WO2022097658A1

WO2022097658A1 - Laminate and container

Info

Publication number: WO2022097658A1
Application number: PCT/JP2021/040482
Authority: WO
Inventors: 峻人是澤; 勇人當銘; 康宏中野
Original assignee: 出光ユニテック株式会社
Priority date: 2020-11-06
Filing date: 2021-11-04
Publication date: 2022-05-12
Also published as: TW202233422A

Abstract

Provided is a laminate that at least comprises a surface layer which is formed from a first resin composition containing polyethylene and polypropylene, and a subsurface layer which is adjacent to the surface layer and which is formed from a second resin composition containing polyethylene and polypropylene, wherein the surface of the surface layer on the side opposite from the subsurface layer has an arithmetic mean roughness of not less than 0.5 μm.

Description

Laminates and containers

The present invention relates to a laminate and a container.

Traditionally, laminates have been used in containers for pharmaceuticals, medical products, cosmetics, foods, beverages, industrial parts, electronic parts, etc. In such a laminate, a polyolefin resin is often used as a material having excellent impact resistance. In particular, for containers such as foods and beverages, a laminate that is not easily affected by the heat treatment in the heat sterilization step is preferably used. For example, in Patent Document 1, in a sheet composed of a base material layer and a seal layer, by using a polymer component derived from propylene for the seal layer, excellent blocking resistance, heat seal strength and impact resistance are obtained, and appearance defects due to heat treatment are deteriorated. Techniques for mitigation are described.

Japanese Unexamined Patent Publication No. 2013-71409

However, the laminate described in Patent Document 1 is not used for a container whose opening is facilitated by using, for example, delamination because the delamination property between layers and the edge cutting property of the layer after delamination are low. .. Further, there is no mention of the peelability when the molded containers are overlapped with each other.

Therefore, an object of the present invention is to provide a laminated body and a container which can be easily opened by delamination of the container after molding and can easily peel off the stacked containers after molding.

[1] A surface layer formed of a first resin composition containing polypropylene and polyethylene, and a subsurface layer adjacent to the surface layer and formed of a second resin composition containing polypropylene and polyethylene. A laminate containing at least the surface layer and having an arithmetic average roughness Ra of the surface opposite to the surface layer of the surface layer of 0.5 μm or more.
[2] The laminate according to [1], wherein the first resin composition contains polypropylene in an amount of 80% by mass or more and 99% by mass or less, and polyethylene in an amount of 1% by mass or more and 20% by mass or less.
[3] The laminate according to [1] or [2], wherein the polyethylene contained in the first resin composition has a melting point of 115 ° C. or higher and 140 ° C. or lower.
[4] The laminate according to any one of [1] to [3], wherein the density of polyethylene contained in the first resin composition is 930 kg / m ³ or more.
[5] The laminate according to any one of [1] to [4], wherein the polypropylene contained in the first resin composition is homopolypropylene.
[6] The laminate according to any one of [1] to [5], wherein the first resin composition further contains a nucleating agent.
[7] The laminate according to any one of [1] to [6], wherein the surface layer has a thickness of 5 μm or more and 40 μm or less.
[8] The laminate according to any one of [1] to [7], wherein the second resin composition contains polypropylene in an amount of 15% by mass or more and 58% by mass or less.
[9] The laminate according to any one of [1] to [8], wherein the second resin composition contains at least two types of polyethylene having different melting points from each other.
[10] The laminate according to any one of [1] to [9], wherein the second resin composition contains at least two types of polyethylene having different densities from each other.
[11] The laminate according to any one of [1] to [10], wherein the density of the second resin composition is 900 kg / m ³ or more and 970 kg / m ³ or less.
[12] Further, a first and second base material layer laminated on the side opposite to the surface layer with respect to the lower surface layer, and an oxygen barrier layer laminated between the first and second base material layers. The laminate according to any one of [1] to [11], which comprises.
[13] The laminate according to [12], wherein the oxygen barrier layer contains an ethylene vinyl alcohol resin.
[14] The laminate according to any one of [1] to [13], which has a thickness of 0.2 mm or more and 1.5 mm or less.
[15] A container in which the laminate according to any one of [1] to [14] is formed so that the surface layer is on the inside.
[16] The laminate according to any one of [1] to [14], wherein the second resin composition contains an elastomer.
[17] The laminate according to [16], wherein the content of the elastomer in the second resin composition is 0.5% by mass or more and 16% by mass or less.
[18] The laminate according to [16] or [17], wherein the melt flow rate of the elastomer contained in the second resin composition is 0.5 g / 10 minutes or more and 5 g / 10 minutes or less.
[19] The laminate according to any one of [16] to [18], wherein the elastomer contained in the second resin composition contains an ethylene-α-olefin copolymer.
[20] A container in which the laminate according to any one of [16] to [19] is formed so that the surface layer is on the inside.

According to the above configuration, the resin composition forming the surface layer contains polypropylene, and the resin composition forming the lower surface layer contains polypropylene and polyethylene, so that the surface layer and the lower surface layer are separated from each other. It is easy and the surface layer is easy to break at the edge of the joint region. Further, when the arithmetic average roughness Ra of the surface opposite to the lower surface layer of the surface layer is 0.5 μm or more, it becomes easy to peel off the stacked containers after molding.

It is a schematic sectional drawing which shows the structure of the laminated body which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the example of the container in which the laminated body shown in FIG. 1 is molded.

A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings below. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

In the present specification, the main component of the resin composition forming each layer of the laminate means the resin component having the highest content in the resin composition forming the layer. Therefore, the resin composition may contain other components in addition to the main component. The main component can be confirmed by, for example, the IR method. In the present specification, the content of the components of the resin composition forming each layer of the laminate is expressed in mass% with respect to the entire resin composition forming the layer, unless otherwise specified.

(First Embodiment)
FIG. 1 is a schematic cross-sectional view showing the structure of the laminated body according to the first embodiment of the present invention. As shown in FIG. 1, the laminate 10 has a surface layer 11,

subsurface layers

12, 15 and

base layers

13, 14. Hereinafter, the configuration of each layer will be described. The laminate 10 has a thickness suitable for forming a container as described later, specifically, for example, 0.01 mm or more and 1.8 mm or less, preferably 0.1 mm or more and 1.6 mm or less, more preferably. Is formed with a thickness of 0.2 mm or more and 1.5 mm or less, more preferably 0.25 mm or more and 1.4 mm or less, particularly preferably 0.3 mm or more and 1.2 mm or less, but is not limited to this example. ..

The surface layer 11 is a layer that is joined to the lid body by a heat seal or the like when the laminated body 10 is formed into a container described later. Specifically, the surface layer 11 is formed of a resin composition containing polypropylene as a main component. The resin composition forming the surface layer 11 (hereinafter, also referred to as the first resin composition) preferably contains homopolypropylene (HPP) from the viewpoint of improving the appearance after heating, but other than HPP, it is preferable. , Polypropylene such as random polypropylene (RPP) or block polypropylene (BPP), polyethylene such as high density polyethylene (HDPE) or medium density polyethylene (MDPE), or linear ethylene-α-olefin copolymers and the like may be included. .. Further, the first resin composition may contain a nucleating agent. Specific examples of the nucleating agent include organic carboxylic acid or a metal salt thereof, aromatic sulfonate or a metal salt thereof, an organic phosphoric acid compound or a metal salt thereof, dibenzylidene sorbitol or a derivative thereof, a partial metal salt of loginic acid, and an inorganic substance. Examples thereof include fine particles, imides, amides, quinacridones, quinones or mixtures thereof.

Examples of the metal salt of the organic carboxylic acid include aluminum benzoate, pt-butyl aluminum benzoate, sodium adipate, sodium thiophenecarboxylate, sodium pyrolecarboxylate and the like.
Examples of dibenzylidene sorbitol or a derivative thereof include dibenzylidene sorbitol, 1,3: 2,4-bis (o-3,4-dimethylbenzylidene) sorbitol, and 1,3: 2,4-bis (o-2,4-). Dimethylbenzylidene) sorbitol, 1,3: 2,4-bis (o-4-ethylbenzylidene) sorbitol, 1,3: 2,4-bis (o-4-chlorobenzylidene) sorbitol, 1,3: 2,4 -Givenzylidene sorbitol and the like can be mentioned. Specific examples thereof include "Gelall MD" and "Gelall MD-R" (trade name) manufactured by Shin Nihon Rika Co., Ltd.
Examples of the rosin acid partial metal salt include "Pine Crystal KM1600", "Pine Crystal KM1500" and "Pine Crystal KM1300" (trade name) manufactured by Arakawa Chemical Industry Co., Ltd.

Inorganic fine particles include talc, clay, mica, asbestos, glass fiber, glass flakes, glass beads, calcium silicate, montmorillonite, bentonite, graphite, aluminum powder, alumina, silica, diatomaceous soil, titanium oxide, magnesium oxide, pebbles. Examples thereof include powder, light stone balloon, aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, dolomite, calcium sulfate, potassium titanate, barium sulfate, calcium sulfite, molybdenum sulfide and the like.
Examples of the amide compound include adipic acid dianilide and sperin acid dianilide.
Among the above nucleating agents, it is preferable to use an organic phosphate metal salt (phosphate ester metal salt) represented by the following general formula from the viewpoint of high effect of increasing the crystallization rate.
Specific examples of the organophosphate metal salt include "Adecastab NA-11", "Adecastab NA-21", "Adecastab NA-71", "Adecastab M701" and "Adecastab M801" (all manufactured by Asahi Denka Co., Ltd.). Can be mentioned.

The content of the nucleating agent is, for example, 500 ppm or more, preferably 800 ppm or more, more preferably 1250 ppm or more, and particularly preferably 1400 ppm or more. The content of the nucleating agent is preferably 10000 ppm or less, more preferably 5000 ppm or less, and further preferably 3000 ppm or less. By containing the nucleating agent, the edge cutting property of the surface layer 11, that is, the easiness of breaking at the time of opening is improved. As a non-limiting example, when the surface layer 11 is broken when the container is opened, the thickness of the surface layer 11 is preferably 5 μm or more and 40 μm or less, and more preferably 10 μm or more and 30 μm or less.

In addition, in the present embodiment, the arithmetic average roughness Ra of the surface of the surface layer 11 opposite to the surface lower layer 12 is 0.5 μm or more. As a result, the surface of the container after molding is given an appropriate roughness, and the peelability when the containers are overlapped with each other can be improved. Here, the arithmetic mean roughness Ra is defined in JIS B0601. The arithmetic average roughness Ra is preferably 0.6 μm or more, more preferably 0.7 μm or more, still more preferably 0.8 μm or more, and particularly preferably 1.0 μm or more. The upper limit of the arithmetic mean roughness Ra is not particularly limited, but is usually 3.0 μm or less.

In order to realize the arithmetic mean roughness Ra as described above, for example, the first resin composition forming the surface layer 11 may contain polyethylene. In this case, the first resin composition may contain polypropylene in an amount of 80% by mass or more and 99% by mass or less, and polyethylene may be contained in an amount of 1% by mass or more and 20% by mass or less. The melting point of polyethylene contained in the first resin composition is, for example, 115 ° C. or higher, preferably 120 ° C. or higher, and more preferably 125 ° C. or higher. The melting point of polyethylene contained in the first resin composition is, for example, 135 ° C. or lower, preferably 140 ° C. or lower. When a plurality of types of polyethylene are contained, any one type of polyethylene may be in this range. By setting the melting point of polyethylene contained in the first resin composition within this range, the arithmetic average roughness Ra as described above can be realized.

In the present invention, the melting point of polyethylene is set to a temperature range of 50 ° C. to 220 ° C. and a heating rate of 10 ° C./min using a differential scanning calorimetry device (DSC) (“Diamond DSC” manufactured by PerkinElmer Japan Co., Ltd.). The melting point is the temperature at the position where the heat absorption peak is at the top.

Further, in order to realize the arithmetic mean roughness Ra as described above, the density of polyethylene contained in the first resin composition forming the surface layer 11 is, for example, 900 kg / m ³ or more, which is preferable. Is 925 kg / m ³ or more, more preferably 945 kg / m ³ or more. The density of polyethylene contained in the first resin composition forming the surface layer 11 is, for example, 990 kg / m ³ or less, preferably 970 kg / m ³ or less, and more preferably 966 kg / m ³ or less. ..

The lower surface layer 12 is adjacent to the surface layer 11 and is formed of a resin composition containing polypropylene and polyethylene. When the main component of the surface layer 11 is polypropylene, the surface layer 12 contains polypropylene and polyethylene, so that the surface layer 11 and the surface layer 12 can be easily separated from each other. For example, the resin composition forming the surface lower layer 12 (hereinafter, also referred to as a second resin composition) may contain polypropylene in an amount of 15% by mass or more and 58% by mass or less.

The second resin composition may contain at least two types of polyethylene having different melting points from each other. The melting point of the first type of polyethylene contained in the second resin composition is, for example, 115 ° C. or higher, preferably 120 ° C. or higher, and more preferably 125 ° C. or higher. The melting point of polyethylene contained in the first type of second resin composition is, for example, 140 ° C. or lower, preferably 135 ° C. or lower. The melting point of the second type of polyethylene contained in the second resin composition is, for example, 80 ° C. or higher, preferably 90 ° C. or higher, and more preferably 100 ° C. or higher. The melting point of polyethylene contained in the second resin composition of the second category is, for example, 130 ° C. or lower, preferably 120 ° C. or lower, and more preferably 115 ° C. or lower. Depending on the polypropylene content and the polyethylene type and melting point settings, an appropriate interlayer bonding strength between the surface layer 11 and the surface layer 12 can be obtained, facilitating the peeling of the surface layer 11 and cutting the edges of the surface layer 11. The sex can be improved. The lower surface layer 15 is located on the side opposite to the surface layer 11 and the lower surface layer 12 with the base material layers 13 and 14 interposed therebetween, and is formed of the same resin composition as the lower surface layer 12.

Further, the density of the second resin composition is, for example, 850 kg / m ³ or more, preferably 880 kg / m ³ or more, more preferably 900 kg / m ³ or more, and further preferably 915 kg / m ³ or more. .. The density of the second resin composition is, for example, 970 kg / m ³ or less, preferably 950 kg / m ³ or less, and more preferably 932 kg / m ³ or less. The density can be measured by, for example, an underwater substitution method.

Further, the second resin composition may contain at least two kinds of polyethylene having different densities from each other. The density of the first type of polyethylene contained in the second resin composition is, for example, 900 kg / m ³ or more, preferably 925 kg / m ³ or more, and more preferably 945 kg / m ³ or more. The density of the first type of polyethylene contained in the second resin composition is, for example, 990 kg / m ³ or less, preferably 970 kg / m ³ or less, and more preferably 966 kg / m ³ or less. .. The density of the second type of polyethylene contained in the second resin composition is, for example, 880 kg / m ³ or more, preferably 903 kg / m ³ or more, and more preferably 910 kg / m ³ or more. The density of the second type of polyethylene contained in the second resin composition is, for example, 950 kg / m ³ or less, preferably 945 kg / m ³ or less, and more preferably 930 kg / m ³ or less. ..

In the above example, the content of polyethylene having a relatively high density contained in the second resin composition is preferably 20% by mass or more, more preferably 25% by mass or more, still more preferably 30% by mass or more. Further, 85% by mass or less is preferable, 80% by mass or less is more preferable, and 75% by mass or less is further preferable. Further, the content of polyethylene having a relatively low density when contained in the second resin composition is preferably 1% by mass or more, more preferably 2% by mass or more, still more preferably 3% by mass or more. Further, 45% by mass or less is preferable, 40% by mass or less is more preferable, and 35% by mass or less is further preferable.

By setting the polypropylene content and the polyethylene type density and content, an appropriate interlayer bonding strength can be obtained between the surface layer 11 and the surface layer 12, and the surface layer 11 can be easily peeled off from the surface. The edge breakability of the layer 11 can be improved.

By setting the melting point and density of at least two types of polyethylene contained in the second resin composition within the above ranges, a more appropriate interlayer bonding strength can be obtained between the surface layer 11 and the surface layer 12. Therefore, the edge cutting property of the surface layer 11 can be better improved while facilitating the peeling of the surface layer 11.

The base material layers 13 and 14 are laminated on the side opposite to the surface layer 11 with respect to the lower surface layer 12, and are formed of a resin containing at least one of the group consisting of, for example, an olefin resin, a polystyrene resin, and a polyester resin. Will be done. Examples of the olefin resin include polypropylene and polyethylene. Examples of the polyester resin include polyethylene terephthalate (PET). Inorganic fillers such as talc may be added to the base material layers 13 and 14 in order to improve the rigidity. An oxygen barrier layer containing an ethylene vinyl alcohol resin such as an ethylene-vinyl alcohol copolymer (EVOH) may be added between the substrate layers 13 and 14.

In the laminated body 10 described above, the layer structure other than the surface layer 11 and the surface layer 12 is arbitrary, and an additional layer may be included depending on the required rigidity and barrier property, for example. Either layer may be omitted.

FIG. 2 is a cross-sectional view showing an example of a container in which the laminate shown in FIG. 1 is molded. The container 100 shown in FIG. 2 includes a container body formed by molding the laminated body 10 and a lid body 20 joined to the container body. In the illustrated example, the container body is formed into a shape including the bottom surface portion 101, the side surface portion 102, and the flange portion 103, and the lid 20 is formed on the flange portion 103 in the joint region 105, for example, by heat sealing or the like on the container body. It is joined. In this example, the container body is molded so that the surface layer 11 of the laminated body 10 is on the inside. As a result, in the laminated body 10 forming the container body, the surface layer 11 is on the storage space SP side, and in the joining region 105, the lid 20 and the surface layer 11 of the laminated body 10 are joined.

When the containers 100 as described above are stacked after molding, the surface of the surface layer 11 is given an appropriate roughness as described above, so that the stacked containers can be easily peeled off from each other. If the surface of the surface layer 11 is excessively smooth, the air permeability between the containers is low and the adsorption force is large, which may make it difficult to peel off.

Further, as described above, since the main component of the surface layer 11 of the laminate 10 is polypropylene and the surface layer 12 contains polypropylene and polyethylene, the surface layer 11 and the surface layer 12 are easily peeled off. Utilizing this, in the container 100, the interlayer bonding strength between the surface layer 11 and the surface layer 12 of the laminate 10 constituting the container body is set between the lid 20 and the surface layer 11 in the bonding region 105. It can be weaker than the bond strength and the interlayer bond strength between the surface layer 12 and the substrate layer 13. As a result, when the user grips and peels off the end portion of the lid 20, the surface layer 11 is peeled off together with the lid 20 in the joint region 105, and the layer between the surface layer 11 and the surface layer 12 is interposed. Peel off. When the lid 20 and the surface layer 11 are peeled off to the inner edge of the joint region 105, the surface layer 11 breaks (edge breakage), and thereafter only the lid 20 is peeled off from the container body.

(Second embodiment)
Next, a second embodiment of the present invention will be described. In the present embodiment, in the laminate 10 configured in the same manner as in the first embodiment, the resin composition (second resin composition) forming the surface lower layer 12 is polypropylene and one or more types of polyethylene. And an elastomer. Since the configuration of the present embodiment is the same as that of the first embodiment described above with respect to other points, a duplicate detailed description will be omitted.

In the second embodiment, the melting point of polyethylene contained in the second resin composition is, for example, 115 ° C. or higher, preferably 120 ° C. or higher, and more preferably 125 ° C. or higher. The melting point of polyethylene contained in the second resin composition is, for example, 140 ° C. or lower, preferably 135 ° C. or lower. The elastomer contained in the second resin composition is not particularly limited, but is preferably an ethylene-α-olefin copolymer. The melt flow rate (MFR) of the elastomer is preferably 0.5 g / 10 minutes or more, and preferably 5.0 g / 10 minutes or less. The MFR of the elastomer is more preferably 0.8 g / 10 minutes or more, and further preferably 1.0 g / 10 minutes or more. The MFR of the elastomer is more preferably 4 g / 10 minutes or less, further preferably 3.5 g / 10 minutes or less, and particularly preferably 2 g / 10 minutes or less.

Appropriate layers between the surface layer 11 and the surface layer 12 by containing the content of polyethylene and polypropylene in the second resin composition forming the surface layer 12, the melting point of polyethylene, and a predetermined amount of elastomer. Bonding strength can be obtained, the edge cutting property of the surface layer 11 can be improved while facilitating the peeling of the surface layer 11, and the appearance can be further improved. The lower surface layer 15 is also formed of the same second resin composition as the lower surface layer 12.

Further, in the second embodiment, the density of the second resin composition is, for example, 850 kg / m ³ or more, preferably 880 kg / m ³ or more, more preferably 900 kg / m ³ or more, and further. It is preferably 915 kg / m ³ or more. The density of the second resin composition is, for example, 970 kg / m ³ or less, preferably 950 kg / m ³ or less, and more preferably 932 kg / m ³ or less. The density can be measured by, for example, an underwater substitution method.

Furthermore, in the second embodiment, the density of polyethylene contained in the second resin composition is, for example, 900 kg / m ³ or more, preferably 925 kg / m ³ or more, and more preferably 945 kg / m ³ or more. That is all. The density of polyethylene contained in the second resin composition is, for example, 990 kg / m ³ or less, preferably 970 kg / m ³ or less, and more preferably 966 kg / m ³ or less.

In the second embodiment, the content of the elastomer in the second resin composition is preferably 16% by mass or less, more preferably 14% by mass or less, and further preferably 10% by mass or less. It is more preferably 7% by mass or less, and particularly preferably 5% by mass or less. The lower limit value is preferably 0.5% by mass or more, more preferably 1% by mass or more, and further preferably 2% by mass or more.

Next, examples of the present invention will be described. In Table 1, the content in the resin composition forming the surface layer and the surface layer in Examples and Reference Examples is shown in mass%, respectively. The various parameters of HPP and HDPE in the surface layer and HPP, HDPE and LDPE in the subsurface layer are as follows. As the nucleating agent, the trade name ADEKA STAB M701 (manufactured by ADEKA Corporation, 5% by weight masterbatch (MB)) was used. As the elastomer, a trade name: Toughmer DF710 (manufactured by Mitsui Chemicals, Inc.), which is an ethylene-α-olefin copolymer having an MFR of 1.2 g / 10 min, was used. The laminated body is formed by laminating the surface layer, the subsurface layer, the base material layer, the adhesive layer, the oxygen barrier layer, the adhesive layer, the base material layer and the subsurface layer in this order, and the thickness of the entire laminated body is 0. It is .3 mm.

Surface layer HPP (melt flow rate: 16 g / 10 minutes, density: 900 kg / m ³ , tensile modulus: 1,600 MPa)
HDPE (melt flow rate: 0.35 g / 10 minutes, melting point: 130 ° C., density: 956 kg / m ³ )
Under-surface HPP (melt flow rate: 0.5 g / 10 minutes, density 890 kg / m ³ to 920 kg / m ³ , isotactic pendad fraction: 93 mol%)
HDPE (melt flow rate: 0.5 g / 10 minutes, melting point: 133 ° C., density: 956 kg / m ³ )
LDPE (melt flow rate: 0.35 g / 10 minutes, melting point: 109 ° C., density: 920 kg / m ³ in Examples 1 to 8 and Example 12)

Arithmetic average roughness (Ra value) measurement Using "Handy Surf E-35B" manufactured by Tokyo Precision Co., Ltd., in accordance with JIS B0601-1994, under the following measurement conditions, what is the surface layer of the surface layer? The arithmetic average roughness (Ra value) of the opposite surface was measured.
<Measurement conditions>
・ Measurement distance: 4 mm
・ Cutoff: 0.8mm
・ Needle: Tip diameter 5 μm, tip angle 90 ° cone, material diamond ・ Measuring force: 4 mN or less

The sealing strength shown in Table 1 above is such that a lid made of a film containing random polypropylene as a main component is sealed on a container body formed of a laminated body with a sealing time of 1.2 seconds, a sealing pressure of 0.24 MPa, and a seal. For those joined at a temperature of 200 ° C., the seal strength (kgf) per width of 15 mm was measured at a tensile speed of 300 mm / min using a "digital force gauge" manufactured by Imada. At this time, since the surface layer and the subsurface layer are delaminated in the container body, the measured seal strength indicates the interlayer bonding strength between the surface layer and the subsurface layer. The edge sharpness and the feeling of opening were qualitatively evaluated by a sensory test. Specifically, for the container to which the lid is joined as described above, the edge breakability and opening feeling of the surface layer when the lid is peeled off are evaluated on a scale of 5 from A (very good) to E (bad). bottom. In this evaluation, A to D are acceptable ranges.

In the embodiment, the surface layer is formed of a resin composition containing polypropylene as a main component, and the lower surface layer is formed of a resin composition containing polypropylene and polyethylene. Specifically, in Examples 1 to 4 and Example 6, the resin composition of the surface layer contains 90% by mass of polypropylene (HPP), 7% by mass of polyethylene (HDPE), and further, a nucleating agent. Is contained in an amount of 3% by mass. In Examples 5, 7 and 8, the resin composition of the surface layer contains 95% by mass of polypropylene (HPP), 5% by mass of polyethylene (HDPE), and does not contain a nucleating agent. Also in Examples 9 to 13, the resin composition of the surface layer contains 95% by mass of polypropylene (HPP), 5% by mass of polyethylene (HDPE), and does not contain a nucleating agent.

On the other hand, in Examples 1 to 5, the resin composition of the lower surface layer contains polypropylene (HPP) in an amount of 30% by mass to 45% by mass, and two types of polyethylene having different densities and melting points, specifically HDPE and LDPE. Is contained in the proportion as shown in the table. As a result, the density of the lower surface layer in Examples 1 to 5 becomes 920 kg / m ³ to 930 kg / m ³ . On the other hand, in Examples 6 to 8, the lower surface layer is formed of a resin composition containing HPP and HDPE but not LDPE. As a result, the density of the lower surface layer in Examples 6 to 8 becomes 933 kg / m ³ to 940 kg / m ³ . In Examples 9 to 11 and 13, the lower surface layer is formed of a resin composition containing HPP and HDPE but not LDPE, and an elastomer is further added. The content of the elastomer in the resin composition forming the lower surface layer is 3% by mass in Examples 9 to 11 and 15% by mass in Example 13. In Example 12, the resin composition under the surface contains 30% by mass of polypropylene (HPP), and two types of polyethylene having different densities and melting points from each other, specifically HDPE and LDPE, are contained in different proportions from Example 1. Contains in. Comparative Example 1 is an example in which the surface layer is formed of 100% HPP and the lower surface layer is formed of a resin composition containing HPP and HDPE but not LDPE.

First, the Ra value of the surface layer was 1.2 μm in each of Examples 1 to 8, which satisfied the condition of Ra ≧ 0.5 μm, which is the range exemplified in the above description. In the above embodiment, it was shown that the main component of the surface layer was HPP to improve the appearance after heating, and the peelability when the molded containers were overlapped with each other was also improved. There is. In Examples 9 to 13, the Ra value is 0.8 μm or 0.9 μm, which also satisfies the condition of Ra ≧ 0.5 μm. In Comparative Example 1 in which the surface layer was formed of 100% HPP, the Ra value was 0.4 μm, which did not satisfy the condition of Ra ≧ 0.5 μm, which is the range exemplified in the above description.

Next, regarding the evaluation of the seal strength and the edge breakability between the surface layer and the subsurface layer, the seal strength was 1.5 kgf or less in each of Examples 1 to 5, showing very good values, and Example 6 In Example 8, the value was 4.0 kgf or less, showing a good value, and the edge cutting property was A to C, so that good opening property was obtained. Also in Examples 9 to 12, the seal strength was 1.5 kgf or less, and the edge breakability was A or B, so that good openability was obtained. In Example 13, the seal strength was relatively high at 5.0 kgf, but the edge breakability was A, and the openability was good. On the other hand, in Comparative Example 1, the sealing strength exceeded 6.0 kgf and the edge cutting property was D, so that the opening property was relatively low although it was within the allowable range. The feeling of opening was A or B in Examples 9 to 12, and the best results were obtained. The opening feelings of Examples 1 to 8 and Example 13 were C or D, but improvement was seen as compared with E of the opening feeling of Comparative Example 1, and the evaluation was within the permissible range.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person skilled in the art to which the present invention belongs can come up with various modifications or modifications within the scope of the technical ideas described in the claims. Naturally, it is understood that it belongs to the technical scope of the present invention.

10 ... Laminated body, 11 ... Surface layer, 12 ... Subsurface layer, 13 ... Base layer, 14 ... Base layer, 15 ... Subsurface layer, 20 ... Lid, 100 ... Container, 101 ... Bottom, 102 ... Side , 103 ... Flange, SP ... Storage space.

Claims

A surface layer formed of a first resin composition containing polypropylene and polyethylene,
Containing at least a subsurface layer adjacent to the surface layer and formed of a second resin composition containing polypropylene and polyethylene.
A laminate having an arithmetic average roughness Ra of the surface opposite to the surface layer of the surface layer of the surface layer of 0.5 μm or more.
The laminate according to claim 1, wherein the first resin composition contains polypropylene in an amount of 80% by mass or more and 99% by mass or less, and polyethylene in an amount of 1% by mass or more and 20% by mass or less.
The laminate according to claim 1 or 2, wherein the polyethylene contained in the first resin composition has a melting point of 115 ° C. or higher and 140 ° C. or lower.
The laminate according to any one of claims 1 to 3, wherein the density of polyethylene contained in the first resin composition is 930 kg / m 3 or more.
The laminate according to any one of claims 1 to 4, wherein the polypropylene contained in the first resin composition is homopolypropylene.
The laminate according to any one of claims 1 to 5, wherein the first resin composition further contains a nucleating agent.
The laminate according to any one of claims 1 to 6, wherein the surface layer has a thickness of 5 μm or more and 40 μm or less.
The laminate according to any one of claims 1 to 7, wherein the second resin composition contains polypropylene in an amount of 15% by mass or more and 58% by mass or less.
The laminate according to any one of claims 1 to 8, wherein the second resin composition contains at least two types of polyethylene having different melting points from each other.
The laminate according to any one of claims 1 to 9, wherein the second resin composition contains at least two types of polyethylene having different densities from each other.
The laminate according to any one of claims 1 to 10, wherein the density of the second resin composition is 900 kg / m 3 or more and 970 kg / m 3 or less.
Further, a first and second base material layer laminated on the side opposite to the surface layer with respect to the lower surface layer, and an oxygen barrier layer laminated between the first and second base material layers. The laminate according to any one of claims 1 to 11, which includes.
The laminate according to claim 12, wherein the oxygen barrier layer contains an ethylene vinyl alcohol resin.
The laminate according to any one of claims 1 to 13, wherein the thickness is 0.2 mm or more and 1.5 mm or less.
A container in which the laminate according to any one of claims 1 to 14 is formed so that the surface layer is on the inside.
The laminate according to any one of claims 1 to 14, wherein the second resin composition contains an elastomer.
The laminate according to claim 16, wherein the content of the elastomer in the second resin composition is 0.5% by mass or more and 16% by mass or less.
The laminate according to claim 16 or 17, wherein the melt flow rate of the elastomer contained in the second resin composition is 0.5 g / 10 minutes or more and 5 g / 10 minutes or less.
The laminate according to any one of claims 16 to 18, wherein the elastomer contained in the second resin composition contains an ethylene-α-olefin copolymer.
A container in which the laminate according to any one of claims 16 to 19 is formed so that the surface layer is on the inside.