JPS6348910B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention particularly relates to a coating material that has excellent coating workability and adhesion and printability for synthetic resin films or metal-deposited films obtained by vapor-depositing metals thereon. Various coating agents have been applied to improve the surface properties of synthetic resin films. For example, in Japanese Patent Publication No. 52-28470, saponified vinyl chloride-vinyl acetate copolymer, methylolated A coating composition coated with an 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, the present inventor has found that when such a composition is actually applied to a substrate, the viscosity is unstable and the coating properties are 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) a polyester containing sulfonic acid groups is 95 to 60% by weight, and (b) the vinyl acetate content is 2 to 30% by weight.
% by mole, and 5 to 100 mol% of the saponified vinyl chloride-vinyl acetate copolymer saponified product. Colloidal Silica 20
It has been found that an excellent coating composition free from the above-mentioned drawbacks can be obtained when 80 parts by weight is blended, and the present invention has been completed. The composition of the present invention will be explained in more detail. First, as the sulfonic acid group-containing polyester (a) used in the present invention, any linear or branched resin having an intrinsic viscosity of 0.1 to 2.0, preferably 0.3 to 1.5 is used. 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-sodium sulfoisophthalic acid, etc. Method for reacting polyhydric alcohols (2) A polybasic acid or polyhydric alcohol having an unsaturated bond is reacted with an acidic sulfite to form a sulfonic acid group-containing polybasic acid or polyhydric alcohol, which is then reacted with other polybasic acids or polyhydric alcohols. Or a method of reacting with polyhydric alcohol. (3) A method of adding acidic sulfite to the 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 polyhydric alcohol. etc. In the polyester, the sulfonic acid group in the resin is usually 0.0005 to 30 mol%, more preferably from the viewpoint of water resistance of the coating composition.
It is preferable to introduce it in a range of 0.001 to 10 mol%. Next, in the present invention, the component (b) has a vinyl acetate content of 2 to 30 mol% and 5 to 100 mol%, preferably 40 to 90 mol%, more preferably 50 to 80 mol% of the vinyl acetate content is saponified. It is necessary to use a saponified vinyl chloride-vinyl acetate copolymer together with the above component (a). Especially among these copolymers, the degree of polymerization is 200.
-400 is preferable from the viewpoint of coating film hardness of the resulting coating composition, compatibility with solvents, etc. If the vinyl acetate content is less than 2 mol%, the solubility in solvents will decrease, resulting in a decrease in workability, and if it is more than 30 mol%, the softening point of the coating film will decrease, resulting in a decrease in thermal stability, so it is preferable. do not have. On the other hand, if the vinyl chloride-vinyl acetate copolymer is less than 2 moles, that is, is hardly saponified, the adhesion to the film serving as the base material is extremely reduced, and the effects of the present invention cannot be obtained. A small amount of monomer copolymerizable with vinyl chloride and vinyl acetate, such as unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, or alkyl esters thereof, maleic acid, fumar, etc., may be used as long as the effects of the present invention are not lost. Of course, it is possible to use copolymers of acids, unsaturated dicarboxylic acids such as itaconic acid, or their anhydrides, monoalkyl esters, dialkyl esters, and the like. In the present invention, the above (a) sulfonic acid group-containing polyester and (b) saponified vinyl chloride-vinyl acetate copolymer are mixed in a ratio of 95:5 to 60:40 (weight ratio), preferably 90:10 to 60:40. Mixing is essential.
If 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, vinyl chloride-vinyl acetate copolymer has lower adhesion, workability, etc. A synergistic effect with saponified substances cannot be obtained. In the present invention, 20 to 80 parts by weight, preferably 30 to 70 parts by weight of colloidal silica having an average particle size of 0.1 to 10 μm is blended to 100 parts by weight of components (a) and (b) in total. If it is less than 20 parts by weight, printing suitability, especially for water-based inks, cannot be imparted.
Moreover, if the amount is more than 80 parts by weight, the thixotropic properties of the composition will increase, resulting in poor workability, 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 comprising 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, propanol, butanol, ethylene glycol, propylene glycol, butylene glycol, 1,4-butanediol, 1,3
- Polyhydric alcohols such as butanediol, ketones such as acetone, methyl ethyl ketone, dimethyl ketone, diethyl ketone, methyl isobutyl ketone, ethyl isobutyl ketone, lower alkyl esters such as methyl acetate, ethyl acetate, propyl acetate, benzene, toluene, xylene Aromatic hydrocarbons such as In order to improve the performance of the coating film, the composition of the present invention includes:
Alternatively, additives other than the colloidal silica, such as fillers, pigments, crosslinking agents, coupling agents, etc., may be added as necessary for other purposes. Fillers include bentonite, organic bentonite, quartz powder, diatomaceous earth, glass powder, asbestos, etc.; pigments include titanium oxide, calcium carbonate, talc, lithopone, barium sulfate, calcium sulfate, alumina, clay, carbon black,
Phthalocyanine blue, navy blue, ultramarine, lake yellow, yellow lead, orca yellow, hansa yellow,
Red Garla, Lake Red, Chrome Vermillion,
Examples include phthalocyanine green and mixed pigments thereof. As the crosslinking agent, known ones having a functional group such as an isocyanate group, a carboxyl group, or an epoxy group in the molecule, such as tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, trimethylolpropane-tolylene diisocyanate adduct, polymethylene polyphenyl isocyanate,
Succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, phthalic acid, isophthalic acid, terephthalic acid, bisphenol type A diglycidyl ether, triglycidyl cyanurate, etc. are used. As the coupling agent, any known coupling agent such as titanium, aluminum, silicone, etc. can be used. However, 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 in the field of packaging materials that require printing. Base materials used in this field include polyethylene film, polypropylene film, polyethylene terephthalate, polybutylene terephthalate, and other general polyester films, cellophane, polyamide film, vinylon film, vinyl chloride film, vinyl alcohol film, etc. Synthetic resin films, and aluminum, gold, silver, etc. on one or both sides of these films.
A typical and more preferable base material is a metal-deposited film on which a metal such as tin, zinc, or nickel is deposited. 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 g/cm ² and the film thickness is 1 to 20 μm from the viewpoint of economy and coating performance. As mentioned above, the film treated with the coating composition of the present invention obtained in this way can be usefully used, especially for packaging materials requiring printing, by taking advantage of its characteristics. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that "Example Middle" is based on weight unless otherwise specified. In addition, the intrinsic viscosity of the polyester in the example is a value measured at 30°C using a mixed solution of phenol-tetrachloroethane in a ratio of 1:1 (weight ratio). Example A mixed solvent of toluene and methyl ethyl ketone at a ratio of 4:1 (weight ratio) using 20 parts of a composition consisting of a sulfonic acid group-containing polyester and a saponified vinyl chloride-vinyl acetate copolymer as shown in Table 1 as a solvent.
Dissolve using 80 parts and further reduce the average particle size to 0.1 to 10 μm.
5 parts of colloidal silica were added. In addition to the colloidal silica, fillers shown in Table 1 were added and dispersed using a high-speed disperser to obtain 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. Regarding the composition, adhesion to various films, printability with oil-based inks and water-based inks,
Water resistance and coating workability during coating were investigated. 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 sulfonic acid group-containing polyester resin used in each experiment was manufactured by the following method. No.: 1 Terephthalic acid 166.1g, Isophthalic acid 166.1
g, dimethyl 5-sodiosulfoisophthalate
11.8 g and 186.2 g of ethylene glycol in the presence of zinc acetate and an anion trioxide catalyst
Esterification is performed at 220℃, then 0.5 to 1.0
Polycondensation was carried out under a vacuum of mmHg to obtain a sulfonic acid group-containing polyester having a sulfonic acid group content of 2 mol % and an intrinsic viscosity of 0.81. No.: 2 Isophthalic acid 319.0g, maleic anhydride 3.9
An unsaturated polyester was obtained by condensing 186.2 g of ethylene glycol and 186.2 g of ethylene glycol in the presence of a zinc acetate catalyst. Next, 4.3 g of acidic sodium sulfite was added to 200 g of the unsaturated polyester at 180 to 190°C to obtain a sulfonic acid group-containing polyester having a sulfonic acid group content of 2 mol % and an intrinsic viscosity of 0.76. No.: 3 Terephthalic acid 166.1g, Isophthalic acid 166.1g
g, 186.2 g of ethylene glycol, and 19.3 g of 2-sodiosulfo-1.4-butanediol were subjected to an esterification reaction at 140 to 220°C in the presence of a dibutyltin oxide catalyst, and further under a vacuum of 0.5 to 1.0 mmHg.
Polycondensation was carried out at 250°C to obtain a sulfonic acid group-containing polyester having a sulfonic acid group content of 5 mol % and an intrinsic viscosity of 0.8. No.: 4 to 9, No.: 13 to 14 Assuming that the amount of dimethyl 5-sodiosulfoisophthalate used in No. 1 is 30.0 g, the sulfonic acid group-containing polyester has a sulfonic acid group content of 10 mol% and an intrinsic viscosity of 0.80. I got it. No.: 11 In No. 2, the amounts of maleic anhydride and acidic sodium sulfite were changed to 65.0 g and 84.0 g, respectively, to obtain a sulfonic acid group-containing polyester having a sulfonic acid group content of 30 mol% and an intrinsic viscosity of 0.65. No.: 11-12 Produced in No. 1 by omitting the use of dimethyl 5-sodiosulfoisophthalate.

[Table] ○Explanation of abbreviations
PET: Polyethylene terephthalate, PP: Polypropylene

[Table] The performance test was conducted as follows. Adhesion to the Γ substrate: Apply 100 2 mm x 2 mm grids to the substrate using a sharp blade, penetrating the coating film, and display the number of grids remaining on the substrate by peeling off cellophane tape. did. Printability of Γ ink Print on the painted surface with oil-based or water-based ink, rub it with gauze 15 seconds after printing, and rate the degree of bleeding of each ink in 5 grades (5: no bleeding, 4: almost no bleeding, 3: no bleeding) There is some bleeding,
Evaluation was made as follows: 2: noticeable bleeding; 1: significant bleeding). ΓWater Resistance Place the coated film in deionized water at 50℃ for 24 hours.
After soaking for an hour, it was 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] 1 (a) Sulfonic acid group-containing polyester 95-60
Weight% (b) Composition 100 comprising 5 to 40% by weight of a saponified vinyl chloride-vinyl acetate copolymer having a vinyl acetate content of 2 to 30 mol% and 5 to 100 mol% of it being saponified. Average particle size 0.1 to parts by weight
A coating composition containing 20 to 80 parts by weight of 10 μm colloidal silica.