JPS63231937A - Cover material for sealed package - 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] Leading vehicle! Isu1 group! The present invention relates to a new material useful as a lid material for sealed packaging containers made of glass, ceramic, etc. When the material of the present invention is used as a lid material, it exhibits excellent sealing performance over a long period of time not only for powder products but also for liquid products, and is easy to open and has a beautiful opening.

Prior art and its problems Conventionally, liquid or fluid contents such as alcoholic beverages, juices, dressings, mayonnaise, and jams are mainly contained in glass containers and sealed with metal or plastic screw caps. However, they have the drawbacks of being extremely difficult to open and expensive. Another method is to caulk an aluminum plate to the opening of the glass container and seal it, but this method is also difficult to open and is also expensive. Some glass containers for storing powders such as instant coffee and powdered cream are heat-sealed and sealed using a laminate material such as aluminum foil or paper that has been coated with a heat-sealing agent. When the container is used as a sealed package for a liquid or fluid, there is a drawback that the adhesive strength of the heat-sealed portion decreases significantly within a short period of time due to contact with the contents, resulting in peeling. Japanese Patent Publication No. 53-8278 discloses a technique of heat-sealing a silane compound to the open end surface of a glass container, but this method also has problems. In other words, if the sealant coating thickness is not sufficient, uniform heat sealing will be difficult due to unevenness of the opening of the glass container, variations in the parallel parts, etc. On the other hand, if the coating thickness is made sufficiently large, the cost will be significant. It gets loud. In addition, after filling the contents into a glass container and sealing it, boil sterilization or retort sterilization is performed, but in this case as well, a combination of a glass container and a lid material that can sufficiently withstand high-temperature sterilization is required. The current situation is that it is difficult to obtain. Furthermore, paper, film, adhesive, etc. often remain at the opening of the container after opening, creating an unsightly appearance.

The present inventor has completed a material for a sealed packaging body in which different thermoplastic resin layers are formed on the open end surface of a glass container and the base material for the lid, and has already applied for a patent.

(Japanese Patent Application No. 57-210338 and Patent Application No. 57-210
No. 339). A sealed package made of a combination of a glass container and a lid material has excellent heat-sealing properties, does not show a decrease in adhesive strength even when it comes into contact with liquid contents, is easy to open, and has a It has the excellent effect of making the container opening look beautiful. However, since it requires a step of forming a thermoplastic resin layer on the open end surface of the glass container, there is room for improvement from an economic standpoint.

In view of the above-mentioned problems with the conventional technology, the inventor of the present invention has conducted various studies, and as a result, has developed a method for using a modified polyolefin resin with a specific composition as an undercoat layer, a bonding layer, or as an intermediate W14 layer. It has been discovered that these problems can be substantially eliminated or significantly reduced when using certain composite materials in new configurations. That is, the present invention provides a lid material for a sealed package as shown below: (a) a base material; (b) a thickness mainly composed of a modified polyolefin resin provided on one side of the base material; An undercoat layer of 1 to 10 μm, and (c) a bonding layer of 10 to 100 μm thick made of a polyolefin resin or modified polyolefin resin with excellent adhesion to the undercoat layer provided on the undercoat layer. Features: Lid material for sealed packages (hereinafter referred to as the first invention of the present application); (a) base material; <E)) Thickness mainly composed of modified polyolefin resin provided on one side of the base material an undercoat layer of 1 to 10 μm; (c) an intermediate layer of 10 to 100 μm thick made of a polyolefin resin and/or modified polyolefin resin with excellent adhesion to the undercoat layer provided on the undercoat layer; and (d) ) 100,111 parts of modified polyolefin resin and 0.1 to 20 parts of silane coupling agent provided on the intermediate layer
A lid material for a sealed package characterized by having a topcoat bonding layer having a thickness of 1 to 20 μm consisting of parts by weight (hereinafter referred to as the second invention of the present application); and (a) a base material; (b) An undercoat layer with a thickness of 1 to 10 μm mainly made of a modified polyolefin resin provided on one side of the base material, (c) a polyolefin resin with excellent adhesiveness to the undercoat layer provided on the undercoat layer, and/or Silane is added to 100 parts by weight of a mixed resin consisting of 100 parts by weight of modified polyolefin resin and 10 to 100 parts by weight of epoxy resin provided on the intermediate layer having a thickness of 10 to 100 μm made of a modified polyolefin resin, and (d) the intermediate layer. system coupling agent 0.1
1. A lid material for a sealed package (hereinafter referred to as the third invention of the present application), comprising a topcoat bonding layer having a thickness of 1 to 20 μm and containing 20 parts by weight.

The base materials themselves used in the first, second and third inventions of the present application are the same as those conventionally used as base materials for sealed packages for powder, such as aluminum foil and thin plate, plastic film, paper or Since these laminates etc. can be used,
Although not detailed, specifically, aluminum foil and thin plate,
Examples include polyester film, paper, and laminates thereof.

In the first invention of the present application, the modified polyolefin resin, which is the main component of the resin applied as an undercoat layer with a thickness of 1 to 10 μm on one side of the substrate, is prepared using a conventional method such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, etc. By copolymerizing unsaturated carboxylic acids (maleic acid, fumaric acid, crotonic acid, acrylic acid, methacrylic acid, etc.) or their acid anhydrides (maleic anhydride, itaconic anhydride, etc.) with a polyolefin resin, polyolefins can be produced. It has a carboxyl group introduced. Specifically, ionomers, ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers, carboxylated polyethylene, carboxylated polypropylene, carboxylated ethylene-vinyl acetate copolymers, etc. are exemplified, and one or two of them may be used. More than one species is used.

When used for applications requiring heat resistance such as retort sterilization and boil sterilization, the copolymerization ratio of unsaturated carboxylic acid or its acid anhydride to polypropylene should be such that the acid value of the modified polypropylene is 0.1 to 100. It is preferable to set it to about #F-KOH/9. If the acid value of the modified polypropylene in the undercoat layer is less than 0.1 q-KOH/g, the adhesive strength to the substrate will be low. On the other hand,
If it exceeds 100 jlllF-KOH/g, the adhesive strength to the base material will improve, but the adhesive strength to polypropylene, which may be used in the intermediate layer described below, will decrease, and the resin itself will become too soft. The cohesive force becomes smaller, and the heat resistance also decreases.

As resins mainly composed of modified polyolefin resins,
The modified polyolefin resin may be used alone, and in order to further improve adhesiveness, modified polyolefin resin 10
Polyolefin resins such as polyethylene and polypropylene, vinyl resins, epoxy resins,
One or more types of acrylic resins and polyester resins may be blended up to a maximum amount of 0 parts by weight.

The thickness of the undercoat layer is more preferably about 1 to 4 μm.

Prior to forming the undercoat layer on the base material, the surface of the base material before coating may be pretreated by chemical, electrical, mechanical, or other methods.

The formation of this undercoat layer improves the adhesion between the base material and the bonding layer or intermediate layer described below, and also prevents the film from remaining in the opening of the container when the sealed package is opened. .

In the first invention of the present application, the modified polyolefin resin formed as a bonding layer on the undercoat layer by means of melt extrusion, thermocompression bonding of a film, thermocompression bonding of a coextruded film, etc.
It may be the same as that used as the undercoat layer. This bonding layer has good heat sealability to the container,
It is necessary to have cushioning properties, anti-corrosion properties, etc. Therefore, the thickness needs to be about 10-100 μm, and more preferably 20-50 μm.

In addition, in order to prevent blocking and improve slipperiness of the bonding layer, one or more of polyolefin resins such as polyethylene and polypropylene, vinyl resins, acrylic resins, and polyester resins should be substituted with carboxyl group-containing polyolefin resins. A maximum of about 100 parts by weight may be added to 100 parts by weight of the resin.

The lidding material of the first invention of the present application is produced by applying a solution or emulsion of a resin mainly composed of a modified polyolefin resin onto a base material, drying it to form an undercoat layer, and then hot-melt extrusion or roll coating on the undercoat layer. It can be obtained by forming a bonding layer made of a modified polyolefin resin by thermocompression bonding of a film, thermocompression bonding of a coextruded film, or the like.

The base material in the second invention of the present application and the undercoat layer provided on the base material may be the same as those in the first invention of the present application.

In the second invention of the present application, the intermediate layer formed on the undercoat layer is
It is made of a resin that has excellent adhesive strength with the undercoat layer and the topcoat bonding layer described below. As such resin, m-modified or modified polyolefin resin is used, and specifically, polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ionomer, polypropylene, carboxylated polyethylene, Examples include carboxylated polypropylene, carboxylated ethylene-vinyl acetate copolymer, and the like. These resins may be used alone or in combination of two or more. This intermediate layer is for providing cushioning properties, corrosion resistance, etc., and therefore has a thickness of about 10 to 100 μm, more preferably about 20 to 60 μm. Further, the intermediate layer may be a coextruded film layer of modified polyolefin and unmodified polyolefin.

In the second invention of the present application, an overcoat bonding layer with a thickness of 1 to 20 μm is provided on the intermediate layer, which has excellent adhesiveness to the intermediate layer and containers made of glass, ceramic, etc., and has excellent water resistance. . This top coat bonding layer is composed of a silane coupling agent in a proportion of about 0.1 to 20 parts by weight based on 100 parts by weight of the same modified polyolefin resin as that forming the bonding layer of the first invention of the present application. Examples of silane coupling agents include γ-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyl-tris-β-methoxyethoxysilane, β-3,4-
Epoxycyclohexylethyltrimethoxysilane, γ
-Chloropropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane aminopropyltriethoxysilane, N-β-aminoethoxy-γ-aminopropyltrimethoxysilane Examples include silane. When the amount of the silane coupling agent per 100 parts by weight of the modified polyolefin resin is less than 0.1 parts by weight, the improvement in adhesion to glass or ceramic containers is not significant, whereas when it exceeds 20 parts by weight. In case,
On the contrary, the adhesive force to the container decreases. Since the intermediate layer having a thickness of 10 to 100 μm is provided, a uniform seal can be obtained even if the thickness of the top bonding layer is 20 μm or less. The lower limit of the thickness of the topcoat bonding layer is preferably about 1 μm. It should be noted that polyethylene, etc. may be added for the purpose of preventing blocking of the topcoat bonding layer, etc.
This is similar to the case of the bonding layer in the first invention of the present application. The lid material of the second invention of the present application exhibits particularly excellent water-resistant sealing properties as a lid material for a sealed package containing liquid contents.

The lidding material of the second invention of the present application is prepared by first forming an undercoat layer on the base material in the same manner as in the first invention of the present application, and then coating, hot melt extrusion, thermocompression bonding of the film, and heating of the coextruded film. After forming the intermediate layer by means such as pressure bonding, a solution or emulsion of the resin mixture to form the top bonding layer is applied onto the intermediate layer and dried, or the resin mixture is hot-melt extruded and coated onto the base material. Manufactured by

The base material in the third invention of the present application and the undercoat layer provided on the base material may be the same as those in the first invention of the present application. Further, in the third invention of the present application, the intermediate layer provided on the undercoat layer may be the same as that in the second invention of the present application.

In the third aspect of the present invention, an overcoat bonding layer having a thickness of 1 to 20 μm and having excellent adhesion to the intermediate layer and a container made of glass, ceramic, etc. and having good water resistance is provided on the intermediate layer. This bonding layer consists of 100 parts by weight of a mixed resin prepared by adding 10 to 100 parts by weight of an epoxy resin to 100 parts by weight of the same modified polyolefin resin as that forming the undercoat layer of the first invention of the present application.
It is composed of a mixture in which about 0.1 to 20 parts by weight of a silane coupling agent is further added to the parts by weight. The silane coupling agent may be the same as that used in the top coat bonding layer of the second invention. The epoxy resin is preferably an epoxy resin having a molecular weight of about 400 to 10,000 and containing a so-called epoxy resin curing agent such as amines, polyamides, acid anhydrides, phenol resins, butylated melamine formaldehyde resins, butylated urea formaldehyde resins, and the like.

The epoxy resin is formulated in order to maintain the heat resistance of the seal during heat treatments such as boil sterilization and retort sterilization, and to adjust the adhesion to glass, ceramic, etc. containers.
That is, this is done in order to provide appropriate adhesive strength and improve unsealability. If the amount of epoxy resin is less than 10 parts by weight, almost no effect will be observed, while if it exceeds 100 parts by weight, the adhesion to glass containers, ceramic containers, etc. will decrease. Too much. Note that polyethylene or the like may be added for the purpose of preventing blocking of the bonding layer, as in the case of the bonding layer in the first invention of the present application.

The lid material of the third invention of the present application is also manufactured in the same manner as the lid material of the second invention of the present application.

Note that, if necessary, a printed layer, an overcoat layer, etc. can be provided on the surface of the lid material of the present invention opposite to the base material surface on which the bonding layer is formed, according to a conventional method.

The glass container used in combination with the lid of the present invention may be coated with a metal oxide film in a conventional manner. That is, in the normal glass container manufacturing process, the glass container immediately after leaving the forming station, that is, the high temperature end (h
300-600℃ in a glass container
By spraying a solution of a metal compound such as tin tetrachloride at a certain level, an extremely thin film of a metal compound such as tin oxide is formed into the network structure of the glass, improving the mechanical strength and chemical stability of the glass container. Improving sexuality. According to the research of the present inventor, when the contents of the sealed package are liquid, the presence of such a thin film of metal oxide
It has been found that the water resistance of the adhesive portion between the glass container and the lid material is significantly improved.

When manufacturing a sealed package using the lidding material of the present invention,
In the same manner as in the conventional method, a container made of glass, ceramic, etc. is filled with the contents, a lid material is placed on the end face of the opening of the container, and then heat sealing is performed.

Heat sealing conditions may vary depending on the material, shape and dimensions of the container, the type of lid material, the contents to be filled, etc., but are usually carried out at about 200° C. to 240° C. for about 1 to 2 seconds. As the heating means, known methods such as heating with a hot plate and high frequency induction heating are employed. The sealed package after heat sealing is subjected to high temperature sterilization treatment such as boiling sterilization, retort sterilization, etc., if necessary.

1 bean yu 11 According to the present invention, the following effects are achieved.

(1) It is now possible to heat-seal containers and lids without any pretreatment such as coating resin on the open end of containers made of glass or ceramic.

(2) For powder contents such as instant coffee, furikake, and koshiyo, a sealed package exhibiting good performance can be obtained by using the lid material of the first invention of the present application.

(3) When using the lid materials of the second and third inventions of the present application, the water resistance of the sealing portion is particularly good, so that the sealed packaging containing liquids and fluids can maintain the quality of the contents for a long time. hold stable. Furthermore, in the case of the lid material according to the second and third inventions of the present application in which the intermediate layer is provided, uniform sealing is possible even if there are irregularities or the like on the opening end surface of the container.

(4) When using the lid materials of the second and third inventions of the present application, the seal formed between the container and the lid material has excellent heat resistance, so the sealed package can be sterilized by boiling. It can be easily subjected to high temperature sterilization treatment such as retort sterilization.

(5) The fit between the base material and the bonding layer (in the case of the first invention of the present application) and the fit between the base material, the intermediate layer, and the top coating bonding layer (the case of the second invention of the present application)
In the case of the invention and the third invention), the bonding force is very high, so when the sealed package is opened, breakage occurs at the interface between the container and the bonding layer on the lid side, and the container is easily opened. The appearance of the opening is smooth and beautiful.

! -JIJi Examples and comparative examples are shown below to further clarify the characteristics of the present invention.

Example 1 A liquid in which an ethylene-acrylic acid copolymer (referred to as FAA) having an acrylic acid content of 20% was dispersed in aqueous ammonia was prepared as an undercoat.

On the other hand, after mixing the same FAA dispersion as above and the ionomer at a solid content weight ratio of 1:1, γ-glycidoxypropyltrimethoxysilane was added to 100 parts by weight of the solid content in this mixed solution. 2.5 parts by weight was added to prepare a bonding agent liquid.

Thickness 50μ with printing layer and overcoat layer on one side
Apply 1~2a of the above primer to the other side of the aluminum foil
/ff1 (as solid content) and dried at 180° C. for 15 seconds. Next, a 40 μm thick FAA film was pressed onto it using a hot roll. Furthermore, the E
The lid material of the present invention was obtained by applying the above bonding agent liquid onto the AA film at a rate of 3 to 5 Q/d (as solid content) and drying at 180° C. for 15 seconds.

On the other hand, after pouring hot water at 90°C into a glass container, the container was heat-sealed at 230°C x 4 times for 9/C1 x 2 seconds using the lid material.

When the thus obtained sealed package was left in an inverted position at room temperature for 3 months, no water leakage due to a decrease in adhesive strength or deterioration in sealing performance occurred. Furthermore, it was easy to peel off the lid and open the container, and no so-called "stiff mouth" due to residual adhesive layer on the lid was observed at the opening of the container.

Comparative Example 1 A lid material was produced in the same manner as in Example 1, except that no undercoat layer was formed, and a glass container was sealed. No water leakage occurred when the container was left upside down at room temperature for 3 months. However, when the lid material is removed and the package is opened, separation occurs between the aluminum foil and the EAA film, resulting in a "stiff mouth".
occurred.

Example 2 Thickness 50μ with printing layer and overcoat layer provided on one side
Apply ionomer emulsion 1-2Q/77J (as a solid content) as a primer to the other side of the aluminum foil (m), dry it at 180°C for 15 seconds, and then heat a 40 μm thick ionomer film on the surface. The lid material of the present invention was obtained by pressure bonding using a roll.

On the other hand, in order to simulate a glass container filled with powdered koshyo, heat sealing was performed under conditions of 230° C.Xlf/cdX for 2 seconds using the above-mentioned lid material.

The thus obtained sealed package was placed upside down at a temperature of 40°C.
Although it was left in an atmosphere with a humidity of 90% for 3 months, no abnormalities such as moisture absorption by the dust or peeling of the lid material were observed. Furthermore, it was easy to peel off the lid and open the container, and no "stiff mouth" was observed at the opening of the container.

Comparative Example 2 A lid material was produced in the same manner as in Example 2, except that no primer was used, and a glass container filled with Kosho was sealed. When left upside down in an atmosphere with a temperature of 40°C and a humidity of 90% for 3 months, no moisture absorption or peeling of the lid material was observed, but when the lid material was removed and the package was opened, the interface between the aluminum foil and the ionomer film was observed. The ionomer film peels off at the opening of the container, causing a “stiffness in the mouth”.
remained as.

Example 3 A modified polypropylene resin modified with maleic anhydride (acid value: 10j19-KOH/9) was dispersed in deodorized kerosene to prepare a 15% dispersion, and then an epoxy resin coating layer was provided on the - side. Coat it on the other side of aluminum foil with a thickness of 50 μm and bake it at 220°C for 30 seconds to form a layer with a thickness of 2 μm.
An undercoat layer was formed.

An unstretched polypropylene film having a thickness of 60 μm was thermocompression bonded at 200° C. on the undercoat layer to form an intermediate layer.

Modified polypropylene resin modified with maleic anhydride (1
A 15% dispersion was prepared by dispersing 11-valent: 3I1g KOH/g) in xylene, and γ-glycidoxypropyltrimethoxysilane was further added to obtain modified polypropylene/silane compound-10015 (solid content). (weight ratio) was obtained.

This bonding agent liquid was applied on the above intermediate layer, and
Dry for seconds to form a 4 μm thick topcoat bonding layer,
A lid material of the present invention was obtained.

The lid material obtained above was placed on the open end surface of a glass container filled with water, and heat-sealed at 230°C for 4 seconds/aJX for 2 seconds. The obtained sealed package was heated to 120°C
When subjected to retort sterilization for 30 minutes, no damage to the sealing part or water leakage occurred.

Further, when the sealed package obtained in the same manner as above was left in an inverted state at room temperature for 3 months, no water leakage due to a decrease in adhesive strength or deterioration in sealing performance occurred.

Comparative Example 3 A sealed package was obtained in the same manner as in Example 3, except that no silane coupling agent was used, and then retort sterilization was performed at 120°C for 30 minutes. As a result, the lid material was completely separated from the container. Oops.

Example 4 Modified polypropylene resin modified with maleic acid (M value:
After preparing a 15% dispersion by dispersing 3119-KOH/g') in a xylene/methyl isobutyl ketone mixture (1:1), a 90 μm thick aluminum foil with an epoxy resin coating layer on the - side was prepared. Apply it to the other side of the
Baking was performed at 20° C. for 30 seconds to form an undercoat layer with a thickness of 2 μm.

The undercoat layer is made of polypropylene with a thickness of 35 μm and a layer with a thickness of 5 μm.
m modified polypropylene (acid value: 3I1g・KOH/g
) The polypropylene side of the coextruded film was roll-pressed at 200°C to form an intermediate layer.

Modified polypropylene resin modified with maleic acid (IS!
Value: 10η KOH/9) 100 parts by weight and 50 parts by weight of epoxy resin were dispersed in an equal mixture of xylene/methyl isobutyl ketone/kerosene to make a 23% dispersion.
&, γ-7minopropyltrimethoxysilane was further added to obtain a binder liquid having a resin content/silane compound ratio of 100/10 (solid content weight ratio).

This bonding agent liquid was applied on the above intermediate layer, and
Dry for seconds to form a 5 μm thick topcoat bonding layer,
A lid material of the present invention was obtained.

The lid material obtained above was placed on the open end of the ceramic container filled with jelly, and heated at 230°C and 1.5 kg/dx.

Heat sealing was performed for 2 seconds.

The sealed package obtained in the same manner was heated at 80°C for 30 minutes.
When sterilized by boiling at 5° C. for 30 minutes and 95° C. for 30 minutes, no breakage or leakage of the sealed portion occurred.

Further, when the sealed package obtained in the same manner as above was left in an inverted state at room temperature for 3 months, no leakage due to a decrease in adhesive strength or deterioration of sealing performance occurred.

Further, it was easy to peel off the lid and open the container, and no stiffness was observed at the opening of the container due to residual adhesive layer on the lid.

Comparative Example 4 A lidding material was produced in the same manner as in Example 4 except that a urethane adhesive layer was formed in place of the undercoat layer, and then a ceramic container was sealed in the same manner as in Example 4. When the lid material was removed and the container was opened, a film consisting of an intermediate layer and a heat-sealing layer remained at the mouth of the container.

(that's all)

Claims (1)

[Scope of Claims] [1] (a) a base material, (b) an undercoat layer with a thickness of 1 to 10 μm mainly made of a modified polyolefin resin provided on one side of the base material, and (c) on the undercoat layer. The undercoat layer is made of a modified polyolefin resin with excellent adhesion and has a thickness of 10 to 10 mm.
A lid material for a sealed package characterized by having a bonding layer of 0 μm. [2] (a) Base material, (b) An undercoat layer with a thickness of 1 to 10 μm mainly made of a modified polyolefin resin provided on one side of the base material, (c) The undercoat layer provided on the undercoat layer. (d) 100 parts by weight of a modified polyolefin resin and a silane coupling agent provided on the intermediate layer, and (d) 100 parts by weight of a modified polyolefin resin and a silane coupling agent provided on the intermediate layer. A lid material for a sealed package, comprising a topcoat bonding layer of 1 to 20 μm thick and comprising 0.1 to 20 parts by weight. [3] (a) Base material, (b) An undercoat layer with a thickness of 1 to 10 μm mainly made of a modified polyolefin resin provided on one side of the base material, (c) The undercoat layer provided on the undercoat layer. and (d) an intermediate layer with a thickness of 10 to 100 μm made of a polyolefin resin and/or a modified polyolefin resin with excellent adhesive properties, and (d) 100 parts by weight of a modified polyolefin resin and 10 to 10 parts by weight of an epoxy resin provided on the intermediate layer. 100 parts by weight of a mixed resin consisting of 100 parts by weight and 0.0 parts by weight of a silane coupling agent.
1. A lid material for a sealed package, comprising a topcoat bonding layer having a thickness of 1 to 20 μm and containing 1 to 20 parts by weight.