JP6024040B2 - Non-aqueous inkjet ink and ink set - Google Patents

Description

  The present invention relates to a non-aqueous inkjet ink particularly suitable for printing images, characters and the like on the surface of a polyvinyl chloride sheet, and an ink set including the non-aqueous inkjet ink.

  Conventionally, ink jet printing in which ink jet ink is ejected as fine droplets through nozzles of an ink jet printer to print images and characters has been suitably used mainly for printing on water-absorbing surfaces such as paper. As an ink jet ink suitable for printing on the surface, an aqueous ink jet ink in which a colorant such as a water-soluble dye is added to water has been widely used.

  However, in recent years, inkjet printing has come to be used for printing on various surfaces, particularly in various fields for business use. In order to print images and characters with good water quality, light resistance, friction resistance, etc. corresponding to the various surfaces, the conventional water-based inkjet ink can be used as a solvent. Non-aqueous inkjet inks that substantially contain no water and use only organic solvents, and inkjet printers using the same have been put into practical use and are becoming popular.

For example, a large-scale inkjet printer using the non-aqueous inkjet ink has been developed and used for printing images and characters on the surface of a polyvinyl chloride sheet such as tarpaulin, which is widely used as an outdoor advertising medium. It has become.
The non-aqueous inkjet ink for the large-sized inkjet printer includes a colorant such as a pigment excellent in light resistance, a binder resin for satisfactorily fixing the colorant to a surface of a polyvinyl chloride sheet, and the binder. A resin containing an organic solvent that can dissolve or disperse the resin well and can disperse the colorant is mainly used.

As the binder resin, various resins having excellent fixability to the surface of a polyvinyl chloride sheet or the like are used, and among them, a polyvinyl chloride resin having the best fixability is preferably used. As the polyvinyl chloride resin, a vinyl chloride-vinyl acetate copolymer is particularly preferably used.
Copolymerization of vinyl acetate with vinyl chloride improves the solubility in organic solvents, and improves the scratch resistance of printing by improving the flexibility of images and characters printed on the surface of polyvinyl chloride sheets. It is because it can.

Further, as organic solvents, conventionally, so-called aprotic polar organic solvents such as nitrogen-containing heterocyclic compounds such as N-methyl-2-pyrrolidone or oxygen-containing heterocyclic compounds such as lactones are used. It has been common to adjust the surface tension, viscosity, etc. of non-aqueous inkjet inks in combination with high alkylene glycol derivatives.
However, the combination of the conventional organic solvents has a problem that the storage stability of the non-aqueous inkjet ink is low, and the binder resin and the colorant are likely to aggregate or settle.

  Therefore, in Patent Document 1, while improving the storage stability of the non-aqueous inkjet ink, the fixing property of printing is enhanced, and the binder resin and the colorant are firmly fixed to the surface of a polyvinyl chloride sheet or the like, In order to print characters and images with excellent image quality, such as water resistance, light resistance, and friction resistance, it has been proposed to use the following two or more polyalkylene glycol alkyl ethers in combination.

That is, polyalkylene glycol alkyl ethers, based on the following (a) solubility, and (b) presence or absence of swelling properties,
A first organic solvent: having both the solubility of (a) and the swellability of (b);
Second organic solvent: (a) not soluble but (b) swellable,
Third organic solvent: (a) has neither solubility nor (b) swelling,
It is proposed that the first and second organic solvents are used in combination, or the first to third organic solvents are used in combination to obtain the above-mentioned effects. ing.
(a) By adding 0.2 g of vinyl chloride-vinyl acetate copolymer [number average molecular weight Mn = 22,000, vinyl acetate content 14% by mass] to 20 ml of an organic solvent, the mixture is stirred at 25 ° C. for 1 hour. , Solubility that can dissolve the whole amount.

The detailed procedure for the solubility test is as follows.
20 ml of the organic solvent to be evaluated is put into a beaker, a stirrer whose surface is coated with Teflon (registered trademark) is added, and the mixture is allowed to stand in a thermostatic bath set at 25 ± 1 ° C. to stabilize the liquid temperature.
Next, the magnetic stirrer is operated, the stirrer is rotated, and the stirring is performed under conditions of a rotation speed of 500 rpm or more and 1,000 rpm or less.

While stirring, 0.2 g of powdered vinyl chloride-vinyl acetate copolymer was added and stirring was continued for 1 hour, and then the solution was visually observed.
Then, as described above, a transparent solution is evaluated as soluble, and a solution in which the solution is cloudy or a solid is precipitated is evaluated as not soluble.
(b) A water-based hard polyvinyl chloride pipe (VP) defined in Japanese Industrial Standards JIS K6742: 2004, having a standard outer diameter of 32.0 mm and a nominal inner diameter of 25 mm, is immersed in an organic solvent, Swellability that can be swollen so that the change rate of the inner diameter becomes 1% or more when allowed to stand at 60 ° C. for 3 days.

The detailed procedure of the swelling test is as follows.
300 ml of the organic solvent to be evaluated is placed in a beaker and allowed to stand in a thermostat set to 60 ± 1 ° C. to stabilize the liquid temperature.
Next, after immersing a hard vinyl chloride pipe (VP) for water supply which has been cut into a length of 80 mm in advance and measured the inner diameter in the liquid and left to stand for 3 days, the inner diameter is immediately measured by pulling up from the liquid.

  And the thing with a change rate of 1% or more of the internal diameter before and behind immersion is evaluated as swellable, and less than 1% is evaluated as not swellable.

JP 2009-74034 A JP 2007-169492 A

When continuously printing on the surface of a long polyvinyl chloride sheet such as a banner or banner using the non-aqueous inkjet ink, the printed polyvinyl chloride sheet or the like is wound into a roll. In general, the printed surfaces are stacked in a so-called zigzag manner so that the printed surfaces are in contact with each other.
However, when the PVC sheets are folded in a zigzag manner like the latter, even if the printing before the stacking is apparently dry, the stacked prints will stick to each other if left standing in the stacked state. When the paper is expanded again, there is a possibility that one or both of the prints may be peeled off.

In addition, when the above-mentioned sticking occurs when a polyvinyl chloride sheet or the like has a laminated structure of two or more layers, the polyvinyl chloride sheet does not peel off when trying to spread after standing in a zigzag folded state. And the like may be separated from each other.
Among these two or three types of organic solvents, the cause of this is that they quickly penetrate into the inside of the printing, and further into the interior of the polyvinyl chloride sheet, etc. The second organic solvent responsible for so-called osmotic drying, which is in a dry state, is insufficient in terms of volatilization and drying, which volatilizes itself and makes the printing essentially dry. It can be considered that it tends to remain inside a sheet or the like.

In other words, the second organic solvent remaining inside the apparently dried polyvinyl chloride sheet or the like is caused by a load applied when the polyvinyl chloride sheet or the like is stacked. As a result of oozing out on the surface of the printing and swelling or partially dissolving the binder resin constituting the printing on the other side, the printings are stuck together.
Therefore, in order to suppress such sticking, in Patent Document 1, it is considered to use an acrylic resin having a weight average molecular weight Mw of 8,000 to 40,000 together with the polyvinyl chloride resin as a binder resin. Has been.

The acrylic resin is concentrated on the surface of the printing in the drying process of printing based on the difference in compatibility and affinity with the polyvinyl chloride resin, and the acrylic resin has a high concentration on the surface. It is considered that the region functions to suppress swelling, partial dissolution, and the like due to oozing out of the second organic solvent remaining in the inside of printing, a polyvinyl chloride sheet, or the like.
However, according to a study by the inventor, when the conventional acrylic resin having the weight average molecular weight Mw is used, the condition is more severe than the condition described in Patent Document 1, for example, standing after printing. It has been clarified that the effect of preventing sticking is not yet sufficient when the time is shortened and the sheets are folded in a shorter time.

The ability to shorten the standing time is extremely important in improving the productivity of hanging curtains and banners using polyvinyl chloride sheets.
Further, it has not yet been put into practical use to print a fluorescent color such as a fluorescent marker using the non-aqueous inkjet ink.
Examples of fluorescent colorants for fluorescent color printing include inorganic or organic fluorescent pigments and fluorescent dyes.

However, among these inorganic fluorescent pigments, since the particle size is as large as about 10 to 100 μm, they cannot be ejected from the nozzles of an ink jet printer and cannot be used as a colorant for non-aqueous ink jet inks.
On the other hand, the organic fluorescent pigment is constituted by, for example, dyeing fine particles of a resin with a fluorescent dye, or coating the core of the fluorescent dye with a resin shell, and the like, and as a colorant for an aqueous inkjet ink. Can be preferably used.

  However, when the organic fluorescent pigment is blended with a non-aqueous inkjet ink containing the organic solvent, a part of the resin constituting the fluorescent pigment dissolves or swells, and the fluorescent pigment aggregates in the non-aqueous inkjet ink. It becomes easy to do. For this reason, there is a problem that the storage stability of the non-aqueous ink jet ink is lowered, or the ink cannot be stably ejected from the nozzle of the ink jet printer.

  Since fluorescent dyes are compatible with non-aqueous inkjet inks at the molecular level, problems such as storage stability and ejection stability do not occur. However, when printing on the surface of a polyvinyl chloride sheet, etc. It does not stay on the surface, but migrates (migrate) to the inside of the polyvinyl chloride sheet or the like with the penetration of the organic solvent, so that it is impossible to print a good fluorescent color having a sufficient density on the surface. There's a problem.

  The present invention has excellent storage stability, excellent printing fixability, and can print images and characters with excellent image quality, such as water resistance, light resistance, and friction resistance, on the surface of a polyvinyl chloride sheet or the like. Another object of the present invention is to provide a non-aqueous inkjet ink that is particularly excellent in the effect of preventing sticking between prints when printed on the surface of a long polyvinyl chloride sheet or the like and stacked in a zigzag manner.

Another object of the present invention is a non-aqueous inkjet which is excellent in storage stability, ejection stability, and the effect of preventing sticking, and can print a good fluorescent color having a sufficient concentration on the surface of a polyvinyl chloride sheet or the like. To provide ink.
Another object of the present invention is to provide an ink set containing the non-aqueous inkjet ink.

The present invention is a non-aqueous inkjet ink containing a colorant, a binder resin, and an organic solvent, and the binder resin is preliminarily blended in a polymer state and has a glass transition temperature Tg of 60 ° C. or higher and 95 ° C. The acrylic resin having a weight average molecular weight Mw of 50,000 or more and 140,000 or less and a polyvinyl chloride resin are used in combination, and the blending ratio of the acrylic resin is the polyvinyl chloride resin, and The total amount of the acrylic resin is 10% by mass or more and 35% by mass or less, and as the organic solvent , only polyalkylene glycol alkyl ethers are used, or the polyalkylene glycol alkyl ethers and the formula (1) :

[In the formula, R ¹ , R ² And R ³ Denote the same or different alkyl groups. ]
Is used together so that the blending ratio of the polyalkylene glycol alkyl ethers is 70% by mass or more of the total amount of the organic solvent.

According to the present invention, by selectively using an organic solvent in which polyalkylene glycol alkyl ethers are blended in the above proportion, as described above, a conventional mixed solvent containing the aprotic polar organic solvent can be obtained. The storage stability of the non-aqueous inkjet ink can be improved compared to the case of using it.
In addition, the combined use of the organic solvent and a polyvinyl chloride resin as a binder resin improves printing fixability, and is excellent in water resistance, light resistance, friction resistance, etc. on the surface of a polyvinyl chloride sheet and the like. Images and characters with good image quality can be printed.

In addition to the polyvinyl chloride resin, a binder resin having a weight average molecular weight Mw larger than that of the conventional resin as described above and an acrylic resin having a predetermined glass transition temperature Tg is previously blended in a polymer state. This makes it possible to prevent sticking between prints when the polyvinyl chloride sheets and the like are stacked in a folded manner even under conditions that are more severe than conventional ones.
This is because the acrylic resin used in the polymer state in advance having the weight average molecular weight Mw and the glass transition temperature Tg is chemically stable and physically high in strength. This is because the function of suppressing swelling and partial dissolution due to the leaching of the second organic solvent remaining inside the printing or polyvinyl chloride sheet due to the region formed in the vicinity of the surface of the sheet can be further strengthened. It is done.

The blending ratio of the acrylic resin needs to be 10% by mass or more and 35% by mass or less of the total amount of the polyvinyl chloride resin and the acrylic resin.
By making the blending ratio of the acrylic resin within the above range, the above-mentioned effect by using the acrylic resin in combination with the polyvinyl chloride resin can be expressed better, and a polyvinyl chloride sheet after printing, etc. It is possible to further improve the effect of preventing sticking between prints when they are stacked in a zigzag shape.

As the organic solvent, only the polyalkylene glycol alkyl ethers are used alone as described above, or the ratio of the polyalkylene glycol alkyl ethers and the amide solvent represented by the formula (1) is as described above. in you combination.
In the former case, the effect of preventing sticking of printing and the fixing property of printing are improved, and the surface of a polyvinyl chloride sheet or the like has excellent image quality such as water resistance, light resistance, and friction resistance. In particular, the storage stability of the non-aqueous inkjet ink can be improved while maintaining the effect of printing good images and characters at a practical level.

  In the latter case, the amide solvent represented by the above formula (1) is excellent in volatile drying property that quickly volatilizes and substantially dries the printing, so that the sticking of the printing is further prevented. can do. Moreover, although the amide solvent is a kind of aprotic polar organic solvent, it has excellent compatibility and affinity with polyalkylene glycol alkyl ethers compared to conventional aprotic polar organic solvents, so that it is stable in storage. There is no risk of losing sex.

Therefore, in the latter case, the effect of printing images and characters with good image quality with excellent water resistance, light resistance, friction resistance, etc. on the surface of a polyvinyl chloride sheet, etc., by improving the fixing property of printing, While maintaining the storage stability of the non-aqueous inkjet ink at a practical level, it is possible to improve the effect of particularly preventing printing sticking.
When printing a fluorescent color using the non-aqueous inkjet ink of the present invention, a fluorescent dye is used as the colorant, and the fluorescent dye is soluble in the non-aqueous inkjet ink and further in the organic solvent. A third resin having a function of preventing the dye from moving from the surface of the medium to the inside is blended.

Due to the function of the third resin, the fluorescent dye can be prevented from migrating from the surface of the polyvinyl chloride sheet or the like along with the penetration of the organic solvent.
Therefore, the organic solvent is generally less permeable to a polyvinyl chloride sheet or the like than a conventional nitrogen-containing heterocyclic compound and the like, and is difficult to penetrate into the polyvinyl chloride sheet or the like with a fluorescent dye. In combination, it becomes possible to print a good fluorescent color having a sufficient density on the surface of the polyvinyl chloride sheet or the like.

The function of the third resin can be expressed based on, for example, a difference in affinity and compatibility with a fluorescent dye with a polyvinyl chloride sheet or the like.
For example, as the third resin, a resin having a higher affinity and compatibility with a fluorescent dye than a polyvinyl chloride resin constituting at least the surface layer, such as a polyvinyl chloride sheet, is used. Then, since the third resin does not penetrate into the interior with the penetration of the organic solvent and remains on the surface of the polyvinyl chloride sheet or the like, the fluorescent dye is more than the one that penetrates into the interior of the polyvinyl chloride sheet or the like. However, together with the third resin, the amount remaining on the surface of the polyvinyl chloride sheet or the like is increased, and as a result, the surface of the polyvinyl chloride sheet or the like is printed with a good fluorescent color having a sufficient concentration. be able to.

The present invention is an ink set including a plurality of non-aqueous inkjet inks, wherein at least one non-aqueous inkjet ink of the plurality of colors is the non-aqueous inkjet ink of the present invention. It is.
According to the present invention, for example, by using a non-aqueous inkjet ink which is printed at least last on the surface of a polyvinyl chloride sheet or the like by printing using an inkjet printer, the polyvinyl chloride sheet or the like is obtained. It is possible to more surely prevent sticking between prints when stacked in a zigzag shape.

Of the ink sets, the configuration of the non-aqueous inkjet ink of the present invention is not limited to the one color, and two or more non-aqueous inkjet inks of the ink set may be configured of the present invention. And all the non-aqueous inkjet ink which comprises an ink set is good also as a structure of this invention.
Patent Document 2 discloses a non-aqueous inkjet ink containing, as a binder resin, an acrylic resin obtained by solution polymerization of an acrylic monomer in an organic solvent constituting the non-aqueous inkjet ink. The acrylic resin preferably has a glass transition temperature Tg of 80 ° C. or higher and a weight average molecular weight Mw of 10,000 to 100,000. As the binder resin, it is said that a polyvinyl chloride resin may be used in combination with the acrylic resin.

However, as described above, the acrylic resin produced by solution polymerization in an organic solvent has excellent solubility and affinity for the organic solvent as described in Patent Document 2, and is used in combination as a binder resin. It has high compatibility and affinity for polyvinyl chloride resin.
Therefore, the acrylic resin is sufficiently concentrated on the surface of the printing during the printing drying process, unlike the acrylic resin used in the present invention, which is used in the production of the non-aqueous inkjet ink in the polymer state in advance. It is not possible to form a sufficiently high concentration region in the vicinity of the surface.

  Therefore, even if the glass transition temperature Tg and the weight average molecular weight Mw overlap with the ranges defined in the present invention, the acrylic resin described in the above-mentioned Patent Document 2 cannot be used in printing or polyvinyl chloride sheets. The effect of suppressing swelling, partial dissolution, and the like due to leaching of the remaining second organic solvent cannot be obtained.

  According to the present invention, it has excellent storage stability, excellent printing fixability, and has excellent image quality and images with excellent water resistance, light resistance, friction resistance, etc. on the surface of a polyvinyl chloride sheet or the like. In addition to printing, it is possible to provide a non-aqueous inkjet ink that is particularly excellent in the effect of preventing sticking between prints when printed on the surface of a long polyvinyl chloride sheet or the like and stacked in a zigzag manner.

In addition, according to the present invention, the non-aqueous inkjet is excellent in storage stability, ejection stability, and the effect of preventing sticking, and can print a good fluorescent color having a sufficient concentration on the surface of a polyvinyl chloride sheet or the like. Ink can be provided.
Furthermore, according to this invention, the ink set containing the said non-aqueous inkjet ink can be provided.

《Non-aqueous inkjet ink》
The non-aqueous inkjet ink of the present invention includes a colorant, a binder resin, and an organic solvent, and the binder resin is preliminarily blended in a polymer state and has a glass transition temperature Tg of 60 ° C. or higher and 95 ° C. or lower. In addition, an acrylic resin having a weight average molecular weight Mw of 50,000 or more and 140,000 or less, and a polyvinyl chloride resin are used in combination, and the blending ratio of the acrylic resin is the polyvinyl chloride resin and the acrylic resin. The total amount of the resin is 10% by mass or more and 35% by mass or less, and as the organic solvent , only the polyalkylene glycol alkyl ethers are used, or the polyalkylene glycol alkyl ethers and the formula (1) and amide-based solvent represented, the mixing ratio of the polyalkylene glycol alkyl ethers Is characterized in that in combination so that more than 70 wt% of the total amount of organic solvent.

<Acrylic resin>
In the present invention, the glass transition temperature Tg of the acrylic resin is limited to the above range for the following reason.
In other words, when the glass transition temperature Tg of the acrylic resin is less than 60 ° C., the effect of preventing the sticking between the prints when printing on the surface of the long polyvinyl chloride sheet or the like and overlapping in a zigzag manner is obtained. I can't.

  On the other hand, when the glass transition temperature Tg of the acrylic resin exceeds 95 ° C., the printing made of the non-aqueous inkjet ink is too hard and brittle, and cannot sufficiently follow the soft polyvinyl chloride sheet or the like. There is a problem that when the polyvinyl chloride sheet or the like is folded, bent, or subsequently expanded or stretched, it is easily peeled off from the surface of the polyvinyl chloride sheet or the like.

Further, the reason why the weight average molecular weight Mw of the acrylic resin is limited to the above range is as follows.
That is, when the weight average molecular weight Mw of the acrylic resin is less than 50,000 , the effect of preventing the sticking between prints when printing on the surface of a long polyvinyl chloride sheet or the like and overlapping in a zigzag manner is provided. I can't get it.

On the other hand, when the weight average molecular weight Mw of the acrylic resin exceeds 140,000, the storage stability of the non-aqueous inkjet ink is lowered, and the binder resin and the colorant are likely to aggregate or settle. Arise.
On the other hand, by using an acrylic resin in which the glass transition temperature Tg and the weight average molecular weight Mw are both within the above ranges, the problems such as peeling and storage stability do not occur, and compared with the conventional case. Even under severe conditions, it is possible to prevent sticking between prints when a polyvinyl chloride sheet or the like is stacked in a folded shape.

The present invention has a glass transition temperature Tg of such contact acrylic resin in a usual manner, and be represented with a value measured by differential scanning calorimetry.
In addition, the weight average molecular weight Mw of the acrylic resin, or the weight average molecular weight Mw and the number average molecular weight Mn of the polyvinyl chloride resin described later are both TSKgelsuper HZM-N columns (manufactured by Tosoh Corporation). The weight determined in terms of polystyrene from the results of measurement using a gel permeation chromatograph [HLC-8220GPC manufactured by Tosoh Corporation] under conditions of flow rate: 0.35 ml / min and developing solvent: THF. It will be expressed in terms of average molecular weight.

As the acrylic resin, any of various acrylic resins satisfying the ranges of the glass transition temperature Tg and the weight average molecular weight Mw can be used.
That is, a homopolymer composed of any one of acrylic monomers such as acrylic acid, methacrylic acid, salts thereof, esters with alkyl, polyester, polyether, etc., a copolymer composed of two or more, or one or Examples of the acrylic resin include one or two or more of a copolymer of two or more kinds of acrylic monomers and other monomers having a glass transition temperature Tg and a weight average molecular weight Mw within the above ranges.

The acrylic resin is used in the manufacture of a non-aqueous inkjet ink in a polymer state in advance. This is because an acrylic resin obtained by solution polymerization of a monomer in an organic solvent constituting a non-aqueous ink-jet ink cannot obtain the effects of the present invention as described above.
Specific examples of the acrylic resin include, but are not limited to, for example, A-11 [glass transition temperature Tg: 100 ° C., weight average molecular weight Mw: PARALOID (Paraloid, registered trademark) series manufactured by Rohm and Haas. 125,000, basic composition: MMA], A-14 [glass transition temperature Tg: 100 ° C., weight average molecular weight Mw: 70,000, basic composition: MMA], B-44 [glass transition temperature Tg: 60 ° C., weight Average molecular weight Mw: 140,000, basic composition: MMA / EA], B-60 [glass transition temperature Tg: 75 ° C., weight average molecular weight Mw: 50,000, basic composition: MMA / BMA], B-64 [glass] Transition temperature Tg: 60 ° C., weight average molecular weight Mw: 140,000, basic composition: MMA / EA] and the like.

<Polyvinyl chloride resin>
Examples of the polyvinyl chloride resin include one or more of a vinyl chloride homopolymer and a copolymer of vinyl chloride and another monomer.
Above all, as a polyvinyl chloride resin, since a large amount of organic solvent is not used unlike the solution polymerization method, facilities such as exhaust treatment and waste liquid treatment are not required without volatilizing the organic solvent into the atmosphere. Polyvinyl chloride resins synthesized by suspension polymerization or emulsion polymerization are preferred.

In particular, when vinyl acetate is copolymerized with vinyl chloride, as described above, the solubility in organic solvents is improved, and the flexibility of images and characters printed on the surface of polyvinyl chloride sheets and the like is increased. It can be increased to improve the scratch resistance of printing. Therefore, a vinyl chloride-vinyl acetate copolymer is preferably used as the polyvinyl chloride resin.
The molecular weight and vinyl acetate content of the vinyl chloride-vinyl acetate copolymer can be arbitrarily set, but the vinyl chloride-vinyl acetate copolymer synthesized by the suspension polymerization method has a number average molecular weight Mn of 5,000 or more, In particular, it is preferably 10,000 or more, more preferably 100,000 or less, and particularly preferably 30,000 or less.

When the number average molecular weight Mn is less than the above range, the fixing property of the vinyl chloride-vinyl acetate copolymer to the polyvinyl chloride sheet or the like decreases, and the surface of the polyvinyl chloride sheet or the like has water resistance, light resistance, and friction resistance. There is a possibility that the effect of printing images and characters with excellent image quality and excellent image quality cannot be obtained sufficiently.
On the other hand, when the above range is exceeded, the viscosity of the non-aqueous inkjet ink becomes too high, and there is a possibility that it cannot be discharged well as droplets from the nozzles of the head of the inkjet printer.

The vinyl chloride-vinyl acetate copolymer synthesized by the suspension polymerization method has a vinyl acetate content of 1% by mass or more, preferably 10% by mass or more, particularly preferably 13% by mass or more, particularly 36% by mass or less. It is preferably 22% by mass or less, particularly preferably 15% by mass or less.
If the vinyl acetate content is less than the above range, the solubility of the vinyl chloride-vinyl acetate copolymer is lowered, and the vinyl chloride-vinyl acetate copolymer is likely to be precipitated in the non-aqueous inkjet ink. Ink storage stability may be reduced.

If the above range is exceeded, the fixing property of the vinyl chloride-vinyl acetate copolymer to the polyvinyl chloride sheet or the like decreases, and the surface of the polyvinyl chloride sheet or the like has water resistance, light resistance, and friction resistance. There is a possibility that the effect of printing images and characters with excellent image quality and the like cannot be sufficiently obtained.
As the vinyl chloride-vinyl acetate copolymer synthesized by the suspension polymerization method, for example, among SOLBIN (Solvine, registered trademark) series vinyl chloride-vinyl acetate copolymers manufactured by Nissin Chemical Industry Co., Ltd. CL (number average molecular weight Mn: 25,000, vinyl acetate content: 14% by mass, glass transition temperature Tg: 70 ° C.), CNL (number average molecular weight Mn: 12,000, vinyl acetate content: 10% by mass, glass transition temperature) Tg: 76 ° C.), C5R (number average molecular weight Mn: 27,000, vinyl acetate content: 21% by mass, glass transition temperature Tg: 68 ° C.), AL (number average molecular weight Mn: 22,000, vinyl acetate content: 2) % By mass, glass transition temperature Tg: 76 ° C., TA5R (number average molecular weight Mn: 28,000, vinyl acetate content: 1% by mass, glass transition temperature Tg: 78 ° C.) TAO (number average molecular weight Mn: 15,000, vinyl acetate content: 2 mass%, glass transition temperature Tg: 77 ° C.), TA3 (number average molecular weight Mn: 24,000, vinyl acetate content: 4 mass%, glass transition temperature) 1 type or 2 types or more, such as Tg: 65 degreeC).

The vinyl chloride-vinyl acetate copolymer synthesized by the emulsion polymerization method has a weight average molecular weight Mw of 5,000 or more, preferably 30,000 or more, particularly 45,000 or more, preferably 100,000 or less, Among these, 60,000 or less, particularly 55,000 or less are preferable.
When the weight average molecular weight Mw is less than the above range, the fixing property of the vinyl chloride-vinyl acetate copolymer to the polyvinyl chloride sheet or the like decreases, and the surface of the polyvinyl chloride sheet or the like has water resistance, light resistance, and friction resistance. There is a possibility that the effect of printing images and characters with excellent image quality and excellent image quality cannot be obtained sufficiently.

On the other hand, when the above range is exceeded, the viscosity of the non-aqueous inkjet ink becomes too high, and there is a possibility that it cannot be discharged well as a droplet from the nozzle of the head of the inkjet printer.
The vinyl chloride-vinyl acetate copolymer synthesized by the emulsion polymerization method has a vinyl acetate content of 1% by mass or more, preferably 10% by mass or more, particularly preferably 14% by mass or more, and 36% by mass or less, especially 20%. It is preferably at most 16 mass%, particularly at most 16 mass%.

If the vinyl acetate content is less than the above range, the solubility of the vinyl chloride-vinyl acetate copolymer is lowered, and the vinyl chloride-vinyl acetate copolymer is likely to be precipitated in the non-aqueous inkjet ink. Ink storage stability may be reduced.
If the above range is exceeded, the fixing property of the vinyl chloride-vinyl acetate copolymer to the polyvinyl chloride sheet or the like decreases, and the surface of the polyvinyl chloride sheet or the like has water resistance, light resistance, and friction resistance. There is a possibility that the effect of printing images and characters with excellent image quality and the like cannot be sufficiently obtained.

  The vinyl chloride-vinyl acetate copolymer synthesized by the emulsion polymerization method is, for example, the product number E15 / 45 (weight) of the vinyl chloride-vinyl acetate copolymer of VINNOL (Vinol, registered trademark) series manufactured by Wacker Chemie. Average molecular weight Mw: 45,000-55,000, vinyl acetate content: 15.0 ± 1.0 mass%, glass transition temperature Tg: 75 ° C., H14 / 36 (weight average molecular weight Mw: 30,000-40, 000, vinyl acetate content: 14.4 ± 1.0 mass%, glass transition temperature Tg: 69 ° C., H15 / 42 (weight average molecular weight Mw: 35,000 to 50,000, vinyl acetate content: 14.0 ± 1.0% by mass, glass transition temperature Tg: 70 ° C., H40 / 43 (weight average molecular weight Mw: 40,000 to 50,000, vinyl acetate content: 34.3 ± 0.0% by mass, glass transition temperature Tg: 58 ° C., E15 / 45M (weight average molecular weight Mw: 50,000-60,000, vinyl acetate content: 15.0 ± 1.0% by mass, glass transition temperature Tg: 76 ° C.) or the like.

<Binder resin blending ratio>
The mixing ratio of the acrylic resins is 10% by weight of the total amount of the polyvinyl chloride resin and an acrylic resin or is limited to 35 mass% or less.
When the blending ratio of the acrylic resin is less than the above range, when the acrylic resin is blended, the polyvinyl chloride sheet or the like is folded in a zigzag manner even under the severer conditions as compared with the conventional case. , the effect of preventing the sticking of printing each other not be obtained sufficiently.

In addition, when the above range is exceeded, the blending ratio of the polyvinyl chloride resin is relatively reduced, the fixing property by blending the polyvinyl chloride resin is insufficient, and the surface of the polyvinyl chloride sheet or the like is insufficient. , water resistance, lightfastness, the effect of printing a good image and characters having excellent image quality rub resistance and the like not be obtained sufficiently.
The total blending ratio of the acrylic resin and the polyvinyl chloride resin is preferably 1% by mass or more, particularly preferably 3% by mass or more, more preferably 10% by mass or less, particularly 7% by mass, based on the total amount of the non-aqueous inkjet ink. % Or less is preferable.

If the blending ratio is less than the above range, the fixability by blending the binder resin is insufficient, and the surface of the polyvinyl chloride sheet or the like has a good image quality with excellent water resistance, light resistance, friction resistance, etc. There is a possibility that the effect of printing characters cannot be obtained sufficiently.
On the other hand, when the above range is exceeded, the viscosity of the non-aqueous inkjet ink becomes too high, and there is a possibility that it cannot be discharged well as a droplet from the nozzle of the head of the inkjet printer.

<Organic solvent>
As the organic solvent, or using a polyalkylene glycol alkyl ethers alone, or with the polyalkylene glycol alkyl ether, and amide-based solvent represented by the formula (1), the formulation of the polyalkylene glycol alkyl ethers It uses together so that a ratio may be 70 mass% or more of the total amount of an organic solvent .
In the latter combination system, if the blending ratio of the polyalkylene glycol alkyl ether is less than the above range, the storage stability of the non-aqueous inkjet ink is low, and there is a problem that the binder resin and the colorant are likely to aggregate or settle. .

On the other hand, the storage stability of the non-aqueous inkjet ink can be improved by selectively using the organic solvent in which the polyalkylene glycol alkyl ether is blended in the above ratio, compared with the case where the conventional mixed solvent described above is used. Can be improved.
In addition, the upper limit of the mixture ratio of polyalkylene glycol alkyl ethers is 90 mass%. If the blending ratio of the amide solvent represented by the formula (1) is smaller than this range, the combined effect may not be sufficiently obtained.

  Among the above, when only the polyalkylene glycol alkyl ethers are used alone, the effect of preventing sticking of printing and the fixability of printing are improved, and the surface of the polyvinyl chloride sheet or the like is water resistant. In particular, the storage stability of the non-aqueous inkjet ink can be improved while maintaining the effect of printing images and characters having excellent image quality, such as excellent light resistance and friction resistance, at a practical level.

In the case of the latter combination, as the other organic solvent that can be used in combination with the polyalkylene glycol alkyl ether, the above-described conventional aprotic polar organic solvent can be considered.

However, in consideration of maintaining the storage stability of the non-aqueous inkjet ink at a practical level, in the present invention, the other organic solvent is represented by the formula (1):

[Wherein R ¹ , R ² , and R ³ represent the same or different alkyl groups. ]
It is limited to the amide solvent represented by these.
The amide solvent represented by the above formula (1) has excellent osmotic drying properties for polyvinyl chloride sheets and the like, and also has excellent volatile drying properties that quickly evaporate and substantially dry the printing. Sticking can be prevented even better. Moreover, although the amide solvent is a kind of aprotic polar organic solvent, it has excellent compatibility and affinity with polyalkylene glycol alkyl ethers compared to conventional aprotic polar organic solvents, so that it is stable in storage. There is no risk of losing sex.

Therefore, by using the amide solvent represented by the formula (1) together with polyalkylene glycol alkyl ethers, the fixing property of printing is improved, and the surface of the polyvinyl chloride sheet or the like has water resistance, light resistance, Improving the effect of printing images and characters with excellent image quality with excellent friction resistance, etc., and preventing the sticking of printing, while maintaining the storage stability of non-aqueous inkjet ink at a practical level be able to.

The blending ratio of the entire organic solvent is the remaining amount of other components. That is, the total blending ratio of the organic solvent may be set so that the total amount of the organic solvent added to the colorant, binder resin, or the like is 100% by mass.
(Polyalkylene glycol alkyl ethers)
As described above, the polyalkylene glycol alkyl ethers can be classified into the first to third types, among which the first and second organic solvents are used in combination, or It is preferable to use the first to third organic solvents in combination.

Among these, examples of the first organic solvent include one or more of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and diethylene glycol ethyl methyl ether. Of these, diethylene glycol ethyl methyl ether is particularly preferable.
Examples of the second organic solvent include one or more of diethylene glycol diethyl ether, diethylene glycol isopropyl methyl ether, diethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, and propylene glycol dimethyl ether. Among these, one or more of diethylene glycol diethyl ether, tetraethylene glycol dimethyl ether, and propylene glycol dimethyl ether are particularly preferable.

  Further, as the third organic solvent, for example, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monoethyl ether Butyl ether, triethylene glycol butyl methyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, isopropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol Lumpur dimethyl ether, tripropylene glycol monomethyl ether, and one or more of tripropylene glycol dimethyl ether.

  In particular, one or more of ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, and tripropylene glycol dimethyl ether are preferable.

In the mixed system in which the first and second organic solvents are used in combination, the blending ratio of the first organic solvent is preferably 5% by mass or more, particularly 8% by mass or more of the total amount of the mixed system. 50% by mass or less, and particularly preferably 40% by mass or less.
On the other hand, in the mixed system using the first to third organic solvents in combination, the blending ratio of the first organic solvent is 5% by mass or more, particularly 8% by mass or more of the total amount of the mixed system. Is preferably 50% by mass or less, and particularly preferably 40% by mass or less. Further, the blending ratio of the third organic solvent is preferably 1% by mass or more, particularly preferably 2% by mass or more, more preferably 50% by mass or less, and particularly preferably 40% by mass or less, based on the total amount of the mixed system.

When the colorant is a fluorescent dye, it is particularly preferable to use the first to third organic solvents in combination.
In the three types of combined systems, the first organic solvent is not as much as an aprotic polar organic solvent such as a nitrogen-containing heterocyclic compound, but a polyvinyl chloride sheet or the like, and a polyvinyl chloride resin as a binder resin. While having solubility, the third organic solvent does not have solubility in the polyvinyl chloride sheet or the like and the polyvinyl chloride resin. In addition, the three organic solvents including the second organic solvent are very compatible.

Therefore, when the three organic solvents are used in combination, the third organic solvent suppresses the first organic solvent from moving into the polyvinyl chloride sheet or the like with the fluorescent dye, It works to stay on the surface of vinyl sheets.
Further, since the third organic solvent has a high surface tension with respect to the surface of the polyvinyl chloride sheet or the like due to the action of the hydroxyl group contained in the molecule, the contact angle of the non-aqueous inkjet ink droplets reaching the surface with respect to the surface It works to enlarge. Therefore, the spread of the ink on the surface in the surface direction can also be suppressed.

  In addition, the second organic solvent is excellent in compatibility with the first and third organic solvents, and has good moisture properties with respect to a polyvinyl chloride sheet or the like and a polyvinyl chloride resin as a binder resin. Therefore, the second organic solvent contributes to the improvement of the solubility of the polyvinyl chloride resin as the binder resin by the first organic solvent and the stability of the non-aqueous inkjet ink, and the non-aqueous inkjet ink. It also contributes to improving the fixability to the surface of a polyvinyl chloride sheet or the like.

Therefore, by using the three kinds of organic solvents in combination, it is possible to print a favorable fluorescent color having a higher concentration on the surface of a polyvinyl chloride sheet or the like.
In the case of printing fluorescent colors, in the three types of combined systems, the blending ratio of the third organic solvent is preferably 1% by mass or more, particularly 2% by mass or more, based on the total amount of the combined system, and 7% by mass. % Or less, and particularly preferably 6% by mass or less.

When the blending ratio is less than the above range, the above effect cannot be obtained sufficiently, and there is a possibility that good fluorescent color printing having a high concentration cannot be performed on the surface of a polyvinyl chloride sheet or the like.
On the other hand, when the blending ratio is larger than the above range, the fixability of the non-aqueous inkjet ink on the surface of the polyvinyl chloride sheet or the like is lowered, or due to insufficient solubility of the polyvinyl chloride resin as the binder resin. Ink stability may be reduced.

The blending ratio of the first organic solvent is 10% by mass or more, more preferably 15% by mass or more, particularly preferably 20% by mass or more of the total amount of the combined system, 35% by mass or less, especially 30% by mass or less, In particular, it is preferably 27% by mass or less.
When the blending ratio is less than the above range, the fixability of the non-aqueous inkjet ink on the surface of the polyvinyl chloride sheet or the like is reduced, or the solubility of the polyvinyl chloride resin as the binder resin is insufficient. Stability may be reduced.

On the other hand, when the blending ratio is larger than the above range, the above effect cannot be sufficiently obtained, and there is a possibility that good fluorescent color having a high concentration cannot be printed on the surface of a polyvinyl chloride sheet or the like. .
The blending ratio of the second organic solvent is the remaining amount of the blending ratio of the first and third organic solvents. That is, what is necessary is just to set a compounding ratio so that the 2nd organic solvent may be added and the total amount of three types of organic solvents may be 100 mass%.

(Amido solvent of formula (1))
In the amide solvent represented by the formula (1), the alkyl groups corresponding to R ^{1 to} R ³ in the formula are each independently methyl, ethyl, n-propyl, isopropyl, n- Examples thereof include alkyl groups having 1 to 8 carbon atoms such as butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, heptyl group and octyl group.

Among ^them, it is preferred total number of carbon atoms of R 1 to R ³ is within the range of 3-6, especially in ^R 1, ^{R 2} are both methyl groups in the formula (1), and ^{R 3} is a carbon number 1 Combinations of ~ 4 alkyl groups are preferred.
Specific examples of the amide solvent (1) include, for example, the formula (2):

An amide solvent represented by the formula [molecular weight: 131.2, boiling point: 216 ° C.], and formula (3):

And at least one selected from the group consisting of amide solvents represented by the formula (molecular weight: 173.3, boiling point: 252 ° C.), and amide solvents represented by the formula (2) are particularly preferred.
The amide solvent of the formula (1) corresponds to the first organic solvent when classified by the solubility of (a) and the swelling property of (b). Therefore, when the polyalkylene glycol alkyl ether and the amide solvent of the formula (1) are used in combination, at least a part of the first organic solvent in the polyalkylene glycol alkyl ether is used as the polyalkylene glycol alkyl ether. Substitution with an amide solvent of the formula (1) is preferable within a range where the compounding ratio is 70% by mass or more.

However, at least a part of the second or third organic solvent may be substituted with an amide solvent of the formula (1), or a part of each of at least two of the first to third organic solvents. May be substituted with an amide solvent of the formula (1).
<Colorant (Part 1)>
As the colorant, a pigment excellent in light resistance and the like is preferable. Examples of the pigment include arbitrary inorganic pigments and / or organic pigments.

Among these, as inorganic pigments, various carbon blacks such as metal compounds such as titanium oxide and iron oxide, or neutral, acidic, basic, etc. produced by known methods such as contact method, furnace method, thermal method, etc. Is mentioned.
Examples of organic pigments include azo pigments, polycyclic pigments, dye chelates, nitro pigments, nitroso pigments, and aniline black.

Examples of azo pigments include azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments.
Examples of the polycyclic pigment include phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments.

Furthermore, examples of the dye chelate include a basic dye chelate and an acid dye chelate.
Depending on the color of the non-aqueous inkjet ink, one or more pigments can be blended in an arbitrary ratio. The surface of the pigment may be treated in order to improve the dispersion stability in the non-aqueous inkjet ink.

Specific examples of the pigment include the following various pigments.
(Cyan pigment)
C. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 3, 15: 4, 15: 6, 15:34, 16, 22, 60
(Magenta pigment)
C. I. Pigment Red 5, 7, 9, 12, 48 (Ca), 48 (Mn), 49, 52, 53, 57 (Ca), 57: 1, 97, 112, 122, 123, 149, 168, 177, 178 179, 184, 202, 206, 207, 209, 242, 254, 255
(Yellow pigment)
C. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 14C, 16, 17, 20, 24, 73, 74, 75, 83, 86, 93, 94, 95, 97, 98, 109, 110, 114, 117, 120, 125, 128, 129, 130, 137, 138, 139, 147, 148, 150, 151, 154, 155, 166, 168, 180, 185, 213, 214
(Black pigment)
C. I. Pigment Black 7
(Orange pigment)
C. I. Pigment Orange 36, 43, 51, 55, 59, 61, 71, 74
(Green pigment)
C. I. Pigment Green 7, 36
(Violet pigment)
C. I. Pigment Violet 19, 23, 29, 30, 37, 40, 50
The blending ratio of the pigment is preferably 0.1% by mass or more, particularly 0.4% by mass or more, and preferably 10% by mass or less, particularly preferably 8% by mass or less, based on the total amount of the non-aqueous inkjet ink.

The pigment is preferably used as a raw material for producing the non-aqueous inkjet ink in the state of a pigment dispersion prepared by dispersing in a desired solvent.
As the solvent constituting the pigment dispersion liquid, various solvents that are soluble in the organic solvent constituting the non-aqueous inkjet ink and can disperse the pigment satisfactorily can be used. In particular, one or two or more of the first to third organic solvents are preferable as the solvent constituting the pigment dispersion.

The pigment dispersion may contain various additives such as a dispersant in order to disperse the pigment satisfactorily.
<Colorant (Part 2)>
When printing a fluorescent color using the non-aqueous inkjet ink of the present invention, a fluorescent dye is used as a colorant.

As the fluorescent dye, any of various fluorescent dyes that are soluble in the organic solvent can be used. Examples of the fluorescent dye include one or more of the following various dyes.
(Oil-soluble dye)
C. I. Solvent Yellow 44, 82, 116, C.I. I. Solvent Red 43, 44, 45, 49, 60, C.I. I. Solvent Blue 5, C.I. I. Solvent Green 7
(Disperse dye)
C. I. Disperse Yellow 82, 83, 121, 124, C.I. I. Disperse Orange 11, C.I. I. Disperse Red 58, 60, C.I. I. Disperse Blue 7
(Basic dye)
Rhodamine B, C.I. I. Basic Red 1: 1, C.I. I. Basic Yellow 40, 44, C.I. I. Basic violet 7, 11, C.I. I. Basic blue 45
(Fluorescent whitening agent, Fluor Bright Agent)
C. I. FBA184
(Other fluorescent dyes)
Salicylic acid, fluorescein, eosin, thioflavine, heliodon red <Third resin>
As the third resin used in combination with the fluorescent dye, any of various resins having a function of suppressing the migration of the fluorescent dye from the surface to the inside of the medium can be used.

In particular, a resin having a higher affinity and compatibility with a fluorescent dye than a polyvinyl chloride resin constituting at least the surface layer, such as a polyvinyl chloride sheet, is preferable as the third resin.
Since the third resin does not penetrate into the interior with the penetration of the organic solvent and remains on the surface of the polyvinyl chloride sheet or the like, the fluorescent dye is more than the one that penetrates into the interior of the polyvinyl chloride sheet or the like. Along with the third resin, the amount of the resin remaining on the surface of the polyvinyl chloride sheet or the like is increased, and as a result, the surface of the polyvinyl chloride sheet or the like is printed with a good fluorescent color having a sufficient concentration. Can do.

  Examples of the third resin include benzoguanamine resins such as benzoguanamine-formaldehyde resin; melamine-formamide-sulfonamide resin, melamine-formaldehyde-sulfonamide resin, melamine-toluenesulfonamide-formaldehyde resin, allylsulfonamide-melamine- Melamine resins such as formaldehyde resin; urea resins such as urea-formaldehyde resin; acrylic resins such as styrene-acrylonitrile copolymer and acrylic acid copolymer; sodium sulfonated styrene-divinylbenzene copolymer Examples thereof include one or two or more of styrene-based resin; polyamide-based resin; amino resin; formaldehyde-p-toluenesulfonamide resin. From among the above resins, if the affinity and compatibility with the fluorescent dye to be used are selected and used, as described above, those that are superior to the polyvinyl chloride resin constituting at least the surface layer such as a polyvinyl chloride sheet Good.

<Fluorescent pigment>
The fluorescent dye and the third resin may be blended separately. For example, the fluorescent dye and the third resin may be dyed with a fluorescent dye, or the core of the fluorescent dye may be covered with a resin shell. The organic fluorescent pigment thus obtained is preferably used as a starting material for the fluorescent dye and the third resin, and the fluorescent pigment is dissolved in an organic solvent.

Examples of such fluorescent pigments include NKP-4000, NKP-8300, NKP-9200, NKP-9500C, NKP-9600, NKV-S, NKW-2000, NKW-2100, and NKW- manufactured by Nippon Fluorochemical Co., Ltd. 3000, NKW-3600, MPI-500C, NKS-1000 series of each color fluorescent pigment,
Sinloihi Co., Ltd. FZ-2000, FZ-2800, FZ-3040, FZ-5000, FZ-6000, FA-40, FA-200, FX-300, FA-000, SX-1000, SF-5000, SX-1000, SEL-100, FM-10, FM-100, FNP of each color of each series of series,
Fluorescent pigment of each color of each series of T, TM, GT, Z, ZQ, LFY, GPL, AGL, AGR, Phantom, manufactured by DayGlo
Fluorescent pigments of each color of Epocolor FP series manufactured by Nippon Shokubai Co., Ltd.
Fluorescent pigments of each color of Victoria Color G series made by Gokoku Color Co., Ltd.
Tosoh Co., Ltd. Cosmo Color S-1000F Series of fluorescent pigments of each color, and Stirling Color Co., Ltd. of various colors of fluorescent pigments,
1 type, or 2 or more types.

The fluorescent pigment can be blended in an arbitrary ratio of one type or two or more types according to the color of the non-aqueous inkjet ink.
The blending ratio of the fluorescent pigment is preferably 0.1% by mass or more, particularly 0.4% by mass or more, preferably 10% by mass or less, particularly preferably 8% by mass or less, based on the total amount of the non-aqueous inkjet ink.

In addition, when the fluorescent dye and the third resin are separately blended, the total blending ratio of the two may be within the above range.
<Others>
In addition to the above components, the non-aqueous inkjet ink further includes an epoxidized product for capturing chlorine generated by the dehydrochlorination reaction of the polyvinyl chloride resin, or a polymer dispersant, a surfactant, a plasticizer, a charge Inhibitors, viscosity modifiers, surface tension modifiers, leveling agents, antifoaming agents, antioxidants, radical polymerization inhibitors, pH regulators, metal coordination compounds, UV absorbers, light stabilizers, fungicides, You may mix | blend various additives, such as a biocide, in arbitrary ratios as needed.

(Epoxidized product)
Among the above, the epoxidized product suppresses the transition of the pH of the non-aqueous inkjet ink to the acidic side due to the dehydrochlorination reaction of the polyvinyl chloride resin as the binder resin, thereby causing damage to the head of the inkjet printer. It is added to make it difficult for corrosion, pigment aggregation and sedimentation to occur.

As the epoxidized product, various compounds having an epoxy group in the molecule and capable of being well dissolved in the non-aqueous inkjet ink can be used.
Examples of the epoxidized product include one or more of epoxy glyceride, epoxy fatty acid monoester, epoxy hexahydrophthalate, epoxy resin and the like. Of these, epoxy glyceride, epoxy fatty acid monoester, epoxy hexahydrophthalate and the like are preferable.

The various epoxidized products contain a large number of epoxy groups although the molecular weight is smaller than that of a polyvinyl chloride resin as a binder resin or an epoxy resin which is one of representative examples of the epoxidized product. .
For this reason, fixing of the polyvinyl chloride resin to the surface of the polyvinyl chloride sheet or the like is hindered to reduce the fixing property of printing, or the viscosity of the non-aqueous inkjet ink is increased to hinder good ejection stability. Without this, hydrochloric acid generated from the polyvinyl chloride resin can be more reliably taken into the molecule.

Among the above, as the epoxy fatty acid monoester, for example, epoxidized butyl oleate, epoxidized octyl oleate, epoxidized soybean fatty acid butyl, epoxidized soybean fatty acid octyl, epoxidized linseed oil fatty acid butyl, epoxidized linseed oil fatty acid octyl and the like 1 type or 2 types or more are mentioned.
Examples of the epoxy glycerides include oils such as soybean oil, linseed oil, cottonseed oil, safflower oil, safflower oil, sunflower oil, tung oil, castor oil, corn oil, rapeseed oil, sesame oil, olive oil, palm oil, grape seed oil, fish oil and the like. 1 type or 2 types or more of these epoxidized materials are mentioned.

Among them, epoxidized soybean oil and / or epoxidized linseed oil as an epoxy glyceride contains a larger number of epoxy groups in the molecule among the various epoxidized products, and is particularly excellent in the effects described above. It is particularly preferably used as an epoxidized product.
The blending ratio of the epoxidized product is preferably 3% by mass or more, particularly preferably 10% by mass or more, more preferably 100% by mass or less, and particularly preferably 40% by mass or less, based on the total amount of the polyvinyl chloride resin.

If the blending ratio is less than the above range, hydrochloric acid generated by the dehydrochlorination reaction of the polyvinyl chloride resin by blending the epoxidized product is taken into the molecule, and the pH of the non-aqueous inkjet ink shifts to the acidic side. There is a possibility that the suppressing effect cannot be obtained sufficiently.
When the above range is exceeded, excessive epoxidized product prevents the fixing of the polyvinyl chloride resin on the surface of the polyvinyl chloride sheet or the like, thereby lowering the fixing property of printing, or the viscosity of the non-aqueous inkjet ink. May be hindered and good ejection stability may be impaired.

  The non-aqueous inkjet ink of the present invention containing each of the above components can be used in a so-called on-demand inkjet printer such as a thermal method (thermal jet (registered trademark) method, bubble jet (registered trademark) method), piezo method, or the like. In addition, the present invention can also be used for a so-called continuous ink jet printer that performs printing by forming ink droplets while circulating ink.

<Ink set>
The present invention is an ink set including a plurality of non-aqueous inkjet inks, wherein at least one non-aqueous inkjet ink of the plurality of colors is the non-aqueous inkjet ink of the present invention. It is.
According to the present invention, for example, by using a non-aqueous inkjet ink which is printed at least last on the surface of a polyvinyl chloride sheet or the like by printing using an inkjet printer, the polyvinyl chloride sheet or the like is obtained. It is possible to more surely prevent sticking between prints when stacked in a zigzag shape.

Of the ink sets, the configuration of the non-aqueous inkjet ink of the present invention is not limited to the one color, and two or more non-aqueous inkjet inks of the ink set may be configured of the present invention. And all the non-aqueous inkjet ink which comprises an ink set is good also as a structure of this invention.
As the combination of the non-aqueous inkjet inks of the plurality of colors, for example, a combination including at least cyan (C), magenta (M), and yellow (Y) non-aqueous inkjet inks for forming a full-color image or the like. Can be mentioned. Specifically, the three colors C, M, and Y, or four colors obtained by combining the three colors with black (K), or the three colors or four colors, and light cyan (LC) and light magenta (LM). And a multicolor ink set combining light colors such as gray (GY). Of these, at least one color of non-aqueous inkjet ink may be configured as the present invention.

The following examples and comparative non-aqueous inkjet inks were prepared, measured, and tested in an environment of temperature 25 ± 1 ° C. and relative humidity 55 ± 1%, unless otherwise specified.
<Example 1>
Among the binder resins, as the acrylic resin, the above-mentioned PARALOID (registered trademark) B-60 manufactured by Rohm and Haas [glass transition temperature Tg: 75 ° C., weight average molecular weight Mw: 50,000, basic composition: MMA / BMA] was used.

As the polyvinyl chloride resin, VINNOL (registered trademark) E15 / 45M manufactured by Wacker Chemical Co., Ltd. [vinyl chloride-vinyl acetate copolymer, weight average molecular weight Mw: 50,000-60,000, acetic acid Vinyl content: 15.0 ± 1.0 mass%, glass transition temperature Tg: 76 ° C.] was used.
5 parts by mass of diethylene glycol monoethyl ether (2EG-1E) as the third organic solvent, 30.5 parts by mass of diethylene glycol diethyl ether (2EG-2E) as the second organic solvent, and tetraethylene glycol dimethyl ether (4EG-2M) ) While stirring 10 parts by mass, 1 part by mass of the acrylic resin and 3 parts by mass of the polyvinyl chloride resin were added and dispersed, and both the binder resins were swollen.

Next, 20 parts by mass of diethylene glycol ethyl methyl ether (2EG-EM) as a first organic solvent was added while stirring, and the binder resin was dissolved, and then epoxidized soybean oil [(stock ADEKA Sizer (registered trademark) O-130P manufactured by ADEKA] 0.5 parts by mass was added.
Next, a dispersion liquid in which carbon black [MA8 manufactured by Mitsubishi Chemical Corporation] as a pigment is dispersed in diethylene glycol diethyl ether (2EG-2E) as the second organic solvent at a concentration of 15.0% by mass. 30 parts by mass was prepared, and the dispersion was added to 70 parts by mass of the previous mixture under stirring. The mixture was further stirred to form a uniform phase to produce a non-aqueous inkjet ink.

  The blending ratio of each component was as follows. The blending ratio of the acrylic resin was 25% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. Furthermore, the blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.

<Example 2>
As an acrylic resin, the same amount of PARALOID B-64 (Glass transition temperature Tg: 60 ° C., weight average molecular weight Mw: 140,000, basic composition: MMA / EMA) manufactured by the same company was blended instead of B-60. A non-aqueous inkjet ink was produced in the same manner as in Example 1 except that.

The blending ratio of the acrylic resin was 25% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
<Example 3>
Other than blending the same amount of PARALOID A-14 (Glass transition temperature Tg: 95 ° C., weight average molecular weight Mw: 70,000, basic composition: MMA) manufactured by the same company instead of B-60 as an acrylic resin. Produced a non-aqueous inkjet ink in the same manner as in Example 1.

The blending ratio of the acrylic resin was 25% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
<Example 4>
A non-aqueous inkjet ink is produced in the same manner as in Example 1 except that the blending amount of B-60 as an acrylic resin is 0.4 parts by mass and the blending amount of the polyvinyl chloride resin is 3.6 parts by mass. did.

The blending ratio of the acrylic resin was 10% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
<Example 5>
A non-aqueous inkjet ink is produced in the same manner as in Example 1 except that the blending amount of B-60 as an acrylic resin is 1.4 parts by mass and the blending amount of the polyvinyl chloride resin is 2.6 parts by mass. did.

The blending ratio of the acrylic resin was 35% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
< Comparative Example 1 >
A non-aqueous inkjet ink is produced in the same manner as in Example 1 except that the blending amount of B-60 as an acrylic resin is 0.2 parts by mass and the blending amount of the polyvinyl chloride resin is 3.8 parts by mass. did.

The blending ratio of the acrylic resin was 5% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
< Comparative Example 2 >
A non-aqueous inkjet ink is produced in the same manner as in Example 1 except that the blending amount of B-60 as the acrylic resin is 1.6 parts by mass and the blending amount of the polyvinyl chloride resin is 2.4 parts by mass. did.

The blending ratio of the acrylic resin was 40% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
<Example 6 >
Instead of diethylene glycol ethyl methyl ether (2EG-EM) as the first organic solvent, an amide solvent represented by the above formula (2) [Ecamide (registered trademark) M100 manufactured by Idemitsu Kosan Co., Ltd., molecular weight: 131 .2, Boiling point: 216 ° C.] was prepared in the same manner as in Example 1 except that the same amount was blended.

The blending ratio of the acrylic resin was 25% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. Moreover, the mixture ratio of polyalkylene glycol alkyl ethers was 78 mass% of the total amount of the organic solvent.
< Comparative Example 3 >
Example except that instead of diethylene glycol ethyl methyl ether (2EG-EM) as the first organic solvent, the same amount of N-methyl-2-pyrrolidone (NMP) which is a conventional aprotic polar organic solvent was blended. In the same manner as in Example 1, a non-aqueous inkjet ink was produced.

The blending ratio of the acrylic resin was 25% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. Moreover, the mixture ratio of polyalkylene glycol alkyl ethers was 78 mass% of the total amount of the organic solvent.
< Comparative example 4 >
As an acrylic resin, instead of the B-60, NeoCryl (Neocryl, registered trademark) B-813 manufactured by DSM NeoResins +, Inc. [Glass transition temperature Tg: 64 ° C., weight average molecular weight Mw: 40,000, basic composition: EMA A non-aqueous inkjet ink was produced in the same manner as in Example 1 except that the same amount was mixed.

The blending ratio of the acrylic resin was 25% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
<Comparative Example 5 >
As an acrylic resin, the same amount of PARALOID B-66 (glass transition temperature Tg: 50 ° C., weight average molecular weight Mw: 70,000, basic composition: MMA / BMA) manufactured by the same company was blended instead of B-60. A non-aqueous inkjet ink was produced in the same manner as in Example 1 except that.

The blending ratio of the acrylic resin was 25% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
<Comparative Example 6 >
As an acrylic resin, in place of the B-60, except that the same amount of PARALOID A-21 manufactured by the same company (glass transition temperature Tg: 105 ° C., weight average molecular weight Mw: 120,000, basic composition: MMA) was blended. Produced a non-aqueous inkjet ink in the same manner as in Example 1.

The blending ratio of the acrylic resin was 25% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
<Comparative Example 7 >
An acrylic resin is not blended, the blending amount of the polyvinyl chloride resin is 4 parts by mass, and instead of diethylene glycol ethyl methyl ether (2EG-EM) as the first organic solvent, the formula (2) is used. Non-aqueous inkjet ink in the same manner as in Example 1 except that 35 parts by mass of the amide solvent to be used is blended and the amount of diethylene glycol diethyl ether (2EG-2E) as the second organic solvent is 41 parts by mass. Manufactured.

The mixing ratio of the acrylic resin was 0% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. Moreover, the mixture ratio of polyalkylene glycol alkyl ethers was 61.5 mass% of the total amount of the organic solvent.
<Comparative Example 8 >
As an acrylic resin, the same amount of PARALOID B-48N (glass transition temperature Tg: 50 ° C., weight average molecular weight Mw: 250,000, basic composition: MMA / BA) manufactured by the same company was blended instead of B-60. A non-aqueous inkjet ink was produced in the same manner as in Example 1 except that.

The blending ratio of the acrylic resin was 25% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
<Comparative Example 9 >
As an acrylic resin, instead of the B-60, NeoCryl (Neocryl, registered trademark) B-818 manufactured by DSM NeoResins + [Glass transition temperature Tg: 60 ° C., weight average molecular weight Mw: 38,000, basic composition: EA / EMA] was prepared in the same manner as in Example 1 except that the same amount was mixed.

The blending ratio of the acrylic resin was 25% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
<Comparative Example 10 >
To 300 g of diethylene glycol diethyl ether (2EG-2E) maintained at 100 ° C., a mixture of 200 g of methyl methacrylate and 1.8 g of t-butylperoxy-2-ethylhexanoate was dropped over 1.5 hours, The mixture was reacted at 100 ° C. for 2 hours and then cooled to obtain a colorless and transparent polymer solution of polymethyl methacrylate.

The glass transition temperature Tg of polymethyl methacrylate in the polymer solution was 105 ° C., and the weight average molecular weight Mw was 50,000.
Next, in the polymer solution, 3 parts by mass of the same polyvinyl chloride resin as used in Example 1 and 29 parts by mass of diethylene glycol diethyl ether (2EG-2E) per 1 part by mass of polymethyl methacrylate in the polymer solution. And 10 parts by mass of tetraethylene glycol dimethyl ether (4EG-2M) were added and stirred to swell the polyvinyl chloride resin.

Next, while continuing stirring, 20 parts by mass of diethylene glycol ethyl methyl ether (2EG-EM) was added to dissolve the polyvinyl chloride resin, and then 0.5 mass of the same epoxidized soybean oil used in Example 1 Part was added.
Then, after adding 30 parts by mass of the same carbon black dispersion prepared in Example 1 to 70 parts by mass of the mixture, the mixture was further stirred to form a uniform phase, and the non-aqueous inkjet ink was added. Manufactured.

The blending ratio of the acrylic resin was 25% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
Comparative Example 10 is a reproduction of a non-aqueous inkjet ink described in Patent Document 2 using an acrylic resin produced by solution polymerization in an organic solvent. The polymerization of the acrylic resin followed the synthesis of the polymer 2 of Patent Document 2.

<Adhesion test>
The non-aqueous inkjet ink of each of the above Examples and Comparative Examples was applied to the surface of a polyvinyl chloride tarpaulin using a wire bar (piano wire having a diameter of 0.60 mm wrapped around a metal rod), Let stand at 25 ° C for 1 hour to dry, then fold it in two, overlap the coatings and let stand for another 3 hours under a load of 1 kg from the top, then spread the tarpaulin that was folded in half The state at the time of adhesion was observed, and the presence or absence of sticking was evaluated according to the following criteria.

(Double-circle): The coating film was able to be separated neatly at the interface where it was overlapped without peeling off from the surface of the tarpaulin and without separating the tarpaulin. There is no sticking.
○: The coating film could be separated at the interface where it was superimposed without peeling off from the surface of the tarpaulin, but at that time, delamination occurred in part of the tarpaulin. There is almost no sticking.

×: coating film, surface or et al peeling of the tarpaulin Ri is was, was or cause sticking.
The one-hour drying is a severer condition than the two-hour drying in the example of Patent Document 1, and that the evaluation of ◯ or higher can be obtained under such a severe condition. This means that the effect of preventing sticking is even better.

<Peeling test>
The cellophane tape is affixed to the tarpaulin crease that has been folded in the sticking test, and then peeled off to observe the state of the paint film. The presence or absence of peeling was evaluated.
○: No peeling.

X: There is peeling.
<Storage stability test>
Before and after storing the non-aqueous inkjet inks of each of the above Examples and Comparative Examples at 50 ° C. for 2 weeks, the viscosity at each time point was measured using an R-type viscometer [RE500 manufactured by Toki Sangyo Co., Ltd. The storage stability was evaluated according to the following criteria.

A: Change rate of viscosity before and after storage was within ± 8%. Very good storage stability.
A: The rate of change in viscosity exceeded ± 8% and was within ± 10%. Good storage stability.
×: The viscosity change had super strong point of 10% ±. Storage stability is poor.
<Fixability test>
The non-aqueous inkjet ink of each of the above Examples and Comparative Examples was coated with a wire bar (doctor 0.25, piano wire with a diameter of 0.25 mm wrapped around a metal rod) on the surface of polyvinyl chloride tarpaulin. The coating film was rubbed with a 1.2 kW dryer for 1 minute in hot air, and then the coating film was rubbed with a cotton swab with a load of 50 g, and the fixability was evaluated according to the following criteria.

○: No change. Good fixability.
×: or left scratch marks on the coating, the interest had been rubbed off. Fixing failure.
The above results are shown in Tables 2 to 5.

From the result of Comparative Example 7 in Table 3 , as the binder resin, the acrylic resin is not used together with the polyvinyl chloride resin, and the blending ratio of the polyalkylene glycol alkyl ether is less than 70% by mass of the total amount of the organic solvent. In this case, since the amide solvent of the formula (2) having excellent drying properties is used as the other organic solvent, the occurrence of sticking is slight, but the storage stability of the non-aqueous inkjet ink is particularly poor. It turned out to be.

Further, from the results of Comparative Examples 5 , 6 and 8 in Tables 3 and 4 , even when an acrylic resin is used in combination, if the glass transition temperature Tg of the acrylic resin is less than 60 ° C., printing sticking occurs, and 95 ° C. It has been found that when the value exceeds 1, peeling of the printing occurs.
Further , from the results of Comparative Examples 8 , 9 , and 4 in Table 4 , even when an acrylic resin is used in combination, if the weight average molecular weight Mw of the acrylic resin is less than 50,000 , printing sticking occurs, and 140,000 is obtained. When exceeding, it turned out that the storage stability of a non-aqueous inkjet ink becomes inferior.

Further, from the results of Comparative Example 10 in Table 5 , when an acrylic resin produced by solution polymerization in an organic solvent was used, the acrylic resin had a glass transition temperature of 60 ° C. or higher and a weight average molecular weight Mw. It was found that printing sticking occurred despite the fact that it was 40,000 or more, and that the glass transition temperature of the acrylic resin exceeded 95 ° C., resulting in printing peeling.

On the other hand, from the results of Examples 1 to 6 in Tables 2 and 3, as binder resins, the glass transition temperature Tg is 60 ° C. or more and 95 ° C. or less, and the weight average molecular weight Mw is 50,000 or more, 140, 000 or less acrylic resin is used in combination with polyvinyl chloride resin, and the blending ratio of polyalkylene glycol alkyl ethers is 70% by mass or more of the total amount of organic solvent to maintain good storage stability. In addition, it was found that the sticking of the printing under the severe condition can be prevented while preventing the peeling of the printing.

However, from the results of Examples 1 , 4 , 5 and Comparative Examples 1 and 2 in Table 5, the blending of the acrylic resin in terms of the effect of preventing the sticking of printing and the effect of improving the fixing property of printing ratio, polyvinyl chloride resin, and 10 mass% or more of the total amount of the acrylic resin, it was found that there needs to be 35 mass% or less.
In particular, from the results of Examples 1 to 5, when the blending ratio of the polyalkylene glycol alkyl ethers is 100% by mass, the effect of preventing the sticking of printing and the effect of improving the fixing property of printing are practical. It was found that the storage stability of the non-aqueous inkjet ink can be improved while maintaining the level.

Further, from the results of Example 6 and Comparative Example 3 , the effect of improving the fixing property of printing and the effect of preventing the sticking of printing in particular while maintaining the storage stability of the non-aqueous inkjet ink at a practical level. to improve the other organic solvents may be used in combination with polyalkylene glycol alkyl ethers has been found that there must be an amide-based solvent represented by the formula (1).

< Example 7 >
Examples of the colorant include sodium sulfonated particles of styrene-divinylbenzene copolymer as the third resin, and C.I. I. A fluorescent pigment dyed with Disperse Yellow 82 [FNP-35, Lemon Yellow, manufactured by Singloi Co., Ltd.] was used.

Moreover, as acrylic resin among binder resins, the above-mentioned PARALOID (registered trademark) B-60 manufactured by Rohm and Haas [Glass transition temperature Tg: 75 ° C., weight average molecular weight Mw: 50,000, basic composition: MMA / BMA] was used.
As the polyvinyl chloride resin, VINNOL (registered trademark) E15 / 45M manufactured by Wacker Chemical Co., Ltd. [vinyl chloride-vinyl acetate copolymer, weight average molecular weight Mw: 50,000-60,000, acetic acid Vinyl content: 15.0 ± 1.0 mass%, glass transition temperature Tg: 76 ° C.] was used.

  5 parts by mass of diethylene glycol monoethyl ether (2EG-1E) as the third organic solvent, 30.5 parts by mass of diethylene glycol diethyl ether (2EG-2E) as the second organic solvent, and tetraethylene glycol dimethyl ether (4EG-2M) ) While stirring 10 parts by mass, 1 part by mass of the acrylic resin and 3 parts by mass of the polyvinyl chloride resin were added and dispersed, and both the binder resins were swollen.

Next, 20 parts by mass of diethylene glycol ethyl methyl ether (2EG-EM) as a first organic solvent was added while stirring, and the binder resin was dissolved, and then epoxidized soybean oil [(stock ADEKA Sizer (registered trademark) O-130P manufactured by ADEKA] 0.5 parts by mass was added.
The fluorescent pigment is added at a concentration of 15% by mass to diethylene glycol diethyl ether (2EG-2E) as the second organic solvent, and stirred at 40 ° C. for 2 hours to dissolve the fluorescent pigment, and the fluorescent dye 30 parts by mass of a solution (fluorescent pigment concentration of 15% by mass) containing the second resin and the third resin is added to the previous mixture of 70 parts by mass with stirring, and then a uniform phase is formed. The mixture was further stirred to produce a non-aqueous inkjet ink.

  The blending ratio of each component was as follows. The blending ratio of the acrylic resin was 25% by mass of the total amount of the polyvinyl chloride resin and the acrylic resin. Furthermore, the blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.

<Example 8 >
In place of the fluorescent pigment, 1 part by mass of sodium sulfonated styrene-divinylbenzene copolymer as the third resin and C.I. I. A non-aqueous inkjet ink was produced in the same manner as in Example 7 except that 3.5 parts by mass of Disperse Yellow 82 was added separately.

The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
<Example 9 >
Instead of diethylene glycol ethyl methyl ether (2EG-EM) as the first organic solvent, an amide solvent represented by the above formula (2) [Ecamide (registered trademark) M100 manufactured by Idemitsu Kosan Co., Ltd., molecular weight: 131 .2, Boiling point: 216 ° C.] was prepared in the same manner as in Example 7 except that the same amount was blended.

The blending ratio of the polyalkylene glycol alkyl ethers was 78% by mass of the total amount of the organic solvent.
<Example 10 >
Example except that diethylene glycol monoethyl ether (2EG-1E) as the third organic solvent was not blended and the blending amount of diethylene glycol diethyl ether (2EG-2E) as the second organic solvent was 61 parts by mass In the same manner as in Example 7 , a non-aqueous inkjet ink was produced.

The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
<Comparative Example 11 >
In place of the fluorescent pigment, C.I. I. A non-aqueous inkjet ink was produced in the same manner as in Example 7 except that 3.5 parts by mass of Disperse Yellow 82 was added.

The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
<Comparative example 12 >
A fluorescent pigment and diethylene glycol diethyl ether (2EG-2E) are mixed while cooling with a chiller so that the fluorescent pigment does not dissolve, and a dispersion in which the fluorescent pigment is not dissolved is prepared. A non-aqueous inkjet ink was produced in the same manner as in Example 7 except that it was added to the binder resin solution.

The blending ratio of the polyalkylene glycol alkyl ethers was 100% by mass of the total amount of the organic solvent.
<Comparative example 13 >
32 parts by weight the amount of the amide-based Solvent was produced non-aqueous inkjet ink in the same manner as in Example 9 except that the 44 parts by weight in total amount of diethylene glycol diethyl ether (2EG-2E).

The blending ratio of the polyalkylene glycol alkyl ethers was 64.8% by mass of the total amount of the organic solvent.
For the non-aqueous inkjet inks of the above Examples and Comparative Examples, the above sticking test, peeling test, storage stability test, fixing test, and the following fluorescence density evaluation and ejection stability test were performed.

<Fluorescence density evaluation>
The non-aqueous inkjet ink of each of the above Examples and Comparative Examples was used on the surface of a polyvinyl chloride tarpaulin using a wire bar (doctor 0.1, wire having a diameter of 0.1 mm wrapped around a metal rod). After coating and drying, spectral reflectance and OD value at a wavelength of 450 nm were measured using a handheld spectral color difference meter NF-999 manufactured by Nippon Denshoku Industries Co., Ltd. The fluorescence concentration was evaluated according to the following criteria.

X: There was no maximum value of spectral reflectance between wavelengths of 500 to 550 nm, or the OD value at a wavelength of 450 nm was less than 0.9. Poor fluorescence density.
(Triangle | delta): There existed the maximum value of spectral reflectance in wavelength 500-550 nm, and OD value in wavelength 450nm was 0.9 or more and less than 1.1. Normal fluorescence concentration level.
A: There was a maximum value of spectral reflectance between wavelengths of 500 to 550 nm, and the OD value at a wavelength of 450 nm was 1.1 or more and less than 1.3. Good fluorescence density.

A: There was a maximum value of spectral reflectance between wavelengths of 500 to 550 nm, and the OD value at a wavelength of 450 nm was 1.3 or more and less than 1.5. Fluorescence density is even better.
(Double-circle): There existed the maximum value of spectral reflectance in wavelength 500-550nm, and OD value in wavelength 450nm was 1.5 or more. Very good fluorescence density.
<Discharge stability test>
Using a piezo-type inkjet printer, a non-aqueous inkjet ink of each of the above examples and comparative examples was used to print a 1-point ruled line on the surface of the polyvinyl chloride tarpaulin, and the state was observed. The stability of ejection from the nozzles of an inkjet printer was evaluated as a standard.

○: No fading was observed on the ruled line. Good discharge stability.
X: Blur was seen in the ruled lines throughout the printing. Discharge stability is poor.
The above results are shown in Tables 7 and 8.

From the results of Comparative Example 11 in Table 8, when only a fluorescent dye is blended as a colorant, the ejection stability from the nozzles of the ink jet printer is good, but most of the fluorescent dye is made of polyvinyl chloride. It turned out that it moved from the surface of tarpaulin to the inside, and the fluorescence density of printing became insufficient.
Moreover, from the result of Comparative Example 12 , when a fluorescent pigment containing a fluorescent dye and a third resin as a colorant is used and dispersed without being dissolved in an organic solvent, the dispersed fluorescent pigment is aggregated. Thus, it was found that the storage stability is lowered and the ejection stability is lowered.

Furthermore, from the result of Comparative Example 13 , as the organic solvent, a compound having a blending ratio of polyalkylene glycol alkyl ethers of less than 70% by mass was used, and a fluorescent pigment was used as a colorant. Although the discharge stability is improved when completely dissolved, the fluorescent dye is mostly composed of polyvinyl chloride tarpaulin although it contains the third resin derived from the fluorescent pigment. It turned out from the surface to the inside that the fluorescence density of printing becomes insufficient. In addition, the storage stability was reduced.

On the other hand, from the results of Examples 7 to 10 in Table 7, as the organic solvent, a polyalkylene glycol alkyl ether having a blending ratio of 70% by mass or more was used, and a fluorescent pigment was used as a colorant. When it is completely dissolved in an organic solvent, or when a fluorescent dye and a third resin are used in combination, the migration of the fluorescent dye is suppressed while improving storage stability and ejection stability. It was found that most of the residue could remain on the surface of the polyvinyl chloride tarpaulin, and the fluorescent density of printing could be improved.

From the results of Examples 7 to 10 , considering that the fluorescent density of the printing is further improved, as the organic solvent, a polyalkylene glycol alkyl ether compounding ratio of 100% is used, It is preferable to use the first to third organic solvents in combination as the polyalkylene glycol alkyl ethers, and it is preferable to use a fluorescent pigment as a colorant and completely dissolve it in the organic solvent. I understood.

Claims (3)

A non-aqueous inkjet ink for printing on the surface of a medium comprising a colorant, a binder resin, and an organic solvent, and at least a surface layer comprising a polyvinyl chloride resin, wherein the binder resin is a polymer in advance. formulated, the glass transition temperature Tg of 60 ° C. or higher, at 95 ° C. or less, and a weight average molecular weight Mw of 50,000 or more, in combination with 140,000 following acrylic resins, and polyvinyl chloride resins, the acryl The blending ratio of the resin is 10% by mass or more and 35% by mass or less of the total amount of the polyvinyl chloride resin and the acrylic resin, and as the organic solvent , are only polyalkylene glycol alkyl ethers used? Or the polyalkylene glycol alkyl ethers and the formula (1):

[Wherein R ¹ , R ² , and R ³ represent the same or different alkyl groups. ]
A non-aqueous inkjet ink , wherein the amide solvent represented by the formula (1) is used in combination such that the blending ratio of the polyalkylene glycol alkyl ether is 70% by mass or more of the total amount of the organic solvent. The colorant is a fluorescent dye, and also contains a third resin that is soluble in the organic solvent and has a function of suppressing the transfer of the fluorescent dye from the surface of the medium to the inside. non-aqueous inkjet ink according to 1. An ink set comprising a plurality of non-aqueous inkjet inks, wherein the non-aqueous inkjet ink of at least one of the plurality of colors is the non-aqueous inkjet ink according to claim 1 or 2. Ink set.