JP7326814B2 - Liquid-repellent film, liquid-repellent laminate and packaging material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin composition for forming a liquid-repellent layer, and a liquid-repellent film, a liquid-repellent laminate and a packaging material using the same.

2. Description of the Related Art Conventionally, packaging materials have been developed for many products such as foods, beverages, pharmaceuticals, and chemicals, depending on the contents of each product. In particular, as packaging materials for contents such as liquids, semi-solids, and gel-like substances, plastic materials that are excellent in heat-sealing properties, water resistance, oil resistance, gas barrier properties, light weight, flexibility, and design are used. there is

In addition, as a packaging material for contents such as liquids, semi-solids, and gel-like substances, for the purpose of providing higher functionality, plastic laminates in which multiple types of plastic substrates are laminated, paper, metal foil, and inorganic materials are used. A composite laminate of a material or the like and a plastic substrate, and a composite obtained by treating a plastic substrate with a functional composition have been proposed.

As one of the above-mentioned high functions, for example, it has excellent heat-sealing properties, and the function of suppressing the adhesion of contents such as liquids, semi-solids, and gel substances to the inner surface of the packaging material, that is, the function of suppressing the residue inside the package. is required. More specifically, the function of suppressing the residue inside the package includes lid materials for containers such as yogurt, jelly, and syrup; packaging materials for retort foods such as porridge, soup, curry, and pasta sauce; Contents adhere to the inner surface of film materials for storage containers such as pharmaceuticals and other liquids, semi-solids, and gel-like substances. In order to prevent staining due to adhesion and time-consuming work for discharging the contents, it is required that the inner surface has excellent liquid repellency so that the contents hardly adhere to the inner surface and easily slide off.

In response to these demands, Patent Document 1, for example, proposes a water-repellent packaging material in which a silicone resin composition layer containing hydrophobic fine particles such as silicone particles is provided on the inner surface of the packaging material. In addition, Patent Document 2 proposes a packaging material having a resin layer containing spherical silicon as the innermost layer and having water repellency and releasability for contents.

JP 2013-23224 A JP-A-8-337267

Polyolefin resins such as polyethylene and polypropylene are used as the material for the resin layer on the inner surface of the packaging material as a material that imparts functions such as heat sealability, heat resistance and impact resistance. However, even when the above-described silicone particles are added to the polyolefin resin to impart liquid repellency, aggregation of the silicone particles within the resin layer and release of the silicone particles from the resin layer are likely to occur, resulting in poor packaging. The effect of suppressing the adhesion of contents to the inner surface of the material was not always sufficient.

The present invention has been made in view of the above-mentioned problems of the prior art, and is capable of forming a liquid-repellent layer having excellent heat-sealing properties and excellent liquid-repellent properties that prevent contents from adhering and easily slide off. An object of the present invention is to provide a resin composition, and a liquid-repellent film, a liquid-repellent laminate and a packaging material using the same.

In order to achieve the above object, the present invention includes (A) a polyolefin resin and (B) a polyether/polyolefin copolymer, and the content of (B) the polyether/polyolefin copolymer is Provided is a liquid-repellent layer-forming resin composition having a solid content of 0.5 to 30% by mass based on the total solid content of the layer-forming resin composition.

According to the liquid-repellent layer-forming resin composition, (A) a polyolefin resin and (B) a polyether/polyolefin copolymer are included, and the content of the (B) polyether/polyolefin copolymer is Based on the total solid content of the liquid layer-forming resin composition, the solid content is 0.5 to 30% by mass, so that excellent heat-sealing properties and excellent liquid repellency that the contents are difficult to adhere and easily slide down can be achieved. It is possible to form a liquid-repellent layer having Here, (A) polyolefin resin and (B) polyether/polyolefin copolymer are used in combination, and the content of (B) polyether/polyolefin copolymer is the same as that of the liquid-repellent layer-forming resin composition. Based on the total solid content, the present inventors speculate as follows about the reason why the above effects are exhibited when the content is 0.5 to 30% by mass. That is, the liquid-repellent layer using only the polyolefin resin (A) as the resin composition for forming the liquid-repellent layer and the water-based or oil-based material, which is the content, tend to be charged with opposite charges, which causes electrostatic action. The content may easily adhere to the liquid-repellent layer due to the liquid-repellent layer. On the other hand, when (B) polyether/polyolefin copolymer is used in addition to (A) polyolefin resin as the liquid-repellent layer-forming resin composition, Presumably, the presence of the ether group in the liquid-repellent layer can suppress charging of the liquid-repellent layer, and can suppress the adhesion of contents to the liquid-repellent layer. As a result, the liquid-repellent layer can obtain a high liquid-repellent property that makes it difficult for the contents to adhere and easily slide off. In addition, when the content contains an oily component, by using (B) a polyether/polyolefin copolymer in addition to (A) the polyolefin resin, swelling of the liquid-repellent layer due to the oily component can be suppressed, and the content associated with the swelling can be suppressed. Remaining objects can be suppressed. In addition, the content of the polyether/polyolefin copolymer (B) is 0.5 to 30% by mass based on the total solid content of the liquid-repellent layer-forming resin composition, so that the liquid-repellent layer is formed. The layer has excellent heat-sealing properties, and has excellent liquid repellency to prevent contents from adhering to the layer and easily slip off.

In the liquid-repellent layer-forming resin composition, (A) the polyolefin resin and (B) the polyolefin portion of the polyether/polyolefin copolymer are incompatible, and (A) the portion compatible with the polyolefin resin and ( B) It may further contain (C) a compatibilizer having a site that is compatible with the polyether/polyolefin copolymer. Since the liquid-repellent layer-forming resin composition contains (C) a compatibilizer, the dispersibility of (B) the polyether/polyolefin copolymer is improved, so that the formed liquid-repellent layer can be formed more efficiently. Liquid repellency can be imparted. In addition, since the interfacial adhesion between (A) the polyolefin resin and (B) the polyether/polyolefin copolymer can be improved, the heat sealability of the obtained liquid-repellent laminate is further improved.

The present invention also provides a liquid-repellent film having a liquid-repellent layer formed using the resin composition for forming a liquid-repellent layer of the present invention. According to such a liquid-repellent film, by including the liquid-repellent layer formed by using the resin composition for forming a liquid-repellent layer of the present invention, the heat-sealing property is excellent and the liquid-repellent layer retains the contents. Hard to stick and easy to slide off. Moreover, the liquid-repellent film can exhibit good liquid repellency not only to water and oil, but also to oil-in-water dispersion type contents such as curry and pasta sauce.

The liquid-repellent film may further include one or more resin layers provided on one main surface of the liquid-repellent layer. By forming the liquid-repellent film into a multi-layered structure including a resin layer other than the liquid-repellent layer, it becomes possible to impart further functionality (heat resistance, impact resistance, etc.) in addition to the liquid repellency. In addition, it is possible to reduce the thickness of the liquid-repellent layer and reduce the cost.

When the liquid-repellent film has a resin layer other than the liquid-repellent layer, the melting point T ₁ (° C.) of the polyolefin resin (A) in the liquid-repellent layer and the liquid-repellent layer among the one or more resin layers The melting point T ₂ (° C.) of the resin contained in the resin layer in contact with may satisfy the relationship of T ₁ <T ₂ . By satisfying the above relationship, from the viewpoint of crystallinity, the (B) polyether/polyolefin copolymer in the liquid-repellent layer can be suppressed from migrating to the second resin layer, and the liquid-repellent layer surface ( B) Since uneven distribution of the polyether/polyolefin copolymer can be improved, liquid repellency tends to be further improved.

The present invention also provides a liquid-repellent laminate comprising a substrate and the liquid-repellent film of the present invention provided on the substrate, wherein the liquid-repellent layer is disposed on at least one outermost surface. provide the body According to such a liquid-repellent laminate, since the liquid-repellent film of the present invention is provided, the heat-sealing property is excellent, and contents are less likely to adhere to the liquid-repellent layer and easily slide off. Further, by laminating the liquid-repellent film on a substrate having a desired function, the liquid-repellent laminate can be imparted with functions such as mechanical strength, barrier properties, and light-shielding properties.

The present invention also provides a packaging material formed using the liquid-repellent laminate of the present invention. Such a packaging material is formed using the liquid-repellent laminate of the present invention, so that it is excellent in heat-sealing properties, and contents are less likely to adhere to the liquid-repellent layer and easily slip off.

The packaging material may be used for applications where heat treatment at 80° C. or higher is performed. According to the packaging material according to the present embodiment, even when used for such applications, it has excellent heat-sealing properties, and even after heat treatment, the contents are less likely to adhere to the inner surface of the packaging material and easily slide down. .

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a resin composition capable of forming a liquid-repellent layer having excellent heat-sealability and excellent liquid-repellent properties to which contents are less likely to adhere and easily slip off, and liquid-repellent properties using the same. Films, liquid-repellent laminates and packaging materials can be provided.

1 is a schematic cross-sectional view of a liquid-repellent laminate according to one embodiment of the present invention; FIG. 1 is a schematic cross-sectional view of a liquid-repellent laminate according to one embodiment of the present invention; FIG. It is a schematic diagram explaining the liquid-repellent evaluation method of a liquid-repellent laminated body. It is a schematic diagram explaining the liquid-repellent evaluation method of a liquid-repellent laminated body.

Preferred embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant explanations are omitted. Also, the dimensional ratios in the drawings are not limited to the illustrated ratios.

In the present specification, liquid repellency means the property of repelling liquid to prevent it from adhering to the liquid repellent layer, and the ability to quickly slide off the liquid adhering to the liquid repellent layer and prevent it from remaining in place (does not maintain the adhered state). ) include nature.

[Liquid-repellent laminate]
The liquid-repellent laminate according to the present embodiment includes a base material and a liquid-repellent film provided on the base material, and has a structure in which a liquid-repellent layer is disposed on at least one outermost surface. is. 1 and 2 are schematic cross-sectional views of the liquid-repellent laminate according to this embodiment. In the liquid-repellent laminate according to the present embodiment, a liquid-repellent film 10 composed of a liquid-repellent layer 11 and a base material 14 are bonded together with an adhesive 13 interposed therebetween, like the liquid-repellent laminate 1 shown in FIG. It may have a laminated structure. Further, the liquid-repellent laminate according to the present embodiment, like the liquid-repellent laminate 2 shown in FIG. 14 may have a laminated structure with an adhesive 13 interposed therebetween. When the liquid-repellent film 10 includes the second resin layer 12 , the liquid-repellent film 10 is based on the second resin layer 12 such that the liquid-repellent layer 11 is the outermost surface of the liquid-repellent laminate 2 . It is arranged so as to face the material 14 .

<Liquid Repellent Layer 11>
The liquid repellent layer 11 is a layer having liquid repellency. The liquid-repellent layer 11 may be a layer capable of exhibiting heat-sealing properties by heating. Here, liquid repellency is a concept that includes both water repellency and oil repellency. Specifically, liquid repellency to liquid, semi-solid, or gel-like aqueous or oily materials. is. Aqueous or oily materials include water, oil, yogurt, jelly, pudding, syrup, porridge, soup, curry, foods such as pasta sauce, detergents such as hand soap and shampoo, pharmaceuticals, cosmetics, chemicals, and the like. . The heat-sealability is, for example, the property of being heat-sealable under the conditions of 100 to 200° C., 0.1 to 0.3 MPa, and 1 to 3 seconds. The heat-sealing conditions can be easily changed according to the conditions required for heat-sealing the liquid-repellent laminate.

The thickness of the liquid-repellent layer 11 is preferably 0.1 to 100 μm, more preferably 1 to 70 μm, even more preferably 3 to 50 μm, particularly preferably 5 to 30 μm. When the thickness of the liquid-repellent layer 11 is at least the above lower limit, there is a tendency that good liquid-repellency and heat-sealability can be easily obtained. On the other hand, when the thickness is equal to or less than the above upper limit, the thickness of the entire liquid-repellent laminate can be reduced.

The surface resistance value of the liquid-repellent layer 11 may be 1.0×10 ¹⁴ Ω/□ or less, preferably 1.0×10 ¹² Ω/□ or less, and 1.0×10 ¹⁰ Ω/□ or less. The following are more preferable. When the surface resistance value of the liquid-repellent layer 11 is 1.0×10 ¹⁴ Ω/□ or less, it becomes difficult for positively charged contents to adhere to the liquid-repellent layer 11 due to electrostatic force. Excellent liquid repellency. Since the oil-based material heated to 80° C. or higher is positively charged, the above effect is particularly pronounced when the content is an oil-based material and the packaging material is used for heat treatment at 80° C. or higher. . The surface resistance value of the liquid-repellent layer 11 was measured using Hiresta (Mitsubishi Chemical Analytic) in accordance with JISK6911 under conditions of an applied voltage of 1000 V, a measurement time of 5 minutes, a temperature of 23° C., and a humidity of 50% RH. point to

The liquid-repellent layer 11 can be formed using a liquid-repellent layer-forming resin composition containing the following components. The resin composition for forming a liquid-repellent layer will be described below.

<Resin composition for liquid-repellent layer formation>
A resin composition for forming a liquid-repellent layer according to one embodiment of the present invention comprises (A) a polyolefin resin (hereinafter also referred to as "component (A)") and (B) a polyether/polyolefin copolymer (hereinafter , also referred to as "(B) component"). Here, the component (B) may or may not be compatible with the component (A). When the component (B) is incompatible with the component (A), the resin composition for forming a liquid-repellent layer according to the present embodiment contains a portion compatible with the component (A) and (B) It may further contain (C) a compatibilizer having a site that is compatible with the component.

((A) polyolefin resin)
Component (A) includes polyethylene, polypropylene, polynorbornene, and the like. Component (A) may be a linear polyolefin from the viewpoint of heat-sealability and strength properties (tensile strength, impact strength, etc.), and the linear polyolefin may be linear or branched. When the liquid-repellent laminate is used as a packaging material that is subjected to heat treatment such as boiling in hot water, such as retort food packaging, it prevents the bag-shaped packaging material from breaking due to heat treatment such as boiling in hot water. Component (A) is preferably polypropylene because it is easy to handle. (A) component can be used individually by 1 type or in combination of 2 or more types.

Examples of polyethylene include low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-α-olefin copolymer, and the like. Examples of α-olefin components include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 4-methyl-1-pentene. The copolymer may be a random copolymer or a block copolymer.

Examples of polypropylene include homopolypropylene, block polypropylene, random polypropylene, modified polypropylene, and copolymers of propylene and α-olefins other than ethylene and propylene (propylene-based copolymers).

Modified polypropylene is obtained by graft-modifying polypropylene with an unsaturated carboxylic acid derivative component derived from, for example, an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, or the like. Modified polypropylene such as hydroxyl-modified polypropylene and acrylic-modified polypropylene can also be used as the polypropylene resin. Examples of the α-olefin component used to obtain the propylene-based copolymer include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl-1-pentene, and the like. can.

((B) polyether/polyolefin copolymer)
The component (B) is a component that imparts liquid repellency to the liquid repellent layer 11 . The (B) component has a polyether portion and a polyolefin portion. (B) component can be used individually by 1 type or in combination of 2 or more types.

The polyether/polyolefin copolymer may be a block copolymer or a random copolymer. From the viewpoint of improving the dispersibility of component (B), the polyether/polyolefin copolymer is preferably a random copolymer.

Examples of monomer components that constitute the polyether portion include ethylene oxide, propylene oxide and tetrahydrofuran. A monomer component can be used individually by 1 type or in combination of 2 or more types.

Monomer components constituting the polyolefin moiety include, for example, olefins having 2 to 30 carbon atoms. The olefin having 2 to 30 carbon atoms is preferably an olefin having 2 to 12 carbon atoms, more preferably propylene and/or ethylene. A monomer component can be used individually by 1 type or in combination of 2 or more types.

The component (B) may have a polyolefin moiety that is compatible with the component (A), or may be incompatible (non-compatible). However, when using component (B) whose polyolefin moiety is incompatible with component (A), it is preferable to use the following compatibilizing agent (C) together. In addition, when using component (B) whose polyolefin part is incompatible with component (A), there are more options for combining the materials of component (A) and component (B), making it possible to design according to the purpose and application. In addition, there is an advantage that the liquid repellency tends to be more easily improved. For example, when the (A) component is polypropylene, examples of the (B) component in which the polyolefin portion is compatible with the (A) component include those in which the polyolefin portion is polypropylene, and the polyolefin portion is compatible with the (A) component. Examples of the incompatible component (B) include those in which the polyolefin moiety is polyethylene.

The melting point of the component (B) is 130 to 170 when the packaging material formed using the liquid-repellent layer-forming resin composition is used for applications where heat treatment at 80 ° C. or higher is performed (for retort food packaging materials). °C is more preferred.

((C) compatibilizer)
Component (C) is preferably used when using component (B) whose polyolefin moiety is incompatible with component (A). Component (C) is a component having a site compatible with component (A) and a site compatible with component (B). By using the component (C), the compatibility between the component (B) and the component (A) whose polyolefin sites are incompatible with the component (A) can be improved.

The site that is compatible with the component (A) includes a polyolefin structure that is compatible with the component (A), and is preferably a site that has the same polyolefin structure as the component (A). That is, when component (A) has a polyethylene structure, component (C) preferably has a polyethylene structure. When component (A) has a polypropylene structure, component (C) preferably has a polypropylene structure. Further, when the component (A) is a copolymer composed of two or more olefins, the component (C) is a polymer of the same olefin as the main component among the olefins constituting the component (A). It is preferred to have at least a copolymerized structure.

The site that is compatible with the component (B) includes a polyolefin structure that is compatible with the polyolefin site of the component (B), and is preferably a site that has the same type of polyolefin structure as the polyolefin site of the component (B). . That is, when the polyolefin portion of component (B) has a polyethylene structure, component (C) preferably has a polyethylene structure. When the polyolefin portion of component (B) has a polypropylene structure, component (C) preferably has a polypropylene structure. Further, when the polyolefin portion of component (B) has a structure based on a copolymer consisting of two or more olefins such as ethylene-α-olefin copolymer and propylene-α-olefin copolymer, component (C) is It is preferable to have at least a structure obtained by polymerizing or copolymerizing an olefin of the same kind as the olefin constituting the main component among the olefins constituting the copolymer.

Component (C) may be, for example, a block copolymer of ethylene and propylene, or a block copolymer of propylene and ethylene/butylene copolymer. When these components (C) are used, it is preferable to use those having a polyethylene portion as the (A) component and those having a polypropylene portion as the (B) component. In this case, the polyethylene portion of component (A) and the polyethylene portion of component (C) are compatible, and the polypropylene portion of component (B) and the polypropylene portion of component (C) are compatible.

(C) component can be used individually by 1 type or in combination of 2 or more types.

The content of component (A) in the liquid-repellent layer-forming resin composition is preferably 60 to 99.5% by mass, based on the total solid content of the liquid-repellent layer-forming resin composition, and is preferably 62.5%. It is more preferably up to 97.5% by mass, and even more preferably 65 to 95% by mass. When the content of component (A) is at least the above lower limit, good heat-sealability tends to be obtained. On the other hand, when the content of the component (A) is equal to or less than the above upper limit, the content of the component (B) and the component (C), which is used as necessary, increases relatively, so the liquid repellency tends to be improved. Tend.

The content of component (B) in the liquid-repellent layer-forming resin composition is 0.5 to 30% by mass, based on the total solid content of the liquid-repellent layer-forming resin composition, and 0.75 to 27.5% by mass. It is preferably 5% by mass, more preferably 1.0 to 25% by mass. When the content of the component (B) is at least the above lower limit, the liquid repellency tends to be improved. On the other hand, when the content of the component (B) is equal to or less than the above upper limit, there is a tendency that good heat-sealing properties are likely to be obtained.

The total content of components (B) and (C) in the liquid-repellent layer-forming resin composition is 0.5 to 50% by mass based on the total solid content of the liquid-repellent layer-forming resin composition. preferably 0.75 to 47.5% by mass, even more preferably 1.0 to 45% by mass. When the total content of the component (B) and the component (C) is at least the above lower limit, the liquid repellency tends to be improved. On the other hand, when the total content of the components (B) and (C) is equal to or less than the above upper limit, the content of the component (A) relatively increases, so that good heat sealability tends to be obtained. be.

When the liquid-repellent layer-forming resin composition contains component (C), the mass ratio of the content of component (C) to the content of component (B) (mass of component (C)/mass of component (B)) may be 0.01 to 50, preferably 0.04 to 30, more preferably 0.05 to 20, even more preferably 0.05 to 15. When this content ratio is at least the above lower limit, the component (B) can be sufficiently dispersed in the liquid-repellent layer, and there is a tendency that better liquid repellency can be obtained. On the other hand, when the content ratio is equal to or less than the above upper limit, there is a tendency that component (B) is prevented from being coated with excess component (C), and better liquid repellency can be obtained. In addition, even if component (C) is added so that the content ratio exceeds the above upper limit, component (B) will not disperse further, and the effect of improving liquid repellency tends to be lost.

The liquid-repellent layer-forming resin composition may contain other additives, if necessary, to the extent that the liquid-repellent property is not impaired. Other additives include, for example, flame retardants, slip agents, antiblocking agents, antioxidants, light stabilizers, tackifiers, and the like.

The liquid-repellent layer 11 can be formed by forming a film from the liquid-repellent layer-forming resin composition.

<Second resin layer 12>
The second resin layer 12 is a layer provided between the liquid-repellent layer 11 and the substrate 14 in order to improve heat sealability, heat resistance, impact resistance, oxygen/water vapor barrier properties, and the like. By further including the second resin layer in the liquid-repellent film, it becomes possible to impart further functionality (heat resistance, impact resistance, etc.) in addition to the heat sealability and liquid repellency. In addition, since the liquid-repellent layer can be made thinner and the total amount of component (B) contained in the liquid-repellent layer can be reduced, cost reduction is also possible. The second resin layer 12 preferably contains a heat-sealable thermoplastic resin.

The thermoplastic resin used for the second resin layer 12 is not particularly limited, but polyolefin resin, ethylene-α,β unsaturated carboxylic acid copolymer or its esterified product or ionic crosslinked product, ethylene-vinyl acetate copolymer. or saponified products thereof, polyvinyl acetate or saponified products thereof, polycarbonate resins, thermoplastic polyester resins, ABS resins, polyacetal resins, polyamide resins, polyphenylene oxide resins, polyimide resins, polyurethane resins, polylactic acid resins, furan resins, and silicone resins etc. These thermoplastic resins can be used singly or in combination of two or more.

The thermoplastic resin used for the second resin layer 12 preferably contains a polyolefin resin, since heat sealability, heat resistance, and impact resistance are likely to be improved. As the polyolefin resin, the same one as the component (A) used for the liquid-repellent layer 11 can be used.

When the second resin layer 12 is in contact with the liquid-repellent layer 11, the melting point T ₁ (°C) of the component (A) in the liquid-repellent layer 11 and the melting point of the thermoplastic resin in the second resin layer 12 T ₂ (° C.) preferably satisfies the relationship of T ₁ <T ₂ . By satisfying the above relationship, the component (B) in the liquid-repellent layer 11 can be suppressed from migrating to the second resin layer 12 from the viewpoint of crystallinity, and the component (B) to the surface of the liquid-repellent layer 11 can be suppressed. can improve the uneven distribution or bleed-out efficiency, so there is a tendency that the liquid repellency can be further improved. From the same point of view, the melting point _T2 is preferably higher than the melting point _T1 by 1°C or more, more preferably by 3°C or more.

Here, the melting point _T1 is the melting point of the component (A) measured in the liquid-repellent layer 11 using the liquid-repellent layer 11 as a measurement sample. Similarly, the melting point _T2 is the melting point of the resin measured in the second resin layer 12 using the second resin layer 12 as a measurement sample. The melting point _T1 indicates the melting point of the polyolefin resin that melts at the lowest temperature in the liquid-repellent layer 11 when the liquid-repellent layer 11 contains two or more polyolefin resins having different melting points as the component (A). Because it is affected by other polyolefin resins, it differs from the melting point measured for polyolefin resin alone. The melting point T1 of the component (A) in the liquid-repellent layer ₁₁ and the melting point _T2 of the resin in the second resin layer 12 are measured by a thermal analyzer (for example, TA7000 manufactured by Hitachi High-Tech Science Co., Ltd.). be able to.

The thickness of the second resin layer 12 can be appropriately set according to the end use of the product using the present liquid-repellent layer-forming resin composition. The thickness of the second resin layer 12 is, for example, preferably 0.1 to 300 μm, more preferably 1 to 200 μm, even more preferably 5 to 150 μm, and 10 to 100 μm. is particularly preferred.

<Liquid repellent film 10>
A liquid-repellent film 10 having liquid-repellency is formed by the above-described liquid-repellent layer 11 single layer or two layers of the liquid-repellent layer 11 and the second resin layer 12 . The liquid-repellent film 10 is formed so as to cover part or all of the surface of the substrate 14 . Depending on the application, the liquid-repellent film 10 may be used alone without being laminated with the base material 14 .

The liquid-repellent film 10 may further include one or more resin layers other than the liquid-repellent layer 11 and the second resin layer 12 . The composition of the other resin layer may be the same as or different from the composition of the second resin layer 12 .

<Base material 14>
The base material 14 is not particularly limited as long as it can serve as a support, and examples thereof include paper, resin film, metal foil, and the like. Examples of paper include woodfree paper, special woodfree paper, coated paper, art paper, cast-coated paper, imitation paper, and kraft paper. Examples of resin films include polyolefins (e.g., polyethylene (PE), polypropylene (PP), etc.), acid-modified polyolefins, polyesters (e.g., polyethylene terephthalate (PET), etc.), polyamides (PA), polyvinyl chloride (PVC), cellulose acetate, A film containing at least one type of cellophane resin is included. This film may be a stretched film or a non-stretched film. Examples of metal foil include aluminum foil and nickel foil. The base material 14 may be a laminate of a plurality of base materials made of different materials.

The thickness of the base material 14 is not particularly limited, and can be appropriately adjusted depending on the application.

Examples of a method for bonding the base material 14 and the liquid-repellent film 10 include, but are not limited to, a lamination method using an adhesive and a lamination method using a heat treatment, as described below.

(Lamination method with adhesive)
As a lamination method using an adhesive, various known lamination methods such as dry lamination, wet lamination, and non-solvent lamination can be used. Examples of the adhesive 13 used in these lamination methods include the following.

<Adhesive 13>
The adhesive 13 bonds the liquid-repellent film 10 and the substrate 14 together. Examples of the adhesive 13 include a polyurethane resin obtained by reacting a base material such as polyester polyol, polyether polyol, acrylic polyol, or carbonate polyol with a difunctional or higher isocyanate compound. The various polyols mentioned above can be used singly or in combination of two or more.

For the purpose of promoting adhesion, the adhesive 13 may further contain a carbodiimide compound, an oxazoline compound, an epoxy compound, a phosphorus compound, a silane coupling agent, or the like in addition to the polyurethane resin described above.

Moreover, according to the performance required for the adhesive 13, the polyurethane resin described above may be blended with various other additives and stabilizers.

The thickness of the adhesive 13 is not particularly limited, but is preferably 1 to 10 μm, more preferably 3 to 7 μm, from the viewpoint of obtaining desired adhesive strength, conformability, workability, and the like.

(Lamination method by heat treatment)
As a lamination method by heat treatment, the following methods are roughly exemplified.
(1) A method of extrusion laminating the liquid-repellent film 10 formed in advance onto the substrate 14 together with an adhesive resin.
(2) A method of extrusion laminating a resin layer and an adhesive resin constituting the liquid-repellent film 10 onto the substrate 14 .
(3) A method of bonding the laminated base material obtained by the above method (1) or (2) by further heating and pressurizing with a hot roll.
(4) A method of storing the laminated base material obtained by the above method (1) or (2) in a high-temperature atmosphere, or passing it through a drying/baking furnace in a high-temperature atmosphere.

Examples of the adhesive resin used in the lamination method by heat treatment include acid-modified polyolefin. In the above method, the substrate 14 and the liquid-repellent film 10 are laminated by extrusion lamination. It is also possible to laminate the liquid-repellent film 10 by heat treatment after coating and forming on 14 .

In addition, it is possible to provide an adhesive primer (anchor coat) on the base material 14, and the materials thereof include polyester, polyurethane, polyallylamine, polyethyleneimine, polybutadiene, and ethylene-vinyl acetate copolymer. It is possible to use coalescence, chlorine-vinyl acetate, etc., and if necessary, the various curing agents and additives described above that can be used as the adhesive 13 may be blended.

In the liquid-repellent laminate according to the present embodiment, the liquid-repellent laminate is formed in the shape of a bag so that the liquid-repellent layer is on the inner surface. The amount of oil swelling per unit area of the liquid-repellent laminate is 1.0 mg/cm ² or less after being subjected to heat and pressure treatment with water vapor under conditions of 121° C., pressure of 0.2 MPa, and 30 minutes. preferable. When the oil swelling amount measured in this way is 1.0 mg/cm ² or less, the liquid-repellent laminate can have more excellent liquid repellency, and the residual liquid after the contents are discharged. The amount can be further reduced. From the same point of view, the oil swelling amount is more preferably 0.95 mg/cm ² or less. On the other hand, the liquid-repellent layer may swell to some extent with oils and fats from the viewpoint of improving the slideability of the contents, and the oil swelling amount may be 0.5 mg/cm ² or more.

[Packaging material]
The packaging material according to this embodiment is formed using the liquid-repellent laminate described above. Specific examples of packaging materials include container lids for yogurt, jelly, syrup, and the like, and retort pouches for porridge, soup, curry, pasta sauce, and the like. By forming the packaging material so that the liquid-repellent layer is arranged on the inner surface (contents side) of the packaging material, it is possible to suppress the adhesion and residue of contents such as liquids, semi-solids, and gel-like substances on the inner surface of the packaging material. can do. In addition, in a bag-shaped packaging material such as a retort food packaging material, blocking between the innermost layers of the packaging material may make it difficult to discharge the contents, but according to the packaging material according to the present embodiment, , the liquid-repellent layers, which are the innermost layers, are unlikely to block each other, and the contents can be discharged efficiently.

The packaging material may be used for applications where heat treatment at 80° C. or higher is performed. Specifically, it may be used for packaging materials such as retort food packaging materials that are subjected to heat treatment such as boiling in hot water. According to the packaging material according to the present embodiment, even when used for such purposes, it is possible to prevent the contents from adhering or remaining on the inner surface of the packaging material even after the heat treatment.

[container]
The container according to the present embodiment is a container having at least the inner surface (on the content side) a liquid-repellent layer formed using the liquid-repellent layer-forming resin composition described above. Specific examples of containers include storage containers for liquids such as chemicals and pharmaceuticals, semi-solids, and gel-like substances, and bottles for containing hand soaps, shampoos, and the like. By forming the container so that the liquid-repellent layer is arranged on the inner surface of the container (on the content side), it is possible to suppress the adhesion and residue of contents such as liquids, semi-solids, and gel-like substances on the inner surface of the container. can.

EXAMPLES The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples.

<Preparation of resin composition for forming liquid-repellent layer>
[Examples 1 to 24 and Comparative Examples 1 to 7]
The materials shown in Tables 1 and 2 were prepared and mixed at the ratios shown in Tables 1 and 2 to prepare a resin composition for forming a liquid-repellent layer. Abbreviations in Tables 1 and 2 are as follows.
b-PP1: block polypropylene resin (propylene-ethylene block copolymer, trade name “Novatec”, melting point 135-165°C, manufactured by Japan Polypropylene Corporation)
b-PP2: block polypropylene resin (propylene-ethylene block copolymer, trade name “Novatec”, melting point 145-170°C, manufactured by Japan Polypropylene Corporation)
LLDPE: Linear low-density polyethylene resin (trade name “Evolue”, melting point 116°C, manufactured by Prime Polymer Co., Ltd.)
B1: Polyether/polyolefin copolymer (melting point 135° C., surface resistance 1.0×10 ⁸ Ω/□)
PP-PE: block copolymer of propylene and ethylene PP-Et/Bu: block copolymer of propylene and ethylene/butylene copolymer

<Preparation of liquid-repellent laminate>
[Examples 1 to 4 and 12 to 20 and Comparative Examples 2 to 7]
Using a three-layer co-extrusion machine, the liquid-repellent layer-forming resin composition was extruded into a film to obtain a liquid-repellent film having a liquid-repellent layer with a thickness of 60 μm. The resulting liquid-repellent film and a 38 μm-thick PET film (trade name “EMBRET”, manufactured by Unitika Ltd.) as a substrate were dried using a polyurethane adhesive (manufactured by Mitsui Chemicals, Inc.). It was laminated and aged at 50° C. for 4 days to obtain a liquid-repellent laminate.

[Examples 5 to 11 and 21 to 24 and Comparative Example 1]
Raw materials shown in Tables 1 and 2 were prepared and used as a resin composition for forming a second resin layer. Using a three-layer co-extrusion machine, the liquid-repellent layer-forming resin composition and the second resin layer-forming resin composition are co-extruded to form a film, forming a liquid-repellent layer with a thickness of 15 μm and a second resin composition with a thickness of 45 μm. A liquid-repellent film consisting of a resin layer was obtained. The second resin layer of the obtained liquid-repellent film and a PET film with a thickness of 38 μm (trade name “EMBRET”, manufactured by Unitika Ltd.) as a base material are bonded together with a polyurethane adhesive (Mitsui Chemicals, Inc. (manufactured) to obtain a liquid-repellent laminate.

Tables 1 and 2 show the melting point T ₁ (°C) of the resin that is the component (A) measured in the liquid-repellent layer, and the melting point T of the resin that is the component (A) used in the second resin layer. ₂ (°C). The melting point _T1 of the component (A) in the liquid-repellent layer and the melting point _T2 of the resin in the second resin layer were measured with a thermal analyzer (TA7000, manufactured by Hitachi High-Tech Science Co., Ltd.).

(Evaluation of liquid repellency)
<Residual liquid evaluation without retort treatment>
[Examples 12 to 24 and Comparative Examples 3 to 7]
The obtained liquid repellent laminate was evaluated for liquid repellency by the method shown in FIG. First, two samples 100 were prepared by cutting the liquid-repellent laminate into a size of 150 mm long and 138 mm wide. Two samples 100 are stacked so that the liquid-repellent layer of each is on the inside, and one vertical edge and two horizontal edges are sealed with a heat sealer at 190° C. and 0.03 MPa for 2 seconds. The pouch was heat-sealed over a width of 10 mm to form a sealed portion 51, and a pouch having one longitudinal end open was produced (see FIG. 3(a)). Next, 100 g of salad oil 54 was injected from the opening of the pouch (see (b) of FIG. 3). After that, the pouch was then turned upside down, and the spout was held at an angle of 45° from the horizontal for 30 seconds, the salad oil 54 was discharged into the container 56, and the discharged amount was weighed by the scale 57 (Fig. 3(c)). ). From the weighed discharge amount, the residual liquid amount (%) was determined by the following formula.
Residual liquid amount (%) = {(100-discharged amount) / 100} x 100
The measurement was performed three times, and the residual liquid was evaluated from the average residual liquid amount of the three times according to the following evaluation criteria. Tables 1 and 2 show the residual liquid amount and the residual liquid evaluation results.
◎: Average residual liquid amount is less than 2.0% ○: Average residual liquid amount is 2.0% or more and less than 2.5% △: Average residual liquid amount is 2.5% or more and less than 3.5% ×: Average residual liquid amount Liquid volume is 3.5% or more

<Residual liquid evaluation with retort treatment>
[Examples 1 to 11 and Comparative Examples 1 and 2]
The obtained liquid repellent laminate was evaluated for liquid repellency by the method shown in FIG. First, two samples 200 were prepared by cutting the liquid-repellent laminate into a size of 150 mm long and 138 mm wide. Two samples 200 were stacked so that the liquid-repellent layer of each was on the inside, and one vertical edge and two horizontal edges were sealed with a heat sealer at 190° C. and 0.03 MPa for 2 seconds. The pouch was heat-sealed over a width of 10 mm to form a sealed portion 151, and a pouch having one longitudinal end open was produced (see FIG. 4(a)). Next, 180 g of oil-in-water dispersion type liquid 154 (trade name “Boncurry Gold medium hot”, lipid content 7.0 g / 180 g, manufactured by Otsuka Foods Co., Ltd.) was injected from the opening of the pouch (Fig. 4 (b )). Thereafter, the opening was heat-sealed with a heat sealer over a width of 10 mm under the conditions of 190° C., 0.03 MPa, and 2 sec to form a sealed portion 151, thereby sealing the pouch (see FIG. 4(c)).

After the sealed pouch is put into a high-temperature and high-pressure cooking sterilizer (manufactured by Hitachi Capital Co., Ltd.), retort treatment is performed at 121 ° C. for 30 minutes with high-temperature steam at a pressure of 0.2 MPa, and the sealed pouch is heated at 100 ° C. It was boiled in hot water for 5 minutes. Immediately after the above treatment, the top of the sealed pouch was cut to form a spout (see Figure 4(d)). Next, the pouch was turned upside down and held for 10 seconds with the spout tilted 45° from the horizontal surface, the oil-in-water dispersion liquid 154 was discharged into the container 56, and the discharged amount was weighed by the scale 57 (( e)). From the weighed discharge amount, the residual liquid amount (%) was determined by the following formula.
Residual liquid amount (%) = {(180-discharged amount) / 180} x 100
The measurement was performed three times, and the residual liquid was evaluated from the average residual liquid amount of the three times according to the following evaluation criteria. Tables 1 and 2 show the residual liquid amount and the residual liquid evaluation results.
◎: Average residual liquid amount is less than 6.5% ○: Average residual liquid amount is 6.5% or more and less than 8.0% △: Average residual liquid amount is 8.0% or more and less than 10.0% ×: Average residual liquid amount Liquid volume is 10.0% or more

<Appearance evaluation>
[Examples 1 to 24 and Comparative Examples 1 to 7]
In the evaluation of the remaining liquid, the discharge behavior of the liquid when discharged from the pouch was visually observed, and the external appearance was evaluated according to the following evaluation criteria. The results are shown in Tables 1 and 2.
⊚: A state in which the liquid slides cleanly is observed, and there is almost no adhesion to the film.
◯: A liquid slides down, and there is little adhesion to the film.
Δ: The liquid appears to slide down, but adheres to the film.
x: A large amount of the liquid adhered to the film without any sign of sliding down.

(Evaluation of heat sealability)
[Examples 1 to 24 and Comparative Examples 1 to 7]
Two samples were prepared by cutting the liquid-repellent laminate into a size of 50 mm long and 15 mm wide. The two samples were stacked so that the liquid-repellent layer of each was on the inside, and heat-sealed with a heat sealer under the conditions of 190° C., 0.2 MPa, and 1 second over a length of 50 mm×width of 15 mm to form a sealed portion. Next, using a peel tester (AGS-X manufactured by Shimadzu Corporation), the peel strength was measured at a peel angle of 180 degrees and a peel speed of 300 mm/min. The peel strength was evaluated according to the following evaluation criteria. The results are shown in Tables 1 and 2. In Tables 1 and 2, it is simply referred to as "sealability".
A: The seal strength is 40 N/15 mm or more.
○: The seal strength is 30 N/15 mm or more and less than 40 N/15 mm.
Δ: The seal strength is 20 N/15 mm or more and less than 30 N/15 mm.
x: The seal strength is less than 20 N/15 mm.

(Measurement of surface resistance)
The surface resistance value of the liquid-repellent layer of the liquid-repellent laminate was measured. The surface resistance value was measured according to JISK6911 using Hiresta (Mitsubishi Chemical Analytic). The measurement conditions were an applied voltage of 1000 V, a measurement time of 5 minutes, a temperature of 23° C., and a humidity of 50% RH.

As is clear from the results shown in Tables 1 and 2, according to the liquid-repellent laminates of Examples 1-24, less residual liquid is present than the liquid-repellent laminates of Comparative Examples 1-5. Also, it was confirmed that the liquid slid down inside the pouch, which confirmed that the liquid repellency could be improved. Moreover, it was confirmed that the liquid-repellent laminates of Examples 1 to 24 are superior in heat-sealability as compared with the liquid-repellent laminates of Comparative Examples 6 and 7.

The liquid-repellent laminates of Examples 5 to 11 and 21 to 24 are excellent in heat resistance and impact resistance due to the second resin layer.

DESCRIPTION OF SYMBOLS 1, 2... Liquid-repellent laminate 10... Liquid-repellent film 11... Liquid-repellent layer 12... Second resin layer 13... Adhesive 14... Base material 51, 151... Seal part 54... Salad oil 154 Oil-in-water dispersion type liquid 56 Container 57 Scale 100, 200 Evaluation sample of liquid-repellent laminate.

Claims (10)

A packaging material formed using a liquid-repellent laminate comprising a substrate and a liquid-repellent layer formed using a resin composition provided on the substrate,
In the liquid-repellent laminate, the liquid-repellent layer is arranged on at least one outermost surface,
The resin composition comprises (A) a polyolefin resin and (B) a polyether/polyolefin copolymer,
The content of the polyether/polyolefin copolymer (B) in the resin composition is 0.5 to 30% by mass based on the total solid content of the resin composition ,
the polyether portion of the (B) polyether/polyolefin copolymer is derived from at least one monomer component selected from the group consisting of ethylene oxide, propylene oxide and tetrahydrofuran,
A packaging material used for heat treatment at 80°C or higher . (A) the polyolefin resin and the polyolefin portion of the (B) polyether/polyolefin copolymer are incompatible,
The resin composition further comprises (C) a compatibilizer having a site that is compatible with the (A) polyolefin resin and a site that is compatible with the (B) polyether/polyolefin copolymer,
The (A) polyolefin resin is polypropylene,
The polyolefin moiety of the (B) polyether/polyolefin copolymer is polyethylene,
The packaging material according to claim 1 , wherein the (C) compatibilizer has a polyethylene structure and a polypropylene structure . (A) the polyolefin resin and the polyolefin portion of the (B) polyether/polyolefin copolymer are incompatible,
The resin composition further comprises (C) a compatibilizer having a site that is compatible with the (A) polyolefin resin and a site that is compatible with the (B) polyether/polyolefin copolymer,
The (A) polyolefin resin is polyethylene,
The polyolefin moiety of the (B) polyether/polyolefin copolymer is polypropylene,
2. The packaging material of claim 1, wherein (C) the compatibilizer has a polyethylene structure and a polypropylene structure. The packaging material according to any one of claims 1 to 3 , wherein the liquid-repellent laminate further comprises one or more resin layers provided on the main surface of the liquid-repellent layer on the substrate side . The melting point T ₁ (°C) of the (A) polyolefin resin in the liquid-repellent layer and the melting point T ₂ (°C) of the resin contained in the resin layer in contact with the liquid-repellent layer among the one or more resin layers satisfies the relationship T ₁ <T ₂ . A liquid-repellent layer formed using a resin composition, and one or more resin layers provided on one main surface of the liquid-repellent layer,
The resin composition contains (A) a polyolefin resin and (B) a polyether/polyolefin copolymer,
The content of the polyether/polyolefin copolymer (B) in the resin composition is 0.5 to 30% by mass based on the total solid content of the resin composition,
the polyether portion of the (B) polyether/polyolefin copolymer is derived from at least one monomer component selected from the group consisting of ethylene oxide, propylene oxide and tetrahydrofuran,
Melting point T of the (A) polyolefin resin in the liquid-repellent layer ₁ (° C.) and the melting point T of the resin contained in the resin layer in contact with the liquid-repellent layer among the one or more resin layers ₂ (°C) and ₁ <T ₂ A liquid-repellent film that satisfies the relationship of (A) the polyolefin resin and the polyolefin portion of the (B) polyether/polyolefin copolymer are incompatible,
The resin composition further comprises (C) a compatibilizer having a site that is compatible with the (A) polyolefin resin and a site that is compatible with the (B) polyether/polyolefin copolymer,
The (A) polyolefin resin is polypropylene,
The polyolefin moiety of the (B) polyether/polyolefin copolymer is polyethylene,
7. The liquid-repellent film according to claim 6, wherein the (C) compatibilizer has a polyethylene structure and a polypropylene structure. (A) the polyolefin resin and the polyolefin portion of the (B) polyether/polyolefin copolymer are incompatible,
The resin composition further comprises (C) a compatibilizer having a site that is compatible with the (A) polyolefin resin and a site that is compatible with the (B) polyether/polyolefin copolymer,
The (A) polyolefin resin is polyethylene,
The polyolefin moiety of the (B) polyether/polyolefin copolymer is polypropylene,
7. The liquid-repellent film according to claim 6, wherein (C) the compatibilizer has a polyethylene structure and a polypropylene structure. A substrate, and the liquid-repellent film according to any one of claims 6 to 8 provided on the substrate, wherein the liquid-repellent layer is disposed on at least one outermost surface, Liquid-repellent laminate. A packaging material formed using the liquid-repellent laminate according to claim 9 .

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