JPH03119069A - Binder for printing ink - Google Patents

Abstract

PURPOSE:To provide a binder capable of giving printing inks with high adhesivity to various kinds of plastic film, boiling resistance, etc., comprising a polyurethane containing a specified amount of specific butadiene/acrylonitrile copolymer unit. CONSTITUTION:The objective binder comprising a polyurethane containing, in the resinous solid component, 20-90 (pref. 30-80)wt.% of butadiene/acrylonitrile copolymer unit 700-10000 (pref. 1000-6000) in number-average molecular weight made from (A) 10-30 (pref. 15-25)wt.% of acrylonitrile and (B) 90-70 (pref. 85-75)wt.% of butadiene.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a binder for printing ink.

[Prior Art/Problems to be Solved by the Invention] In recent years, with the diversification of packaged items and the advancement of packaging technology, various plastic films have been developed as packaging materials. It has come to be used by selecting it as appropriate. By the way, when plastic films are used as packaging materials, printing is applied to the plastic films for decoration or surface protection, and printing inks for such printing have good adhesion to these various plastic films. Increasingly, advanced performance is required. Conventionally, polyurethane has been widely used as a printing ink binder used in such printing inks. In general, printing inks that use polyurethane as a binder have excellent adhesion to polyester and nylon films, but their adhesion to polyethylene and polypropylene films, which are general-purpose films, is insufficient. When printing on or polypropylene film, a two-component reactive ink containing polyurethane and a polyisocyanate compound is used to supplement adhesive strength. However, two-component reactive inks require a curing agent to be added immediately before printing, making them inconvenient to handle, and they also have the disadvantage of being fairly limited in terms of pot life (pot life). . For this reason, various research and development efforts have been conducted in the industry on polyurethane, which has good adhesion to various plastic films and can be used as a binder for one-component inks without the need to incorporate polyisocyanate compounds. Adhesion has been improved to some extent. However, when the above-mentioned wave-type ink is used for printing a plastic film used as a packaging base material, which is subjected to boil sterilization, retort sterilization, etc. after food packaging, such printed matter has boil resistance, There is a problem that retort resistance (hereinafter referred to as boil resistance) is still poor. Therefore, it is difficult to use one-component inks in fields where boiling resistance is required, so two-component reactive inks containing polyisocyanate compounds are still the mainstream, despite having the above-mentioned drawbacks. is the current situation.

[Means for Solving the Problems] The present inventors have solved the above-mentioned problems, and have excellent adhesion and boiling resistance to various plastic films such as polyester, nylon, polyethylene, and polypropylene as printing substrates. As a result of extensive research aimed at providing a binder for one-component printing ink, we found that when polyurethane having a specific butadiene/acrylonitrile copolymer unit is used as a binder for printing ink, the problems of the prior art described above can be overcome. They found a solution to all the problems and completed the present invention. That is, the present invention uses 10 to 30% by weight of acrylonitrile.
and butadiene/acrylonitrile copolymer units consisting of 90 to 70% by weight and having a number average molecular weight of 700 to 10,000 in the resin solid content.
The present invention relates to a binder for printing ink, characterized in that it contains 0% by weight of polyurethane. As mentioned above, the polyurethane used in the printing ink binder of the present invention contains 10 to 30% by weight of acrylonitrile (hereinafter simply referred to as %) and 90 to 90% by weight of butadiene.
It is a polyurethane having 70% butadiene/acrylonitrile copolymer units. Preferably, it is a polyurethane having a butadiene/acrylonitrile copolymer unit consisting of 15 to 25% acrylonitrile and 85 to 75% butadiene. Here, if the proportion of acrylonitrile in the butadiene/acrylonitrile copolymer unit is less than 10%, boil resistance etc. tend to decrease when used as a one-component ink;
%, the adhesion to plastic films tends to decrease. In addition, the number average molecular weight of the butadiene/acrylonitrile copolymer unit is 700 to 10,000,
The grain size is preferably 1,000 to 6,000. If the number average molecular weight is less than 700, the boiling resistance when used as a one-component ink tends to decrease, and if it exceeds 10,000, the adhesiveness to plastic films tends to decrease. Further, the butadiene/acrylonitrile copolymer unit may have any structure as long as it is shown above. That is, the acrylonitrile unit may form either a random copolymer or a block copolymer with the butadiene unit. In addition, the butadiene unit in the copolymer unit may form a copolymer with either 1.4 bonds or 1.2 bonds, and 1,4 bonds and 1.2 bonds may form a random copolymer or A block copolymer may be formed. The content of butadiene/acrylonitrile copolymer units in the polyurethane is 20% in the solid content of the polyurethane resin.
-90% is preferable, and 30-80% is more preferable. If the content is less than 20%, the boiling resistance when used as a wave ink tends to decrease, and if it exceeds 90%, the adhesion to plastic films tends to decrease. be. The polyurethane of the present invention is generally obtained by reacting a polymer polyol, a diisocyanate compound, a button extender, etc., and there are no restrictions on the method of introducing the butadiene/acrylonitrile copolymer unit into the polyurethane. Any method may be used as long as it can produce a polyurethane having the above-mentioned structural units, but for example, the following method may be used. For example, a polyol compound having a hydroxyl group at the end of a butadiene/acrylonitrile copolymer unit may be used as the polymer polyol component. Specifically, this polyol compound is obtained by copolymerizing butadiene and acrylonitrile, and is commercially available under the trade name HYCARHTBN (B, F, GoodrichC).
(manufactured by chemical Co.), product name: POLYBD
Examples include CN-15 (manufactured by ARCO Chemical Co.). Furthermore, a polyamine compound having an amino group at the end of a butadiene/acrylonitrile copolymer may be used as the polyamine as the chain extender component. Specifically, this polyamine compound is obtained by copolymerizing butadiene and acrylonitrile, and is commercially available under the trade name HYCARATBN (B, F, Goodri
ch Chemical Co., Ltd.). In the present invention, as the polymeric polyol component, in addition to the polyol compound having the butadiene/acrylonitrile copolymer unit, various known compounds generally known as polymeric polyol components of polyurethane are used in combination. For example, ethylene oxide, propylene oxide,
Polyether polyols such as polymers or copolymers such as tetrahydrofuran; ethylene glycol, diethylene glycol, triethylene glycol, 1.2-propanediol, 1.3-propanediol, 1.3-
Butanediol, 1,4-butanediol, neopentyl glycol, bentanediol, 3-methyl-1,5
- Various known saturated and unsaturated low molecular weight glycols such as bentanediol, hexanediol, octanediol, 1,4-butynediol, and dipropylene glycol, or n-butylglycidyl ether, 2-ethylhexylglycidyl ether, etc. Alkyl glycidyl ethers, glycidyl esters of carboxylic acids such as persatic acid glycidyl ester, adipic acid, maleic acid, fumaric acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, oxalic acid, malonic acid, glutaric acid. Polyester polyols obtained by dehydration condensation of acid, dibasic acids such as pimelic acid, azelaic acid, sebacic acid, and speric acid, or their corresponding acid anhydrides and dimer acids; ring-opening polymerization of cyclic ester compounds. Various other known polymer polyols commonly used in the production of polyurethane, such as polycarbonate polyols, polybutadiene glycols, and glycols obtained by adding ethylene oxide or propylene oxide to bisphenol A. can be given. In addition, in the case of a polymer polyol obtained from glycols and dibasic acid among the polymer polyol components,
Up to 5 mol% of the glycols can be substituted with the following various polyols. For example, glycerin, trimethylolpropane, trimethylolethane, 1,2
．． Examples include 6-hexanediol, 1,2,4-butanetriol, sorbitol, and pentaerythritol. The number average molecular weight of the polymer polyol is appropriately determined taking into consideration the solubility, drying properties, blocking resistance, etc. of the polyurethane obtained, and is usually within the range of 700 to 1oooo, preferably 1000 to 6000. good. When the number average molecular weight is less than 700, printability tends to decrease due to a decrease in solubility, and when it exceeds too much, drying properties and blocking resistance tend to decrease. The polymer polyol may be partially substituted with a low-molecular polyol, such as various low-molecular glycols used in the production of the polymer polyol, to the extent that the polyurethane has the performance necessary for use as a printing ink binder. You can. In this case, the amount of low molecular weight glycol is preferably 20% or less, more preferably 10% or less, based on the total polyol component. If the proportion of the low molecular weight glycol exceeds 20%, the solubility in a diluting solvent and the adhesion of the obtained ink composition to a plastic film tend to decrease. In the present invention, various known aromatic, aliphatic, or alicyclic diisocyanates can be used as the diisocyanate compound. For example, 1,5-naphthylene diisocyanate, 4.4/-diphenylmethane diisocyanate, 4,4' diphenyldimethylmethane diisocyanate, 4,47-dibenzylisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene Diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4
-diisocyanate, hexamethylene diisocyanate, 2,2.4-trimethylhexamethylene diisocyanate, 2.4.4-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexyl Representative examples include methane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, m-tetramethylxylylene diisocyanate, and dimer diisocyanate, which is obtained by converting the carboxyl group of dimer acid into an isocyanate group. It can be given as In the present invention, as a chain extender component, in addition to the polyamine compound having a butadiene/acrylonitrile copolymer unit, various known chain extenders can be used in combination. Examples include ethylenediamine, propylenediamine, hexamethylenediamine, triethylenetetramine, diethylenetriamine, isophoronediamine, and dicyclohexylmethane-4,4'-diamine. Others include 2-hydroxyethylethylenediamine, 2-hydroxyethylpro and diamine, di-2-hydroxyethylethylenediamine,
Diamines having a hydroxyl group in the molecule such as di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine, and carboxyl groups of low molecular weight glycols and dimer acids explained in the above section of polyester diols. Typical examples include dimer diamine converted into an amino group. Furthermore, a chain terminator can also be used if necessary. Examples of such chain terminators include dialkylamines such as di-n-butylamine, and alcohols such as ethanol and isopropyl alcohol. There are no particular restrictions on the method for producing polyurethane, and it may be produced in a manner similar to the method for producing polyurethane on a boat. For example, a polymer polyol component and a diisocyanate compound are reacted under conditions in which an excess of isocyanate groups is present to prepare a prepolymer (preferably isocyanate content: 0.5 to 10%) having isocyanate groups at the terminals of the polymer polyol. A two-step process in which the polymeric polyol component, diisocyanate compound, chain extender, and optionally chain terminator are reacted in a suitable solvent with a chain extender and optionally a chain terminator. Although any of the one-stage methods in which the polymers are reacted all at once can be employed, it is preferable to employ the two-stage method since it is easier to obtain a homogeneous polymer solution. When producing the polyurethane used in the present invention by a two-step process, the conditions for reacting the polymeric polyol component and the diisocyanate compound are not particularly limited, except that the inocyanate groups are in excess; It is preferable to react so that the equivalent ratio of isocyanate groups is in the range of 1/1.2 to 1/3. Furthermore, the conditions for reacting the obtained prepolymer with a chain extender and a chain terminator used as necessary are not particularly limited.
The total equivalent of active hydrogen that can react with the isocyanate group in the chain extender is preferably within the range of 0.5 to 2.0 equivalents (especially when the active hydrogen-containing group is an amino group). (preferably within the range of 0.5 to 1.3 equivalents). If the active hydrogen is less than 0.5 equivalents, the drying properties, blocking resistance, and film strength are insufficient, and if the active hydrogen is in excess of 2.0 equivalents, the chain extender is unreacted. The odor tends to remain on printed matter. In these manufacturing methods, the solvents usually used are:
Benzene, a well-known solvent for printing inks;
Aromatic solvents such as toluene and xylene; Alcohol solvents such as methanol, ethanol, isopropanol, and n-butanol; Ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; Ester solvents such as ethyl acetate and butyl acetate. These can be used alone or in a mixture of two or more. The number average molecular weight of the polyurethane of the present invention obtained as described above is preferably in the range of 5,000 to 100,000. When the number average molecular weight is less than 5000, the drying properties, blocking resistance, film strength, oil resistance, etc. of printing inks using this as a vehicle tend to decrease,
On the other hand, if it exceeds 100,000, the viscosity of the polyurethane resin solution (binder) tends to increase and the gloss of the printing ink tends to decrease. In addition, the resin solid content concentration of the polyurethane resin solution is not particularly limited, but may be determined appropriately taking into consideration workability during printing, and is usually 15 to 6.
0% by weight, viscosity is 50~l O0000c P/2
It is practically preferable to adjust the temperature within the range of 5°C. Further, in the present invention, in addition to the polyurethane which is the main component of the present invention, the following resins may be used as subcomponents as the binder of the present invention. Examples include polyurethanes other than those of the present invention, polyamides, nitrocellulose, polyacrylic esters, polyvinyl chloride, copolymers of vinyl chloride and vinyl acetate, rosin resins, ketone resins, and the like. The binder of the present invention is prepared by appropriately blending coloring agents, solvents, and, if necessary, surfactants, waxes, and other additives to improve ink fluidity and ink surface film. A printing ink composition can be manufactured by kneading using an ink manufacturing apparatus. The amount of the binder of the present invention in the printing ink composition is preferably such that the resin solid content is 3 to 20% by weight. The present invention will be described in detail below with reference to Production Examples, Examples, and Comparative Examples, but the present invention is not limited to these Examples. Manufacturing example! A liquid butadiene/acrylonitrile copolymer with a hydroxyl value of 34 (trade name POLYBD CN-15, A
RCO Chemical Co., Ltd., 1000 parts of acrylonitrile containing 15% by weight) and 133 parts of isopolone diisocyanate were reacted at 130'e for 6 hours under a nitrogen stream to produce a prepolymer containing free isocyanate with a fi of 2.13%, followed by methyl ethyl ketone 815. 1 part was added to form a homogeneous solution of urethane prepolymer. Next, 1948 parts of the urethane prepolymer solution was added to a mixture consisting of 38.7 parts of isophorone diamine, 15.3 parts of di-n-butylamine, 1032 parts of methyl ethyl ketone and 923 parts of isopropyl alcohol, and then 50 parts of the urethane prepolymer solution was added.
The reaction was carried out at ℃ for 3 hours. The polyurethane resin solution thus obtained (hereinafter referred to as resin solution A) had a resin solid content concentration of 30% and a viscosity of 1100 cP/25°C. Further, the number average molecular weight of the polyurethane resin was 21,000. Production Example 2 A liquid butadiene/acrylonitrile copolymer with a hydroxyl value of 34 (trade name POLYBD CN-15, A
RCO Chemical Co., acrylonitrile content 15% by weight) 300 parts, poly(1,
700 parts of 2-propylene adipate) glycol and 195 parts of isophorone diisocyanate were charged and reacted at 130°C for 6 hours under a nitrogen stream to produce a prepolymer with a free isocyanate content of 2.99%, and then 815 parts of methyl ethyl ketone was added to produce a urethane prepolymer. A homogeneous solution was obtained. Next, 64.7 parts of isophorone diamine, 11.5 parts of di-n-butylamine, and 1 part of methyl ethyl ketone were added.
2010 parts of the urethane prepolymer solution was added to a mixture consisting of 162 parts and 989 parts of isopropyl alcohol, and then reacted at 50° C. for 3 hours. The polyurethane resin solution thus obtained (hereinafter referred to as resin solution B)
has a resin solid concentration of 30% and a viscosity of 720 cP.
/25℃. Further, the number average molecular weight of the polyurethane resin was 26,000. Production Example 3 In a round bottom flask equipped with a stirrer, a thermometer, and a nitrogen gas inlet tube, poly(butylene adipate) glycol i ooo part with a hydroxyl value of 56 and isophorone diincyanate 2
22 parts were charged and reacted at 100°C for 6 hours under a nitrogen stream to contain free isocyanate. After producing a 3.36% prepolymer, 815 parts of methyl ethyl ketone was added to form a homogeneous solution of urethane prepolymer. Next, a liquid butadiene/acrylonitrile copolymer having an amine value of 62 (trade name: Hycar ATBN, BFGoodrich) was used.
Chemical Co. (Acrylonitrile content: 16.5% by weight) 1507
．． 4 parts, 35.7 parts of di-n-butylamine, 3486 parts of methyl ethyl ketone, and 215 parts of isopropyl alcohol.
Add the urethane prepolymer solution to a mixture consisting of 1 part 2
037 parts were added thereto, followed by reaction at 50° C. for 3 hours. The polyurethane resin solution thus obtained (hereinafter referred to as resin solution C) has a resin solid content concentration of 30% and a viscosity of 38%.
It was 0 cP/25°C. Further, the number average molecular weight of the polyurethane resin was 19,000. Production Example 4 Liquid polybutadiene with a hydroxyl value of 47 (trade name P
o1y BD R45HT, ARCOChemic
Made by al Co, acrylonitrile content 0%)
1,000 parts of inphorone diisocyanate and 186 parts of inphorone diisocyanate were charged and reacted for 6 hours at 130°C under a nitrogen stream to produce a prepolymer with a free isocyanate content of 2.88%, and then 815 parts of methyl ethyl ketone was added to form a homogeneous solution of urethane prepolymer. . Next, 2001 parts of the urethane prepolymer solution was added to a mixture consisting of 58.3 parts of isophoronediamine, 16.3 parts of di-n-butylamine, 1146 parts of methyl ethyl ketone, and 980 parts of isopropyl alcohol, and then reacted at 50°C for 3 hours. Ta. The thus obtained polyurethane resin solution (hereinafter referred to as resin solution) had a resin solid content concentration of 30% and a viscosity of 980 cP/25°C. Further, the number average molecular layer of the polyurethane resin was 22,000. Production Example 5 1000 parts of poly(1,2-propylene adipate) glycol having a hydroxyl value of 56 and 222 parts of isophorone diisocyanate were placed in a round bottom flask equipped with a stirrer, a thermometer and a nitrogen gas inlet tube, and the mixture was heated at 100°C under a nitrogen stream. After reacting for 6 hours to produce a prepolymer containing 1i3.34% of free isocyanate, 815 parts of methyl ethyl ketone was added to form a homogeneous solution of urethane prepolymer. Then,
2037 parts of the urethane prepolymer solution was added to a mixture consisting of 77.0 parts of isophoronediamine, 8.4 parts of di-n-butylamine, 1219 parts of methyl ethyl ketone, and 1017 parts of isopropyl alcohol, and then heated at 50°C.
The mixture was allowed to react for 3 hours. The thus obtained polyurethane resin solution (hereinafter referred to as resin solution E) had a resin solid content concentration of 30% and a viscosity of 620 cP/25°C. In addition, the number average molecular weight of polyurethane resin is 28,000
Met. Examples 1 to 3 and Comparative Examples 1 to 3 Titanium white (rutile type) 30 parts Production example 1
- Polyurethane resin solution obtained in step 5 50 parts toluene
A white printing ink was prepared by kneading a mixture of 10 parts of isopropyl alcohol in a paint shaker. To 100 parts of the resulting mixture, 35 parts of toluene and 15 parts of isopropyl alcohol were added to adjust the viscosity, and five white printing inks as shown in Table 1 were prepared. The white printing ink of Comparative Example 3 was obtained by adding 2 parts of isophorone diisocyanate to the ink obtained in Comparative Example 2 to obtain a two-component printing ink. The resulting six white printing inks were printed to a thickness of 15 μm using a simple gravure printing machine equipped with a gravure plate with a plate depth of 30 μm.
The discharge treated surface of the corona discharge treated nylon film (NY) and the 11 μm thick polyethylene terephthalate (PE)
T) was printed on one side and dried at 40 to 50°C to obtain a printed film. Then, on the printing surface of the obtained printing film, a solid content of 7%
An isocyanate-based anchor coating agent was applied and dried using a simple gravure printing machine equipped with a gravure plate having a plate depth of 15 μm. Next, using a simple extrusion laminator,
A laminate film was obtained by extrusion laminating polyethylene of 20 μm and 40 μm on the coated surface. The laminate strength (adhesive strength) and boilability at 90° C. of the laminate film thus obtained were evaluated. The evaluation results are shown in Table 1. ■ Room
Heat-seal the laminated film with the polyethylene film side inside, fill the resulting bag with a mixture of salad oil/vinegar/water = 1/1/1 (weight ratio), and heat it at 90°C for 30 minutes. Changes in appearance after boiling were observed. 0---------No abnormality with the film. Δ------A small portion of the film is delaminated or a small amount of blistering occurs. X---------A part of the film is delaminated or blistering occurs. ■- After boiling the laminate film filled with a mixture of salad/vinegar/water = 1/1/1 (weight ratio) at 90°C for 30 minutes, the laminate film was cut into 15 mm width pieces and peeled off. T-peel strength (unit:
g/15mm) was measured and compared with the strength before boiling.

【Effect of the invention】

The one-component printing ink using the printing ink binder of the present invention exhibits excellent adhesion and boiling resistance to various plastic films such as polyester, nylon film, polyethylene, and polypropylene as printing substrates. Deepen.

Claims (1)

[Claims] 1. Consists of 10-30% by weight of acrylonitrile and 90-70% by weight of butadiene, and has a number average molecular weight of 70
A binder for printing ink, comprising polyurethane containing 20 to 90% by weight of butadiene/acrylonitrile copolymer units of 0 to 10,000 in the resin solid content.