JPS6015441A - Coating of molding - Google Patents

Abstract

PURPOSE:To improve the gas barrier property of a molding, by coating the surface of the molding with a specified (meth)-acryl-modified oligomer and a vinyl monomer and polymerizing them. CONSTITUTION:A molding (e.g., polyolefin film) is coated with a polymer film of a three-dimensional network structure by coating the surface of the molding with a composition comprising (A) about 5-50mol% epoxy-, polyurethane-, polyolef in glycol-, or polyester-(meth)acrylate [e.g., bisphenol A-derived epoxy acrylate (MW of about 300-6,000), (B) about 95-50mol% vinyl monomer (e.g., neopentyl glycol diacrylate), and (C) about 0.5-20wt%, based on the total of components A and B, photopolymerization initiator (e.g., benzophenone), and irradiating electromagnetic waves at a wavelength in the range of 200-500nm to photopolymerize the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for coating a molded article, and more particularly, the present invention relates to a method for coating a molded article, and more particularly, the present invention relates to a method for coating a molded article with a specific (meth)acrylic modified e, oligomer, vinyl monomer, and photopolymerization initiator on the surface of the molded article. The present invention relates to a method for coating a molded object, in which a composition comprising a compound and a polyolefin agent is applied and the coating film is cured by irradiation with ultraviolet rays, and in particular to a method for improving the gas barrier properties of a polyolefin molded object.

Conventionally, in order to improve the gas barrier properties of plastic films, sheets, containers, etc., resins with excellent gas barrier properties, such as saponified ethylene-vinyl acetate copolymers, polyamide resins, and polyester resins, have been combined with dry laminates or other resins. A method such as forming a laminate by extrusion molding, or coating and drying vinylidene chloride copolymer in the form of emulsion polymerized latex on a carrier film, container, etc.
It is also being coated with a film.

However, in order to make the laminate thinner by the thickness of the layer, a highly durable material is required, and non-polar resins such as polyolefins are compatible with the M layer resin. A process to improve interlayer adhesion is required.
Shiros requires many steps, which increases costs. on the other hand,
Although the method of applying vinyl chloride + 7-dene copolymer is a method that easily imparts gas barrier properties, the pinhole resistance is not necessarily sufficient.

The present invention relates to a conventionally known method for attaching a molded article,
As a result of various studies aimed at improving these problems, especially in methods for improving barrier properties, we found that it is effective to polymerize a specific (meth)acrylic-modified oligomer in combination with a vinyl monomer. It was discovered and completed.

That is, the present invention provides for the surface or at least one side of a molded product to be coated with (1) epoxy (meth)acrylate, polyurethane (meth)acrylate, polyolefin glycol (meth)acrylate, or polyester (meth)acrylate, (2) vinyl A method for coating molded articles, in particular a gas barrier coating for polyolefin molded articles, characterized in that a composition comprising a monomer and (3) a photopolymerization initiator is applied, and then the coating film is cured by irradiating ultraviolet rays. The present invention relates to a method for improving properties and oil resistance.

Examples of molded products in the present invention include plastic films, sheets, containers, woven or nonwoven fabrics, paper, and other arbitrary molded products.

Among these, polyolefins such as ethylene,
Homopolymers of α-olefins such as propylene, 1-butene, 1-hexene, 1-hexene, 3-methyl to 1-butene, 4-methyl-1-pentene, or one of the above monomers and other α-olefins. Molded products made of copolymers with olefins or mixtures thereof, such as films, sheets, containers, etc., are preferred. Further, the polyolefin may contain an olefin-based elastomer.

The epoxy (meth)acrylate, polyurethane (meth)acrylate, polyolefin glycol (meth)acrylate or polyester (meth)acrylate used in the present invention has a molecular weight of 300 to 6,
000, preferably 1,000 to 3,000, oligomers having two or more polymerizable functional groups, that is, polymerizable double bonds, and those having acrylic or methacrylic double bonds. In the house, epoxy (
As for methacrylates, acrylic acid mixtures on epoxy resins having glycidyl groups at the terminals are obtained by reacting methacrylic acid and the like, such as bisphenol A type epoxy acrylates. As for Ushita, polyurethane (meth)acrylate,
Polyurethane resin with incyanate group at the end,
Compounds having a vinyl group and a hydroxyl group in the molecule, such as 2-
Examples include those made by reacting hydroxyethyl acrylate or methacrylate. Examples of polyolefin glycol (meth)acrylates include diacrylic esters and dimethacrylic esters of polyethylene glycol. Furthermore, examples of polyester (meth)acrylates include polyesters made of phthalic anhydride and diethylene glycol treated with acrylic acid or methacrylic acid. These (meth)acrylic modified oligomers can be used in combination.

Vinyl monomers used in the present invention include monofunctional or polyfunctional vinyl compounds that break down reactive vinyl groups, such as acrylic acid and its derivatives, styrene and its derivatives, vinyl esters, and vinyl ethers. , vinyl ketone, etc.

Examples of acrylic acid and its derivatives include acrylic acid, acrylic ester, acrylamide, acrylonitrile, methacrylic acid, and methacrylic ester. Examples of styrene and its derivatives include styrene, /N D saponified styrene, α-methylstyrene, vinyltoluene, methoxystyrene, and divinylbenzene. Examples of the vinyl ester include vinyl acetate, vinyl propionate, vinyl stearate, and vinyl benzoate. Examples of the vinyl ether include vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether.

Examples of the vinyl ketone include methyl vinyl ketone and ethyl vinyl ketone.

Among these vinyl monomers, neopentyl glycol diacrylate, dimethylaminoethyl methacrylate, hydroxyethyl acrylate, acrylonitrile, butyl acrylate, trimethylolpropane triacrylate and the like are preferred. The above vinyl monomers may be used alone or in combination of two or more.

Examples of photopolymerization initiators used in the present invention include compounds such as benzoin alkyl ether, benzophenone, and benzoin. , N-dimethylaniline and the like can be used in combination.

The above-mentioned epoxy (meth)acrylate, polyurethane (
The mixing ratio of the composition consisting of meth)acrylate, polyolefin glycol (meth)acrylate or polyester (meth)acrylate (hereinafter referred to as oligomer), a vinyl monomer, and a photopolymerization initiator is such that the oligomer is in the range of 5 to 50 moles; Preferably 10 to 40 moles, 95 to 50 moles of vinyl monomer, preferably 90 to 60 moles, 0.5 to 2° of the weight of the photopolymerization initiator or the total weight of oligomer and vinyl monomer. Weight factor, preferably 1 to 1o weight factor.

If the proportion of the oligomer in the above composition is less than 5 moles, the three-dimensional network molecular structure of the sieve molecular film obtained by polymerization will be insufficient, resulting in a decrease in barrier properties, which is undesirable. Moreover, if the oligomer exceeds 50 molar ratio, the viscosity increases and the workability deteriorates, which is not preferable.

When mixing oligomers, vinyl monomers, and photopolymerization initiators, they are usually mixed by stirring without using a solvent as long as it does not affect the workability of the application, but if necessary, a volatile solvent may be used. Good too.

Next, in order to form a thin film layer of this composition on the surface of the molded article, for example, dip coating, gravure roll, air spray, spray, roll coater 1 brush, etc., are used. There is a way to apply it.

The ultraviolet rays used as a curing energy source for the composition in the present invention are optically active electromagnetic waves, usually 200 mμ.
It includes electromagnetic waves in the range of ~500 mμ. Sources of this ultraviolet light include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultraviolet fluorescent lamps, and carbon arc lamps, all of which are useful for the purpose of curing, but high-pressure mercury lamps are effective in shortening curing time. preferable. The above ultraviolet radiation source,
One type or a combination of two or more types can be used. In addition, the UV irradiation time varies depending on the type of composition, the content of photopolymerization initiator and sensitizer contained in the composition, the type and output of the light source used for irradiation, the distance from the light source to the surface of the object to be coated, etc. However, by adjusting these conditions, the process can be completed within one minute, preferably within several seconds.

As described above, according to the present invention, the surface of the molded product is formed by photopolymerizing the 11 composition consisting of an oligomer, a vinyl monomer, and a photopolymerization initiator, and forming a three-dimensional network molecular structure of the resulting polymer film. It is possible to improve gas barrier properties, as well as impart heat resistance, strong scratch resistance, surface smoothness, and antistatic properties.

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

In addition, the test method of the example is as follows.

(1) Oxygen permeation amount Gas permeability tester (Modθrn
Measured using the isobaric measurement method using CONTR018 (0XTRAN-100).

(2) Haze JISK6714 (3) Gloss 8STM D 2457 (4) Heat seal heat resistant Pressure 2 kg / 2 kg from the coating surface with a heat plate sealer
Heat press with Crn2 for 2 seconds and display the maximum temperature that does not shrink or melt.7.

(5) Scratch Resistance The scratch resistance on a pencil drawing line under a load of 1001 is expressed by the hardness of the pencil (NEMA method).

Examples 1 to 3 Epoxy acrylate (average molecular weight II 1000) obtained by reacting bisphenol A diglycidyl ether (part name: Ciel Ebico 1001) with acrylic acid (hereinafter referred to as PEDA) and droxyethyl acrylate. A photocurable composition was prepared by adding an amount of penzoin inglovyl ether corresponding to 2 parts of the total weight of the mixture to each of the proportions shown in 1 and mechanically stirring and mixing for 30 minutes.

Next, 30μ thick low density polyethylene (density -0.9
19) The above photopolymerizable composition was applied to the surface of the film (hereinafter referred to as LDPFi) to a thickness of 35 μm to a surface tension of 37 d, yr1θ/Cm by corona discharge treatment, and then exposed to a high-pressure mercury lamp. (aow/1M) and height 1
It was cured by irradiating ultraviolet rays from the 0C7F+ position for 30 seconds. Table 1 shows the amount of oxygen permeation of the obtained film.

Examples 4 to 6 In addition to Example 1, neopentyl glycol diacrylate was used instead of hydroxyethyl acrylate, and a reaction product of polyethylene glycol and tolylene diin cyanate was treated with hydroxyethyl acrylate instead of PEDA. Polyurethane diacrylate (average molecular weight 3000) of polyether thread prepared by
Except that polyester diacrylate (average molecular z1ooo) prepared by reacting acrylic acid with polyester made from phthalic anhydride and diethylene glycol (hereinafter referred to as PUDA) (hereinafter referred to as PSDA) was used in the proportions shown in Table 1. A photocurable composition was prepared, applied and irradiated with ultraviolet rays in the same manner, and the results are also listed in Table 1.

Comparative Example 1 In the case where hydroxyethyl acrylate was used alone, a photocurable composition was prepared, applied, and irradiated with ultraviolet rays in the same manner as in Example 1, and the results are also shown in Table 1.

Comparative Example 2 Polybutadiene diacrylate (average molecular weight 2500'
), (hereinafter referred to as PBD8) and neopentyl glycol diacrylate in the proportions shown in Table 1, a photocurable composition was prepared, applied, and irradiated with ultraviolet rays in the same manner as in Example 1. are also listed in Table-1.

Examples 7 to 10 A photocurable composition was prepared and applied in the same manner as in Example 1 except that the vinyl monomers and their blending ratios were as shown in Table 2. Ultraviolet irradiation was performed, and the results are shown in Table 2.

1. For reference, the LD'PE used in Example 1
A similar test was conducted on the same film without any treatment, and the results are also listed in Table 2.

Examples 11-13 In Example 1, a 30μ thick film was used instead of the LDPK film.
High-density polyethylene (density = o, 9ss) (hereinafter HD
Application of the photopolymerizable composition and irradiation with ultraviolet rays were carried out in the same manner except that a 30μ thick unstretched polypropylene (hereinafter referred to as CPP) film and a 30μ thick stretched polypropylene (hereinafter referred to as OPP) film were used. Example 14 PgDA 18.7 mol, polyethylene glycol diacrylate (average molecular weight 350) 28.2 mol, dimethylamine ethyl methacrylate 56.1 mol, and a mixture thereof. A photopolymerizable composition was prepared by mechanically stirring and mixing penzoin inglobyl ether in an amount equivalent to two parts by weight of the total weight of .

Next, I(DPE (density=o,
? 5x) 201 narrow-mouth cylindrical bottle (surface size 0.37m”
) was treated with a gas flame to reduce the surface tension to 40 dyne.
The above-mentioned photopolymerizable composition was applied with a brush onto the surface of 20μ and 40μ thick, respectively. The painted bottle was irradiated with ultraviolet rays for 30 seconds at a distance of 10 crn from a high-pressure mercury lamp to form a cured coating film.

The resulting cured coating was flexible, adhered well to polyethylene bottles, and was resistant to deformation of the bottles.

The bottle subjected to this treatment was filled with Shiraishi Cold Ganrin (trade name) of VC 20t, sealed, and placed in a constant temperature and humidity chamber at 50°C and 50 RH, and the permeability of Ganrin was completely investigated based on the change in the weight of the bottle over time. Ta. The test period was 14 days, and during this period the weight loss of Ganlin progressed linearly even in the Izuno1 bottle. Table 4 shows the average permeation amount and scratch resistance.
It was shown to.

For reference, a similar test was conducted on the same polygotylene bottle used in Example 14 without the treated segment ζ, and the results are also listed in Table 4. Ryo Hara −

Claims (1)

[Claims] (1) Epoxy (meth)acrylate, polyurethane (meth)acrylate, polyolefin glycol (meth)acrylate or polyester (
meth)acrylate, (2) vinyl monomer and (5)
1. A method for coating a molded article, which comprises applying a composition comprising a photopolymerization initiator and then curing the coating by irradiating the coating with ultraviolet rays.