JPH02140275A - Printing ink - Google Patents

Abstract

PURPOSE:To obtain novel printing ink useful as an ink for backing printing and having excellent gloss, etc.. by using polyurethane-polyurea resin resulted from reaction of diols of high-molecular weight, specific diisocyanates and specific chain extender. CONSTITUTION:For instance, preferably (A) diols having 300-5000 molecular weight (e.g., polyethylene glycol) is reacted with (B) diisocyanates containing 1,3-bis(alpha,alpha-dimethylisocyanate methyl)benzene expressed by the formula as essential component and isocyanate prepolymer is obtained. Then, said prepolymer is reacted with (C) chain extender composed of diamines or said diamines and diols having about 62-250 molecular weight (e.g., ethylenediamine) to afford a polyurethane-polyurea resin. Next, said resin is mixed with pigment, solvent and various additive components, etc., and blended in a device such as ball-mill to afford the aimed printing ink.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a new and useful printing ink.

Furthermore, in detail, the present invention comprises using a polyurethane polyurea resin obtained by using specific diols, specific diisocyanates, and diamines as essential raw material components as a pihycryl solid. The invention relates to a useful printing ink that can be coated onto the surface of substrates such as plastics films.

[Conventional technology]

In recent years, plastic films have become popular as packaging materials, and as a result, the demand for printing inks for these plastic films has also increased. ing.

In Japan, special gravure inks are mainly used as printing inks for such purposes, in order to cope with higher printing speeds and to give printed materials more impact and beauty.

Depending on which side of the film the film is printed on, it is classified into ``6 front printing'' and ``back II #)''.

First, for front printing, a general-purpose type that requires gloss is used, and then for back printing, gloss is not required, but it is laminated after printing, and Since there is a need for something strong enough to withstand boiling and retort processing, it can be said that a slightly higher grade type is in response.

Currently, the ink that uses a urethane resin as a vehicle is the most commonly used ink for back printing. A solid material is used.

These urethane urea resins themselves have excellent adhesion to various plastics and films, and if polyisocyanate If is used as a curing agent for the urethane urea resins, they can withstand dill retort treatment. Therefore, demand for the resin continues to increase.

By the way, after printing with this back printing ink, the printed film is usually laminated with another film and provided in the form of a so-called multilayer film.

Therefore, the printing ink used in this case has sufficient strength when peeling such laminates (called laminate strength), and even after boiling and retort processing, this laminate strength can be maintained. It is desirable that the

However, when increasing the molecular weight of the urethane urea resin itself as a vehicle as a means to improve lamination strength, dill retort resistance, etc., printability may decrease or the ink viscosity may be too high. Problems such as scratches may occur.

In the end, an ink that maintains the printability inherent to urethane urea resin and has sufficient lamination strength, boiling and retort resistance, and other properties particularly required for back printing inks has not yet been obtained. The current situation is that they are used in a way that sacrifices printability on the one hand and properties such as lamination strength and boil/retort resistance on the other.

[Problem to be solved by the invention]

However, in view of the various problems in the prior art as described above, the present inventors have attempted to improve the laminate strength and yJ resistance.
r) As a result of intensive research with the aim of obtaining a printing ink with excellent retortability and a well-balanced performance including printability, we found that 1,3-bis(α After discovering that a printing ink whose vehicle solid is a polyurethane urea resin obtained using a specific product called . He has completed his invention.

[Means to solve the problem]

That is, the present invention uses, as essential vehicle solid components, a diol group having a molecular weight of 300 to 5,000, and 1,3-bis(α,α-tumethylisocyanatomethyl)benzene (B ), and a chain extender (Q) consisting of diamines (c-1), or the diisocyanates (B), which require diamines (c-1).
and diols (c-
The present invention aims to provide a new and useful printing ink which uses a polyurethane polyurea resin obtained by reacting a chain extender (2) with a chain extender (Q).

Here, first, the diols (A) used in preparing the above polyurethane polyurea resin are:
This refers to compounds with a molecular weight in the range of 300 to 5,000, but the diols have a molecular weight in a relatively different range from the diols (c-2) used as chain extenders. Therefore, the diols (A) are also called high molecular weight diols, and the other diol (c-2) is sometimes called low molecular weight diols.

Typical examples of such high molecular weight sols include polyalkylene glycols such as polyethylene glycol or polypropylene glycol, polyoxyethylene glycol, polyoxyethylene glycol, polyoxyethylene propylene glycol, or polyoxytetramethylene glycol. Various polyether type diols such as polyoxyalkylene glycols; ethylene oxide of bisphenol A;
Alkylene oxide adducts of propylene oxide or ethylene propylene oxide; dicarboxylic acids (anhydrides) such as succinic acid, adipic acid, glutaric acid, phthalic acid (anhydride), isophthalic acid, maleic acid or fumaric acid, and ethylene glycol, diethylene glycol , phlopylene gellicol (1,3-propanediol)
, 1,4-butanediol, 1,3-butanediol,
Esterification with diols such as 1,6 hexanediol, 1,9-nonanediol, neopentyl glycol, 3-methyl-1,5-bentanediol, 3,5,5-trimethyl-bentanediol or hydrogenated bisphenol A Condensates obtained by the reaction, polyester diols such as cabrolactone, valerolactone, or methylvalerolactone polymers obtained by using the various diols listed above as initiators, polycarbonate diols, or polybutadiene diols. etc.

The molecular weight of these high molecular weight diols (N) is suitably within the aforementioned range of 300 to 5,000, preferably within the range of 500 to 3,000.

When it is less than 300, the printing suitability and coating suitability of the obtained polyurethane polyurea resin tend to be poor, while when it exceeds 5,000, the obtained polyurethane polyurea resin itself tends to have poor blocking properties. Both are undesirable as they tend to cause

Next, as the diisocyanates (B), first,
1,3-bis(
While α,α-trimethylisocyanate methyl)benzene (hereinafter abbreviated as BDMIB) is essential, aromatic isocyanates such as toluene diisocyanate, xylene diisocyanate or diphenylmethane diisocyanate; methylenezoincyanate; Impropylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, 2,2
．． aliphatic diisocyanates such as 4- or 2,4.4-)limethylhexamethylene diisocyanate;
, cycloaliphatic diisocyanates such as 4-cyclohexane diisocyanate, isophorone diisocyanate or 4,4' adicyclohexylmethane soocyanate,
Alternatively, two or more of these various twincyanates can be used in combination with the above BDMIB. In particular, in order to obtain a polyurethane polyurea resin with excellent solubility, printing suitability, coating suitability, etc.
and a cycloaliphatic diisocyanate.

Further, typical examples of the diamines (e-1) used as the chain extender (C) include ethylenediamine, 1,2-nolopylenecyamine, 1.3-7'robylenediamine, 1. Straight chain aliphatic diamines such as 4-butanesoamine or hexamethylene diamine; or isophorone diamine, dicyclohexylmethane-4,4'-
Diamine, cyclohexyl-4,4'
-Diamines, cycloaliphatic diamines such as 1,4-noaminocyclohexane or 1,3-bisaminomethylcyclohexane, water or hydrazine, etc.
Two or more types of these may be used in combination.

Furthermore, the low molecular weight diol (c-2) used as the chain extender (C) has a molecular weight of about 62 to about 2.
50, and representative examples thereof include various diols used in preparing polyester-type diols among those already listed for high molecular weight diols.

To prepare the desired polyurethane polyurea resin using the high molecular weight diols (5), diisocyanates (B), and chain extenders (C) listed above, first,
Polymer jjk diols (8) and diisocyanates (
A high molecular weight diisocyanate compound, that is, an incyanate polymer is obtained by reacting the diisocyanates (B) with the diisocyanates (B) in an excess amount by a conventional method, and then a diamine (C) as a chain extender (C) is reacted with the diisocyanates (B) in a conventional manner. e-1)
Alternatively, there is a method of obtaining the desired resin by reacting diamines (c-1) with low molecular weight diols (c-2). There is also a method of obtaining the desired resin by simultaneously reacting the two, but the former method is safer and
It is also desirable because the reaction can be carried out stably.

The solvent used in preparing such a polyurethane polyurea resin may be any solvent normally used for dissolving urethane resins, and typical examples include aromatic solvents such as benzene, toluene, or xylene. Ester systems such as ethyl acetate, Ml-n-propyl acetate, n-butyl acetate or isobutyl acetate; Alcohol systems such as methanol, ethanol, ingurononol or n-butanol; or acetone, methyl ethyl ketone, methyl Examples include ketones such as inbutyl ketone and cyclohexanone, and these may be used alone or in combination of two or more.

The thus obtained polyurethane polyurea resin is added with pigments, solvents, and, if necessary, various known and commonly used additive components such as antiblocking agents, waxes, and antistatic agents, as well as nitrified cotton or vinyl chloride. A desired printing ink can be obtained by appropriately blending a so-called auxiliary resin such as a vinyl acetate copolymer and using a general ink manufacturing apparatus such as a ball mill, attritor or sand mill.

The printing ink of the present invention thus obtained has excellent gloss and also has the characteristics of urethane inks.

Furthermore, in the present invention, a polyisocyanate curing agent is fully blended as an optional vehicle solid component within a range of 30% or less in terms of solid content weight ratio to the polyurethane polyurea resin, which is an essential vehicle solid component. ,
Since it can also be used as a two-component ink, the utility value of the present invention is further increased.

That is, by using such a two-component ink, the adhesion to the coated film is further improved, and an ink with excellent durability and retortability can be obtained. In addition, the printing ink of the present invention has an advantage in terms of ease of use, since there is little change in viscosity over a long period of time even after the polyincyanate curing agent is blended.

Here, such a polyisocyanate curing agent is a polyisocyanate obtained by an addition reaction between 1 mol of a low molecular weight polyol such as trimethylolpropane and 3 mol of a diisocyanate such as hexamethylene diisocyanate; Typical examples include belet-type polyisocyanates obtained by the reaction of diisocyanates such as methylene diisocyanate with water; and isocyanurate-type polyisocyanates obtained by the polymerization reaction of diisocyanates such as hexamethylene diisocyanate. However, of course, in addition to these, any curing agent that is generally used as a polyisocyanate curing agent can be used.

The printing ink of the present invention can be used to coat the surface of various types of plastic films, etc., and can be used as a special gravure ink for both front and back printing.

〔Example〕

Next, the present invention will be specifically explained with reference to Reference Examples, Examples, and Comparative Examples regarding the sea layer. In the following, all parts and percentages are based on weight unless otherwise specified.

Reference Example 1 (Example of preparation of yj?IJ urethane polyurea resin) Into 21 four-way flasks equipped with a stirrer, thermometer, Thumb funnel, and nitrogen gas introduction tube, a sample having an average molecular weight of 2.00 was placed.
0, a polyester diol obtained by the esterification reaction of 1,4-butanediol and adipic acid.
19 parts were charged, and the temperature was raised to 70°C while stirring.

At the same temperature, 78 parts of BDMIB was added and reacted for 7 hours while flowing nitrogen gas, and then cooled to 40°C while adding 343 parts each of methyl ethyl ketone (MEK) and ethyl acetate, and Dissolved uniformly.

Next, 24 parts of isophorone diamine (IPDA) and 294 parts of gold inpropatool (IPA) were added to the prepolymer thus obtained, and the mixture was reacted at the same temperature of 40°C for 5 hours, so that the nonvolatile content was 30%. A colorless and transparent polyurethane polyurea resin solution having a Gardner viscosity of TU at 25° C. was obtained.

Reference Examples 2 to 9 (same as above) The desired colorless and transparent solutions of various polyurethane polyurea resins were prepared in the same manner as in Reference Example 1, except that the types and amounts of raw materials used were changed as shown in Table 1. I got it.

/ / 30 parts of each of the polyurethane polyurea resins obtained in Examples 1 to 7 and Comparative Examples 1 and 2 Reference Examples 1 to 8 were mixed with 10 parts of MEK, 10 parts of ethyl acetate, and IPA.
After diluting with 5 parts of.

25 parts of titanium oxide was added and kneaded in a ball mill for 24 hours, then [Parnoc DN-950JC polyisocyanate manufactured by Dainippon Ink and Chemicals Co., Ltd.] was added, and then mixed with ethyl acetate until the viscosity was reduced to zero. 1 cup A4
Various printing inks were obtained by diluting the solution to 8 seconds.

As Comparative Example 2, “Laccamite N-164-LJ
30 parts of a solution of 9 parts of [polyamide resin manufactured by Dainippon Ink and Chemicals Co., Ltd.] in 15 parts of toluene and 6 parts of IPA were added to 10 parts of MEK, 10 parts of ethyl acetate, and 5 parts of IPA. After diluting with titanium oxide,
A control printing ink was prepared by adding 100% of Burnock DN-950J and diluting it with ethyl acetate to a viscosity of 18 seconds with Zahnkazzo A4. Using.

Note that the evaluation of various performances was performed in the following manner.

Adhesion: Cellophane tape was attached to the printed area and peeled off rapidly at an angle of 60°, and the evaluation was made based on the rate at which the printed area was peeled off.

◎・・・Complete peeling ○・・・20% peeling △・・・50
% Peeling ×...70% Peeling and clogging: Print normally,
Heat the plate in a dryer until the surface temperature reaches 40℃,
Next, the paper was rotated with a doctor for 30 seconds, printed, and the condition of the printed area was visually determined.

◎...Printed area is clear ○...Slightly unclear △...Kana cine is clear ×...Extremely unclear Lamination strength: 8
A 2-layer film is used as a base material for a sample with a width of m.
The force required to peel it off using "Tensilon" is expressed in grams.

Blocking resistance: Layering the printed surface and film, 3 to 9
After holding at 70° C. for 2 hours at a pressure of /.2, the printed surfaces and the film were peeled off and the condition was visually determined.

◎... Not blocking at all ○... Almost no blocking Δ... Kana blocking ×... Significant blocking, with water/oil mixture inside. After filling and sealing, the presence or absence of "ramid floating" was visually determined after heating at 90°C for 30 minutes for boiling suitability, and at 120°C for 30 minutes for retorting suitability. .

◎...There is no "lamin floating" at all.○...There is some "lamin floating" △...There is pinhole-like "lamin floating" ×...There is "lamin floating" on the entire surface [Invention [Effect] The printing ink of the present invention has excellent lamination strength, boil resistance and retortability, and in addition, it has a well-balanced performance including printability. It is.

Therefore, the printing ink of the present invention is particularly effective as a special gravure ink, not only for front printing but also particularly for back printing.

Agent: Patent Attorney Katsu Takahashi

Claims (1)

[Scope of Claims] 1. Diols (A) having a molecular weight of 300 to 5,000
and the formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [I] Diisocyanates that essentially contain 1,3-bis(α,α-dimethylisocyanatomethyl)benzene (B) and diamines (c-1), or the diamines (c-1) and the molecular weight are about 62
~250 diols (c-2) chain extenders (C
) A printing ink consisting of using a polyurethane polyurea resin obtained by reacting with ) as a vehicle solid.