JP2016160345A - Solvent-based thermosetting type top coating varnish for metal container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solvent-based thermosetting type top coating varnish for metal container making smooth transportation available even in a high speed transportation process during manufacturing a can, while forming convexoconcave shape on a coating surface by adding a filler with constant particle diameter as a varnish for metal container at a constant ratio and exhibiting non-slip effect when man hold in hands.SOLUTION: There is provided a solvent-based thermosetting type top coating varnish for metal container containing an urethane resin bead having average particle diameter of 6 to 110 μm and having kinetic friction coefficient of a cured coating surface after heating in a range of 0.2 to 1.0 when a measurement speed is 2 mm/s and increase rate of kinetic friction coefficient of 20% or less when the measurement speed is increased from 2 mm/s to 40 mm/s.SELECTED DRAWING: None

Description

  The present invention relates to a thermosetting solvent-based paint applied to an outermost layer of a metal container such as a beverage can and a laminate using the same.

  The coating agent applied to metal containers such as beverage cans is applied to protect the surface of the base (rust prevention, etc.), maintain gloss, and provide slipperiness (productivity, etc.). For the same reason, a laminated can formed by attaching a polyethylene terephthalate film is coated with OP varnish on the outermost layer.

  In recent years, these varnishes have a technique of prescribing resin beads and the like as a design effect to form a concavo-convex coating film (Patent Document 1), and a technique for producing an anti-slip effect by foaming an undercoat using foamable microcapsules (patent) Reference 2) is being used. However, when a non-slip effect is imparted to a metal can, etc., in a content filling process in which a large amount of metal cans are conveyed at high speed while in contact, smooth conveyance cannot be performed unless there is a certain slip property, Although it causes production trouble, no specific content has been proposed so far that can solve the above-mentioned problems.

JP 2005-112377 A JP2003-1555036

  The object of the present invention is to form a concavo-convex shape on the surface of the coating film by adding a filler with a fixed particle size at a fixed ratio as a varnish for a metal container, and to exhibit an anti-slip effect when held by a human hand. On the other hand, the object is to provide a solvent-based thermosetting topcoat varnish for metal containers that enables smooth conveyance even in a high-speed conveyance process during can production.

  In general, the anti-slip effect when a metal can is held by hand is more advantageous as the dynamic friction coefficient value is higher, and the smooth conveyance during production is more advantageous as the dynamic friction coefficient value is lower. Tend to. However, the speed at which the finger touches the surface of the metal can coating when moving a person holding the metal can (when you feel slippage) and the speed at which the cans come into contact during high-speed transport in the production of metal cans. Therefore, it is possible to achieve both of these performances by controlling the value of the dynamic friction coefficient in the change of the contact speed.

  The inventors have adopted a combination of a specific resin and a resin bead having a specific particle size, so that the dynamic friction coefficient value is in a low value range when measured at a low speed, and when measured at a high speed. As a result, the present inventors have found that the rate of increase in the dynamic friction coefficient can be controlled at a certain level.

  That is, the present invention is a thermosetting topcoat varnish containing urethane resin beads having an average particle diameter of 6 to 110 μm, and the dynamic friction coefficient value on the surface of the cured coating film after heating is measured at a measurement speed of 2 mm / s. The rate of increase in the dynamic friction coefficient when the measurement speed is increased from 2 mm / s to 40 mm / s is 20% or less. A thermosetting topcoat varnish is provided.

  The present invention further includes at least one thermosetting resin selected from the group consisting of a polyester resin, an acrylic resin, an epoxy resin, and a vinyl resin as a binder resin, and the fine powder that is 1 to 20% by weight of the total amount of the paint. The present invention relates to a solvent-based thermosetting topcoat varnish for metal containers.

  The present invention relates to a metal-organic coating laminate in which a solvent-based thermosetting topcoat varnish for a metal container is coated on an upper surface of a ground coating layer or an offset printing layer formed on a metal substrate.

  The present invention further provides an overprint varnish composition for a laminate container film, which further contains at least one thermosetting resin selected from the group consisting of a polyester resin, an epoxy resin, and a vinyl resin as a binder resin, and the fine powder particles. Further, the present invention relates to an overprint varnish for a laminate container film, wherein the content of fine powder particles is 0.5 to 10% by weight of the total amount of the varnish composition.

  The present invention also provides a plastic film laminate formed by applying an overprint varnish for a film laminated metal container to at least one side of the film.

  Metal container varnish and film-laminated metal can container overprint varnish for metal containers that do not interfere with high-speed transport even if irregularities are formed using a filler with a fixed particle size for the purpose of producing an anti-slip effect A solvent-based thermosetting topcoat varnish can be provided.

  The solvent-based thermosetting top varnish for metal containers of the present invention is a thermosetting top varnish containing urethane resin beads having an average particle diameter of 6 to 110 μm, and is 0 when the measurement speed is 2 mm / s. Of the dynamic friction coefficient when the measurement speed is increased from 2 mm / s to 40 mm / s. It is essential that the rate of increase is 20% or less.

  The urethane resin beads used in the present invention preferably have an average particle diameter in the range of 6 to 110 μm, more preferably in the range of 30 to 80 μm. When the average particle diameter is less than 6 μm, the surface unevenness of the coating film becomes small, and the anti-slip effect when contacted becomes low. Further, when the average particle diameter exceeds 110 μm, since the surface unevenness is too large, the rate of increase in the dynamic friction coefficient value becomes high, which may hinder the transportability during high-speed production.

  The glass transition point of the urethane resin beads is preferably in the range of −80 to −10 ° C., more preferably in the range of −60 to −30 ° C. If the glass transition point is below -80 ° C, the possibility of wicket marks is increased when baking the metal plate at a high temperature, and if it is higher than -30 ° C, the soft tactile sensation on the surface of the coating film is impaired. The anti-slip effect tends to be low.

  Moreover, it is preferable that the addition amount of a urethane resin bead is 1-20 weight% of a coating material whole quantity, More preferably, it is the range of 7-13 weight%. When the addition amount is less than 1% by weight of the total amount of the paint, the surface unevenness is reduced because the amount of the resin beads present on the surface of the coating film is reduced, and the anti-slip effect when contacted is reduced. Even when the amount is more than 20% by weight of the total amount of paint, the amount of resin beads present on the surface of the coating film is excessive, so the surface unevenness is eliminated because the gap between the coating film and the resin beads is filled. Becomes lower.

  The resin for the solvent-based thermosetting topcoat varnish for the metal container used in the present invention may be at least one resin selected from polyester resins, acrylic resins, epoxy resins, and vinyl resins, and other resins are used. In some cases, the resin beads do not float and orient on the surface of the coating film, and surface irregularities may not be formed.

  The solvent-based thermosetting top varnish for metal containers used in the present invention is effective in both forms as a base coat layer formed on a metal substrate or as a metal-organic coating laminate coated on top of an offset printing layer. Is expressed.

  In addition, as a resin when this is used as an overprint varnish for a film for a laminate container, at least any one resin selected from a polyester resin, an epoxy resin, and a vinyl resin may be used, and when a resin other than these is used. In some cases, surface irregularities may not be formed for the same reason as described above. The overprint varnish of the film for a laminate container has a limitation on the heating temperature because the film deteriorates, and the kind of resin that can be used is also limited.

  The diluting solvent that can be used in the present invention is not particularly limited. For example, aromatic hydrocarbons such as toluene, xylene, Solvesso # 100, Solvesso # 150, and aliphatic hydrocarbons such as hexane, heptane, octane, and decane. And various ester organic solvents such as methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, amyl acetate, ethyl formate, and butyl propionate. Water-miscible organic solvents such as alcohols such as methanol, ethanol, propanol, and butanol, ketones such as acetone, methyl ethyl ketone, and cyclohaxanone, ethylene glycol (mono, di) methyl ether, ethylene glycol (mono, di) ethyl ether, ethylene Glycol monopropyl ether, ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol (mono, di) methyl ether, diethylene glycol (mono, di) ethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol (mono, di) methyl Ether, propylene glycol (mono, di) methyl ether, propylene glycol monopropyl ether , Propylene glycol monobutyl ether, dipropylene glycol (mono, di) include various organic solvents glycol ether such as methyl ether. Of these, it is usually preferable to use methyl ethyl ketone, ethyl acetate, or a mixture thereof.

  A lubricant, an antifoaming agent, a leveling agent, a pigment and the like can be appropriately added to the solvent-based thermosetting topcoat varnish for a metal container of the present invention as necessary. In addition, other curing agents such as urea resin, melamine resin, benzoguanamine resin, isocyanate resin, and phenol resin may be used in combination as curing aids, and these are dried in the case of paint baking conditions or film coating. Appropriate materials can be used in combination depending on the conditions and lamination conditions.

The solvent-based thermosetting top coat varnish for metal containers of the present invention is prepared by various means such as air spray, airless spray or electrostatic spray, by various means such as spray coating, dip coating, roll coater coating, gravure coater and electrodeposition coating. It can be applied to metal substrates such as steel plates and aluminum plates, PET pet films and the like. The coating amount is preferably about 0.1 to 20 μm in terms of dry coating thickness. As the coating amount of the present composition, in the case of a coating applied directly to a metal substrate, the solid content is 1 to 15 g / m ² , preferably 5 to 10 g / m ² . When used as an overprint varnish for a film, it is used at a coating condition of 0.5 to 5 g / m ² , preferably 1 to 3 g / m ² .
When the coating amount is less than the above range, it is difficult to produce continuous uniform coating properties, and it is somewhat difficult to develop physical properties and design properties. On the other hand, when the coating amount is larger than the above range, the solvent detachability after coating is lowered, the workability is remarkably lowered and the problem of residual solvent is likely to occur. And the blocking property at the time of winding the film may be significantly reduced.

  Moreover, it is preferable that the solvent-based thermosetting topcoat varnish for a metal container of the present invention is baked within a range of 100 to 280 ° C. and 1 second to 30 minutes. When it is applied to a film substrate such as PET or PP, it is dried at 80 to 180 ° C. for 1 to 30 seconds and then laminated to a metal plate at a temperature within the range of 150 to 300 ° C. If it is, the outstanding performance as an overcoat varnish can be exhibited.

In the case of direct coating on a metal steel plate and in the case of coating and laminating on a film, the steel plate used is a sheet-like or coiled steel plate, steel foil, iron foil, surface treatment on the steel plate. What you gave. An aluminum plate can be used in addition to the steel plate. In particular, an electrolytic chromic acid-treated steel sheet having an upper layer of chromium hydrated oxide and a lower layer of metallic chromium, ultrathin tin plating, nickel plated steel sheet, galvanized steel sheet, chromium hydrated oxide coated steel sheet or phosphate Examples thereof include steel plates treated with chromate.
When a film is used, the plastic film is not particularly limited, but can be used for a pet film, a polyethylene film, a polypropylene film, a polyvinyl chloride film, and an acrylic film.

  Hereinafter, the present invention will be specifically described with reference to Examples. In the examples, “parts” and “%” represent “parts by weight” and “% by weight”, respectively.

The following raw materials were blended at the ratios shown in Tables 1 and 2 (the numbers in the tables indicate the solid content weight ratio), and stirred with a dispersion stirrer: 3,000 rpm, time: 3 minutes, Examples 1 to 11 And the varnish sample of Comparative Examples 1-7 was produced.

(A) Polyester resin: Byron manufactured by Toyobo Co., Ltd. (B) Acrylic resin: ACDICIC (C) epoxy resin manufactured by DIC Corporation: Epicron (D) vinyl resin manufactured by DIC Corporation: Solvine (E) butyral resin manufactured by Shin-Etsu Chemical Co., Ltd. : Sekisui Chemical Co., Ltd. ESREC (F) benzoguanamine resin: DIC Corporation Super Becamine (G) resin beads: Negami Kogyo Co., Ltd. Art Pearl (H) wax: Clariant Co., Ltd. Celidust (I) Solvent: Xylene / Butyl Cellosolve = 1 / 1 (weight ratio)

[Production of test panel]
(1) Paints for metallic steel plates Examples 1 to 6 and Comparative Examples 1 to 5 are applied to a bar coater so that the amount of dry coating is 7 g / m ² on a metal plate (tinplate). It was coated and baked at 190 ° C./10 minutes, and then evaluated.
(2) Overprint varnish for laminate container film In a bar coater, the varnish of the mixing ratio shown in Examples 7 to 11 and Comparative Examples 6 to 7 is applied to a pet film so that the dry coating amount is 2 g / m ² . Apply, dry at 120 ° C for 5 seconds, apply the adhesive for film laminate can on the back surface with a bar coater so that the dry coating amount is 5 g / m ² , and dry at 120 ° C for 5 seconds to apply A film was obtained.
This film was laminated on a metal plate (tinplate) at 190 ° C.-100 m / min, and then baked at 220 ° C./2 minutes for evaluation.

[Measurement test method]
(Measurement of dynamic friction coefficient)
The dynamic friction coefficient value conforms to ASTM D1894-90 (test conditions for measuring the friction coefficient of plastic films and sheets when sliding on the same material or other materials), and is a TA. XT. Measurement was performed using Plus.
The contact surface is 63.5 mm x 63.5 mm, the load is 200 g, the surface material is A. felt ground (equipment standard) and B. rubber gloves, and the pulling speed is 2 mm / s and 40 mm / s. Two points were done.
The calculation method of the rate of increase in the dynamic friction coefficient was a dynamic friction coefficient of 100 × (value at 40 mm / s measurement−value at 2 mm / s measurement) / 2 mm / hour.

[Evaluation test method]
(Evaluation item 1: feel (non-slip feeling))
For the evaluation of the anti-slip feeling, a sample in which the metal plate created above was wound around the side surface of a coffee can-like container and a commercially available can were touched by 20 subjects with hands and fingers, and compared with a commercially available can I asked them to answer the following five grades in a questionnaire format, and adopted the average of the totals. A score of 4 or more was considered to have an anti-slip effect.

5: Very slippery compared to commercial cans 4: Slippery compared to commercial cans 3: No change compared to commercial cans 2: Slippery compared to commercial cans 1: Compared to commercial cans Very slippery

(Evaluation item 2: High-speed transportability)
For the evaluation of high-speed transportability, the metal plate prepared above was wound around the side surface of a coffee can-like container, and the dynamic friction coefficient value of the surface when the sample was brought into contact with each other at high speed was measured. The pulling speed (measurement speed) at this time was 40 mm / s, and the lower the dynamic friction coefficient value, the more advantageous. In addition, it was judged that there was no problem in high-speed transportability when the score was ○ or more.

A: Dynamic friction coefficient value is 0.10 or less B: Dynamic friction coefficient value is 0.11-0.15
Δ: Dynamic friction coefficient value is 0.15 to 0.20
×: Dynamic friction coefficient value is 0.21 or more

Tables 1 to 3 show the evaluation results and the mixing ratio of the samples.
Table 1 shows an example of a panel prepared as a coating for a metal steel sheet.
Table 2 shows examples of panels produced as overprint varnishes for laminate films.
Table 3 shows a comparative example of each of the paint for metal steel sheet and the overprint varnish for laminate film.
In addition, the numerical value in a table | surface shows solid content weight ratio.
Moreover, the average particle diameter of each urethane resin bead was measured using Hitachi's most recent operation type electron microscope S-3400N.

  In the examples, it is shown that both the anti-slip effect by touch and the high-speed transportability when filling the contents can be maintained. In the comparative example, either the anti-slip effect due to the touch or the high-speed transportability when filling the contents was not satisfactory.

  The metal container varnish of the present invention exhibits a high anti-slip effect when it is held in a human hand, so that various soft drink cans such as fruit juice and carbonated drinks, alcoholic beverage cans such as beer and Chuhai, coffee and tea, etc. It can be widely deployed in a wide range of uses such as cans used for heating.

Claims (5)

  It is a thermosetting topcoat varnish containing urethane resin beads having an average particle diameter of 6 to 110 μm, and the dynamic friction coefficient value on the cured coating film surface after heating is 0.2 to 0.2 when the measurement speed is 2 mm / s. Solvent-based thermosetting topcoat varnish for metal containers, characterized in that the rate of increase of the dynamic friction coefficient is 20% or less when the measurement speed is increased from 2 mm / s to 40 mm / s in the range of 1.0 . The binder resin contains at least one thermosetting resin selected from the group consisting of a polyester resin, an acrylic resin, an epoxy resin, and a vinyl resin, and the fine powder that is 1 to 20% by weight of the total amount of the paint. 2. A solvent-based thermosetting topcoat varnish for metal containers according to 1.
A metal-organic coating laminate in which the solvent-based thermosetting topcoat varnish for a metal container according to claim 1 or 2 is coated on an upper surface of a ground coating layer or an offset printing layer formed on a metal substrate.
An overprint varnish composition for a laminate container film, comprising at least one thermosetting resin selected from the group consisting of a polyester resin, an epoxy resin, and a vinyl resin as a binder resin, and the fine powder particles, The overprint varnish for a laminate container film, wherein the content of the varnish is 0.5 to 10% by weight of the total amount of the varnish composition.
A plastic film laminate formed by applying the overprint varnish for a film-laminated metal container according to claim 4 on at least one side of the film.