this case, the reaction under alkaline conditions is performed at 40 to 80 ° C for 0.5 to 5 hours, and the reaction under acidic conditions is performed at 40 to 80 ° C for 1 to 10 hours.
The amount of the aldehyde (b) to be used is preferably 0.1 to 3 mol, more preferably 0.3 to 1.5 mol, per 1 mol of the condensation reaction product (a). After the completion of the above-mentioned reaction, if necessary, the pH is adjusted to 6 to 10 using caustic soda, caustic potash, or the like, whereby the water-soluble resin (III) used in the present invention is used.
Is obtained.

Condensation reaction product (a) and epihalohydrins or α,
When reacting with γ-dihalo-β-hydrins (c), the reaction is preferably carried out at a temperature of 30 to 90 ° C., preferably 40 to 80 ° C. under a condition of pH 5 or more, more preferably pH 6 to 9. Perform a time reaction. The amount of the epihalohydrins or α, γ-dihalo-β-hydrins (c) used is preferably 0.1 to 3 mol, more preferably 0.3 to 2.0 mol, per 1 mol of the condensation reaction product (a).

The water-soluble resin (III) of the present invention is obtained in the form of an aqueous solution, and preferably has a 60% aqueous solution having a viscosity of 100 to 1 at 25 ° C.
000 cps and a pH of 6-10.

The present invention further provides a pigment (I), an aqueous binder (I)
Also provided is a composition comprising I), a water-soluble resin (III) and a polyalkylene polyamine and / or a reaction product (IV) of a polyalkylene polyamine with a quaternizing agent.

Further, a composition containing a pigment (I), an aqueous binder (II), and a product (V) obtained by further reacting a reaction product of a polyalkylene polyamine and a quaternizing agent with a water-soluble resin (III). Also provide things.

Here, the polyalkylene polyamine is a compound having two primary amino groups and at least one secondary amino group in a molecule, and specifically, for example, diethylene triamine, triethylene tetramine, tetraethylene pentamine, iminobis Examples thereof include propylamine, 3-azahexane-1,6-diamine, and 4,7-diazadecane-1,10-diamine.

As the quaternizing agent, various substances shown below can be used.

A halogen-containing compound represented by the general formula R ₁ -X, wherein R ₁ represents a lower alkyl group, an alkenyl group, a benzyl group or a phenoxyethyl group, and X represents a halogen atom. Preferred examples include methyl chloride, ethyl chloride, propyl chloride, allyl chloride, benzyl chloride, phenoxyethyl chloride, and bromides and iodides corresponding to these chlorides.

Dialkyl sulphite and dialkyl sulphate represented by the general formula (R ₂ O) ₂ SO _{V wherein} R ₂ represents a lower alkyl group and v represents 1 or 2. Preferred examples include dimethyl sulfate, diethyl sulfate, dimethyl sulfate, diethyl sulfate and the like.

General formula [Wherein R ₃ represents a hydrogen atom, a lower alkyl group, a hydroxyalkyl group or a phenyl group]. Preferred examples include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, glycidol and the like.

General formula [In the formula, X represents a halogen atom, w represents 1, 2 or 3.] epihalohydrins represented by the following formula: Preferred examples include epichlorohydrin, epibromohydrin and the like.

Monohalohydrins represented by the general formula HOCH ₂ (CH ₂ ) _W X wherein X and w are the same as described above. Preferred examples include ethylene chlorohydrin, ethylene bromohydrin and the like.

General formula [Wherein, X is the same as above, one of Y and Z represents a halogen atom and the other represents a hydroxyl group]. Preferred examples are 1,3
-Dichloro-2-propanol, 2,3-dichloro-1-
And propanol.

Among the above, particularly preferred quaternizing agents include epichlorohydrin. The compounds used as quaternizing agents as described above can be used alone or in combination of two or more.

Examples of the pigment (I) in the present invention include white inorganic pigments such as kaolin, talc, calcium carbonate (heavy and light), aluminum hydroxide, satin white and titanium oxide, and polystyrene, melamine-formaldehyde resin, and urea-formaldehyde resin. White organic synthetic pigments can be used alone or in combination of two or more. Alternatively, a colored inorganic or organic pigment may be used in combination.

Examples of the aqueous binder (II) in the present invention include water-soluble binders such as oxidized starch, phosphated starch, polyvinyl alcohol, casein, gelatin, carboxymethyl cellulose, styrene-butadiene resin, vinyl acetate resin, ethylene-vinyl acetate. resin,
Water-emulsifying binders such as methyl methacrylate resins can be used alone or in combination of two or more.

The preferred composition ratio of the paper coating composition of the present invention is such that the aqueous binder (II) is 5 parts by weight based on 100 parts by weight of the pigment (I).
The amount is from 200 to 200 parts by weight, more preferably from 10 to 50 parts by weight, and the amount of the water-soluble resin (III) is from 0.05 to 5 parts by weight, more preferably from 0.1 to 2 parts by weight. The solid content concentration of the coating composition is
Although it varies depending on the type of the coater and the use of the paper or the composition, generally about 20 to 72 parts by weight is preferable.

In general, the water-soluble resin (III) used in the present invention is added and mixed at the time of preparing a paper coating composition. However, the effect of the present invention can be obtained by adding and mixing it in advance to a pigment slurry or an aqueous binder. it can.

The paper coating composition of the present invention includes, as other components, a dispersant, a viscosity / fluidity regulator, an antifoaming agent, a preservative, a lubricant,
Water retention agents, coloring agents such as dyes and colored pigments, and the like can be added as necessary.

The paper coating composition of the present invention may be formed on a paper substrate by a conventionally known method, that is, a blade coater, an air knife coater, a bar coater, a size press coater, a gate roll coater, a cast coater or the like. Applied. Thereafter, necessary drying is performed, and if necessary, a smoothing treatment is performed with a super calender or the like, whereby a coated paper can be manufactured.

<Effect of the Invention> The coated paper obtained by using the paper coating composition of the present invention in this manner is excellent in ink receptivity, water resistance, and particularly excellent in blister resistance, and has a formaldehyde odor. It has various excellent and effective characteristics.

In the present invention, “paper” in the paper coating composition has a broad meaning, and includes paper and paperboard in a narrow sense.

<Example> Hereinafter, the present invention will be described in more detail with reference examples and examples. All percentages in the text indicate weight%. The viscosity is a value at 25 ° C.

Reference Example 1 A four-necked flask equipped with a thermometer, a reflux condenser and a stirring rod was charged with 146.2 g (1.0 mol) of triethylenetetramine and 180.2 g (3.0 mol) of urea, and heated at an internal temperature of 120 to 140 ° C.
Heating was performed for an hour to perform a deammonification reaction. Then water 150.
4 g was added to obtain a resin aqueous solution. Further 37% formalin 5
After adding 6.8 g (0.7 mol) and reacting at 70 ° C. for 4 hours, 7
The pH of the system was adjusted to 4.0 with 0% sulfuric acid and reacted at 70 ° C. for 4 hours. Then adjust the pH to 7.0 with aqueous sodium hydroxide solution and adjust the concentration to 6
A 0% aqueous solution of a water-soluble resin having a viscosity of 350 cps was obtained.

Reference Example 2 Triethylenetetramine 146.
2 g (1.0 mol) and 60.1 g (1.0 mol) of urea were charged, and the internal temperature was 1
It heated at 40-160 degreeC for 3 hours, and performed the deammonia reaction. After cooling to 120 ° C, 120.1 g (2.0 mol) of urea was further charged and heated at an internal temperature of 120 to 130 ° C for 2 hours to perform a deammonification reaction. Thereafter, 134.9 g of water was added to obtain a resin aqueous solution. Add 81.2 g (1.0 mol) of 37% formalin and add 70%
After the reaction at 4 ° C. for 4 hours, the pH of the system was adjusted to 4.0 with 70% sulfuric acid, and the reaction was carried out at 70 ° C. for 4 hours. Thereafter, the pH was adjusted to 7.0 with an aqueous solution of caustic soda to obtain an aqueous solution of a water-soluble resin having a concentration of 60% and a viscosity of 230 cps.

Reference Example 3 103.2 g of diethylenetriamine was added to the same apparatus as in Reference Example 1.
(1.0 mol) and urea 120.1 g (2.0 mol)
A deammonification reaction was performed at 0 to 140 ° C for 2 hours. Thereafter, 33.6 g of water was added to obtain a resin aqueous solution. Further, 81.2 g (1.0 mol) of 37% formalin was added and reacted at 70 ° C. for 4 hours. Then, the pH of the system was adjusted to 4.0 with 70% sulfuric acid, and the reaction was performed at 70 ° C. for 4 hours. Thereafter, the pH was adjusted to 7.0 with an aqueous solution of caustic soda to obtain an aqueous solution of a water-soluble resin having a concentration of 60% and a viscosity of 540 cps.

Reference Example 4 After performing a deammonification reaction in the same manner as in Reference Example 1, water 21
5.4 g was added, and 64.8 g (0.7 mol) of epichlorohydrin was further added, followed by reaction at 70 ° C. for 4 hours. An aqueous solution of a water-soluble resin having a concentration of 60%, a viscosity of 300 cps and a pH of 6.2 was obtained.

Reference Example 5 An aqueous solution 46 of a water-soluble resin obtained in the same manner as in Reference Example 1.
To 5.5 g, 14.6 g (0.1 mol) of triethylenetetramine and 9.1 g of water were further added to obtain an aqueous solution of a water-soluble resin having a concentration of 60%, a viscosity of 340 cps and a pH of 8.0.

Reference Example 6 Triethylenetetramine 43.9 was added to the same apparatus as in Reference Example 1.
g (0.3 mol) and 140.3 g of water were added, and 166.6 g (1.8 mol) of epichlorohydrin was added dropwise while maintaining the internal temperature at 50 ° C or lower. Further, 465.5 g of an aqueous resin solution obtained in the same manner as in Reference Example 1 was added, and the mixture was reacted at 50 ° C. for 1 hour.
An aqueous solution of a water-soluble resin having a viscosity of 60%, a viscosity of 300 cps and a pH of 6.5 was obtained.

Comparative Reference Example 1 A four-necked flask equipped with a thermometer, a reflux condenser, and a stirring rod was charged with 146.2 g (1.0 mol) of triethylenetetramine and 30.0 g (0.5 mol) of urea.
Heating was performed for an hour to perform a deammonification reaction. Thereafter, 73.1 g (0.5 mol) of adipic acid was charged, and a dehydration amidation reaction was performed for 5 hours while maintaining the internal temperature at 150 to 160 ° C. Then the internal temperature is reduced to 13
Cool to 0 ° C and charge 120.1 g (2.0 mol) of urea,
A deammonification reaction was performed at 30 ° C. for 2 hours. Then water 284.
5 g was added to obtain a resin aqueous solution. 37% formalin 6
0.9 g (0.75 mol) was charged, and the pH of the system was adjusted to 4 to 5 with 70% sulfuric acid.
And reacted at an internal temperature of 70 ° C. for 4 hours. Thereafter, the pH was adjusted to 6.5 with an aqueous sodium hydroxide solution, the concentration was 50%, and the viscosity was 140 cp.
s of the resin aqueous solution was obtained.

Comparative Reference Example 2 The charged amount of urea was 90.1 g (1.5 mol), and the charged amount of water was 101.
The reaction was carried out in the same manner as in Reference Example 1 except that
A 60% aqueous resin solution of 0 cps and pH 7.0 was obtained.

Comparative Reference Example 3 The charged amount of urea was 300.3 g (5 mol), and the charged amount of water was 230.
The reaction was carried out in the same manner as in Reference Example 1 except that
A 60% aqueous resin solution of 0 cps and pH 7.0 was obtained.

Comparative Reference Example 4 A reaction was performed in the same manner as in Reference Example 1 except that the reaction after the addition of sulfuric acid was not performed, to obtain a 60% resin aqueous solution having a viscosity of 60 cps and a pH of 8.5.

Comparative Reference Example 5 A reaction was carried out in the same manner as in Reference Example 1 except that the charged amount of 37% formalin was 73.0 g (0.9 mol) and the charged amount of water was 144.2 g, and a 60% resin having a viscosity of 1600 cps and a pH of 7.0 was used. An aqueous solution was obtained.

Comparative Reference Example 6 The reaction was carried out in the same manner as in Reference Example 1, and the pH was further adjusted to 70% with sulfuric acid at pH 4.
It was adjusted to 0 to obtain a 60% resin aqueous solution having a viscosity of 350 cps.

Comparative Reference Example 7 The same reaction as in Reference Example 1 was carried out, and the pH was adjusted with an aqueous sodium hydroxide solution.
An attempt was made to adjust the amount to 11, but a large amount of precipitate was formed, and a good aqueous resin solution was not obtained.

Examples Using the aqueous solutions of the water-soluble resins obtained in Reference Examples 1 to 6 and Comparative Reference Examples 1 to 6, paper coating compositions having the formulations shown in Table 1 were prepared. However, in Comparative Reference Examples 2, 5, and 6, the coating composition had a high viscosity and the coating test could not be performed.

The prepared paper coating composition had a total solid content of 60% and a pH of about
As will be 9.0, was adjusted in each water and 10% aqueous sodium hydroxide solution, the fine paper of a basis weight amount 80 g / m ² using a wire rod, one side as the coating amount becomes 14 g / m ² or Coated on both sides. Immediately after application, dry with hot air at 120 ° C for 30 seconds, and then adjust the humidity at 20 ° C and 65% RH for 16 hours.
Super calendering was performed twice at 60 ° C. and a linear pressure of 60 kg / cm to obtain a coated paper. The coated paper thus obtained was subjected to tests for water resistance, ink acceptability, and blister resistance.
The test results are shown in Table 2.

 The test method is as follows.

Water resistance (a) Wet lab method About 0.1 ml of ion-exchanged water was dropped on the coated surface and rubbed seven times with a fingertip, and the elution amount was transferred to black paper to determine the elution amount with the naked eye.

 The judgment criteria were as follows.

Water resistance (poor) 1 to 5 (excellent) (b) Wet pick method Using an RI tester, wet the coated surface with a water supply roll and print, observe the peeling state with the naked eye, Poor) 1 to 5 (excellent) were determined.

Ink acceptability (A) Method A Using a RI tester (Meiji Seisakusho), the coated surface was wetted with a water supply roll and then printed, and the ink acceptability was visually observed.

 Ink acceptability (poor) 1 to 5 (excellent).

(B) Method B Using an RI tester, printing was performed while water was kneaded into the ink, and ink acceptability was visually observed.

 Ink acceptability (poor) 1 to 5 (excellent).

Blister resistance Double-sided printing was performed on double-sided coated paper using an ink for rotary offset printing using an RI tester, and after wetting, the paper was immersed in a heated silicone oil bath, and the amount of blister generated was visually determined.

 Blister resistance (poor) 1 to 5 (excellent).

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Claims (8)

(57) [Claims] (1) A pigment (I), an aqueous binder (II), and a condensation reaction product (a) of an alkylenediamine or a polyalkylenepolyamine with a urea, and an aldehyde (b) or an epihalohydrin or α, γ-
It is obtained by reacting a dihalo-β-hiroline (c). When the aldehyde (b) is used, the reaction is carried out at pH
Done below 7 or first at pH 8-12, then
A paper coating composition comprising a water-soluble resin (III) which has been prepared at a pH of 7 or less. 2. The paper coating composition according to claim 1, wherein the alkylenediamine or polyalkylenepolyamine is diethylenetriamine or triethylenetetramine. 3. The paper coating composition according to claim 1, wherein the urea is used in an amount of 0.5 to 1.0 mol based on 0.1 mol of the primary and secondary amino groups of the alkylene diamine or polyalkylene polyamine. Stuff. 4. A water-soluble resin (III) comprising a condensation reaction product (a)
The paper coating according to any one of claims 1 to 3, which is obtained by reacting aldehydes (b) with aldehydes, wherein the reaction is first performed at pH 8 to 12, and then at pH 7 or less. Engineering composition. 5. The paper coating composition according to claim 1, wherein the aldehyde (b) is formaldehyde or glyoxal. 6. The paper coating composition according to claim 1, wherein the water-soluble resin (III) has a 60% water-soluble viscosity at 25 ° C. of 100 to 1000 cps and a pH of 6 to 10. Stuff. 7. A condensation reaction product (a) of a pigment (I), an aqueous binder (II), an alkylenediamine or a polyalkylenepolyamine with a urea, and an aldehyde (b) or an epihalohydrin or an α, γ-dihalo compound. -Β-Hyrolines (c) are reacted to obtain aldehydes (b). When the aldehydes (b) are used, the reaction is carried out at pH 7 or lower, or after the reaction is carried out first at pH 8 to 12, pH7
1. A paper for a paper, comprising: a water-soluble resin (III) which has been carried out below; and a member (IV) selected from a polyalkylene polyamine and a reaction product of a polyalkylene polyamine and a quaternizing agent. Coating composition. 8. An aldehyde (b) or an epihalohydrin or an α, γ-dihalo compound is added to a pigment (I), an aqueous binder (II), or a condensation reaction product (a) of an alkylenediamine or a polyalkylene polyamine with a urea. -Β-Hyrolines (c) are reacted to obtain aldehydes (b). When the aldehydes (b) are used, the reaction is carried out at pH 7 or lower, or after the reaction is carried out first at pH 8 to 12, pH7
Paper containing a product (V) obtained by further reacting a reaction product of a polyalkylene polyamine and a quaternizing agent with a water-soluble resin (III) that has been performed below. Coating composition.