JP7340121B1 - Varnish composition for gravure printing ink - Google Patents

Abstract

[Problem] To provide an environmentally friendly polyurethane varnish composition that can be used in the formulation of general gravure printing inks and can adapt to changes in base materials. [Solution] A varnish composition for gravure printing ink containing an acetate ester solvent and a polyurea urethane resin and used in combination with a resin other than the resin, wherein the proportion of the acetate ester solvent in the composition is 60% or more. , a varnish composition for gravure printing ink in which the polyurea urethane resin has a structure defined in a) to e). a) The polymer chain has a hydroxyl group represented by formula (1) or (2) b) A part of the hydroxyl group is silylated, so that the amount of hydroxyl group is 45 to 45% in terms of the hydroxyl value of the resin itself. adjusted to 80 mgKOH/g; c) has isocyanate-derived urea bonds in a molar ratio of urethane bonds/urea bonds = 10/1 to 10/3; and d) has a biomass component resulting from a dimer acid-derived structure in a mass ratio. Contains 30% or more and e) 9% or more of the weight of the resin is a structure derived from the raw material carbon dioxide [Selection diagram] None

Description

The present invention relates to a polyurethane resin-based varnish composition (resin-containing composition) which is an ink varnish suitable for producing gravure printing inks. More specifically, the polyurethane resin-based varnish composition of the present invention has excellent compatibility with other resins used for the purpose of imparting useful functions during the production of gravure printing inks, and thus is similar to conventional ink varnishes. can be used in combination with these resins, and when used in the production of gravure printing ink, it is possible to provide a printed image (ink film) that has excellent curability, adheres to the substrate and has excellent adhesiveness, and in addition, The present invention relates to a technology for providing a varnish composition for gravure printing ink which is excellent in environmental friendliness and which enables the use of a new type of polyureaurethane resin using carbon dioxide as a raw material.

Polyurethane resin is a general term for polymers obtained by a polyaddition reaction using raw materials such as a diisocyanate compound, a polyol compound, and a chain extender such as a low-molecular-weight diol. It has a wide variety of variations depending on the combination of these raw materials, and is most commonly used as a binder for gravure printing inks. Polyurethane resins for ink binders are designed to have terminal functional groups and polar groups in the polymer chain, so that they adhere well to many substrates and have excellent film physical properties. Inks using urethane resins are characterized by excellent adhesiveness, laminating strength, hot water resistance such as boiling treatment, and less residual solvent in printed matter.

In the development of printing inks in recent years, many manufacturers are actively working on environmental issues, and there is a movement to construct products using materials that are excellent in environmental conservation. In particular, biological resources (biomass) other than fossil resources are attracting attention as non-exhaustible industrial resources. Plants grow by absorbing _CO2 from the atmosphere through photosynthesis that uses sunlight as energy. The amount of _CO2 absorbed by photosynthesis and the amount of _CO2 emitted by incineration of plants are offset, and it is thought that it does not affect the increase or decrease of _CO2 in the atmosphere (carbon neutral), and its development is expected. Among products that use plant-derived raw materials, biomass-mark certified products are safe, contribute to the formation of a recycling-oriented society, and help prevent global warming. From this point of view, many inventions have been made regarding the use of polyurethane resins using raw materials with a high degree of biomass as binders for printing inks.

These biomass-based polyurethane resins have begun to be used as substitutes for conventional products by replacing the same chemical structure as conventionally used polyurethane resins derived from fossil raw materials with biomass materials. For example, in the technique described in Patent Document 1, the polyester polyol used in the synthesis of the polyurethane resin is replaced with a biomass-derived component for production. However, the types of such biomass-derived materials are limited, and the degree of freedom in resin structural design is low, making it difficult to impart new performance. For example, the technology described in Patent Document 2 uses a biomass-derived dimer acid or the like, and the technology described in Patent Document 3 uses plant-derived 1,2-propadiol, but both are conventional. It remains to have almost the same performance as the polyurethane resin derived from fossil raw materials.

While biomass conversion is required for polyurethane resin, in recent years, from the viewpoint of recycling, eco-friendliness of packaging bodies is also progressing. For example, the composition of substrates is changing, such as the use of transparent silica deposition films and alumina oxide deposition films instead of aluminum foil, and the performance required of printing inks is diversifying. Therefore, it is necessary to use other polymers in addition to the performance of polyurethane resin alone. For the purpose of providing a suitable laminating ink composition for flexible packaging, it has been proposed to use a polyurethane resin and a vinyl chloride-vinyl acetate copolymer together as a binder resin.

Under these circumstances, there is a demand for environmentally friendly polyurethane resins that are different from conventional biomass-based polyurethane resins. In recent years, as a new environmentally friendly polyurethane resin, the development of a polyurethane resin that directly uses carbon dioxide has been reported based on the concept of carbon recycling rather than the carbon-neutral nature of biomass materials. Specifically, it is a polyurethane-based resin obtained by an addition reaction of a cyclic carbonate compound obtained by reacting an epoxy compound with carbon dioxide and an amine compound. Unlike petroleum-derived polyurethane resins, this polyurethane resin using carbon dioxide as a raw material has a chemical structure with hydroxyl groups in side chains, and therefore has properties different from those of conventional polyurethane resins. For example, the technique described in Patent Document 5, which aims to provide a film having an excellent gas barrier function, is used to form a layer having gas barrier properties. Further, in the technique described in Patent Document 6, the adhesion to metals, other resins, etc. is particularly good, and the content of the carbon dioxide-derived structural part is maintained relatively high, while the polyhydroxyl has excellent flexibility. We have proposed urethane resin and are also developing it as an adhesive. The technique described in Patent Document 7 is developed with the aim of providing a printing ink binder used for printing ink such as gravure printing ink. If a polyhydroxyurethane resin can be used as a binder for printing ink in a favorable state, it can be expected to improve the adhesiveness of the formed ink film layer to a deposited film or the like.

Japanese Patent Application Laid-Open No. 2021-130826 Japanese Patent No. 6458089 Japanese Patent No. 6637205 Japanese Patent No. 4882206 Japanese Patent No. 5604329 Japanese Patent No. 6341888 Japanese Patent No. 5087063

However, according to the studies of the present inventors, the technique proposed in Patent Document 4, in which a polyurethane resin and a vinyl chloride-vinyl acetate copolymer are used together when used as a binder resin, is applied to a polyhydroxyurethane resin. When applied, there is a problem of poor compatibility with the vinyl chloride-vinyl acetate copolymer. In addition, it has poor solubility in non-polar solvents such as ethyl acetate used in printing inks, and requires the addition of alcohol. There was also the problem of

In order to solve the above problems, the present inventors have improved the polyurethane-based polymer (polyhydroxyurethane resin) synthesized using carbon dioxide as a raw material to improve the solubility in non-polar solvents such as ethyl acetate. and compatibility with other resins such as vinyl chloride-vinyl acetate copolymer (hereinafter sometimes referred to as vinyl chloride acetate resin) that is blended in printing inks in recent years. We recognized that it could be expected to be put to practical use as a binder for environmentally friendly gravure printing ink.

Therefore, the object of the present invention is to provide a new type of polyurethane-based environmentally friendly type that can be used in good condition without problems in the formulation of general gravure printing inks, and can respond to recent changes in substrates. is to provide a varnish composition of In particular, the object of the present invention is to make it possible to apply a recently developed new polyurethane resin that can contribute to the reduction of greenhouse gases to a varnish composition for gravure printing ink by using carbon dioxide as a raw material. In this way, we have improved the solubility in ester-based solvents such as ethyl acetate, which was a drawback of the conventional technology, and improved the compatibility with other resins, which are useful ingredients for printing inks. It is to be. In addition to these improvements, the object of the present invention is to retain the advantages of having hydroxyl groups in the structure of a new type of polyurethane resin, such as good adhesion to substrates and excellent laminate strength. Another object of the present invention is to provide a resin composition useful for ink varnish. A specific object of the present invention is to control the amount of hydroxyl groups in the structure of a new type of polyurethane resin, thereby providing an environment-friendly resin that can be suitably used for the preparation of gravure printing ink that solves the above-mentioned problems. It is to develop technology with high practical value.

［式（１）～（４）中のＰはいずれもポリマー鎖との結合部を示しており、式（３）又は（４）中のＲは、それぞれ独立に水素又はメチル基を示す。］ The above objects are achieved by the present invention described below. That is, the present invention provides the following varnish composition for gravure printing ink.
[1] A varnish composition for gravure printing ink that contains an acetic acid ester-based organic solvent and a polyureaurethane resin as constituent elements, and is used in combination with a resin other than the polyureaurethane resin,
Gravure, characterized in that the ratio of the acetic acid ester-based organic solvent in the composition is 60% by mass or more, and the polyureaurethane resin has all of the structures defined in the following a) to e). A varnish composition for printing inks.
a) having a hydroxyl group of any structure represented by the following formula (1) or (2) in the polymer chain,
b) Some of the hydroxyl groups have a silylated structure represented by the following formula (3) or (4), so that the hydroxyl content is converted to the hydroxyl value of the polyureaurethane resin alone. is adjusted within the range of 45 mgKOH / g to 80 mgKOH / g,
c) having a urea bond in addition to the urethane bond, the urea bond is a structure derived from an aliphatic isocyanate, and the molar ratio of the urea bond in the resin is urethane bond/urea bond=10/1 to 10/ 3 and
d) containing 30% or more by mass of a biomass component resulting from a chemical structure derived from dimer acid,
e) 9% by mass or more of the weight of the resin consists of structures derived from the carbon dioxide of the raw material

[P in formulas (1) to (4) all represent a bond with a polymer chain, and R in formula (3) or (4) each independently represents hydrogen or a methyl group. ]

Preferred embodiments of the varnish composition for gravure printing inks described above include the following configurations.
[2] The polyureaurethane resin is made from one or more compounds represented by the following formula (5) or (6) as a raw material, and has a chemical structure derived from the raw material in the polymer chain. A varnish composition for gravure printing ink according to the above [1].

[3] The urea bond is derived from any one or more isocyanate compounds in the group consisting of isophorone diisocyanate, 1,6-hexamethylene diisocyanate and hydrogenated xylylene diisocyanate, and solution viscosity at 25°C is 500 mPa·s to 5000 mPa·s, the varnish composition for gravure printing ink according to the above [1] or [2].
[4] Any one of the above [1] to [3], wherein the urea bond further comprises a urea bond derived from an isocyanurate-type, biuret-type, or adduct-type trifunctional or higher aliphatic polyisocyanate compound. A varnish composition for gravure printing inks.

[5] The varnish composition for gravure printing ink according to any one of the above [1] to [4], wherein the proportion of the acetic acid ester-based organic solvent is 90% by mass or more.
[6] Any of the above [1] to [5], further comprising at least one of vinyl chloride-vinyl acetate copolymer or chlorinated polypropylene, or cellulose resin having an acetyl group, a propionyl group and a hydroxy group. 1. Varnish composition for gravure printing ink according to 1.

According to the present invention, a new type of polyurethane resin that can be used in good condition without problems in the formulation of general gravure printing ink and that can respond to recent changes in substrates is used as an essential component. A varnish composition for an environmentally friendly gravure printing ink is provided. According to the present invention, in particular, by using carbon dioxide as a raw material, by controlling the hydroxyl groups in the structure of a new type of polyurethane resin that contributes to the reduction of greenhouse gases, it can be applied as a varnish composition. improved solubility in ester solvents such as ethyl acetate, which was a drawback of the prior art, and improved compatibility with other useful resin components blended in printing inks. is realized. In addition, according to the present invention, an environmentally friendly polyurethane resin that retains the advantages obtained by having hydroxyl groups in the structure of a new type of polyurethane resin, such as good adhesion to substrates and excellent laminate strength. It becomes possible to provide a varnish composition for gravure printing ink with high practical value of the mold.

Next, the present invention will be described in more detail with preferred modes for carrying out the invention. Essential components in the varnish composition of the present invention are an acetic acid ester-based organic solvent and a specific polyureaurethane resin, and the varnish composition for gravure printing ink can be used in combination with resins other than the polyureaurethane resin. The varnish composition of the present invention may contain other organic solvents other than the acetic acid ester-based organic solvent used in the production of gravure printing inks, and if necessary, add appropriate additives to the above components. can also be added. For example, other organic solvents may include lower alcohols such as methyl ethyl ketone (MEK) and isopropyl alcohol (IPA). Hereinafter, the constituent components of the varnish composition for gravure printing ink of the present invention (hereinafter simply referred to as varnish composition) will be described.

[Polyurea urethane resin]
First, the polyureaurethane resin, which is an essential component characterizing the varnish composition of the present invention, will be described. A polyureaurethane resin is produced by a two-stage reaction of "first step" and "second step" described below. In the first step, a compound having at least one five-membered cyclic carbonate group in the molecule (hereinafter referred to as a five-membered cyclic carbonate compound or cyclic carbonate compound) and at least one amino group in one molecule As defined in a), a hydroxypolyurethane resin having hydroxyl groups of either structure represented by formula (1) or (2) in the polymer chain is produced by a polyaddition reaction with a compound having . In the first step, a polyaddition reaction is performed by adjusting the molar ratio of the cyclic carbonate compound and the compound having an amino group so that the molecular end of the polyurethane resin having a hydroxyl group produced in this step becomes an amino group. I do. Next, in the second step, an isocyanate compound is added to the resin obtained in the previous first step, and a urea bond is introduced through an addition reaction between the amino group and the isocyanate group to increase the molecular weight. A polyureaurethane resin is prepared. In the polyureaurethane resin, which is an essential component constituting the varnish composition of the present invention, as defined in b), some of the hydroxyl groups of the hydroxypolyurethane resin are represented by the formula (3) or ( 4), the content of hydroxyl groups is adjusted within the range of 45 to 80 mgKOH/g in terms of the hydroxyl value of the polyureaurethane resin alone. require something. This point will be described later.

The reaction performed in the first step is a reaction represented by the following formula, and is a polyaddition reaction using a 5-membered cyclic carbonate compound and a compound having an amino group as monomer units. This polyaddition reaction generates one urethane bond and one hydroxyl group as shown in the following formula, and by using a compound with two or more functional groups, it becomes a polymer, and a hydroxy polyurethane resin having hydroxyl groups in the polymer side chains. is obtained.

In the above reaction, as shown above, there are two types of cleavage of the 5-membered cyclic carbonate. Therefore, the structure of the hydroxyl group portion in the resulting polyurethane resin is represented by the formulas (1) and (2) shown above. These two types exist randomly.

One of the characteristics of the polyureaurethane resin that can be obtained as described above is that it contains a structure derived from carbon dioxide. Specifically, by synthesizing the five-membered cyclic carbonate compound used in the reaction in the first step from an epoxy compound and carbon dioxide, the resulting resin has an —O—CO— structure in the urethane bond. part is a component derived from carbon dioxide. A polyurethane resin in which carbon dioxide is fixed in its structure is useful as a material for dealing with environmental problems. Specific methods for producing five-membered cyclic carbonate compounds are described in Patent Documents 5, 6, and 7 cited above as prior art. The 5-membered ring cyclic carbonate compound used in the present invention was produced using carbon dioxide as a reaction raw material and using the same reaction conditions, reaction solvents, and catalysts as those described in the literatures listed above. , is a cyclic carbonate compound derived from carbon dioxide as shown in the following reaction formula.

<Reactive component-5-membered ring cyclic carbonate compound used in the first step>
Any five-membered cyclic carbonate compound used in producing the polyureaurethane resin constituting the varnish composition of the present invention has one or more five-membered cyclic carbonate groups in one molecule. can also be used. For example, compounds having a benzene skeleton, an aromatic polycyclic skeleton, a condensed polycyclic aromatic skeleton, and aliphatic or alicyclic compounds can all be used. However, in order to obtain an environmentally friendly ink varnish, which is one of the objects of the present invention, it is preferable to prepare a five-membered cyclic carbonate compound using raw materials that do not contain impurities such as bisphenol A. Even if a bisphenol-type raw material is used, it can be used as long as bisphenol A does not enter the composition as an impurity or a decomposition product. In order to eliminate the above risk of contamination, the polyureaurethane resin that characterizes the varnish composition of the present invention preferably does not contain a chemical structure derived from bisphenol A.

In order to ensure that the polyureaurethane resin does not contain a chemical structure derived from bisphenol A, for example, the 5-membered cyclic carbonate compound used in the reaction in the first step has a 5-membered structure as listed below. A cyclic carbonate compound may be used.

R in the formulas listed below independently represents H or _CH3 .

As the five-membered cyclic carbonate compound used in producing the polyureaurethane resin constituting the present invention, for example, it is possible to use a compound having a structure having an aromatic ring as shown below. However, according to the studies of the present inventors, as described below, it is difficult to say that this resin is optimal as a resin constituting a varnish for gravure printing ink, which is the object of the present invention. That is, according to the studies of the present inventors, in the case of a resin having a structure derived from a five-membered cyclic carbonate compound having an aromatic ring as shown below, if the solid content is about 30%, a nonpolar solvent However, when the solid content is less than 20%, the solubility tends to be poor. Specifically, when applied to ink varnishes for practical gravure printing inks, there are cases where compatibility with resins used in combination is not sufficient, and separation occurs when diluted with ethyl acetate. I don't like it because there is.

<Reactive component used in the first step - amine compound>
Any conventionally known amine compound can be used as the amine compound used in producing the polyureaurethane resin constituting the varnish composition of the present invention. Preferred examples include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane (hexamethylenediamine), 1,8-diaminooctane, 1,10-diaminodecane, 1 , 12-diaminododecane, chain aliphatic polyamines such as diamines derived from dimer acid as described later, norbornanediamine, cycloaliphatic polyamines such as 1,3-(bisaminomethyl)cyclohexane, aromatics such as xylylenediamine Aliphatic polyamines having rings can be mentioned. Because the polyureaurethane resin constituting the varnish composition of the present invention must contain 30% or more by mass of a biomass component resulting from a chemical structure derived from dimer acid as a requirement of d). , preferably a diamine derived from a dimer acid. Commercially available dimer acid-derived diamines include, for example, Priamine 1074 (trade name, manufactured by Croda Japan). Particularly preferred other amines include chain diamines such as 1,6-diaminohexane and 1,8-diaminooctane. According to studies by the present inventors, by using these compounds, more stable and remarkable effects can be obtained.

<Amount of structure derived from carbon dioxide in the resin of definition e)>
Since the polyureaurethane resin constituting the varnish composition of the present invention contains a skeleton obtained by the polyaddition reaction of two types of compounds, the five-membered cyclic carbonate compound and the amine compound described above, the polymer chain is substantially It becomes a structure in which carbon dioxide is incorporated. The amount of the carbon dioxide-derived structure is determined by the combination of the two types of compounds, and is preferably as high as possible within a range that does not impair the required physical properties as an ink varnish. On the other hand, introduction of 1 mol of urethane bonds derived from carbon dioxide generates 1 mol of hydroxyl group, so polyurea urethane resin is selected in consideration of the effect on solubility in the organic solvent used and compatibility with other resins. It is preferable to design In the varnish composition of the present invention, for the purpose of making it a technology that contributes to the reduction of greenhouse gases, as definition e), 9% by mass or more of the weight of the resin is a polyurea urethane resin having a structure derived from carbon dioxide as a raw material. stipulated that it is an essential component.

<Biomass component resulting from chemical structure derived from dimer acid in definition d)>
The polyureaurethane resin constituting the varnish composition of the present invention contains 30% or more by mass of a biomass component resulting from a chemical structure derived from dimer acid, as defined in definition d). The “biomass component resulting from the chemical structure derived from dimer acid” in d), which is one of the factors that define the polyurea urethane resin, is one of the amine compounds used in the polyaddition reaction in the first step described above. 2) means a component having a structure obtained by using a diamine derived from a plant-derived dimer acid. This diamine is produced via dimer acid and is generally available. The method for producing the diamine used above is to obtain a dimer acid, which is a dicarboxylic acid obtained by dimerizing unsaturated fatty acids such as oleic acid and linoleic acid, and then convert the carboxy group of the dimer acid to an amino group. to diamine. The dimer acid is a mixture, since multiple structures are obtained in the dimerization process. In the present invention, a dimer acid whose carboxyl group is converted to an amino group and then hydrogenated to eliminate unsaturated bonds can also be used. The number of carbon atoms in the unsaturated fatty acid used for preparing the dimer acid is not particularly limited, but the preferred unsaturated fatty acid is oleic acid or linoleic acid with 18 carbon atoms. Since these unsaturated fatty acids can be obtained as plant-derived fatty acids, biomass components resulting from dimer acid-derived chemical structures can be easily obtained. Since the varnish composition of the present invention uses a polyureaurethane resin having properties defined as definition d) as an essential component, it is also preferable from the viewpoint of global environmental protection.

The advantage of introducing the dimer acid-derived structure defined in d) into the structure of the polyureaurethane resin constituting the varnish composition of the present invention is that it has the effect of increasing the degree of biomass and softening the resin. The improvement of the solubility of the resin constituting the. One of the important objects of the present invention is to improve the solubility of a polyurethane resin having a hydroxyl group in an acetic acid ester-based organic solvent, which is a general-purpose non-polar solvent, and to improve the compatibility with other resin components added to gravure printing ink. This is an improvement in the compatibility of On the other hand, according to the studies of the present inventors, the polyureaurethane resin having a dimer acid-derived structure improves the solubility in general-purpose organic solvents when used as a component of the varnish composition of the present invention. contribute. Furthermore, since the dimer acid can be produced from a biomass-derived material, it is suitable for providing an environmentally friendly gravure printing ink, which is one of the objects of the present invention. It is suitable as a component of the polyureaurethane resin for ink varnish specified in the present invention.

(Amount of dimer acid-derived component)
It is preferable that the amount of the dimer acid-derived structure introduced into the polyureaurethane resin is as high as possible within a range that does not impair the required physical properties as an ink varnish. In actual use in printing inks, other components are blended, so the biomass degree of ink varnish alone cannot define the biomass degree of printed matter. The polyureaurethane resin, which is an essential component of the varnish composition of the present invention, preferably contains 30% or more by mass of a biomass component derived from dimer acid. More preferably, it is 35% or more.

In the present invention, the degree of biomass (not including pigment) refers to the proportion of solid content derived from biomass components contained in the resin solid component, and is represented by the following formula (A). The hydroxypolyurethane prepared as described above, which is used as an intermediate for the polyureaurethane resin that is an essential component of the varnish composition of the present invention, uses a diamine derived from dimer acid as a raw material. When the biomass content is calculated using the biomass ratio, it contains 30% or more by mass ratio.
Biomass degree (%) = (biomass-derived resin solid content/resin solid content) x 100 (A)

<Abundance ratio of urea bond of definition c)>
The feature of the polyureaurethane resin, which is an essential component constituting the varnish composition of the present invention, is that it has a urea bond in addition to the urethane bond, as defined in c), and the urea bond has a structure derived from an aliphatic isocyanate. and the molar ratio of urethane bond/urea bond in the resin is required to be 10/1 to 10/3. As explained above, the polyureaurethane resin is obtained through the first step and the second step. In the first step, a polyurethane oligomer is synthesized, and the molar ratio of the 5-membered cyclic carbonate compound and the compound having an amino group is adjusted so that the terminal of the molecule is an amino group. The amount of remaining amino groups is converted to urea bonds by the elongation reaction in the second step. According to studies by the present inventors, the urea bond present in the structure of the resin has a strong cohesive force, improves the strength of the resin, and contributes to the strength of the printed coating film and the reduction of surface tack. On the other hand, the strength of the cohesive force reduces the solubility in organic solvents. With respect to this point, the present inventors have made intensive studies and found that it is important to adjust the ratio of the urethane bond obtained in the first step. Specifically, the abundance ratio in the final polyurea urethane resin is such that the molar ratio of urethane bond/urea bond is in the range of 10/1 to 10/3, further 10/2 to 10/3. It is preferable to use a polyureaurethane resin adjusted to be in the range of By using a polyurea urethane resin in which the abundance ratio of urethane bonds and urea bonds is adjusted so that it falls within the above range, it is possible to achieve a balance between the properties of the varnish composition and the properties of the formed printed coating film (adhesive film). be possible.

<Organic Solvent Used for Reaction and Dilution When Obtaining Polyureaurethane Resin>
The reactions in the first and second steps described above are both carried out using a reaction solvent. Depending on the design of the resin, it is possible to synthesize it by appropriately using various solvents capable of dissolving it. For example, the following organic solvents can be used. Specifically, hydrocarbon solvents such as toluene, xylene, ethyl acetate, butyl acetate, propyl acetate, tetrahydrofuran, dioxane, dimethylformamide, ester solvents, ether solvents, methanol, ethanol, propanol, Alcohol-based solvents such as butanol can be used. A method of distilling off the solvent after synthesizing using these solvents as a reaction solvent, and then redispersing and diluting in an acetate-based organic solvent that is essential in the varnish composition of the present invention can also be adopted. However, from the viewpoint of production cost, it is preferable that the synthesized resin solution can be used as it is. Therefore, it is preferable to use an acetic acid ester-based organic solvent such as ethyl acetate, propyl acetate, isopropyl acetate, etc., which is also a constituent of the varnish composition of the present invention, as a reaction solvent in the production of the resin. Considering the hydroxyl group silylation step, which is a part of the first step, it is preferable not to use an alcohol-based solvent as a reaction solvent. The silylation step will be described later.

<Definition a), definition b) and hydroxyl value>
The polyureaurethane resin, which is an essential component of the varnish composition of the present invention, has a hydroxyl group of either structure represented by the above formula (1) or (2), as defined in a). On the other hand, the hydroxyl group is a factor that hinders the improvement of the solubility in the acetate-based organic solvent (non-polar solvent), which is a component of the varnish composition of the present invention, so it is important to control the amount. . The amount of hydroxyl groups generated in the polyaddition reaction in the first step described above depends on the molecular weight of the monomer. However, it is not possible to greatly control the amount of hydroxyl groups to be generated only by adjusting the selection of monomers used in the reaction. In particular, the varnish composition of the present invention requires dissolution of the polyureaurethane resin in the acetic ester solvent, which is an important problem. In order to solve this problem, the present inventors found that by silylating and capping some of the hydroxyl groups generated in the first step, the amount of hydroxyl groups in the resin can be reduced to an appropriately controlled state, As a result, the present inventors have found that the gravure printing ink obtained by using the varnish composition of the present invention is a good one that is adjusted to a range in which the performance as an ink is balanced, leading to the present invention.

Specifically, the polyureaurethane resin constituting the varnish composition of the present invention, as defined in a), has a hydroxyl group having a structure represented by the following formula (1) or (2) in the polymer chain. and further, as defined in b), a portion of the hydroxyl group is a silylated structure represented by the following formula (3) or (4), thereby containing a hydroxyl group The amount should be adjusted within the range of 45 mgKOH/g to 80 mgKOH/g in terms of the hydroxyl value of the polyureaurethane resin alone.

［式（１）～（４）中のＰはいずれもポリマー鎖との結合部を示しており、式（３）又は（４）中のＲは、それぞれ独立に水素又はメチル基を示す。］

[P in formulas (1) to (4) all represent a bond with a polymer chain, and R in formula (3) or (4) each independently represents hydrogen or a methyl group. ]

As described above, the polyureaurethane resin that constitutes the varnish composition of the present invention is capped by silylating some of the hydroxyl groups in the polyurethane resin produced in the first step described above. It is required to have a structure in which the hydroxyl value is adjusted to a specific range. Specifically, it is required that the hydroxyl content of the resin after the second step is adjusted within the range of 45 mgKOH/g to 80 mgKOH/g in terms of the hydroxyl value of the polyureaurethane resin alone. vinegar. In the present invention, in order to form the polyureaurethane resin, which is an essential component, in the above-described first step, a step of silylating hydroxyl groups is carried out. The silylation of the hydroxyl group can be carried out either during or after the synthesis of the polyurethane resin, so the production method is not particularly limited. For example, it can be carried out under the conditions described in Japanese Patent No. 7066664. In order to improve the solubility of the polyhydroxyurethane resin in the acetic ester-based organic solvent, which is a non-polar solvent, which is the object of the present invention, if the silylation amount is too high, the solubility becomes poor. However, the solubility is not sufficiently improved. According to the studies of the present inventors, the "hydroxyl group silylation rate (OH modification rate)" (hereinafter also referred to as silylation rate) performed in the silylation reaction step is the silylation rate of the hydroxyl group of the polyhydroxyurethane resin. is, for example, about 0.3 to 0.7 (30 to 70%). In the present invention, in order to achieve such a silylation rate, as defined in b), the hydroxyl value of the resin after silylation is in the range of 45 mgKOH/g or more and 80 mgKOH/g or less. It is an essential requirement that Although it varies depending on the skeleton of the resin, it is more preferably 50 mgKOH/g to 70 mgKOH/g. Further, according to the studies of the present inventors, the amount of hydroxyl groups in the polyureaurethane resin constituting the varnish composition of the present invention is within the range of the hydroxyl value defined in b), whereby the polyhydroxyurethane resin It is possible to realize a gravure printing ink that can retain the inherent properties of adhesiveness to a substrate and excellent laminating strength.

As described above, in the present invention, by silylating a portion of the hydroxyl groups in the polyurethane resin produced in the first step, the amount of hydroxyl groups in the polyureaurethane resin constituting the varnish composition of the present invention is reduced to b ) is adjusted to be within the range defined by In the second step which follows the first step, the amino-terminated polyhydroxyurethane resin is elongated with isocyanate. This second step does not reduce the amount of hydroxyl groups in the resin. That is, in the second step, both the amino group and the hydroxyl group are functional groups that react with the isocyanate compound, but since the amino group has higher nucleophilic performance than the hydroxyl group, the amino group preferentially reacts. Therefore, even if the isocyanate compound is reacted, the hydroxyl group remains. Therefore, according to the varnish composition of the present invention, it is possible to maintain the adhesiveness to the substrate and the excellent lamination strength, which are the characteristics of the polyhydroxyurethane resin. is possible.

(Isocyanate used in the second step)
The urea bond structure of the polyureaurethane resin, which is an essential component of the varnish composition of the present invention, is a structure derived from conventionally known polyisocyanates such as diisocyanates, as described below. Examples of the polyisocyanate used in the second step include bifunctional aromatic diisocyanates, aliphatic diisocyanates (in the present invention, used in the sense of including alicyclic diisocyanates), and further isocyanate-terminated A structure derived from a polyurethane prepolymer obtained by reacting such that A structure derived from an aliphatic diisocyanate is preferable from the viewpoint of solubility. Examples of aliphatic diisocyanates include methylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate and 1,10-decamethylene diisocyanate, and 1,4-cyclohexylene diisocyanate, 4,4 -methylenebis(cyclohexyl isocyanate), 1,5-tetrahydronaphthalene diisocyanate, isophorone diisocyanate, hydrogenated MDI, hydrogenated XDI and other alicyclic diisocyanate-derived structures.

As the urea bond of the polyurea urethane resin constituting the present invention, a structure derived from a polyfunctional compound using a polyfunctional compound having three or more isocyanate groups is also preferable as a form of introduction of the urea bond. . Since the polyurethane urea resin to which the varnish composition of the present invention is applied is used as gravure printing ink, it preferably has a viscosity of 500 mPa·s to 5000 mPa·s at 25°C. On the other hand, the varnish composition of the present invention needs to be designed so that the polyureaurethane resin can be dissolved in the essential component, the acetic acid ester-based organic solvent. viscosity tends to be low. Therefore, in the varnish composition of the present invention, as a preferred form, a polyisocyanate compound having a trifunctional or higher aliphatic polyisocyanate group (in the present invention, it is used in the sense of including alicyclic polyisocyanate) is used. In combination, a polymer chain having a high molecular weight per molecule is allowed to exist in the polymer solution, thereby adjusting the viscosity to an appropriate range. According to the studies of the present inventors, for example, the blending ratio of the bifunctional and trifunctional isocyanate compounds in the above configuration is bifunctional isocyanate compound: trifunctional isocyanate compound = 100: 0 to 65: 35 mol%. More preferably, the bifunctional isocyanate compound: trifunctional isocyanate compound is about 80:20 to 70:30 mol %.

Examples of tri- or more functional isocyanate compounds necessary for the above structure include isocyanurate-type, biuret-type, and adduct-type isocyanate compounds.

[Viscosity of varnish composition]
As described above, in order to use the polyurethane urea resin obtained in the second step as a varnish composition for gravure printing ink, the viscosity at 25° C. should be about 500 mPa·s to 5000 mPa·s. is preferred. By adjusting the viscosity, gravure printing ink can be applied to an appropriate film thickness and exhibit the designed color and hiding power. Therefore, the viscosity of the resin solution used as the ink varnish is important because it directly affects the viscosity of the ink. factor. If the viscosity is lower than the above range, the viscosity of the ink falls below the practical range, making it difficult to design the ink. On the other hand, if the viscosity is higher than the above range, it is necessary to lower the resin concentration in the ink, and the blending balance with the pigment is lost, which affects the coating strength and color tone of the printed surface. According to studies by the present inventors, it is more preferable that the viscosity at 25° C. is 1000 mPa·s or more.

[Optional Additives]
In the varnish composition for gravure printing ink of the present invention, in addition to the essential components listed above, if necessary, for the purpose of imparting a film reinforcing function, a film plasticizing function, a film formation assisting function, etc. Various additives such as those listed below may be further included. Examples of additives include pigment derivatives, dispersants, chelating agents, waxes, fatty acid amides, plasticizers, wetting agents, leveling agents, antifoaming agents, antistatic agents, viscosity modifiers, trapping agents, antiblocking agents, cross-linking agents, and silane coupling agents.

EXAMPLES The present invention will be specifically described below based on Examples, but the present invention is not limited to these Examples. "Parts" and "%" in Examples and Comparative Examples are based on mass unless otherwise specified.

[Production Example 1] (Preparation of cyclic carbonate compound I)
100% neopentyl glycol diglycidyl ether (trade name: "Denacol EX-211" manufactured by Nagase ChemteX Corporation) having an epoxy equivalent of 138 g/eq was added to a reaction vessel equipped with a stirrer, thermometer, gas inlet tube and reflux condenser. 100 parts of N-methyl-2-pyrrolidone (NMP) and 20 parts of sodium iodide (manufactured by Wako Pure Chemical Industries, Ltd.) were added and uniformly dissolved. The mixture was reacted at 100° C. for 10 hours while carbon dioxide gas (CO ₂ gas) was introduced at a rate of 0.5 L/min while stirring. After completion of the reaction, 400 parts of ethyl acetate and 800 parts of water were added and stirred for 1 hour. After that, the ethyl acetate phase was collected and the solvent was removed by an evaporator to obtain a viscous liquid compound.

IR analysis of the powder obtained using an infrared spectrophotometer (trade name: “FT-720”, manufactured by Horiba, Ltd., hereinafter referred to as FT-IR) revealed that around 910 cm ⁻¹ in the raw material It was found that the absorption peak derived from the epoxy group of 2 disappeared, and a new absorption peak derived from the carbonate group (carbonyl group) was generated near 1800 cm ^-1 . The resulting compound (reactant) was confirmed to be a 5-membered cyclic carbonate compound (compound I) represented by the following formula, which has a carbonate group with a cyclic structure formed by the reaction of an epoxy group and carbon dioxide. . The carbon dioxide content of compound I obtained above is calculated to be 24.1%.

[Production Example 2] (Preparation of cyclic carbonate compound II)
A reaction vessel equipped with a stirrer, a thermometer, a gas inlet tube and a reflux condenser was charged with 1,6 hexanediol diglycidyl ether having an epoxy equivalent of 120 g/eq (trade name: "Epogose HD (D)", manufactured by Yokkaichi Gosei Co., Ltd.). ), 100 parts of N-methyl-2-pyrrolidone (NMP), and 20 parts of sodium iodide (manufactured by Wako Pure Chemical Industries, Ltd.) were added and uniformly dissolved. Under stirring, the reaction was carried out at 100° C. for 10 hours while introducing carbon dioxide gas (CO ₂ gas) at a rate of 0.5 L/min. After completion of the reaction, 400 parts of ethyl acetate and 800 parts of water were added and stirred for 1 hour. After that, the ethyl acetate phase was collected and the solvent was removed by an evaporator to obtain a viscous liquid compound.

IR analysis of the powder obtained using FT-IR revealed that the absorption peak derived from the epoxy group of the raw material around 910 cm ^-1 disappeared, and the absorption derived from the carbonate group (carbonyl group) was newly found around 1800 cm ^-1 . It was found that there was a peak. Therefore, the obtained compound was confirmed to be a 5-membered cyclic carbonate compound (compound II) represented by the following formula, which has a carbonate group with a cyclic structure formed by the reaction of an epoxy group and carbon dioxide. The carbon dioxide content of compound II obtained above is 26.8% (calculated value).

[Example 1] (Production of the varnish composition of the present invention)
100 parts of the 5-membered ring cyclic carbonate compound I obtained in Production Example 1 and hexamethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd. ), 96.3 parts of Priamine 1074 (trade name, Croda Japan Co., Ltd.), and 63.8 parts of ethyl acetate as a reaction solvent, followed by heating under reflux conditions of about 80° C. for 5 hours. reacted. When the resin solution after the reaction was analyzed by FT-IR, the absorption derived from the carbonyl group of the 5-membered cyclic carbonate compound I, which had been observed near 1800 cm ^-1 , completely disappeared, and was newly observed at 1760 cm ^-1. Absorption derived from the carbonyl group of the urethane bond was confirmed near ¹ . This is a prepolymer of _NH2 -terminated hydroxypolyurethane.

Next, without cooling the reaction solution, 22.2 parts of hexamethyldisilazane (product name: SZ-31, manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise over 30 minutes to remove the hydroxyl groups of the hydroxypolyurethane prepolymer. A portion was silylated. After 30 minutes of dropping, FT-IR was measured to confirm that the peak around 933 cm ⁻¹ derived from N—Si had disappeared, and the reaction was terminated. After completion of the reaction, 319.0 parts of ethyl acetate was added as a diluent to the solution containing the resin, and the mixture was cooled to room temperature. Then, while stirring the resin-containing solution after cooling, 18.3 parts of isophorone diisocyanate (manufactured by Evonik Japan) is slowly added dropwise to react the terminal NH ₂ and the isocyanate group to obtain a solution containing a polyureaurethane resin. Obtained. After dropping, FT-IR was measured to confirm that the peak around 2260 cm ⁻¹ derived from the isocyanate group had disappeared, and the reaction was terminated.

When the molecular weight of the obtained polyureaurethane resin was measured by GPC using DMF as a mobile phase, the weight average molecular weight was 44000 (as polystyrene conversion value). GPC measurement was performed using an apparatus GPC-8820 (trade name, manufactured by Tosoh Corporation) and four columns (trade names: "Super AW2500, AW3000, AW4000, AW5000", manufactured by Tosoh Corporation). Further, the hydroxyl value of the polyureaurethane resin measured according to JIS-K 1557-1 was 58 mgKOH/g (solid content conversion value, the same applies hereinafter). The above polyureaurethane resin is designed so that the molar ratio of the constituent urethane bonds and urea bonds is 10/3. Table 1 summarizes the outline of the polyureaurethane resin that characterizes the varnish compositions of Examples and the ratio of ethyl acetate, which is an acetic acid ester-based organic solvent, in the varnish compositions.

[Example 2]
100 parts of the cyclic carbonate compound I obtained in Production Example 1, 19.2 parts of hexamethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 88.9 parts of Priamine 1074 (manufactured by Croda Japan Co., Ltd.), and acetic acid as a reaction solvent 60.0 parts of ethyl were used. Otherwise, the reaction was carried out in the same manner as in Example 1 to obtain a hydroxyurethane prepolymer having NH ₂ at the end.

Next, 22.2 parts of the same hexamethyldisilazane used in Example 1 was dropped and reacted in the same manner as in Example 1 to partially remove the hydroxyl groups of the hydroxypolyurethane prepolymer. Silylated. After completion of the reaction, 300.1 parts of ethyl acetate was added as a diluent to the solution containing the resin, and the mixture was cooled to room temperature. Then, while stirring the cooled solution, 12.2 parts of the same isophorone diisocyanate as used in Example 1 was slowly added dropwise, and the terminal NH ₂ and the isocyanate group were reacted to form a solution containing a polyureaurethane resin. got

FT-IR was measured to confirm that the peak around 933 cm ⁻¹ derived from N—Si had disappeared, and the silylation reaction was terminated. Further, FT-IR was measured, and after confirming that the peak around 2260 cm ⁻¹ derived from the isocyanate group had disappeared after the dropwise addition of isophorone diisocyanate, the reaction was terminated. The molecular weight and hydroxyl value of the polyureaurethane resin obtained above were measured in the same manner as in Example 1. As a result, the weight average molecular weight was 55000 and the hydroxyl value was 65 mgKOH/g. The molar ratio of urethane bonds and urea bonds constituting the polyureaurethane resin is 10/2.

[Example 3]
100 parts of the 5-membered ring cyclic carbonate compound I obtained in Production Example 1, 17.6 parts of hexamethylenediamine as used in Example 1, 81.5 parts of Priamine 1074, and a reaction solvent A prepolymer of NH ₂ -terminated polyhydroxyurethane was obtained in the same manner as in Example 1, except that 56.2 parts of ethyl acetate was used as a. Next, 22.2 parts of the same hexamethyldisilazane used in Example 1 was added dropwise in the same manner as in Example 1 to silylate some of the hydroxyl groups. Then, 281.2 parts of ethyl acetate was added to dilute the resin solution after completion of the reaction, and the solution was cooled to room temperature. Then, while stirring the cooled solution, 6.1 parts of isophorone diisocyanate was slowly added dropwise.

FT-IR was measured after the completion of dropping, and it was confirmed that the peak around 933 cm ⁻¹ derived from N—Si disappeared, and the peak around 2260 cm ⁻¹ derived from the isocyanate group disappeared. Upon confirmation, each reaction was terminated. The molecular weight and hydroxyl value of the resulting polyureaurethane resin were measured in the same manner as in Example 1. As a result, the weight average molecular weight was 59000 and the hydroxyl value was 69 mgKOH/g. The molar ratio of urethane bonds and urea bonds constituting the polyureaurethane resin is 10/1.

[Example 4]
100 parts of the 5-membered cyclic carbonate compound I obtained in Production Example 1, 19.2 parts of hexamethylenediamine and 88.9 parts of Priamine 1074, which are the same as those used in Example 1, and a reaction solvent A prepolymer of NH ₂ -terminated polyhydroxyurethane was obtained in the same manner as in Example 1, except that 59.0 parts of ethyl acetate was used as a. Next, 17.7 parts of the same hexamethyldisilazane used in Example 1 was added dropwise in the same manner as in Example 1 to cause a silylation reaction of some of the hydroxyl groups. Then, 295.2 parts of ethyl acetate was added to dilute the resin solution after completion of the reaction, and the solution was cooled to room temperature. Then, while stirring the cooled solution, 12.2 parts of isophorone diisocyanate was slowly added dropwise.

FT-IR was measured after the dropping was completed, and the peak around 933 cm ⁻¹ derived from N—Si disappeared, and the peak around 2260 cm ⁻¹ derived from the isocyanate group disappeared. , respectively terminated the reaction. The molecular weight and hydroxyl value of the resulting polyureaurethane resin were measured in the same manner as in Example 1. As a result, the weight average molecular weight was 53000 and the hydroxyl value was 80 mgKOH/g. The molar ratio of urethane bonds and urea bonds constituting the polyureaurethane resin is 10/2.

[Example 5]
100 parts of the 5-membered cyclic carbonate compound I obtained in Production Example 1, 19.2 parts of hexamethylenediamine and 88.9 parts of Priamine 1074, which are the same as those used in Example 1, and a reaction solvent A prepolymer of NH ₂ -terminated polyhydroxyurethane was obtained in the same manner as in Example 1, except that 61.0 parts of ethyl acetate was used as a. Next, 26.6 parts of the same hexamethyldisilazane used in Example 1 was added dropwise in the same manner as in Example 1 to silylate some of the hydroxyl groups. Then, 305.1 parts of ethyl acetate was added to dilute the resin solution after completion of the reaction, and the solution was cooled to room temperature. Then, while stirring the cooled solution, 12.2 parts of isophorone diisocyanate was slowly added dropwise.

FT-IR was measured after the completion of dropping, and it was confirmed that the peak around 933 cm ⁻¹ derived from N—Si disappeared, and the peak around 2260 cm ⁻¹ derived from the isocyanate group disappeared. After confirmation, each reaction was terminated. The molecular weight and hydroxyl value of the resulting polyureaurethane resin were measured in the same manner as in Example 1. As a result, the weight average molecular weight was 51000 and the hydroxyl value was 53 mgKOH/g. The molar ratio of urethane bonds and urea bonds constituting the polyureaurethane resin is 10/2.

[Example 6]
100 parts of the 5-membered cyclic carbonate compound I obtained in Production Example 1, 19.2 parts of hexamethylenediamine and 88.9 parts of Priamine 1074, which are the same as those used in Example 1, and a reaction solvent A prepolymer of NH ₂ -terminated polyhydroxyurethane was obtained in the same manner as in Example 1, except that 62.2 parts of ethyl acetate was used as a. Next, 22.2 parts of the same hexamethyldisilazane used in Example 1 was added dropwise in the same manner as in Example 1 to silylate some of the hydroxyl groups. Then, 310.8 parts of ethyl acetate was added to dilute the resin solution after completion of the reaction, and the solution was cooled to room temperature. Then, while stirring the cooled solution, 16.3 parts of HDI adduct type isocyanate (product name: Seikabond C-75N, manufactured by Dainichiseika Kogyo Co., Ltd.) and 8.5 parts of isophorone diisocyanate were slowly added dropwise. That is, the bifunctional isocyanate compound: trifunctional isocyanate compound is about 70:30 mol %.

FT-IR was measured after the completion of dropping, and it was confirmed that the peak around 933 cm ⁻¹ derived from N—Si disappeared, and the peak around 2260 cm ⁻¹ derived from the isocyanate group disappeared. After confirmation, each reaction was terminated. The molecular weight and hydroxyl value of the resulting polyureaurethane resin were measured in the same manner as in Example 1. As a result, the weight average molecular weight was 54000 and the hydroxyl value was 61 mgKOH/g. The molar ratio of urethane bonds and urea bonds constituting the polyureaurethane resin is 10/2.

[Example 7]
100 parts of the 5-membered ring cyclic carbonate compound I obtained in Production Example 1, 16.0 parts of hexamethylenediamine and 103.7 parts of Priamine 1074, which are the same as those used in Example 1, and a reaction solvent A prepolymer of NH ₂ -terminated polyhydroxyurethane was obtained in the same manner as in Example 1, except that 62.9 parts of ethyl acetate was used as a. Next, 22.2 parts of the same hexamethyldisilazane used in Example 1 was added dropwise in the same manner as in Example 1 to silylate some of the hydroxyl groups. Then, 314.7 parts of ethyl acetate was added to dilute the resin solution after completion of the reaction, and the solution was cooled to room temperature. Then, while stirring the cooled solution, 12.2 parts of isophorone diisocyanate was slowly added dropwise.

FT-IR was measured after the completion of dropping, and it was confirmed that the peak around 933 cm ⁻¹ derived from N—Si disappeared, and the peak around 2260 cm ⁻¹ derived from the isocyanate group disappeared. After confirmation, each reaction was terminated. The molecular weight and hydroxyl value of the resulting polyureaurethane resin were measured in the same manner as in Example 1. As a result, the weight average molecular weight was 55000 and the hydroxyl value was 60 mgKOH/g. The molar ratio of urethane bonds and urea bonds constituting the polyureaurethane resin is 10/2.

[Example 8]
70.0 parts of the 5-membered cyclic carbonate compound I obtained in Production Example 1, 27.0 parts of the 5-membered cyclic carbonate compound I obtained in Production Example 2, and the same hexamethylenediamine as used in Example 1 19.2 parts of Priamine 1074, 88.9 parts of Priamine 1074, and _59.3 parts of ethyl acetate as the reaction solvent. Obtained. Next, 22.2 parts of the same hexamethyldisilazane used in Example 1 was added dropwise in the same manner as in Example 1 to silylate some of the hydroxyl groups. Then, 296.4 parts of ethyl acetate was added to dilute the resin solution after completion of the reaction, and the solution was cooled to room temperature. Then, while stirring the cooled solution, 12.2 parts of isophorone diisocyanate was slowly added dropwise.

FT-IR was measured after the completion of dropping, and it was confirmed that the peak around 933 cm ⁻¹ derived from N—Si disappeared, and the peak around 2260 cm ⁻¹ derived from the isocyanate group disappeared. After confirmation, each reaction was terminated. The molecular weight and hydroxyl value of the resulting polyureaurethane resin were measured in the same manner as in Example 1. As a result, the weight average molecular weight was 57000 and the hydroxyl value was 65 mgKOH/g. The molar ratio of urethane bonds and urea bonds constituting the polyureaurethane resin is 10/2.

[Comparative Example 1]
100 parts of the 5-membered ring cyclic carbonate compound I obtained in Production Example 1, 25.6 parts of hexamethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 118.7 parts of Priamine 1074 (manufactured by Croda Japan Co., Ltd.), and a reaction solvent 77.3 parts of ethyl acetate was used as the Otherwise, the reaction was carried out in the same manner as in Example 1 to obtain a prepolymer of _NH2 -terminated hydroxyurethane. Next, 25.6 parts of the same hexamethyldisilazane used in Example 1 was dropped and reacted in the same manner as in Example 1 to silylate some of the hydroxyl groups of the hydroxypolyurethane prepolymer. . After completion of the reaction, the solution containing the resin was diluted by adding 386.7 parts of ethyl acetate as a dilution solvent, and cooled to room temperature. Then, while stirring the solution after cooling, 28.0 parts of the same isophorone diisocyanate as used in Example 1 is slowly added dropwise to react the terminal NH ₂ and the isocyanate group to contain the polyureaurethane resin. A solution was obtained.

FT-IR was measured after the completion of dropping, and it was confirmed that the peak around 933 cm ⁻¹ derived from N—Si disappeared, and the peak around 2260 cm ⁻¹ derived from the isocyanate group disappeared. After confirmation, each reaction was terminated. The molecular weight and hydroxyl value of the resulting polyureaurethane resin were measured in the same manner as in Example 1. As a result, the weight average molecular weight was 35000 and the hydroxyl value was 57 mgKOH/g. The molar ratio of urethane bonds and urea bonds constituting the above polyureaurethane resin is 10/4, and the molar ratio of urea bonds in the structure is higher than that specified in the present invention.

[Comparative Example 2]
100 parts of the 5-membered cyclic carbonate compound I obtained in Production Example 1, 19.2 parts of hexamethylenediamine and 88.9 parts of Priamine 1074, which are the same as those used in Example 1, and acetic acid as a reaction solvent. 58.0 parts of ethyl were used. Otherwise, the reaction was carried out in the same manner as in Example 1 to obtain a prepolymer of NH ₂ -terminated hydroxyurethane. Next, 13.3 parts of the same hexamethyldisilazane used in Example 1 was dropped and reacted in the same manner as in Example 1 to silylate some of the hydroxyl groups of the hydroxypolyurethane prepolymer. did. After completion of the reaction, the solution containing the resin was diluted with 290.2 parts of ethyl acetate and cooled to room temperature. Then, while stirring the cooled solution, 12.2 parts of isophorone diisocyanate was slowly added dropwise to react the terminal NH ₂ with the isocyanate group to obtain a solution containing a polyureaurethane resin.

After the completion of dropping, FT-IR was measured to confirm that the peak around 933 cm ^-1 derived from N-Si disappeared, and that the peak around 2260 cm ^-1 derived from the isocyanate group disappeared. was confirmed, and each reaction was terminated. The molecular weight and hydroxyl value of the obtained polyurethane were measured in the same manner as in Example 1. As a result, the weight average molecular weight was 56,000. Moreover, the hydroxyl value is 115 mgKOH/g, which is higher than the value specified in the present invention. The molar ratio of urethane bonds and urea bonds constituting the polyureaurethane resin is 10/2.

[Comparative Example 3]
100 parts of the 5-membered cyclic carbonate compound I obtained in Production Example 1, 19.2 parts of hexamethylenediamine and 88.9 parts of Priamine 1074, which are the same as those used in Example 1, and acetic acid as a reaction solvent. 62.0 parts of ethyl were used. Otherwise, the reaction was carried out in the same manner as in Example 1 to obtain a prepolymer of NH ₂ -terminated hydroxyurethane. Next, 31.0 parts of the same hexamethyldisilazane used in Example 1 was added dropwise in the same manner as in Example 1, and reacted to partially silylate the hydroxyl groups of the hydroxypolyurethane prepolymer. did. After completion of the reaction, the solution containing the resin was diluted with 310.0 parts of ethyl acetate and cooled to room temperature. Then, while stirring the cooled solution, 12.2 parts of isophorone diisocyanate was slowly added dropwise to react the terminal NH ₂ with the isocyanate group to obtain a solution containing a polyureaurethane resin.

After the completion of dropping, FT-IR was measured to confirm that the peak around 933 cm ^-1 derived from N-Si disappeared, and that the peak around 2260 cm ^-1 derived from the isocyanate group disappeared. was confirmed, and each reaction was terminated. The molecular weight and hydroxyl value of the obtained polyurethane were measured in the same manner as in Example 1. As a result, the weight average molecular weight was 51,000. Moreover, the hydroxyl value is 41 mgKOH/g, which is lower than the hydroxyl value specified in the present invention. The molar ratio of urethane bonds and urea bonds constituting the polyureaurethane resin is 10/2.

[Comparative Example 4]
100 parts of the 5-membered ring cyclic carbonate compound I obtained in Production Example 1, 16.0 parts of hexamethylenediamine and 74.1 parts of Priamine 1074 as used in Example 1, and further as a reaction solvent A reaction was carried out in the same manner as in Example 1 except that 52.5 parts of ethyl acetate was used to obtain a NH ₂ -terminated hydroxyurethane prepolymer. Next, 22.2 parts of the same hexamethyldisilazane used in Example 1 was added dropwise in the same manner as in Example 1, and reacted to partially silylate the hydroxyl groups of the hydroxypolyurethane prepolymer. did.

FT-IR was measured and 262.3 parts of ethyl acetate was added to dilute the solution containing the resin after the completion of the reaction in which it was confirmed that the peak around 933 cm ⁻¹ derived from N—Si had disappeared. The reaction was terminated by cooling to room temperature. The molecular weight and hydroxyl value of the obtained polyurethane were measured in the same manner as in Example 1. As a result, the weight average molecular weight was 70000 and the hydroxyl value was 73 mgKOH/g. The resin constituting this example is a resin having a structure that does not have a urea bond.

Table 2 summarizes the composition containing the polyurethane resin of the comparative example.

<Evaluation>
The varnish compositions of Examples 1 to 8 of the present invention obtained above and printing inks prepared using the varnish compositions were evaluated according to the following methods and criteria. Table 3 summarizes the evaluation results. The resin-containing compositions of Comparative Examples 1 to 4 were also evaluated in the same manner as in Examples, and the results are summarized in Table 4.

(1) Evaluation of viscosity:
To 10 parts each of the resin solutions of Examples 1-8 (solid content 40%) and the resin solutions of Comparative Examples 1-4 (solid content 40%), 3 parts of ethyl acetate was added, and the mixture was stirred and mixed at room temperature for 1 hour. Then, it was stored overnight in a constant temperature bath at 25° C., and a sample for viscosity measurement with a solid content of 30% was prepared for each. The viscosity of each prepared sample was measured using a Brookfield viscometer (manufactured by Tokyo Keiki Co., Ltd.) under conditions of No. 3 rotor and 60 rpm. Using the measured values obtained, evaluation was made on a scale of 4 according to the following criteria. It is particularly preferable that the varnish composition for gravure printing ink targeted by the present invention has a viscosity of 1000 mPa·s or more according to the above-described measurement.

(Evaluation criteria)
◎: 1000 mPa s or more ○: less than 1000 to 500 mPa s or more △: less than 500 mPa s ×: not mixed

(2) Evaluation of dilutability in ethyl acetate:
To 10 parts each of the resin solutions of Examples 1 to 8 (solid content 40%) and the resin solutions of Comparative Examples 1 to 4 (solid content 40%), 10 parts of ethyl acetate was added as a diluting solvent, and the mixture was stirred and mixed for 1 hour. A solution with a solids content of 20% was obtained, and a test sample-1 for dilutability was prepared. Similarly, 10 parts each of the resin solutions of Examples 1 to 8 (40% solids) and 10 parts of the resin solutions of Comparative Examples 1 to 4 (40% solids) were added with 30 parts of ethyl acetate as a dilution solvent. After stirring and mixing for a period of time, a solution with a solid content of 10% was obtained, and a test sample-2 for dilutability was prepared. The prepared test sample-1 and test sample-2 were allowed to stand overnight. After standing, the test sample-1 and the test sample-2 were visually observed to confirm the state of each test sample, and the dilutability was evaluated in three grades according to the following criteria. As an ink varnish, it is desired that separation does not occur even with aging.

(Evaluation criteria)
○: No separation over time (after standing overnight) △: Mixed but settled over time ×: Not mixed (settled after standing for 1 minute)

(3-1) Evaluation of compatibility with other resins-1:
10 parts each of the resin solutions of Examples 1 to 8 (solid content: 40%) and the resin solutions of Comparative Examples 3 and 4 (solid content: 40%), for which the result was "O" in the evaluation item (2) above. 1 part of a commercially available vinyl chloride-vinyl acetate copolymer resin varnish (trade name: Solbin, manufactured by Nissin Chemical Industry Co., Ltd.) and 12 parts of ethyl acetate as a dilution solvent are added as other resins to be used in combination. , and stirred and mixed at room temperature for 1 hour to prepare test samples, respectively. Regarding the test solution at the time of preparation and the test sample left still overnight after preparation, the solubility in other resins was visually observed to confirm the state of each test solution. Then, evaluation was made on a three-grade scale according to the following criteria, and the results are shown in Tables 3 and 4.

(Evaluation criteria)
○: No separation after uniform aging (after standing overnight) △: Mixed but settled over time ×: Not mixed (settled after standing for 1 minute)

(3-2) Evaluation of compatibility with other resins-2:
Compatibility with other resin components used in combination in the same manner as the previously prepared test sample except that 1 part of the following components were added instead of 1 part of Solbin used in Evaluation-1 It was confirmed. That is, as the basic composition, 10 parts each of the resin solutions of Examples 1 to 8 (solid content 40%) and the resin solutions of Comparative Examples 1 to 4 (solid content 40%) are listed below (A) to ( 1) and 12 parts of ethyl acetate as a dilution solvent were added, and the mixture was stirred at room temperature for 1 hour to prepare each test sample. The state of the test sample solution during preparation and the state of the solution after the prepared test sample was left overnight were visually observed, and the compatibility with the components used in combination was evaluated in the same manner as in (1). Three levels of evaluation were made based on the criteria. The results are collectively shown in Tables 3 and 4.

(Other resin components to be used together)
(A) Chlorinated polypropylene (chlorinated PP)
(b) Cellulose resin A (solid content: 20%) having 13.5% acetyl groups, 38% propionyl groups, and 1.3% hydroxy groups in its structure
(c) Cellulose resin B having 2.5% acetyl group, 46% propionyl group and 1.8% hydroxy group in the structure (solid content 20%)

(4) Evaluation of coating surface tack:
The resin solutions of Examples 1 to 8 (solid content: 40%), the resin solutions of Comparative Example 4 (solid content: 40 %) to 10 parts each, 30 parts of ethyl acetate as a diluting solvent, and 2 parts of (c) cellulose resin B used in the compatibility evaluation-2 of (2) above, and mixed with stirring for 1 hour to obtain a resin. A solution was prepared for each. Using each resin solution obtained, each test sample obtained above was coated on a PET film (trade name: “Lumirror T60”, manufactured by Toray Industries, Inc., thickness 100 μm) that had been subjected to corona discharge treatment using a bar coater. A laminate consisting of a PET film and a resin layer was formed by coating the resin so that the thickness of the resin was 5 g/m ² , and drying in an oven heated to 120° C. for 10 minutes. Then, the coated surfaces of the obtained laminate were adhered to each other for 5 seconds and then peeled off for evaluation. The results are summarized in Tables 3 and 4 after three-level evaluation based on the following evaluation criteria.

(Evaluation criteria)
〇: The resin layer can be peeled off without leaving any traces △: The resin layer can be peeled off, but traces remain on the coated surface ×: The coated surfaces stick to each other

≪Ink preparation example and its use≫
(Preparation of varnish containing vinyl chloride acetate resin and varnish containing chlorinated PP resin used together)
20 parts of vinyl chloride resin having a hydroxyl value of 154 mgKOH/g and a vinyl chloride:vinyl acetate:vinyl alcohol ratio of 88:1:11 (molar ratio) and 80 parts of ethyl acetate as a diluting solvent were added and diluted to 2 at room temperature. Stirred for an hour. After confirming that the vinyl chloride acetate resin in a solid state was completely dissolved by visual observation, a vinyl chloride acetate resin varnish was prepared to be used in combination with the varnish composition of the present invention during the preparation of gravure printing ink. Further, in the same manner as above, 20 parts of chlorinated polypropylene (chlorinated PP) having a chlorine content of 41% and 80 parts of ethyl acetate as a dilution solvent were added and stirred at room temperature for 2 hours. After visually confirming that the chlorinated PP in a solid state had completely dissolved, a chlorinated PP resin varnish to be used for ink preparation was prepared.

(Preparation of printing ink)
As the varnish composition, the resin solutions of Examples 1 to 8 (solid content 40%) and the resin solution of Comparative Example 4 (solid content 40%) were used, respectively, and the previously prepared vinyl chloride resin varnish and chlorinated PP were used. A white ink was prepared in the following manner using a resin varnish and a white pigment. The resin solutions of Comparative Examples 1 to 3 were excluded from the printing ink preparation test because they could not be used as printing ink due to poor dispersion of the white pigment. Each white ink was prepared as follows.

23 parts each of the resin solution of Examples 1 to 8 (solid content 40%) and the resin solution of Comparative Example 4 (solid content 40%) were used, 32 parts of the pigment titanium white (rutile type), and the previously prepared salt A mixture composed of 14 parts of vinyl acetate resin varnish (20% solids), 1 part of chlorinated PP resin varnish (20%), and 30 parts of ethyl acetate as a diluent was kneaded in a paint shaker to give a white color. An ink was prepared for each. To 100 parts of each of the white inks prepared as described above, 3 parts of isophorone diisocyanate (IPDI) adduct with a solid content of 30% was added, and after sufficiently stirring and mixing, the same ink used in gravure printing was added. Then, the viscosity of the white ink was adjusted to 16 seconds using a Zahn cup #3. IPDI is an additive for adjusting the viscosity of the varnish. MEK/ethyl acetate/IPA=4/4/2 was used as a diluting solvent when adjusting the viscosity. A printing test was carried out using the white ink for printing obtained as described above. The white ink obtained from the resin solution of Comparative Example 4 had a large tackiness on the ink surface after drying, making it difficult to apply a dry laminating agent, and was not suitable for practical use, so it was excluded from the printing test.

(Printing suitability test method)
Using the resin solutions of Examples 1 to 8 (solid content 40%) as a varnish composition and using the white ink for printing obtained as described above, an ink layer was formed and a printability test was performed. went. Specifically, a corona discharge-treated PET film (trade name: “Ester E5102”, manufactured by Toyobo Co., Ltd., thickness 12 μm) was used as the base material, and the ink layer was dried with a bar coater at an amount of 1 g/m ² . A laminate consisting of a film (substrate) and an ink layer (printing film) was formed by applying white ink for printing so as to be , and then drying in an oven at 70°C. Furthermore, a dry lamination adhesive (trade name: “Seikabond E263/C-75N”, manufactured by Dainichiseika Kogyo Co., Ltd.) was applied to each of the laminates obtained above in a dry coating amount of 3 g/m ² . It was applied and dried by gravure printing so as to have a thickness of 60 μm and was thermocompression bonded using a CPP film (trade name: “Torayfan ZK207” manufactured by Toray Advanced Film Co., Ltd.). After that, aging was performed at 40° C. for 48 hours to obtain a laminate. The film formed by applying white ink for printing with a bar coater as described above is not significantly different from the film formed by gravure printing using white ink. In the printing suitability test of the present invention, basically, a laminate composed of a film (substrate) obtained by coating white ink with a bar coater and an ink layer (printing film) was used as a test sample.

(5) Evaluation of printing suitability:
[Adhesiveness]
The surface of the ink layer (printed film) of the laminate before lamination was subjected to a cellophane tape peeling test, the appearance of the printed film was visually observed, and the evaluation was made on a scale of 4 according to the following criteria. The results are collectively shown in Tables 3 and 4.

(Evaluation criteria)
◎: The print film was not peeled off at all ○: Less than 20% of the print film was peeled off △: 20% or more to less than 50% of the print film was peeled ×: 50% or more of the print film was peeled off

[Boiling suitability]
After heating the laminated laminate in which the printed film surface was laminated in hot water at 90° C. for 30 minutes, the change in appearance was visually observed and evaluated on a scale of 4 according to the following criteria. The results are collectively shown in Tables 3 and 4.

(Evaluation criteria)
◎: No lamination at all ○: Pinhole-shaped lamination △: Delamination occurs in streaks ×: Delamination occurs on the entire surface

[Laminate strength]
A laminate laminate obtained by laminating the printed film surface was heated in hot water at 90° C. for 30 minutes, and then cut into a width of 15 mm to obtain a sample for measurement. Then, using this measurement sample, the 180° peel strength (N / 15 mm) was measured with a peel tester, and compared with the strength of the laminate laminate before heat treatment, evaluated according to the following three-level criteria. The results are summarized in Tables 3 and 4. "Material failure" below means that the base material is destroyed when peeled off, making it impossible to measure, and means that the laminate strength is high.

(Evaluation criteria)
○: Peel strength is 2N or more or material failure △: Peel strength is 1.5N or more to less than 2N ×: Peel strength is less than 1.5N

(6) Evaluation of environmental responsiveness:
The presence or absence of carbon dioxide (CO ₂ ) fixation in the ink forming the ink layer (printing film). Judged.

From the evaluation results of the resin solutions (varnish compositions) of Examples 1-8 shown in Table 3 and the resin solutions (varnish compositions) of Comparative Examples 1-4 shown in Table 4, the following was confirmed. . The resin defined in the present invention constituting the example shows a good result that the dilutability with ethyl acetate (acetic acid ester-based organic solvent), which is a non-polar solvent, is improved, and the solubility in the non-polar solvent is was confirmed to have improved. Furthermore, the resins specified in the present invention constituting the examples have good solution viscosities and have viscosities that can be used as a constituent component of printing inks, so that results showing stable printing suitability can be obtained. did it. In addition, the varnish composition containing the resin specified in the present invention constituting the example can be used in combination with the preparation of printing ink, for example, vinyl chloride-vinyl acetate co-polymer, which is expected to improve resistance to contents, etc. The compatibility with other resins such as polymers was also significantly improved, and it was confirmed that the resins are compatible with various resins in a good state.

On the other hand, as shown in Table 4, in the case of the resin that constitutes the comparative example and does not satisfy the requirements defined in the present invention, the evaluation differs depending on the test items, and good results could not be obtained stably. In particular, as shown in Table 4, many of the resins constituting Comparative Examples had poor dilutability with ethyl acetate and were insufficient for use as two-liquid type gravure inks. In addition, in the case of the resins constituting the comparative examples, even if the dilutability with ethyl acetate is good, the compatibility with other resins such as vinyl chloride-vinyl acetate copolymers is poor, and when diluted It was confirmed that there was a problem that the viscosity was not appropriate. On the other hand, as shown in Table 3, the resins constituting the examples of the present invention have no problem in diluting with ethyl acetate, which is a general-purpose solvent, even when used as a two-liquid type gravure ink. In addition, it was confirmed that a remarkable effect of being compatible with various other resins that are desired to be used in combination can be obtained.

Examples of utilization of the present invention include improved solubility in acetic acid ester-based organic solvents such as ethyl acetate, which is also a general-purpose solvent frequently used in printing inks, and chlorides, which are useful ingredients blended in printing inks in recent years. Disclosed is a varnish composition which is excellent in compatibility when used in combination with other resins such as vinyl-vinyl acetate copolymers and which is particularly useful for gravure printing ink. The varnish composition of the present invention uses a hydroxypolyurethane resin with a unique structure as a component of the varnish composition, but has printing ink properties similar to those of conventional hydroxypolyurethanes, and is expected to be used for conventional purposes. It is a useful thing that can be expected for the application of Furthermore, from the viewpoint of the global environment, the varnish composition of the present invention is also useful as an environmentally friendly product that can contribute to the reduction of greenhouse gases by incorporating carbon dioxide into the resin constituent material, gravure printing with high practical value. It makes it possible to provide binders for inks.

Claims (6)

A varnish composition for gravure printing ink that contains an acetic acid ester-based organic solvent and a polyureaurethane resin as constituent elements, and that can be used in combination with a resin other than the polyureaurethane resin,
Gravure, characterized in that the ratio of the acetic acid ester-based organic solvent in the composition is 60% by mass or more, and the polyureaurethane resin has all of the structures defined in the following a) to e). A varnish composition for printing inks.
a) having a hydroxyl group of any structure represented by the following formula (1) or (2) in the polymer chain,
b) Some of the hydroxyl groups have a silylated structure represented by the following formula (3) or (4), so that the hydroxyl content is converted to the hydroxyl value of the polyureaurethane resin alone. is adjusted within the range of 45 mgKOH / g to 80 mgKOH / g,
c) having a urea bond in addition to the urethane bond, the urea bond is a structure derived from an aliphatic isocyanate, and the molar ratio of the urea bond in the resin is urethane bond/urea bond=10/1 to 10/ 3 and
d) containing 30% or more by mass of a biomass component resulting from a chemical structure derived from dimer acid,
e) 9% by mass or more of the weight of the resin consists of structures derived from the carbon dioxide of the raw material

[P in formulas (1) to (4) all represent a bond with a polymer chain, and R in formula (3) or (4) each independently represents hydrogen or a methyl group. ] 1. The polyureaurethane resin is made from one or more compounds represented by the following formula (5) or (6) as a raw material, and has a chemical structure derived from the raw material in the polymer chain. Varnish composition for gravure printing ink according to 1.

The urea bond is derived from any one or more isocyanate compounds in the group consisting of isophorone diisocyanate, 1,6-hexamethylene diisocyanate and hydrogenated xylylene diisocyanate, and the solution viscosity at 25 ° C. is 500 mPa · 3. The varnish composition for gravure printing ink according to claim 1 or 2, wherein the varnish composition is from s to 5000 mPa·s. The varnish composition for gravure printing ink according to claim 3, wherein the urea bond further comprises a urea bond derived from an isocyanurate-type, biuret-type or adduct-type trifunctional or higher aliphatic polyisocyanate compound. The varnish composition for gravure printing ink according to claim 1 or 2, wherein the proportion of the acetate organic solvent is 90% by mass or more. 3. The gravure printing ink according to claim 1 or 2, further comprising at least one of vinyl chloride-vinyl acetate copolymer or chlorinated polypropylene, or cellulose resin having an acetyl group, a propionyl group and a hydroxy group. varnish composition.