JP6776825B2 - Ink set, recording method - Google Patents

Description

The present invention relates to an ink set and a recording method.

The inkjet recording method is a relatively simple device capable of recording high-definition images, and is rapidly developing in various fields. Among them, various studies have been made on obtaining more stable and high-quality recorded materials.

For example, Patent Document 1 describes a water-soluble ink for the purpose of providing an ink, an inkjet recording method, and a recorded material in which the coloring material is not scraped even if the recording portion is rubbed when the image is formed by the two-component system. A water-soluble ink used together with a reaction solution containing a reactive component that agglomerates or gels the ink by reacting with the water-soluble ink, which is at least different in hydrophilicity from water, a water-soluble organic solvent, and a pigment. An ink containing two or more types of water-soluble polymer compounds, in which at least one of the polymer compounds has a coagulation value of twice or more that of other polymer compounds and further has film-forming properties. , Ink recording methods and recorded materials are disclosed.

Japanese Unexamined Patent Publication No. 2006-160850

When a reaction solution and an ink composition as disclosed in Patent Document 1 are adhered to a recording medium to form a recorded product, the abrasion resistance may not be sufficient. That is, the "cohesive value" described in Patent Document 1 is for determining the cohesiveness after mixing the reaction solution and the high molecular polymer and leaving it for 60 minutes, and the reaction solution and the ink composition come into contact with each other. It is different from the reactivity within the reaction time required for immobilization. Further, since the "aggregation value" is also affected by the structure, particle size, etc. of the particles after the reaction, the correlation between the "aggregation value" and the above reactivity is low. Therefore, even if this "coagulation value" is doubled or more, it is difficult to secure the abrasion resistance at a more excellent level. Further, in the ejection head for ejecting the inkjet composition, the water content in the ink composition volatilizes, and among the water-soluble polymer compounds contained in the ink composition, those having higher hydrophobicity are easily dissolved or formed into a film. In some cases, the discharge head may be clogged due to the above.

Therefore, the present invention has been made to solve at least a part of the above-mentioned problems, and is excellent in abrasion resistance when the coagulant and the ink composition are adhered to the recording medium to improve the image quality. The purpose is to provide an ink set.

As a result of diligent studies to solve the above problems, the present inventors have one or more kinds of ink compositions containing resin and wax in the same or different ink compositions, and a coagulant. We have found that by using an ink set in which the cohesiveness of the resin is larger than that of the wax, the coagulant and the ink composition are adhered to the recording medium to improve the image quality, and the scratch resistance is excellent. The invention was completed. Furthermore, the present invention has been completed by finding that it is excellent in abrasion resistance and glossiness.

That is, the present invention is a cohesive liquid containing one or more ink compositions containing resin and wax in the same or separate ink compositions and a cohesive agent capable of coagulating the ink compositions. And, the cohesiveness of the resin is larger than the cohesiveness of the wax. The factors by which such an ink set can solve the problem of the present invention are considered as follows. However, the factors are not limited to this. That is, the resin has a higher cohesiveness than the wax, and after the cohesive liquid and the ink composition (hereinafter referred to as “ink composition”) adhere to the recording medium, the resin adheres to the ink composition or the like. The resin and the coagulant in the coagulating liquid aggregate and settle on the recording medium side. The precipitated agglomerated component improves the bonding force between the coating film and the recording medium by the ink composition in the recorded material, so that the recorded material has excellent scratch resistance. On the other hand, the wax has a smaller cohesiveness than the resin, and exists on the surface side (opposite to the recording medium side) of the adhered ink composition or the like after the ink composition or the like adheres to the recording medium. .. The wax present on the surface side forms a uniform film on the surface side of the ink composition or the like, so that the recorded material has excellent abrasion resistance and glossiness. Further, due to the presence of a relatively small amount of wax on the recording medium side of the adhered ink composition or the like, coagulation and sedimentation including the wax occurs, and as a result, the coating film and the recording medium due to the ink composition The binding force is improved as compared with the case of resin alone. On the other hand, the film-forming property of the ink composition or the like is further enhanced due to the presence of a relatively small amount of the resin on the surface side of the adhered ink composition or the like.

Further, the ink set of the present invention is one or more of the above-mentioned ink compositions selected from the group consisting of a colored ink composition further containing a coloring material and a clear ink composition containing substantially no coloring material. It is preferable to have a substance, and it is more preferable to have the colored ink composition and the clear ink composition, the colored ink composition contains the resin, and the clear ink composition contains the wax. It is more preferable that the coloring material having at least the coloring ink composition and the coloring material in the coloring ink composition contains one or more pigments selected from the group consisting of self-dispersing pigments and resin-dispersed pigments. The resin is preferably two or more kinds of resins having different cohesiveness, and the resin and the wax have the following relational expression (1):
0.1 mL ≤ (WJ) ≤ 3.0 mL (1)
(In the formula, J indicates the required amount of resin agglutination (mL), and W indicates the required amount of wax agglutination (mL).)
The aggregating agent is preferably one or more selected from the group consisting of organic acids, polyvalent metal salts, and cationic compounds, and the ink composition is used in an inkjet method. It is preferable that the ink composition contains 0.5% by mass or more and 15% by mass or less of the resin and the wax independently in terms of solid content with respect to the total amount of the ink composition.

Further, the recording method of the present invention includes an ink composition adhering step of adhering the ink composition contained in the ink set to the recording medium, and adhering the coagulant to the recording medium. The ink composition further includes a step, and the ink composition is preferably a colored ink composition and a clear ink composition, and the ink composition adhesion step is preferably a wet-on-wet adhesion step. Further, in the ink set of the present invention, it is preferable that the cohesiveness of the resin contained in the ink composition as a weighted average is larger than the cohesiveness of the wax contained in the ink composition as a weighted average.

It is a side view which shows the whole outline of the example of the inkjet recording apparatus which can be used in this embodiment.

Hereinafter, embodiments of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings as necessary, but the present invention is not limited thereto, and a gist thereof. Various deformations are possible within the range that does not deviate from. In the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted. Further, unless otherwise specified, the positional relationship such as up, down, left, and right shall be based on the positional relationship shown in the drawings. Furthermore, the dimensional ratios in the drawings are not limited to the ratios shown.

[Ink set]
The ink set of the present embodiment contains one or more ink compositions containing the resin and wax in the same or separate ink compositions, and a flocculant capable of coagulating the ink compositions. It has a coagulating liquid. Further, the cohesiveness of the resin is larger than that of the wax. The ink set of the present embodiment is excellent in glossiness and image quality (betamura) in addition to scratch resistance when the coagulant and the ink composition are adhered to the recording medium.

[Ink composition]
The ink set of the present embodiment has one or more ink compositions, and the same ink composition may contain resin and wax, and one ink composition is used as a separate ink composition. Ink composition may contain a resin and another ink composition may contain wax. In addition, the ink composition may contain a coloring material, a surfactant, a solvent, water and other components, if necessary. Further, the ink composition is preferably a water-based ink composition in which the resin is dispersed in water. By using such an ink composition, the scratch resistance of the obtained recorded material tends to be further improved.

In the present embodiment, the ink set preferably has one or more ink compositions selected from the group consisting of colored ink compositions and clear ink compositions. Here, an ink composition further containing a coloring material is referred to as a "colored ink composition", and an ink composition substantially containing no coloring material is referred to as a "clear ink composition". Here, "substantially free" means that the content of the coloring material is 0.10% by mass or less with respect to the total amount (100% by mass) of the ink composition. Hereinafter, when the colored ink composition and the clear ink composition are not distinguished, they are simply referred to as "ink composition". The clear ink of the present embodiment is not used for coloring the recording medium, but is used for quality such as abrasion resistance and glossiness of the recorded material, and may contain a coloring material. The content of the coloring material is preferably 0.1% by mass or less, more preferably 0.05% by mass or less.

It is preferable that the ink set has a colored ink composition and a clear ink composition, the colored ink composition contains a resin, and the clear ink composition contains wax.
As a result, by adhering the colored ink composition to the recording medium first and then the clear ink composition, the resin to be aggregated and settled tends to settle more easily on the recording medium side, and the ink composition There is a tendency for wax to be more likely to be present on the surface side of the ink.

<Resin, wax>
The ink composition of this embodiment contains a resin and a wax. Here, the resin can form a film by containing the ink composition when it is heated on the recording medium. Further, when the ink composition is heated on the recording medium, the wax cannot form a film due to the inclusion of the wax. Whether or not the film can be formed is not particularly limited, but its molecular weight, melting point, or glass transition temperature can be used as an index. For example, the resin has a molecular weight of 10,000 or more, preferably 30,000 or more, and more preferably 50,000 or more and has a weight average molecular weight of about tens of thousands. The upper limit is preferably 100,000 or less. On the other hand, the wax has a molecular weight of less than 10,000, preferably 8,000 or less, further 6,000 or less, and even more 4,000 or less, and has a weight average molecular weight of about several thousand. The lower limit is preferably 1,000 or more. As a method for distinguishing between resin and wax, it may be distinguished by the above molecular weight.
Here, the "resin" refers to a substance which is composed of a natural or synthetic polymer, preferably a synthetic polymer, and exhibits plasticity under a certain state. Further, the "wax" refers to an ester wax, a paraffin wax, an olefin wax or a mixture thereof of a higher fatty acid and a higher monohydric alcohol or a dihydric alcohol (preferably a monohydric alcohol).

In this embodiment, the cohesiveness of the resin is greater than the cohesiveness of the wax. Here, "cohesiveness" is an index indicating the cohesiveness with the cohesive agent contained in the cohesive liquid, and is the minimum required resin or wax for causing cohesive sedimentation with the cohesive agent in the solvent. Measured as the amount added. The smaller the amount added (hereinafter, also referred to as "necessary amount of cohesion (mL)"), the greater the cohesiveness.

When the resin or wax is one type or two or more types, the weighted average may be calculated from the content thereof to obtain the required agglomeration amount (mL) of each of the resin or wax, in which case they are the same or different. It shows the cohesiveness as a weighted average of all the resins contained in the ink of. It is preferable that this is larger than the cohesiveness as a weighted average of all the waxes contained in the same or different inks, because the effect of the present embodiment is particularly excellent. The weighted average is the required amount of agglomeration weighted and averaged by the mass of each resin with respect to the total mass of all the resins contained in the same or different ink compositions. The same applies to wax.

Specifically, the cohesiveness is measured by the method described in Examples described later. Specifically, an aqueous medium solution (aqueous solution or aqueous dispersion) having a resin or wax content of 0.5% by mass is prepared. Alternatively, if other components contained in the ink do not interfere with the confirmation of the cohesiveness of the resin or wax, the ink composition containing the resin or wax is mixed with water so that the content of the resin or wax becomes the above value. A sample solution of the diluted ink composition may be prepared. 0.1 mL of a 0.1 M calcium acetate aqueous solution is added dropwise to these 3.0 mL, and it is determined whether or not coagulation sedimentation occurs within 30 seconds. After that, the determination of dropping was repeated with a dropping amount of 0.1 mL until cohesive sedimentation occurred within 30 seconds (the total amount dropped was increased in 0.1 mL increments), and the minimum dropping amount at which cohesive sedimentation occurred was determined. The required amount of cohesion (mL) was used as an index of cohesiveness. The larger the cohesiveness of the resin or wax, the smaller the cohesiveness requirement (mL) required for cohesion, and the smaller the cohesiveness of the resin or wax, the larger the cohesiveness required amount (mL) required. Visually check whether coagulation sedimentation has occurred. Here, a 0.1 M aqueous solution of calcium acetate is used to confirm the cohesiveness, and it is known that calcium acetate has a function of coagulating the components of the ink composition well as a coagulant which is a polyvalent metal salt. It is also easily available and is used as an index of the cohesiveness of resins and waxes. In this embodiment, the cohesiveness is an index showing the magnitude relationship between the cohesiveness of the resin and the wax. On the other hand, the coagulant used as the coagulant of the present embodiment is not limited to calcium acetate, and may be any one described later. If the cohesive agent used is the one described later and the cohesive liquid is the cohesive liquid described later, the magnitude relationship between the cohesiveness of the resin and the wax tends to be the same, and the effect of the present embodiment can be achieved.

In the ink composition, the cohesiveness of the resin is larger than the cohesiveness of the wax, so that when the cohesive liquid and the ink composition are adhered to the recording medium, the cohesiveness and glossiness are excellent, and the image quality is high. It is also excellent in (suppression of betamura). This factor is inferred as follows. However, the factors are not limited to this. That is, the resin of the present embodiment has a large cohesive property as compared with wax, and after the ink composition or the like adheres to the recording medium, the resin and the cohesive agent in the coagulating liquid are attached to the adhered ink composition or the like. It aggregates and settles on the recording medium side. Due to the fact that the precipitated agglomerated components are fused and coalesced with each other, the strength of the coating film is improved, and the bonding force between the coating film and the recording medium by the ink composition in the recorded material is improved. Therefore, the recorded material has excellent abrasion resistance. On the other hand, the wax of the present embodiment has a smaller cohesiveness than the resin, and after the ink composition or the like adheres to the recording medium, the surface side of the adhered ink composition or the like (the side opposite to the recording medium side). ) Will increase. Due to the fact that the wax present on the surface side is present in a relatively high concentration on the surface side of the ink composition or the like, the recorded material is excellent in abrasion resistance and glossiness. Further, due to the presence of a relatively small amount of wax on the recording medium side such as the adhered ink composition, coagulation and sedimentation including the wax occurs, and as a result, phase separation in the coating film is suppressed and the coating film is applied. The film strength is improved. In addition, the bonding force between the coating film and the recording medium by the ink composition is improved as compared with the case where only the resin is used. On the other hand, the film-forming property of the ink composition or the like is further enhanced due to the presence of a relatively small amount of the resin on the surface side of the adhered ink composition or the like. The required amount of agglutination of the resin or wax is independent and not limited, but is preferably 0.1 to 3.0 mL, more preferably 0.2 to 1.0 mL, and even more preferably. It is 0.3 to 0.6 mL.

Note that Betamura means that when the ink is adhered so that the ground of the recording medium is entirely covered with the ink in the region to which the ink is adhered, unevenness of the ink density occurs in the region.

The resin and the wax may be contained in the same or different ink compositions, and may be two or more kinds of resin and two or more kinds of wax. The ink composition of the present embodiment has a relationship that among the resin and wax contained in the same or different ink composition, any one of the resin and any one of the wax have a higher cohesiveness than the wax. It suffices if the relationship can be satisfied (relationship 1). Two or more kinds of resins and / or waxes satisfying the relationship 1 may be contained.

The resin and wax may be included in the same or different ink compositions, and one kind of resin and one wax satisfying the above relationship 1 may be included, but in addition, those not satisfying relationship 1 are also included. You can go out. Preferably, in either the resin and the wax contained in the same or different ink composition, the resin capable of satisfying the relationship 1 is 50% by mass or more of the total mass of all the resins contained in the same or different ink composition. The waxes capable of satisfying Relationship 1 are 50% by mass or more of the total mass of all waxes contained in the same or different ink compositions.

From the viewpoint of further enhancing the abrasion resistance, glossiness and film forming property, the resin and wax preferably satisfy the following relational expression (1).
0.1 mL ≤ (WJ) ≤ 3.0 mL (1)
In the formula, J indicates the required amount of resin to aggregate (mL), and W indicates the required amount of wax to aggregate (mL). The formula (1) is, in other words, the difference in cohesiveness between the resin and the wax.

From the viewpoint of further enhancing scratch resistance, glossiness and film forming property, (WJ) in the formula (1) is more preferably 0.1 mL or more and 1.0 mL or less, and further preferably 0.1 mL or more and 0. .5 mL or less.
It is also preferable that the difference in the required amount of agglutination as a weighted average of the above-mentioned resin or wax satisfies the above-mentioned relationship.

The resin is preferably two or more kinds of resins having different cohesiveness. As a result, the resin that tends to coagulate and settle tends to settle more easily on the recording medium side, followed by the resin that is relatively difficult to coagulate and settle, and then the wax, which is attached to the recording medium side such as the ink composition. It is preferable because a layer is formed from the surface toward the surface side and the abrasion resistance is excellent due to the large bonding force between the layers. More preferably, the difference between the required amount of agglutination of one type of resin and the required amount of agglutination of another type of resin is 0.1 mL or more. One type of ink composition may contain the above two or more kinds of resins, or each of the two or more kinds of ink compositions may contain at least one kind of the above two or more kinds of resins. Good. The above difference is not limited, but 0.5 mL or less is preferable. When two or more types of wax are contained, it is also preferable that the difference between the required amount of agglutination of one type of wax and the required amount of agglutination of another type of wax is within the above range.

The case where each of the two or more kinds of ink compositions contains at least one of the above two or more kinds of resins is not particularly limited, but the cohesiveness of the resins contained in the colored ink composition is the clear ink composition. It is preferable that it is larger than the cohesiveness of the resin contained in the product. As a result, by adhering the colored ink composition to the recording medium first and then the clear ink composition, the resin that tends to aggregate and settle in the colored ink composition tends to settle on the recording medium side. There is a tendency, and then a resin that is relatively difficult to coagulate and settle in the clear ink composition, and then wax, in that order, can form a layer from the recording medium side to the surface side of the adhered ink composition, etc. It is preferable because it is superior in rubbing property.

The resin is not particularly limited, and examples thereof include (meth) acrylic resin, urethane resin, polyether resin, and polyester resin. Among these, the resin is preferably a (meth) acrylic resin.
On the other hand, the wax is preferably a polyolefin resin and a paraffin resin. Further, the resin and wax are preferably in the form of fine particles. In particular, the resin and wax are preferably contained in the form of an emulsion. Examples of the resin fine particles include polyester-based resin fine particles (for example, product name "Byronal MD-1500" manufactured by Toyobo Co., Ltd.), polyethylene-based resin fine particles (for example, product name "Zyxen A" manufactured by Sumitomo Seika Co., Ltd.), and urethane. Examples thereof include based resin fine particles (for example, product name “Resamine D4200” manufactured by Dainichi Seika Kogyo Co., Ltd.). By including such resin fine particles, the amount of coagulated liquid used can be reduced, and stickiness, stickiness, and bleeding on the recording surface can be further suppressed. The resin and wax may be used alone or in combination of two or more. Examples of each resin and wax will be described below.

Examples of the (meth) acrylic resin include acrylic resin emulsions. The acrylic resin emulsion is not particularly limited, and for example, a polymerized (meth) acrylic monomer such as (meth) acrylic acid and (meth) acrylic acid ester, and a (meth) acrylic monomer. And other monomers are copolymerized with each other. These commercially available products are not particularly limited, but for example, Movinyl 966A, 972, 8055A (trade name manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), Microgel E-1002, Microgel E. -5002 (trade name, manufactured by Nippon Paint Co., Ltd), Boncoat 4001, Boncoat 5454 (trade name, manufactured by DIC), SAE1014 (trade name, manufactured by Zeon Corporation) , Cybinol SK-200 (trade name, manufactured by SAIDEN CHEMICAL INDUSTRY CO., LTD.), John Krill 7100, John Krill 390, John Krill 711, John Krill 511, John Krill 7001, John Krill 632, John Krill 741, John Krill 450, John Krill 840, John Krill 62J, John Krill 74J, John Krill HRC-1645J, John Krill 734, John Krill 852, John Krill 7600, John Krill 775, John Krill 537J, John Krill 1535, John Krill PDX-7630A, John Krill 352J, John Krill 352D, John Krill PDX-7145, John Krill 538J, John Krill 7640, John Krill 7641, John Krill 631, John Krill 790, John Krill 780, John Krill 7610 (trade names above) , BASF), and NK binder R-5HN (trade name manufactured by Shin-Nakamura Chemical Co., Ltd., solid content 44%). In addition, in this specification, "(meth) acrylic" is a concept including both "methacryl" and "acrylic".

Among these, as the resin, at least one selected from the group consisting of (meth) acrylic resin and styrene- (meth) acrylic acid copolymer resin is preferable, and acrylic resin and styrene-acrylic acid copolymer system are preferable. At least one selected from the group consisting of resins is more preferable, and a styrene-acrylic acid copolymer resin is even more preferable. The above-mentioned copolymer may be in any form of a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer. As the wax, at least one selected from a polyolefin resin and a paraffin resin is more preferable, and a polyolefin resin is further preferable.

Examples of the urethane resin include urethane resin emulsions. The urethane resin emulsion is not particularly limited as long as it is a resin emulsion having a urethane bond in the molecule. For example, a polyether type urethane resin having an ether bond in the main chain, a polyester type urethane resin having an ester bond in the main chain, and the like. And a polycarbonate type urethane resin containing a carbonate bond in the main chain can be mentioned. The commercially available urethane resin emulsion is not particularly limited, but for example, Sancure 2710 (trade name manufactured by The Lubrizol Corporation), Permarin UA-150 (Sanyo Chemical Industries, Ltd.) (Product name), Superflex 460, 470, 610, 700, 860 (above, product name manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), NeoRez R-9660, R- 9637, R-940 (above, product name manufactured by Kusumoto Chemicals, Ltd.), Adeka Bontiter HUX-380, 290K (above, product name manufactured by Adeka), Takelac (registered trademark) W -605, W-635, WS-6021 (above, Mitsui Chemicals, Inc. product name) and polyether (TAISEI FINECHEMICAL CO, .LTD product name, Tg = 20 ° C) Can be mentioned.

The polyolefin wax is not particularly limited, but for example, Chemipearl S120, S650, S75N (product name manufactured by Mitsui Chemicals, Inc.), AQUACER501, AQUACER506, AQUACER513, AQUACER515, AQUACER526, AQUACER593, AQUACER582 (product name) Can be mentioned.

The paraffin wax is not particularly limited, and examples thereof include AQUACER497, AQUACER539, (product name manufactured by BYK).

The polyester-based resin is not particularly limited, and examples thereof include polybutylene terephthalate, polytrimethylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, copolymers thereof, and fine particles thereof. A sulfopolyester resin (polysulfoester resin) substituted with a sulfo group (sulfonic acid group) can also be preferably used as a polyester-based resin.
The polyether resin may be any resin having a polyether skeleton.

The resin or wax preferably has a functional group selected from the group consisting of a carboxyl group, a sulfonic acid group, an amino group, and salts thereof. Among these, resins and waxes preferably have a carboxyl group or a base thereof. By using such a resin or wax, the dispersion stability of the resin or wax tends to be further improved. Further, in particular, when the resin or wax has a carboxyl group or a base thereof, the cohesiveness of the resin or wax and the coagulant can be ensured, and the betamura or the ruled line ball of the obtained recorded material tends to be further suppressed. It is in. Further, from the viewpoint of improving the dispersion stability, a resin having an anionic functional group is preferable as the resin and the wax.

The cohesiveness of the resin or wax tends to increase as the number of the above-mentioned functional groups per unit mass of the resin or wax increases. By designing the resin or wax by controlling the number of functional groups, the cohesiveness tends to increase. Can be adjusted. In this case, since the acid value of the resin or wax tends to increase as the number of functional groups increases, it can be said that the higher the acid value of the resin or wax, the higher the cohesiveness.
Further, when the resin or wax is a fine particle such as an emulsion form and an emulsifier used for dispersing the resin or wax is used, the larger the content of the emulsifier with respect to the unit mass of the resin or wax, the lower the cohesiveness. Therefore, the cohesiveness can be adjusted depending on the presence / absence and content of the emulsifier.

In this way, the cohesiveness of the resin or wax may be designed, confirmed by the above-mentioned cohesiveness confirmation method, fed back, and redesigned to adjust to the target cohesiveness.

The glass transition point (Tg) of the resin is preferably −35 ° C. or higher, more preferably 0 ° C. or higher, still more preferably 20 ° C. or higher, even more preferably 35 ° C. or higher, and even more preferably. Is 40 ° C. or higher. The glass transition point of the resin is preferably 70 ° C. or lower, more preferably 60 ° C. or lower. Tg can be changed, for example, by changing the type and composition ratio of the monomer used for the polymerization of the resin and the wax, the polymerization conditions, and at least one kind of modification of the resin. For example, the glass transition point can be adjusted by reducing the number of polymerizable functional groups, lowering the crosslink density of the resin, or using a monomer having a relatively large molecular weight (a monomer having a large number of carbon atoms). .. The polymerization conditions include the temperature at the time of polymerization, the type of the medium containing the monomer, the concentration of the monomer in the medium, and the type and amount of the polymerization initiator and catalyst used at the time of polymerization. The glass transition point of the resin can be measured by the differential scanning calorimetry (DSC method) based on JIS K7121.

The melting point of the wax is preferably 50 ° C. or higher and 200 ° C. or higher from the viewpoint of suppressing the wax from melting too much and deteriorating its performance during heating in the ink composition adhesion step of the recording method described later and drying after the step. It is ℃ or less, more preferably 70 ℃ or more and 180 ℃ or less, and further preferably 90 ℃ or more and 180 ℃ or less.

The ink composition preferably contains the resin and the wax independently of 0.5% by mass or more and 15% by mass or less in terms of solid content with respect to the total amount (100% by mass) of the ink composition. When the resin content is within the above range, the abrasion resistance tends to be further improved, and when the wax content is within the above range, a film in the ink composition can be formed more uniformly, and the resistance can be improved. The rubbing property and glossiness tend to be further improved.

The contents of the resin and the wax are each independently, more preferably 0.7% by mass or more and 10% by mass or less in terms of solid content with respect to the total amount (100% by mass) of the ink composition, and further preferably. It is 1.0% by mass or more and 5.0% by mass or less. Further, the resin is particularly preferably 2.0% by mass or more, and the wax is particularly preferably 2.0% by mass or less.
Further, it is more preferable that the contents of the resin and the wax capable of satisfying the above-mentioned relationship 1 are independently in the above range with respect to the total amount (100% by mass) of the ink composition.

<Color material>
As the coloring material, a pigment can be used. The pigment is not particularly limited, and examples thereof include the following pigments.

The carbon black used for the black ink is not particularly limited, but for example, No. 2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, No. 2200B, etc. (above, manufactured by Mitsubishi Chemical Corporation), Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700, etc. (above, Columbia Carbon (Carbon Colomb)) Rega1 330R, Rega1 660R, Mogul L, Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc. (Cabot Corporation (CABOTC) , Color Black FW2, Color Black FW2V, Color Black FW18, Color Black FW200, Color B1ack S150, Color Black S160, Color Black Black S170, Color Black Mitsubishi Examples thereof include Black 4A and Special Black 4 (all manufactured by Degussa).

The pigment used in the white ink is not particularly limited, but for example, C.I. I. Pigment White 6, 18, 21, titanium oxide, zinc oxide, zinc sulfide, antimony oxide, zirconium oxide, white hollow resin particles and polymer particles.

The pigment used for the yellow ink is not particularly limited, but for example, C.I. I. Pigment Yellow 1,2,3,4,5,6,7,10,11,12,13,14,16,17,24,34,35,37,53,55,65,73,74,75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 167, 172, 180 can be mentioned.

The pigment used in the magenta ink is not particularly limited, but for example, C.I. I. Pigment Red 1,2,3,4,5,6,7,8,9,10,11,12,14,15,16,17,18,19,21,22,23,30,31,32, 37, 38, 40, 41, 42, 48: 2, 48: 5, 57: 1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168, 170, 171 and 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, or C.I. I. Pigment Violet 19, 23, 32, 33, 36, 38, 43, 50.

The pigment used for the cyan ink is not particularly limited, but for example, C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15:34, 15: 4, 16, 18, 22, 25, 60, 65, 66, C.I. I. Bat blue 4, 60 can be mentioned.

The pigments other than the above are not particularly limited, but for example, C.I. I. Pigment Green 7, 10, C.I. I. Pigment Brown 3, 5, 25, 26, C.I. I. Pigment Orange 1,2,5,7,13,14,15,16,24,34,36,38,40,43,63.

In an ink set having at least a colored ink composition, it is preferable that the coloring material in the colored ink composition contains one or more pigments selected from the group consisting of self-dispersing pigments and resin-dispersed pigments. As a result, the coloring material is uniformly dispersed in the recorded material, so that the glossiness tends to be excellent.

Moreover, the pigment of this embodiment may be a self-dispersion type pigment and / or a polymer dispersion type pigment.

The self-dispersing pigment is a pigment having a hydrophilic group on its surface. Hydrophilic groups include -OM, -COOM, -CO-, -SO ₃ M, -SO ₂ M, -SO ₂ NH ₂ , -RSO ₂ M, -PO ₃ HM, -PO ₃ M ₂ , -SO ₂ It is preferably at least one hydrophilic group selected from the group consisting of NHCOR, -NH ₃ , and -NR ₃ .

In these chemical formulas, M represents a hydrogen atom, an alkali metal, ammonium, a phenyl group which may have a substituent, or an organic ammonium, and R is an alkyl group or a substituent having 1 to 12 carbon atoms. Represents a naphthyl group which may have a group. Further, the above M and R are selected independently of each other.

Specifically, the self-dispersing pigment is produced by subjecting the pigment to a physical treatment and / or a chemical treatment to bond (graft) the above hydrophilic groups to the surface of the pigment. Specific examples of the physical treatment include vacuum plasma treatment. In addition, specific examples of the chemical treatment include a wet oxidation method in which oxidation is carried out in water with an oxidizing agent, a method in which a carboxyl group is bonded via a phenyl group by binding p-aminobenzoic acid to the pigment surface, and the like. Be done.

The above-mentioned polymer-dispersed pigment is a pigment that can be dispersed in a liquid by a polymer. The content of the polymer with respect to the pigment can be expressed as the coverage of the polymer that coats the pigment. The coverage of the polymer is preferably 1.0% or more and 50% or less, more preferably 1.0% or more and 10% or less, and further preferably 1.0% or more and 5.0% or less. When this coverage is 1.0% or more, the dispersibility tends to be good. Further, when the coverage is 50% or less, the color development property tends to be further improved, and when it is 5.0% or less, the color development property tends to be further improved. is there.

It is preferable that 70% by mass or more of the constituent components of the polymer is a polymer obtained by copolymerizing styrene, (meth) acrylate and (meth) acrylic acid. As a result, the fixability and glossiness of the ink tend to be further improved. Further, it is more preferable that at least one of the alkyl (meth) acrylate having 1 to 24 carbon atoms and the cyclic alkyl (meth) acrylate having 3 to 24 carbon atoms is polymerized from a monomer component of 50% by mass or more. Specific examples of the monomer component include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, and hexyl (meth). Meta) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, lauryl (meth) acrylate, isobolonyl (meth) acrylate , Cetyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, tetramethylpiperidyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxy ( Examples thereof include meta) acrylate and behenyl (meth) acrylate. In addition, as other monomer components for polymerization, hydroxy (meth) acrylate having a hydroxyl group such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and diethylene glycol (meth) acrylate, urethane (meth) acrylate, and epoxy (meth). ) Acrylate and the like can also be mentioned. In addition, in this specification, "(meth) acrylate" is a concept including both "methacrylate" and "acrylate".

In the colored ink composition, the content of the coloring material is preferably 0.2% by mass or more and 10% by mass or less, and more preferably 0.5% by mass or more, based on the total amount (100% by mass) of the ink composition. It is 7.5% by mass or less, and more preferably 1.0% by mass or more and 7.5% by mass or less. When the content of the coloring material is within the above range, the color developing property tends to be further improved.

The clear ink composition is substantially free of colorants. In the clear ink composition, the content of the coloring material is 0.10% by mass or less, preferably 0.05% by mass or less, from the viewpoint of glossiness. Further, the lower limit of the content is not particularly limited and may be less than the detection limit.

<Surfactant>
The ink composition preferably contains a surfactant from the viewpoint of glossiness. The surfactant is not particularly limited, and examples thereof include an acetylene glycol-based surfactant, a fluorine-based surfactant, and a silicone-based surfactant.

The acetylene glycol-based surfactant is not particularly limited, but is 2,4,7,9-tetramethyl-5-decine-4,7-diol and 2,4,7,9-tetramethyl-5-decine-. One selected from alkylene oxide adducts of 4,7-diol and alkylene oxide adducts of 2,4-dimethyl-5-decine-4-ol and 2,4-dimethyl-5-decine-4-ol. The above is preferable. Commercially available products of acetylene glycol-based surfactants are not particularly limited, but for example, E series (trade name manufactured by Air Products Japan, Inc.) such as Orfin (registered trademark) 104 series and Orfin E1010, etc. Surfinol (registered trademark) 104, 465, 61, DF110D (trade name manufactured by Nissin Chemical Industry CO., Ltd.) can be mentioned. The acetylene glycol-based surfactant may be used alone or in combination of two or more.

The fluorine-based surfactant is not particularly limited, and is, for example, perfluoroalkyl sulfonate, perfluoroalkyl carboxylic acid salt, perfluoroalkyl phosphate, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl betaine, and the like. Perfluoroalkylamine oxide compounds can be mentioned. Commercially available products of fluorine-based surfactants are not particularly limited, but for example, S-144, S-145 (manufactured by Asahi Glass Co., Ltd.); FC-170C, FC-430, Florard-FC4430 (manufactured by Sumitomo 3M Ltd.). FSO, FSO-100, FSN, FSN-100, FS-300 (manufactured by DuPont); FT-250, 251 (manufactured by Neos Co., Ltd.). The fluorine-based surfactant may be used alone or in combination of two or more.

The silicone-based surfactant is not particularly limited, and examples thereof include polysiloxane-based compounds and polyether-modified organosiloxanes. The commercially available silicone-based surfactant is not particularly limited, but specifically, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-347, BYK. -348, BYK-349 (trade name, manufactured by Big Chemie), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF- 642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like can be mentioned. The silicone-based surfactant may be used alone or in combination of two or more.

The content of the surfactant is preferably 0.05% by mass or more and 2.5% by mass or less, and more preferably 0.1% by mass or more and 1.5% by mass, based on the total amount (100% by mass) of the ink composition. It is mass% or less. When the content of the surfactant is within the above range, the wettability of the ink composition adhered to the recording medium tends to be further improved.

<Solvent>
The ink composition may contain a solvent. The solvent is not particularly limited, but for example, an organic solvent or water can be used.

The organic solvent is not particularly limited, but for example, a hydrocarbon solvent such as toluene, hexane, cyclohexane, benzene, octane, isooctane; an ester solvent such as ethyl acetate, butyl acetate, γ-butyrolactone; acetone, methyl ethyl ketone, methyl. Ketone solvents such as isobutyl ketone and cyclohexanone; alcohol solvents such as methanol, ethanol, propanol, isopropanol, butanol, propylene glycol and 1,3-butanediol; halogen solvents such as dichloroethane and chloroform, diethyl ether, tetrahydrofuran and the like. Ether-based solvents; N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 2-pyrrolidone, N-methyl-ε-caprolactam, hexamethylphospho Examples thereof include amide solvents such as luamide, glycerin, triethylene glycol, triethylene glycol monobutyl ether, and water-soluble organic solvents.

The content of the organic solvent is preferably 0.1% by mass or more and 90% by mass or less, and more preferably 1.0% by mass or more and 50% by mass or less with respect to the total amount (100% by mass) of the ink composition. .. When the content of the organic solvent is within the above range, the wettability of the ink composition adhering to the recording medium tends to be further improved.

Examples of water include pure water such as ion-exchanged water, ultra-filtered water, reverse osmosis water, and distilled water, and ultrapure water from which ionic impurities have been removed as much as possible. Further, when water sterilized by irradiation with ultraviolet rays or addition of hydrogen peroxide or the like is used, it is possible to prevent the growth of mold and bacteria when the aggregated liquid is stored for a long period of time. This tends to further improve storage stability.

It is preferable that the ink composition and the coagulated liquid of the present embodiment are water-based compositions containing water as one of the main solvent components in terms of environmental friendliness and particularly excellent effects of the present embodiment. The content of water is preferably 40% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more, based on the total mass of the composition (aggregate liquid). The upper limit of the water content is preferably 98% by mass or less.

Other components of the ink composition include solubilizers, viscosity regulators, pH regulators, antioxidants, preservatives, fungicides, corrosion inhibitors, and chelates to capture metal ions that affect dispersion. Various additives such as an agent (for example, sodium ethylenediaminetetraacetate) can also be appropriately contained.

The ink composition is preferably used in the inkjet method described later from the viewpoint of more effectively and surely exerting the effect according to the present invention. For example, in the ink composition adhesion step in the recording method described later, the ink composition can be used to adhere to the recording medium by an inkjet method.

[Coagulant]
The coagulant of the present embodiment contains a coagulant capable of coagulating the above-mentioned ink composition. Specifically, it contains a coagulant capable of agglutinating the ink composition by agglutinating the components contained in the above-mentioned ink composition. The coagulant in the coagulant interacts with the ink composition to agglomerate the components contained in the ink composition and thicken or insolubilize the ink composition. As a result, it is possible to prevent landing interference and bleeding of the ink composition to be adhered thereafter, and it is possible to uniformly draw lines, fine images, and the like. The component that aggregates by the flocculant contained in the ink composition is at least one or both of the resin and the wax, but in addition, other components may also aggregate. Examples of other components include coloring materials. Aggregating the components contained in the above-mentioned ink composition also means reacting and aggregating the components contained in the ink composition, and the agglutinating solution is also referred to as a reaction solution.

<Coagulant>
The flocculant is not particularly limited, but is preferably one or more selected from the group consisting of organic acids, polyvalent metal salts, and cationic compounds. As a result, betamura and bleed tend to be more suppressed. Among the components contained in the ink composition, examples of the components that are agglutinated by the aggregating agent include the above-mentioned pigment, resin, and wax.

The organic acid is not particularly limited, but is preferably a carboxylic acid, and examples thereof include maleic acid, acetic acid, phosphoric acid, oxalic acid, malonic acid, and citric acid. Of these, monovalent or divalent or higher carboxylic acids are preferable. By containing such a carboxylic acid, the aggregation effect of the resin fine particles is further improved, and by extension, the color development property tends to be more excellent. The organic acid may be used alone or in combination of two or more.

The polyvalent metal salt is not particularly limited, but a polyvalent metal salt of an inorganic acid or a polyvalent metal salt of an organic acid is preferable from the viewpoint of more effectively and surely exerting the effect according to the present invention. Such polyvalent metal salts are not particularly limited, but are, for example, group 2 alkaline earth metals in the periodic table (for example, magnesium and calcium), and transition metals of the third group in the periodic table (for example, lanterns). , Earth metals from Group 13 of the Periodic Table (eg, aluminum), and salts of lanthanides (eg, neodymium). Further, as the salt of these polyvalent metals, a carboxylate (for example, formic acid, acetic acid, benzoate), a sulfate, a nitrate, a chloride, and a thiocyanate are suitable. Among them, polyvalent metal salts include calcium or magnesium salts of carboxylic acids (artic acid, acetic acid, benzoate, etc.), calcium or magnesium salts of sulfuric acid, calcium or magnesium salts of nitrate, calcium chloride, magnesium chloride, etc. And one or more selected from the group consisting of calcium salt or magnesium salt of thiocyanic acid are preferable. The polyvalent metal salt may be used alone or in combination of two or more.

The cationic compound is not particularly limited, and examples thereof include a cationic polymer, a cationic surfactant, and a water-soluble metal compound. From the viewpoint of more effectively and surely exerting the effect of the present invention, examples of the cationic polymer include polyethyleneimine, polyallylamine, polyallylamine, alkylamine polymer, JP-A-59-20696, JP-A-59-333176, and JP-A-59. 333177, 59-155088, 60-11389, 60-49990, 60-83882, 60-109894, 62-198493, 63-49478, 63-115780 No. 63-280681, Japanese Patent Application Laid-Open No. 1-4071, No. 6-234268, No. 7-125411, No. 10-193776, etc. The polymer having is preferably used. From the same viewpoint, the weight average molecular weight of these cationic polymers is preferably 5000 or more, and more preferably about 5000 to 100,000. The weight average molecular weight of the cationic polymer is measured by gel permeation chromatography using polystyrene as a standard material.
Examples of the cationic surfactant include salts of compounds having a cationic group, quaternary ammonium salts, sulfonates and the like.

The content of the coagulant is preferably 1.0% by mass or more and 20% by mass or less, more preferably 2.0% by mass or more and 17.5% by mass or less, based on the total amount of the coagulating liquid (100% by mass). It is more preferably 0.0% by mass or more and 15% by mass or less, and particularly preferably 5.0% by mass or more and 10.0% by mass or less.
The content of the flocculant is preferably 0.1 to 1 mol / L, more preferably 0.2 to 0.9 mol / L, and 0.3 to 0.3 to the total amount of the flocculant (1 L (liter)). 0.8 mol / L is more preferable. Mol / L as a unit is also described as M.
When the content of the flocculant is within the above range, betamura and bleed tend to be further suppressed.

The coagulant used in the present embodiment may contain the same surfactant, organic solvent and water as those used in the above-mentioned ink composition. In addition, the agglomerate liquid captures other components such as dissolution aids, viscosity regulators, pH regulators, antioxidants, preservatives, fungicides, corrosion inhibitors, and metal ions that affect dispersion. Various additives such as the chelating agent of the above can be appropriately added.

〔Recording method〕
The recording method of the present embodiment includes an ink composition attaching step of adhering the ink composition of the ink set of the present embodiment to the recording medium. Further, the ink composition may be a colored ink composition or a clear ink composition, further comprising a coagulating liquid adhering step of adhering the coagulating liquid to the recording medium.

[Coagulation liquid adhesion process]
The coagulating liquid adhering step is a step of adhering the coagulating liquid to the recording medium. The means for adhering the agglomerated liquid is not particularly limited, and for example, roller coating, spray coating, or an inkjet method can be used. Of these, it is preferable to attach them by an inkjet method. By adhering the agglomerate liquid by an inkjet method, there is a tendency that the surface quality change of the media is suppressed and the moisture and friction resistance is further improved.

The amount of the flocculant adhering to the recording medium is preferably 0.01 mg / inch ² or more and 1.0 mg / inch ² or less, and more preferably 0.01 mg / inch ² or more and 0.50 mg / inch in terms of solid content. ^{It is 2} or less, more preferably 0.01 mg / inch ² or more and 0.2 mg / inch ² or less. When the amount of adhesion is within the above range, the stickiness and ruled line balls of the obtained recorded matter tend to be further suppressed.

The time interval from the end of the coagulation liquid adhesion step to the start of the ink composition adhesion step is preferably 60 seconds or less, more preferably 0.10 seconds or more and 60 seconds or less, and further preferably 0.10 seconds or more. It is 30 seconds or less, and particularly preferably 0.10 seconds or more and 10 seconds or less. When the time interval from the end of the coagulating liquid adhering step to the start of the ink composition adhering step is 60 seconds or less, the reaction efficiency between the coagulating liquid and the ink composition is further improved, and the image quality of the obtained recorded matter is improved. It tends to improve. In particular, when the film thickness of the coating film formed by the ink composition is small, it is preferable that the time interval is short.

[Ink composition adhesion process]
The ink composition adhering step is a step of adhering the ink composition to the recording medium, and can be performed at the same time as or before and after the coagulant adhering step described above, but is preferably performed after the coagulant adhering step. .. The means for adhering the ink composition is not particularly limited, and for example, roller coating, spray coating, or an inkjet method can be used. Of these, it is preferable to attach them by an inkjet method. By adhering the ink composition by an inkjet method, there is a tendency that the surface quality change of the medium is suppressed and the moisture resistance and friction resistance are further improved.

The ink composition adhesion step is preferably a wet-on-wet adhesion step. Here, "wet-on-wet adhesion" is a step of adhering two or more ink compositions, and the two or more ink compositions are simultaneously adhered to the recording medium or the ink composition adhered first. With 60% by mass or more of the volatile components contained in the object remaining on the recording medium, the next ink composition is further adhered, or the recording medium is within 30 seconds after the ink composition is first adhered. At least one of the following ink compositions is started to adhere when the surface temperature of the ink is 38 ° C. or lower. By wet-on-wet adhesion, when the ink composition containing the resin and the ink composition containing the wax use different ink sets, the two or more adhered ink compositions are uniformly mixed. Due to this, the abrasion resistance tends to be further improved.

The film thickness of the dry film after drying the recording region to which the ink composition and the coagulant are attached is preferably 0.10 to 3.0 μm, more preferably 0.10 to 2.0 μm. More preferably, it is 0.10 to 1.0 μm. When the film thickness of the dry film is 0.10 μm or more, the betamura and the ruled line balls of the obtained recorded matter tend to be further suppressed. Further, when the film thickness of the dry film is 3.0 μm or less, the change in glossiness of the obtained recorded material tends to be further suppressed. Here, the "recording area" means an area on the surface of the recording medium on which an image is formed. The ruled line ball has a shape in which the outline of the ruled line is connected to each other when the ruled line is recorded.

The amount of each of the resin and wax adhering to the recording medium is independently, in terms of solid content, preferably 0.01 mg / inch ² or more, 1.0 mg / inch ² or less, and more preferably 0.01 mg. / inch ² or more 0.75 mg / inch ² or less, more preferably 0.02 mg / inch ² or more 0.6 mg / inch ² or less, still more preferably 0,05Mg / inch ² or more 0.5 mg / inch ² or less. When the amount of adhesion is 0.01 mg / inch ² or more, the betamura and the ruled line balls of the obtained recorded matter tend to be more suppressed. Further, when the amount of the resin adhered to the recording region is 0.75 mg / inch ² or less, the glossiness of the obtained recorded material tends to be more excellent.

The coating weight of the total of the resin and the wax on the recording medium is a solid content basis, preferably, 0.02 mg / inch ² or more and 2.0 mg / inch ² or less, more preferably 0.02 mg / inch ² or more 1.5 mg / inch ² or less, more preferably 0.04 mg / inch ² or more 1.2 mg / inch ² or less, still more preferably 0,1mg / inch ² or more 1.0 mg / inch ² or less Is.

[Recording medium]
Examples of the recording medium include an absorbable, low-absorbent, or non-absorbable recording medium. Among these, it is preferable that the recording medium is a low-absorption recording medium or a non-absorbable recording medium. When a low-absorption recording medium or a non-absorbent recording medium is used, the ink composition is repelled on the surface of the medium and it is difficult to apply the flocculant uniformly, so that betamla and bleeding are more likely to occur. However, in the present embodiment, it is particularly useful because the ink composition can be prevented from being repelled by the coagulating liquid. Further, when a low-absorption recording medium or a non-absorbable recording medium is used, the coagulant does not permeate the recording medium and tends to remain on the surface of the recording medium, so that the stickiness of the recording surface and the moisture resistance are deteriorated. Tend to do. However, in the present embodiment, since the amount of the coagulant used can be reduced by using the ink composition, the stickiness of the recording surface can be improved, which is particularly advantageous.

Here, the "low-absorbing recording medium" or the "non-absorbable recording medium" refers to a recording medium having a water absorption amount of 10 mL / m ² or less from the start of contact to 30 msec in the Bristow method. .. This Bristow method is the most popular method for measuring the amount of liquid absorbed in a short time, and is also adopted by the Japan Pulp and Paper Technology Association (JAPAN TAPPI). For details of the test method, refer to the standard No. of "JAPAN TAPPI Pulp and Paper Test Method 2000 Edition". It is described in 51 "Paper and Paperboard-Liquid Absorption Test Method-Bristow Method".

Further, the non-absorbent recording medium or the low-absorption recording medium can be classified according to the wettability of the recording surface with water. Specifically, 0.5 μL of water droplets are dropped on the recording surface of the recording medium, and the reduction rate of the contact angle (comparison between the contact angle at 0.5 msec and the contact angle at 5 seconds after landing) is measured. The recording medium can be characterized by. More specifically, as a property of the recording medium, the non-absorbability of the "non-absorbable recording medium" means that the above-mentioned reduction rate is less than 1%, and the low absorption of the "low absorption recording medium". Gender refers to the above-mentioned reduction rate of 1% or more and less than 5%. Further, the absorbency means that the above-mentioned reduction rate is 5% or more. The contact angle can be measured using a portable contact angle meter PCA-1 (manufactured by Kyowa Interface Science Co., Ltd.) or the like.

The absorbent recording medium is not particularly limited, but for example, plain paper such as electrophotographic paper having high permeability of the ink composition, inkjet paper (an ink absorbing layer composed of silica particles or alumina particles, or polyvinyl). Art paper used for general offset printing with relatively low permeability of ink compositions, from ink-absorbing layers composed of hydrophilic polymers such as alcohol (PVA) and polyvinylpyrrolidone (PVP). , Coated paper, cast paper, etc.

The low-absorbency recording medium is not particularly limited, and examples thereof include coated paper provided with a coating layer on the surface for receiving oil-based ink. The coated paper is not particularly limited, and examples thereof include printed paper such as art paper, coated paper, and matte paper.

The non-absorbent recording medium is not particularly limited, but for example, a plastic film having no ink absorbing layer, a medium in which plastic is coated on a base material such as paper, or a medium in which a plastic film is adhered. And so on. Examples of the plastic referred to here include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene and polypropylene.

Further, in addition to the above-mentioned recording medium, an ink non-absorbent or low-absorbency recording medium such as a plate of metals such as iron, silver, copper and aluminum, and glass can also be used.

In particular, the recording medium is preferably in the form of a roll. When recording, the roll-shaped recording medium can be used in such a manner that the head is scanned once relative to the recording medium and wound by a take-up roller. When such a recording medium is used, when all colors cannot be recorded by one feeding due to a large number of types of colored inks used and the recording is performed many times, the recording medium may be used multiple times. On the other hand, a recorded object can be obtained by scanning the head relatively once and repeating the operation of winding with the take-up roller. However, since it is in the form of a roll, the resin layer tends to have cracks. When cracks occur, the image quality of the obtained recorded material tends to deteriorate due to reasons such as the coagulation liquid permeating the cracks. However, the coating film made of the ink composition obtained by the recording method of the present embodiment is less likely to cause cracks. Therefore, the present invention is particularly useful when a recording medium having such a shape is used.

[Recording device]
Next, a recording device that can be used in the recording method of the present embodiment will be described. 1 is a side view showing an overall outline of an example of the inkjet recording device 1 that can be used in the present embodiment. As shown in FIG. 1, the inkjet recording device 1 includes a feeding unit 10 of a recording medium, a conveying unit 20, a recording unit 30, a drying device 90, and a discharging unit 70.

Of these, the drying device 90 has a first drying unit 40 that dries the coagulated liquid, and a second drying unit 50 that dries the recorded material obtained by the recording method according to the present embodiment.

Further, the feeding unit 10 is provided so that the roll-shaped recording medium F can be fed to the conveying unit 20. Specifically, the feeding unit 10 has a roll medium holder 11, and the roll medium holder 11 holds a roll-shaped recording medium F. Then, by rotating the roll-shaped recording medium F, the recording medium F can be fed to the transport unit 20 on the downstream side in the feed direction Y.

Further, the transport unit 20 is provided so that the recorded medium F sent from the feed unit 10 can be transported to the recording unit 30. Specifically, the transport unit 20 has a first feed roller 21 and is configured to be able to further transport the transmitted recording medium F to the recording unit 30 on the downstream side in the feed direction Y.

Further, the recording unit 30 is provided so that the coagulating liquid can be applied to the recording medium F sent from the transport unit 20 and the ink composition can be ejected for recording. Specifically, the recording unit 30 includes heads 31 and 32 that perform a coagulating liquid adhering step, a recording head 33 that performs an ink composition adhering step, and a platen 34 as a medium support portion. Recording may be performed by a multipath method in which recording is performed by alternately performing scanning in a direction in which the head intersects the transport direction of the recording medium and transport in the transport direction of the recording medium. .. Alternatively, recording may be performed by a single-pass system in which the position of the head is fixed during recording and recording is performed while continuously transporting the recording medium in the transport direction.

Of these, the platen 34 is provided so that the recording medium F can be supported from the back surface. Further, the platen 34 is provided with a first drying unit 40 for drying the coagulated liquid adhering to the recording medium F and the ink composition adhering to the recording medium F. Further, a second feed roller 43 is provided on the downstream side of the platen 34 in the feed direction Y. The second feed roller 43 is configured to be able to feed the recorded recording medium F to the second drying portion 50 on the downstream side of the feed direction Y.

Further, the second drying unit 50 is configured so that the coagulated liquid adhering to the recording medium F and the ink composition adhering to the recording medium F can be further dried. Further, a third feed roller 65 is provided in the vicinity of the outlet 64 of the second drying portion 50. The third feed roller 65 is arranged so as to be in contact with the back surface of the recording medium F, and is configured to be able to feed the recording medium F to the discharge unit 70 on the downstream side in the feed direction Y.

Further, the discharge unit 70 is provided so that the recording medium F sent from the second drying unit 50 can be further sent to the downstream side in the feed direction Y and discharged to the outside of the inkjet recording device 1. Specifically, the discharge unit 70 includes a fourth feed roller 71, a fifth feed roller 72, a sixth feed roller 73, a seventh feed roller 74, and a take-up roller 75. Of these, the fourth feed roller 71 and the fifth feed roller 72 are arranged so as to be in contact with the surface of the recording medium F. Further, the 6th feed roller 73 and the 7th feed roller 74 are arranged so as to form a roller pair. The recording medium F discharged by the 6th feed roller 73 and the 7th feed roller 74 is provided so as to be wound by the take-up roller 75.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

[Aggregation requirement]
The required amount of agglomeration (mL) was measured for the resins and waxes used below. Specifically, a 0.1 M aqueous calcium acetate solution is added to 3.0 mL of a sample solution of an aqueous dispersion of resin or wax prepared by diluting with water so that the content of the resin or wax is 0.5% by mass. . 1 mL was added dropwise, and it was determined whether coagulation sedimentation occurred within 30 seconds. After that, the determination of dropping was repeated with a dropping amount of 0.1 mL until cohesive sedimentation occurred within 30 seconds (the total amount dropped was increased in 0.1 mL increments), and the minimum dropping amount at which cohesive sedimentation occurred was determined. The required amount of cohesion (mL) was used as an index of cohesiveness. The larger the cohesiveness of the resin or wax, the smaller the cohesiveness requirement (mL) required for cohesion, and the smaller the cohesiveness of the resin or wax, the larger the cohesiveness required amount (mL) required. It was visually confirmed whether or not coagulation sedimentation occurred. The results obtained are shown with the following resin and wax types.

[Material for 1st or 2nd ink composition]
The main materials for the first or second ink composition used in the following examples and comparative examples are as follows.
[Pigment]
Carbon black [resin]
Chemipal S120 (trade name manufactured by Mitsui Chemicals, required amount of aggregation 0.1 mL, solid content 27% by mass)
Chemipal S75N (trade name manufactured by Mitsui Chemicals, required amount of aggregation 0.2 mL, solid content 25% by mass)
MOVIN 8055A (Product name manufactured by Nippon Synthetic Chemical Industry Co., Ltd., required agglomeration amount 0.3 mL, solid content 43% by mass)
Superflex 860 (trade name manufactured by Taiichi Kogyo Seiyaku Co., Ltd., required agglomeration amount 0.6 mL, solid content 40% by mass)
Movinyl 972 (trade name manufactured by Nippon Synthetic Chemistry Co., Ltd., required agglomeration amount 3.0 mL, solid content 50% by mass)
〔wax〕
AQUACER 526 (Product name manufactured by Big Chemie, required amount of aggregation 0.1 mL, solid content 30% by mass)
AQUACER593 (trade name manufactured by Big Chemie, required amount of aggregation 0.2 mL, solid content 30% by mass)
AQUACER 582 (trade name manufactured by Big Chemie, required amount of aggregation 0.6 mL, solid content 40% by mass)
AQUACER539 (trade name manufactured by Big Chemie, required amount of aggregation 3.0 mL, solid content 35% by mass)
[Surfactant]
BYK348 (trade name manufactured by Big Chemie, silicone-based surfactant)
Surfinol DF110D (trade name manufactured by Nissin Chemical Industry Co., Ltd.)
〔solvent〕
1,3-Butanediol Propylene Glycol 2-Pyrrolidone Water [Additive]
Triethanolamine Ethylenediaminetetraacetic acid sodium

[Preparation of first and second ink compositions]
Each material was mixed with the composition shown in Table 1 below and stirred well to obtain first and second ink compositions. In Table 1 below, the numerical value indicates the solid content, the unit of the numerical value is mass%, and the total is 100.0 mass%.

[Material for coagulant]
The main materials for the agglomerate (reaction solution) used in the following examples and comparative examples are as follows.
[Coagulant]
Magnesium sulfate [surfactant]
BYK348 (trade name manufactured by Big Chemie, silicone-based surfactant)
〔solvent〕
1,3-Butanediol Propylene Glycol 2-Pyrrolidone Water

[Preparation of coagulant]
Each material was mixed with the composition shown in Table 2 below and sufficiently stirred to obtain a coagulated liquid. In Table 2 below, the numerical value indicates the solid content, the unit of the numerical value is mass%, and the total is 100.0 mass%. In the reaction solution 1 and the reaction solution 2, the coagulant has a concentration of about 0.5 M with respect to the coagulant.

[Preparation of recorded material]
The recording medium was carried into the PX-G930 (trade name of the Epson printer), and the coagulated liquid (reaction liquid) filled in the head was inkjet with a resolution of 720 x 720 dpi and an adhesion amount of 1.7 mg / inch ^2. It was applied. Next, the first ink composition filled in the head is inkjet-coated on the coagulating liquid adhering surface at a resolution of 720 × 720 dpi and an adhering amount of 7 mg / inch ² , and further, in an example using the second ink composition, the head The second ink composition packed in the ink composition was applied to the surface to which the ink composition was adhered by inkjet at a resolution of 720 × 720 dpi and an adhesion amount of ² mg / inch ² to obtain a recorded material on a recording medium. During the coating, the surface temperature of the recording medium was adjusted to 25 ° C. An example using the second ink composition was coating by a wet-on-wet method. After the coating was applied and the recording medium was discharged from the printer, the recording medium was allowed to stand in an environment of 60 ° C. for 10 minutes to dry. Coated paper (trade name "Elitelcast 73" manufactured by Daio Paper Corporation) was used as the recording medium. Table 4 summarizes the required amount of resin and wax to be agglomerated and the required amount of weighted average agglutination contained in the ink composition used in each example.

[Image quality (Betamura)]
With respect to the recorded material produced by the same method as the above [Production of recorded material] except that a solid pattern of 10 × 10 mm is produced, the solid pattern is visually confirmed, and the image quality (image quality according to the following evaluation criteria). Bettamura) was evaluated. The results obtained are shown in Table 3.
(Evaluation criteria)
⊚: No unevenness inside the pattern (coloring by ink looks uneven) is not observed.
◯: No large non-uniformity is observed inside the pattern, but some unevenness (fine non-uniformity) is observed.
Δ: Considerable unevenness (large non-uniformity) is observed inside the pattern.

[Abrasion resistance]
The obtained recorded material is recorded by applying a load of 300 g to the friction fastness tester AB-301 (trade name manufactured by Tester Sangyo Co., Ltd.) with a white cotton cloth (JIS L 0803 compliant) attached. It was rubbed 30 times until it peeled off. Then, the peeling of the recorded material on the recording medium was visually observed, and the abrasion resistance was evaluated according to the following evaluation criteria. The results obtained are shown in Table 3.
(Evaluation criteria)
⊚: No peeling of the recorded material is observed even after rubbing 30 times.
◯: Peeling of the recorded material was observed after 20 round trips or more and 29 round trips or less.
Δ: Peeling of the recorded material was observed after 10 round trips or more and 19 round trips or less.
X: Peeling of the recorded material was observed within 9 round trips.

[Glossy]
The recorded material was measured for 60 ° gloss using a gloss measuring device GM-268Plus (trade name manufactured by Konica Minolta), and the gloss was evaluated according to the following evaluation criteria. The results obtained are shown in Table 3.
(Evaluation criteria)
⊚: 84 or more ○: 60 or more and less than 84 Δ: 45 or more and less than 60 ×: less than 45

From the evaluation results, an ink composition containing a resin and a wax having a higher cohesiveness than the wax and containing the resin and an ink composition containing the wax or an ink composition containing the resin and the wax was used to prepare a coagulating liquid. It was found that Examples 1 to 8 used were excellent in image quality and abrasion resistance.

Among them, from Examples 1 and 7, when one ink composition is used, the same ink composition contains a resin and a wax having a resin cohesiveness larger than that of the wax, so that the image quality and abrasion resistance are improved. Turned out to be excellent.

Further, from Example 8, it was found that the image quality and abrasion resistance were excellent even when the resin and the wax, which had a higher cohesiveness of the resin than the cohesiveness of the wax, were contained in another ink composition.

Further, from Examples 2 and 3, even when two ink compositions are used, one ink composition contains a resin and a wax having a resin cohesiveness larger than that of the wax cohesiveness in the same ink composition. It was found that the image quality and abrasion resistance were excellent.

Further, from Examples 4 and 5, when two ink compositions are used, the two ink compositions contain a resin and a wax having a resin cohesiveness larger than that of the wax cohesiveness in the same ink composition. It was found that the image quality and abrasion resistance were particularly excellent and the glossiness was also excellent.

Further, from Example 6, when two ink compositions are used, at least one ink composition contains a resin and a wax having a resin cohesiveness larger than that of the wax cohesiveness in the same ink composition. It was found that the image quality and abrasion resistance were excellent. Further, from the comparison between Examples 1 and 6, it is excellent in glossiness that the cohesiveness of the resin is larger than the cohesiveness of the wax as the weighted average of the resins contained in the same or different ink compositions, and the effect of the present invention is obtained. Turned out to be particularly good.

On the other hand, Comparative Examples 1 to 1 in which an ink composition containing a resin and a wax having a larger cohesiveness than the wax cohesiveness in the same or different ink compositions is not used, or a cohesive liquid is not used. No. 5 was inferior in image quality or scratch resistance.

1 ... Inkjet recording device, 10 ... Feeding unit, 11 ... Roll medium holder, 20 ... Conveying unit, 21 ... First feed roller, 30 ... Recording unit, 31 ... Head, 32 ... Head, 33 ... Recording head, 34 ... Platen, 40 ... 1st drying section, 43 ... 2nd feed roller, 50 ... 2nd drying section, 64 ... outlet, 65 ... 3rd feed roller, 70 ... discharge section, 71 ... 4th feed roller, 72 ... 5th Feed roller, 73 ... 6th feed roller, 74 ... 7th feed roller, 75 ... take-up roller, 90 ... drying device, F ... recording medium, Y ... feed direction.

Claims (13)

It has an ink composition containing a resin and an ink composition containing a wax, or an ink composition containing a resin and a wax.
It has an agglutinating liquid containing an agglutinating agent capable of agglutinating the components of the ink composition.
The resin and wax are ink sets containing the resin and wax whose cohesiveness of the resin is larger than that of the wax. The ink set according to claim 1, wherein the ink composition is either a colored ink composition or a clear ink composition, each of which further contains a coloring material. The ink composition having the resin-containing ink composition and the wax-containing ink composition, the resin-containing ink composition is the colored ink composition, and the wax-containing ink composition is the clear ink. The ink set according to claim 2, which is a composition. Having at least the colored ink composition
The ink set according to claim 2 or 3, wherein the coloring material contained in the colored ink composition contains at least one of a self-dispersing pigment and a resin-dispersed pigment. The ink set according to any one of claims 1 to 4, wherein the resin contains two or more kinds of resins having different cohesiveness from each other. The ink set according to any one of claims 1 to 5, wherein the resin and the wax satisfy the following relational expression (1).
0.1 mL ≤ (WJ) ≤ 3.0 mL (1)
(In the formula, J indicates the required amount of resin agglutination (mL), and W indicates the required amount of wax agglutination (mL).) The ink set according to any one of claims 1 to 6, wherein the flocculant is at least one of an organic acid, a polyvalent metal salt, and a cationic compound. The ink set according to any one of claims 1 to 7, wherein the ink composition is used by adhering to a recording medium by an inkjet method. The invention according to any one of claims 1 to 8, wherein each of the resin and the wax is contained in the ink composition in an amount of 0.5% by mass or more and 15% by mass or less in terms of solid content with respect to the total amount of the ink composition. Ink set. The ink set according to any one of claims 1 to 9, wherein the cohesiveness of the resin contained in the ink composition as a weighted average is larger than the cohesiveness of the wax contained in the ink composition as a weighted average. The step of adhering the ink composition of the ink set to the recording medium and the coagulation liquid of the ink set to adhere to the recording medium according to any one of claims 1 to 10. A recording method comprising an adhesion process. The recording method according to claim 11, wherein the ink composition includes an ink composition containing a wax and an ink composition containing a resin having a higher cohesiveness than the wax. The recording method according to claim 12, wherein the ink composition attaching step is a step of attaching wet-on-wet.

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