JP2020104869A - Manufacturing method of resin container - Google Patents

Abstract

To provide a manufacturing method of a resin container which has a favorable shape retention property and which can exhibit high adhesion prevention effect even when a highly viscous content is always in contact with it.SOLUTION: In a method of manufacturing a container from a resin sheet 10: (1) the resin sheet is a laminate containing a) resin base material film 1, b) a ground layer 2 formed at least on one surface of the resin base material film, c) and a functional layer 3 formed on the ground layer; and (2) a process is included of manufacturing a container by molding the sheet by thermoforming the resin sheet for molding.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method of manufacturing a container from a resin sheet.

In various products such as foods, beverages, pharmaceuticals, and cosmetics, various contents such as yogurt, jelly, pudding, liquid detergent, toothpaste, retort food, syrup, dressing, face cream are packed in a package. ing. For these packages, a packaging material having a function according to each content is used. Among these packaging materials, a resin container obtained by molding a resin sheet or the like is also widely used as one form of packaging material.

Taking a resin container for containing food as an example, for example, packed lunches sold in convenience stores, supermarkets, side dishes, confectioneries such as Western confectionery and Japanese confectionery, ice cream, packaging of processed foods such as pet food. For this, various resin containers are used. Among them, foods with high water content and highly viscous foods exposed on the surface, such as honey from mitarashi dumplings and sweet bean paste, are used as packaging materials when taking them out. Since it adheres and becomes difficult to take out, it is filled in the packaging material (bag) in a state of being placed on a resin-made container that is molded in a tray shape or the like in advance.

In recent years, as such a resin container, one having anti-adhesion properties has been studied, and for example, a resin container provided with a water repellent layer made of an olefin-based copolymer resin containing hydrophobic oxide fine particles has been proposed. (Patent Document 1).

Further, a technique is known in which a laminate having hydrophobic oxide fine particles having an average primary particle diameter of 3 to 100 nm attached to at least a part of the surface of a layer containing a thermoplastic resin is used as a packaging material (Patent Document). 2).

International publication WO2014/87695 JP, 2011-93315, A

However, in the resin container disclosed in Patent Document 1, since the water-repellent layer contains a relatively large amount of the resin component, contact between the content and the resin component increases, resulting in, for example, a large amount of water and high viscosity. A sufficient anti-adhesion effect cannot be obtained for food materials. For this reason, it becomes difficult to take out the contents from the resin container, and even if it is taken out, a part of the surface of the contents adheres to the resin container and is detached, which deteriorates the appearance of the contents (food etc.). There is a problem. In addition, the resin container also has a drawback that the content is stuck to the container when the content is taken out and is greatly deformed, and the resin container cannot be used as a dish during eating. Further, it is necessary to irradiate with an electron beam for the crosslinking treatment of the uneven layer on the surface of the container, which is disadvantageous in terms of manufacturing process or cost.

When the packaging material described in Patent Document 2 is molded into a container having a shape-retaining property and is housed in the container while being in constant contact with a highly viscous food, such highly viscous food (foodstuff) ) Tends to adhere to the container side and part of it tends to remain on the container side, so there is room for further improvement.

Therefore, a main object of the present invention is to provide a method for producing a resin container which has a good shape-retaining property and can exhibit a high anti-adhesion effect even when a highly viscous content is always in contact therewith.

The present inventor has conducted intensive studies in view of the problems of the prior art, and as a result, found that the above object can be achieved by a method of thermoforming a packaging material having a specific constitution, and completed the present invention.

That is, the present invention relates to the following resin container manufacturing method.
1. A method of manufacturing a container from a resin-based sheet,
(1) A resin-based sheet is a laminate including a) a resin-based substrate film, b) a base layer formed on at least one surface of the resin-based substrate film, and c) a functional layer formed on the base layer. The body,
a) The resin-based substrate film has a thickness of 100 μm or more,
b) the underlayer contains b1) an adhesive resin component and filler particles having an average particle size D50 of 6 to 50 μm, and b2) has a dry weight of 1.0 to 10.0 g/m ² .
c) the functional layer contains c1) at least one kind of hydrophobic fine particles and oleophobic fine particles, and c2) has a dry weight of 0.3 to 10 g/m ² .
(2) A method of manufacturing a resin container, comprising a step of manufacturing the container by thermoforming the resin sheet.
2. The container includes 1) a bottom portion, 2) a sidewall portion rising from the outer circumference of the bottom portion, 3) an opening portion formed from an upper end portion of the sidewall portion, and 4) a flange portion extending from the opening portion in a container outer peripheral direction, Item 2. The manufacturing method according to Item 1.
3. Item 2. The production method according to Item 1, wherein the resin-based substrate film is at least one of polyethylene terephthalate-based resin, polyolefin-based resin, and polystyrene-based resin.
4. Item 2. The production method according to Item 1, wherein the filled particles are resin beads having a melting point of 90 to 350°C.
5. Item 5. The method according to Item 4, wherein the resin beads have a specific gravity of 0.93 to 1.30.

According to the present invention, it is possible to provide a method for producing a resin-made container capable of exhibiting a good shape-retaining property and a high anti-adhesion effect even when a highly viscous content is always in contact therewith. In particular, in the manufacturing method of the present invention, since the container is prepared by thermoforming a sheet including a specific underlayer and a functional layer in advance, the container is compared with a case where the functional layer or the like is formed in a later step. It is possible to provide a container having more uniform water repellency and/or oil repellency over the whole (in particular, corners, details, etc.).

Since the functional layer is formed on the inner surface of the container obtained by the production method of the present invention, it is possible to provide a resin container capable of exhibiting a high adhesion preventing effect even when a highly viscous content is always in contact therewith. .. As a result, it is possible to effectively suppress or prevent the adhesion of the food to the inner surface of the resin container even if the highly viscous food is stored in the container in such a state that it is always in contact with the food. That is, it is possible to effectively suppress the phenomenon that the food (foodstuff) is stuck to the container and a part of the food remains on the container side. Further, since the container produced by the production method of the present invention has excellent shape retention, the appearance of the contents can be effectively protected during storage, transportation and use of the product including the container.

Resin containers with such characteristics can be used, for example, not only for filling foods into bags but also for side dishes such as lunch boxes, Daifuku rice cakes for over-the-counter sales, Mitarashi dumplings, takoyaki, etc. The present invention can also be applied to applications where food is placed on a container and eaten as it is, and further, it can be applied as a container for accommodating pharmaceuticals, cosmetics, industrial products and the like other than food.

It is a figure which shows the specific example of the layer structure of the resin sheet of this invention. It is a cross-sectional schematic diagram of the container obtained by shape|molding the resin sheet of this invention.

The manufacturing method of the present invention is a method for manufacturing a container from a resin-based sheet,
(1) A resin-based sheet is a laminate including a) a resin-based substrate film, b) a base layer formed on at least one surface of the resin-based substrate film, and c) a functional layer formed on the base layer. The body,
a) The resin-based substrate film has a thickness of 100 μm or more,
b) the underlayer contains b1) an adhesive resin component and filler particles having an average particle size D50 of 6 to 50 μm, and b2) has a dry weight of 1.0 to 10.0 g/m ² .
c) the functional layer contains c1) at least one kind of hydrophobic fine particles and oleophobic fine particles, and c2) has a dry weight of 0.3 to 10 g/m ² .
(2) The method is characterized by including a step (molding step) of producing a container by thermoforming the resin sheet.

1. Molding Resin-Based Sheet In the present invention, a resin-based sheet containing each of the layers a), b) and c) is used as a molding sheet. A specific example of the layer structure of the resin sheet is shown in FIG. The resin-based sheet 10 is composed of a laminate including a resin-based substrate film 1, a base layer 2 laminated on the surface of the resin-based substrate film, and a functional layer 3 laminated on the surface of the base layer. .. In particular, the functional layer 3 functions as an adhesion preventing layer. The functional layer 3 is preferably a porous layer in which a plurality of hydrophobic particles and/or oleophobic particles are fixed to each other to form a three-dimensional network structure.

It is preferable that the respective layers constituting the resin-based sheet are laminated so as to be in direct contact with each other, but other layers may be included within a range not impairing the effects of the present invention. Moreover, each layer may be a layer in which two or more layers are laminated. Hereinafter, each layer constituting the resin sheet will be described.

(1) Resin-based substrate film The material of the resin-based substrate film is not particularly limited, and a resin material used in known containers can be used. Therefore, for example, at least one kind of synthetic resin film can be mentioned.

Examples of the synthetic resin include polyethylene terephthalate-based, polybutylene terephthalate-based polyester-based, polystyrene-based, polyethylene-based, polyolefin-based such as polypropylene-based, polyvinylidene chloride-based, and nylon. In the present invention, it is preferable that at least one of polyethylene terephthalate type, polyolefin type and polystyrene type is contained. Any of these may be publicly known or commercially available.

As the above polyolefin-based film such as polystyrene-based, polyethylene-based, polypropylene-based, etc., a copolymer composed of a copolymer of olefin monomers can be preferably used, but within the range not hindering the effect of the present invention. You may include the copolymer with the monomer of.

Further, the resin-based substrate film may be a film containing the above resin component as a main component (particularly usually 50% by weight or more, preferably 80% by weight or more, more preferably 95% by weight or more), Other components (filler, colorant, antistatic agent, ultraviolet absorber, oxygen absorber, etc.) may be contained within a range that does not impair the effects of the present invention. Further, for example, a polymer alloy film or the like may be used in addition to the mixed resin film in which other resin components are mixed.

Further, the resin-based substrate film may be unstretched or stretched. In the case of foods, food applications, etc. where strength and heat resistance are particularly important, a stretched film (particularly a biaxially stretched film) is preferable. From the viewpoint of moldability, it is preferable to use an unstretched film. Therefore, for example, in the present invention, a non-stretched polyethylene terephthalate film can be preferably used.

The resin-based substrate film may be a single layer type or a multilayer type in which a plurality of layers are laminated. In the case of the multi-layer type, by bonding a plurality of films (functional films), for example, antibacterial properties, gas barrier properties, oxygen/water absorption properties, etc. can be imparted, resulting in higher added value. ..

As the multilayer type film, for example, a laminate in which one layer or two or more layers of other layers are formed on at least one surface of a polyethylene terephthalate film or a polyolefin film can be used as a resin substrate film. Examples of other layers include a printing layer, an overcoat layer, an adhesive layer, a primer coat layer, an anchor coat layer, an anti-slip agent layer, a lubricant layer, an antifogging agent layer, a gas barrier layer, and the like. Therefore, for example, a printing layer, an overcoat layer, or the like is provided on the surface opposite to the surface on which the resin-based substrate film comes into contact with the contents (that is, the surface exposed on the outside when molded into a container shape). It can be laminated, or various films can be appropriately laminated. In the case of a multi-layer type, a printing layer may be provided as the outermost surface or the intermediate layer of the resin-based substrate film.

In particular, in the present invention, when a non-stretched polyethylene terephthalate-based film or a biaxially stretched polystyrene-based film is used as the resin-based substrate film, either a single layer type or a multilayer type can be used. In particular, as a multilayer type film, for example, a laminate including an unstretched polyethylene terephthalate film or a polystyrene film and a heat seal layer formed on at least one surface thereof is preferably used as a resin base film. it can. For example, when an unstretched polyethylene terephthalate-based film is used as a substrate, a laminate including a printing layer, an adhesive layer and an unstretched polyethylene terephthalate-based film in that order can be preferably used as the resin-based substrate film.

When the adhesive layer is formed, the adhesive that can be used is not particularly limited as long as it can be used for food applications, and for example, a laminating adhesive or the like can be preferably used. Examples of components of the laminating adhesive include polyester adhesives, polyether adhesives, polyurethane adhesives and the like. Further, the property is not limited, and any of solvent type, solventless type, aqueous type and the like can be used. For example, in the present invention, a laminate formed by laminating two or more polyethylene terephthalate films via a polyurethane laminate adhesive layer can be preferably used as the resin base film. In addition, the film may be formed by applying a coating solution containing hydrophobic particles and/or oleophobic particles as necessary and drying, and then laminating the surface opposite to that surface with another substrate.

The thickness of the resin-based substrate film is usually 100 μm or more, but is preferably 100 to 2000 μm, and more preferably 150 to 800 μm. When the thickness of the resin-based substrate film is less than 100 μm, it may be difficult to maintain the shape of the molded container and the placed contents cannot be retained. When the thickness is more than 2000 μm, the coil winding length for practical use is shortened, and it takes a long time for molding, which may significantly reduce productivity and yield. In addition, the said thickness says the total thickness, when a resin type base material film is a multilayer type.

In addition, in the present invention, the film is not limited to a film having a thickness of less than 250 μm as defined by the definition of JIS film, and a sheet having a thickness of 250 μm or more is also included.

(2) Underlayer In the present invention, by interposing an underlayer between the resin-based substrate film and the functional layer, fine irregularities can be provided on a relatively smooth substrate film, resulting in the contents and the container. Since the contact area with the inner surface can be reduced, higher anti-adhesion can be obtained.

The underlayer is formed of a composition containing an adhesive resin component and filler particles having an average particle diameter D50 of 6 to 50 μm.

As the adhesive resin component, a known adhesive containing an adhesive resin component can be used. For example, components used in adhesives such as lacquer type adhesives, easy peel adhesives and hot melt adhesives can be adopted in addition to the constituent components of known or commercially available sealant films.

The adhesive resin component is not limited, and examples thereof include adhesives such as polyolefin resin, polyester resin, polyurethane resin, epoxy resin, acrylic resin, vinyl resin and the like. More specifically, low density polyethylene, medium density polyethylene, high density polyethylene, linear (linear) low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid copolymer. , Acryl-vinyl chloride copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, methylpentene polymer, polybutene polymer -, an acid-modified polyolefin resin obtained by modifying a polyolefin resin such as polyethylene or polypropylene with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid or itaconic acid, or a polyvinyl acetate resin In addition to poly(meth)acrylic resins, polyacrylonitrile resins, polyvinyl chloride resins, and other thermoplastic resins, blended resins of these, copolymers containing a combination of monomers constituting them, modified resins, etc. can do. Therefore, for example, a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer and the like can also be suitably used.

The content of the adhesive resin component in the underlayer may be appropriately set according to the type of the adhesive resin component used, etc., and is usually about 50 to 97% by weight, and further 60 to 95% by weight. However, the present invention is not limited to this. Therefore, for example, it can be set to about 70 to 90% by weight.

As the filling particles, filling particles containing at least one of an organic component and an inorganic component can be adopted.

Examples of the inorganic component include 1) metals such as aluminum, copper, iron, titanium, silver and calcium, or alloys or intermetallic compounds containing these, 2) silicon oxide, aluminum oxide, zirconium oxide, titanium oxide, iron oxide and the like. Oxides, 3) inorganic or organic acid salts such as calcium phosphate and calcium stearate, 4) glass, 5) ceramics such as aluminum nitride, boron nitride, silicon carbide and silicon nitride can be preferably used.

Examples of the organic component include acrylic resin, urethane resin, melamine resin, amino resin, epoxy resin, polyethylene resin, polystyrene resin, polypropylene resin, polyester resin, cellulose resin, vinyl chloride resin. It is preferable to suitably use an organic polymer component (or resin component) such as polyvinyl alcohol, polyvinyl alcohol, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-ethyl acrylate copolymer, polyacrylonitrile, and polyamide. it can.

As the filling particles, in addition to particles made of an inorganic component or particles made of an organic component (powder), particles made of both an inorganic component and an organic component (powder) can be used. Among these, it is more preferable to use at least one kind of acrylic resin particles, hydrophilic silica particles, calcium phosphate particles, carbon powder, calcined calcium particles, uncalcined calcium particles, and calcium stearate particles.

Of these filling particles, filling particles made of an organic component are preferable, and resin beads are particularly preferable. In particular, it is preferable that at least one kind of polyethylene resin beads, polypropylene resin beads, and acrylic resin beads is contained, and the specific gravity of the resin beads is 0.93 to 1.30. Furthermore, acrylic resin beads are more preferable in that they are less likely to be deformed by heat and pressure during molding. In the case of resin beads, the melting point of the resin is usually preferably 90 to 350°C, and more preferably 150 to 300°C. If the melting point is less than 90° C., it may be melted by the heat during molding, and the desired effect of the uneven shape may not be obtained. Further, if the melting point exceeds 350° C., it may be a factor that hinders moldability.

In addition, the average particle size of the filled particles (average particle size at 50% accumulation calculated based on the volume average particle size distribution measured by a laser diffraction particle size distribution meter, D50) is 6 μm or more and 50 μm or less, and 15 μm or more. More preferably, it is 30 μm or less. If it is less than 6 μm, sufficient performance cannot be exhibited in terms of forming a gap. On the other hand, when it exceeds 50 μm, it is not suitable in terms of falling of the filling particles, dispersibility, deterioration of moldability, occurrence of film cracks and the like. Also from the viewpoint of processing, for example, coating unevenness is likely to occur, which may affect the appearance or performance. The shape of the filled particles is not limited, and may be, for example, spherical, spheroidal, irregular, teardrop-shaped, flat, hollow, or porous.

The content of the filler particles in the underlayer may be appropriately set according to the type and size of the filler particles to be used, and usually the solid content is preferably about 10 to 50% by weight. Not limited to.

The formation amount of the underlayer depends on the kind of the filling particles used and the like, but normally, it may be about 1.0 to 10.0 g/m ² as a dry weight, and particularly 2.0 to 8.0 g/m. It is preferably ² . If the amount formed is less than 1.0 g/m ² , the effect of maintaining water repellency may be reduced or the shape retention of the content may be reduced. Further, even if the formed amount exceeds 10.0 g/m ² , the effect of unevenness is reduced, and the contents may adhere to the inner surface of the package. The formation amount of the underlayer is the weight (weight per unit area) obtained by subtracting the weight of the resin-based substrate film from the weight of the laminate after drying after the coating operation.

(Method of forming underlayer)
The method for forming the underlayer is not particularly limited, but a step of applying a coating liquid (coating liquid A) containing an adhesive resin component and filler particles to at least one surface of the resin-based substrate film and drying the coating liquid. Can be suitably implemented by a method including.

The coating liquid A is not particularly limited, but for example, a solution obtained by dissolving or dispersing an adhesive resin component in an organic solvent or a mixed liquid in which filler particles are dispersed in a dispersion liquid can be preferably used.

The organic solvent can be appropriately selected depending on the type of thermoplastic resin used. For example, alcohol (methanol, ethanol), cyclohexane, toluene, ethyl acetate, methyl ethyl ketone (MEK), methyl cyclohexane (MCH), acetone, isopropyl alcohol (IPA), propylene glycol, hexylene glycol, butyl diglycol, pentamethylene glycol, It can be appropriately selected from organic solvents such as normal pentane, normal hexane, and hexyl alcohol.

The content of the thermoplastic resin in the coating liquid A is not limited, but is usually about 5 to 40% by weight, preferably 10 to 30% by weight.

Further, the content of the filling particles in the coating liquid A may be set such that the content after coating and drying is within the range shown above. Therefore, for example, it can be set to 3 to 30% by weight in the coating liquid.

In addition, other additives can be appropriately added to the coating liquid A, if necessary, within a range that does not impair the effects of the present invention. For example, a dispersant, a colorant, an anti-settling agent, a viscosity modifier, a defoaming agent and the like can be added.

The method of applying the coating liquid A is not particularly limited, and any known method such as roll coating, various gravure coating, bar coating, doctor blade coating, comma coater, and brush coating can be adopted. For example, when roll coating or the like is adopted, the anti-adhesion layer forming step is performed by forming a coating film on the underlayer using a dispersion liquid in which hydrophobic fine particles and/or oleophobic fine particles are dispersed in a solvent. can do.

The area to be coated with the coating liquid A may be set so as to include at least the surface on which the functional layer is formed, and it is particularly preferable to coat the entire surface on which the functional layer is formed. In this case, it may be applied to a region where the functional layer is not formed.

After coating, the coated surface is dried to obtain a film in which a base layer is formed on the resin-based substrate film.

The drying method is not particularly limited and may be natural drying or heat drying. When heating and drying, the temperature is usually 80 to 200° C., and particularly 100 to 160° C. The heating time may be appropriately set according to the heating temperature and the like, but is usually about 3 to 30 seconds. The obtained film may be processed (cut, etc.) into a specific shape in advance before or after forming the coating film, if necessary, to facilitate thermoforming.

(3) Functional layer The functional layer functions as an adhesion preventing layer by exhibiting water repellency and/or oil repellency. Therefore, at least one kind of hydrophobic fine particles and oleophobic fine particles is included (hereinafter, these are also referred to as “anti-adhesive particles”). As a result, the resin molded container is provided with water repellency and/or oil repellency, and even if the content is highly viscous and highly viscous, adhesion and the like can be more effectively suppressed or prevented. Specifically, when the contents to be placed in the container are foods with a low fat content and a high water content, hydrophobic fine particles may be applied to the surface of the resin-based substrate film. On the other hand, when the content placed in the container is a food having a large amount of fat, it is preferable to impart fine particles having a coating layer of a polyfluoroalkylmethacrylate resin to the resin-based substrate film as oleophobic particles.

The hydrophobic particles are not particularly limited, but when a resin container is used as a food container, hydrophobic oxide fine particles can be preferably used because it is suitable for food. The hydrophobic oxide fine particles are not particularly limited, but for example, at least one kind of particles (powder) of silicon oxide, titanium oxide, aluminum oxide, zinc oxide or the like can be preferably used. Among them, silicon oxide particles are more preferable.

The average primary particle diameter of these particles is preferably 5 to 50 nm, and more preferably 7 to 30 nm. The average primary particle diameter of the particles can be measured using a transmission electron microscope or a scanning electron microscope. More specifically, the average primary particle diameter is obtained by photographing with a transmission electron microscope or a scanning electron microscope, measuring the diameters of 200 or more particles on the photograph, and calculating the arithmetic mean value thereof. be able to.

The hydrophobic oxide fine particles preferably form a porous layer having a three-dimensional network structure, and the thickness thereof is preferably about 0.1 to 5 μm, more preferably about 0.2 to 2.5 μm. By adhering in such a porous layer state, a large amount of air can be contained in the layer, and more excellent non-adhesiveness can be exhibited.

As the above hydrophobic oxide fine particles, known or commercially available ones can be used. For example, as silica, product names "AEROSIL R972", "AEROSIL R972V", "AEROSIL R972CF", "AEROSIL R974", "AEROSIL RX200", "AEROSIL RY50", "AEROSIL NY50", "AEROSIL RY200S", AEROSIL R "AEROSIL RY200" (above, manufactured by Nippon Aerosil Co., Ltd.), "AEROSIL R202", "AEROSIL R805", "AEROSIL R711", "AEROSIL R7200", "AEROSIL R812", "AEROSIL R812S", (above, Evonik Degussa Manufactured by Fuji Silysia Chemical Co., Ltd.), “Silohobic 100”, “Silohobic 200”, “Silohobic 603” (above, manufactured by Fuji Silysia Chemical Ltd.) and the like. Examples of titania include the product name “AEROXIDE TiO ₂ T805” (manufactured by Evonik Degussa). Examples of the alumina include fine particles whose surface is made hydrophobic by treating a product name “AEROXIDE Alu C” (manufactured by Evonik Degussa) with a silane coupling agent.

Among these, hydrophobic silica fine particles can be preferably used. In particular, hydrophobic silica fine particles having a trimethylsilyl group on the surface are preferable in that a more excellent anti-adhesion effect can be obtained. Examples of commercially available products corresponding to this include “AEROSIL R972”, “AEROSIL R812”, and “AEROSIL R812S” (all manufactured by Evonik Degussa).

The oleophobic particles are not limited, but for example, composite particles having a coating layer containing a polyfluoroalkylmethacrylate resin on the surface of oxide fine particles (hydrophilic oxide fine particles and the like) can be used. By using such composite particles, for example, even in the case of a content having a large amount of fat, the adhesion can be effectively reduced.

The particle size of the composite particles can be suitably used within the range of about the same as the above-mentioned hydrophobic oxide fine particles. That is, the average primary particle diameter is preferably 5 to 50 nm, and more preferably 7 to 30 nm.

As described above, as the composite particles, it is possible to preferably use the composite particles in which the oxide fine particles are used as the core particles and the coating layer of the polyfluoroalkyl methacrylate resin or the like is formed on the surface thereof.

As the above oxide fine particles, for example, as silicon oxide, product name "AEROSIL 200"("AEROSIL" is a registered trademark; the same applies hereinafter), "AEROSIL 130", "AEROSIL 300", "AEROSIL 50", "AEROSIL 200FAD" , "AEROSIL 380" (above, manufactured by Nippon Aerosil Co., Ltd.) and the like. Examples of titanium oxide include a product name “AEROXIDE TiO ₂ T805” (manufactured by Evonik Degussa). Examples of aluminum oxide include the product name “AEROXIDE Alu C 805” (manufactured by Evonik Degussa). By using particles having such a coating layer, it is possible to form a strong coating layer having relatively high adhesiveness on the surface of the particles because it has excellent affinity with the oxide fine particles, and it is possible to obtain a high non-content property. Adhesiveness can be expressed.

The polyfluoroalkylmethacrylate resin that constitutes the coating layer is not particularly limited, and known or commercially available products can be used. Examples of commercially available products include product name "CHEMINOX FAMAC-6" (manufactured by Unimatec (Japan)), product name "Zonyl TH Fluoromonomer Code 421480" (manufactured by SIGMA-ALDRICH (USA)), product name "SCFC-65530-". 66-7" (manufactured by Maya High Purity Chem (CHINA)), product name "FC07-04 to 10" (Fluory, Inc (USA)), product name "CBINDEX:58" (Wilshire Chemical Co., Inc (USA). ) Company name, product name "Asahi Guard AG-E530", "Asahi Guard AG-E060" (all manufactured by Asahi Glass Co., Ltd.), product name "TEMAc-N" (Top Fluorochem Co., LTD (CHINA) company. ), product name “Zonyl 7950” (manufactured by SIGMA-RBI (SWITZ)), product name “6100840 to 6100842” (manufactured by Weibo Chemical Co., Ltd., Ltd.), product name “CB INDEX:75” (ABCR). GmbH & CO.KG (manufactured by GERMANY)) and the like.

Among these, for example, a) polyfluorooctylmethacrylate, b) 2-N,N-diethylaminoethylmethacrylate, c) 2-hydroxyethylmethacrylate and d)2 from the viewpoint that more excellent water repellency and oil repellency can be achieved. A copolymer obtained by copolymerizing 2,2'-ethylenedioxydiethyldimethacrylate can be preferably used as the resin. These may be commercially available products as described above.

Since these oleophobic particles are provided with a polyfluoroalkylmethacrylate resin on the surface thereof, a strong coating layer having relatively high adhesion is formed on the surface of the particles because of having excellent affinity with oxide fine particles. In addition, it is possible to develop high non-adhesiveness to the contents.

The method for preparing the composite particles is not particularly limited, and a coating layer is formed on the above oxide fine particles (powder) using a polyfluoroalkylmethacrylate resin as a coating material according to a known coating method, granulation method, or the like. Just do it. For example, it can be suitably prepared by a production method including a step (coating step) of coating a coating solution in which a liquid polyfluoroalkylmethacrylate resin is dissolved or dispersed in a solvent on oxide fine particles.

In the above manufacturing method, a polyfluoroalkyl methacrylate resin that is in a liquid state at room temperature (25° C.) and normal pressure can be preferably used. As such a polyfluoroalkylmethacrylate resin, the commercially available products exemplified above can also be used.

The solvent used in the coating liquid is not particularly limited, and in addition to water, organic solvents such as alcohol and toluene can be used, but water is preferably used in the present invention. That is, it is preferable to use a coating liquid in which a polyfluoroalkyl methacrylate resin is dissolved and/or dispersed in water as the coating liquid.

The content of the polyfluoroalkylmethacrylate resin in the coating liquid is not particularly limited, but is generally 10 to 80% by weight, particularly 15 to 70% by weight, and further 20 to 60% by weight. It is preferable to set.

The method for coating the coating liquid on the surface of the oxide fine particles may be a known method, and for example, any of a spray method, a dipping method, a stirring granulation method and the like can be applied. Particularly, in the present invention, the coating by the spray method is particularly preferable in terms of excellent uniformity and the like.

After coating the coating liquid, the solvent is removed by heat treatment to obtain composite particles. The heat treatment temperature is usually about 150 to 250°C, and particularly preferably 180 to 200°C. The heat treatment atmosphere is not limited, but an inert gas (non-oxidizing) atmosphere such as nitrogen gas or argon gas is desirable. Further, for example, if necessary, a series of steps including a coating step and a heat treatment step can be performed once or more. This makes it possible to suitably control the amount of coating.

The content of at least one kind of hydrophobic particles and oleophobic particles in the functional layer is preferably 10 to 100% by weight. When the content of these particles approaches 100% by weight, higher water repellency and/or oil repellency can be obtained.

(Method of forming functional layer)
The method for forming the functional layer is not particularly limited, but in particular, a dispersion liquid (coating liquid B) in which at least one kind of hydrophobic fine particles and oleophobic fine particles is dispersed in a solvent is applied to part or all of the surface of the underlayer. It can be suitably carried out by a method including a step of drying and drying.

The solvent used for the coating liquid B is not particularly limited, and one kind or two or more kinds of solvents used in food production such as water and ethanol can be used.

The content of the hydrophobic fine particles and/or the oleophobic fine particles in the coating liquid B is not particularly limited, but generally it is preferably set appropriately within the range of about 5 to 200 g/L (liter).

In addition, the coating liquid B contains a dispersant, a colorant, an anti-settling agent, a viscosity modifier, a binder agent, a defoaming agent and the like, if necessary, within a range that does not impair the effects of the present invention. May be.

The method for applying the coating liquid B onto the underlayer is not particularly limited, and known methods such as roll coating, various gravure coatings, bar coating, doctor blade coating, comma coater and brush coating may be appropriately adopted. it can. By mixing the hydrophobic fine particles and/or the oleophobic fine particles in the dispersion medium, more uniform coating can be achieved.

The coating amount (after drying weight), but it can be appropriately set according to the desired water repellency or oil repellency, usually a 0.3 to 10 / ^{m 2} or so, be particularly 0.4~1g / ^{m 2} preferable. By setting the amount within the above range, a porous layer composed of the anti-adhesive particles can be formed more reliably, and as a result, superior non-adhesiveness (anti-adhesive effect) can be obtained for a long period of time, and fine particles can be obtained. It is even more advantageous in terms of prevention of dropouts and cost.

After coating, the coated surface is dried to obtain a film in which anti-adhesion particles are attached to the resin-based substrate film. The drying method is not particularly limited and may be natural drying or heat drying. When drying by heating, the temperature is usually about 60 to 190°C, and particularly preferably 80 to 150°C. The heating time may be appropriately set according to the heating temperature and the like, but is usually about 3 to 30 seconds.

Regarding the water repellency of the coated surface, the contact angle of pure water (25° C.) is usually 140 degrees or more, and particularly preferably 150 degrees or more. Regarding oil repellency, the contact angle of edible oil: olive oil (25° C.) is 130 degrees or more, and particularly preferably 140 degrees or more. Furthermore, the falling angle (olive oil) of the coating film is not limited, but it is usually preferably 3 to 20 degrees.

2. Molding Step In the present invention, thermoforming is performed using the resin sheet described in “1. Resin sheet for molding” above as a molding sheet (starting material).

A known method can be adopted as the thermoforming method itself. It can also be carried out using a known or commercially available molding machine. For example, any of pressure air molding (pressurized air only), vacuum molding (vacuum drawing only), vacuum pressure air molding (pressurized air+vacuum drawing), press molding and the like can be adopted. The heating method is not limited, and for example, a) radiant heating with infrared rays, b) direct heating by contact with a hot plate, or the like can be used. Among them, in the present invention, in particular, the resin-based sheet as the base material has less uneven thickness, and the shape of the molding die can be transferred to the corners of the container. Molding method) can be preferably adopted.

The conditions for thermoforming are not limited, but, for example, in the case of hot plate vacuum pressure molding, air pressure (compressed air and vacuum): 0.5 to 6 kgf/cm ^{2 is} applied to a hot plate previously heated to 100 to 230°C. (E.g. 1 to 5 kgf/cm< ² >) and time: pressing for more than 1 second and less than 40 seconds (e.g. 2-35 seconds), and then air pressure (pneumatic and vacuum) 0.5 to 11 kgf/cm< ² > (e.g. 1 to 8 kgf/). cm ² ) and the time is more than 1 second and less than 10 seconds (for example, 2 to 9 seconds), the resin sheet is pressed against a molding die to be molded into an arbitrary shape, thereby obtaining a molded body. In this way, it is possible to obtain a molded body which is a tray-shaped container having a bottom surface and side surfaces. The resin sheet may be formed by contacting either side with the hot plate, the functional layer may come into direct contact with the hot plate, or the hot plate may be directly attached to the surface opposite to the functional layer. You may contact. The obtained molding container is generally provided with an anti-adhesion property on the inside of the concave shape, but it can also be used by imparting an anti-adhesion property on the outside of the concave shape.

Further, in the present invention, in the container mold design, the container is prevented from cracking at the edge portion (the most extended part of the bottom corner consisting of the bottom wall and the side wall), the releasability from the mold is improved, and the injury of the user is prevented. It can also be rounded for purposes such as. In this case, the radius of the roundness can be changed depending on the size of the container, the thickness of the resin-based sheet, and the like, and is not limited, but from the viewpoint of maintaining the adhesion prevention property, it is preferably about 1 to 30 mm, for example. If it is less than 1 mm, the effect of maintaining anti-adhesion properties may be reduced. When it exceeds 30 mm, the strength of the container is insufficient, and the container is likely to be deformed or cracked when being square-struck, and as a result, the adhesion prevention property may be deteriorated.

3. Container for food The container (the container of the present invention) obtained by the production method of the present invention can be suitably used particularly as a resin container for food. That is, it is possible to provide a container which is used for containing food and to which the food does not easily adhere. The container of the present invention includes, for example, what is called a tray, a case, a cup or the like.

Examples of the container of the present invention include a container having a bottom surface and a side surface. The basic structure of this container is shown in FIG. As shown in FIG. 2, the food container 20 has a bottom portion 22 and a side wall portion 23 rising from the outer periphery thereof, and includes an upper opening portion 24 of the side wall portion and a flange portion 25 extending from the upper opening portion 24 in the outer peripheral direction of the container. Further, ribs may be provided on the side wall portion 23 or the like in order to prevent rotation of the container stack or deterioration of the adhesion preventing function.

The planar shape of the container may be, for example, a circle, an oval, an ellipse, a polygon, or the like. Therefore, for example, a cup-shaped container having a bottom surface and side surfaces can be exemplified. Such containers are cheap and easy to use as containers for confectioneries such as Western confectionery and Japanese confectionery, as well as for guest bread such as confectionary bread and prepared bread, and processed foods such as ice cream and pet food. You can

In the container of the present invention, a functional layer having anti-adhesion property is formed on at least the surface that comes into contact with food. In the container shown in FIG. 2, the resin-based sheet 10 is produced by thermoforming, and the functional layer 3 is arranged as the outermost surface layer of the inner surface of the container (the notation of the resin-based substrate film and the base layer). Is omitted.).

When food is stored as the contents in such a container of the present invention, even if the food comes into contact with the inner surface of the container, the functional layer 3 prevents the food from adhering to the inner surface of the container. As a result, the food can be eaten without waste without being left on the container side, and cleaning of the container can be omitted.

The container of the present invention, as long as it is used for food, the type of food is not limited, in addition to fresh food, pre-cooked food (for example, Western confectionery, Western half-baked confectionery, Japanese confectionery, Japanese half-baked confectionery, sweet bread, side dish, It can also be suitably used as a side dish for lunch etc.).

The property of the food is not limited, and it can be applied to, for example, a solid material and a fluid material. Further, the content may be a gel-like material or a non-gel-like material. Further, the content may be a material containing at least one of water and oil (oils and fats), and in particular, the package of the present invention can be applied to a material containing both water and oil.

In particular, the container body of the present invention can be suitably used for contents containing a material that easily sticks to the inner surface of the container. As a typical example of such a material, a liquid material (including a semi-solid material, a gel-like substance, and the like) can be given. Among them, a liquid material having a relatively high viscosity at room temperature (for example, a viscosity of about 1×10 ³ to 1×10 ⁵ mPa·s at 25° C.) is generally easily attached to the inner surface of the container. The container of the present invention is also advantageous for packaging contents whose contents are exposed to the outside. Specific examples of such a liquid material include, for example, fresh cream, custard cream, whipped cream, bean paste, syrup, honey, confectionery bread in which jam and the like are exposed to the outside, Western confectionery, Japanese confectionery, etc., for example, sauce, tomato ketchup. , Side dishes such as mayonnaise whose seasoning is exposed to the outside (including side dish bread, bento, etc.) and the like.

The food container mainly means a container on which food is placed, and can be suitably used, for example, as a tray-shaped (including cup-shaped) container. The food to be placed is not limited, but it can be suitably used for foods having high water content and high viscosity such as mitarashi dumplings and ohagi as described above. It is assumed that such a container will be used by being laid under the food, and the upper part of the food will be exposed. It can also be used favorably for those packed in a bag. Further, it can be suitably used as a side dish for side dishes such as lunch boxes. In particular, since such a container has a shape-retaining property, it is possible to prevent the food or a part thereof from falling or leaking out from the container.

The shape as a tray-shaped molded container is not particularly limited, but a container molded into a shape having a bottom portion and a side wall portion rising from the outer periphery thereof, and a flange portion extending from the upper portion of the side wall in the outer peripheral direction of the container is a edible food. It is preferably used as a container.

The features of the present invention will be described more specifically below with reference to Examples and Comparative Examples. However, the scope of the present invention is not limited to the examples.

Example 1
(1) Preparation and coating of undercoating agent Polymethyl methacrylate beads (product name "MBX-") as filling particles with respect to 100 parts by weight of a solution of a thermoplastic polyester resin (solvent: toluene, solid content: 20% by weight) 20" by Sekisui Plastics Co., Ltd., average particle size: 20 μm, melting point: 250-270° C.) 10 parts by weight were added and stirred at room temperature for 30 minutes to prepare a base coating agent. This coating agent was applied to the surface of a commercially available unstretched polyethylene terephthalate film (abbreviated as “PET”) having a thickness of 200 μm so that the weight after drying was 5.0 g/m ² using a bar coater #8. Then, it was heated and dried in an oven at 120° C. for 10 seconds to evaporate toluene, thereby forming a base layer on the base film.
(2) Preparation and coating of water repellent coating liquid Hydrophobic oxide fine particles (product name “AEROSIL R812S” manufactured by Evonik Degussa Co., Ltd., BET specific surface area: 220 m ² /g, average primary particle diameter: 96.5 mL of ethanol): (7 nm) was added and stirred at room temperature for 30 minutes to prepare a water repellent coating liquid. This coating solution was applied to the surface of the underlayer prepared above using a bar coater #3 so as to have a weight of 0.5 g/m ² after drying, followed by heating and drying in an oven at 100° C. for 10 seconds. Then, the functional layer was formed by evaporating ethanol. In this way, a resin sheet as a starting material was obtained.
(3) Thermoforming of resin-based sheet A container (food tray) was produced by thermoforming the obtained resin-based sheet. Thermoforming was carried out using a hot plate vacuum pressure molding machine. As this molding machine, "HPT12-400" manufactured by Wakisaka Engineering Co., Ltd. was used. Mold set temperature 138° C., molding air pressure: 0.4 MPa, mold release pressure: 0.1 MPa, heating air pressure: 0.1 MPa, heating air pressure time: 2 seconds, heating vacuum time: 2 seconds, molding air pressure time: 3 Seconds, molding vacuum time: 3 seconds Molding time: 1 second.
The molding method was performed according to the setting conditions of the molding machine. First, a resin sheet was set between the hot plate having the ventilation holes and the molding die (female mold) with the adhesion prevention layer facing the hot plate. Next, fix the heat plate and the resin sheet with a clamp, push the resin sheet from the molding die side with compressed air, and at the same time pull in the resin sheet from the heat plate with a vacuum and push the resin sheet to the heat plate. The pad was heated for 2 seconds. After that, at the same time as the resin sheet was pushed in from the hot plate with compressed air, the resin sheet was pulled from the molding die and pressed into the molding die for 3 seconds to transfer the shape of the molding die (female die). In this way, a container as shown in FIG. 2 was produced.

Example 2
A molded container was obtained in the same manner as in Example 1 except that the PET film of 200 μm in “(1) Preparation and coating of base coat agent” of Example 1 was changed to a PET sheet of 400 μm.

Example 3
A molding container was obtained in the same manner as in Example 1 except that the fine particles in “(2) Preparation and coating of water-repellent coating solution” of Example 1 were obtained by the following method. 100 g of a vapor-phase process silica powder (product name “AEROSIL 200” manufactured by Nippon Aerosil Co., Ltd.) having an average primary particle diameter of 12 nm and a BET specific surface area of 200 m ² /g was placed in a reaction tank, and commercially available with stirring under a nitrogen gas atmosphere. The surface-treating agent (500 g) was sprayed and then stirred at 200° C. for 30 minutes and then cooled. Thus, powder of surface-modified silica fine particles (metal oxide composite fine particles) was obtained. As the above-mentioned treatment agent, an aqueous dispersion of a copolymer of polyfluorooctyl methacrylate, 2-N,N-diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate and 2,2′-ethylenedioxydiethyldimethacrylate (solid content concentration: 20 Wt%) was used as the treating agent.

Example 4
The same procedure as in Example 1 was repeated except that the coating substrate was changed from a 200 μm PET film to a 50 μm PET film, and then the anti-adhesion film was laminated to form a multilayer before molding with a hot plate pressure air molding machine. A molded container was obtained. Specifically, a commercially available PET sheet having a thickness of 350 μm is coated with a polyurethane dry laminate adhesive (weight after drying 3.5 g/m ² ; abbreviated as “D”), and the above-mentioned 50 μm PET adhesion preventing surface is applied. The other side was pasted to prepare a base sheet of "350PET/D/50PET/fine particle-containing base resin/hydrophobic oxide fine particles".

Comparative Example 1
A molded container was obtained in the same manner as in Example 1 except that the PET film having a thickness of 200 μm was changed to the PET film having a thickness of 75 μm and the weight of the undercoating agent after drying was set to 12.0 g/m ² .

Comparative example 2
The hydrophobic oxide fine particles were changed from 3.5 g to 0.5 g, ethanol was changed from 96.5 mL to 99.5 mL, and the dry weight was adjusted to 0.1 g/m ^{2 in the} same manner as in Example 1. A molded container was obtained.

Comparative Example 3
A molded container was obtained in the same manner as in Example 1 except that the polymethylmethacrylate beads were changed from "MBX-20" having an average particle diameter of 20 µm to "MBX-30X-5" having an average particle diameter of 5 µm.

Test example 1
Each molded container sample obtained in each Example and Comparative Example was evaluated as follows. Table 1 shows the layer structure of each sample. Table 2 shows the test results.
(1) Confirmation of Molded State The molded state of each molded container sample obtained in Examples and Comparative Examples was visually confirmed. Specifically, check the sides, bottom, and edges of the molding container for cracks, tears, uneven thickness, and warpage, and check whether the molding container can retain the same shape as the molding die. (Shape retention) was confirmed. When there was no defect and the shape retention was good, it was evaluated as “◯”, and when there was the defect and/or there was a problem with the shape retention, it was evaluated as “x”.
(2) Confirmation of anti-adhesion property A micropipette (pipetman P20, manufactured by GILSON) was attached with a micropipette chip (ibis pipette chip, manufactured by Ibis) 40, and pure water was gently added dropwise to a molded container sample. Samples that slantedly slide off the side surface/bottom surface/bottom edge portion were evaluated as “◯”, and samples that partially adhered were evaluated as “x”.
(3) Confirmation of Mitarashi Dumpling Adhesion Commercially available 1 skewer 4 balls x 4 pieces of mitarashi dumplings were prepared and 1 ball was removed from the skewers. This was held with chopsticks, and two rounds were made along the boundary between the bottom surface and the side surface of each molded container sample obtained in Examples and Comparative Examples, and the Mitarashi dumpling was rubbed. Then, the number of mitarashi dumplings attached to the container was counted. Samples having an adhesion number of less than 10 were evaluated as “◯”, and samples having an adhesion number of 10 or more were evaluated as “x” to the extent that the adhesion of the soup dumplings was not noticeable.

As is clear from the above results, the resin container obtained by the production method of the present invention has a shape-retaining property, and also has an effect of preventing adhesion to the container even for contents with high water content and high viscosity. You can see that you can demonstrate.

Claims (5)

A method of manufacturing a container from a resin-based sheet,
(1) A resin-based sheet is a laminate including a) a resin-based substrate film, b) a base layer formed on at least one surface of the resin-based substrate film, and c) a functional layer formed on the base layer. The body,
a) The resin-based substrate film has a thickness of 100 μm or more,
b) the underlayer contains b1) an adhesive resin component and filler particles having an average particle size D50 of 6 to 50 μm, and b2) has a dry weight of 1.0 to 10.0 g/m ² .
c) the functional layer contains c1) at least one kind of hydrophobic fine particles and oleophobic fine particles, and c2) has a dry weight of 0.3 to 10 g/m ² .
(2) A method of manufacturing a resin container, comprising a step of manufacturing the container by thermoforming the resin sheet. The container includes 1) a bottom part, 2) a side wall part rising from the outer circumference of the bottom part, 3) an opening formed from an upper end part of the side wall part, and 4) a flange part extending from the opening part in the container outer peripheral direction, The manufacturing method according to claim 1. The manufacturing method according to claim 1, wherein the resin-based substrate film is at least one of polyethylene terephthalate-based resin, polyolefin-based resin, and polystyrene-based resin. The manufacturing method according to claim 1, wherein the filled particles are resin beads having a melting point of 90 to 350°C. The method according to claim 4, wherein the resin beads have a specific gravity of 0.93 to 1.30.