JP2005187744A - Resin composition and laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition having excellent adhesivity to an aluminum foil, exhibiting proper heat sealability to various vessels such that obtained from an expanded polystyrene, having uniformity of peel strength and further having excellent properties of protecting contents, openability at using, hot oil resistance, etc., as a heat sealing material. <P>SOLUTION: The resin composition is composed of as a component (A) 50-80 pts.mass of an ethylene-(meth)acrylic acid-(meth)acrylate copolymer or a mixed component comprising at least one of the same copolymer; as a component (B) 5-30 pts.mass of a low density polyethylene; as a component (C) 5-20 pts.mass of a low crystallinity ethylene-α-olefin copolymer; and as a component (D) ≥1 pt.mass and <5 pts.mass of a tackifier resin (the total of the components (A)-(D) is 100 pts.mass). Wherein a unit derived from (meth)acrylic acid in the component (A), is 1-10 mass% of the composition, and a unit derived from the (meth)acrylate, is 5.5-12 mass% of the composition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a resin composition suitable as a heat seal material. More specifically, it has adhesiveness with aluminum foil, and exhibits appropriate heat sealability for various containers such as expanded polystyrene or impact polystyrene (HIPS) containers, and further protects the contents when used. The present invention relates to a resin composition suitable as a heat-sealing material for an easily-openable lid material having excellent openability and heat-resistant oil resistance.

The sealing material of the container is required to protect the contents, openability at the time of use, good appearance of the opened portion after opening, and the like. Therefore, what kind of material is used for the sealing material of the container is an important issue.
For example, the cap member cover material has a five-layer structure in which a printing paper layer is formed on the outer side of the aluminum foil container via a polyethylene protective layer, and a heat seal layer is formed on the container body side of the aluminum foil via a polyethylene layer. As an example. The container body is often made of expanded polystyrene.
The reason for providing a polyethylene layer on the container body side of the aluminum foil in the above lid material is to ensure adhesion between the aluminum foil and the heat seal material layer, to provide easy opening and to form a clean opening surface. This is because it is effective. However, industrially, since it is necessary to coat a total of three layers of two polyethylene layers and a heat seal layer on an aluminum foil, processing is complicated and expensive.

  As a sealing material, an ethylene / unsaturated carboxylic acid / (meth) acrylic acid ester copolymer or an ethylene / (meth) acrylic acid copolymer and / or an ethylene / (meth) acrylic acid ester having a melting point of less than 95 ° C. Component mixed with copolymer, low density polyethylene and / or ethylene / unsaturated ester copolymer having a melting point of 95 ° C. or higher, low crystalline ethylene / α-olefin copolymer, tackifying resin, styrene / unsaturated carboxylic acid A resin composition containing an acid copolymer and containing 5 to 25% by mass of the tackifying resin is disclosed (for example, Patent Document 1).

JP 2001-198110 A

However, the resin composition disclosed in Patent Document 1 needs to further improve the uniformity of peel strength of the sealing material.
Therefore, the present inventor has studied to find a heat seal material having excellent performance even when extrusion coating is directly performed on an aluminum foil.
As such a heat seal material, first of all, it has good adhesiveness with aluminum foil, and from the viewpoint of contents protection and easy opening, shows a proper heat seal strength with the container body, and when opened The unsealed surface had to have no resin residue. In particular, when the container body is made of a foamed material such as expanded polystyrene, if the heat seal strength is too strong, the container body will be destroyed at the time of opening, while if the seal strength is weak, there will be a sealing problem and the peel strength. Therefore, it is necessary to adjust the seal strength more strictly than when a general container is used.

Secondly, in order to increase commercial value, the heat sealing material layer itself is transparent, and when hot water is poured into a container containing men, it does not cause appearance changes such as whitening due to water vapor or oil, that is, it has excellent heat resistance oil resistance. It was hoped that.
Of course, it must be excellent in food hygiene, and it was desirable to satisfy the standards defined in Ministry of Health and Welfare Notification No. 370. Furthermore, in order to increase productivity in the extrusion coating process, what can be processed at high speed is good, and what has no tendency to adhere to a winding roll or the like is desired.

  Therefore, as a result of studies to solve these problems, the present inventor is excellent for various containers such as expanded polystyrene or HIPS containers even when the following specific resin composition is directly coated on an aluminum foil. Shows performance, that is, moderate heat sealability, content protection, openability during use, uniformity of peel strength, heat resistance, food hygiene, high-speed processability, etc., and is suitable as a heat seal material As a result, they have reached the present invention.

  That is, the present invention provides an ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer (copolymer a), or the copolymer a and ethylene / (meth) acrylic acid copolymer as component (A). 50-80 parts by mass of a mixed component with one or more of a copolymer (copolymer b) and an ethylene / (meth) acrylic acid ester copolymer (copolymer c), and low density polyethylene 5-30 as component (B) 5 parts by weight of low crystalline ethylene / α-olefin copolymer as component (C), and 1 part by weight or more and less than 5 parts by weight of tackifier resin as component (D) ((A) Thru | or the sum total of (D) component is 100 mass parts), the unit derived from (meth) acrylic acid in (A) component is 1-10 mass% in a resin composition, and originates in (meth) acrylic acid ester The unit to be used is 5 in the resin composition. An invention relates to a resin composition obtained by blending such that 12% by weight.

In the present invention,
(1) The unit derived from (meth) acrylic acid in component (A) is 3 to 8% by mass in the resin composition,
(2) The density of the low density polyethylene as component (B) is 0.91 to 0.94 g / cm ³ ;
(3) The crystallinity based on X-ray diffraction of the low crystalline ethylene / α-olefin copolymer as the component (C) is 3 to 20%.
(4) It is desirable that at least one of a slip agent and an anti-blocking agent is further blended with the above-described resin composition of the present invention.

Moreover, this invention is invention regarding the heat seal material which consists of the said resin composition.
Further, the present invention provides (1) a laminate in which the heat seal material is directly formed on an aluminum foil, (2) a lid material using the heat seal material for a heat seal layer, and (3) heat seal. The invention relates to a foamed polystyrene container or an impact-resistant polystyrene container using the heat seal material for the layer.

  The resin composition of the present invention exhibits appropriate heat sealability for various containers such as expanded polystyrene containers and impact-resistant polystyrene containers, and has a uniform peel strength, and further contains the contents as a heat seal material. It is excellent in protective properties, unsealing property at the time of use, heat resistance oil resistance, and the like, and has a very small amount of n-heptane extraction.

  The resin composition of the present invention comprises, as component (A), ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer (copolymer a), or the copolymer a and ethylene / (meth) acrylic. 50-80 parts by mass of a mixed component with one or more of an acid copolymer (copolymer b) and an ethylene / (meth) acrylic ester copolymer (copolymer c), and a low density polyethylene as the component (B) 5 to 30 parts by mass, 5 to 20 parts by mass of low crystalline ethylene / α-olefin copolymer as component (C), and 1 to 5 parts by mass of tackifier resin as component (D) ( (A) thru | or (D) the sum total of a component are 100 mass parts), the unit derived from the (meth) acrylic acid in (A) component is 1-10 mass% in a resin composition, and (meth) acrylic acid Units derived from esters in the resin composition Is formulated to be .5～12 mass%, characterized by comprising.

In the present invention, as the component (A), an ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer (copolymer a) is used alone, or the copolymer a and ethylene / (meth) are used. One or more of an acrylic acid copolymer (copolymer b) and an ethylene / (meth) acrylic acid ester copolymer (copolymer c) are used in combination.
That is, as the component (A), the copolymer a, the two components composed of the copolymer a and the copolymer b, the two components composed of the copolymer a and the copolymer c, or the copolymer a and the copolymer Three components consisting of b and copolymer c are used.
Here, (meth) acrylic acid means acrylic acid and / or methacrylic acid, and (meth) acrylic acid ester means acrylic acid ester and / or methacrylic acid ester. Examples of (meth) acrylic acid esters include esters such as methyl, ethyl, n-butyl, isobutyl, 2-ethylhexyl, and isooctyl.
The ethylene / (meth) acrylic acid / (meth) acrylic acid ester acid copolymer (copolymer a) is preferably a unit derived from (meth) acrylic acid, preferably 5 to 15% by mass, particularly preferably. It is desirable that 7 to 12% by mass of units derived from (meth) acrylic acid esters are preferably copolymerized at a ratio of 5 to 25% by mass, particularly preferably 5 to 20% by mass.
As the ethylene / (meth) acrylic acid copolymer (copolymer b), the unit derived from (meth) acrylic acid is preferably 5 to 15% by mass, particularly preferably 7 to 12% by mass, The ethylene / (meth) acrylic acid ester copolymer (copolymer c) preferably has a unit derived from (meth) acrylic acid ester in a proportion of preferably 5 to 25% by mass, particularly preferably 5 to 20% by mass. It is desirable that each be copolymerized.

In each of the copolymer (a) and the copolymer (b) as the component (A), the unit derived from (meth) acrylic acid can exhibit sufficient adhesion to the aluminum foil by using the unit having a content of 5% by mass or more. Moreover, the workability in the extrusion coating process can be improved by using the above 15% by mass or less.
In the component (A) of the present invention, the (meth) acrylic acid ester in the copolymer is an essential component, and its role is important. In each of the copolymer a and the copolymer c, by using a unit derived from (meth) acrylic acid ester of 5% by mass or more, the sealing property with respect to the expanded polystyrene container which is a great effect of the present invention is achieved. It will be enough. Moreover, by using the said 25 mass% or less thing, when hot water is poured into the container containing men, it can suppress that external appearance change (heat-resistant oil resistance defect), such as whitening, is caused by water vapor | steam or an oil component.
As the component (A), it is preferable to use a component having a melt flow rate of 1 to 150 g / 10 min, particularly 1 to 100 g / 10 min at 190 ° C. and a load of 2160 g. The copolymer of component (A) can be obtained by random copolymerizing each monomer component in a process similar to that of high-pressure polyethylene.

The low density polyethylene which is the component (B) used in the present invention preferably has a density of 0.91 to 0.94 g / cm ³ , particularly 0.91 to 0.93 g / cm ³ . These may be high-pressure polyethylene or linear low-density polyethylene, but the use of high-pressure polyethylene is more preferred. The low density polyethylene preferably has a melt flow rate at 190 ° C. under a load of 2160 g of 1 to 150 g / 10 minutes, particularly 1 to 100 g / 10 minutes.

The low crystalline ethylene / α-olefin copolymer (C) used in the present invention preferably has a crystallinity of 3 to 20%, particularly 5 to 15% based on X-ray diffraction. , Α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene and other random copolymers. The copolymer (C) is usually a copolymer with good randomness containing about 82 to 93 mol% of units derived from ethylene, and an ethylene / 1-butene copolymer is particularly preferred.
As the copolymer of the component (C), those having a melt flow rate at 190 ° C. and a load of 2160 g of 0.5 to 100 g / 10 minutes, particularly 1 to 30 g / 10 minutes are preferable.
The copolymer of component (C) can be produced using, for example, a transition metal catalyst component, for example, a combination catalyst of a vanadium compound or a zirconium compound and an organoaluminum compound catalyst component.

Examples of the tackifier resin used as the component (D) in the present invention include aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, aromatic hydrocarbon resins, polyterpene resins, rosins, styrene resins, Coumarone indene resin and the like. Examples of the aliphatic hydrocarbon resin include polymers mainly composed of diolefins having 4 to 5 carbon atoms such as butene-1, isobutylene, butadiene, 1,3-pentadiene, isoprene, and piperylene. It is done.
Examples of alicyclic hydrocarbon resins include resins obtained by polymerizing diene components in spent C4 to C5 components after cyclization and dimerization, resins obtained by polymerizing cyclic monomers such as cyclopentadiene, and aromatic carbonization. Examples include a resin obtained by hydrogenating a hydrogen resin.
Examples of the aromatic hydrocarbon resin include a resin mainly composed of a vinyl aromatic hydrocarbon having 8 to 10 carbon atoms such as vinyl toluene, indene, and α-methylstyrene.
Examples of polyterpene resins include α-pinene polymers, β-pinene polymers, dipentene polymers, terpene / phenol copolymers, α-pinene / phenol copolymers, and the like.
Examples of rosins include rosins such as gum rosin, wood rosin and tall oil, and modified products thereof. Examples of the modified products include those subjected to modification means such as hydrogenation, disproportionation, dimerization, and esterification.
The styrene hydrocarbon resin is a polymer such as styrene, vinyltoluene, α-methylstyrene, isopropenyltoluene and the like.
In the present invention, the cupmen lid is most preferably a resin in which an aromatic hydrocarbon resin is hydrogenated into the core in consideration of odorlessness, food hygiene, compatibility with other components, and the like.

  The resin composition of the present invention comprises the components (A), (B), (C) and (D) as essential components, and the blending ratio of each component is 100 parts by mass of these total amounts. When component (A) is 50 to 80 parts by mass, preferably 55 to 75 parts by mass, component (B) is 5 to 30 parts by mass, preferably 10 to 25 parts by mass, and component (C) is 5 to 20 parts. It is 7 parts by weight, preferably 7 to 17 parts by weight, and the component (D) is 1 part by weight or more and less than 5 parts by weight, preferably 2 to 4.5 parts by weight.

  Furthermore, the blending of each of the above components is considered so that the unit derived from (meth) acrylic acid in component (A) and the unit derived from (meth) acrylic acid ester are in an appropriate ratio in the total resin composition. And do it. That is, the unit derived from (meth) acrylic acid in the component (A) in the resin composition is 1 to 10% by mass, preferably 3 to 8% by mass, more preferably 3.5 to 7% by mass. The unit derived from (meth) acrylic acid ester is contained in an amount of 5.5 to 12% by mass, preferably 6 to 10% by mass.

  When the blending ratio of the component (A) is less than 50 parts by mass in 100 parts by mass of the resin composition, the adhesive strength with the aluminum foil and the heat seal strength against the foamed polystyrene or impact polystyrene container are not sufficient, and the content There is a problem in physical protection, and if it exceeds 80 parts by mass, there is a problem in processability at the time of extrusion coating and in heat resistance when hot water is poured into a container containing men.

  Further, if the unit derived from (meth) acrylic acid in the resin composition is less than 1% by mass, the adhesive strength with the aluminum foil is insufficient, and if the unit exceeds 10% by mass, the unit for the expanded polystyrene container This is not preferable because the heat seal strength becomes too small. The unit derived from the (meth) acrylic acid ester in the resin composition is effective for imparting an appropriate heat seal strength to the polystyrene container at 5.5% by mass or more, and the unit exceeds the 12% by mass range. And heat resistance decreases, and it also has an adverse effect on slipperiness.

  The component (B) plays an important role in maintaining the heat resistance oil resistance, but if the amount is too large, the adhesiveness to the aluminum foil and the heat sealability are impaired. It is necessary to adjust so that it may become 30 mass parts.

  The component (C) plays a complementary role to the component (A) and can reduce the unit derived from the (meth) acrylic acid ester based on the component (A), which is indirectly effective in improving the slipperiness. However, if the amount is 5 parts by mass or more in 100 parts by mass of the resin composition, the effect can be effectively expressed. On the other hand, if it exceeds 20 parts by mass, the extrudability becomes poor.

  The component (D) is an essential component for maintaining the sealing strength, but if it is less than 1 part by mass in 100 parts by mass of the resin composition, the sealing strength is insufficient. In this case, the uniformity of the peel strength is lost, the heat resistant oil resistance is lowered, and the n-heptane extraction amount may be increased. There is.

  Although the basic performance of the lid material can be achieved by a composition containing only the components (A), (B), (C), and (D), industrially, good workability is desired. ing. In the composition of only the above four components, blocking or roll adhesion may occur, which may hinder high-speed continuous processing. For this reason, it is desirable to add a small amount of a slip agent and / or an anti-blocking agent. Such additives include saturated or unsaturated fatty acid amides such as stearic acid amide, oleic acid amide, erucic acid amide, palmitic acid amide, behenic acid amide, oleyl palmitamide, stearyl erucamide, N, N One or more of hydrogenated castor oil, silica, etc., such as' -methylenebisstearylamide, N, N'-ethylenebiserucamide, etc. can be used. The amount of these used is, for example, in the range of 0.1 to 5 parts by mass, particularly 0.3 to 3 parts by mass per 100 parts by mass of the total amount of the components (A), (B), (C), and (D). Good.

  In view of the extrusion processability, the resin composition of the present invention as described above is preferably adjusted to a melt flow rate of 1 to 400 g / 10 min, particularly 1 to 150 g / 10 min at 190 ° C. and a load of 2160 g. .

  The resin composition of the present invention is useful as a heat seal material. In particular, it is useful as a sealing material for a laminated material including an aluminum foil layer because a good adhesion can be obtained by extrusion coating directly on the aluminum foil layer. Such extrusion coating can be performed using a single-layer molding apparatus, but low-density polyethylene and the above resin composition are extrusion coated on both sides of an aluminum foil using a tandem molding apparatus to reduce the printing paper. If bonded to the density polyethylene side, a laminated lid material having a four-layer structure can be manufactured in one step.

Such a laminated lid material can be used as a lid material for various plastic containers for food, medicine, medical supplies, etc., and has a suitable sealing strength especially for expanded polystyrene. And a heat seal layer of an expanded polystyrene container or an impact-resistant polystyrene container.
Specifically, the resin composition of the present invention is useful as an easily openable heat seal material. When used as an easy-open sealant, it is often used in the form of being laminated on a base material, but because of its good adhesiveness with aluminum foil, the use of a laminate containing aluminum foil as a seal material is especially Useful. As typical laminated material configurations, for example, the following can be exemplified, but of course, a part of them can be replaced with another material, or another material can be further laminated. That is, when the resin composition of the present invention is expressed as a sealing material, a printing protective layer / printing layer / aluminum foil / sealing material, biaxially oriented polyester / printing layer / adhesive / aluminum foil / sealing material, biaxially oriented polypropylene / Examples of the laminated material include a printed layer / adhesive / sealant, a print protective layer / print layer / paper / seal material, and a polyethylene / print layer / paper / polyethylene / aluminum foil / seal material.

  Examples and comparative examples are shown below to explain the effects of the present invention. In addition, the raw material used in the Example etc. and the physical-property evaluation method of the obtained laminated lid | cover material are as follows.

1. Raw material resin (1) Copolymer A-1
As ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer (copolymer a), ethylene unit 80% by mass, methacrylic acid unit 10% by mass, isobutyl acrylate unit 10% by mass, 190 ° C. A copolymer having a melt flow rate (MFR) at a load of 2160 g of 36 g / 10 min was used.
(2) Copolymer A-2
As ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer (copolymer a), ethylene unit 81% by mass, methacrylic acid unit 4% by mass, isobutyl acrylate unit 15% by mass, 190 ° C. A copolymer having an MFR at a load of 2160 g of 27 g / 10 min was used.
(3) Copolymer A-3
An ethylene / (meth) acrylic acid ester copolymer (copolymer c) comprising 80% by mass of ethylene units and 20% by mass of methyl acrylate units, and having an MFR of 8 g / 10 min at 190 ° C. under a load of 2160 g. A polymer was used.
(4) Copolymer A-4
An ethylene / (meth) acrylic acid copolymer (copolymer b) comprising 91% by mass of ethylene units and 9% by mass of methacrylic acid units and having an MFR of 12 g / 10 min at 190 ° C. under a load of 2160 g It was used.

(5) Low density polyethylene As the component (B), a low density polyethylene having an MFR of 4.5 g / 10 min at 190 ° C. and a load of 2160 g and a density of 0.923 g / cm ³ was used.
(6) Low crystalline ethylene / α-olefin copolymer (C) As a component, a low crystalline ethylene / α-olefin copolymer having an MFR of 3.6 g / 10 min at 190 ° C. under a load of 2160 g (Mitsui Chemical ( Co., Ltd., trade name: TAFMER A4085) was used.
(7) Tackifying resin (D) As component (D), alicyclic hydrocarbon resin having a ring-and-ball softening point of 115 ° C. (intranuclear hydrogenated resin of aromatic hydrocarbon resin) (trade name, manufactured by Arakawa Chemical Co., Ltd.) : Alcon P-115) was used as tackifying resin.
(8) Other components Fatty acid amide was used as an anti-slip agent, and silica was used as an anti-blocking agent.

2. Laminate lid material properties Lamination method and processing appropriate evaluation composition pellets were melt-extruded from a T-die with a 65 mm diameter extruder at a die outlet resin temperature of 250 ° C., and were prepared in advance (basis weight 79 g / m ² ) / low density polyethylene film (thickness: 15 μm) / aluminum foil (thickness: 9 μm) of the three-layer flexible lid material on the aluminum foil surface with a processing speed of 80 m / min and a coating thickness of 25 μm Extrusion coating was performed under the conditions to obtain a laminated lid material. Furthermore, while maintaining the extrusion conditions at the above-mentioned conditions, only the processing speed was gradually increased to perform processing, and the maximum processing speed was evaluated. Next, the aluminum foil adhesive strength, heat seal strength, and heat resistance oil resistance of the heat seal material layer of the obtained cover material were measured by the following methods.

(1) Aluminum foil adhesive strength A sample 7 days after processing was measured under conditions of a sample width of 15 mm, a peeling angle of 90 degrees, and a tensile strength of 300 mm / min.
(2) HIPS adhesiveness and uniformity during peeling Using a heat sealer, the laminated lid material was heat-sealed with a strip-shaped sample of a HIPS container for a cup ramen container, and the heat seal strength was measured. .
Sealing conditions: temperature 130 ° C., 140 ° C., 150 ° C., pressure 0.1 MPa, time 0.5 sec. Further, the uniformity during peeling was judged according to the following criteria.
○: Peeling strength is constant and peeling noise is small.
X: Peeling strength is not constant and peeling noise is large.
(3) Heat-resistant oil whitening test A cup-ramen container made of expanded polystyrene in which salad oil is applied in a circular shape with a diameter of 10 cm to the heat-seal material layer of the heat-resistant oil-resistant laminated lid, and the salad oil application part has an opening with a diameter of 15 cm. Heat seal without touching, and then peel off the container lid after it has cooled sufficiently. Pour boiling water from the opening to 5 mm below the lid of the container. The lid was put back on and left for 5 minutes. Thereafter, the lid was peeled from the container, and the appearance change of the salad oil application part of the heat seal material layer was observed. The heat resistance was evaluated in the following four stages.
A: No abnormality at all immediately after opening.
○: Slightly whitened directly after opening, but immediately disappeared.
Δ: Whitening immediately after opening, and then gradually disappears.
X: Whitening occurs immediately after opening, and does not disappear after that.

(4) Extraction amount of n-heptane Extruded with an evaluation composition at a coating thickness of 30 μm in the same manner as in the production of a laminated lid on a polyethylene terephthalate (PET) (thickness 12 μm) / low-density polyethylene (thickness 20 μm) film prepared in advance. The coating process was performed and the test base material was obtained. Using this test substrate, the n-heptane elution test specified in Ministry of Health and Welfare Notification No. 370 was performed by single-sided extraction of the evaluation composition surface, and the evaporation residue amount was measured to obtain the n-heptane extraction amount.
(5) Maximum machining speed The “maximum processing speed” described in the physical properties of the laminated lid was adopted.

(6) Comprehensive evaluation About each said measured value, the target value as a lid | cover material was set to following (a)-(e), and comprehensive evaluation was performed on the basis of these.
(A) Maximum processing speed: 200 m / min or more (b) Aluminum foil adhesion: 2.0 N / 15 mm or more (c) vs. HIPS heat seal strength: 13-30 N / 15 mm
(D) Heat-resistant oil resistance: ◎
(E) Uniformity during peeling: ○

A-1 as the ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer, A-3 as the ethylene / (meth) acrylic acid ester copolymer, ethylene / (meth) acrylic acid copolymer As a mixture of the above A-4, high pressure method low density polyethylene, low crystalline ethylene / α-olefin copolymer, tackifier resin, fatty acid amide and silica in the ratio shown in Table 1, It was melt-kneaded under a resin temperature of 150 ° C. to obtain a composition.
Using this composition, a laminated lid was prepared by the above-described method, and the physical properties were evaluated. The results are shown in Table 1.

  Except for the components and blending ratios shown in Table 1, melt-kneading was carried out in the same manner as in Example 1 to obtain the compositions shown in Table 1. From this, laminate lid materials were produced and the physical properties were evaluated. The results are shown in Table 1.

A-1 and A-2 as ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer, A-3 as ethylene / (meth) acrylic acid ester copolymer, and ethylene / (meta ) A mixture of A-4, high-pressure low-density polyethylene, low-crystalline ethylene / α-olefin copolymer, tackifier resin, fatty acid amide and silica in the proportions shown in Table 1 was used as the acrylic acid copolymer. In a shaft extruder, the mixture was melt-kneaded under a resin temperature of 150 ° C. to obtain a composition.
Using this composition, a laminated lid was prepared by the above-described method, and the physical properties were evaluated. The results are shown in Table 1.

[Comparative Example 1]
As the ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer, the A-1, the high pressure method low density polyethylene, the low crystalline ethylene / α-olefin copolymer, the tackifier resin, the fatty acid amide and the silica are used. The mixture blended at the ratio shown in Table 1 was melt kneaded under a resin temperature of 150 ° C. with a single screw extruder to obtain a composition.
Using this composition, a laminated lid was prepared by the above-described method, and the physical properties were evaluated. The results are shown in Table 1.

  The heat-sealable resin composition of the present invention is used as a heat-seal material for various containers made of a wide range of packaging materials such as thermoplastic resins, metals, glass, etc., especially for expanded polystyrene containers such as cupmen and impact-resistant polystyrene containers. It can be widely used as a heat seal material such as a lid material.

Claims (9)

  As component (A), ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer (copolymer a), or the copolymer a and ethylene / (meth) acrylic acid copolymer (copolymer) b) and 50-80 parts by mass of a mixed component with one or more of ethylene / (meth) acrylic acid ester copolymer (copolymer c), 5-30 parts by mass of low density polyethylene as component (B), (C 5) 20 parts by mass of a low crystalline ethylene / α-olefin copolymer as a component, and 1 part by mass or more and less than 5 parts by mass of a tackifier resin as a component (D) (components (A) to (D) Is 100 parts by mass), the unit derived from (meth) acrylic acid in component (A) is 1 to 10% by mass in the resin composition, and the unit derived from (meth) acrylic acid ester is the resin composition. 5.5 to 12% by mass in the product Resin composition obtained by blending such.   The resin composition according to claim 1, wherein the unit derived from (meth) acrylic acid in component (A) is 3 to 8% by mass in the resin composition. The resin composition according to claim 1 or 2, wherein the density of the low-density polyethylene as the component (B) is 0.91 to 0.94 g / cm ³ .   4. The resin composition according to claim 1, wherein the crystallinity based on X-ray diffraction of the low crystalline ethylene / α-olefin copolymer as component (C) is 3 to 20%.   The resin composition according to any one of claims 1 to 4, wherein at least one of a slip agent and an antiblocking agent is blended.   A heat seal material comprising the resin composition according to claim 1.   A laminate in which the heat seal material according to claim 6 is directly formed on an aluminum foil.   The lid | cover material which uses the heat seal material of Claim 6 for a heat seal layer.   A foamed polystyrene container or an impact-resistant polystyrene container using the heat seal material according to claim 6 for the heat seal layer.