JPS6040993B2 - Printed matter manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing printed matter by gravure or flexography, and relates to a printing method using nitrocellulose as the main binder, which is excellent in high-speed printing suitability, printing effect, organic solvent releasability, etc. and is relatively inexpensive. When printing ink on polypropylene film, sufficient adhesion is achieved by applying a primer of an organic solvent solution of a one-component moisture-curable polyurethane resin and a resin that does not react with the polyurethane resin or gel. The present invention relates to a method for producing printed matter that can be made to have.

There is a wide selection of resins that can be applied to gravure printing ink, and it has the advantage of being able to print on almost any film. It has achieved remarkable growth in the light packaging field.

On the other hand, a large variety of printing inks have been researched depending on the type of printing material and the purpose of use, and the large variety and complexity of these inks have made it difficult not only for ink manufacturers but also for the printing industry to manage the increasing inventory of hazardous materials. It was a real situation because I was worried about it. The situation in flexography printing was almost similar.
In other words, the formulation of the printing ink had to be changed depending on the printing material, taking into account the adhesion of the printing ink to the printing material. In general, printing inks containing nitrocellulose as the main binder are excellent in high-speed printing suitability, organic solvent releasability, and economic efficiency, but they are only used for special formulations, such as paper or plain cellophane. First, it does not have sufficient adhesive strength for other plastic films.

Also, due to its lack of water resistance, it usually lacks suitability for boiling. In order to improve the above problems, we use special formulations as printing ink on the surface of various substrates.
There is a need for a primer that enables strong adhesion using an ink containing nitrocellulose as the main binder.

Furthermore, when laminating polyethylene, polypropylene, etc. to printed materials, etc., a printing primer is required that does not affect the laminate, that is, does not reduce the strength of the laminate due to a single layer of primer. Furthermore, there has been a need for a method for producing printed matter that can deal with the phenomenon that the lamination strength decreases when heat sealing, boiling, or other processing is performed after lamination. Moreover, it is desirable to have a method for producing printed matter that is suitable for high-speed printing of gravure or flexography printing, has excellent printing effects, and is economical as well. The present inventors previously proposed a method for obtaining printed matter of various films using a primer of an organic solvent solution containing a cyclone coupling agent and a resin (Japanese Unexamined Patent Application Publication No. 51-111).
No. 7807), but upon further study, they discovered that a primer using a specific polyurethane resin is extremely excellent as a primer for polypropylene films and nitrocellulose printing inks.

In other words, a primer consisting of an organic solvent solution of a one-component moisture-curing polyurethane resin and a resin that does not react or gel with the polypropylene film is applied to a polypropylene film, and then nitrocellulose is used as the main binder to produce printed matter. This is a manufacturing method for printed matter, which further includes laminating and heat-sealing or boiling after laminating. The film to be subjected to gravure or flexographic printing is a corona discharge treated biaxial polypropylene film (abbreviated as OPP). The present invention can also be applied to polypropylene films other than OPP. The one-component moisture-curable polyurethane resin according to the present invention is a polyurethane resin in which normally 1 to 7% (NCO equivalent/total molecular weight) of NCO groups remain.

Isocyanates such as tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HMDI), and xylylene diisocyanate (XDI), and polyfunctional materials such as various diols and triols. It is a polyurethane resin that is reacted with a natural hydroxy compound and has 1 to 7% of NCO groups remaining in the molecule.
It is a polyurethane resin commercially available under trade names such as 5M, M80-5, and X (manufactured by Mitsui Tosho Co., Ltd.). It is applied to polypropylene film and cured by moisture in the air. In addition, one-component oil-modified polyurethane resin with no remaining NCO groups,
One-component block polyurethane resins have poor adhesion, while catalyst-type and two-component polyurethane resins have poor blocking properties.
It has problems with pot life and is not suitable for use in the present invention. Even when one-component moisture-curable polyurethane resin is used alone, sufficient adhesiveness can be obtained after curing, and there is no problem in practical use. Poor adhesion (initial ripening) and unfavorable in terms of print management.

Therefore, a resin that has good wettability with nitrocellulose and does not gel with a polyurethane resin is used in combination. Examples of resins used in combination include vinyl chloride derivative resins, acrylic resins, vinyl chloride/vinyl acetate copolymer resins, and chlorinated ethylene/pinyl acetate copolymer resins. Further, as the organic solvent, volatile solvents normally used for dissolving resins can be used, such as ketones, esters, hydrocarbons, or mixtures thereof.

however. Alcohols such as methyl alcohol and inpropyl alcohol and water cannot be used because they react with isocyanate groups. The general composition of the primer according to the present invention is one-component moisture-curable urethane resin, 2 to 8 parts by weight, combined resin, 0.5 to 5 parts, and organic solvent.
The amount of urethane resin to be applied to the surface to be treated is 0.1 to 0.05 m/m.

Next, the features of the present invention will be described. {1} - A primer consisting of a liquid moisture-curable urethane resin (1 to 7% of residual NCO groups) and an organic solvent with a resin that does not react with it to form a gel, for gravure or flexographic printing. polyp.

By using pyrene film, it strengthens the adhesion of commonly formulated printing inks with nitrocellulose as the main binder to the printing substrate, reducing the number of types of ink or paint depending on the type of printing material or the different uses. In addition to coating the printed surface with a resin film using another anchor coating agent, the adhesion between the printing material and the ink and another anchor coating layer is strong and durable. Strong prints or laminates thereof can be obtained. '2' Despite the fact that printing inks with nitrocellulose as the main binder generally have excellent high-speed printing suitability, organic solvent removal properties, and economic efficiency,
Except for special formulations, it is mainly used for paper, paper, and plain cellophane, and does not have sufficient adhesive strength for other plastic films.

Also, due to its lack of water resistance, it usually lacks suitability for boiling. However, the coated primer layer not only has sufficient adhesion to the primer according to the present invention but also has sufficient water resistance and heat resistance, so that the nitrocell is protected by this.

Printed matter using ink containing 100% polyester as the main binder has sufficient suitability for boiling. {3' Printed matter based on this manufacturing method can be used for molten polyethylene lamination (commonly known as extrusion lamination) using polyethyleneimine, organic titanate, isocyanate, etc. as an anchor coating agent, or dry lamination using polyurethane adhesive. Sufficient lamination strength can be obtained in both the ink part and the primer part where no ink is present.

{4'Those laminated with printed matter and polyethylene or unstretched polypropylene in this way are generally used primarily for food packaging after automatic bag making; When heat-sealing, the laminate strength sharply decreases due to distortion due to changes in that part, which tends to lead to rupture.

However, the heat resistance of the laminate produced by the method of manufacturing this printed matter is improved, and the deterioration of the laminate strength in the heat-sealed portion is not only slight but also tends to be improved. '5'
Dry lamination using an adhesive is mainly used for purposes such as boil sterilization after filling.

This is intended for long-term preservation of the contents (food), but the dry laminated printed matter according to the present invention has improved heat resistance, water resistance, and solvent resistance, so it can be used for boiling processing.

In the past, it has been difficult to obtain printed materials that have the adhesion properties of printing inks, exhibit strong adhesion during lamination, and are also heat resistant. Also, technically superior printed matter can be obtained. (2) Printed matter obtained by this manufacturing method tends to have a reduced amount of organic residual solvent compared to printed matter using a special ink formulated according to the printing material.

Next, examples will be shown.

However, parts in the examples are parts by weight. Example 1 Primer composition - Liquid moisture curing urethane resin 1 Foundation part (
Takenate M402)'o, manufactured by Takeda Pharmaceutical Co., Ltd. 3 parts of the following resins (1 to 9) (1 to 9) 87 parts of methyl ethyl ketone/toluene (60/40) <Resin> 1 Thermoplastic polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) ) 2 Chlorinated ethylene/vinyl acetate copolymer (Super Chron LLB, manufactured by Sanyo Kokusaku Pulp Co., Ltd.) 3 Chlorinated polypropylene (Hardren 17L, manufactured by Sanyo Kokusaku Pulp Co., Ltd.)
LB) 4 Vinylidene chloride-acrylic copolymer (Lon CXS-2, manufactured by Toagosei Co., Ltd.) 5 Vinyl chloride/vinyl acetate copolymer (Denka Pinil 100 Hada T3) 6 Polyvinyl butyl ether (Laloflex M Yenichi, manufactured by Badish Co., Ltd.) 4
5) 7 Acrylic resin (Dianal B manufactured by Toei Kasei Co., Ltd.)
R-60) 8 Polyvinyl butyl ether (half second butyrate manufactured by Koostman) 9 Polyurethane resin (Barnok M5201 manufactured by Dainippon Ink)
Mix and dissolve ~1 in a mixer to prepare a primer.

Song Adjustment of printing ink Adjustment of white ink Titanium white 3 no Kaku'0
) Nitrocellulose SSI'4 varnish Isobe (non-volatile 23.5% ethyl acetate varnish manufactured by Asahi Kasei Corporation) Ester gum 4 parts 0 citric acid plasticizer (manufactured by Pfizer, USA) 5 parts {vs. ethyl acetate
A mixture of 23 parts (a) and 23 parts is milled in a ball mill to prepare a white printing ink.

Adjustment of red ink) Brilliant Carmine Washing S (Soluble azo additive manufactured by Toyo Ink Co., Ltd.) 1 Ikari Kuni (〇1 Nitrocell.

-SSI/4 varnish 6 anchor part ester gum
Part 2 0 Phenic acid plasticizer
5 parts■ Ethyl acetate
A red ink is prepared by using a mixture of 23 parts of 1 to 1 in the same manner as the white ink.

The primer and white and red inks obtained above were coated with the primer using a multicolor gravure rotary printing machine on a 20r gravure plate in the first unit at an oven temperature of 70 oo, and then in the second and third units. Red and white inks were printed in-line at a printing speed of 120 m/side on a corona discharge treated biaxially oriented polypropylene film (OPP) using a 30 mg Grapia plate and applying hot air at an oven temperature of 40 to 50°C.

Table 1 shows the results of a peel test on the obtained printed film using cellophane tape. As a comparative example, a case in which no one-component moisture-curable urethane resin is included will be compared.

Table I (Note) Apply cello tape to the red/white ink printing area.
Sudden peeling at 600 angle ``Transfer to cellophane tape surface'' Adhesive strength is indicated when peeling 1: Complete peeling, 2: 70% peeling, 3: 50 multiple peels, 4: 20% peeling, 5: No peeling Show each.

Example 2 Preparation of primer (a) Polyurethane resins with different residual NCO group contents shown in Table 2 (composed of HMDI and poly(oxypropylene ether) polyol) 4 parts'o) Thermoplastic polyester resin (Toyobo Byron 200) )
Part 4 Shiichi M Old K Notluene (60/40>
85-9 anchor part〇 Other solvents
7 to 2 parts (inpropyl acetate, butyl acetate, xylester) The obtained primer and the ink obtained in Example 1 were printed in the same manner as in Example 1, and the obtained printed film was covered with cellophane tape. The results of the peel test are shown in Table 2.

2 (Note) Liquid stability refers to when maintained. ○: Almost no change after 1 week or more △: Cloudy in one week ×: Cloudy even for one day are shown respectively.

Example 3 Adjustment of primer {ee-liquid temperature curable urethane resin 1 rim part (
Takenate M402) [o} Vinyl chloride/vinyl acetate copolymer 2 parts (electrified vinyl 100 skin T3) Shiichi M
Old K/toluene (60'40) 88 parts Using the obtained primer and the same printing ink as in Example 1, a corona discharge treated two-mari stretched polypropylene film (Torayuan 2535 #20, manufactured by Toray Industries, Ltd.) was prepared under the same conditions. After gravure printing, *as an anchor coating agent,
Table 2 shows the results of polyethylene extrusion lamination using polyethyleneimine, organic titanate, and isocyanate, and measuring the lamination strength.

The strength value is expressed in grams as the force required to peel off the base material and the laminate film in 15 samples.Table 3 also shows the results of a comparative example in which no primer was used. Table←3 Extrusion laminate strength (Note) Lamination: 30〃Low pressure polyethylene laminate strength measurement: Instron speed 30 S/skin 90T type peeling This test significantly improves the adhesion between printing ink and printing substrate However, it is recognized that the adhesive strength with the anchor coating layer used for lamination is also excellent.

Next, Table 4 shows the measurement results of the laminate strength after heat-sealing the same extrusion laminate.

Table 4 Lamination strength after heat sealing of extrusion laminate (Note) Heat sealing conditions: 130°C 301 bs/inch lsec Example 3 A two-component reactive polyurethane adhesive was applied to the same printed matter as in Example 2. agent (Adocoat 30 manufactured by Morton Chemical Company)
Table 5 shows the results of dry lamination using 1A/Adocoat 350A) and measurement of lamination strength.
Shown below.

Comparative examples show laminate strength without the use of primer.

Next, the results of heat-sealing or boiling the dry lamination of the same machine are shown in Tables 6 and 7, respectively.

Table-6 (Note) Heat sealing conditions: 140o0 301bs/i
nchISeC Table-7 Lamination strength after boiling (Note) Boiling conditions: 95°C 30 minutes Oil Material: Millsug Warm water 3240 parts Foleic acid 1.5 parts CMC 40 parts Water 385 parts Salad oil 105 parts This test revealed that the present invention The printed matter has excellent lamination strength by dry lamination, and no decrease in lamination strength is observed after heat sealing and boiling treatment, but rather tends to improve.

The appearance of the bag after the boiling process is good, and even if the bag is forcibly soaked, no lifting occurs between the film base material (polypropylene film) and the laminate film (polyethylene) in both the ink and plain areas. It's durable enough. For comparison, when the same ink as in Example 1 was printed without using the primer of the present invention, and the laminate of the same machine was boiled, there was no problem in the plain area, but the laminate after the boiling process in the ink area was The strength is extremely reduced, the film base material and polyethylene float, and the bag becomes useless.

Claims (1)

[Claims] 1. Amount of isocyanate remaining in polypropylene film 1
A primer of ~7% one-component moisture-curable polyurethane resin and an organic solvent solution of the polyurethane resin and a non-gelling resin is applied, and then gravure is applied using a printing ink containing nitrocellulose as the main binder. Or a method for producing printed matter characterized by flexographic printing. 2 Amount of isocyanate remaining in polypropylene film 1
A primer of ~7% one-component moisture-curable polyurethane resin and an organic solvent solution of the polyurethane resin and a non-gelling resin is applied, and then gravure is applied using a printing ink containing nitrocellulose as the main binder. Or a method for producing printed matter, which includes flexo printing and lamination, or heat sealing or boiling after lamination.