JP7371265B2 - Pre-treatment liquid and ink set for non-permeable substrates - Google Patents

Description

The present disclosure relates to a pretreatment liquid for non-permeable substrates, an ink set, an image recording method, an image recording material, a recording medium, and a method for manufacturing the same.

2. Description of the Related Art Conventionally, regarding image recording on non-permeable substrates such as plastic films, techniques for recording images using ink and pretreatment liquid have been known. The pretreatment liquid is also called a precoat liquid.
For example, Patent Document 1 describes a precoat agent used to form a precoat layer that receives ink for forming an image by an inkjet method, which includes water, a cationic resin having a polyurethane structure, and two or more identical functional groups. A precoating agent is disclosed that includes an organic acid having a group and a crosslinking agent capable of reacting with the functional group. The precoating agent described in Patent Document 1 can be formed on non-absorbent recording media such as nylon (Ny), polyethylene terephthalate (PET), polypropylene (PP, especially OPP), regardless of the material of the recording medium. The purpose of this method is to provide a coating film and an image formed thereafter with high durability, and to improve the quality of the formed image.
Further, Patent Document 2 describes a pretreatment liquid for non-permeable substrates that suppresses the transfer of components contained in the pretreatment liquid from the image recording surface to a non-contact body and provides fine images. contains water, a resin, and an organic acid, the ratio of the content of the resin to the content of the organic acid is more than 0 and less than 4 on a mass basis, and the organic acid is a polyhydric carboxylic acid having a specific structure. A pretreatment liquid for non-permeable substrates is disclosed.

International Publication No. 2017/013984 International Publication No. 2019/235141

However, when producing an image recording material or a recording medium using a pretreatment liquid containing water and a carboxylic acid, precipitates may occur in the resulting image recording material or recording medium. The precipitate is considered to be a precipitate of carboxylic acid.
As a method of suppressing the generation of precipitates, a method of using a highly hydrophilic carboxylic acid (that is, a low ClogP) as the carboxylic acid in the pretreatment liquid can be considered. However, studies conducted by the present inventors have revealed that, in the case of this method, blocking may occur in the resulting image recording material or recording medium.

An object of one aspect of the present disclosure is to provide a pretreatment liquid for a non-permeable substrate, an ink set, and an image recording medium that can produce an image recording material or a recording medium in which the occurrence of precipitates and blocking are suppressed. It is an object of the present invention to provide a recording method, and an image recording material and recording medium in which the generation of precipitates and blocking are suppressed.

Specific means for solving the problem include the following aspects.
<1> A pretreatment liquid for non-permeable substrates containing water and three or more types of carboxylic acids,
A pretreatment liquid for non-permeable substrates, in which the content of a carboxylic acid having a ClogP of less than −1.00 is 2.0% by mass or less based on the total amount of the pretreatment liquid for non-permeable substrates.
<2> The non-penetrating substrate according to <1>, wherein the total content of the three or more carboxylic acids is 5.0% by mass to 13.0% by mass based on the total amount of the pretreatment liquid for non-penetrating substrates. Pre-treatment liquid for synthetic substrates.
<3> The pretreatment liquid for non-permeable substrates according to <1> or <2>, wherein the weight average ClogP of the three or more types of carboxylic acids is 0.50 or less.
<4> The pretreatment liquid for a non-permeable substrate according to any one of <1> to <3>, wherein the weight average ClogP of the three or more types of carboxylic acids is -1.00 or more.
<5> The pretreatment liquid for a non-permeable substrate according to any one of <1> to <4>, wherein the three or more carboxylic acids include two or more polyhydric carboxylic acids.
<6> Three or more carboxylic acids,
a polycarboxylic acid A1 having a ClogP of -1.00 or more and less than -0.50;
Polyvalent carboxylic acid A2, which is a polyvalent carboxylic acid whose ClogP is -0.50 or more and -0.10 or less,
Polyvalent carboxylic acid A3, which is a polyvalent carboxylic acid whose ClogP is more than −0.10 and less than or equal to 0.50;
The pretreatment liquid for non-permeable substrates according to any one of <1> to <5>, comprising:
<7> The content mass of polyvalent carboxylic acid A1, which is a polyvalent carboxylic acid whose ClogP is -1.00 or more and less than -0.50, is [A1],
The content mass of polyvalent carboxylic acid A2, which is a polyvalent carboxylic acid whose ClogP is -0.50 or more and -0.10 or less, is [A2],
When the content mass of polyvalent carboxylic acid A3, which is a polyvalent carboxylic acid whose ClogP is more than -0.10 and 0.50 or less, is [A3],
The pretreatment liquid for non-permeable substrates according to any one of <1> to <6>, wherein the [A2]/([A1]+[A3]) ratio is 0.5 to 5.0.
<8> The pretreatment liquid for non-permeable substrates according to any one of <1> to <7>, further containing a resin.
<9> The pretreatment liquid for non-permeable substrates according to <8>, wherein the resin contains resin particles.
<10> The pretreatment liquid for non-permeable substrates according to any one of <1> to <9>,
an ink containing water and a colorant;
An ink set with.
<11> Forming a layer by applying the pretreatment liquid for non-permeable substrates according to any one of <1> to <9> on the non-permeable substrate;
a step of recording an image by applying ink containing a colorant and water to a part of the layer;
An image recording method comprising:
<12> Non-permeable base material,
A layer disposed on an impermeable substrate and formed from the impermeable substrate pretreatment liquid according to any one of <1> to <9>;
an image containing a colorant disposed on a portion of the layer;
An image recording material comprising:
<13> A recording medium comprising the step of applying the pretreatment liquid for non-permeable substrates according to any one of <1> to <9> on an impermeable substrate to form a layer. Production method.
<14> Non-permeable base material,
A layer disposed on an impermeable substrate and formed from the impermeable substrate pretreatment liquid according to any one of <1> to <9>;
A recording medium comprising:

According to one aspect of the present disclosure, there is provided a pretreatment liquid for a non-permeable substrate, an ink set, and an image recording medium that can produce an image recording material or a recording medium in which the occurrence of precipitates and blocking are suppressed. A recording method, and an image recording material and recording medium in which generation of precipitates and blocking are suppressed are provided.

1 is a schematic configuration diagram showing an example of an image recording device suitable for implementing an image recording method according to an example of the present disclosure. FIG. 3 is a diagram conceptually showing a character image used for image quality evaluation in an example. FIG. 3 is a diagram for explaining details of image quality evaluation criteria in an example.

In the present disclosure, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as lower and upper limits.
In the present disclosure, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, the amount of each component in the composition means the total amount of the multiple substances present in the composition. do.
In the numerical ranges described step by step in this disclosure, the upper limit or lower limit described in a certain numerical range may be replaced with the upper limit or lower limit of another numerical range described step by step, Further, the values may be replaced with the values shown in the examples.
In the present disclosure, the term "step" is included not only in an independent step but also in the case where the intended purpose of the step is achieved even if the step cannot be clearly distinguished from other steps.
In this disclosure, combinations of preferred aspects are more preferred aspects.

In the present disclosure, a pretreatment liquid for a non-permeable substrate means a pretreatment liquid applied to a non-permeable substrate.
The pretreatment liquid for non-permeable substrates can be applied to the non-permeable substrate prior to ink, for example, when recording an image on the non-permeable substrate using ink.
Further, the pretreatment liquid for impermeable substrates can also be used for manufacturing a recording medium that includes a layer derived from the pretreatment liquid for impermeable substrates on the impermeable substrate. The obtained recording medium is used to record an image by applying ink onto the layer of the recording medium.

In the present disclosure, a layer derived from a pretreatment liquid for a nonpermeable substrate means a layer formed by applying a pretreatment liquid for a nonpermeable substrate on a nonpermeable substrate.
Below, the pretreatment liquid for non-permeable substrates may be simply referred to as "pretreatment liquid." A layer derived from a pretreatment liquid for non-permeable substrates may simply be referred to as a "layer derived from a pretreatment liquid."

[Pre-treatment liquid for non-permeable substrates]
The pretreatment liquid of the present disclosure (i.e., the pretreatment liquid for non-permeable substrates) contains water and three or more types of carboxylic acids, and the content of the carboxylic acid whose ClogP is less than -1.00. is 2.0% by mass or less based on the total amount of the pretreatment liquid for non-permeable substrates.

According to the pretreatment liquid of the present disclosure, it is possible to produce an image recording material or a recording medium in which the generation of precipitates and blocking are suppressed.
Specifically, the pretreatment liquid of the present disclosure is applied on a non-permeable substrate to form a layer, and an ink containing a colorant and water is applied to a part of the formed layer to record an image. By doing so, it is possible to produce an image recording material in which the generation of precipitates and blocking are suppressed.
Further, by applying the pretreatment liquid of the present disclosure to form a layer on a non-permeable substrate, a recording medium in which generation of precipitates and blocking are suppressed can be manufactured.
The reason why the above effects are achieved is presumed as follows.

When producing an image recording material or a recording medium using a pretreatment liquid containing water and a carboxylic acid, precipitates may occur in the resulting image recording material or recording medium. The precipitates are thought to be mainly carboxylic acid precipitates.
As a method of suppressing the generation of precipitates, a method of using a highly hydrophilic carboxylic acid (that is, a low ClogP) as the carboxylic acid in the pretreatment liquid can be considered.
However, studies conducted by the present inventors have revealed that, in the case of this method, blocking may occur in the resulting image recording material or recording medium. Here, blocking refers to when an object to be contacted (for example, a non-permeable base material, an image recording object, a recording medium, etc.) is placed on the pretreatment liquid applied surface of an image recording object or a recording medium. This refers to the phenomenon in which objects to be contacted stick to the surface to which the pretreatment liquid is applied.
The pretreatment liquid of the present disclosure can suppress the generation of precipitates by containing three or more types of carboxylic acids. The reason for this is thought to be that the inclusion of three or more types of carboxylic acids makes it difficult for the carboxylic acids to precipitate.
Furthermore, in the pretreatment liquid of the present disclosure, a carboxylic acid with a ClogP of less than -1.00 is not contained, or even if it is included, the content is limited to 2.0% by mass or less based on the total amount of the pretreatment liquid. By doing so, it is possible to suppress the occurrence of blocking.
According to the pretreatment liquid of the present disclosure, it is considered that the generation of precipitates and blocking can be suppressed as described above.

<Non-permeable base material>
As described above, the pretreatment liquid for impermeable substrates of the present disclosure is a pretreatment liquid applied to impermeable substrates.

In this disclosure, non-permeable substrates are defined as per ASTM test method ASTM D570 (1988
) and has a water absorption rate (unit: mass %, measurement time: 24 hours) of less than 0.2.

There are no particular restrictions on the impermeable base material, but a resin base material is preferred.
The resin base material is not particularly limited, and examples thereof include thermoplastic resin base materials.
Examples of the resin base material include base materials formed from thermoplastic resin into a sheet or film shape.
As the resin base material, a base material containing polypropylene, polyethylene terephthalate, nylon, polyethylene, or polyimide is preferable.

The resin base material may be a transparent resin base material or a colored resin base material.
Here, transparent means that the transmittance of visible light with a wavelength of 400 nm to 700 nm is 80% or more (preferably 90% or more).

Although the shape of the resin base material is not particularly limited, it is preferably a sheet-like resin base material, and more preferably a sheet-like resin base material that can be rolled up to form a roll.
The thickness of the resin base material is preferably 10 μm to 200 μm, more preferably 10 μm to 100 μm.

The resin base material may be surface-treated from the viewpoint of improving surface energy.
Surface treatments include, but are not limited to, corona treatment, plasma treatment, flame treatment, heat treatment, abrasion treatment, light irradiation treatment (UV treatment), flame treatment, and the like.

<Water>
The pretreatment liquid of the present disclosure contains water.
The content of water is preferably 50% by mass or more, more preferably 60% by mass or more, based on the total amount of the pretreatment liquid.
Although the upper limit of the water content depends on the amounts of other components, it is preferably 90% by mass or less, more preferably 80% by mass or less based on the total amount of the pretreatment liquid.

<Carboxylic acid>
The pretreatment liquid of the present disclosure contains three or more types of carboxylic acids.
Carboxylic acid has a function as a coagulant that coagulates components in the ink (eg, colorant, resin particles, etc.) on the non-permeable substrate. By exerting this function of the carboxylic acid, bleeding of an image recorded by applying ink onto the pretreatment liquid is suppressed.
The pretreatment liquid of the present disclosure contains three or more types of carboxylic acids, thereby suppressing the generation of precipitates on the impermeable substrate.

Further, in the pretreatment liquid of the present disclosure, the content of carboxylic acid whose ClogP is less than −1.00 is 2.0% by mass or less based on the total amount of the pretreatment liquid. This suppresses blocking as described above.
From the viewpoint of further suppressing blocking, the content of carboxylic acid whose ClogP is less than -1.00 relative to the total amount of the pretreatment liquid is preferably 1.5% by mass or less, more preferably 1.0% by mass or less. and more preferably 0.5% by mass or less. Note that the lower limit for the content of carboxylic acid whose ClogP is less than −1.00 with respect to the total amount of the pretreatment liquid is not particularly set, but is, for example, 0% by mass.

In the present disclosure, for ClogP of a carboxylic acid, a value calculated using ChemDraw (registered trademark) Professional (ver. 16.0.1.4) (manufactured by PerkinElmer) is applied.
ClogP is correlated with the degree of hydrophilicity; the smaller ClogP is, the higher the hydrophilicity is.

Each of the three or more carboxylic acids contained in the pretreatment liquid of the present disclosure may be a monocarboxylic acid (i.e., a monovalent carboxylic acid) or a polycarboxylic acid (i.e., a divalent or more carboxylic acid). carboxylic acid).
Specific examples of monocarboxylic acids and polycarboxylic acids will be described later.

The three or more carboxylic acids contained in the pretreatment liquid of the present disclosure preferably contain one or more polycarboxylic acids, and preferably contain two or more polycarboxylic acids, from the viewpoint of further suppressing image bleeding. It is more preferable that the polyhydric carboxylic acid contains three or more types of polyhydric carboxylic acids.
Furthermore, in general, the problem of precipitates is more likely to occur among carboxylic acids, particularly in polyhydric carboxylic acids. However, in the pretreatment liquid of the present disclosure, since three or more types of carboxylic acids are contained, precipitates are suppressed even when a polyhydric carboxylic acid is contained. That is, when the three or more types of carboxylic acids include one or more types of polyhydric carboxylic acids, the effect of suppressing precipitates due to the inclusion of three or more types of carboxylic acids is more effectively exhibited.
The total amount of polycarboxylic acids in the total amount of three or more carboxylic acids contained in the pretreatment liquid of the present disclosure (i.e., preferably one or more, more preferably two or more, still more preferably three or more) The proportion of the total amount of polyhydric carboxylic acids contained is preferably 50% by mass to 100% by mass, more preferably 60% by mass to 100% by mass, and still more preferably 80% by mass to 100% by mass.

The total content of carboxylic acids contained in the pretreatment liquid is preferably 4.0% to 15.0% by weight, more preferably 5.0% to 13.0% by weight, based on the total amount of the pretreatment liquid. 0% by weight, more preferably 5.0% to 12.0% by weight, and even more preferably 6.0% to 10% by weight.
When the total content of carboxylic acids is 4.0% by mass or more, image bleeding is further suppressed.
When the total content of carboxylic acids is 15.0% by mass or less, the generation of precipitates and/or blocking is further suppressed.

The weight average ClogP of the carboxylic acid contained in the pretreatment liquid is preferably 0.50 or less, more preferably 0.30 or less, and still more preferably 0.50 or less, from the viewpoint of further suppressing the generation of precipitates. It is 10 or less, more preferably 0 or less.

From the viewpoint of further suppressing blocking, the weight average ClogP of the carboxylic acid contained in the pretreatment liquid is preferably -1.00 or more, more preferably -0.80 or more, and even more preferably -0. It is 60 or more, more preferably -0.50 or more.

In this disclosure, weighted average ClogP means a weighted average value of ClogP of individual carboxylic acids.
In the present disclosure, the weighted average value is X determined by Equation 1 below.

X=ΣS _i W _i /ΣW _i … (Formula 1)

The weight average ClogP of three or more types of carboxylic acids (i.e., the ClogP of each individual carboxylic acid) _is calculated by using the following formula: X in Formula 1 is obtained by substituting ClogP of the carboxylic acid and substituting the mass fraction of the i type of carboxylic acid in the total carboxylic acids contained in the pretreatment liquid for W _i .
For example, 1% by weight of adipic acid (a carboxylic acid with a ClogP of -0.02), 5% by weight of glutaric acid (a carboxylic acid with a ClogP of -0.13), and 5% by weight of succinic acid (a carboxylic acid with a ClogP of -0.53). In the pretreatment liquid containing 2% by mass of carboxylic acid, the weight average ClogP of these three types of carboxylic acids is determined to be -0.22 by the following formula.
X
=ΣS _i W _i /ΣW _i
= [-0.02×(1/(1+5+2))+(-0.13)×(5/(1+5+2))+(-0.53)×(2/(1+5+2))]
=-0.22

From the viewpoint of further suppressing the generation of precipitates, the proportion of the total content of carboxylic acids whose ClogP is 0.50 or less in the total amount of three or more types of carboxylic acids contained in the pretreatment liquid is preferably The content is 50% by mass to 100% by mass, more preferably 60% to 100% by mass, and still more preferably 80% to 100% by mass.
From the viewpoint of further suppressing the generation of precipitates, it is preferable that all three or more types of carboxylic acids contained in the pretreatment liquid are carboxylic acids having a ClogP of 0.50 or less.

From the viewpoint of further suppressing the occurrence of blocking, the proportion of the total content of carboxylic acids whose ClogP is -1.00 or more in the total amount of three or more carboxylic acids contained in the pretreatment liquid is preferably The content is 50% by mass to 100% by mass, more preferably 60% to 100% by mass, and still more preferably 80% to 100% by mass.
From the viewpoint of further suppressing the generation of precipitates, it is preferable that all three or more types of carboxylic acids contained in the pretreatment liquid have a ClogP of -1.00 or more.

From the viewpoint of further suppressing the occurrence of precipitates and blocking, the total content of carboxylic acids whose ClogP is -1.00 or more and 0.50 or less in the total amount of three or more carboxylic acids contained in the pretreatment liquid. The amount ratio is preferably 50% to 100% by weight, more preferably 60% to 100% by weight, even more preferably 80% to 100% by weight.
From the viewpoint of further suppressing the generation of precipitates, it is preferable that all three or more types of carboxylic acids contained in the pretreatment liquid have a ClogP of −1.00 or more and 0.50 or less.

(Polyhydric carboxylic acid)
As mentioned above, it is preferable that the three or more types of carboxylic acids contained in the pretreatment liquid of the present disclosure include a polyhydric carboxylic acid.

The molecular weight of the polyvalent carboxylic acid is preferably 1000 or less, more preferably 500 or less, and even more preferably 300 or less.
The lower limit of the molecular weight of the polyvalent carboxylic acid is, for example, 60, preferably 90 or more, and more preferably 100 or more.

Examples of the polyhydric carboxylic acid include compounds represented by the following general formula 1.

In General Formula 1, l is 1 or more, m is 0 or 1, n is 1 or more, and l+m+n is 2 or more. R ₁ to R ₄ each independently represent a hydrogen atom, a hydroxyl group (OH), a carboxy group (COOH), an amino group (NH ₂ ), or an alkyl group having 1 to 4 carbon atoms.
Examples of the alkyl group having 1 to 4 carbon atoms in R ₁ to R ₄ include a methyl group, an ethyl group, a propyl group, and a butyl group.

The above R ₁ to R ₄ are each independently preferably a hydrogen atom or a carboxy group, more preferably a hydrogen atom, from the viewpoint of the cohesiveness of the ink.

l and n are preferably 1 to 3, and m is preferably 0.

In general formula 1, l+m+n is preferably 3 to 8. When l+m+n is 3 or more, the polyhydric carboxylic acid can be made more hydrophobic, and blocking can be further suppressed. When l+m+n is 8 or less, the polyhydric carboxylic acid is prevented from becoming too hydrophobic, and as a result, the generation of precipitates is further suppressed.
From the same viewpoint as above, l+m+n is more preferably 3 to 5.
Further, in the general formula 1, m is preferably 0, and when m is 0, l+n is preferably 3 to 5.

In general formula 1, it is preferable that m is 0 and R ₁ to R ₄ are hydrogen atoms.
Note that it is preferable that at least a portion of the carboxy group in the above general formula 1 is dissociated in the pretreatment liquid.

The weight average ClogP of the polyhydric carboxylic acid that may be contained in the pretreatment liquid of the present disclosure is preferably 0.50 or less, more preferably 0.30 or less, from the viewpoint of further suppressing the generation of precipitates, More preferably, it is 0.10 or less, and still more preferably 0 or less.

From the viewpoint of further suppressing blocking, the weight average ClogP of the polyhydric carboxylic acid that may be contained in the pretreatment liquid of the present disclosure is preferably -1.00 or more, more preferably -0.80 or more, and It is preferably -0.60 or more, more preferably -0.50 or more.

From the viewpoint of further suppressing the generation of precipitates, the proportion of the total content of polyvalent carboxylic acids whose ClogP is 0.50 or less in the total amount of polyvalent carboxylic acids that can be contained in the pretreatment liquid is preferably The content is 50% by mass to 100% by mass, more preferably 60% to 100% by mass, and still more preferably 80% to 100% by mass.
From the viewpoint of further suppressing the generation of precipitates, it is preferable that all polycarboxylic acids that may be contained in the pretreatment liquid have a ClogP of 0.50 or less.

From the viewpoint of further suppressing the occurrence of blocking, the proportion of the total content of polyvalent carboxylic acids whose ClogP is -1.00 or more in the total amount of polyvalent carboxylic acids that can be contained in the pretreatment liquid is preferably The content is 50% by mass to 100% by mass, more preferably 60% to 100% by mass, and still more preferably 80% to 100% by mass.
From the viewpoint of further suppressing the generation of precipitates, it is preferable that all polyvalent carboxylic acids that may be contained in the pretreatment liquid have a ClogP of -1.00 or more.

From the viewpoint of further suppressing the occurrence of precipitates and blocking, the total content of polycarboxylic acids whose ClogP is -1.00 or more and 0.50 or less in the total amount of polycarboxylic acids that can be contained in the pretreatment liquid. The amount ratio is preferably 50% to 100% by weight, more preferably 60% to 100% by weight, even more preferably 80% to 100% by weight.
From the viewpoint of further suppressing the generation of precipitates, it is preferable that all polycarboxylic acids that may be contained in the pretreatment liquid have a ClogP of −1.00 or more and 0.50 or less.

The total content of polyhydric carboxylic acids that can be contained in the pretreatment liquid is preferably 4.0% by mass to 15.0% by mass, more preferably 5.0% by mass to 15.0% by mass, based on the total amount of the pretreatment liquid. The content is 13.0% by weight, more preferably 5.0% to 12.0% by weight, and even more preferably 6.0% to 10% by weight.
When the total content of polyhydric carboxylic acids that can be contained in the pretreatment liquid is 4.0% by mass or more, image bleeding is further suppressed.
When the total content of polyhydric carboxylic acids that can be contained in the pretreatment liquid is 15.0% by mass or less, the generation of precipitates and/or blocking is further suppressed.

The three or more carboxylic acids contained in the pretreatment liquid of the present disclosure are, from the viewpoint of further suppressing the generation of precipitates,
a polycarboxylic acid A1 having a ClogP of -1.00 or more and less than -0.50;
Polyvalent carboxylic acid A2, which is a polyvalent carboxylic acid whose ClogP is -0.50 or more and -0.10 or less,
Polyvalent carboxylic acid A3, which is a polyvalent carboxylic acid whose ClogP is more than −0.10 and less than or equal to 0.50;
It is preferable to include.
In this preferred embodiment, each of the polycarboxylic acids A1, A2, and A3 may be one type or two or more types.

Specific examples of each of polyvalent carboxylic acid A1, polyvalent carboxylic acid A2, and polyvalent carboxylic acid A3 are shown below, but each of polyvalent carboxylic acid A1, polyvalent carboxylic acid A2, and polyvalent carboxylic acid A3 , but is not limited to the following specific examples.

Examples of the polyhydric carboxylic acid A1 include succinic acid (ClogP=-0.53) and malonic acid (ClogP=-0.71).

Examples of the polycarboxylic acid A2 include glutaric acid (ClogP=-0.13), maleic acid (ClogP=-0.17), itaconic acid (ClogP=-0.33), fumaric acid (ClogP=-0 .17) etc.

Examples of the polycarboxylic acid A3 include adipic acid (ClogP=-0.02) and mesaconic acid (ClogP=0.14).
As the three or more types of carboxylic acids contained in the pretreatment liquid, it is preferable that at least one type selected from the group consisting of adipic acid, glutaric acid, maleic acid, succinic acid or malonic acid is included, and two or more types are preferably included. More preferably, the three or more carboxylic acids include only carboxylic acids selected from these groups.

Let the total content mass of polycarboxylic acid A1 be [A1],
Let the total content mass of polycarboxylic acid A2 be [A2],
When the total content mass of polyhydric carboxylic acid A3 is [A3],
The [A2]/([A1]+[A3]) ratio is preferably 0.5 to 5.0, more preferably 0.5 to 4.0, even more preferably 0.5 to 3. It is 0.
When the [A2]/([A1]+[A3]) ratio is 0.5 to 5.0, the generation of precipitates is further suppressed.
In these preferred embodiments, it is not necessarily necessary to include all of the polyhydric carboxylic acids A1 to A3. Even when one or two of the polyhydric carboxylic acids A1 to A3 are included, if the [A2]/([A1]+[A3]) ratio is within the above preferred range, the above preferred embodiment is applied. Included.

The total content of polyvalent carboxylic acid A1, polyvalent carboxylic acid A2, and polyvalent carboxylic acid A3 (hereinafter also referred to as "total content of polyvalent carboxylic acids A1 to A3") is based on the total amount of the pretreatment liquid. , preferably 4.0% by mass to 15.0% by mass, more preferably 5.0% to 13.0% by mass, still more preferably 5.0% to 12.0% by mass. , more preferably 6.0% by mass to 10% by mass.
When the total content of polyhydric carboxylic acids A1 to A3 is 4.0% by mass or more, image bleeding is further suppressed.
When the total content of polyhydric carboxylic acids A1 to A3 is 15.0% by mass or less, the generation of precipitates is further suppressed.

The three or more carboxylic acids contained in the pretreatment liquid are polyvalent carboxylic acids other than polyvalent carboxylic acids A1 to A3 (i.e., polyvalent carboxylic acids whose ClogP is less than -1.00 or more than 0.50). (acid) may be included.

Other polycarboxylic acids include pimelic acid (ClogP=0.51), propanetricarboxylic acid (ClogP=-1.08), malic acid (ClogP=-1.52), oxalic acid (ClogP=-1. 75), citric acid (ClogP=-2.00), tartaric acid (ClogP=-3.22), polyacrylic acid, chelidamic acid (ClogP=1.44), and the like.

The proportion of the total content of polyhydric carboxylic acids A1 to A3 in the total amount of carboxylic acids contained in the pretreatment liquid is preferably 50% by mass to 100% by mass, more preferably 60% by mass to 100% by mass. It is mass %, more preferably 80 mass % to 100 mass %.

(monocarboxylic acid)
The three or more carboxylic acids contained in the pretreatment liquid of the present disclosure may include one or more monocarboxylic acids.
Monocarboxylic acids can also function as flocculants that flocculate components in the ink (eg, colorants, resin particles, etc.).
Monocarboxylic acids include butyric acid (ClogP=0.86), acetic acid (ClogP=-0.19), lactic acid (ClogP=-0.73), glycolic acid (ClogP=-1.04), and pyrrolidonecarboxylic acid (ClogP=-1.04). ClogP=-1.15), comanic acid (ClogP=-0.29), 2-furancarboxylic acid (ClogP=1.06), and 4-pyridinecarboxylic acid (ClogP=0.78).

<Acids other than carboxylic acids>
The pretreatment liquid may contain at least one type of acid other than carboxylic acid.
Acids other than carboxylic acids can also function as flocculants that flocculate components in the ink (eg, colorants, resin particles, etc.).
Examples of acids other than carboxylic acids include sulfonic acids (eg, benzenesulfonic acid), phosphoric acids, and the like.

The proportion of carboxylic acid in the total amount of acids contained in the pretreatment liquid is preferably 50% by mass to 100% by mass, more preferably 60% by mass to 100% by mass, and even more preferably 80% by mass. ~100% by mass.

<Flocculants other than acids>
The pretreatment liquid of the present disclosure may contain at least one type of aggregating agent other than acid as an aggregating agent that aggregates components in the ink (for example, colorant, resin particles, etc.).
Examples of flocculants other than acids include polyvalent metal salts, metal complexes, water-soluble cationic polymers, and the like.
For flocculants other than acids, publicly known documents such as International Publication No. 2019/004485, International Publication No. 2019/150878, and International Publication No. 2019/163581 can be referred to as appropriate.

When the pretreatment liquid of the present disclosure contains a flocculant other than carboxylic acid, the content of carboxylic acid in the entire flocculant is preferably 50% by mass to 100% by mass, more preferably 60% by mass to The content is 100% by mass, more preferably 80% by mass to 100% by mass.

<Resin>
Preferably, the pretreatment liquid of the present disclosure contains at least one resin.
By containing the resin in the pretreatment liquid, the adhesion of the image to the non-permeable substrate is ensured.
There is no particular restriction on the resin that can be contained in the pretreatment liquid, and known resins may be used.

The glass transition temperature (Tg) of the resin that can be contained in the pretreatment liquid is preferably 0°C to 120°C, more preferably 10°C to 80°C, even more preferably 15°C to 60°C, and even more preferably 20°C to 60°C. More preferred.

In this disclosure, the glass transition temperature of a resin means a value measured using differential scanning calorimetry (DSC).
The specific measurement of the glass transition temperature is performed according to the method described in JIS K 7121 (1987) or JIS K 6240 (2011).
The glass transition temperature in the present disclosure is an extrapolated glass transition initiation temperature (hereinafter sometimes referred to as Tig).
The method for measuring the glass transition temperature will be explained in more detail.
To determine the glass transition temperature, hold the device at a temperature approximately 50°C lower than the expected glass transition temperature of the resin particles until it stabilizes, then heat at a heating rate of 20°C/min to a temperature lower than the temperature at which the glass transition has completed. Heat to about 30° C. higher temperature and generate differential thermal analysis (DTA) or DSC curves.
The extrapolated glass transition onset temperature (Tig), that is, the glass transition temperature in the present disclosure, is defined as the straight line extending the baseline on the low temperature side to the high temperature side in the DTA curve or DSC curve, and the curve of the step-like change part of the glass transition. It is determined as the temperature at the intersection with the tangent line drawn at the point where the slope is maximum.

Further, in the present disclosure, when the pretreatment liquid contains two or more types of resins, the glass transition temperature of the resin contained in the pretreatment liquid is the weighted average of the glass transition temperatures of the resins contained in the pretreatment liquid. means value. Specifically, in the above-mentioned formula 1, the glass transition temperature of the i type of resin (i represents an integer of 1 or more) contained in the pretreatment liquid is substituted for S _i , and the pretreatment liquid is substituted for W _i . Calculate the weighted average value of the glass transition temperature of the resin contained in the pretreatment liquid as X in Formula 1 by substituting the mass fraction of the i type resin particles (C) in the total resin contained in can do.

Examples of resins that can be contained in the pretreatment liquid include urethane resins, polyester resins, acrylic resins, amide resins, urea resins, polycarbonate resins, olefin resins, styrene resins, polyalkylene glycol resins, polyvinyl alcohol resins, and the like.
The pretreatment liquid may contain only one type of resin, or may contain two or more types of resin.

Here, the acrylic resin is at least one selected from the group consisting of acrylic acid, acrylic acid derivatives (e.g., acrylic esters, etc.), methacrylic acid, and methacrylic acid derivatives (e.g., methacrylic esters, etc.). It means a polymer (homopolymer or copolymer) of raw material monomers containing.
That is, the concept of acrylic resin in the present disclosure includes not only resins containing structural units derived from acrylic acid or derivatives thereof, but also resins containing structural units derived from methacrylic acid or derivatives thereof.

The weight average molecular weight (Mw) of the resin that can be contained in the pretreatment liquid is preferably 1,000 to 300,000, more preferably 2,000 to 200,000, and even more preferably 5,000 to 100,000.

In the present disclosure, weight average molecular weight (Mw) means a value measured by gel permeation chromatography (GPC) unless otherwise specified.
For measurement by gel permeation chromatography (GPC), HLC (registered trademark)-8020GPC (Tosoh Corporation) was used as the measuring device, and TSKgel (registered trademark) Super Multipore HZ-H (4.6 mm ID x Three 15 cm bottles (manufactured by Tosoh Corporation) are used, and THF (tetrahydrofuran) is used as the eluent. The measurement conditions are as follows: sample concentration is 0.45% by mass, flow rate is 0.35ml/min, sample injection amount is 10μl, and measurement temperature is 40°C, using an RI detector.
The calibration curve is based on Tosoh Corporation's "Standard Sample TSK standard, polystyrene": "F-40", "F-20", "F-4", "F-1", "A-5000", "A -2500'', ``A-1000'', and 8 samples of ``n-propylbenzene''.

The resin that can be contained in the pretreatment liquid may be a water-soluble resin or a resin particle (ie, a water-insoluble resin).
In this disclosure,
"Water-insoluble" in a water-insoluble resin means a property in which the amount dissolved in 100 g of water at 25 ° C. is less than 1.0 g (more preferably less than 0.5 g),
"Water-soluble" in a water-soluble resin means a property in which the amount dissolved in 100 g of water at 25° C. is 1.0 g or more.

Specific examples of water-soluble resins include polyalkylene glycol resins, polyvinyl alcohol resins, and the like.
Specific examples of water-insoluble resins include urethane resins, polyester resins, acrylic resins, amide resins, urea resins, polycarbonate resins, olefin resins, styrene resins, and the like.

The resin that can be contained in the pretreatment liquid preferably contains resin particles from the viewpoint of further suppressing blocking and image bleeding.
In this case, the resin particles occupying the entire resin in the pretreatment liquid are preferably 50% to 100% by mass, more preferably 60% to 100% by mass, and even more preferably 80% to 100% by mass. %.

The volume average particle size of the resin particles is preferably 1 nm to 300 nm, more preferably 3 nm to 200 nm, and even more preferably 5 nm to 150 nm.

In the present disclosure, the volume average particle diameter means a value measured by a laser diffraction/scattering particle size distribution analyzer.
Examples of the measuring device include a particle size distribution measuring device "Microtrack MT-3300II" (manufactured by Nikkiso Co., Ltd.).

Preferable resin particles that can be contained in the pretreatment liquid are at least one selected from the group consisting of acrylic resin particles, urethane resin particles, polyester resin particles, and composite particles containing an acrylic resin and a polyester resin.
Regarding these preferable resin particles, known documents such as International Publication No. 2019/150878 and International Publication No. 2019/163581 can be appropriately referred to.

When preparing a pretreatment liquid containing resin particles, a commercially available aqueous dispersion of resin particles may be used.
Examples of commercially available aqueous dispersions of acrylic resin particles include EM57DOC (manufactured by Daicel Finechem).
As the aqueous dispersion of acrylic resin particles, an aqueous dispersion of acrylic resin particles may be selected from the aqueous dispersions of water-insoluble resin particles described in International Publication No. 2017/163738.
Examples of commercially available aqueous dispersions of polyester resin particles include Eastek 1100, Eastek 1200 (manufactured by Eastman Chemical), Pluscoat RZ570, Pluscoat Z687, Pluscoat Z565, Pluscoat RZ570, and Pluscoat Z690 (all manufactured by Eastman Chemical). (manufactured by Kagaku Kogyo Co., Ltd.), Vylonal MD1200 (manufactured by Toyobo Co., Ltd.), and the like.
Examples of commercially available aqueous dispersions of composite particles containing an acrylic resin and a polyester resin include Pesresin A615GE and Pesresin A613GE (manufactured by Takamatsu Yushi Co., Ltd.).
Examples of commercially available urethane resin particles include the "Superflex" series (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.).

The resin that can be contained in the pretreatment liquid is preferably an anionic resin from the viewpoint of further suppressing blocking and image bleeding.
Anionic resin means a resin containing an anionic group.
The anionic group is not particularly limited, but is preferably a carboxy group or a sulfo group, more preferably a sulfo group.
The amount of anionic group is not particularly limited, and is preferably 0.001 mol to 1.0 mol, more preferably 0.01 mol to 0.5 mol per 100 g of resin.

When the pretreatment liquid contains a resin, the ratio of the content mass of the resin to the total content mass of three or more types of carboxylic acids (hereinafter also referred to as "content mass ratio [resin/carboxylic acid]") is preferably 0. It is 3 to 3.5, more preferably 0.6 to 3.5, even more preferably 0.8 to 3.3, and still more preferably 1.0 to 3.0.
When the content mass ratio [resin/carboxylic acid] is 0.3 or more, the adhesion of the layer derived from the pretreatment liquid to the non-permeable substrate is further improved.
Further, generally, when the content mass ratio [resin/carboxylic acid] is 0.3 or more, carboxylic acid precipitates tend to occur easily, but according to the pretreatment liquid of the present disclosure, By containing three or more types of carboxylic acids, the generation of carboxylic acid precipitates is suppressed even when the content mass ratio [resin/carboxylic acid] is 0.3 or more.
Further, when the content mass ratio [resin/carboxylic acid] is 3.5 or less, image blurring is further suppressed.

When the pretreatment liquid contains a resin, the content of the resin relative to the total amount of the pretreatment liquid is preferably 1.0% by mass to 30.0% by mass, more preferably 2.0% by mass to 20.0% by mass. % by mass, more preferably 3.0% by mass to 15.0% by mass, still more preferably 5.0% by mass to 15.0% by mass.

<Water-soluble solvent>
The pretreatment liquid of the present disclosure may contain at least one water-soluble solvent.

In the present disclosure, "water-soluble" in a water-soluble solvent means a property of dissolving 1 g or more in 100 g of water at 25°C.
"Water-soluble" in a water-soluble solvent preferably means a property of dissolving 3 g or more (more preferably 10 g or more) in 100 g of water at 25°C.

As the water-soluble solvent, any known water-soluble solvent can be used without particular limitation.
Examples of water-soluble solvents include glycerin, 1,2,6-hexanetriol, trimethylolpropane, alkanediols (e.g., ethylene glycol, propylene glycol (1,2-propanediol), 1,3-propanediol, , 3-butanediol, 1,4-butanediol, 2-butene-1,4-diol, 2-ethyl-1,3-hexanediol, 2-methyl-2,4-pentanediol, 1,2-octane diol, 1,2-hexanediol, 1,2-pentanediol, 4-methyl-1,2-pentanediol, etc.), polyalkylene glycol (for example, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, Polyhydric alcohols such as propylene glycol, polyoxyethylene polyoxypropylene glycol, etc.);
Polyhydric alcohol ethers such as polyalkylene glycol ethers (e.g., diethylene glycol monoalkyl ether, triethylene glycol monoalkyl ether, tripropylene glycol monoalkyl ether, polyoxypropylene glyceryl ether, etc.);
Alkyl alcohols having 1 to 4 carbon atoms, glycol ethers, 2-pyrrolidone, and N-methyl-2-pyrrolidone described in paragraph 0116 of JP-A No. 2011-42150;
etc.
Among these, polyhydric alcohols or polyhydric alcohol ethers are preferred, and alkanediols, polyalkylene glycols, or polyalkylene glycol ethers are more preferred, from the viewpoint of suppressing component transfer.

(surfactant)
The pretreatment liquid of the present disclosure may include at least one surfactant.
Surfactants can be used as surface tension modifiers or antifoaming agents. Examples of the surface tension modifier or antifoaming agent include nonionic surfactants, cationic surfactants, anionic surfactants, betaine surfactants, and the like. Among these, nonionic surfactants or anionic surfactants are preferred from the viewpoint of the aggregation rate of the ink.

Preferred surfactants include acetylene glycol surfactants, which are a type of nonionic surfactants.
As the acetylene glycol surfactant, for example, the acetylene glycol surfactants described in paragraphs 0070 to 0080 of International Publication No. 2017/149917 can be used.
Examples of acetylene glycol surfactants include:
a polyalkylene oxide adduct (preferably a polyethylene oxide adduct) of 2,4,7,9-tetramethyl-5-decyne-4,7-diol,
a polyalkylene oxide adduct (preferably a polyethylene oxide adduct) of 3,6-dimethyl-4-octyne-3,6-diol,
a polyalkylene oxide adduct (preferably a polyethylene oxide adduct) of 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol,
Polyalkylene oxide adduct (preferably polyethylene oxide adduct) of 2,5-dimethyl-3-hexyne-2,5-diol
etc.
Commercially available acetylene glycol surfactants include the Surfynol series (for example, Surfynol 420, Surfynol 440, Surfynol 465, Surfynol 485) manufactured by Air Products Co., Ltd. or Nissin Chemical Industry Co., Ltd. Fin series (for example, Olfine E1010, Olfine E1020), Dynor series (for example, Dynor 604), etc.; Acetylenol made by Kawaken Fine Chemicals, etc.; and the like.
Commercial products of acetylene glycol surfactants are also provided by Dow Chemical Company, General Aniline Company, and others.

As surfactants, those listed in JP-A-59-157636, pages 37-38 and Research Disclosure No. 308119 (1989) as surfactants. Also included are fluorine (alkyl fluoride) surfactants, silicone surfactants, etc., which are described in JP-A No. 2003-322926, JP-A No. 2004-325707, and JP-A No. 2004-309806. .

When the pretreatment liquid of the present disclosure contains a surfactant, the content of the surfactant in the pretreatment liquid is not particularly limited, but the content may be such that the surface tension of the pretreatment liquid is 50 mN/m or less. The content is preferably 20 mN/m to 50 mN/m, more preferably 30 mN/m to 45 mN/m.
For example, when the pretreatment liquid contains a surfactant as an antifoaming agent, the content of the surfactant as an antifoaming agent is preferably 0.0001% by mass to 1% by mass based on the total amount of the pretreatment liquid. , more preferably 0.001% by mass to 0.1% by mass.

(Other ingredients)
The pretreatment liquid of the present disclosure may contain other components other than those mentioned above, if necessary.
Other components that may be contained in the pretreatment liquid include solid wetting agents, colloidal silica, inorganic salts, antifading agents, emulsion stabilizers, penetration enhancers, ultraviolet absorbers, preservatives, antifungal agents, pH adjusters, Viscosity modifiers, rust preventives, chelating agents, water-soluble polymer compounds other than water-soluble cationic polymers (for example, water-soluble polymer compounds described in paragraphs 0026 to 0080 of JP-A No. 2013-001854), etc. Examples of known additives include:

(Physical properties of pretreatment liquid)
The pH of the pretreatment liquid of the present disclosure at 25° C. is preferably 0.5 to 6.0.
When the pH of the pretreatment liquid at 25° C. is 0.5 or more, the roughness of the non-permeable base material is further reduced, and the adhesion of the image area is further improved.
When the pH of the pretreatment liquid at 25° C. is 6.0 or less, the aggregation rate is further improved, the coalescence of ink dots (ink dots) on the non-permeable substrate is further suppressed, and the roughness of the image is reduced. is further reduced.
The pH of the pretreatment liquid at 25°C is more preferably 0.5 to 5.0.
pH in the present disclosure means a value measured using a pH meter.

The viscosity of the pretreatment liquid of the present disclosure is preferably in the range of 0.5 mPa·s to 10 mPa·s, more preferably in the range of 1 mPa·s to 5 mPa·s, from the viewpoint of the aggregation rate of the ink.

The viscosity in the present disclosure is a value measured at 25° C. using a viscometer.
As the viscometer, for example, VISCOMETER TV-22 type viscometer (manufactured by Toki Sangyo Co., Ltd.) can be used.

The surface tension of the pretreatment liquid of the present disclosure is preferably 60 mN/m or less, more preferably 20 mN/m to 50 mN/m, and even more preferably 30 mN/m to 45 mN/m.
When the surface tension of the pretreatment liquid is within the above range, the adhesion between the impermeable substrate and the pretreatment liquid is improved.

The surface tension in the present disclosure is a value measured at a temperature of 25°C.
Surface tension can be measured using, for example, Automatic Surface Tentiometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.).

[Ink set]
The ink set of the present disclosure includes the pretreatment liquid of the present disclosure described above and an ink containing a colorant and water.
The ink set of the present disclosure includes applying the pretreatment liquid of the present disclosure onto a non-permeable base material, and applying ink to a part of the area on the non-permeable base material to which the pretreatment liquid has been applied. It is suitably used for image recording in the form of recording an image (for example, the image recording method of the present disclosure described below).
Since the ink set of the present disclosure includes the pretreatment liquid of the present disclosure described above, the ink set of the present disclosure provides the same effects as the effects achieved by the pretreatment liquid of the present disclosure described above. That is, according to the ink set of the present disclosure, it is possible to produce an image recording material in which the generation of precipitates and blocking are suppressed.

<Pre-treatment liquid>
The ink set of the present disclosure includes the pretreatment liquid of the present disclosure described above.
The ink set of the present disclosure may include only one type of the above-described pretreatment liquid of the present disclosure, or may include two or more types of the pretreatment liquid of the present disclosure.

<Ink>
An ink set of the present disclosure includes an ink containing a colorant and water.
The ink set of the present disclosure may include only one type of the above ink, or may include two or more types of the above ink.
According to an embodiment in which the ink set of the present disclosure includes two or more types of inks, a multicolor image can be recorded.
As for two or more types of ink,
Three types of ink consisting of cyan ink, magenta ink, and yellow ink;
Four types of ink consisting of cyan ink, magenta ink, yellow ink, and black ink;
four or more types of ink consisting of the above three types of colored inks and at least one selected from white ink, green ink, orange ink, violet ink, light cyan ink, light magenta ink, and light yellow ink;
5 or more types of ink consisting of the above 4 types of colored inks and at least one selected from white ink, green ink, orange ink, violet ink, light cyan ink, light magenta ink, and light yellow ink;
etc.
However, the two or more types of ink are not limited to these specific examples.

As the ink, inkjet ink is preferable from the viewpoint of the image quality of the recorded image.

Each component that can be contained in the ink will be explained below.

(colorant)
The ink contains at least one colorant.
The colorant is not particularly limited and any known colorant can be used, but organic pigments or inorganic pigments are preferred.

Examples of organic pigments include azo pigments, polycyclic pigments, dye chelates, nitro pigments, nitroso pigments, and aniline black. Among these, azo pigments, polycyclic pigments, and the like are more preferred.
Examples of inorganic pigments include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, and carbon black. Among these, carbon black is particularly preferred.
Preferable examples of the colorant include those described in paragraphs 0096 to 0100 of JP-A-2009-241586.

The content of the colorant is preferably 1% by mass to 25% by mass, more preferably 2% by mass to 20% by mass, and particularly preferably 2% by mass to 15% by mass, based on the total amount of the ink.

(dispersant)
The ink may contain a dispersant to disperse the colorant. The dispersant may be either a polymer dispersant or a low molecular surfactant type dispersant. Further, the polymer dispersant may be either a water-soluble dispersant or a water-insoluble dispersant.
As the dispersant, for example, the dispersants described in paragraphs 0080 to 0096 of JP-A No. 2016-145312 are preferably mentioned.

The mixing mass ratio (p:s) of the colorant (p) and the dispersant (s) is preferably in the range of 1:0.06 to 1:3, and preferably in the range of 1:0.125 to 1:2. The ratio is more preferably 1:0.125 to 1:1.5.

(water)
Ink contains water.
The water content is preferably 50% by mass or more, more preferably 60% by mass or more, based on the total amount of the ink.
The upper limit of the water content is preferably 90% by mass or less, more preferably 80% by mass or less based on the total amount of the ink, although it depends on the amounts of other components.

(resin particles)
The ink preferably contains resin particles.
This further improves the adhesion and image quality of the image.

As the resin particles, at least one of acrylic resin particles and urethane resin particles is preferable from the viewpoint of further improving image adhesion and image quality.
The meaning of the acrylic resin particles and urethane resin particles that can be contained in the ink is the same as the meaning of the acrylic resin particles and urethane resin particles that can be contained in the pretreatment liquid, as described above.

The resin particles that can be contained in the ink preferably include acrylic resin particles from the viewpoint of further improving the adhesion of images.

As the acrylic resin particles, acrylic resin particles that are self-dispersing resin particles are also preferable.
Examples of the self-dispersing resin particles include self-dispersing polymer particles described in paragraphs 0062 to 0076 of JP-A No. 2016-188345.

When the resin particles that can be contained in the ink include acrylic resin particles, the ratio of the acrylic resin particles to the resin particles that can be contained in the ink is preferably 60% by mass or more, more preferably 80% by mass or more, More preferably, it is 90% by mass or more.
When the ratio of acrylic resin particles to the resin particles that can be contained in the ink is 60% by mass or more, the adhesion of the image is further improved.

The glass transition temperature of the resin particles that can be contained in the ink is not particularly limited, but from the viewpoint of suitability for manufacturing the resin particles, it is preferably 150°C or lower, more preferably 130°C or lower.
The lower limit of the glass transition temperature of the resin particles that can be contained in the ink is not particularly limited, but is, for example, 50°C, preferably 80°C.
The method for measuring the glass transition temperature is as described above.

Further, the resin in the resin particles that may be contained in the ink is preferably a water-insoluble resin.

Further, the volume average particle diameter (P _i ) of the resin particles that can be contained in the ink is preferably 1 nm to 200 nm, more preferably 3 nm to 200 nm, and even more preferably 5 nm to 50 nm.
The method for measuring the volume average particle diameter of the resin particles is as described above.

The weight average molecular weight (Mw) of each resin in the resin particles that can be contained in the ink is preferably 1,000 to 300,000, more preferably 2,000 to 200,000, and even more preferably 5,000 to 100,000. .
The method for measuring Mw is as described above.

The resin in the resin particles that can be contained in the ink preferably has an alicyclic structure or an aromatic cyclic structure, and more preferably has an aromatic cyclic structure.
The alicyclic structure is preferably an alicyclic hydrocarbon structure having 5 to 10 carbon atoms, and a cyclohexane ring structure, a dicyclopentanyl ring structure, a dicyclopentenyl ring structure, or an adamantane ring structure is preferable.
The aromatic ring structure is preferably a naphthalene ring or a benzene ring, and more preferably a benzene ring.
The amount of the alicyclic structure or aromatic ring structure is not particularly limited, and is preferably 0.01 mol to 1.5 mol, more preferably 0.1 mol to 1 mol, per 100 g of resin.

The resin in the resin particles that may be contained in the ink is preferably an anionic resin (that is, a resin containing an anionic group).
The anionic group is not particularly limited, but is preferably a carboxy group or a sulfo group, more preferably a carboxy group.
The amount of anionic group is not particularly limited, and is preferably 0.001 mol to 1.0 mol, more preferably 0.01 mol to 0.5 mol per 100 g of resin.

The content of resin particles relative to the total amount of ink is preferably 1% by mass to 25% by mass, more preferably 2% by mass to 20% by mass, and even more preferably 3% by mass to 15% by mass. preferable.

(Water-soluble solvent)
Preferably, the ink contains at least one water-soluble solvent.
Thereby, the effect of suppressing ink drying or ink wetting can be obtained.
The water-soluble solvent that can be contained in the ink can be used, for example, as an anti-drying agent that prevents the ink from adhering to and drying at the ink ejection opening of the ejection nozzle, forming aggregates and clogging the ink.
From the viewpoint of drying suppression and wetting, the water-soluble solvent contained in the ink is preferably a water-soluble solvent having a vapor pressure lower than that of water.
Further, the boiling point of the water-soluble solvent at 1 atm (1013.25 hPa) is preferably 80°C to 300°C, more preferably 120°C to 250°C.

The anti-drying agent is preferably a water-soluble solvent having a lower vapor pressure than water.
Specific examples of such water-soluble solvents include ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, thiodiglycol, dithiodiglycol, 2-methyl-1,3-propanediol, and 1,2,6-hexanetriol. , acetylene glycol derivatives, glycerin, trimethylolpropane, and other polyhydric alcohols.
Among these, polyhydric alcohols such as glycerin and diethylene glycol are preferred as anti-drying agents.
The anti-drying agents may be used alone or in combination of two or more. The content of the anti-drying agent is preferably in the range of 10% by mass to 50% by mass based on the total amount of ink.

In addition to the above, water-soluble solvents may be used to adjust the viscosity of the ink.
Specific examples of water-soluble solvents that can be used to adjust the viscosity include alcohols (e.g., methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, t-butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol), polyhydric alcohols (e.g. ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol) ), glycol derivatives (e.g. ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol diacetate, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, ethylene glycol monophenyl ether), amines (e.g. ethanolamine, diethanolamine, triethanolamine, N-methyl diethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenetriamine, triethylenetetramine, polyethyleneimine, tetramethylpropylenediamine), and other polar solvents (e.g., formamide, N,N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, sulfolane, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, acetonitrile, acetone) is included.
In this case, the water-soluble solvent may be used alone or in combination of two or more.

(Other additives)
The ink may contain other components other than the above components.
Other ingredients include, for example, anti-fading agents, emulsion stabilizers, penetration enhancers, ultraviolet absorbers, preservatives, antifungal agents, pH adjusters, surface tension adjusters, antifoaming agents, viscosity modifiers, and dispersion stabilizers. Known additives such as anti-rust agents, rust preventives, and chelating agents can be mentioned.

(Preferred physical properties of ink)
The viscosity of the ink is preferably 1.2 mPa·s or more and 15.0 mPa·s or less, more preferably 2 mPa·s or more and less than 13 mPa·s, and 2.5 mPa·s or more and less than 10 mPa·s. It is preferable.
The method for measuring viscosity is as described above.

The surface tension of the ink is preferably 25 mN/m or more and 40 mN/m or less, more preferably 27 mN/m or more and 37 mN/m or less.
The method for measuring surface tension is as described above.

The pH of the ink of the present disclosure at 25° C. is preferably from 6 to 11, more preferably from 7 to 10, and even more preferably from 7 to 9, from the viewpoint of dispersion stability.
The method for measuring pH is as described above.

[Image recording method]
The image recording method of the present disclosure includes:
Applying a pretreatment liquid of the present disclosure to form a layer (i.e., a layer derived from the pretreatment liquid) on an impermeable substrate;
a step of recording an image by applying ink containing a colorant and water to a part of the layer (i.e., the layer derived from the pretreatment liquid);
has.
The image recording method of the present disclosure may include other steps as necessary.

The image recording method of the present disclosure uses the pretreatment liquid of the present disclosure.
Therefore, according to the image recording method of the present disclosure, the same effects as the pretreatment liquid of the present disclosure can be achieved (that is, the generation of precipitates and the occurrence of blocking are suppressed).

<Process of applying pre-treatment liquid>
The step of applying the pretreatment liquid is a step of applying the pretreatment liquid to the surface of the non-permeable base material to form a layer.

The pretreatment liquid can be applied to the impermeable substrate by applying a known method such as a coating method, an inkjet method, or a dipping method.
As a coating method, a known coating method using a bar coater (for example, a wire bar coater), an extrusion die coater, an air doctor coater, a blade coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, a gravure coater, a flexo coater, etc. An example is a coating method.
The details of the inkjet method are the same as the inkjet method that can be applied to the step of applying ink described later.

The applied mass (g/m ² ) of the pretreatment liquid per unit area is not particularly limited as long as the components in the ink can be aggregated, but it is preferably 0.1 g/m ² to 10 g/m ² , or more. It is preferably 0.5 g/m ² to 6.0 g/m ² , more preferably 1.0 g/m ² to 4.0 g/m ² .

Further, in the step of applying the pretreatment liquid, the impermeable substrate may be heated before applying the pretreatment liquid.
The heating temperature may be set as appropriate depending on the type of non-permeable substrate or the composition of the pretreatment liquid, but it is preferable that the temperature of the non-permeable substrate is 20°C to 50°C, and 25°C to More preferably, the temperature is 40°C.

In the step of applying the pretreatment liquid, the layer may be formed by heating and drying the pretreatment liquid after applying the pretreatment liquid and before the step of applying ink described below.
Examples of means for heating and drying the pretreatment liquid include known heating means such as a heater, known blowing means such as a dryer, and means combining these.
Examples of methods for heating and drying the pretreatment liquid include:
A method of applying heat using a heater, etc. from the side opposite to the side to which the pretreatment liquid has been applied to the non-permeable substrate;
A method of applying warm air or hot air to the surface of a non-permeable substrate to which a pretreatment liquid has been applied;
A method of applying heat with an infrared heater from the side of a non-permeable substrate to which a pretreatment liquid has been applied or the side opposite to the side to which the pretreatment liquid has been applied;
A method that combines multiple of these,
etc.

The heating temperature during heat drying is preferably 35°C or higher, more preferably 40°C or higher.
Although there is no particular restriction on the upper limit of the heating temperature, examples of the upper limit include 100°C, preferably 90°C, and more preferably 70°C.
The heating drying time is not particularly limited, but is preferably from 0.5 seconds to 60 seconds, more preferably from 0.5 seconds to 20 seconds, and particularly preferably from 0.5 seconds to 10 seconds.

<Process of recording images>
The step of recording an image is a step of recording an image by applying ink containing a colorant and water to a part of the layer (that is, the layer derived from the pretreatment liquid).
This step allows ink to be selectively applied onto the non-permeable substrate, thereby allowing a desired image (specifically, a visible image) to be recorded.

In the step of applying ink, only one type of ink or two or more types of ink may be applied to a part of the layer derived from the pretreatment liquid. In the step of applying ink, when ink of two or more colors is applied, an image of two or more colors can be recorded.

As a method for applying ink in the step of applying ink, known methods such as a coating method, an inkjet method, and a dipping method can be applied.
Among these, the inkjet method is preferred.
There are no particular restrictions on the method of ejecting ink in the inkjet method, and there are known methods such as a charge control method that uses electrostatic attraction to eject ink, and a drop-on-demand method that uses the vibration pressure of a piezo element. The acoustic inkjet method uses radiation pressure to eject ink by converting an electrical signal into an acoustic beam and irradiating the ink with radiation pressure. Thermal inkjet method uses the pressure generated by heating the ink to form bubbles. Any method such as a bubble jet (registered trademark) method may be used.
In particular, the inkjet method is the method described in Japanese Patent Application Laid-open No. 54-59936, in which ink subjected to the action of thermal energy undergoes a rapid volume change, and the acting force due to this state change causes the ink to be ejected from a nozzle. The inkjet method can be effectively used.
As the inkjet method, the method described in paragraph numbers 0093 to 0105 of JP-A No. 2003-306623 can also be applied.

Application of ink by an inkjet method to the area of the non-permeable substrate to which the pretreatment liquid has been applied is performed by ejecting the ink from a nozzle of an inkjet head.
Inkjet head systems include the shuttle method, in which a short serial head performs printing while scanning in the width direction of the non-permeable substrate, and the shuttle method, in which recording elements are arranged to cover the entire side of the non-permeable substrate. There are two methods: a line method using a line head.
In the line method, an image can be recorded on the entire surface of a non-permeable base material by scanning the non-permeable base material in a direction intersecting the arrangement direction of recording elements. The line method eliminates the need for a conveyance system such as a carriage that scans the short head in the shuttle method. Furthermore, in the line method, compared to the shuttle method, complicated scanning control of the movement of the carriage and the non-permeable base material is not required, and only the non-permeable base material is moved. Therefore, according to the line method, image recording speed can be increased compared to the shuttle method.

The amount of ink droplets ejected from the nozzles of the inkjet head is preferably 1 pL (picoliter) to 10 pL, more preferably 1.5 pL to 6 pL, from the viewpoint of obtaining a high-definition image.
Furthermore, from the viewpoint of improving image unevenness and continuity of continuous gradations, it is also effective to eject a combination of different droplet amounts.

In the step of applying the ink, the applied ink may be dried by heating.
Examples of means for heating and drying include known heating means such as a heater, known blowing means such as a dryer, and means combining these.
Examples of methods for heating and drying ink include:
A method of applying heat using a heater etc. from the side opposite to the side on which the ink has been applied to the non-permeable base material;
A method of applying warm air or hot air to the ink-applied surface of a non-permeable substrate;
A method of applying heat using an infrared heater from the side opposite to the side to which the ink is applied or the pretreatment liquid is applied to the non-permeable base material,
A method that combines multiple of these,
etc.

The heating temperature during heat drying is preferably 55°C or higher, more preferably 60°C or higher, and particularly preferably 65°C or higher.
Although there is no particular restriction on the upper limit of the heating temperature, examples of the upper limit include 100°C, and 90°C is preferable.
There is no particular restriction on the time for heating and drying the ink, but it is preferably from 3 seconds to 60 seconds, more preferably from 5 seconds to 60 seconds, and particularly preferably from 10 seconds to 45 seconds.

In addition, in the step of applying the ink, the non-permeable substrate (specifically, the non-permeable substrate to which the pre-treatment liquid has been applied in the step of applying the pre-treatment liquid) is heated before applying the ink. You can.
The heating temperature may be set appropriately depending on the type of non-permeable base material and/or the composition of the ink, but it is preferable that the temperature of the non-permeable base material is 20°C to 50°C, and 25°C to More preferably, the temperature is 40°C.
In addition, in the step of applying the pretreatment liquid, when heating and drying the pretreatment liquid, even if the heating for heating and drying the pretreatment liquid also serves as heating of the non-permeable substrate before applying the ink. good.

The image recording method of the present disclosure may include other steps as necessary.
Other steps include forming an overcoat layer that covers the area to which the pretreatment liquid has been applied and the image recorded on a part of this area, and forming an image on the non-permeable substrate on which the image has been recorded. A step of laminating a laminate base material on the side where the laminate is applied can be mentioned.

[Example of image recording device]
An example of an image recording device that can be suitably used in the image recording method of the present disclosure will be described below with reference to FIG. 1.

FIG. 1 is a diagram conceptually showing an example of an image recording device.
As shown in FIG. 1, the image recording apparatus according to this example unwinds a long impermeable base material S1 wound into a roll using an unwinding device W1, and unwinds the unwound non-permeable base material S1 into a roll. The permeable substrate S1 is conveyed in the direction of the block arrow, passed through the pretreatment liquid applying device A1, the pretreatment liquid drying zone Dry1, the inkjet ink applying device IJ1, and the ink drying zone Dry2 in this order, and finally passed through the winding device. This is a device that winds up at W2.
In addition, since FIG. 1 is a conceptual diagram, the conveyance route of the non-permeable base material S1 is simplified and illustrated as if the non-permeable base material S1 is conveyed in one direction. In reality, it goes without saying that the transport path of the impermeable base material S1 may be meandering. As the transportation method for the impermeable base material S1, various web transportation methods such as a cylinder, a roller, etc. can be selected as appropriate.

In the pretreatment liquid application device A1 and the pretreatment liquid drying zone Dry1, the step of applying the pretreatment liquid in the image recording method according to the example described above is performed. The pretreatment liquid drying zone Dry1 may be omitted.
As for the method and conditions for applying the pretreatment liquid in the pretreatment liquid application device A1, the methods and conditions exemplified in the section of "Image recording method" can be applied.
As for the drying method and conditions in the pre-treatment liquid drying zone Dry1, the methods and conditions exemplified in the explanation of the "Image recording method" section can also be applied.
Further, on the upstream side in the conveyance direction of the impermeable substrate S1 with respect to the pretreatment liquid application device A1, a surface treatment section (not shown) for performing surface treatment (preferably corona treatment) on the impermeable substrate S1 is provided. ) may be provided.

The ink applying device IJ1 and the ink drying zone Dry2 perform the step of applying the ink described above. The ink drying zone Dry2 may be omitted.
Regarding the method and conditions for applying ink in the ink applying device IJ1, the methods and conditions exemplified in the section of the step of applying ink can be applied.
As for the drying method and conditions in the ink drying zone Dry2, the methods and conditions exemplified in the section of the step of applying ink can be applied.

Although not shown, the structure of the ink applying device IJ1 may include at least one inkjet head.
The inkjet head may be a shuttle head, but from the viewpoint of speeding up image recording, a line head in which a large number of ejection ports (nozzles) are arranged across the width of a long non-permeable base material is preferred.
From the viewpoint of speeding up image recording, the structure of the ink applying device IJ1 preferably includes a line head for black (K) ink, a line head for cyan (C) ink, a line head for magenta (M) ink, and a line head for yellow (Y) ink.
More preferably, the structure of the ink applying device IJ1 includes at least two of the above four line heads, and these two or more line heads are arranged in a direction in which the non-permeable substrate is conveyed (in the direction of the block arrow). It is an arrayed structure.
The ink applying device IJ1 further includes a line head for white ink, a line head for orange ink, a line head for green ink, a line head for purple ink, a line head for light cyan ink, and a line for light magenta ink. At least one of the heads may include a line head.

As described above, in the image recording apparatus according to this example, the elongated non-permeable base material S1 wound into a roll is unwound by the unwinding device W1, and the unwound non-permeable base material S1 is conveyed in the direction of the block arrow, the pretreatment liquid is applied and dried by the pretreatment liquid applying device A1 and the pretreatment liquid drying zone Dry1, and then the ink is applied by the inkjet ink applying device IJ1 and the ink drying zone Dry2. By performing drying and drying, an image can be recorded. The impermeable substrate S1 on which the image is recorded (ie, the image recording material) is wound up by the unwinding device W2.

[Image records]
The image recording material of the present disclosure is
a non-permeable substrate;
A layer disposed on an impermeable substrate and formed with the pretreatment liquid of the present disclosure (a layer that is a dried product of the pretreatment liquid);
an image containing a colorant disposed on a portion of this layer;
Equipped with

Since the image recording material of the present disclosure includes a layer formed by the pretreatment liquid of the present disclosure (a layer that is a dried product of the pretreatment liquid), the same effects as the pretreatment liquid of the present disclosure can be achieved (i.e., , the generation of precipitates and the occurrence of blocking are suppressed).

The image recording material of the present disclosure is suitably manufactured by the above-described image recording method of the present disclosure.
Specifically, the layer disposed on the impermeable substrate is formed by applying the pretreatment liquid of the present disclosure onto the impermeable substrate.
In the image recording material, the interface between the image (ie, the image derived from the ink) and the layer (ie, the layer derived from the pretreatment liquid) does not necessarily have to be clear. For example, there may be a region between the image and the layer where ink components, pretreatment liquid components, and ink components are mixed.

The image recording material may include layers and other elements other than images, if necessary.
Other elements include an overcoat layer disposed over the layers and images, a laminate substrate laminated over the layers and images, and the like.

[Method for manufacturing recording medium]
The method for manufacturing a recording medium of the present disclosure includes a step of applying the pretreatment liquid of the present disclosure to form a layer on an impermeable substrate.
The method for manufacturing a recording medium of the present disclosure may include other steps as necessary.

In the method for manufacturing a recording medium of the present disclosure, the pretreatment liquid of the present disclosure is used.
Therefore, according to the method for manufacturing a recording medium of the present disclosure, the same effects as the pretreatment liquid of the present disclosure can be achieved (that is, the generation of precipitates and the occurrence of blocking are suppressed).

A preferred embodiment of the step of applying a pretreatment liquid in the method for manufacturing a recording medium of the present disclosure is the same as a preferred embodiment of the step of applying a pretreatment liquid in the image recording method of the present disclosure.
A preferred embodiment of the method for manufacturing a recording medium of the present disclosure is a mode in which the step of recording an image is omitted from the image recording method of the present disclosure (for example, in the image recording method of the present disclosure, the step of producing an image is omitted). aspect).

The method of manufacturing a recording medium of the present disclosure can be carried out using, for example, the image recording apparatus according to the example described above (see FIG. 1).
In this case, for example, a long impermeable base material S1 wound into a roll is unwound by an unwinding device W1, and the unwound impermeable base material S1 is conveyed in the direction of the block arrow. Then, the pretreatment liquid is applied and dried by the pretreatment liquid application device A1 and the pretreatment liquid drying zone Dry1, and then the pretreatment is performed without applying and drying the ink by the inkjet ink application device IJ1 and the ink drying zone Dry2. The impermeable base material S1 (ie, the recording medium) to which the liquid has been applied and dried is wound up by the unwinding device W2.

Further, the method for manufacturing a recording medium of the present disclosure includes manufacturing a recording medium having a structure in which the inkjet ink applying device IJ1 and the ink drying zone Dry2 in the structure of the image recording apparatus according to the example described above (see FIG. 1) are omitted. It can also be carried out using a device.

[Recording medium]
The recording medium of the present disclosure is
a non-permeable substrate;
A layer disposed on an impermeable substrate and formed with the pretreatment liquid of the present disclosure (a layer that is a dried product of the pretreatment liquid);
Equipped with

Since the image recording material of the present disclosure includes a layer formed by the pretreatment liquid of the present disclosure (a layer that is a dried product of the pretreatment liquid), the same effects as the pretreatment liquid of the present disclosure can be achieved (i.e., , the generation of precipitates and the occurrence of blocking are suppressed).
The recording medium of the present disclosure is suitably manufactured by the method for manufacturing a recording medium of the present disclosure described above.

Preferred embodiments of the layers in the recording medium of the present disclosure are the same as preferred embodiments of the layers in the image recording material of the present disclosure.
A preferred embodiment of the recording medium of the present disclosure is an embodiment in which the image is omitted from the image recording material of the present disclosure.
The image recording material of the present disclosure can be manufactured by applying the above-described ink to a portion of the layer of the recording medium of the present disclosure to record an image.

Examples of the present disclosure will be shown below, but the present disclosure is not limited to the following examples.
In the following, unless otherwise specified, "parts" and "%" are based on mass.
Moreover, in the following, "water" means ion-exchanged water unless otherwise specified.

[Example 1]
<Preparation of pretreatment liquid>
A pretreatment liquid having the following composition was prepared.

-Composition of pre-treatment liquid-
・Adipic acid (polycarboxylic acid)
...1.0% by mass
・Glutaric acid (polycarboxylic acid)
...5.0% by mass
・Succinic acid (polycarboxylic acid)
...2.0% by mass
・Olfine E1010 (surfactant) (acetylene glycol surfactant manufactured by Nissin Chemical Industry Co., Ltd.)
...0.5% by mass
- Pesresin A615GE (resin) (aqueous dispersion of composite particles of polyester resin and acrylic resin (volume average particle diameter 40 nm) manufactured by Takamatsu Yushi Co., Ltd.)
... 10.0% by mass as the amount of resin particles
・Water…Remaining amount totaling 100% by mass

<Preparation of cyan ink>
A cyan ink having the following composition was prepared.

-Composition of cyan ink-
・Projet Cyan APD1000 (manufactured by FUJIFILM Imaging Colorants, cyan pigment dispersion, pigment concentration: 12% by mass)
...2.4% by mass as solid content
・1,2-Propanediol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (water-soluble solvent)
...20% by mass
・Olfine E1010 (manufactured by Nissin Chemical Industry Co., Ltd.) (surfactant)
...1% by mass
・The following acrylic resin particles IA-1 (resin particles)
...8% by mass as the amount of resin particles
・Snowtex (registered trademark) XS (manufactured by Nissan Chemical Co., Ltd., colloidal silica)
...0.06% by mass as solid content of silica
・Water…Remaining amount totaling 100% by mass

(Preparation of aqueous dispersion of acrylic resin particles IA-1)
Acrylic resin particles IA-1 in the composition of the above cyan ink were produced as follows.
560.0 g of methyl ethyl ketone was charged into a 2 liter three-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction tube, and the temperature was raised to 87°C. Next, while maintaining the reflux state in the reaction vessel (hereinafter, the reflux state was maintained until the end of the reaction), 220.4 g of methyl methacrylate, 301.6 g of isobornyl methacrylate, and 58.0 g of methacrylic acid were added to the methyl ethyl ketone in the reaction vessel. , 108 g of methyl ethyl ketone, and 2.32 g of "V-601" (polymerization initiator; dimethyl 2,2'-azobis(2-methylpropionate), manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.). The solution was added at a uniform rate so that the addition was completed within an hour. After the dropwise addition was completed, the solution was stirred for 1 hour, and then the following step (1) was performed on the solution after stirring for 1 hour.
Step (1)...A solution consisting of 1.16 g of "V-601" and 6.4 g of methyl ethyl ketone was added and stirred for 2 hours.

Subsequently, the operation of step (1) above was repeated four times, and then a solution consisting of 1.16 g of "V-601" and 6.4 g of methyl ethyl ketone was added and stirring was continued for 3 hours. (referred to as “reaction”).
After the reaction, the temperature of the solution was lowered to 65°C, 163.0 g of isopropanol was added, and the mixture was allowed to cool to form a mixture of methyl methacrylate/isobornyl methacrylate/methacrylic acid (=38/52/10 [mass ratio]). A polymerization solution containing a polymer (solid content concentration 41.0%) was obtained.
The copolymer had a weight average molecular weight (Mw) of 63,000 and an acid value of 65.1 (mgKOH/g).

Next, 317.3 g of the obtained polymerization solution (solid content concentration 41.0% by mass) was weighed, and 46.4 g of isopropanol and 1.65 g of a 20% aqueous maleic anhydride solution (water-soluble acidic compound, copolymer (equivalent to 0.3% by mass as maleic acid based on the combined mass) and 40.77 g of a 2 mol/L NaOH aqueous solution were added, and the temperature of the liquid in the reaction vessel was raised to 70°C.
Next, 380 g of distilled water was added dropwise to the solution heated to 70° C. at a rate of 10 ml/min to perform water dispersion (dispersion step).
Thereafter, a total of 287.0 g of isopropanol, methyl ethyl ketone, and distilled water were distilled off by maintaining the temperature of the liquid in the reaction vessel at 70° C. for 1.5 hours under reduced pressure (solvent removal step). To the obtained liquid, 0.278 g (440 ppm as benzisothiazolin-3-one based on the polymer solid content) of Proxel GXL (S) (manufactured by Arch Chemicals Japan) was added.
The obtained liquid was filtered through a 1 μm filter and the filtrate was collected to obtain an aqueous dispersion of acrylic resin particles IA-1 with a solid content concentration of 26.5% by mass.
The glass transition temperature (Tg) of the acrylic resin particles IA-1 was 120° C., and the volume average particle diameter was 10 nm.
In this example, this aqueous dispersion of acrylic resin particles IA-1 was used, and 8% by mass of acrylic resin particles IA-1 was contained in the cyan ink.

<Evaluation>
The following evaluations were performed using the pretreatment liquid and ink described above.
The results are shown in Table 1.

(precipitate)
FE2001 (polyethylene terephthalate (PET) base material, manufactured by Futamura Chemical Co., Ltd., thickness 25 μm, width 500 mm, length 2000 m) as an impermeable base material was transported at 500 mm/sec, and the pretreatment liquid was transferred to a wire bar coater. The coating was applied at a coating weight of 1.7 g/m ² (liquid coating amount). The impervious substrate coated with the pretreatment liquid was placed on a hot plate at 80°C, and the pretreatment liquid was dried for 30 seconds to form a layer derived from the pretreatment liquid. A non-permeable base material with a layer derived from the pretreatment liquid was wound up into a roll shape so that the surface pressure was 50 kPa to obtain a roll 1. The obtained roll 1 was left at room temperature (25° C.) for one day.
The length of the non-permeable base material with a layer derived from the pre-treatment liquid is approximately 1000 m after unwinding the roll 1. The length of the non-permeable base material in the longitudinal direction is 29.7 cm, Ten A4 size samples each having a length of 21 cm in the width direction of the permeable base material were cut out.
The layer derived from the pretreatment liquid in the 10 cut out sheets was visually observed to confirm the presence or absence of precipitates. Based on the confirmed results, the precipitates were evaluated according to the following evaluation criteria.
In addition, it was determined that a precipitate was generated when the following 1 or 2 was satisfied.
1. 2. When contaminants with a diameter of 1 mm or more are present in the layer derived from the pretreatment liquid. When there is a part in the layer derived from the pretreatment liquid that has a higher haze value than other parts In the evaluation criteria below, the rank where the generation of precipitates is most suppressed is A.

-Evaluation criteria for precipitates-
A: No precipitates were visually recognized in all samples (10 samples).
B: Precipitates were visually recognized in one of the 10 samples, but no precipitates were visually recognized in the remaining samples.
C: Precipitates were visible on 2 to 4 of the 10 samples, but no precipitates were visible on the remaining samples.
D: Precipitates were visually observed in 5 to 10 of the 10 samples.

(blocking)
The same operation as in the evaluation of precipitates was performed until Roll 1 was left at room temperature for one day.
The length of the non-permeable base material with a layer derived from the pre-treatment liquid is approximately 1000 m after unwinding the roll 1. The length of the non-permeable base material in the longitudinal direction is 29.7 cm, Ten A4 size samples each having a length of 21 cm in the width direction of the permeable base material were cut out.
The layers derived from the pretreatment liquid in the 10 cut out sheets were visually observed to confirm the presence or absence of transfer marks (that is, transfer traces on the back surface of the PET substrate with respect to the surface of the layer derived from the pretreatment liquid). Based on the confirmed results, blocking was evaluated using the following evaluation criteria.
In the following evaluation criteria, A is the rank in which the occurrence of blocking is most suppressed.

-Blocking evaluation criteria-
A: No transfer marks were visible in all samples (10 sheets).
B: Transfer marks were visible on 1 to 2 of the 10 samples, but were not visible after transfer on the remaining samples.
C: Transfer marks were visible on 3 to 10 of the 10 samples.

(bleed)
FE2001 (PET base material, manufactured by Futamura Chemical Co., Ltd., thickness 25 μm, width 500 mm, length 2000 m) as a non-permeable base material was conveyed at 500 mm/sec, and 1.7 g of pretreatment liquid was applied using a wire bar coater. /m ² (liquid coating amount), and immediately after coating, it was dried at 50° C. for 2 seconds to obtain a layer derived from the pretreatment liquid. A character image was recorded on the layer derived from the obtained pretreatment liquid by an inkjet method using the cyan ink described above under the following image recording conditions. The character images shown in Figure 2 (unicode: U+9DF9) are 2pt, 3pt, 4p.
It was recorded at t and 5pt, respectively. Here, pt means DTP point indicating font size, and 1 pt is 1/72 inch.
The obtained character images were observed and the blurring of the images was evaluated according to the following evaluation criteria.
In the following evaluation criteria, A is the rank in which blurring of the image is most suppressed.

-Image recording conditions-
- Inkjet head: A 1,200 dpi (dot per inch, 1 inch is 2.54 cm)/20 inch width piezo full line head was used.
- Amount of ejected droplets: 2.4 pL each.
- Driving frequency: 30 kHz (base material conveyance speed 635 mm/sec).

-Evaluation criteria for image blur-
A: 2pt characters were reproducible.
B: 3pt characters could be reproduced, but 2pt characters could not be reproduced.
C: 4pt characters could be reproduced, but characters of 3pt or less could not be reproduced.
D: 4pt characters could not be reproduced.
Here, "reproducible" means that when viewed from a distance of 0.5 m, in the character image shown in Fig. 2, the horizontal line indicated by 1 shown in Fig. 3 and the 2 This means that the horizontal line represented by is separated.

[Examples 2 to 23, Comparative Examples 1 to 9]
The same operation as in Example 1 was performed except that the composition of the pretreatment liquid was changed as shown in Tables 1 and 2.
The results are shown in Tables 1 and 2.

In Tables 1 and 2, the numerical value in the column for each component means the mass % with respect to the total amount of the pretreatment liquid, and a blank column means that the component is not contained.
The numerical value in the "Resin" column means the amount of resin (solid content), not the amount of the aqueous resin dispersion.

Details of the resins in Tables 1 and 2 are as follows.
・SF300
...Superflex 300 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., an aqueous dispersion of polyurethane resin particles (volume average particle diameter 15 nm)).
・Acrylic LxA-1
...Aqueous dispersion of acrylic resin particles prepared as follows.
・PEG6000
... Polyethylene glycol 6000 (a water-soluble nonionic resin) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

<Preparation of acrylic LxA-1 (aqueous dispersion of acrylic resin particles)>
In the preparation of the pretreatment liquid in Example 5, by using acrylic LxA-1 (aqueous dispersion of acrylic resin particles), the pretreatment liquid contained 10.0% by mass of acrylic resin particles as the amount of resin particles. I let it happen.
Acrylic LxA-1 (aqueous dispersion of acrylic resin particles) was prepared as follows.
3.0 g of sodium dodecylbenzenesulfonate (62% by mass aqueous solution, manufactured by Tokyo Chemical Industry Co., Ltd.) and 376 g of water were added to a 1000 ml three-necked flask equipped with a stirrer and a cooling tube, and the mixture was heated to 90° C. under a nitrogen atmosphere. In a heated three-necked flask, a mixed solution containing 11.0 g of a 50% by mass aqueous solution of sodium 2-acrylamido-2-methylpropanesulfonate (manufactured by Aldrich) in 20 g of water and 2-hydroxy methacrylate were added. Ethyl (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 12.5 g, 2-(2-ethoxyethoxy)ethyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) 5.0 g, benzyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) 17.0 g, and 10.0 g of styrene (St; manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) were mixed together, and solution C was prepared by dissolving 6.0 g of sodium persulfate (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) in 40 g of water. They were dripped at the same time over time. After the dropwise addition, the reaction was further carried out for 3 hours to obtain 500 g of acrylic LxA-1 (aqueous dispersion of acrylic resin particles) (solid content (ie, amount of acrylic resin particles): 10.1% by mass).
The glass transition temperature of the acrylic resin particles in Acrylic LxA-1 was 26°C, and the weight average molecular weight of the acrylic resin particles was 69,000.

"PG" in the water-soluble solvent column in Tables 1 and 2 is propylene glycol.

As shown in Tables 1 and 2, the pretreatment liquid for non-permeable substrates contains water and three or more types of carboxylic acids, and the content of the carboxylic acid whose ClogP is less than -1.00. In Examples 1 to 23 in which the pretreatment liquid was used in an amount of 2.0% by mass or less based on the total amount of the pretreatment liquid, the generation of precipitates and blocking were suppressed.

In contrast to the examples, the results of the comparative examples were as follows.
In Comparative Examples 1 to 5 in which the number of types of carboxylic acids contained was two or less, the generation of precipitates could not be suppressed.
Furthermore, in Comparative Examples 6 to 9, in which the content of carboxylic acid with a ClogP of less than −1.00 was more than 2.0% by mass based on the total amount of the pretreatment liquid, the occurrence of blocking could not be suppressed.

From the results of Examples 11 and 22, when the total content of three or more types of carboxylic acids is 5.0% by mass or more based on the total amount of the pretreatment liquid (Example 11), image bleeding is more suppressed. I know it will happen.
From the results of Examples 20 and 22, when the total content of three or more types of carboxylic acids is 13.0% by mass or less based on the total amount of the pretreatment liquid (Example 20), image blocking is more suppressed. I know it will happen.

From the results of Examples 1 to 19, three or more carboxylic acids
a polycarboxylic acid A1 having a ClogP of -1.00 or more and less than -0.50;
Polyvalent carboxylic acid A2, which is a polyvalent carboxylic acid whose ClogP is -0.50 or more and -0.10 or less,
Polyvalent carboxylic acid A3, which is a polyvalent carboxylic acid whose ClogP is more than −0.10 and less than or equal to 0.50;
(Examples 1 to 7, 11, 12, 13, and 19), it can be seen that the generation of precipitates is further suppressed.

From the results of Examples 1 to 6, in Examples 1 to 5 where the pretreatment liquid contains a resin and the resin contains resin particles, the pretreatment liquid contains a resin and the resin does not contain resin particles. It can be seen that blocking and bleeding are more suppressed compared to Example 6 containing a water-soluble resin (PEG6000).

S1 Impermeable base material W1 Unwinding device A1 Pretreatment liquid applying device Dry1 Pretreatment liquid drying zone IJ1 Ink applying device Dry2 Ink drying zone W2 Winding device 11, 12 Horizontal line

Claims (13)

A pretreatment liquid for non-permeable substrates containing water and three or more types of carboxylic acids,
The content of the carboxylic acid having a ClogP of less than −1.00 is 2.0% by mass or less based on the total amount of the non-permeable substrate pretreatment liquid,
A pretreatment liquid for non-permeable substrates, wherein the total content of the three or more carboxylic acids is 5.0% by mass to 13.0% by mass with respect to the total amount of the pretreatment liquid for non-permeable substrates. . The pretreatment liquid for non-permeable substrates according to claim 1, wherein the weight average ClogP of the three or more types of carboxylic acids is 0.50 or less. The pretreatment liquid for non-permeable substrates according to claim 1 or 2, wherein the weight average ClogP of the three or more types of carboxylic acids is -1.00 or more. The pretreatment liquid for a non-permeable substrate according to any one of claims 1 to 3 , wherein the three or more carboxylic acids include two or more polyhydric carboxylic acids. The three or more carboxylic acids are
a polycarboxylic acid A1 having a ClogP of -1.00 or more and less than -0.50;
Polyvalent carboxylic acid A2, which is a polyvalent carboxylic acid whose ClogP is -0.50 or more and -0.10 or less,
Polyvalent carboxylic acid A3, which is a polyvalent carboxylic acid whose ClogP is more than −0.10 and less than or equal to 0.50;
The pretreatment liquid for non-permeable substrates according to any one of claims 1 to 4 , comprising: The content mass of polyvalent carboxylic acid A1, which is a polyvalent carboxylic acid whose ClogP is -1.00 or more and less than -0.50, is [A1],
The content mass of polyvalent carboxylic acid A2, which is a polyvalent carboxylic acid whose ClogP is -0.50 or more and -0.10 or less, is [A2],
When the content mass of polyvalent carboxylic acid A3, which is a polyvalent carboxylic acid whose ClogP is more than -0.10 and 0.50 or less, is [A3],
The pretreatment liquid for non-permeable substrates according to any one of claims 1 to 5 , wherein the [A2]/([A1]+[A3]) ratio is 0.5 to 5.0. The pretreatment liquid for non-permeable substrates according to any one of claims 1 to 6 , further comprising a resin. The pretreatment liquid for non-permeable substrates according to claim 7 , wherein the resin contains resin particles. The pretreatment liquid for non-permeable substrates according to any one of claims 1 to 8 ,
an ink containing water and a colorant;
An ink set with. A step of applying the pretreatment liquid for impermeable substrates according to any one of claims 1 to 8 on the impermeable substrate to form a layer;
a step of recording an image by applying ink containing a colorant and water to a part of the layer;
An image recording method comprising: a non-permeable substrate;
A layer disposed on the non-permeable base material and formed from the pre-treatment liquid for a non-permeable base material according to any one of claims 1 to 8 ;
an image containing a colorant disposed on a portion of the layer;
An image recording material comprising: A method for producing a recording medium, comprising the step of applying the pretreatment liquid for impermeable substrates according to any one of claims 1 to 8 on an impermeable substrate to form a layer. a non-permeable substrate;
A layer disposed on the non-permeable base material and formed from the pre-treatment liquid for a non-permeable base material according to any one of claims 1 to 8 ;
A recording medium comprising: