JP2762452B2 - Recording material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a recording material (recording paper) used for recording with aqueous ink. More specifically, the present invention relates to a recording material which is excellent in color developing properties of ink, has high resolution, and is suitable for forming a recorded image having water resistance and light resistance.

<Conventional Technology> In an ink jet recording system, recording is performed by generating and flying minute droplets of ink by various operating principles and attaching the droplets to a recording material such as paper. This method is rapidly spreading as a recording method that generates little noise and can perform high-speed printing and multicolor printing.

In this ink jet recording, ordinary paper has been generally used as a recording material. However, with the improvement of the performance of the apparatus, such as high-speed recording and multi-color recording, and further expansion of the application, the recording material for inkjet has been required to have more advanced characteristics. . That is, in order to obtain a high-quality recorded image with a high resolution comparable to that of a color photograph, the recording material is required to (1) absorb ink quickly, and (2) when ink dots overlap, (3) the shape of the ink dot is close to a perfect circle and its periphery is smooth, and (4) the diameter of the ink dot does not become larger than necessary. (5) It is necessary to satisfy various requirements such as high density of the ink dots and the periphery of the dots is not blurred, and (6) excellent color development of the inks. Also, light resistance and light resistance have been required.

Various proposals have hitherto been made in order to meet such requirements, but to date no recording material satisfying these requirements in a well-balanced manner has been found.

For example, Japanese Patent Application Laid-Open No.
JP-A-49113 discloses a sheet in which a urea-formaldehyde resin powder is internally impregnated with a water-soluble polymer, and JP-A-55-5830 discloses an ink-absorbing coating layer on a substrate surface. And JP-A-55-51583 each disclose using a non-colloidal silica powder as a pigment in a coating layer. Although these recording materials have an improvement in ink absorbency, they have a serious problem in that the recorded images lack water resistance.

On the other hand, in order to make the recorded image water resistant, for example,
JP-A-56-84992 discloses that a recording material contains a cationic polymer such as polyethyleneimine or polyvinylpyridinium halide, and JP-A-59-20696 discloses that a dimethyldiallylammonium chloride polymer is contained in a recording material. Is disclosed. However, these recording materials also have the drawback that the water-resistance effect is still insufficient and the light resistance of the recorded image is reduced.

<Problems to be Solved by the Invention> The present inventors have excellent color development of ink, high resolution,
As a result of intensive studies to develop a recording material capable of forming a recorded image having water resistance and light resistance, a polymer containing N, N-dialkylaminopropyl (meth) acrylamide as at least a part of the constituent monomer was developed. The present inventors have found that a recording material that forms a recorded image having water resistance and light resistance can be obtained by including the composition in a coating layer provided in or on a substrate, and the present invention has been accomplished.

<Means for Solving the Problems> Accordingly, the present invention provides a coating layer provided in or on a substrate, a polymer of N, N-dialkylaminopropyl (meth) acrylamide, N, N-dialkylamino. Provided is a recording material containing a copolymer of propyl (meth) acrylamide with another vinyl monomer copolymerizable therewith and having substantially no carboxyl group, or a salt containing any of these. Is what you do. Hereinafter, a polymer and a copolymer having an amino group and a salt thereof defined herein are sometimes collectively simply referred to as a “polymer”. This molecular terminal of the polymer, will not be C ₆ or higher alkyl groups are introduced. N, N-dialkylaminopropyl (meth) acrylamide, which is an essential component as a constituent monomer of the polymer used in the present invention, is represented by the formula (Wherein, R ¹ represents hydrogen or methyl, and R ² and R ³ each represent alkyl). Specific examples of such N, N-dialkylaminopropyl (meth) acrylamide include N, N-dimethylaminopropylacrylamide,
N, N-dimethylaminopropyl methacrylamide, N, N
-Diethylaminopropylacrylamide, N, N-diethylaminopropylmethacrylamide and the like.

In the monomer unit constituting the polymer used in the present invention, N,
The molar fraction of N-dialkylaminopropyl (meth) acrylamide is generally 0.1 or more, and when it is used as a copolymer, other components that can be copolymerized with the N, N-dialkylaminopropyl (meth) acrylamide Is usually 0.9 or less. The molar fraction of N, N-dialkylaminopropyl (meth) acrylamide is 0.
If it is less than 1, the water resistance after ink-jet recording is not sufficiently exhibited, so that it is not so recommended to extremely reduce the amount of N, N-dialkylaminopropyl (meth) acrylamide.

Other vinyl monomers copolymerizable with N, N-dialkylaminopropyl (meth) acrylamide do not substantially contain a free carboxyl group, and specifically include (meth) acrylamide and (meth) acrylamide. Examples thereof include acrylonitrile, vinyl acetate, lower alkyl (meth) acrylate, hydroxypropyl (meth) acrylate, and styrenes. Among them, when a copolymer is used, it is preferable that at least a part of the vinyl monomer is (meth) acrylamide. Therefore,
Examples of the copolymer in the present invention include N, N-dialkylaminopropyl (meth) acrylamide and (meth) acrylamide, or other two-component copolymerizable vinyl such as those exemplified above. Copolymers containing system monomers that do not substantially contain a carboxyl group are preferably used, but of course, N,
A copolymer of N-dialkylaminopropyl (meth) acrylamide and a vinyl monomer other than (meth) acrylamide as exemplified above can also be used.

In producing the polymer specified in the present invention, (meth) acrylamide can be used in a molar fraction ranging from 0 to 0.9, based on all constituent monomer units,
In addition to N, N-dialkylaminopropyl (meth) acrylamide and (meth) acrylamide, other vinyl monomers copolymerizable therewith have a molar ratio of 0 to 0.3 based on all constituent monomer units. It can be used in fractions.

The polymer used in the present invention includes a homopolymer of N, N-dialkylaminopropyl (meth) acrylamide and N, N
-Not only copolymers of dialkylaminopropyl (meth) acrylamide and other vinyl monomers, but also salts of these, are included, and the salts mentioned here may be either inorganic acid salts or organic acid salts. Such salts are formed at the amino group portion of the polymer. For example, if N, N-dialkylaminopropyl (meth) acrylamide is used in the form of a salt,
A polymer in the form of a salt is obtained.

The polymer used in the present invention is usually prepared by polymerizing N, N-dialkylaminopropyl (meth) acrylamide or a salt thereof alone in water in the presence of a polymerization initiator, or by co-polymerizing it with another vinyl monomer. It can be obtained by polymerizing. As the polymerization initiator in the polymerization reaction, those usually used in an aqueous polymerization reaction can be used, and examples thereof include hydrogen peroxide, potassium persulfate, and ammonium persulfate. The polymerization reaction is usually 20
It is carried out at a temperature of 100100 ° C., preferably 40-90 ° C. for 2-30 hours. This polymerization reaction can be performed in the presence of oxygen, but is preferably performed in an inert gas atmosphere such as nitrogen gas.

Paper is typically used as the base material of the recording material in the present invention, but other materials such as cloth, resin film, and synthetic paper can also be used.

A recording material is obtained by including the polymer specified in the present invention in such a base material or in a coating layer on the base material. When the polymer is contained in the coating layer, the polymer is present in the coating layer on the surface of the substrate, but when the polymer is contained in the substrate, It is preferred that a layer rich in this polymer be formed on the surface. Such polymers are, substrate 1 m ₂ per
It is preferable to contain in the range of 0.05 to 10 g, especially
More preferably, it is contained in the range of 0.1 to 5 g. When the content of the polymer specified in the present invention is lower than the lower limit of the above range, it is difficult to necessarily exert sufficient effects such as water resistance. Further, even if the polymer specified in the present invention is contained beyond the upper limit of the above-mentioned range, the effect is not so much increased, which is economically disadvantageous.

By containing the polymer defined in the present invention in the base material, in producing the recording material of the present invention, for example, in a papermaking process, an aqueous solution of the polymer defined in the present invention is added,
A paper-making method, a method in which the polymer specified in the present invention is added to the impregnating liquid, and a base material is immersed in the polymer and then post-treated can be employed. Above all, as in the latter, the polymer defined in the present invention is added to the impregnating liquid, and the base material is immersed in the impregnating liquid and then post-treated, so that a large amount of the polymer is present on the surface of the base material. Is preferred.

When the coating layer on the substrate contains the polymer specified in the present invention, usually, the polymer specified in the present invention is added to a coating liquid, and the coating liquid is applied on the substrate. It is manufactured by drying. In this case, as other components of the coating liquid, known inorganic pigments such as finely divided silica, clay, talc, diatomaceous earth, calcium carbonate, barium sulfate, titanium oxide, zinc oxide, satin white, and aluminum silicate Water-soluble polymers such as starch, gelatin, casein, gum arabic, sodium alginate, carboxymethylcellulose, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, polyacrylamide, synthetic rubber latex, and synthetic such as ethylene vinyl acetate emulsion Resin emulsions, furthermore, dispersants, fluorescent dyes, pH adjusters, defoamers, lubricants, preservatives, surfactants and the like can be mentioned.
Species or two or more species may be contained. Coating liquid containing a polymer defined in the present invention, known means, for example, a roll coater method, play de coater method, or an air knife coater method, a dry coating amount, usually 1 to 40 g / m ² approximately, preferably It is applied on the base in an amount of about ² to 30 g / m ² . Since the coating liquid usually contains an inorganic pigment, a water-soluble polymer and / or a synthetic resin emulsion, by coating so as to have the above-mentioned dry coating amount, the polymer specified in the present invention is 0.05 to 10 g / range of m ^2, preferably will be contained in a range of 0.1-5 g / m ^2.

<Effect of the Invention> In the recording material of the present invention obtained in this way, the ink is quickly absorbed into the inside thereof, and the fixation of the ink is fast, and a clear image is provided. The obtained image is excellent in water resistance and light resistance, so that this recording material is suitable for inkjet recording.

<Examples> Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.
The percentages and parts in the examples are by weight unless otherwise indicated.

Reference Example 1 400 g of water was charged and the temperature was raised to 80 ° C. Add 3 g of ammonium persulfate and add dimethylaminopropylacrylamide
A mixture of 312 g (2.0 mol), 190 g of acetic acid and 130 g of water was added dropwise over 5 hours, and the mixture was kept at the same temperature for 3 hours. During the incubation, add 2 g of ammonium persulfate. The aqueous polymer solution obtained after the completion of the polymerization reaction had a non-volatile content of 42% (polymer content of 30%), a pH of 5.8, and a viscosity of 6.4 poise (25 ° C.). This aqueous solution is referred to as a polymer aqueous solution A, and the polymer therein is referred to as a polymer A.

Reference Example 2 200 g of water was charged and the temperature was raised to 80 ° C. Add 3 g of ammonium persulfate and add dimethylaminopropylacrylamide
A mixture of 250 g (1.6 mol), 160 g of acetic acid, 57 g (0.4 mol) of a 50% aqueous acrylamide solution and 256 g of water is added dropwise over 5 hours, and the mixture is kept at the same temperature for 3 hours. During the incubation, add 2 g of ammonium persulfate. The aqueous polymer solution obtained after the completion of the polymerization reaction had a nonvolatile content of 41% (polymer content of 30%).
%), PH 4.8, and viscosity 20 poise (25 ° C.). This aqueous solution is referred to as a polymer aqueous solution B, and the polymer therein is referred to as a polymer B.

Reference Example 3 200 g of water was charged and the temperature was raised to 80 ° C. Add 5 g of ammonium persulfate and add dimethylaminopropylacrylamide
78 g (0.5 mol), acetic acid 50 g, 50% acrylamide aqueous solution 1
A mixture of 42 g (1.0 mol) and 20 g of water was dropped in 5 hours,
Further, it is kept at the same temperature for 3 hours. During the incubation, add 2 g of ammonium persulfate. The polymer aqueous solution obtained after the completion of the polymerization reaction had a non-volatile content of 37% (polymer content of 30%) and a pH of 37%.
4.6, viscosity was 43 poise (25 ° C.). This aqueous solution is referred to as a polymer aqueous solution C, and the polymer therein is referred to as a polymer C.

Example 1 A coating composition was prepared using the aqueous polymer solution A with the following composition.

Fine powdered silicic acid 100 parts Polyvinyl alcohol 50 parts Polymer aqueous solution 15 parts Water 610 parts General-purpose high-quality paper (basis weight 55 g / m ² ) with a Stöckigt sizing degree of 10 seconds is used as a base material. The working composition was applied using a wire rod so that the dry coating amount was 10 g / m ² , dried at 120 ° C. for 2 minutes, and further heat-treated at 110 ° C. for 1 minute using a hot press. Thus, a recording material was obtained. Ink jet recording was performed on this recording material using a color image printer model IO-0700 manufactured by Sharp Corporation, and the recording characteristics were evaluated. The results are shown in Table 1.

 In addition, each characteristic was evaluated as follows.

Initial color development: Measured with a Macbeth densitometer (RD-915).

Water resistance: The recorded sample was immersed in running water at 25 ° C. for 15 minutes, and the density was measured with a Macbeth densitometer.

Light fastness: Put the sample after recording into the fade meter,
After light irradiation at 60 ° C. for 40 minutes, the concentration was measured with a Macbeth densitometer.

Examples 2 and 3 Recording materials were prepared in the same manner as in Example 1 except that the aqueous polymer solution B or C was used instead of the aqueous polymer solution A. The recording characteristics of each of them were evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1 A recording material was prepared in the same manner as in Example 1, except that the aqueous polymer solution A was not added to the coating composition. The recording characteristics of this recording material were evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 2 A recording material was prepared in the same manner as in Example 1 except that polyethylene imine was used instead of Polymer A. The recording characteristics of this recording material were evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Examples 4-6 Each polymer was prepared using polymer aqueous solutions A, B and C.
% Aqueous solution, dipped in a general high-quality paper (basis weight 60 g / m ² ) having a degree of steroid size of 0 seconds, and dried to obtain about 0.8% by weight of polymer A, polymer B or A recording material containing polymer C was prepared. Each recording material was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 3 A recording material was prepared in the same manner as in Example 4, except that polyethylene imine was used instead of polymer A. This recording material was evaluated in the same manner as in Example 1, and the results were tabulated.
2 is shown.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B41M 5/00 D21H 1/34

Claims (2)

(57) [Claims] 1. A coating layer provided in or on a substrate, wherein N, N
A polymer of dialkylaminopropyl (meth) acrylamide, a copolymer of N, N-dialkylaminopropyl (meth) acrylamide with another vinyl monomer copolymerizable therewith and having substantially no carboxyl group; polymer, and a polymer selected from a salt of any of these, the recording material characterized by containing those no end to C ₆ or higher alkyl groups of the polymer molecule. 2. The composition according to claim 1, wherein the component contained in the coating layer provided in or on the substrate is N, N-dialkylaminopropyl (meth).
A copolymer of acrylamide or a salt thereof, wherein at least a part of another vinyl monomer copolymerizable with N, N-dialkylaminopropyl (meth) acrylamide constituting the copolymer is (meth) acrylamide. Yes,
Copolymer or a recording material according to claim 1, wherein the C ₆ or higher alkyl group is not present in the molecular end of the salts thereof.