JPS58126394A - Paper coating composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating composition for paper, and its purpose is particularly to improve the water resistance of the coating layer necessary for offset printing,
For paper that has excellent performance as a coated paper for printing, such as excellent ink transfer, no coloration, extremely low formaldehyde generation from coated paper, and excellent blister resistance in rotary offset printing. An object of the present invention is to provide a coating composition.

Conventionally, paper coating compositions containing pigments and water-based binders as main components and supplementary ingredients such as waterproofing agents are applied to paper base materials to produce coated paper with good printability. is known. In recent years, there have been remarkable developments in paper manufacturing technology and printing technology, and in this connection, there has been a demand for coating compositions that can meet new demands. For example, when coating at high speed with a blade coater by increasing the solid fraction in the coating composition to increase productivity during coated paper manufacturing, the curling of the coating composition increases. In addition, with the increase in printing speed, the increasing quality of printed materials, and the spread of offset printing and offset rotary printing, the water resistance of the coating layer, transferability of printing ink, and blister resistance have improved. It is hoped that the performance will be even better than before.

Many proposals have been made to improve these performances, such as modifying the aqueous binder component and improving the adjuvant component, but none have been found to be sufficient. Water resistance (wet strength) can be effectively improved, for example, by increasing the amount of water-based binder component relative to the pigment, but on the other hand, there are drawbacks such as reduced ink transferability during printing. There is no effective method to improve this problem, and the current method is to use a water resistant agent at °C as an auxiliary ingredient. A typical example is a water-resistant agent for water-based binders, but while all of the previously used or proposed water-resistant agents have effective advantages, they also have serious drawbacks, and are not always satisfactory in practical terms. There was no string.

For example, the melamine-formaldehyde initial condensate has insufficient transferability of printing ink on coated paper, and when the pEl of the coating composition is high, the water resistance effect is insufficient, and free formaldehyde from coated paper There were problems such as a large amount of waste generated, which was unfavorable in terms of work hygiene and environment. The reaction product of polyamide polyurea and formaldehyde alone has excellent anti-transfer properties of printing ink on coated paper, has good water resistance, and has a %IJ point with a small amount of free formaldehyde generated from coated paper. However, especially when the coating composition has a high pE1
At present, it is inferior to the water effect and the effect of improving rising properties and ink transfer properties.

In addition, dialdehydes such as glyoxal may cause coloring of the coated paper, deterioration of water resistance over time, and poor transfer properties of E11 ink, and polyvalent metal salts such as zirconium may cause significant thickening of the coating solution. However, the workability is poor. Furthermore, the ketone-formaldehyde initial condensate is inferior in water resistance and printing ink transferability improvement effect.

Based on this, the present inventors have developed a coating composition for paper that is superior in water resistance when the pH of the coating composition is high, is free from the various drawbacks mentioned above, and is extremely effective in improving ink transfer properties during printing. In order to develop a coating composition, as a result of examining the amount of iron, a paper coating composition containing an aqueous thermosetting resin solution produced by a specific method as a hydrating agent satisfied the above objectives and was extremely effective. The present inventors have discovered that the present invention has excellent effects, and have completed the present invention.

That is, the present invention mainly consists of a pigment and an aqueous binder,
Furthermore, it is a paper coating composition characterized by containing a mixture of a reaction product of polyamide polyurea and formaldehyde and a polyalkylene polyamine, or a reaction product thereof.

In the present invention, polyamide polyurea refers to a product obtained by subjecting urea and polyalkylene polyamine to a de-ammonia reaction, followed by dehydration condensation with a dibasic carbonic acid, and further de-ammonia reaction with urea [hereinafter referred to as polyamide polyurea (A). ], or a product obtained by dehydration condensation of a polyalkylene polyamine and a dibasic carboxylic acid, and then a deammonia reaction with urea [hereinafter referred to as polyamide polyurea (B)].

In the present invention, polyalkylene polyamines are polyalkylene polyamines having two primary amino groups and at least one secondary amino group in the molecule, such as diethylenetriamine, triethylenetetramine, tetraethylene Pentamine, iminohispropylamine, 8-asahexane-1,
Examples thereof include 6-diamine, 4,7-diazadecane-1,1,0-diamine, and the like. These polyalkylene polyamines can be used not only alone but also as a mixture of two or more.

Further, dibasic carboxylic acids used in the present invention include aliphatic carboxylic acids such as succinic acid, glutaric acid, adipic acid, sebacic acid, maleic acid, and fumaric acid;
Aromatic carboxylic acids such as isophthalic acid, terephthalic acid and mixtures thereof may be mentioned.

In the present invention, the conditions for the general production of polyamide polyurea are as follows. Production method of polyamide polyurea [A) The molar ratio of urea and polyalkylene polyamine is approximately 1.
: It is preferable to carry out the reaction at around 2, and the reaction temperature is 100
~200°C preferably/A) is suitably 120~170''C, and the reaction is carried out for 2~8 hours while removing generated ammonia from the system.Next, 03~0.7'' is added per mole of polyalkylene polyamine.
Dehydration condensation with mol of dibasic carboxylic acid. At a reaction temperature of 120 to 250°C, preferably 140 to 200″C,
The reaction is carried out for 2 to 10 hours while removing the produced water from the system. 1. The condensation reaction product thus obtained is further reacted with urea. 9 The amount of urea is determined by 0.2 to 1 mole of secondary amino group
1.5 moJL/preferably 0.5 to 1.1 mole. The reaction temperature is preferably 100 to 180°C, <120 to
The temperature is 150°C, and the reaction is carried out at this temperature for 1 to 5 hours while removing generated ammonia from the system. In this way, polyamide polyurea "A" is obtained.

0 Polyamide Polyurea CB] The reaction between the polyalkylene polyamine and the dibasic carboxylic acid is carried out at a temperature of 120 to 250°C, preferably 140 to 200°C.
C. for 2 to 10 hours while removing produced water from the system.Preferably 1.4 to 8.0 moles of polyalkylene polyamine per 1 mole of dibasic carboxylic acid.
;t The reaction is carried out in a molar ratio of 1.8 to 2.5 mol, and the dehydration condensation reaction product thus obtained is then reacted with urea. The amount of urea used is 0.2 to 1.0 mol, preferably 0.4 to 0.8 mol, per 1 mol of amino groups in the raw material polyalkylene polyamine. The reaction temperature is 1
The reaction is carried out at a temperature of 00 to 180°C, preferably 120 to 150°C, for 1 to 5 hours while removing generated ammonia from the system. As a method of charging urea, it is possible to charge the required amount all at once and react, or to charge a portion of the required amount and complete the deammonification reaction, then charge the remaining urea and perform the deammonification reaction again. be. In this way, polyamide polyurea [B) is obtained.

The polyamide polyurea obtained as described above is dissolved in water and reacted with formaldehyde.
~60% by weight aqueous solution and 0.2 to 1.0 per mole of total urea used to synthesize the polyamide polyurea.
mol, preferably 0.8 to 067 mol of formaldehyde at 40 to 80°C for 0.5 to 10 hours under acidic or alkaline conditions. It is preferable to carry out the reaction under acidic conditions.

The reaction product of the polyamide polyurea and formaldehyde obtained as described above is further reacted with a polyalkylene polyamine or used as a mixture. When mixing, the reaction product of polyamide polyurea and formaldehyde and polyalkylene polyamine may be mixed separately into the paper coating composition, or the reaction product of polyamide polyurea and formaldehyde and polyalkylene polyamine may be mixed in advance. The mixture may be mixed and added to the boat coating composition.

(9) The amount of polyalkylene polyamine used is 0.1 to 8.0 mol, preferably 0.2 to 1.5 mol, per 1 mol of dibasic carboxylic acid used to synthesize the polyamide polyurea. .

The composition for paper of the present invention is prepared in the same manner as in the conventional method, but in order to fully exhibit the effect, a reaction product of polyamide polyurea and formaldehyde and a polyalkylene polyurethane are used.
The mixture with amines or their reaction products is usually 0.05 to 5 weight percent, preferably 0.05 to 5 weight percent, based on the weight of the pigment.
It is blended in a range of 1 to 2% by weight.

As the waterproofing agent, only those specified in the present invention are sufficiently effective, but depending on the case, it is also possible to replace a part of them with other waterproofing agents.

As the aqueous binder and pigment used in preparing the paper coating composition of the present invention, conventionally known ones can be used as they are. Examples of the water-repellent binder include:
For example, starch, oxidized starch, modified starch, polyvinyl alcohol, casein, gelatin, carboxyl methyl cellulose, hydroxyethyl cellulose, water-soluble binders such as soybean protein, styrene-butadiene resin, vinyl acetate resin, ethylene- Examples include water emulsion and dispersion binders such as vinyl acetate resin and methyl methacrylate resin.

Further, examples of pigments include inorganic pigments such as kaolin clay, talc, titanium dioxide, aluminum hydroxide, calcium carbonate, satin white, barium sulfate, and organic pigments containing styrene, urea, etc. as main components, Each of these may be used alone, in two or more volumes, or in combination in any proportion.

The paper coating composition of the present invention includes, as other components, a dispersant, a thickener, a thinner, an antifoaming agent, a foam inhibitor, a preservative, an anti-mold agent, a cum control agent, a release agent, Coloring agents such as dyes and colored pigments, special performance imparting agents such as conductive agents, etc. may be added as necessary, and the effects of the present invention are not hindered by this.

Further, the concentration and other adjustment conditions of the coating composition of the present invention can be adjusted by methods similar to conventional methods. Coating is performed on the paper substrate using a commonly used method such as an air knife coater, roll coater, scythe press coater, or cast coater, followed by drying as necessary using a conventional method, and if necessary, using a supercalenter or machine calender. Coated paper can be manufactured by performing the following treatments.

The paper coating composition of the present invention obtained in this way has excellent stability of the coating solution without any color shock (significant thickening of the composition or agglomeration of pigments), and is coated onto a paper substrate. The coated paper obtained by applying this coating has excellent water resistance in the coating layer, generates significantly less formaldehyde, has excellent transferability, and has no coloration.Improved blister resistance in rotary offset printing. It has various excellent features that make it effective for both.

The present invention will be explained below with reference to Examples.

Reference Example 1 (1) Synthesis of sA fat [A] In a four-eye flask equipped with a thermometer, a reflux condenser, and a stirring bar, 292 v-(2 mol) of triethylenetetramine and 6 urea were added.
0i (1 mol) was charged and the reaction was carried out at 145 to 150°C for 4 hours while removing the generated ammonia from the system.
Next, adipic acid 146j9' (1 mol) was added, and 15
Linearization reaction was carried out at 0 to 155°C for 5 hours. 120℃
After cooling the urine to 125~
Deammonification reaction was carried out at 130°C for 2 hours. Thereafter, 1800 g of water was gradually added to obtain an aqueous solution of polyamide polyurea.

Next, 87% formalin 202.55' (2.5 mol)
was added, the PLI was adjusted to 5 with concentrated hydrochloric acid, stirred at 65°C for 4 hours, and then cooled to 25°C to form a thermosetting (18) resin [A] with a solid content of 30%. I got it.

(2) Synthesis of resin [B) Resin [A] was obtained in exactly the same manner as in (1), and then triethylenetetramine 785' (0.5 mol) and water 1709- were added, and 3 Stir and keep warm for an hour.
Thereafter, it was cooled to 25°C to obtain a thermosetting resin [B] with a solid content of 8'0%.

(3) Synthesis of resin 1"O] Diethylene triene 206F (2 moles), water 10D, and adipic acid 1461 (1 mole) were charged into a four-eye flask equipped with a thermometer, a reflux condenser, and a stirring bar. The temperature was raised to 150°C.Then, while distilling off the water produced, the temperature was raised to 150°C.
After incubating at 0 to 155°C for 6 hours, it was cooled at 180'ct, and 240y-(4 mol) of urea was charged.
Deammonia reaction was carried out for 8 hours while removing ammonia generated at 0° C. from the system. Thereafter, 640f of water was gradually added to obtain an aqueous solution of polyamide polyurea.

Next, 87% formalin 180P (1.6 mol) was added, the pH was adjusted to 4 with concentrated hydrochloric acid, the temperature was stirred at 70°C for 8 hours, and the solid content was 50%.
A thermosetting resin (r) was obtained.

(4) Synthesis of resin [D] Resin [C] was obtained in exactly the same manner as in (3), and then diethylenetriamine 146 P (1.0 mol),
and water 146! i' was added to obtain a thermosetting resin [D] with a solid content of 50%.

(5) Triethylenetetramine 365P (2
, 5 mol), water 2011 and adipic acid 146y-(
1 mol) was charged and subjected to dehydration condensation at 155 to 160°C for 4 hours. Next, 605 L (1 mol) of urea was charged, and 14
After performing the deammoniation reaction at 5 to 1.50°C, 180
The mixture was cooled to 240°C, further charged with urea 240!? (4 mol), and deammoniated at 130 to 140°C for 8 hours.Water 6505' was then added to obtain an aqueous solution of polyamide polyurea. 8796 formalin 16
2P (2 mol) was added and the pH was adjusted to 4.0 with 5096 sulfuric acid.
Reference Example 2 (1) Preparation of Coating Composition for Paper Pigment and 17 Using kaolin clay, calcium carbonate, and aluminum hydroxide, a polyacrylate-based dispersant was added to the pigment slurry, which was dispersed in water. Add the latex, then add an appropriate amount of the water resistant agent, stir well and mix.Finally, the pH of the composition is adjusted to 9.5 with a caustic soda aqueous solution, and the solid content is 55.
A paper coating composition was prepared in such a manner that the weight percentage was as follows. The basic blending ratios of components other than the water resistant agent in the composition are as shown in Table 1.

(2) Preparation of coated paper The composition obtained by the above method is coated!
Both sides of coated base paper with a rice scale of t85 Vm2 were coated with a dry solid content of about 15 P/ln2 on one side using a t85 Vm2 rice scale, and hot air drying was performed at 120°C for 30 seconds. Next, this coated paper was placed in a supercalenter (roll temperature 60°C).
, roll wire JE 60 Kf // (1), 2 times) 2
A test sample (17) subjected to humidity conditioning in 65% IL H at 0°C was subjected to various tests.

(3) Various test methods (A) Coating liquid physical properties (1) Coating] Two liquid p) 1 Glass electrode pH 1 used, measurement temperature 20°C (2) Coating liquid viscosity B type viscometer used, rotation speed 6 Orpm, measurement temperature 20°C (B) Physical properties ■Water resistance of coating film (A) Wet, Rul+ method Approximately 0.0% ion-exchanged water was applied to the coated paper surface. i m/(17
) It was dropped and rubbed with the fingertips 7 times to transfer the eluate to black, and elution 1 was determined visually.

The criterion amount was determined as follows.

1 Aqueous (poor) 1 to 5 (excellent) (Exit> Wet Pick method RI test! (manufactured by Mei Seisakusho) was used to moisten the coated surface with a water supply roll, then print, and the coated surface fell off, Observe the damage condition with both eyes,
The criteria for determining 1 is the same as the Wet Ziub method.

(ij IJ18L of formaldehyde from coated paper
-1041 Liquid phase extraction method (2) Conforms to the acetylacetone method. For formaldehyde I measurement, place a t-shirt in a polyethylene bag.
'JJ was used to prevent migration and divergence from other sources, and was used for measurement.

■Ink transferability of coated paper Printing was performed using the RI trial sales method as described below, and the ink transferability was observed and judged with the naked eye.
Poor).

(18) (b)　　　　A　Method Printing is done after dropping water onto the ink that is being mixed.

(b) Method B Printing is performed after the surface to be coated is moistened with a water supply roll.

→ C method Printing is performed by a combination of methods A and B described above.

■White discoloration and heat resistance of coated paper White discoloration of coated paper before and after heat treatment in a hot air dryer at 150°C for 30 minutes, in accordance with JiSi'-8128, and measure the B value using a Hunter reflectance meter. It was tested by

The thicker the number, the better the whitening.

■Blister resistance IL Using an ink for off-circle printing using an IL I tester, double-sided printing is performed, and after conditioning the humidity, the temperature is immersed in a heated silicone oil bath, and the lowest temperature at which blisters occur. shows.

(19) Table 1 Examples 1 to 6 Using the resin obtained in Reference Example 1, evaluation was performed by the method shown in Reference Example 2. The resins used and their formulations are shown in Table 2.

The performance test results are shown in Table 2.

Comparative Examples 1 and 2 Coating liquids were prepared in the same manner as in the examples except that the waterproofing agent and L7 resins [A] to [E] were not used, and performance evaluation was performed.

The formulation and performance test results are shown in Table 2.

Comparative Example 3 A coating liquid was prepared in the same manner as in the example except that resin [A] was used alone as a waterproofing agent, and performance evaluation was performed. The formulation and performance test results are shown in Table 2.

Comparative Example 4 A coating liquid was prepared in the same manner as in the example except that resin [C] was used alone as a waterproofing agent, and performance evaluation was performed. The formulation and performance test results are shown in Table 2.

(20) (21)

Claims (1)

[Claims] 1. A coating Tm for paper, which is mainly composed of a pigment and an aqueous binder, and further contains a mixture of a reaction product of polyamide polyurea and formaldehyde, and a polyalkylene polyamine, or a reaction product thereof.