JPH0154476B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a binder for coated paper, particularly (A)
Acrylic acid amide or methacrylic acid amide 55~
87% by weight, B) 5-15% by weight of N-methylolmethacrylic acid amide, C) General formula

[Formula] [where X is hydrogen or methyl group; Y is glycidyl group, 3-chloro-2-hydroxypropyl group, or general formula a)

[Formula] b) (-CH ₂ CH ₂ O-)nH, c) -CH ₂ CH ₂ NR ₁ R ₂ or d) -CH ₂ CH ₂ N
(R ₁ R ₂ R ₃ ) represents Z (where R is an alkyl group, aryl group, or hydroxyalkyl group; R ₁ , R ₂ , R ₃
each represents an alkyl group; Z represents a hydroxyl group or a halogen anion; n represents an integer of 2 to 5, respectively. D) 5-15% by weight of at least one acrylic ester or methacrylic ester represented by D) 3-15% by weight of at least one alkyl ester of acrylic acid or methacrylic acid, acrylonitrile or methacrylonitrile It is an object of the present invention to provide a binder for coated paper comprising an aqueous solution of a water-soluble copolymer with. In recent years, the development and practical application of magnetic recording methods and thermal recording methods have been actively progressing, and among them, thermal recording methods (1) do not require a phenomenon process because of primary color development;
() Easy to assemble and maintain the device; () The heat-sensitive recording sheet has a feel similar to plain paper and is relatively inexpensive;
For this reason, it has been put to practical use in the fields of computer output, printers such as calculators, recorders of medical measuring machines, facsimile machines, automatic ticket vending machines, thermal copying, etc. Magnetic recording paper and heat-sensitive recording paper used in this magnetic recording method and thermal recording method are usually manufactured in the same manner as so-called general coated paper such as art paper and coated paper. That is, in the production of art paper, coated paper, etc., inorganic pigments such as barium sulfate, titanium oxide, calcium carbonate, satin white, clay, and kaolin are added to casein, starch, or synthetic base paper in the form of rolls or sheets. It is coated using a coating liquid dispersed in water together with various binders such as latex, and then dried. Furthermore, mechanical processing such as supercalendering is performed. Generally, these binders also have the function of uniformly dispersing the pigment in the coating liquid, but a dispersant may be used separately. Similarly, magnetic recording paper uses magnetic materials such as γ-iron oxide, and thermal recording paper uses leuco dye coloring components such as leucolactone compounds and spiropyran compounds, phenolic compounds, and organic acids. It is obtained by coating a paper substrate (including synthetic pulp paper and synthetic paper as well as wood pulp paper) with a coating liquid in which a reactant and a binder are uniformly dispersed in water. As binders for general coated papers such as art paper and coated paper, and various coated papers such as magnetic recording paper and thermal recording paper, coated materials such as pigments, dyes, magnetic powders, and various other additives are used. Good dispersibility and adhesion,
It must meet various requirements such as being able to obtain a homogeneous and strong coating film, having good water resistance, good viscosity stability, excellent workability, and being economically inexpensive. However, it is further required that the aforementioned leuco dye-based binder for thermal recording paper has good thermal response and does not cause fogging, thermal head fusion, thermal head deterioration, etc. Conventionally known binders for coated paper include, for example, polyvinyl alcohol, starch and modified products thereof, casein, gelatin, soybean protein, carboxymethylcellulose, gum arabic, methylcellulose, hydroxyethylcellulose, sodium alginate, polyacrylamide, and polyacrylic acid. Water-soluble substances such as soda, alkali-modified styrene-maleic anhydride copolymers, and styrene.
Butadiene copolymer, styrene-butadiene-acrylonitrile copolymer, ethylene-vinyl acetate copolymer, vinylidene chloride-acrylic acid ester copolymer, vinylidene chloride-acrylonitrile copolymer, acrylonitrile-acrylic acid ester copolymer, polyurethane resin , chlorinated polypropylene resin, butadiene/acrylonitrile copolymer, aqueous emulsion of vinyl acetate resin, etc. are known. However, water-soluble substances such as those mentioned above, except for styrene-maleic anhydride alkali-modified substances, have poor water resistance, and therefore, a water-resisting agent is usually used in combination, but there are various drawbacks and it is difficult to obtain practically satisfactory results. . On the other hand, although styrene-maleic anhydride alkali-modified products give good results in terms of water resistance, when used as a binder for the above-mentioned heat-sensitive recording paper, they have the drawback of easily causing thermal head deterioration. Similarly, aqueous emulsions made from synthetic resins have high water resistance, but they also have drawbacks such as fogging the skin and causing thermal head fusion, so they cannot be said to be sufficient for practical use. hard. The present inventors have conducted various studies with the aim of developing a binder for coated paper that satisfies the above requirements and is particularly excellent in practical use for leuco dye-based heat-sensitive recording paper. It was discovered that the desired object could be achieved by using an aqueous solution of a copolymer of acid amide or methacrylic amide, N-methylol methacrylic amide, and acrylic ester or methacrylic ester, and the present invention was completed. I came to the conclusion. The base polymer in the coated paper binder of the present invention contains (A) 55 to 87% by weight of acrylic acid amide or methacrylic acid amide as copolymerized components, and B) N-
5-15% by weight of at least one type of methylolmethacrylic acid amide, C) General formula

[Formula] [However, X is hydrogen or methyl group; Y is glycyl group,
3-chloro-2-hydroxypropyl group or general formula a)

[Formula] b) (-CH ₂ CH ₂ O -) nH, c) - CH ₂ CH ₂ NR ₁ R ₂ or d) -
CH ₂ CH ₂ N(R ₁ R ₂ R ₃ )Z (wherein R is an alkyl group, an aryl group, or a hydroxyalkyl group;
R ₁ , R ₂ and R ₃ are each an alkyl group; Z is a hydroxyl group or a halogen anion; n is an integer of 2 to 5, respectively. ] 5 to 15% by weight of at least one acrylic ester or methacrylic ester represented by D) 3 to 15% by weight of at least one alkyl ester of acrylic acid or methacrylic acid, acrylonitrile or methacrylonitrile % by weight, and R in the above general formula specifically includes an alkyl group such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, 2-ethylhexyl, or any of these. hydroxyl group-substituted product, phenyl, cresyl, p-t
- Aryl group such as butylphenyl, or R ₁ to _{R 3}
Examples include lower alkyl groups such as methyl, ethyl, and propyl. That is, in order to satisfy the above requirements as a binder for coated paper, the present inventors have found that the base polymer must have affinity with paper and high binding strength, and must also be water-soluble. However, the molecular design was based on the idea that it should not be unnecessarily easily soluble and should be difficult to dissolve in water after being applied to paper and dried, and the polymer composition should be acrylic acid or methacrylic acid amide. Since a single system has low water resistance and is of little practical use, it is necessary to copolymerize it with other structures having alkyl groups or monomers with similar physical properties at a predetermined ratio to introduce alkyl groups into the polymer side chains. In order to improve water resistance, we have introduced not only alkyl groups but also groups containing epoxy groups, alkoxy groups, amino groups, cyano groups, etc. to improve water resistance, as well as improve affinity with paper and bonding strength. This has further improved its performance as a binder. Regarding the weight ratio of each monomer in the copolymer, for the purpose of improving water resistance, it is sufficient to increase the ratio of component monomers B) to D), but if the composition ratio is increased too much, the water solubility of the copolymer may be lost. In some cases, cross-linking between copolymers may occur, resulting in increased viscosity and
Gelation occurs and the desired copolymer cannot be obtained. Although there are no particular restrictions on the production of the copolymer of the present invention, it is usually prepared, for example, by the following method. However, of course, it may be manufactured by other methods. That is, in an aqueous solution having a monomer concentration of 10 to 30% by weight, preferably 15 to 25% by weight, which is the sum of component (A) and components (B) to (D), persulfate or persulfate as a catalyst, or amine or sulfurous acid are added to the solution as a catalyst. Add a redox system with salt and allow to react at about room temperature (5 to 30°C) for about 0.5 to 2 hours. As persulfates and sulfites used as catalysts, water-soluble salts such as sodium, potassium, and ammonium salts are suitable, and as amines, for example, monoethanolamine, hexamethylene diamine, aniline, etc. Primary amines such as diethanolamine, secondary amines such as monomethylaniline, and tertiary amines such as triethanolamine, dimethylaniline, hyridine, and picoline may be used. Among these, a redox catalyst using a combination of ammonium persulfate and triethanolamine is particularly preferred as it is the most effective. There is no particular restriction on the amount of catalyst used, but it is usually 0.1 persulfate per monomer.
It is desirable to use about 2.0% by weight and 0.5 to 20% by weight of amine. The polymerization temperature is initially carried out at room temperature, but increases as the polymerization begins, and usually reaches a final temperature of about 70°C. Cooling is not necessary unless there is localized overheating. In order for the polymer film formed on the paper coated as the base polymer for the coating solution to have sufficient strength, the higher the molecular weight of the polymer, the better.
On the other hand, if the molecular weight of the coating liquid itself is too high, the viscosity will be high and the workability will be poor. For a copolymer liquid with relatively high film strength and good workability, a viscosity of a 20% aqueous solution at room temperature of about 2,000 to 60,000 CP is appropriate, and to prepare an aqueous copolymer solution within this range, the amount of catalyst used is as above. Must be within the range.
The monomer concentration is selected from the above range from the viewpoint of adjusting the viscosity of the copolymer aqueous solution obtained as a result of polymerization to a suitable range. The binder for coated paper of the present invention is particularly excellent in practical use for leuco dye-based heat-sensitive recording paper, and in this use, it strengthens the binding of color former components, color developer components, fillers, etc. to the base paper. The color-forming compounds serving as color-forming agent components are leucolactone compounds and spiropyran compounds, and representative examples thereof are as follows.
However, these specific examples do not limit the present invention. As the coloring component, a leuco form of a triphenylmethane dye represented by the following general formula () or a leuco form of a fluoran dye represented by the following formula (2) can generally be used alone or in combination. Rx, Ry, Rz are hydrogen, hydroxyl group, halogen, alkyl group, nitro group, amino group, dialkylamino group, monoalkylamino group, allyl group, Z is an atom necessary to form a heterocycle and represents O, S . Compound 3,3-bis(P-dimethylaminophenyl) belonging to formula ()
-phthalide 3,3-bis(P-dimethylaminophenyl)
-6-dimethylaminophthalide (crystal violet lactone) 3,3-bis(P-dimethylaminophenyl)
-6-aminophthalide 3,3-bis(P-dimethylaminophenyl)
-6-nitrophthalide 3,3-bis(P-dibutylaminophenyl)
-phthalide 3,3-bis(P-dimethylaminophenyl)
-4,5,6,7 tetrachlorophthalide () Compound belonging to the formula 3-dimethylamino-6-methoxyfluoran 7-acetamino-3-dimethylaminofluoran 3-dimethylamino-5,7-dimethylfluoran 3-diethylamino-5,7-dimethylfluorane 3,6-bis-β-methoxyethoxyfluorane 3,6-bis-β-cyanoethoxyfluorane 3-diethylamino-6-methyl 7-P-butylanilino Fluoran 3-diethylamino-6-methyl-7-chlorofluoran Also, as a color developer component that reacts with the above dye to develop color, phenol compounds or organic acids are effective. It is desirable that the material is solid and has the property of liquefying or vaporizing at 50°C or higher. Phenol compounds include 4,4'-isopropylidene diphenol (bisphenol A), 4-tert-butylphenol, 4-tert-octylphenol, 4-tert-amylphenol, P-phenylphenol, 2,2-bis(P- 2,2-bis(P-hydroxyphenyl)isohexane Organic acids include stearic acid, benzoic acid, salicylic acid, succinic acid, gallic acid, and acrylic acid, methacrylic acid, and itaconic acid. Examples include homopolymerized oligomers of organic acid monomers and copolymerized oligomers thereof with styrene, acrylamide, etc. The above-mentioned color forming agent component and color developing agent component can be used alone or, if necessary, two or more kinds can be used in an appropriate mixture. Examples of the filler include inorganic substances such as calcium carbonate, talc, titanium oxide, clay, and kaolin, and synthetic resins such as polystyrene. These can be used alone or in combination of two or more. The appropriate mixing weight ratio of the color former, color developer, filler, and binder is 1:0.1 to 1:0.3; if the amount of binder is less than this ratio, the adhesive strength will be weak and the performance as a binder will be lost. Moreover, if there is a large amount of binder, the color development sensitivity will decrease. In producing the heat-sensitive coating composition, in addition to the above-mentioned color forming agent, developer, filler binder, wax or the like may be added to prevent heat adhesion if necessary. As described above, the present invention provides a coated paper that is practically excellent as a binder for coated paper, especially as a binder for leuco dye-based heat-sensitive recording paper.
It can also be used in combination with other water-soluble and water-dispersible binders, and its range of applications is wide. The present invention will be specifically explained below using examples. Example 1 (a) Method for manufacturing binder In a three-necked flask equipped with a thermometer and a nitrogen inlet tube, 77 parts of acrylamide, 10 parts of N-methylolmethacrylic acid amide, 5 parts of methacrylic acid monoester of diethylene glycol, Prepare 8 parts of methyl methacrylate and 400 parts of water and nitrogen bubbling 1
After an hour, the liquid temperature was adjusted to 20°C, and 8 parts of triethanolamine and 0.8 parts of ammonium persulfate were each added as aqueous solutions to initiate polymerization. Polymerization was continued for 1 hour after reaching the maximum temperature to obtain a 20% aqueous solution of the copolymer. The viscosity of this copolymer aqueous solution is at 20℃.
It was 22000CP. Dilute this with water to make a concentration of 10
The aqueous solution adjusted to % was used as a binder. (b) Preparation of heat-sensitive coating liquid () 4 parts of crystal violet lactone,
20 parts of binder, 26 parts of water and 16 parts of bisphenol A, 20 parts of binder
1 part of calcium carbonate, 3 parts of water, and 11 parts of water are mixed separately for 3 hours in a ball meal to form a dispersion liquid. Before use, these are combined and mixed thoroughly with stirring to form a thermal coating liquid (A). I got it. Similarly, it consists of () 4 parts of 3-dimethylamino-5,7-dimethylfluorane, 20 parts of binder, 26 parts of water and () 16 parts of P-phenylphenol, 20 parts of binder, 3 parts of talc, and 11 parts of water. The dispersion liquid was mixed to obtain a heat-sensitive coating liquid (B). For comparison, all of the above heat-sensitive coating liquids (A ) Thermal coating solution
I got (C). (c) Manufacturing and testing of recording paper 60% each of the heat-sensitive coating liquids (A), (B) and (C) obtained in (b)
g/ ^m2 Heat-sensitive recording paper coated on the surface of high-quality paper using a wire bar and dried to a coating weight of 4.0g/ ^m2
Obtained (A), (B) and (C). These thermal recording papers are 130
When printed at °C, Macbeth density A: 0.86, B:
0.85, C: 0.86. Also, water resistance is (A) and (B)
After exposing the printed area to 0.2 g of water for 1 minute, the printed area was strong enough to not peel off even if the printed area was traced with a finger. However, when a similar test was conducted for (C), peeling of the printed area was observed. Examples 2 to 7 Similar tests were conducted using the same compositions for the various binder liquids shown below, and all were found to have excellent performance almost equivalent to the above. (2) Acrylic acid amide 75 parts/N-methylolmethacrylic acid amide 10 parts/3-phenoxy-2-hydroxypropyl acrylate 5 parts/acrylonitrile 10 parts Copolymer (temperature of 20% aqueous solution 20
10% aqueous solution (3) 72 parts of acrylic acid amide/10 parts of N-methylolmethacrylic acid amide/10 parts of dimethylaminoethyl methacrylate/8 parts of methyl methacrylate copolymer (viscosity 20000CP at °C) (concentration 20%) Viscosity of aqueous solution at temperature 20℃
22000CP) 10% aqueous solution (4) 75 parts of acrylamide/10 parts of N-methylol methacrylic acid amide/5 parts of glycidyl methacrylate/10 parts of ethyl acrylate copolymer (conc.
20% aqueous solution temperature 20℃ viscosity 25000CP) 10%
Aqueous solution (5) 65 parts of methacrylic acid amide/10 parts of N-methylol methacrylic acid amide/15 parts of trimethylacryloyloxyethylammonium chloride/10 parts of methacrylonitrile copolymer (viscosity of 20% aqueous solution at 20°C viscosity 28000CP) 10% aqueous solution (6) 75 parts of acrylic acid amide/10 parts of N-methylolmethacrylic acid amide/3-chloro-acrylic acid
5 parts of 2-hydroxypropyl/10 parts of methyl methacrylate copolymer (temperature of 20% aqueous solution
10% aqueous solution (7) of methacrylic acid amide (75 parts) / N-methylolmethacrylic acid amide (10 parts) / 3-butoxy-2-hydroxypropyl acrylate (5 parts) / ethyl acrylate (10 parts) copolymer (Temperature of 20% aqueous solution
10% aqueous solution with viscosity 23000CP) at 20℃.

Claims (1)

[Scope of Claims] 1 (A) Acrylic acid amide or methacrylic acid amide 55 to 87% by weight, B) N-methylol methacrylic acid amide 5 to 15% by weight, C) General formula [Formula] [However, X is Hydrogen or methyl group; Y is glycidyl group, 3-chloro-2-hydroxypropyl group or general formula a)
[Formula] b) (-CH ₂ CH ₂ O-)nH, c) -CH ₂ CH ₂ NR ₁ R ₂ or d) -CH ₂ CH ₂ N
(R ₁ R ₂ R ₃ ) represents Z (where R is an alkyl group, aryl group, or hydroxyalkyl group; R ₁ , R ₂ , R ₃
each represents an alkyl group; Z represents a hydroxyl group or a halogen anion; n represents an integer of 2-5. D) 5-15% by weight of at least one acrylic ester or methacrylic ester represented by D) 3-15% by weight of at least one alkyl ester of acrylic acid or methacrylic acid, acrylonitrile or methacrylonitrile A binder for coated paper consisting of an aqueous solution of a water-soluble copolymer with.