JPS5811659A - Vessel cover made of metal, inner surface thereof is coated - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is characterized by the fact that when the abnormal increase in the opening torque caused by the formation of cigar cement (KfP) is suppressed, the occurrence of dusting from the paint film is also suppressed to a low level. This invention relates to aiIII metal container lid.

Conventionally, the skirt part of the container lid engaged with the bottle opening screw,
For metal container lids that are opened by the rotation of the cap, the cap resistance is considered to be the same as that determined by the friction between the lip of the bottle opening, the sealing material, and the friction. .

However, in the case of bottled coagulated sugar-containing liquid contents such as soft drinks, the inventors have found that an abnormal increase in running torque often occurs during storage. As a result of intense research and insight into this unusual rise in jH&), we have found a place where the screw of the bottle opening and the skirt of the container lid firmly connect them to each other. We found that the reason for this is the formation of

In other words, when manufacturing bottled products, the sugar-containing contents may drip from the filler into the threaded part of the bottle opening, and carbonated beverages often cause the contents to blow out during filling. ), the contents adhere to the threaded part of the bottle opening, and the lid of the container is sealed by rolling on until this point i, which is the cause of sugar cement formation.

The present inventors have developed an II material containing a high molecular weight polyolefin on the innermost surface side of the container lid skirt portion that engages with the screw of the bottle opening.
According to the present invention, it has been discovered that by providing a coating film containing a high molecular weight polyolefin, an abnormal increase in running torque can be suppressed despite the formation of such sugar cement. In the sense that it acts to suppress the abnormal increase in service torque due to the formation of sugar cement without reducing the overall quality of the product, this coating film also acts to suppress the abnormal increase in service torque due to the formation of sugar cement. This method is extremely different from the object of the present invention in that dusting, that is, the occurrence of flakes peeled off from the coating film, can be suppressed to a negligible level.

Therefore, it is an object of the present invention to maintain a sufficient level of service torque to maintain the sealing of bottled products, and to prevent an abnormal increase in service torque due to shegger cement formed in the threaded portion of bottle bottles. To provide an internally coated metal container lid which exhibits a remarkable suppressive effect and also significantly suppresses the occurrence of dusting.

Another object of the present invention is to suppress the above-mentioned abnormal increase in lH & To provide container roofing.

Still another object of the present invention is to significantly improve the dispersion of high molecular weight polyethylene into the paint, which acts to suppress abnormal increases in service torque due to the formation of Sieger cement, and to prevent the occurrence of dusting from the paint film. There is a method for providing a container lid made of metal with an inner surface coated which is more effectively suppressed.

Still another object of the present invention is to ensure that the coating film applied to the innermost part of the container lid exhibits an action as a protective coating film for the metal substrate and an adhesive action for the sealing material made of thermoplastic resin. The present invention aims to provide an inner-coated metal container lid in which the coating film exposed on the inner surface of the bottle bottom skirt has a remarkable effect of suppressing an abnormal increase in opening torque due to the formation of sugar cement.

Zero shot 11! According to the method, the top plate has a top plate and a skirt that hangs down from the periphery of the carcass top plate, and the inner surface 11 of the top plate is provided with a sealing material, and the skirt engages with a screw on the container mouth to rotate the container.
In a metal container lid structured to be opened by 1,
The innermost surface of the skirt, which engages with the screw at the container opening, is coated with a coating containing polyolefin having a number average molecular weight of 10,190 to 100,000. A container lid is provided.

According to the present invention, furthermore, 1 in the metal container lid, the innermost surface of the skirt that engages with the screw of the container opening contains a polyolefin having a number average molecular weight of 10,100 to 100,000 and an oxidized polyethylene or acid-modified olefin resin. Provided is an easily openable internally coated metal container lid characterized by being provided with a coating film containing the following.

The present invention will be explained in detail below.

In No. 111, which shows one example of the container lid of the present invention, the container lid shown as 1 as a whole consists of a top plate part 2 and a skirt part 3 hanging down from the periphery thereof. As is clear from the section No. 111, this container lid 1 is made of a metal substrate 4 of, for example, a surface-treated steel plate and an aluminum cape, and at least the inner surface is coated with primer coatings 5g and 5k. It has been subjected. The inside of the top plate part 20 is coated with a primer coating 5.
A sealing material 6 is provided through 1. Skirt part δO
The upper part is provided with a knurled groove 7 for easy handling, while the lower part is filled with bottles. an omniscient pilfer-proof mechanism, which ensures that no
For example, 2 syn@8 is engraved. .

This container lid 1 has a bottle 90 lip 10 on top of the bottle opening 9.
Although not shown, the skirt portion 6 is machined along the screw 11 of the bottle opening 9, and the jaw 121C of the bottle opening is By bending the lower end of the skirt portion 6 inward along the same line, the bottle rotor is completely sealed.

According to the present invention, the coating film 5 located in the skirt portion 60 portion
A is formed from a paint containing a high molecular weight polyolefin, and the high molecular weight polyolefin-containing paint film is positioned on the innermost side of the skirt portion 6 that engages with the screw 11 of the bottle opening 9 [111riL]. This high molecular weight polyolefin stands out on the surface of the coating (115 g), and is formed at the junction between the inner surface of the skirt portion 6 and the bottle opening screw 11 (7).
It is recognized that this provides a crushable or easily slippery interface to K (not shown) and suppresses abnormal increases in R&torque.

In the present invention, the inclusion of a high molecular weight polyolefin in the innermost coating film 5α of the skirt portion provides extremely significant advantages. ``Conventionally, it has been known that polar waxes such as various animal and plant waxes and non-polar waxes such as chlorine wax are used as lubricants.
Ru. However, when these wax-based lubricants are included in the protective coating on the container lid skirt, the abnormal increase in the operating torque of Jugar cement can be suppressed to a certain extent. However, it was found that a fatal defect occurred in terms of dusting generation. That is, the container lid is formed by punching a painted metal plate using a press and drawing it into a cap-shaped body.During this drawing 9 forming, the punch surface [11! The wax in II peels off and migrates, which becomes dust and adheres to the lid of the container, and in more severe cases, the wax adhering to the surface of the punch makes accurate drawing forming difficult.

ξ, according to the invention, the number average molecular weight is 10.1
When K contains a polyolefin of 0.00 to 100,000, as mentioned above, the abnormal increase in opening torque is significantly suppressed, and the tendency of polyolefin to transfer to processing tools such as punches is completely suppressed, resulting in less dusting. This makes it possible to set the level to 11h by ignoring the occurrence of .

In addition, when a lubricant made of the waxes mentioned above is contained in a coating film, the desired effect of suppressing the increase in opening torque cannot be obtained unless it is mixed in a large amount of kana sand. According to K, by using a high molecular weight polyolefin, the same effect of suppressing the increase in the opening torque can be obtained with a relatively small amount of blending.

The reason for this is that while waxes tend to be compatible to varying degrees in the coating film, the high molecular weight polyolefin used in the present invention oozes out onto the coating film surface and creates a slippery interface or This is thought to be due to the strong tendency of forming a nonpolar interface.

In the present invention, the high molecular weight polyolefin includes low density, medium density or high density polyethylene, isotactic polypropylene, crystalline ethylene-propylene copolymer, crystalline ethylene-propylene-butene-1 copolymer, or These polymer pre-nods having a length of 2s or more are used.

As the polyolefin, any number of copolymers containing a small amount of monomers other than olefins may be used as long as the essence thereof is not impaired.The number average molecular weight of these polyolefins is 10,100 to 10α000, especially 14,00
The fact that there is a range of 0 to 5 CLO00o is also a superposition,
When this molecular weight is lower than the above range, K has a strong tendency to cause dusting, and when it is larger than the above range, the m* forming ability decreases, which tends to result in poor casting properties.

According to the present invention, the above-mentioned polyolefin is blended in an amount of 100 parts by weight to 301 parts by weight, preferably 5 to 20 parts by weight, as solids in the coating film.

That is, if the amount of polyolefin blended is lower than the above range, it may be difficult to suppress the abnormal increase in the -elm torque over a long period of time, whereas if it exceeds the above range, the smoothness of the coating film may deteriorate. Damage 9D, II! There is a tendency for the corrosion resistance, compactness or adhesion of the membrane to the seal to be impaired.

In the present invention, 1 in the paint containing polyolefin
As the base resin for forming blinds, any thermosetting or thermoplastic paste resin for coating film formation conventionally used in this field can be used. Suitable examples of such base resins are phenolic resins, although not specified in this book.
Formaldehyde resin, xylene-formaldehyde I
N, melamine formaldehyde resin, urea formaldehyde resin, epoxy resin, alkyd resin, thermosetting polyester resin, oleoresinous resin, polyimide resin, thermoplastic polyester resin, polyamide resin,
Acrylic resin, vinyl chloride resin, vinyl chloride-vinyl acetate resin, vinyl chloride-vinyl acetate-maleic acid resin m+,
Vinyl butyral resin, polyolefin resin, etc. may be used alone or in combination of two or more.

In addition to the film-forming base resin, these coatings contain additives known per se, such as adhesion promoters, tackifiers,
Rust inhibitors, viscosity modifiers, leveling agents, ultraviolet absorbers, heat stabilizers, antioxidants, and the like can be blended according to known formulations.

When preparing a paint, the above-mentioned nine film-forming base resins are mixed with an aromatic solvent such as toluene, a ketone solvent such as acetone or cyclohexanone, an ester solvent such as ethyl acetate, or a cellosolve solvent such as butyl + Rosolp. The polyolefin is dissolved in a single solvent or a combination of two or more of them, and the polyolefin is atomized and dispersed in this solution. This polyolefin can also be mechanically dispersed in a Kmm bath solution, but by taking advantage of the property of this polyolefin being easily dispersible in hot toluene etc., a hot toluene solution of the polyolefin is added to the paint solution to form a coating film. It is possible to produce a coating material in which a polyolefin is atomized and dispersed in emulsion size in a solution of a paste resin. The nine paints S* manufactured in this way have excellent painting workability and are also highly effective in suppressing abnormal increases in opening torque.The total solids concentration in the paint is 10 to 50% Category 1! IK is desirable from the point of view of workability.

According to the most preferred embodiment of the present invention, in addition to the above-mentioned high molecular weight polyolefin, the coating film on the innermost side of the skirt portion includes:
Oxidized polyethylene or acid-modified olefin resin is blended.

That is, the oxidized polyethylene-modified olefin resin significantly improves the dispersibility in the high-molecular-weight polyolein oil material, and further acts to further improve the dusting resistance of the formed coating film, Thus, according to this preferred MS of the present invention, a metal container with an inner surface coated which has the best combination of ease of opening, toughness, dust resistance, and corrosion resistance,
It becomes possible to provide the product with good workability.

In this ms of the present invention, the oxidized polyethylene/polyethylene is obtained by oxidizing polyethylene or a copolymer mainly composed of ethylene in a melt or solution state as desired. A polymer containing a polymer concentration of 60 to 60 Qmg/100 is used.

In addition, as the acid-modified olefin resin, the above-mentioned nine polyolefins are converted into the following monomers (1) Ethylenically unsaturated carbon fa = acrylic acid, methacrylic acid, i, inic acid, hexamaric acid, crotonic acid, itacon acid, citraconic acid, 5-norbornene-2,
3-dicarboxylic acid, (2) ethylene, / unsaturated carbon anhydride a: anhydride i
Leic acid, citracone acid anhydride, 5-norbornene-2
, 3-dicarboxylic acid anhydride, tetrahydro-7-talic anhydride, modified with at least 1 s, and containing carboxylic acid groups at the above-mentioned concentration.

In the preferred embodiment, the high molecular weight polyolefin is used in the amounts described above, while the oxidized polyethylene or acid-modified olefin resin is used in amounts up to 100 parts by weight. α is used in an amount of 2 to 40 parts by weight, and 5 to 91 parts by weight.

l! If the blending amount of the polyolefin tree is less than the above range, a satisfactory effect of improving the polyolefin dispersibility cannot be obtained, whereas if it is larger than the above range, the effect of suppressing the increase in torque abnormality may not be obtained. tends to be deoxidized.

The above-mentioned modified olefin! III. It is also desirable to prepare a hot toluene dispersion with the polyolefin and add this to the paint.

In the present invention, the above-mentioned polyolefin-containing coating film 5a
is the inside of the skirt portion 3 of the waste container lid 1 shown in FIG.
You may provide only -, but the 21st! As shown in llK, it may be provided as a coating film 5 over the innermost face of the J container lid 1.

To manufacture the container lid of the present invention, the polyolefin-containing paint described above is applied to the surface of the metal substrate for forming the container lid, which is to become the inner surface of the cap, and then baked.

The metal base for forming container lids generally has a thickness of 0.1 mm.
0~MO, 70wn5, special K (L '15~0.
Various metal plates in the range of 55 wm are used. Such metal plates include various surface-treated steel plates, such as chemical treatments such as phosphoric acid treatment and chromium treatment, electrolytic treatments such as electrolytic chromic acid treatment, electrolytic tin plating, and electrolytic chrome plating;
At least one cape treated with hot-dip plating such as hot-dip tin plating
Preferably used are a steel plate with a steel surface coated with aluminum, a cold steel plate (plaque plate) with no special surface treatment, or a grooved metal plate made of aluminum or aluminum alloy.

A metal plate that can be used particularly suitably for many purposes has an amount of tin plating on the inner and outer surfaces, respectively, in the range of #10 to #150, especially #2.
Range I from 5 to #100! At least one coating layer selected from the group consisting of a tin-plated steel plate, a metallic chromium layer, and a non-metallic chromium layer is α80-i in terms of metallic chromium,
5Qsy+/j,/, especially α90 to tflOWII/
Ting Fist 7 prepared with the amount of d- Lee Su f-k (115
)@, aluminum or its alloy plate.

When it comes to applying a coating film to the surface of a metal substrate, the surface of the metal substrate must be coated! After detumescence and cleaning by means known per se, it is coated with a coating method known per se, such as dip coating, spray coating, eyelid coating, electrostatic coating, etc. in an OqP stage.

Prior to providing a polyolefin-containing coating film, if desired, a coating similar to the above except that it does not contain polyolefin may be applied as an undercoat to the metal substrate. General <10 to 500 k/d-1 Especially 30 to 100 k/d
It is best to apply with a coating amount of -.

The baking of paint differs depending on the type of paint.
General vc 120 to 500 C (DJLl ['3 to 20 minutes is recommended.

This coated metal sheet is then stamped, pressed or drawn into a disc by means known per se, for example into a cup shape (formed in the shape of a cup) and necessarily curled, knurled or perforated. , perform thread cutting, etc. to form a container lid shell.

The sealing material can be formed into the shape of the desired backing outside the container lid and applied to the container lid@VC, but preferably, thermoplastic resin is extruded inside the container lid shell and pressed into the shape of the sealing material. Molding and thermal bonding are performed to form the seal in situ. t
In the case of plastisol, the sol is applied inside the container lid shell, formed into the desired sealant shape by centrifugal molding, and then gelled by heat to form the desired sealant.

Thermoplastic resins for sealing materials have appropriate ductility properties, and olefinic resins such as polyethylene, polypropylene, ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, etc. are suitable for melt-molding. Mention may be made of 111 or a combination of two or more of the following: polymers, ethylene-acrylic-ester copolymers, iono-i-misaki; IIIK advantageous ones include low-density polyethylene,
It is an ethylene copolymer, etc., and has the following properties as a sealant:
Low-density polyethylene, (b) ethylene-monopyrene copolymer, and (thermoplastic elas) ff-1% at least 41s of styrene-diene (butadiene or isoprene)-styrene polypyrene copolymer. It is desirable to use a composition that is a blend of low-density polyethylene, and these modifying components are preferably contained in an amount of 5 to 40 g of low-density polyethylene.

The paint containing the above-mentioned polyolefin and a-modified olefin resin exhibits binding specific heat adhesion to the olefin resin sealant, and is extremely advantageous in this respect as well.

Another interesting example of a thermoplastic resin for a sealant is a soft vinyl chloride resin which is applied to the inner surface of a container lid (in the form of plastisol or by melt molding).

Coatings that exhibit good adhesion to soft vinyl chloride resins are those that use vinyl chloride resins such as vinyl chloride-vinyl acetate copolymers, acrylic resins, resins, etc. as film-forming base resins. be.

In the present invention, the m section located at the innermost surface of the skirt part of the container exhibits a characteristic ape property not found in this type of container lid, that is, - For example, only the mg-forming base resin The IIIj[interface] generally exhibits a water drop contact angle (23c) smaller than 180 degrees;
In contrast, ma according to the present invention exhibits a water droplet contact angle of 100 degrees or more, whereas the degree is small and exhibits a water droplet contact angle of 80 degrees or more. Although it is a smooth 111M, it is characterized by a high degree of hydrophobicity or non-polarity.This is because the polyolefin stands out during baking of the coating and forms a thin film. It is thought that this polyolefin thin layer is firmly anchored to the coating film-forming base resin.

mW! 4.

In this example, ordinary vinyl paint was applied to both sides of an aluminum building board for a cap with a thickness of 0.23 wm and baked. Polyethylene solution with a molecular weight of 18,000o (hot xylene solution 2)
A sample solution was prepared by adding 10 parts by weight of polyethylene to 100 parts by weight of the solid content of the base resin.

Next, various sample solutions were applied to one side of the Al ζ plate coated with the above-mentioned vinyl paint on each side of If (the inner surface of the cap) so that the dry coating amount was 50111/jj. Various double-sided coated plates were prepared by baking at 200C for 10 minutes. As a comparative example, plates coated with various resin paints without the addition of polyethylene were also prepared in the same six operations.

These painted plates are processed by normal cap forming process (pressing and
By doing thin 1 processing etc.), the outer diameter is 28■ and the height is 18■
The pill 7-a-proof shoe cap (PP cap) is molded into a shell.

A foamed polyethylene gasket (outer diameter: 2 x 5 x thickness: 2 x) was inserted as a sealing material into the inner top plate of the resulting middle cap to create a PP cap. These caps are filled with the contents of sugar content, commonly known as 28 PP caps, and are screwed onto the 6th part of a bottle with a screw-on mouth using a roll-on method. After storing it for 3 months, the opening torque was measured.

The results are summarized in Table 1K.

For evaluation, measurements were made under two conditions: (1) with 71 bottles of the contents α1 attached to the bottle mouth and (2) with a clean bottle mouth. In addition, the results of measuring the water droplet contact angle of *H on the inner surface side of each coated plate are also listed.

In the case of conditions in which the contents adhered to the bottle mouth, the comparative torque values of all samples increased compared to the conditions in which the contents did not adhere, but in the case of the polyethylene-added type according to the present invention,
Compared to other samples, the effect of suppressing the increase in torque was demonstrated. In addition, a correlation was given between torque value and contact angle.

Example'2 For a paint such as epoxy phenol resin containing 20% polyethylene oxide, 1% polyethylene having a different average common molecular weight was added in the same manner as in Example 1. -2 to prepare a sample solution.

Next, one IIK of the aluminum cap plate having a thickness of α25− coated with vinyl paint on both sides, and the various samples IIt mentioned above were applied separately so that the dry coating amount was 5Qq/d−,
Each plate was baked at 200G for 10 minutes, and the coated plates were then subjected to normal cap forming processing (pressing, perforation, etc.) so that the ms side of each sample solution was on the inside. A Bilfer Proof 11 cap (PP cap) shell with a height of 18 cm was molded.

A PP cap was created by extruding hazardous polyethylene by heating and melting the inner top plate of the JP cap shell, and then wet-pressing and bonding a polyethylene liner to the inside.

These caps were filled with inner spring with a sugar content of 1091, and were stored under the same conditions as in Example 1 for the same period of time with the threaded H1tk tightened by a roll-on method to the mouth of a bottle with a threaded bottle bottle for food commonly known as 38-kaku PP caps. Rear torque was measured.

In addition, the measurement of the droplet contact angle on the coated plate side as in Example 1, the moldability during cap molding, and the liner adhesion were also evaluated. The results are summarized in Table 2.

In the evaluation of the opening torque, 71 bottles of the contents α2-7 were attached to 0270 parts, and measurements were made under two conditions: one with a clean bottle mouth and one with a clean bottle mouth. The effect of suppressing the increase in torque was remarkable in the case of polyethylene added.In the sample coated plate to which polyethylene having a small average molecular weight was added, peeling of the coating film was somewhat noticeable during the molding of the lubricant.

Example 5 A regular vinyl layer was applied on both sides of an aluminum plate for a cap with a thickness of 23 sheets.
Apply and bake the paint. Next, using the paint of sample *6 used in Example 2, the piece El of the vinyl paint-coated board mentioned above was painted.
Apply amount 50sz/ltW to i (the inner side of the cap) excluding the top plate part when forming the cap?
It was spotted and baked at 200C for 10 minutes. The obtained coated plate was molded into a cap in the same manner as in Example 2 (however, the portion where the sample coating was not formed was precisely arranged to form the top plate) to form a pill 7 ear loop type cap shell. Molded.

The inner top plate of the resulting T-cap shell was lined with an ordinary plastisol type vinyl chloride compound, and heated to gel to produce a cap shell having a vinyl chloride resin liner on the inner surface. These caps were subjected to constant running torque evaluation in the same manner as in Example 2 with and without sugar cement.

Incidentally, the cap shell of Sample 6 used in Example 2 was lined with vinyl chloride sol, and the same evaluation was conducted using t4 as a comparative example. The results are shown in Table 5VC.

The red color of the present example and the comparative example showed an excellent effect of suppressing the increase in torque. However, in the cap of Comparative Example, the liner had poor adhesion and often fell off from the cap shell.

Table-6

[Brief explanation of drawings]

Figures 1 and 2 are partial cross-sectional side views showing an example of the container lid of the present invention 1 together with the bottle opening, where the side reference numeral 1 is the container lid, 2 is the top plate, 3 is the skirt, and 4 is the side view.
1 is a metal substrate, s and sj are polyolein-containing coatings, 6 is a sealing material, 9 is a bottle opening, 1o is a lip portion, and 11 is a screw. Patent applicant Nippon Crown Cork Co., Ltd. Figure 1

Claims (6)

[Claims] (1) It has a top plate part and a skirt part lowered from the periphery of the top plate part, and a sealing material is provided on the inner surface of the top plate part, and the skirt part engages with the screw of the sS opening part and is opened from the turning aK. In the metal container 1i having a structure in which this is carried out, the inside of the skirt portion 1N11 that engages with the screw of the container mouth 1g is covered with a coating film containing a polyolefin having a number average molecular weight of IQ of 100 to M10α000. Features include a metal container lid with an opening mechanism. (2) #1eltl [11M110GI amount 1111
A container quantity according to claim 11J1, wherein the 1D H9 olefin is present in an amount of 1 to 130 parts by weight. (3) The container according to claim 1, wherein the coating film has a water droplet contact angle (25C) of 100 degrees or more. (4) In the above-mentioned coating film feature (claim 1), the polyolefin is raised to form a thin film.
VS Fuki on Jffi. (5) It has a top plate part and a skirt part that is lowered from the periphery of the top plate IEIi, and the inside of the top plate part i11mK is equipped with a sealing material, and the skirt part engages with the screw of the container mouth part to allow it to rotate. In a metal container having a structure to be sealed, the inner open side of the skirt portion that engages with the rim of the container opening is made of polyolefin with a number average molecular weight of 10.100 to 100,000 and polyethylene oxide or lI modified olefin resin. An easy-to-open inner surface-coated metal container lid, characterized in that it is provided with a swm* containing . (6) The solid content of the coating film is 100 parts by weight, the polyolefin is present in an amount of 1 to 30 parts by weight, and the saponified polyethylene or acid-modified olefin resin is present in an amount of α2 to 40 parts by weight, respectively. 11! Container quantity.