JPS59206470A - Coating composition - Google Patents

Abstract

PURPOSE:To provide a coating compsn. which has excellent coatability and adhesion to synthetic resin films or metallized films and can impart printability, by blending colloidal silica with a compsn. consisting of a specified group-contg. polyester and a specified saponified copolymer. CONSTITUTION:A coating compsn. is obtd. by blending 20-80pts.wt. colloidal silica having an average particle size of 0.1-10mu with 100pts.wt. compsn. consisting of 95-65wt% polyester (A) contg. sulfonate salt groups and 5-40wt% saponified vinyl chloride/vinyl acetate copolymer (B) having a vinyl acetate content of 2-30mol% and a degree of saponification of 5-100mol%. This compsn. has excellent adhesion to films composed of all kinds of materials and are useful in the field of packaging materials to be printed. Preferred examples of the substrates are synthetic resin films such as PE film, vinyl chloride film, etc. and films obtd. by metallizing one side or both sides of said synthetic resin films with metal such as gold, silver, zinc, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to a coating material that has excellent coating workability and adhesion and provides printability for synthetic resin films or metallized films in which metals are vapor-deposited. .

Various coating agents have been applied to improve the surface properties of synthetic resin films, for example, Japanese Patent Publication No. 52-2
Regarding polyester film in Publication No. 8470,
A coating composition coated with a saponified vinyl chloride-vinyl acetate copolymer, a methylolated amino resin, a non-drying oil-type alkyd resin, and an inorganic powder is known. Such a composition has excellent adhesion to the base film, and also has excellent printability and water resistance of the coating film. Coating materials that do this are expected to continue to show promise in the future. However, according to studies conducted by the present inventors, when such a composition is actually applied to a base material, the viscosity is unstable and the coating property is poor, resulting in uneven thickness of the coating film and a uniform coating surface. It has been found that it is not always easy to obtain this, and as a result, a large amount of solvent is required.

However, in view of the above problems, the inventors of the present invention conducted intensive research and found that (a) sulfonic acid group-containing polyester 95
~60% by weight, (b) vinyl acetate content of 2~60% by mole
With respect to 100 parts by weight of a composition containing 5 to 40% by weight of a saponified vinyl chloride-vinyl acetate copolymer obtained by saponifying 5 to 100 mol% of Deroshi, an average particle size of 0.
It has been found that when 20 to 80 parts by weight of colloidal silica with a diameter of 1 to 10 .mu.m is blended, an excellent coating composition free from the above-mentioned drawbacks can be obtained, and the present invention has been completed.

The composition of the present invention will be explained in more detail.

First, the sulfonic acid group-containing polyester (a) used in the present invention is usually any linear or branched resin having an intrinsic viscosity of 0.1 to 2.0, preferably 0.3 to 1.5. Ru. As a method for introducing a sulfonic acid group into polyester, conventionally known methods are used as appropriate, but representative methods include 1) Incorporation of a sulfonic acid group-containing polycarboxylic acid such as 5-dicumsulfoisophthalic acid and a polycarboxylic acid group into the polyester. Method of reacting a polybasic alcohol 2) A polybasic acid or a polyhydric alcohol having an unsaturated bond is reacted with an acidic sulfite to form a polybasic acid or polyhydric alcohol containing a sulfonic acid group, and this is used to react with a polybasic acid or a polyhydric alcohol containing an unsaturated bond. A method of reacting with an acid or a polyhydric alcohol.

3) A method of adding acidic sulfite to unsaturated bonds in unsaturated polyester.

4) A method in which a compound having an epoxy group and an acidic sulfite are reacted to form a sulfonic acid group-containing polyfunctional monomer, and this is reacted with a polybasic acid or a polyvalent alecol.

etc. In the polyester, the sulfonic acid group in the resin is usually 0.0005 to 60 mol%, more preferably o, o O, etc. from the viewpoint of water resistance of the coating composition.
It is preferable to introduce it in a range of 1 to 10 mol%.

Next, in the present invention, the component (b) has a vinyl acetate content of 2 to 60 mol% and 5 to 100 mol%, preferably 40 to 90 mol%, and more preferably 50 to 80 mol%.
It is necessary to use a saponified vinyl chloride-vinyl acetate copolymer obtained by saponifying the above component (a).

Among these copolymers, those having a degree of polymerization of 200 to 400 are particularly preferable from the viewpoint of the coating hardness of the resulting coating composition and the solubility in solvents. If the vinyl acetate content is less than 2 mol%, the solubility in solvents will decrease, resulting in a decrease in potato cultivation properties, and if it is more than 50 mol%, the softening point of the coating will decrease, resulting in a decrease in thermal stability. Undesirable. On the other hand, less than 2 mol%, that is, almost unsaponified vinyl chloride-ffl'
Adhesion to the film serving as the base material of the vinyl acid vinyl copolymer is extremely reduced, making it impossible to obtain the effects of the present invention. In addition, monomers having a low amount of copolymerizability with vinyl chloride and vinyl acetate, such as unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, or alkyl esters thereof, etc., may be used within a range that does not impair the effects of the present invention. It is of course possible to use unsaturated dicarboxylic acids such as maleic acid, hexamaric acid, and ichonic acid, or their anhydrides, and copolymers with monoalkyl esters, dialkylnisdales, and the like.

In the present invention, the (a) sulfonic acid group-containing polyester and (bl vinyl chloride-vinyl acetate copolymer saponified product) are mixed in a ratio of 95=5 to 60:40 (weight ratio), preferably 9
It is essential to mix at a ratio of 0:10 to 6:40. (
If the amount of component b) is less than 5% by weight, the strength and adhesion of the coating film will decrease, and if it is more than 40% by weight, the compatibility with solvents will tend to decrease, which is not preferable. In addition, in the present invention, superior effects can be expected compared to conventional ones due to the sulfonic acid group in the polyester, and when using a general polyester, the vinyl chloride-vinyl acetate copolymer has poor adhesion, workability, etc. A synergistic effect with saponified substances cannot be obtained.

In the present invention, the total of component (a) and component (b) is 100
Average particle size 0.1 to 10 μm based on weight part
It is preferably blended in an amount of 60 to 70 parts by weight rather than 0 parts by weight. If the amount is less than 20 parts by weight, printing suitability for water-based inks cannot be imparted.

Moreover, if the amount is more than 80 parts by weight, the thixotropic property of the composition becomes large and the workability becomes poor, which is not preferable. Commercially available colloidal silica can usually be used, but if the average particle size is 10 μm or more, the coating surface will not be uniform, causing problems in terms of appearance and feeling rough when touched.

Thus, a composition containing component (a), component (b), and colloidal silica is usually used after being dissolved in a known solvent.

Such solvents are not particularly limited, but typically include lower alcohols such as methanol, ethanol, propatool, and getanol, ethylene glycol, propylene glycol, butylene glycol, 1.4-butanediol, 1. Polyhydric alcohols such as butanediol,
Ketones such as acetone, methylethylgtone, dimethylchthone, diethylgtone, methylisobutylketone, ethylisobutylketone, lower alkyl esters such as methyl acetate, ethyl acetate, globil acetate, aromatic carbonization of benzene, toluene, xylene, etc. Examples include hydrogen.

Additives other than the colloidal silica, such as fillers, pigments, cross-linking agents, coupling agents, etc., may be added to the composition of the present invention as necessary to improve the performance of the coating film or for the purpose of improving the coating properties. .

Fillers include bentonite, organic bentonite, quartz powder, diatomaceous earth, glass powder, asbestos, etc. Pigments include titanium oxide, lucium carbonate, talc, lithopone, palicum sulfate, lucium sulfate, alumina, clay, carbon black, and phthalocyanine. Glue, navy blue, ultramarine, lake yellow, yellow lead, orca yellow, hand yellow,
Examples include Venkara, Lake Red, Chrome Vermilion, Phthalocyanine Green, and mixed pigments thereof.

As the crosslinking agent, known ones having functional groups such as ink mononate groups, carboxyl groups, and epoxy groups in their molecules, such as tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate,
Trimethylolpropane-tolylene diisocyanate adduct, polymethylene polyphenylinocyanate, succinic acid, glucuric acid, adipic acid, pimelic acid, azelaic acid, phthalic acid, isophthalic acid, terephthalic acid, bispher/-type A diglycidyl Ether, triglycidyl isocyanurate, etc. are used. As the coupling agent, any known coupling agent such as titanium, aluminum, silicone, etc. can be used.

Since the coating composition obtained by the present invention has excellent adhesion to films of all materials, the base material is not particularly limited, but it is particularly useful for packaging materials that require printing. Base materials used include polyethylene film, polypropylene film,
Synthesis 8 of polyethylene terephthalate, polyethylene terephthalate, and general polyester films, cellophane, polyamide films, vinylon films, vinyl chloride films, vinyl alcohol films, etc. are made into oil-based films, and one side of these films is Alternatively, a metal-deposited film in which metals such as aluminum, gold, silver, tin, zinc, and nickel are deposited on both sides is a typical and more preferable base material. Of course, it is also possible to coat general base materials other than those mentioned above, such as wood, metal, paper, etc.

When applying the composition of the present invention to a substrate, there are no particular restrictions on the method of application, but any commonly known method, such as brushing, roll coating, spray coating, etc., can be employed. The coating amount is usually 1 to 20 y/crA and the film thickness is 1 to 20 .mu. from the viewpoint of economical efficiency and coating film performance.

As mentioned above, the thus obtained film treated with the coating composition of the present invention can be usefully used for packaging materials that require printing, taking advantage of its characteristics.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Note that "Example Middle" is based on weight unless otherwise noted.

In addition, the intrinsic viscosity of the polyester in the example is 7 at 30°C.
f, This is a value measured using a mixed solution of normal tetrachloroequene at a ratio of 1:1 (weight ratio).

Example 20 parts of a composition consisting of a sulfonic acid group-containing polyester and saponified vinyl chloride-vinyl acetate copolymer as shown in Table 1 was used as a solvent, and 80 parts of a mixed solvent of toluene and methyl ethyl ketone at a ratio of 4:1 (weight ratio) was added. Dissolve using
Furthermore, the coroiglusilic force with an average particle size of 0.1 to 10 μm was
Added part. In addition to the colloidal silica, fillers shown in Table 1 were added and dispersed with a high-speed disperser to form a coating composition.

Each of the obtained coating compositions was applied to a film (thickness: 20 .mu.m) made of the materials shown in Table 1 to a dry film thickness of 10 .mu.m. Coating was performed using a roll coater, and drying was performed by passing the film through a hot air oven at an oven temperature of 80°C for 60 seconds.

The composition was examined for adhesion to various films, suitability for printing with oil-based inks and water-based inks, water resistance, and coating workability during coating. The results are shown in Table 2.

Comparative Example Coating compositions were obtained using the compositions shown in Table 1 in the same manner as in the Examples, and the coating compositions were applied to various films under the same conditions to examine their performance.

The results are also shown in Table 2.

The performance test was conducted as follows.

0 Adhesion to the base material Use a sharp blade to penetrate the coating film and apply a 2 mm x
100 base marks of 2 tmn were applied, and this was expressed as the number of base marks remaining on the base material after peeling off the cellophane tape.

Print with oil-based or water-based ink on the printable surface of 0 ink, rub it with gauze 15 seconds after printing, and rate the degree of bleeding of each ink in 5 stages (
Evaluation was made as follows: 5: No bleeding at all; 4: Slightly no bleeding; some bleeding; 2: Slightly noticeable bleeding; 1: Significant bleeding.

The O water-resistant coated film was immersed in deionized water at 50°C for 24 hours and then dried at 40°C for 2 minutes. This coating film was subjected to the same test as the adhesion test described above.

Claims (1)

[Claims] (a) 95 to 60% by weight of a sulfonic acid group-containing polyester (b) fff' e vinyl content is 2 to 0% by weight, and 5 to 100% by mole thereof is saponified. The average particle size is 0.1-1 for 100 parts by weight of a composition consisting of 5-40% by weight of saponified vinyl chloride-vinyl acetate copolymer.
Coating composition containing 20 to 80 parts by weight of 0 μm colloidal silica2.