JP2022126192A - Oil resistant sheet and container - Google Patents

Abstract

An object of the present invention is to provide an oil-resistant sheet having excellent oil resistance.
(A) a styrenic resin containing at least one of polystyrene (GPPS) and high impact polystyrene (HIPS); (B) polyethylene; and (C) thermoplastic containing at least one of an SBS polymer and an SEBS polymer. An oil-resistant sheet made of an oil-resistant resin composition containing an elastomer.
[Selection figure] None

Description

The present disclosure relates to an oil-resistant sheet with excellent oil resistance and a container obtained from the oil-resistant sheet.

Good oil resistance is required for food containers that are used in contact with foods containing oil components such as delicatessens and confectionery, and containers for mechanical parts that come into contact with lubricating oils.
Patent Document 1 discloses a biopolyethylene (B) containing 50 to 95% by mass of a styrene resin (A) and 5 to 50% by mass of plant-derived ethylene having a biobased degree of 80 to 100% measured according to ASTM D6866. An invention of a biaxially oriented sheet (a styrene sheet for thermoforming) made of a resin composition containing and is described (claim).
It is described that the biaxially oriented sheet (styrenic sheet for thermoforming) has good oil resistance and impact resistance and can be used for food packaging (Paragraph No. 0067).

Patent Document 2 discloses a resin composition containing a polystyrene-based resin as a base resin and a polyethylene-based resin, the resin composition containing a compatibilizer, and the polystyrene-based resin being high-impact polystyrene (HIPS ) and general-purpose polystyrene (GPPS), and a sheet obtained therefrom (Claims).
It is described that the polystyrene-based resin composition has good sheet moldability and good sheet rigidity (Examples).

Patent Document 3 describes 60 to 95% by mass of a styrene resin obtained by combining polystyrene and high-impact polystyrene, 1 to 30% by mass of an olefin resin, 1 to 10% by mass of a styrene thermoplastic elastomer, and an average particle size of 2 to An invention of a thermoplastic resin sheet including a mixed resin layer containing 1 to 20% by mass of 20 μm talc is described (claim).
It is described that the thermoplastic resin sheet has good moldability, water vapor barrier properties, notch foldability, and rigidity (Paragraph No. 0010).

In Patent Document 4, one or both of a polystyrene resin and a high-impact polystyrene resin is contained in an amount of 50% by mass or more and 80% or less, and one or both of a linear low-density polyethylene resin and a high-density polyethylene resin is 20% by mass or more. An invention of a polystyrene resin film characterized by containing 50% by mass or less is described (claim).
It is described that a polystyrene resin film and a laminated foam sheet having excellent water vapor barrier properties and strength are provided (Paragraph No. 0010).

Patent Document 5 discloses a thermoplastic resin sheet including a mixed resin layer containing a styrene resin and an olefin resin as resin components, wherein a styrene resin layer containing a styrene resin is laminated on the mixed resin layer, An intermediate layer is interposed between the mixed resin layer and the styrene resin layer, the intermediate layer further comprising a styrene-based resin containing polystyrene, high-impact polystyrene, and a styrene-based thermoplastic elastomer, and an olefin-based resin; (Claims) of a thermoplastic resin sheet containing 3 to 15% by mass of an olefin resin.
The thermoplastic resin sheet can be used for various packaging applications such as food containers, beverage containers, and industrial containers. It is described that it can be suitably used for containers (Paragraph No. 0062).

JP 2020-196873 A JP 2020-193274 A Japanese Patent No. 6621292 JP 2013-204014 A Japanese Patent No. 6460989

An object of the present disclosure is to provide an oil-resistant sheet having excellent oil resistance and a container obtained from the oil-resistant sheet.

The present disclosure provides (A) a styrenic resin comprising at least one of polystyrene (GPPS) and high impact polystyrene (HIPS);
Provided are an oil-resistant sheet made of an oil-resistant resin composition containing (B) polyethylene and (C) a thermoplastic elastomer containing at least one of an SBS polymer and an SEBS polymer, and a container obtained from the oil-resistant sheet.

The oil-resistant sheet of the present disclosure has excellent oil resistance.

FIG. 5 is a plan view for explaining an oil resistance test when the sheet is in a flat state; FIG. 4 is a side view for explaining an oil resistance test when the sheet is in a folded state;

<Oil-resistant resin composition>
The styrenic resin of component (A) contains at least one of polystyrene (GPPS) and high-impact polystyrene (HIPS).
When polystyrene (GPPS) and high-impact polystyrene (HIPS) are used in combination, the content in the total amount is preferably 50 to 90% by mass of polystyrene (GPPS) and 10 to 50% by mass of high-impact polystyrene (HIPS), Polystyrene (GPPS) 60 to 80% by mass and high impact polystyrene (HIPS) 20 to 40% by mass are more preferable.

(B) Component polyethylene can be HDPE (high density polyethylene), LDPE (low density polyethylene), LLDPE (linear low density polyethylene), or the like.
The (B) component polyethylene may be petroleum-derived, but is preferably polyethylene containing plant-derived ethylene from the viewpoint of environmental problems.

The thermoplastic elastomer of component (C) is a component that acts as a compatibilizer for other ingredients, and includes SBS polymer (styrene-butadiene-styrene block polymer) and SEBS polymer (hydrogenated styrene-ethylene-butylene - styrene block polymer), or both.
Other thermoplastic elastomers include styrene-isoprene-styrene block polymer (SIS), hydrogenated styrene-ethylene-propylene-styrene block polymer (SEPS), ethylene-α-olefin polymer, ethylene-α-olefin-polyene polymer. At least one selected from coalescence, silicone rubber, acrylic rubber, and butadiene-(meth)acrylic acid ester polymer can also be contained.
When an SBS copolymer and an SEBS copolymer are used together as the thermoplastic elastomer of component (C), the content in the total amount is 50 to 80% by mass for the SBS copolymer and 20 to 50% by mass for the SEBS copolymer. is preferred, and 55 to 70% by weight of SBS copolymer and 30 to 45% by weight of SEBS copolymer are more preferred.

The content ratio of each component in the total amount of components (A) to (C) in the oil-resistant resin composition is
Preferably, component (A) is 35 to 85% by mass, component (B) is 10 to 40% by mass, and component (C) is 5 to 20% by mass.
More preferably, component (A) is 40 to 80% by mass, component (B) is 15 to 40% by mass, and component (C) is 5 to 15% by mass.
More preferably, component (A) is 50 to 80% by mass, component (B) is 15 to 35% by mass, and component (C) is 5 to 15% by mass.

The oil-resistant resin composition contains stabilizers (antioxidants such as hindered phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants, ultraviolet absorbers, etc.) within a range that does not impair the effects of the invention. light stabilizers, heat stabilizers, etc.), fluidity improvers, plasticizers, softeners, release agents, flame retardants, antistatic agents, conductive agents, antifogging agents, colorants, fillers (silica, talc) , granular fillers such as metal fillers, fibrous fillers such as glass fibers, carbon fibers, metal fibers, etc.), crystal growth agents, dispersants, foaming agents, antifoaming agents, antibacterial agents, etc. can.

<Oil-resistant sheet and container>
The oil-resistant sheet of the present disclosure is made of the oil-resistant resin composition described above.
The thickness and size of the oil-resistant sheet can be selected according to the application, and for example, the thickness can be in the range of 0.1 to 0.8 mm.
The oil-resistant sheet can be produced by applying known methods such as extrusion molding and press molding.

The oil-resistant sheet of the present disclosure may be a non-stretched sheet or a stretched sheet, but even a non-stretched sheet has excellent oil resistance. Therefore, unlike the invention of Patent Document 1, it is not necessary to perform a stretching treatment for imparting oil resistance, but in order to adjust the thickness according to the application, uniaxial stretching or biaxial stretching can be performed.
The oil-resistant sheet of the present disclosure may be a single-layer sheet or a laminated sheet, and even a single-layer sheet has excellent oil resistance. Therefore, it is not necessary to form a laminated sheet consisting of a substrate layer and a coating layer in order to impart oil resistance.
The oil-resistant sheet of the present disclosure can be obtained with excellent oil resistance in both the MD and TD directions by adjusting the components contained in the oil-resistant resin composition.
The oil-resistant sheet of the present disclosure is more preferably an unstretched single-layer sheet.

The container of the present disclosure is manufactured from the oil-resistant sheet described above, and the shape, thickness, size, etc. can be selected according to the application.
The container of the present disclosure uses the above oil-resistant sheet and is subjected to pressure forming (extrusion pressure forming, hot plate pressure forming, vacuum pressure forming, etc.), free blow forming, vacuum forming, bending, matched mold forming, and hot plate forming. It can be manufactured by applying conventional thermoforming such as.
The container of the present disclosure is a food container such as a side dish container, a lunch box container, a container for confectionery containing oil components such as chocolate, cookies, biscuits, etc., or a part thereof, and an insole sheet to be laid inside the food container (for example, the bottom of the food container). In addition to being used as a cover material for covering food in food containers, it can also be used in a wide range of fields such as OA equipment and its parts, electronic equipment and its parts, various machine parts, and miscellaneous goods.

Each aspect disclosed in this specification may be combined with any other feature disclosed in this specification.
Each configuration and combination thereof in each embodiment is an example, and addition, omission, replacement, and other changes of configuration are possible as appropriate without departing from the gist of the disclosure of the present invention. This disclosure is not limited by the embodiments, but only by the claims.

(A) Component GPPS: trade name Toyo Styrol GP G200C (Toyo Styrene Co., Ltd.)
HIPS: trade name Toyo Styrol HI E640 (Toyo Styrene Co., Ltd.)
(B) Component LLDPE (derived from petroleum): Neozex 2512F (Prime Polymer Co., Ltd.)
LLDPE (derived from plants): Green polyethylene SLH118 (Braskem SA)
(C) component SBS polymer: styrene-based thermoplastic elastomer; trade name Tufprene 126S (Asahi Kasei Co., Ltd.)
SEBS polymer: Hydrogenated styrene thermoplastic elastomer; trade name Tuftec H1043 (Asahi Kasei Co., Ltd.)

Examples 1-5, Comparative Examples 1-2
After dry-blending each component shown in Table 1, the composition was extruded under the following conditions to produce a sheet.
(Extrusion conditions)
Extruder: General-purpose horizontal extruder PG-65-32 type (Plagiken Co., Ltd.)
Cylinder temperature: 210°C
Roll temperature: 65°C
Sheet thickness: 0.4mm
Seat width: 700mm
The sheet thus obtained was cut out to have dimensions of 150 mm long and 10 mm wide, and the longitudinal direction was MD and TD. Table 1 shows the results.

<Oil resistance test>
(1) Oil resistance test 1 (test sheet is flat)
As shown in FIG. 1, a test sheet 1 was placed on a flat table 20, and absorbent cotton 2 (10 mm square) impregnated with MCT oil (medium chain fatty acid) was placed in the middle position in the length direction. The absorbent cotton 2 used was immersed in a container containing MCT oil (medium-chain fatty acid) for 60 seconds.
When the test sheet 1 was left at room temperature (20 to 25° C.) for a predetermined time, the oil resistance was confirmed by whether or not the test sheet 1 was broken when folded with a finger. The test time was 1 minute, 3 minutes, 5-60 minutes. From 5 to 60 minutes, it was taken out every 5 minutes to check whether it was broken.

(2) Oil resistance test 2 (test sheet bent)
A jig 10 shown in FIG. 2 was used.
The jig 10 has a substrate 13 and two supporting plates 11 and 12 vertically provided from the substrate portion 13 with an interval W (W=36 mm or 24 mm). A substrate 13 is fixed on a flat platform 20 . As the jig 10, two jigs with different W values can be used, or a jig whose W can be adjusted by moving two support plates 11 and 12 can be used.
As shown in FIG. 2, the test sheet 1 was sandwiched between two supporting plates 11 and 12 and held so that the middle position in the length direction was the vertex.
Absorbent cotton 2 (10 mm square) impregnated with MCT oil (medium-chain fatty acid) was placed on the vertex position of the folded portion of the test sheet 1 in the state shown in FIG. The absorbent cotton 2 used was immersed in a container containing MCT oil (medium-chain fatty acid) for 60 seconds.
When the test sheet 1 was left at room temperature (20 to 25° C.) for a predetermined time, the oil resistance was confirmed by whether or not the test sheet 1 was broken when folded with a finger. The test time was 1 minute, 3 minutes, 5-60 minutes. From 5 to 60 minutes, it was taken out every 5 minutes to check whether it was broken.

Oil resistance (crack initiation time) was measured at test times of 1 minute, 3 minutes, and 5 to 60 minutes (tested every 5 minutes). showing.
For example, 1 indicates that it did not break after 1 minute and broke after 3 minutes, 3 indicates that it did not break after 3 minutes and broke after 5 minutes, and 5 indicates that it broke after 5 minutes. 20 indicates no breakage after 20 minutes and breakage after 25 minutes.
>60 indicates that the test sheet 1 did not change after 60 minutes from the start of the test, and <1 indicates that the test sheet 1 was torn after being left for 1 minute and folded with a finger.
From the comparison of the examples containing all of the components (A) to (C) and the comparative examples that do not contain any of the components (A) to (C), the oil resistance of the examples was confirmed to be superior.
In particular, from the comparison of Examples 1 and 2, the oil resistance in both the MD and TD directions was superior when the SBS polymer was used as the component (C).

The oil-resistant sheet obtained from the oil-resistant resin composition of the present disclosure can be used as a manufacturing material for containers (various containers for food, daily necessities, electrical/electronic equipment and parts, machinery and equipment and parts, miscellaneous goods, etc.). In addition, containers for filling liquids such as beverages, food containers (containers for side dishes, lunch boxes, confectionery containers, etc.), containers for chemicals, containers for ovens and microwave ovens, containers for pouring boiling water (containers for instant food, etc.) ), containers subjected to heat sterilization, non-heated containers, and the like. Furthermore, it can be used as an insole sheet used in food containers and a cover material for covering food.

REFERENCE SIGNS LIST 1 test sheet 2 oil-containing absorbent cotton 10 jig 11, 12 support plate 13 substrate 20 stands (stands for testing)

Claims (9)

(A) a styrenic resin containing at least one of polystyrene (GPPS) and high-impact polystyrene (HIPS);
An oil-resistant sheet made of an oil-resistant resin composition containing (B) polyethylene and (C) a thermoplastic elastomer containing at least one of an SBS polymer and an SEBS polymer. When the component (A) is polystyrene (GPPS) and high-impact polystyrene (HIPS), the content in the total amount is 50 to 90% by mass of polystyrene (GPPS) and 10% by mass of high-impact polystyrene (HIPS). An oil-resistant sheet made of the resin composition according to claim 1, wherein the resin composition has a content of up to 50% by mass. 3. The oil-resistant sheet according to claim 1, wherein the polyethylene of component (B) is polyethylene containing plant-derived ethylene. When the SBS polymer and the SEBS polymer are used in combination, the content of the component (C) in the total amount is 50 to 80% by mass for the SBS polymer and 20 to 50% by mass for the SEBS polymer. Item 4. The oil-resistant sheet according to any one of items 1 to 3. In the oil-resistant resin composition, the content of component (A) is 35 to 85% by mass, the content of component (B) is 10 to 40% by mass, and the content of component (C) is 5 to 20% by mass. The oil-resistant sheet according to any one of claims 1 to 4. The oil-resistant sheet according to any one of claims 1 to 5, wherein the oil-resistant sheet is a non-oriented sheet. The oil-resistant sheet according to any one of claims 1 to 5, wherein said oil-resistant sheet is a single-layer sheet. The oil-resistant sheet according to any one of claims 1 to 5, wherein the oil-resistant sheet is an unstretched monolayer sheet. A container comprising the oil-resistant sheet according to any one of claims 1 to 8.

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