JP2002047327A - Polyurethane resin and printing ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyurethane resin and printing ink having an excellent adhesion with a polyolefin film and required quality characteristics equal to those of an ink containing a conventional polyurethane resin. SOLUTION: The polyurethane resin is obtained by reacting a diisocyanate compound with a compound containing an activated hydrogen group at least shown in the following general formula (1). The printing ink containing the resin is also provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyurethane resin and a printing ink containing at least the resin, and more particularly to a polyurethane resin and a printing ink having excellent adhesiveness to a polyolefin film used for packaging materials.

[0002]

2. Description of the Related Art In general, a printing ink for printing on a plastic film used for a package or the like is required for a packaging material such as a retort product, a chilled product such as a frozen dessert and a cold food, and a snack confectionery depending on a use of the package. Adhesion, heat resistance, cold resistance,
In view of required performances such as oil resistance, water resistance, pressure resistance, pinhole resistance, and content resistance, a one-pack or two-pack printing ink using a polyurethane resin as a binder is used.

[0003] However, printing inks using conventional polyurethane resins do not have sufficient adhesiveness particularly to polyolefins such as polypropylene. Therefore, when using the printed matter alone or when laminating a polyolefin film printed matter obtained by using the above printing ink for the above packaging material and another plastic film by dry lamination or extrusion lamination, However, there is a problem that the adhesive strength of the laminated film is insufficient, and the laminated film peels off at the interface between the polyolefin film and the printing ink, and cannot satisfy the quality required for the packaging material as described above. Therefore, regarding the improvement of the adhesiveness of a printing ink to a polyolefin film, a polyurethane resin in which a polar group such as a hydroxyl group or an amino group is introduced into a terminal or a side chain of the polyurethane resin used for the printing ink has been proposed. At present, they have not yet exhibited sufficient adhesive performance.

[0004]

DISCLOSURE OF THE INVENTION The present invention has the required quality characteristics for packaging materials that are comparable to the performance of conventional printing inks containing a polyurethane resin and has excellent adhesion to polyolefin films. The purpose is to provide polyurethane resin and printing ink.

[0005]

The above object is achieved by the present invention described below. That is, the present invention provides a polyurethane resin obtained by reacting a diisocyanate compound with an active hydrogen compound containing at least a compound represented by the following general formula (1), and a printing ink containing the resin. I will provide a.

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The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, the printing ink containing the above-mentioned polyurethane resin has been found to have the heat resistance, cold resistance, oil resistance, water resistance and water resistance required for packaging materials. It has been found that quality properties such as pressure resistance, pinhole resistance and content resistance are comparable to those of conventional printing inks containing polyurethane resins, and that they have excellent adhesion to polyolefin films.

[0007]

Next, the present invention will be described in more detail with reference to preferred embodiments. As the diisocyanate compound used in the present invention, for example, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,3-bis (isocyanatomethyl)
Alicyclic diisocyanate such as cyclohexane; isopropylene diisocyanate, methylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,
2,4-trimethylhexamethylene diisocyanate,
Aliphatic diisocyanates such as lysine diisocyanate; 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4-diphenylmethane diisocyanate, 1,3-xylylene diisocyanate;
Examples thereof include aromatic diisocyanates such as 1,4-xylylene diisocyanate, diisocyanates such as dimer diisocyanate obtained by converting a carboxyl group of dimer acid into an isocyanate group, and a mixture thereof.
Further, urethane prepolymers having isocyanate groups at both ends can also be used as the diisocyanate compound. For example, a reaction product obtained by reacting a diisocyanate and a polyol with an excess of an isocyanate group can be used. A particularly preferred diisocyanate compound is isophorone diisocyanate.

[0008] An active hydrogen compound to be reacted with a diisocyanate compound is defined as active hydrogen in a molecule of at least two OH groups, SH groups, NH ₂ groups or C ₂ groups.
A known active hydrogen compound having an OOH group or the like can be used. For example, dichlorobenzidine, polyethylene adipate, a polyol compound and the like can be mentioned. Preferred active hydrogen compounds include polyol compounds such as polyether polyols and polyester polyols and mixtures thereof. As a polyol compound,
For example, ethylene glycol, diethylene glycol,
Dipropylene glycol, 1,4-butanediol,
1,6-hexanediol, neopentyl glycol,
Low molecular polyols such as trimethylolpropane; polyether polyols such as polyethylene glycol, polyoxypropylene glycol and polytetramethylene ether glycol; polyester polyols which are reaction products of diols and dibasic acids, for example, 1,4-butane Diols such as diol, 1,5-pentanediol, 1,6-hexanediol and 3-methyl-1,5-pentanediol and dibasic acids such as adipic acid, suberic acid, sebacic acid, isophthalic acid and succinic acid And a lactone-based polyester polyol obtained by ring-opening polymerization of a lactone ring, and a mixture thereof. Examples of other polymer polyols include, for example, polymer polyols such as acrylic polyol, phenolic resin polyol, and epoxy polyol.

A particularly preferred active hydrogen compound is a polyester polyol having a number average molecular weight of 500 to 6000, which is a reaction product of the above diol and a dibasic acid. Preferably, the number average molecular weight is 1000 to 500
0 polyester polyol is used.

The general formula (1) which mainly characterizes the present invention.
The compound represented by is as follows.

Embedded image

The compound of the above general formula (1) is prepared by mixing a polybasic acid anhydride with a compound having a primary or secondary amino group and an alcoholic hydroxyl group in a molar ratio of about 1: 0.9 to 1.
It is obtained by reacting with 1. Examples of the acid anhydride of the polybasic acid include, for example, phthalic anhydride, maleic anhydride, succinic anhydride, tetrahydrophthalic anhydride, methylhydrophthalic anhydride, methylhexahydrophthalic anhydride, and the like, and mixtures thereof. No. Particularly preferred acid anhydrides are succinic anhydride and maleic anhydride.

Examples of the compound having a primary or secondary amino group and an alcoholic hydroxyl group include monoethanolamine, monoisopropanolamine, 4-amino-1-butanol, mono-s-butanolamine, and the like.
3-amino-1-propanol, 2-amino-2-methyl-1-propanol (AMP), 2-amino-3-methyl-1-butanol, 2-amino-2-ethyl-1,
3-propanediol (AEPD), 2-dimethylamino-2-methyl-1-propanol (DMAMP) and the like, and N-monoalkyl-substituted (C ₁ -C ₄ ) or N-aryl of these alkanolamines Substituent, diethanolamine, diisopropanolamine,
Di-s-butanolamine and the like, and mixtures thereof. Other examples include unsaturated aliphatic, alicyclic, aromatic, and cyclic derivatives having a primary or secondary amino group and an alcoholic hydroxyl group. Particularly preferred amino alcohol compounds are monoethanolamine,
Monoisopropanolamine and 4-amino-1-butanol.

The compound represented by the general formula (1) is
It is used as a part of the active hydrogen compound, and its use amount is 0.1 to 7 when the total amount of the active hydrogen compound is 100 mol.
It is used in a proportion of 0 mol, preferably in a proportion of 10 to 30 mol. When the amount of the compound represented by the general formula (1) exceeds the above upper limit, a thickening phenomenon occurs during the production of the polyurethane-based resin, and when used as a binder for a printing ink, the printability as a printing ink decreases. On the other hand, if it is less than the lower limit, when the obtained polyurethane resin is used as a binder for printing ink, there is a problem that the adhesiveness to a polyolefin film is reduced. The compound represented by the general formula (1) may be added to the urethane prepolymer of terminal isocyanate, which is a reaction product of a diisocyanate compound and an active hydrogen compound, or may be used simultaneously with the above three components to form the polyurethane resin of the present invention. Synthesis may be performed.

The reaction ratio (equivalent ratio) of the above-mentioned diisocyanate compound and an active hydrogen compound containing the compound represented by the above general formula (1) is such that the isocyanate is 1.2 to 3.0 with respect to 1 equivalent of active hydrogen. Equivalent, preferably 1.5
A urethane prepolymer having a terminal isocyanate is synthesized at a ratio of up to 2.5 equivalents, and the molecular weight is increased with a chain extender to obtain a polyurethane resin. When the use amount of the diisocyanate exceeds the above upper limit, when the obtained polyurethane resin is used for the printing ink, there is a problem that the adhesion of the printing ink to the plastic film is reduced. When used, there is a problem that the printing film is blocked.

The polyurethane resin of the present invention is prepared by reacting the above-mentioned diisocyanate compound with an active hydrogen compound containing the compound of the general formula (1), and optionally, using a chain extender or a reaction terminator of the urethane prepolymer. Use and synthesize. Examples of the chain extender include diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, isophoronediamine, dicyclohexylmethane-4,4-diamine, 2-hydroxyethylethylenediamine, and 2-hydroxypropylethylenediamine; And the like, and mixtures thereof. As a reaction terminator,
Examples include dialkylamines such as di-n-butylamine, alcohols such as ethanol and isopropyl alcohol, and mixtures thereof. The polyurethane resin of the present invention is preferably obtained as an organic solvent solution having a resin solid content of about 30% by weight. The thus obtained polyurethane resin of the present invention has a concentration of 30% by weight (solvent: methyl ethyl ketone, 25% by weight).
C) is preferably 300 to 1,500 mPa · s, and the resin has a number average molecular weight of 10,000.
It is preferably from 0 to 50,000.

The printing ink of the present invention comprises the polyurethane resin of the present invention prepared by converting the above-mentioned polyurethane resin into an aromatic solvent such as toluene and xylene, a ketone solvent such as acetone, methyl ethyl ketone and methyl isobutyl ketone, methanol, ethanol and isopropyl alcohol. , N-butanol or the like, or an ester solvent such as ethyl acetate or butyl acetate or a mixed solvent thereof. The preferred resin concentration is 20 to 40% by weight.

The printing ink of the present invention may further contain, if necessary, a pigment, a diluting solvent, a dispersant, an antiblocking agent, a plasticizer, a surfactant, a silane coupling agent, a coupling agent such as a titanium coupling agent, Additives such as inorganic fillers such as clay and microsilica, and stabilizers such as antioxidants, heat stabilizers, and hydrolysis stabilizers may be added as long as the objects of the present invention are not hindered. Examples of the pigment include inorganic pigments such as titanium oxide, calcium carbonate, barium sulfate, alumina white, zinc white, ultramarine, navy blue, red iron oxide, carbon black, aluminum powder, brass powder, and β-oxynaphthoate-based, arilide Insoluble azo pigments such as phthalocyanine blue, sulfonated copper phthalocyanine blue, metal-free phthalocyanine blue, quinacridone, dioxazine, pyranthrone, anthantrone, indanthrone, etc. And organic pigments such as polycyclic and heterocyclic pigments such as anthrapyrimidine, flavantron, thioindigo, anthraquinone, perinone, perylene, and isoindolino pigments. The printing ink of the present invention in the case where no pigment is added can be used as an overcoating agent such as OP varnish.

The printing ink of the present invention can be gravure-printed on a plastic film, for example, a plastic film such as a polypropylene film, a polyethylene film, a polyester film, or a nylon film by a usual method. The adhesion of the coating to the film is good. Further, after printing and drying on the film, a coated surface coated with a urethane-based, titanium-based, imine-based anchor agent on the printed surface,
Or low density polyethylene, ethylene-
Laminate processing by extruding vinyl acetate copolymer or the like, or applying a urethane-based adhesive to the printing surface with a gravure roll coater or reverse roll coater at 1.5 to 2.0 g / m ² (solid content) After evaporating and drying the solvent, another plastic film can be laminated and dry-laminated. In particular, the adhesiveness of the stretched polypropylene film printed matter printed with the printing ink of the present invention to other plastic films is excellent.

[0019]

Next, the present invention will be described more specifically with reference to examples and comparative examples. The present invention is not limited to these examples and the like. In the description, “parts” or “%” is based on weight.

EXAMPLE 1 300 parts of methyl ethyl ketone and 10 parts of succinic anhydride were charged into an apparatus equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube, and dissolved at 50 ° C. 1 part was dropped and reacted for 1 hour. Next, 800 parts of a polyester polyol having a number average molecular weight of 2,000 obtained from adipic acid and 3-methyl-1,5-pentanediol, and isophorone diisocyanate 22
Two parts were charged and reacted at 80 ° C. for 8 hours under a nitrogen atmosphere. Next, 85.2 parts of isophoronediamine, di-n-
To a mixture of 6.5 parts of butylamine, 880 parts of toluene and 880 parts of isopropyl alcohol, 1838 parts of the above reaction product solution was added, and the mixture was reacted at 50 ° C. for 4 hours.
A polyurethane resin solution of the present invention (viscosity: 600 mPa · sat at 25 ° C.) having a solid content of 30% was obtained. The number average molecular weight of this polyurethane resin was about 30,000.

Comparative Example 1 A polyester polyol 800 having a number average molecular weight of 2,000 obtained from adipic acid and 3-methyl-1,5-pentanediol was placed in an apparatus equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube. , 17 parts of 1,4-butanediol and 222 parts of isophorone diisocyanate were charged and reacted at 80 ° C. for 8 hours under a nitrogen atmosphere. Next, 400 parts of methyl ethyl ketone and 400 parts of toluene
Was added to obtain a homogeneous solution of the reaction product. Next, 85.2 parts of isophoronediamine, 6.5 of di-n-butylamine.
Parts, 478 parts of toluene, 478 parts of methyl ethyl ketone,
To a mixed solution of 878 parts of isopropyl alcohol, 1838 parts of the above reaction product solution was added and reacted at 50 ° C. for 4 hours, and a polyurethane resin solution of a comparative example having a solid content of 30% (viscosity 700 mPa · sat 25 ° C.) I got The number average molecular weight of this polyurethane resin is about 30,000.
Met.

Example 2 The following components were well mixed and dispersed in a commonly used disperser to prepare a printing ink of the present invention. Titanium oxide 30 parts Polyurethane resin (solid content 30% solution of Example 1) 30 parts Methyl ethyl ketone 20 parts Toluene 10 parts Isopropyl alcohol 10 parts

Comparative Example 2 The following components were well mixed and dispersed in a commonly used dispersing machine to prepare a printing ink of Comparative Example. Titanium oxide 30 parts Polyurethane resin (solid content 30% solution of Comparative Example 1) 30 parts Methyl ethyl ketone 20 parts Toluene 10 parts Isopropyl alcohol 10 parts

Using each of the printing inks obtained above, printing was performed on a stretched polypropylene film, polyester film, and nylon film that had been corona-treated with a simple gravure printing machine. After printing and drying, the printed matter was allowed to stand for one day. The adhesiveness of the printing ink was evaluated by the following measurement method.

(Adhesion) After leaving the above printed materials for one day, a commercially available cellophane tape is pressed against the printed surface of each printed material by finger pressure, and rapidly peeled off at an angle of 90 degrees to remove the printed surface. The state of peeling of the ink was determined based on the following criteria. Table 1 shows the evaluation results. Evaluation point 5: No peeling of the printed film was observed at all. 4: After peeling, the presence of more than 90% of the printed film is observed. 3: After peeling, the presence of more than 50 to 90% of the printed film is recognized. 2: After peeling, the presence of more than 10 to 50% of the printed film is recognized. 1: After peeling, the presence of 10% or less of the printed film is recognized.

[0026]

[Table 1] Table 1 Adhesiveness

Examples 3 to 6 The main synthesis raw materials in Example 1 were changed as shown in Table 2 below, and the amounts used were the same as in Example 1, except that the amounts were the same as in Example 1. 3 to 6 of the polyurethane resin solution of the present invention (solid content 30%) were obtained.

[Table 2] Table 2 Synthesis of polyurethane resin Unit of viscosity: mPa · s

Examples 7 to 10 Instead of the polyurethane-based resin solution in Example 2, each of the polyurethane-based resin solutions in Examples 3 to 6 was used. Was obtained. When evaluated in the same manner as in Example 2, excellent results were obtained for all the printing inks as in Example 2.

[0029]

According to the present invention, a printing ink having excellent adhesion to a polyolefin film can be provided by using the polyurethane resin of the present invention as a binder for a printing ink. In addition, the printing ink of the present invention has a required quality of packaging material equal to or higher than that of a conventional printing ink containing a polyurethane resin, and has good workability because it is a one-pack type printing ink.
The range of choices for printing inks for packaging materials is expanded.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J034 BA05 BA06 BA07 BA08 CA01 CA03 CA04 CA11 CA23 CA24 CA32 CB01 CB02 CB03 CC01 CC05 CC09 DA01 DA05 DB03 DB04 DF01 DF11 DF14 DF15 DF16 DF19 DF20 DG01 DG02 DG03 DG04 DG04 HA06 HA07 HC01 HC02 HC03 HC09 HC11 HC12 HC22 HC46 HC52 HC61 HC63 HC64 HC66 HC67 HC71 HC73 QA05 RA07 4J039 AE04 BA04 BA12 BA16 BA18 BA31 BA32 BA35 BA37 BC03 BC04 BC07 BC08 BC16 BC18 BC22 BC23 BC39 BC60 BE01 BE12 BE22 EA36 FA02 GA03

Claims (6)

[Claims] 1. A polyurethane resin obtained by reacting a diisocyanate compound with an active hydrogen compound containing at least a compound represented by the following general formula (1). Embedded image 2. The polyurethane resin according to claim 1, wherein the diisocyanate compound is a urethane prepolymer having isocyanate groups at both ends. 3. The compound according to claim 1, wherein the compound represented by the general formula (1) is a reaction product of a polybasic acid anhydride and a compound having a primary or secondary amino group and an alcoholic hydroxyl group. The polyurethane resin as described. 4. The compound represented by the general formula (1) accounts for 0.1 to 70 mol% of the active hydrogen compound.
Polyurethane-based resin described in 1. 5. The diisocyanate compound is isophorone diisocyanate, the active hydrogen compound is a polyester polyol having a number average molecular weight of 500 to 6,000, and the compound of the general formula (1) is succinic anhydride or maleic anhydride and monoethanol. The polyurethane resin according to claim 1, which is a reaction product with an amine, monoisopropanolamine or 4-amino-1-butanol. 6. A printing ink comprising at least the polyurethane resin according to claim 1. Description: