JP2008195928A - Resin for sealant film and film comprising same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealant film being excellent in the low temperature heat-sealing property. <P>SOLUTION: The sealant film resin comprises 85 to 94 mol% of recurring units derived from ethylene and 6 to 15 mol% of recurring units induced from a vinyl compound (100 mol% in total). The vinyl compound is represented by the structural formula: CH<SB>2</SB>=CH-R wherein the substituent R is a 3-10C cyclic hydrocarbon group. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a resin for a sealant film and a film using the same.

In recent years, the demand for packaging materials using thermoplastic resin sealant films and adhesives has greatly increased as product packaging becomes highly functional or individually packaged. For example, JP2002-2002
No. 105277 describes a polypropylene film from a resin composition containing a specific propylene copolymer and a specific propylene-ethylene block copolymer. Japanese Patent Application Laid-Open No. 2003-82028 discloses a copolymer of ethylene and a vinyl compound represented by CH2 = CH-R, wherein carbon substituted with a substituent R in the skeleton of the copolymer. An adhesive comprising a copolymer having a structure in which atoms are separated by one methylene group is described.

JP 2002-105277 A JP 2003-82028 A

However, in recent years, in the packaging field of foods and the like, the speed of bag making has been increased, and materials that can cope with the speed of bag making have been demanded, and further improvement is required for the low temperature heat sealability of the film. It has been.
Under such circumstances, an object of the present invention is to provide a sealant film excellent in low temperature heat sealability.

  As a result of intensive studies, the present inventors have found that the present invention can solve the above problems, and have completed the present invention.

That is, the present invention is a resin for sealant films containing 85 to 94 mol% of repeating units derived from ethylene and 6 to 15 mol% of repeating units derived from vinyl compounds (repeating units derived from ethylene). And the vinyl compound is represented by the structural formula CH2 = CH-R, and the substituent R has 3 to 10 carbon atoms. The alicyclic hydrocarbon group is represented by the resin for sealant films.

ADVANTAGE OF THE INVENTION According to this invention, the resin for sealant films excellent in low-temperature heat-sealing property and a film consisting thereof can be obtained.

  In the present specification, the vinyl compound is represented by the structural formula CH2 = CH-R, and the substituent R represents an alicyclic hydrocarbon group having 3 to 10 carbon atoms. Here, the substituent R of the vinyl compound is an alicyclic hydrocarbon group having 3 to 10 carbon atoms, specifically, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group. , A cyclooctyl group, a norbornyl group, and the like. Preferred are a cyclohexyl group and a cycloheptyl group, and more preferred is a cyclohexyl group.

  In the resin for sealant films of the present invention, the content of repeating units derived from ethylene is 85 to 94 mol%, preferably 87 to 94 mol%. That is, the content of the repeating unit derived from the vinyl compound in the resin for a sealant film of the present invention is 6 to 15 mol%, preferably 6 to 13 mol%. When the ethylene content is less than 85 mol%, the stickiness at room temperature is so bad that it is not suitable for use as a sealant film. On the other hand, when the ethylene content is more than 94 mol%, sufficient low temperature heat sealability may not be exhibited. The resin for sealant films of the present invention can be particularly suitably used for sealant film applications by setting such a specific comonomer content.

  The resin for a sealant film of the present invention is obtained by copolymerizing ethylene and a vinyl compound, and may further copolymerize a monomer capable of addition polymerization. Examples of such monomers include cyclic olefins, vinylidene compounds, diene compounds, vinyl halides, vinyl alkylates, vinyl ethers, acrylonitriles, and the like.

  The intrinsic viscosity [η] of the resin for a sealant film of the present invention is 0.2 to 10 dl / g, preferably from the viewpoints of good fluidity and excellent film forming property and sufficient heat seal strength. It is 0.3-5 dl / g, More preferably, it is 0.4-5 dl / g.

  The resin for a sealant film of the present invention can be produced, for example, by copolymerizing ethylene and a vinyl compound in the presence of a catalyst obtained by contacting isopropylidenebis (indenyl) zirconium chloride and methylalumoxane. it can. In that case, a copolymerization composition, molecular weight, etc. can be adjusted by changing suitably polymerization conditions, such as the injection amount of ethylene or a vinyl compound, polymerization temperature, and polymerization time.

  If necessary, additives and other resins may be added to the resin for sealant films of the present invention. Examples of the additive include an antioxidant, an ultraviolet absorber, an antistatic agent, a lubricant, a nucleating agent, an antifogging agent, and an antiblocking agent. Examples of other resins include ethylene resins, butene resins, petroleum resins, and styrene resins.

  As a method for producing a film comprising the resin for a sealant film of the present invention, a method for forming a resin for a sealant film alone using a commonly used T-die method, a calendar method, or the like, or a multilayer structure with different resins The method of forming into a film as an outermost layer of at least one side is mentioned. Examples of the multilayering method include an extrusion laminating method, a thermal laminating method, and a dry laminating method that are generally used. Examples of the resin different from the sealant film resin of the present invention include polypropylene, polyethylene, and polyethylene terephthalate.

The film made of the resin for a sealant film of the present invention can be produced by stretching. Examples of the stretching method include a method of stretching uniaxially or biaxially by a roll stretching method, a tenter stretching method, a tubular stretching method, or the like Is mentioned. From the viewpoint of excellent low-temperature heat sealability and transparency of the film, a biaxial stretching method is preferred.
In the case of a single layer, the film of the present invention has a thickness of 5 to 50 μm, preferably 10 to 30 μm, from the viewpoint of excellent handling properties. In the case of a multilayer structure, the film is excellent in low temperature heat sealability. From the viewpoint, the thickness of the surface layer sealant is 0.5 to 10 μm, preferably 0.5 to 5 μm.

  The film made of the resin for a sealant film of the present invention can be used for industrial films such as protective films, food packaging films such as confectionery packaging, and the like.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The sample preparation methods and physical property measurement methods used in Examples and Comparative Examples are shown below.

(1) Intrinsic viscosity of resin (A) ([η], unit: dl / g)
The measurement was performed in 135 ° C. tetralin using an Ubbelohde viscometer.

(2) Polypropylene melt flow rate (MFR, unit: g / 10 min)
According to JIS K7210, the measurement was performed at a temperature of 230 ° C. and a load of 21.18 N.

(3) Melting point of resin for sealant film (Tm, unit: ° C)
A differential scanning calorimetry curve was measured using a differential scanning calorimeter (SSC-5200, manufactured by Seiko Denshi Kogyo Co., Ltd.) under the following conditions, and was determined from the differential scanning calorimetry curve during the second temperature increase.
<Measurement conditions>
Temperature rise (first time): The temperature was raised from 20 ° C. to 200 ° C. at 10 ° C./min, and then held at 200 ° C. for 10 minutes.
Temperature decrease: Immediately after the first temperature increase operation, the temperature was decreased from 200 ° C. to −100 ° C. at a rate of 10 ° C./min, and then held at −100 ° C. for 10 minutes.
Temperature increase (second time): Immediately after the temperature decrease operation, the temperature was increased from −100 ° C. to 200 ° C. at 10 ° C./min.
(4) Using a glass transition point differential scanning calorimeter (SSC-5200, manufactured by Seiko Denshi Kogyo Co., Ltd.) of a resin for a sealant film, measurement was performed under the following conditions, and the inflection point was obtained.
Condition adjustment: After raising the temperature from 20 ° C. to 200 ° C. at 20 ° C./min, holding at 200 ° C. for 10 minutes, and then lowering the temperature from 200 ° C. to −50 ° C. at 20 ° C./min, Retained.
It calculated | required when heating up at a speed | rate of 20 degree-C / min from -50 degreeC to 300 degreeC.

(5) Content of repeating unit derived from vinylcyclohexane in ethylene-vinylcyclohexane copolymer Content of repeating unit derived from vinylcyclohexane in ethylene-vinylcyclohexane copolymer is determined by carbon nuclear magnetic resonance method. The carbon nuclear magnetic resonance spectrum (13C-NMR) was measured under the following measurement conditions and calculated from the following formula.
<Measurement conditions>
Apparatus: ARX400 manufactured by Bruker
Measuring solvent: 4: 1 (volume ratio) mixture of orthodichlorobenzene and orthodichlorobenzene-d4 Measuring temperature: 408K
Measurement method: Powergate Decoupling method Pulse angle: 45 degrees Measurement standard: Trimethylsilane <Calculation formula>
Vinylcyclohexane unit content (mol%) = 100 × A / (B-2A)
A: Integrated integrated value of 45 ppm to 40 ppm signal B: Integrated integrated value of 35 ppm to 25 ppm signal (6) Propylene content in propylene / 1-butene copolymer Polymer Analysis Handbook (published by Kinokuniya, 1995) IR spectrum measurement described on page 619 of) was performed to determine the 1-butene content.

(7) Heat seal temperature (HST, unit: ° C)
The surfaces of the films were overlapped and heat sealed by heat-sealing by heating at a predetermined temperature (Toyo Seiki Co., Ltd.) (10 mm × 15 mm) with a load of 2 kg / cm 2 G for 2 seconds. After this sample was conditioned at 23 ° C. and 50% humidity all day and night, a seal with a peeling resistance of 300 g / 25 mm when peeled at 23 ° C., humidity 50%, peeling rate 200 mm / min, peeling angle 180 ° C. The temperature was determined and used as the heat seal temperature.

(8) Transparency (Haze, unit:%)
It measured according to JIS K7136.

[Example 1] Synthesis of ethylene / vinylcyclohexane copolymer (A-1) 38.6 kg of vinylcyclohexane and 364 kg of toluene were charged into a SUS reactor substituted with dry nitrogen, and the temperature was raised to 50 ° C in a sealed state. Warm up. Next, 0.015 MPa of hydrogen was introduced. After the introduction of hydrogen was completed, 0.6 MPa of ethylene was introduced. Next, 1.0 kg of a toluene solution of triisobutylaluminum [manufactured by Tosoh Akzo Co., Ltd., triisobutylaluminum concentration 20 wt%] was charged, followed by diethylsilyl (tetramethylcyclopentadienyl) (3-tert-butyl- 5-methyl-2-phenoxy) titanium dichloride 0.1 g dissolved in dehydrated toluene 8.7 kg and dimethylanilinium tetrakis (pentafluorophenyl) borate 3 g dissolved in dehydrated toluene 12.2 kg Polymerization was started. During the polymerization, the polymerization solution was stirred, and ethylene was supplied into the reactor so that the pressure of ethylene was maintained at 0.6 MPa. Two hours after the start of polymerization, 0.9 kg of ethanol was added to the polymerization solution. Next, a 2 wt% hydrochloric acid aqueous solution equivalent to the polymerization solution was added to the polymerization solution, and the aqueous layer and the organic layer were separated. The organic layer was collected and poured into a large amount of acetone, and a cloudy white solid was collected. The solid was washed with acetone and dried under reduced pressure. As a result, 30 kg of copolymer (A-1) was obtained. The ethylene unit content of the polymer was 88 mol%, and the vinylcyclohexane unit content was 12 mol%. Further, only one melting peak was confirmed, the melting point was 62 ° C., the glass transition point was −28 ° C., and [η] was 0.5 dl / g.

[Propylene sheet preparation]
Add pellets of polypropylene FS2016 (MFR = 2, Tm = 160 ° C.) manufactured by Sumitomo Chemical Co., Ltd. into a 110 mm × 110 mm × 0.5 mm mold, and heat press molding (preheat at 230 ° C. for 5 minutes, then take 3 minutes) The pressure was increased to 50 kgf / cm 2 and held for 2 minutes, and then cooled at 30 ° C. and 30 kgf / cm 2 for 5 minutes to obtain a 500 μm sheet.
[Creation of sheet made of copolymer (A-1)]
Add copolymer (A-1) into a 110mm x 110mm x 0.1mm mold and heat press mold (preheat at 180 ° C for 3 minutes, then pressurize to 50kgf / cm2 over 3 minutes and hold for 2 minutes. And then cooled at 30 ° C. and 30 kgf / cm 2 for 5 minutes) to prepare a 100 μm sheet.
[Create multilayer film]
The obtained propylene sheet and a sheet made of the copolymer (A-1) were superposed and hot press-molded (after preheating at 180 ° C. for 3 minutes, pressurizing to 10 kgf / cm 2 over 2 minutes and holding for 2 minutes) And cooled at 30 ° C. and 30 kgf / cm 2 for 5 minutes) to obtain a multilayer film.
[Creation of biaxially stretched film]
The obtained multilayer sheet is punched into a size of 92 mm × 92 mm, and biaxially stretched by simultaneously biaxially stretching 5 × 5 times at a stretching temperature of 150 ° C. at a rate of 5 m / min with a desktop stretching machine manufactured by Toyo Seiki Co., Ltd. It was created. Table 1 shows the physical properties of the obtained film.

[Example 2] Synthesis of ethylene / vinylcyclohexane copolymer (A-2) 176 g of vinylcyclohexane and 1495 g of toluene were charged into a SUS reactor substituted with dry nitrogen, and the temperature was raised to 53 ° C in a sealed state. . Next, 0.9 MPa of ethylene was introduced. Next, 3.0 g of a toluene solution of triisobutylaluminum [manufactured by Tosoh Akzo Co., Ltd., triisobutylaluminum concentration 20 wt%] was charged, followed by diethylsilyl (tetramethylcyclopentadienyl) (3-tert-butyl- 5-methyl-2-phenoxy) titanium dichloride 0.1 mg dissolved in dehydrated toluene 1.7 g and dimethylanilinium tetrakis (pentafluorophenyl) borate 12 mg dissolved in dehydrated toluene 13.1 g Polymerization was started. During the polymerization, the polymerization solution was stirred, and ethylene was supplied into the reactor so that the pressure of ethylene was maintained at 0.9 MPa. After 1.5 hours from the start of polymerization, 5 g of ethanol was added to the polymerization solution. Next, a 2 wt% hydrochloric acid aqueous solution equivalent to the polymerization solution was added to the polymerization solution, and the aqueous layer and the organic layer were separated. The organic layer was collected and poured into a large amount of acetone, and a cloudy white solid was collected. The solid was washed with acetone and dried under reduced pressure. As a result, 160 g of copolymer (A-2) was obtained. The polymer had an ethylene unit content of 91.2 mol% and a vinylcyclohexane unit content of 8.8 mol%. Further, only one melting peak was confirmed, the melting point was 77 ° C., the glass transition point was −23 ° C., and [η] was 0.94 dl / g.

[Example 3] Synthesis of ethylene / vinylcyclohexane copolymer (A-3) 176 g of vinylcyclohexane and 1169 g of hexane were charged into a SUS reactor substituted with dry nitrogen, and the temperature was raised to 60 ° C in a sealed state. . Next, 0.9 MPa of ethylene was introduced. Next, 4.0 g of a toluene solution of triisobutylaluminum [manufactured by Tosoh Akzo Co., Ltd., triisobutylaluminum concentration 20 wt%] was charged, and then diethylsilyl (tetramethylcyclopentadienyl) (3-tert-butyl- 5-methyl-2-phenoxy) titanium dichloride 0.12 mg dissolved in dehydrated hexane 0.8 g and dimethylanilinium tetrakis (pentafluorophenyl) borate 8 mg dissolved in dehydrated toluene 6.7 g were charged, Polymerization was started. During the polymerization, the polymerization solution was stirred, and ethylene was supplied into the reactor so that the pressure of ethylene was maintained at 0.9 MPa. 6.5 hours after the start of polymerization, 5 g of ethanol was added to the polymerization solution. Next, a 2 wt% hydrochloric acid aqueous solution equivalent to the polymerization solution was added to the polymerization solution, and the aqueous layer and the organic layer were separated. The organic layer was collected and poured into a large amount of acetone, and a cloudy white solid was collected. The solid was washed with acetone and dried under reduced pressure. As a result, 151 g of copolymer (A-3) was obtained. The polymer had an ethylene unit content of 89.7 mol% and a vinylcyclohexane unit content of 10.3 mol%. Further, only one melting peak was confirmed, the melting point was 72 ° C., the glass transition point was −25 ° C., and [η] was 0.82 dl / g.

[Comparative Example 1] Polymerization of propylene / 1-butene copolymer [synthesis of solid catalyst]
After replacing an SUS reaction vessel with an internal volume of 200 L with a stirrer with nitrogen, 80 L of hexane, 6.55 mol of tetrabutoxytitanium, 2.8 mol of diisobutyl phthalate and 98.9 mol of tetrabutoxysilane were added to obtain a homogeneous solution. did. Next, 51 L of a diisobutyl ether solution of butyl magnesium chloride having a concentration of 2.1 mol / L was gradually added dropwise over 5 hours while maintaining the temperature in the reaction vessel at 5 ° C. After completion of the dropwise addition, the mixture was further stirred at room temperature for 1 hour, then solid-liquid separation was performed at room temperature, and washing was repeated 3 times with 70 L of toluene.
Next, after extracting toluene so that the slurry concentration becomes 0.6 kg / L, a mixed solution of 8.9 mol of n-butyl ether and 274 mol of titanium tetrachloride was added, and 20.8 mol of phthalic acid chloride was further added. In addition, the reaction was carried out at 110 ° C. for 3 hours. After completion of the reaction, washing was performed twice with toluene at 95 ° C.
Next, after adjusting the slurry concentration to 0.6 kg / L, 3.13 mol of diisobutyl phthalate, 8.9 mol of n-dibutyl ether and 137 mol of titanium tetrachloride were added, and the reaction was carried out at 105 ° C. for 1 hour. After completion of the reaction, the solid and liquid were separated at the same temperature, and then washed twice with 90 L of toluene at 95 ° C.
Next, after adjusting the slurry concentration to 0.6 kg / L, 8.9 mol of n-dibutyl ether and 137 mol of titanium tetrachloride were added, and the reaction was performed at 95 ° C. for 1 hour. After completion of the reaction, solid-liquid separation was performed at the same temperature, and washing was performed 3 times with 90 L of toluene at the same temperature.
Next, after adjusting the slurry concentration to 0.6 kg / L, 8.9 mol of n-dibutyl ether and 137 mol of titanium tetrachloride were added, and the reaction was performed at 95 ° C. for 1 hour.
After completion of the reaction, solid-liquid separation was performed at the same temperature, followed by washing with 90 L of toluene three times at the same temperature, and further washing with 90 L of hexane three times, followed by drying under reduced pressure to obtain 11.0 kg of a solid catalyst component.
The solid catalyst component contains 1.89% by weight of titanium atom, 20% by weight of magnesium atom, 8.6% by weight of phthalate ester, 0.05% by weight of ethoxy group and 0.21% by weight of butoxy group. It had a good particle property.
[Preactivation of solid catalyst]
Fully dehydrated and degassed 1.5 L of n-hexane, 37.5 mmol of triethylaluminum, 3.75 mmol of t-butyl-n-propyldimethoxysilane, and the above solid catalyst in a SUS autoclave with an internal volume of 3 L and equipped with a stirrer After 15 g of propylene was added, 15 g of propylene was continuously supplied over 30 minutes while preserving the temperature in the tank at 5 to 15 ° C. and preactivation was performed, the resulting solid catalyst slurry was equipped with a 200 L internal stirrer It was transferred to a SUS autoclave, diluted with 140 L of liquid butane, and stored at a temperature of 5 ° C. or lower.
[Polymerization of propylene / 1-butene copolymer]
(First step)
In a SUS polymerization tank with an internal volume of 300 L and equipped with a stirrer, liquid propylene 35 Kg / hr, 1-butene 13 Kg / hr and hydrogen in such an amount that the gas phase concentration is maintained at 0.5 vol% are supplied, and further preliminary activity The solid polymerization catalyst component 0.6 g / hr was supplied, and slurry polymerization using liquid propylene as a medium was continued under the conditions of maintaining the polymerization temperature at 60 ° C. and the substantial amount of slurry retained in the tank at 90 L. The amount of polymer produced at this time was 2.0 kg / hr. As a result of analyzing a part of the polymer, the butene content was 7.7 mol%. The obtained slurry containing the polymer was continuously transferred to the second step polymerization tank without being deactivated.
(Second step)
In a gas phase fluidized bed reactor with an internal volume of 1 m 3 and a stirrer, the amount of polymer retained in the fluidized bed is 80 kg, the polymerization temperature is 65 ° C., the polymerization pressure is 1.15 MPa, the hydrogen concentration in the gas phase is 2.5 vol%, The solid catalyst component-containing polymer and triethylaluminum 50 mmol / hr transferred from the first-stage reactor under conditions where propylene, hydrogen and 1-butene were supplied so as to maintain the 1-butene concentration at 25 vol%, and The propylene copolymer (X-1) 22.2 kg / hr was obtained by supplying t-butyl- n-propyl dimethoxysilane 5 mmol / hr and continuing continuous polymerization. The 1-butene content of the polymer was 20.0 mol%. The weight ratio of the polymer (component A) in the first step and the polymer (component B) in the second step is 10/90 from the amount of polymer produced in each step, and the 1-butene content of the B component is It was 21.7 mol%.

[Comparative Example 2] Synthesis of ethylene / vinylcyclohexane copolymer (A-4) 66 g of vinylcyclohexane and 1260 g of hexane were charged into a SUS reactor substituted with dry nitrogen, and the temperature was raised to 60 ° C in a sealed state. . Next, 1.0 MPa of ethylene was introduced. Next, 3.0 g of a toluene solution of triisobutylaluminum [manufactured by Tosoh Akzo Co., Ltd., triisobutylaluminum concentration 20 wt%] was charged, followed by dimethylsilyl (tetramethylcyclopentadienyl) (3-tert-butyl- 5-methyl-2-phenoxy) titanium dichloride 0.2 mg dissolved in dehydrated toluene 1.3 g and dimethylanilinium tetrakis (pentafluorophenyl) borate 8 mg dissolved in dehydrated toluene 6.7 g were charged, Polymerization was started. During the polymerization, the polymerization solution was stirred, and ethylene was supplied into the reactor so that the pressure of ethylene was maintained at 1.0 MPa. Six hours after the start of polymerization, 5 g of ethanol was added to the polymerization solution. Next, a 2 wt% hydrochloric acid aqueous solution equivalent to the polymerization solution was added to the polymerization solution, and the aqueous layer and the organic layer were separated. The organic layer was collected and poured into a large amount of acetone, and a cloudy white solid was collected. The solid was washed with acetone and dried under reduced pressure. As a result, 63 g of copolymer (A-4) was obtained. The ethylene unit content of the polymer was 94.7 mol%, and the vinylcyclohexane unit content was 5.3 mol%. Further, only one melting peak was confirmed, the melting point was 99 ° C., the glass transition point was −20 ° C., and [η] was 1.59 dl / g.

[Comparative Example 3] Synthesis of ethylene / vinylcyclohexane copolymer (A-5) 176 g of vinylcyclohexane and 1168 g of hexane were charged into a SUS reactor substituted with dry nitrogen, and the temperature was raised to 60 ° C in a sealed state. . Next, 0.8 MPa of ethylene was introduced. Next, 3.0 g of a toluene solution of triisobutylaluminum [manufactured by Tosoh Akzo Co., Ltd., triisobutylaluminum concentration 20 wt%] was charged, followed by dimethylsilyl (tetrahydroindenyl) (3-tert-butyl-5-methyl). 2-Phenoxy) Titanium dichloride 0.3 mg dissolved in dehydrated hexane 4.0 g and dimethylanilinium tetrakis (pentafluorophenyl) borate 8 mg dissolved in dehydrated hexane 5.4 g were charged to initiate polymerization. did. During the polymerization, the polymerization solution was stirred, and ethylene was supplied into the reactor so that the pressure of ethylene was maintained at 0.8 MPa. 3.5 hours after the start of polymerization, 5 g of ethanol was added to the polymerization solution. Next, a 2 wt% hydrochloric acid aqueous solution equivalent to the polymerization solution was added to the polymerization solution, and the aqueous layer and the organic layer were separated. The organic layer was collected and poured into a large amount of acetone, and a cloudy white solid was collected. The solid was washed with acetone and dried under reduced pressure. As a result, 120 g of copolymer (A-5) was obtained. The polymer had an ethylene unit content of 84.9 mol% and a vinylcyclohexane unit content of 15.1 mol%. Further, only one melting peak was confirmed, the melting point was 40 ° C., the glass transition point was −25 ° C., and [η] was 0.94 dl / g.

  The laminated stretched films of Examples 2-3 and Comparative Examples 1-3 were prepared in the same manner as in Example 1.

It turns out that the film which consists of resin for sealant films of this invention is excellent in low-temperature heat-sealing property compared with the film of the comparative example 1 which consists of a propylene / 1-butene copolymer. On the other hand, since Comparative Example 2 has a low vinylcyclohexane content, only a heat seal temperature comparable to the conventional one can be obtained. On the contrary, Comparative Example 3 has a VCH content that is too high, so that a seal strength of about 250 g can be obtained even at room temperature. The result was unsuitable as a material for sealants.

Claims (4)

  A resin for a sealant film containing 85 to 94 mol% of a repeating unit derived from ethylene and 6 to 15 mol% of a repeating unit derived from a vinyl compound (derived from a repeating unit derived from ethylene and a vinyl compound) The vinyl compound is represented by the structural formula CH2 = CH-R, and the substituent R is an alicyclic hydrocarbon having 3 to 10 carbon atoms. The resin for a sealant film, which represents a group.   The resin for sealant films according to claim 1, wherein the substituent R is a cyclohexyl group. A multilayer film in which the sealant film resin according to claim 1 or 2 is laminated on at least one outermost layer.   The multilayer film according to claim 3, wherein the multilayer film is biaxially stretched.