JPS6028663B2 - Method for manufacturing laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a laminate in which a base material of a plastic film or other molded product is subjected to metal vacuum deposition processing.

Traditionally, metals such as aluminum or silver are vacuum-deposited on plastic substrates under a reduced pressure of 10-4 to -5 Hg to create products with beautiful metal options that can be used for electrical parts, decoration, or packaging. etc. are widely used.

In this case, the adhesion at the interface between the plastic and the metal vapor deposition film varies considerably depending on the type of plastic.
In particular, it is difficult to form an aggressively deposited film on polyolefins with low polarity, and, common to all plastics, the deposited film that is formed loses its adhesion properties significantly due to deterioration over time. The spread of laminates using gold-deposited films has been hindered. Conventionally, attempts have been made to apply cleaning treatments, sandplast methods, or reactive primers to improve this adhesiveness. However, the practical application suitability is poor, the selection of plastics is limited to medium and medium, and in the case of primer treatment, there is a limit to the time available for evaporation after primer treatment, etc. , this solution was strongly desired. In addition, if metal vapor deposition is applied after gravure or flexo printing on a plastic substrate, the metal may enter the printing ink and cause discoloration of the ink, so it is necessary to apply an overcoat agent to the ink area. Since this requires a complicated manufacturing method for the laminate, the lack of adhesive strength between the layers has been a major problem. In addition, when printing, When the plastic base material is polyolefin, the adhesion of printing ink tends to be poor, and printing is performed after applying a primer for printing ink to the plastic substrate, or the adhesion is promoted during printing ink. When applying a primer, there are many steps such as primer application → printing → overcoat agent application. As a result of intensive research into improving adhesive strength and simplifying the production of laminates, the present invention was developed by applying an organic solvent solution (hereinafter referred to as overcoat varnish) using a one-component moisture-curable polyurethane resin, and then metal vapor deposition. It was discovered that through processing, it is possible to obtain a highly adhesive metal vapor deposited film that is resistant to changes over time and has strong adhesion even when the plastic base material is polyolefin.

The plastic base material according to the present invention is a plastic film or other plastic molded product,
Polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyester, ny.

These are films made of carbon, cellophane, polycarbonate, etc., or other molded products. It is preferable to apply the present invention to a polypropylene film as a plastic substrate, for which it has been difficult to obtain sufficient adhesive strength using conventional methods. When printing on plastic substrates, gravure and flexographic methods are usually used. When performing printing, it is possible to apply a primer for printing to the plastic substrate, but this increases the number of steps. The overcoat varnish according to the present invention is an organic solvent solution containing an overnight moisture-curable polyurethane resin. Overnight moisture-curing polyurethane resins usually contain 1 to 10% isocyanate groups.
(NCO equivalent/total molecular weight) is the remaining polyurethane resin. That is, tolylene diisocyanate (TDI),
Methylcyclohexane diisocyanate, 4,4-diphenylmethane diisocyanate (MDI), 4,4-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate (HMDI), xylylene diisocyanate (XDI), phenylene diisocyanate, naphthylene diisocyanate, toluidine diisocyanate, Isocyanate compounds such as isophorone diisocyanate and triphenylmethane triisocyanate, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,4-butanediol, 1,3-hexanediol, glycerin, polyethylene glycol, trimethylolpropane, polyoxy By reacting with polyhydroxyl compounds such as propylene glycol, bentaerythritol, polypropylene glycol, polybutadiene, ethyl hydroxyacrylate, sorbitol, alkyd resin, polyether polyol, polyester polyol, acrylic polyol, and castor oil derivatives, isocyanate groups are created in the molecule. 1
It is a polyurethane resin with about 10% remaining. In addition,
A one-component polyurethane resin without residual isocyanate groups, such as an oil-modified one-component polyurethane resin, has poor adhesion, and a two-component polyurethane resin has problems such as blocking properties and pot life, and is therefore undesirable.

One-component moisture-curable polyurethane resin can provide sufficient adhesion after curing even when used alone, but in actual in-line methods, that is, when applying immediately after printing, etc., the speed of printing, etc. must be slowed down. The coating is amazing.

Therefore, it is preferable to use a one-component moisture-curable polyurethane resin together with a resin that has relatively low reactivity and does not rapidly gel. Resins used in combination include vinyl chloride resin,
Examples include vinyl chloride/vinyl acetate copolymer resin, acrylic resin, polyurethane resin, and chlorinated polypropylene. As the organic solvent, volatile solvents used for dissolving resins can be used, such as ketone series, ester series, hydrocarbon series, etc., and one or more of these are used.

Note that alcohol and water cannot be used because they react with the one-component moisture-curable polyurethane resin. Moreover, various additives can also be added to the overcoat varnish in the present invention.

The general composition of the overcoat varnish according to the present invention is one-component moisture-curable polyurethane resin, 2 to 25 parts by weight of resin used in combination, and 0 to 2 parts by weight of organic solvent.
55 to 9 parts by weight,
If the plastic base material is 0.01 to 0.0 on its printing surface.
Apply about 5 ta'.

The overcoat varnish can be applied not only to the entire surface of the plastic substrate or to the printed plastic substrate, but also to be applied partially, such as only on the printing ink. The overcoat varnish is applied by any appropriate means such as spraying, printing, dipping, etc., and is then air-dried or forced-dried.
Immediately after applying the overcoat varnish or after several days, the next metal vapor deposition process is performed. The metal vapor deposition process according to the present invention is a commonly used method.
This is carried out by heating a metal such as silver to a temperature above the melting point of the metal under a reduced pressure of about 10-4 to -5 skin Hg. The laminate obtained according to the present invention may be further subjected to molten polyethylene lamination (commonly known as extrusion lamination) or dry lamination using a polyurethane resin adhesive using polyethyleneimine, organic titanate, isocyanate compound, etc. as necessary. By straining, it can be used for packaging purposes.

That is, the laminate obtained by the present invention includes polyethylene and is automatically made into bags by heat-sealing the laminate made of oriented polypropylene. Next, the features of the present invention will be described.

'1} Regardless of the plastic base material and printing ink,
Metal vapor-deposited films can be firmly bonded, and sufficient adhesive strength can be obtained even for polypropylene, which has been considered particularly difficult to bond.

Furthermore, there is almost no deterioration over time. '2} Because the overcoat varnish uses a one-component moisture-curable polyurethane resin, unlike two-component polyurethane resins, there are no problems such as flocking or pot life, and the application speed can be maintained on a practical line. His aptitude is also excellent. [3' When printing on a plastic substrate, the overcoat varnish of the present invention prevents metal from entering the printing ink due to metal vapor deposition.

(4l) In cases where polyethylene or unstretched polypropylene is laminated to a plastic base material or a laminate made of a printed plastic base material and metal vapor-deposited using the conventional method, and the bag is automatically made by heat-sealing, the heat-sealed part However, due to strain, the adhesive strength (laminate strength) suddenly decreased, leading to rupture.

However, when laminated using the laminate obtained according to the present invention, the heat resistance is improved, and the deterioration of the adhesive strength of the heat-sealed portion is not only reduced but also tends to be improved. Next, reference examples and examples will be shown.

However, "parts" and "%" in Reference Examples and Examples are parts by weight and % by weight, respectively. Reference example 1 ■ Overcoat varnish composition - Liquid-curing urethane resin (Takenate M402 manufactured by Takeda Pharmaceutical Co., Ltd.) 1 Ikari Kuni'o}
Any of the following resins (1 to 9) 3 parts Methyl ethyl ketone notolene (50/50) 87 parts <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 17LL manufactured by Sanyo Kokusaku Pulse Co., Ltd.)
B) 4 Vinylidene chloride-acrylic copolymer (Aron CXS-2 manufactured by Toagosei Co., Ltd.) 5 Vinyl chloride/vinyl acetate copolymer (Denka Vinyl 1000A manufactured by Denki Kagaku Kogyo Co., Ltd.) 6
Polyvinyl butyl ether (Raloflex MP-45 manufactured by Vadeitsch) 7 Acrylic resin (Dyanal BR-60 manufactured by Mitsubishi Rayon Co.) 8 Polyvinyl butyl ether (half second butyrate manufactured by Eastman Chemical Co.) 9 Polyurethane resin (manufactured by Dainippon Ink & Chemicals Co., Ltd.) Burnock M5201)'i Mix in a mixer for one day and dissolve to prepare overcoat varnish.

'B) Adjustment of printing ink Adjustment of white ink (I) Titanium White 3 Ikarito'
0} Nitrocellulose SSI'4 varnish (manufactured by Asahi Kasei Corporation, non-volatile content 23.5% ethyl acetate varnish) 38 parts day Maleic acid resin 4 parts W Citric acid plasticizer (manufactured by Pfizer Inc., USA) 5 parts Ethyl acetate
2 Moribe's mixture is milled in a ball mill to prepare white printing ink.

Adjustment of red ink Brilliant Carmine Sasa S (Soluble Azo Pigment manufactured by Toyo Ink Co., Ltd.) 1 Boto [Ro Nitro Cell.

-SSI/4 varnish 6 parts 1 maleic acid resin 2 parts 0 citric acid solubilizer
Pentapartial ethyl acetate
Adjust the red color using the same procedure as for white ink using 2 parts of the mixture. The white ink, red ink and varnish obtained above were applied to the first unit and second unit using a multicolor gravure rotary printing machine, and the red and white inks were applied to a 30 mg grapier plate at an oven temperature of 40 to 50°C. Then, the third unit prints 30 French gravure plates,
A corona discharge treated biaxially oriented polypropylene film (OPP) printed with red ink and white ink was coated with an in-line method under conditions of applying warm air at an oven temperature of 7 to ○.
Overcoast varnish was applied at a printing speed of 0 mm/min.

Table 1 shows the results of a peel test on the obtained printed film using cellophane tape. As a comparative example, a comparison will be made with a case in which a one-component moisture-curable urethane resin is not included.

In other words, the resin (1
~9) is an organic solvent solution. Table 1 (Note) Apply cellophane tape to the red/white/overcoat varnish area and OPP/overcoat varnish area, peel off rapidly at a 6-point angle, transfer to the cellophane tape surface, and peel off. Adhesive strength is expressed in proportions: 1: full-surface peeling, 2: 70 shot peeling, 3:
50: multiple peeling, 4: 20 purple peeling, 5: no peeling o Reference example 2 Preparation of overcoat varnish} Polyurethane resins (HMDI and poly( oxypropyresoether) (consisting of polyol)
4 parts {o- Thermoplastic polyester resin (Vylon 200) 4 parts Methyl ethyl ketone/toluene (60/40) 85-9 parts Butyl acetate and xylene 7-2 parts Obtained overcoat varnish and in Reference Example 1 The obtained ink was printed in the same manner as in Reference Example 1, and the obtained printed film was subjected to a peel test using cellophane tape. The results are shown in Table 2.

Table - Year 2 8 Liquid stability means when left unattended ○: Almost no change after 1 week or more △: Cloudy in one week ×: 'Cloudy even for 1 day are shown respectively.

Reference Examples 1 and 2 show that the overcoat varnish containing a one-component moisture-curable polyurethane resin has excellent adhesiveness and liquid stability, and is highly practical.

Example 1 Adjustment of overcoat varnish
02) 5 parts vinyl chloride/vinyl acetate copolymer (electrified vinyl 100 skin T3
) and acrylic resin (Dyanal BR60 manufactured by Mitsubishi Rayon Co., Ltd.) 18 parts N Methyl ketone notluene (60/40) 77 parts The obtained overcoat varnish and the same printing ink as in Example 1 were used. After gravure printing was performed on a corona discharge treated biaxially stretched polypropylene film (Torayuan 2535 #20 manufactured by Toray Industries, Inc.) under the following conditions, aluminum vacuum evaporation processing was performed, and polyethyleneimine and polyethyleneimine were added as anchor coating agents, respectively.
Table 3 shows the results of polyethylene extrusion lamination using organic titanate and isocyanate compounds (Coronate L manufactured by Nippon Polyurethane Industries, Ltd.) and measuring the lamination strength.

The strength values are expressed in grams (grams) of the force required to peel off the base material and the laminate film in 15 samples. The results are also shown. Table-3 Lamination strength (
Note) Lamination: 30〃Low pressure polyethylene Lamination strength measurement: Instron speed 30 final product 90T type peeling This test significantly improved the adhesion between the printing ink and the printing substrate, and the aluminum It is recognized that the adhesion between the adhesion layer and 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 Laminate strength after heat sealing of extension laminate (Unit: 1/15 ribs) (
Note) Heat tunnel conditions: 130℃, 301bs/inc
h・lsec. Example 2 A two-component reactive polyurethane adhesive (BHS3955/395 group manufactured by Toyo Ink Mfg. Co., Ltd. = 100/3) was applied to aluminum vapor-deposited printed matter similar to Example 1.
), and the results of measuring the lamination strength are shown in Table 5.

Table 5 Lamination strength (unit: 1/15 ribs) Comparative example shows the laminate strength when no overcoat varnish is used.

This test showed that the metal vacuum-deposited laminate according to the present invention had excellent vapor deposition effect, metal selectivity, adhesion to the ink area, adhesion of the vapor-deposited film, etc., and no decrease in laminate strength was observed. However, both the ink/aluminum part and the plain part,
No lifting occurred between the film base material (polypropylene film) and the laminate film (polyethylene). For comparison, a similar laminated product printed and vapor-deposited with the same ink as in Example 1 without using the overcoat varnish of the present invention had poor vapor-deposition effect on the ink area.
The laminate strength is extremely reduced, the film base material and polyethylene float, and the bag becomes useless.

By using the overcoat varnish of the present invention, suitability for metal vacuum deposition processing was improved, and stable laminate strength could be obtained.

Claims (1)

[Scope of Claims] 1. After applying an organic solvent solution containing a moisture-curable polyurethane resin to a plastic substrate or printing on a plastic substrate overnight, metal evaporation processing is performed, and if necessary, A method for manufacturing a laminate, characterized by performing lamination processing. 2. The method for producing a laminate according to claim 1, which uses an organic solvent solution containing a one-component moisture-curable polyurethane resin and a non-gelling resin. 3. The method for producing a laminate according to claim 1 or 2, wherein the plastic base material is a polypropylene film.