JPH0587090B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an ink composition and a method for surface treatment of plastic film, and more particularly, it relates to an ink composition and a method for surface treatment of plastic film, and more specifically, it relates to an ink composition and a method for surface treatment of plastic film. In order to make it easy to write on the surface of synthetic paper with ballpoint pens, water-based pens, oil-based pens, pencils, etc., and to give it suitability for stamps, vermilion ink, printability for various printing methods, and suitability for pasting on stamps, labels, etc. The present invention relates to an ink composition and a method of treating a plastic film (hereinafter also referred to as synthetic paper) with the ink composition to impart the above-mentioned various properties to the plastic film. (Prior art and its problems) Traditionally, paper has been used for most of the sheets used for writing and printing, but because paper does not have sufficient strength, water resistance, and storage stability, plastic film and synthetic paper have been used. It has become widely used. In particular, plastics are used in fields where strength, water resistance, preservability, etc. are strongly required, such as materials for postal materials such as various postcards and envelopes, materials for drafting sheets, telephone cards, cash cards, membership cards, etc. Films and sheets are widely used. Plastic films for various uses are required to have surfaces or areas that can be written on with ballpoint pens, water-based pens, oil-based pens, pencils, etc., and are also suitable for stamps, seals, silk screens, and other types of printing. Therefore, it is desirable that the material can be stamped or printed, but in many cases it does not have such suitability for writing, printing, or printing. As a method of imparting various aptitudes as described above, for example, a method of roughening the writing surface is known, but this roughening method does not provide sufficient aptitude. Also, as another method,
As disclosed in Japanese Patent No. 23423, a method is known in which a writing surface is formed using an ink composition containing a resin, a pigment, and a wax. However, the writing surface used in the above method had the following drawbacks and was not sufficiently suitable. (1) When writing with a water-based pen or printing with water-based stamp ink, the ink dries poorly and easily stains hands and other parts. (2) When writing with a pencil, it cannot be erased sufficiently with an eraser, and the writing remains, and when rewritten, it looks very dirty. (3) When pasting stamps, labels, etc. with water-based glue, it takes a long time for them to stick. (4) When using oil-based pens, oil-based stamps, ink ink, etc., the oil resistance is insufficient and the durability against hand oils, alcohol, etc. is insufficient, and smearing and staining are likely to occur. (5) Printability is insufficient for offset printing and silk screen printing. Therefore, an object of the present invention is to provide an ink composition and a method for surface treatment of plastic film, which can form a writing surface, a printing surface, a printing surface, etc., which does not have the above-mentioned drawbacks. (Means for solving the problems) The above object is achieved by the following present invention.
That is, the present invention consists of two inventions, the first invention being a polyol component, a polyisocyanate component,
A hydroxyl group-containing vinyl chloride/vinyl acetate copolymer, a surfactant, and a pigment are dissolved and dispersed in a solvent, and the hydroxyl group-containing vinyl chloride/vinyl acetate copolymer contains 100 parts by weight (polyol component + polyisocyanate component). 10 to 40 parts by weight, and the surfactant accounts for 0.5 to 10% by weight in the ink composition.
An ink composition capable of forming a writable surface on a plastic film, and a second invention provides a surface of a plastic film, characterized in that the ink composition is coated and cured to form a writable surface. This is a processing method. (Function) By forming a highly flexible cross-linked polyurethane resin layer containing pigments etc. on the surface of the plastic film, it improves writing, stamping and printability for various writing instruments, stamps, vermillion ink, printing, etc. It is possible to form an excellent surface. (Preferred Embodiment) The film-forming component in the ink composition of the present invention is mainly composed of a polyurethane-forming component, and also contains a vinyl chloride/vinyl acetate copolymer that has good compatibility and contains a hydroxyl group. There is. The polyurethane forming component consists of a polyol component and a polyisocyanate component.
Polyester polyols, polyether polyols, polyester polyether polyols, polycarbonate polyols, etc. are available on the market under product names such as Sample 1B series (manufactured by Sanyo Kasei), Urestone (manufactured by Kao), and Seikabond (manufactured by Dainichiseika Chemical Industries). can be obtained and used. On the other hand, the polyisocyanate component includes polyisocyanates such as naphthalene diisocyanate, xylylene diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, and polymethylene polyphenyl isocyanate, and dimers and trimers of these polyisocyanates, or polyfunctional combinations of the above polyisocyanates. Polyurethane polyisocyanates made of polyols and the like are used, and for example, preferred ones are available and used under trade names such as Takenate (manufactured by Takeda Pharmaceutical), Coronate (manufactured by Nippon Polyurethane Industries), and Duranate (manufactured by Asahi Kasei Industries). I can do it. The usage ratio of the polyol component and polyisocyanate component as described above is such that the molar ratio of OH/NCO is 2/
It ranges from 1 to 1/2, preferably from 1/1 to 1/1.5. In the present invention, a composition containing a polyol component and other components is formed in advance, and the ink composition is used as a so-called two-component type in which a polyisocyanate component is added immediately before use. The above-mentioned two components are preferably used in a total amount of about 10 to 50% by weight based on 100 parts by weight of the ink composition of the present invention. The film-forming components of the ink composition of the present invention include other film-forming components such as vinyl chloride/vinyl acetate copolymer in addition to the polyurethane-forming components described above. Examples of vinyl chloride/vinyl acetate copolymers are available and used under trade names such as VMCC, VMCH, VAGH (all manufactured by UCC), 1000G, 1000GKT, and 1000CK (all manufactured by Denki Kagaku Kogyo), etc. . Among these are VAGH, 1000G and
Those having a hydroxyl group at the end, such as 1000GKT, are particularly effective, and can also be used as the above-mentioned polyol component. By using such a vinyl chloride/vinyl acetate copolymer in a ratio of about 10 to 40 parts by weight based on 100 parts by weight of the polyurethane forming components (polyol component + polyisocyanate component), relatively flexibility can be achieved. Because a certain layer is formed, it is suitable for processing relatively thin (10 to 50 μm) and highly flexible films such as polyethylene, polypropylene, and polyester.
Suitable as a paper substitute for postal applications such as postcards. The ink composition of the present invention further contains a pigment. These pigments increase the hardness of the film and the absorption of ink, and for example, extender pigments such as titanium oxide, calcium carbonate, magnesium carbonate, aluminum silicate, silica, and kaolin clay can be used.
Furthermore, other colored pigments can also be used. In addition, both hydrophilic silica and hydrophobic silica can be used as the silica, and by using this hydrophobic silica together with the surfactant described below, the cellophane film formed by using this hydrophobic silica can be used. This is preferable because the peel strength is improved and the erasability of pencil-written characters with an eraser is improved. These pigments are preferably used in an amount of about 5 to 40% by weight in the ink composition. Furthermore, the ink composition of the present invention contains a surfactant. By using a surfactant in combination, the ink absorbency of the film is improved, and excellent drying and adhesion properties can be obtained for water-based pens, water-based stamp inks, and water-soluble adhesives such as stamps and labels. Any of anionic, nonionic, and cationic surfactants are effective as surfactants, but particularly preferred are sodium salts of sulfuric esters of saturated higher alcohols, sodium alkylnaphthalene sulfonates, and polyalkylene glycols. Anionic surfactants with excellent wetting effects such as sulfuric ester sodium salt, sodium dialkyl sulfone succinate, etc. are preferred. These surfactants are present in the ink composition of the present invention in amounts ranging from 0.5 to
Preferably, it is used in an amount accounting for 10% by weight. Further, the ink composition of the present invention can contain wax. Wax has the effect of improving the scratch strength of the formed film, and can be obtained and used, for example, under trade names such as Hiwax (manufactured by Mitsui Petrochemical Industries) and Sun Wax (manufactured by Sanyo Chemical). These waxes are preferably used in an amount of about 0.5 to 3% by weight in the ink composition of the present invention. The ink composition of the present invention can be obtained by dissolving or dispersing the above components in a common organic solvent such as ethyl acetate, methyl ethyl ketone, toluene, alcohol, or the like. This ink formation may be carried out using a general dispersing machine or the like, and the manufacturing method itself is not particularly limited. In addition, the solid content of the obtained ink composition is approximately 25 to 60% in consideration of its coating properties.
It is preferable to adjust the weight percent and viscosity to about 200 to 1500 cps (25°C) before use. The method for surface treatment of plastic film of the present invention is mainly characterized by using the above-mentioned ink composition of the present invention.As the plastic film, polyethylene, polypropylene, and polyester, which have been conventionally used for various purposes, can be used. ,
Films, sheets, or synthetic papers made of polyvinyl chloride, etc., and envelopes, postcards, etc. made by processing these.
The form thereof is not particularly limited, such as base paper for drawings, various cards, various bags, packages, etc. Further, as a method for coating the above-mentioned plastic film, any printing or coating method such as silk screen, gravure coating, roll coating, etc. may be used. Further, the coating amount may generally be about 4 to 20 g/m ² in terms of solid content. After coating, the desired coating is formed by drying and curing at an appropriate temperature. (Effects) According to the present invention as described above, by forming a cross-linked polyurethane resin layer containing a pigment etc. on the surface of a plastic film, it is possible to improve writing performance and printing properties for various writing instruments, stamps, vermillion ink, printing, etc. It is possible to form a surface with excellent properties, printability, etc. (Example) Next, the present invention will be explained in more detail by giving examples and comparative examples. In the text, parts or percentages are based on weight unless otherwise specified. Example 1 Samplerene (30% toluene/isopropyl alcohol 2/1 solution, manufactured by Sanyo Chemical) 40.0 parts Vinyl chloride/vinyl acetate copolymer (1000GKT,
20% solution, manufactured by Denki Kagaku Kogyo) 20.0 parts Titanium oxide (R820, manufactured by Ishihara Sangyo) 27.0 parts Silica (Thyroid 308, manufactured by Fuji Davison)
8.0 parts Wax (Sanwax, manufactured by Sanyo Kasei) 1.0 parts Ethyl acetate 29.0 parts Toluene 20.0 parts Anionic surfactant (manufactured by Nippon Nyukazai) 1.0 parts Disperse the above ingredients with a sand mill, and immediately before use, add polyisocyanate (Coronate L, Japan) Polyurethane Kogyo Co., Ltd.) was added and mixed to obtain an ink composition of the present invention. Example 2 and Comparative Examples 1 and 2 Ink compositions of the present invention and comparative examples having the following compositions were obtained in the same manner as in Example 1. In all Examples, 5 parts of Coronate L was added and mixed immediately before use. Example 2 Samplerene (30% toluene/isopropyl alcohol 2/1 solution, manufactured by Sanyo Chemical) 40.0 parts Vinyl chloride/vinyl acetate copolymer (1000CK,
30% solution, manufactured by Denki Kagaku Kogyo) 20.0 parts Titanium oxide (R820, manufactured by Ishihara Sangyo) 27.0 parts Silica (Thyroid 308, manufactured by Fuji Davison)
8.0 parts Wax (Sanwax, manufactured by Sanyo Kasei) 1.0 parts Ethyl acetate 29.0 parts Toluene 20.0 parts Anionic surfactant (manufactured by Nippon Nyukazai) 1.0 parts Comparative example 1 Chlorinated polypropylene (Super Chron 803M,
Solid content 30%, Sanyo Kokusaku Pulp) 40.0 parts Titanium oxide (R820, manufactured by Ishihara Sangyo) 25.0 parts Silica (Thyroid 308, manufactured by Fuji Davison)
8.0 parts Wax (Sanwax 131, manufactured by Sanyo Chemical)
1.0 parts Methyl ethyl ketone 10.0 parts Toluene 16.0 parts Comparative example 2 4/1 Nitrified cotton varnish (solid content 25%, manufactured by Asahi Kasei Industries)
10.0 parts Polyamide varnish (Sunmide S-40E, solid content 40%, manufactured by Sanyo Kasei) 40.0 parts Titanium oxide (R820, manufactured by Ishihara Sangyo) 25.0 parts Silica (Thyroid 308, manufactured by Fuji Davison)
8.0 parts Wax (Sanwax 131, manufactured by Sanyo Chemical)
1.0 parts Ethyl acetate 4.0 parts Toluene 8.0 parts Isopropyl alcohol 7.0 parts The above ink composition of the present invention and the ink composition of the comparative example were treated with a bar coater #8 on a polypropylene film (thickness 25 μm) at a solid content of 5 g/m ² After aging at 40°C for 2 days, a test was conducted and the results shown in Table 1 below were obtained. The test method and evaluation criteria are as follows. (1) Sellotape peel strength: Nichiban Sellotape (width 25 mm) was attached to the coated surface, the surface was rubbed twice with a finger to make the adhesion uniform, and a peel test was performed. ◎: No peeling of the film even after 2 times ○: No peeling of the film after 1 time △: 20% or less peeling after 1 time ×: 20% or more peeling after 1 time (2) Scratch strength : Rub the paint surface with a nail to determine the extent of scratches. 〇: No scratches △: Slight scratches ×: Scratches (3) Massage strength: Determined by hand massaging the film 10 times. 〇: Paint film with no lifting △: Paint film with lifting of 20% or less ×: Paint film with lifting of 20% or more (4) Written test: Mark the coated surface with a pencil (HB), (a) , a ballpoint pen (b), an oil-based pen (c), and a water-based pen (d), and the density and drying properties were compared with those written on paper. 〇: Equivalent to or better than paper △: Slightly inferior to paper ×: Inferior to paper (5) Eraser suitability: Ability to record characters on the coated surface with an HB pencil and erase them with an eraser. compared. 〇: Things that disappear well △~〇: Things that are somewhat difficult to disappear. △: Things that are difficult to erase ×: Things that do not disappear. (6) Stamp pasting suitability: Stamps are pasted onto the coating surface, and the time taken until they no longer peel off is compared with the state of peelability. 〇: The paper is equivalent to paper and can be cut when peeled off. △: The paper does not tear when peeled off, but it is strong. ×: There is no resistance when peeled off. (7) Suitability for offset printing: Offset printing is performed on the coated surface to improve transferability. and determined by adhesion test. ○: Good transferability and adhesion △: Good transferability, but insufficient adhesion ×: Both are poor (8) Water resistance: After immersing the printed matter in room temperature water for 24 hours, a cellophane tape peeling test was performed. 〇: No peeling △: Less than 20% peeling ×: More than 20% peeling (9) Oil resistance: Perform the Gakushin type friction test 20 times on the coated surface with a cloth moistened with soybean oil and lard to observe changes in the coated surface. look. 〇: No change △: Slight change ×: Large change (10) Alcohol resistance: Wipe the coated surface 20 times with a cloth moistened with ethanol and observe the change in the surface. 〇: No change △: Less than 20% peeling ×: More than 20% peeling [Table]

Claims (1)

[Claims] 1. Polyol component, polyisocyanate component,
A hydroxyl group-containing vinyl chloride/vinyl acetate copolymer, a surfactant, and a pigment are dissolved and dispersed in a solvent, and the hydroxyl group-containing vinyl chloride/vinyl acetate copolymer contains 100 parts by weight (polyol component + polyisocyanate component). 10 to 40 parts by weight, and the surfactant accounts for 0.5 to 10% by weight in the ink composition.
An ink composition capable of forming a writable surface on plastic film. 2 polyol component, polyisocyanate component,
A hydroxyl group-containing vinyl chloride/vinyl acetate copolymer, a surfactant, and a pigment are dissolved and dispersed in a solvent, and the hydroxyl group-containing vinyl chloride/vinyl acetate copolymer contains 100 parts by weight (polyol component + polyisocyanate component). The ink composition is coated and cured to form a writable surface. A method for surface treatment of plastic film.