JPH1180445A - Resin composition with improved color shade and film composed of same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film free from a change in a color shade after film formation, excellent in low temperature sealability, sealing strength, hot tack properties, impact strength and transparency and exhibiting excellent anti- blocking properties and slipping properties. SOLUTION: This polyethylene-based resin composition contains 0.3-5 pts.wt. of an amorphous aluminosilicate with an average particle size of 0.1-10 μm, a pH, of an aqueous dispersion of 5% solid content, of 5.0 or more and less than 8.0 and a refractive index of 1.48-1.52 based on 100 pts.wt. of a polyethylene-based resin with a bending modulus of 2,500 kg/cm<2> or less. There is also provided a film composed of the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has no change in hue after film formation, is excellent in low-temperature sealing property, sealing strength, hot tack property, impact strength and transparency, and has good blocking properties and slipperiness between films. The present invention relates to a resin composition for a film and a film obtained from the composition.

[0002]

2. Description of the Related Art At present, polyethylene resins are used alone or in combination with polyamide resins, polyester resins, polypropylene resins, and ethylene / vinyl alcohol because of their low-temperature sealability, heat seal strength, transparency, flexibility, and impact strength. By being coextruded with another resin such as a united resin, or laminated with a stretched base film such as a polyamide film, polyester film, or polypropylene film, it is widely used for packaging foods, pharmaceuticals, industrial supplies, and the like. Commonly used polyethylene resins include high-pressure low-density polyethylene, high-density polyethylene, and linear low-density polyethylene (hereinafter, LLDPE).
) And ethylene / vinyl acetate copolymer (hereinafter referred to as EV
A) and ethylene / α-olefin copolymers such as ethylene / acrylic acid copolymers. In fields where low-temperature sealability and seal strength are required, ethylene / α-olefins such as LLDPE and EVA are used. Copolymers are mainly used. Due to the recent development of high-speed automatic packaging machines and the demand for stable sealing properties, it has become necessary to impart even lower-temperature sealing properties to polyethylene resins. In order to impart further low-temperature sealing properties, the α-olefin content in the ethylene / α-olefin copolymer may be increased to lower the crystallinity of the resin. This results in a deteriorated film, and the blocking property and the slipperiness between the films are deteriorated, which makes practical use difficult. In order to remedy this drawback, it is necessary to add a large amount of an antiblocking agent such as an inorganic filler. However, redaction, yellowing, etc. are caused by the interaction between the antiblocking agent and other additives such as an antioxidant. Discoloration tends to occur.

[0003]

DISCLOSURE OF THE INVENTION The present invention has no change in hue after film formation, is excellent in low-temperature sealing property, sealing strength, hot tack property, impact strength, transparency, blocking property between films, and slip property. To provide a good resin composition for films and films.

[0004]

Means for Solving the Problems As a result of intensive studies on solving the above problems, the present inventors have found that an anti-blocking agent having a specific property effective for preventing discoloration and blocking of a film and a specific flexural modulus. It has been found that the object of the invention can be achieved by combining an ethylene / α-olefin copolymer having the following formula, and the present invention has been completed. That is, in the present invention, the flexural modulus is 2500
A polyethylene-based resin containing 0.3 to 5 parts by weight of an amorphous aluminosilicate having the following properties (1) to (3) based on 100 parts by weight of a polyethylene-based resin of not more than kg / cm ^2. A composition and a film comprising the composition. (1) Average particle size of 0.1 to 10 μm (2) pH of 5.0 to less than 8.0 when prepared as a 5% solid aqueous dispersion (3) Refractive index of 1.48 to 1.52

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. 1. Polyethylene resin (component A) The polyethylene resin used in the present invention is an ethylene homopolymer or an ethylene / α-olefin copolymer. As the ethylene / α-olefin copolymer, a copolymer of ethylene and an α-olefin having 4 to 18 carbon atoms is preferable. As the α-olefin, butene-1, pentene-1, hexene-1, 4-methyl-1-pentene, octene-1, decene-1, vinyl acetate, (meth)
Acrylic acid, (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate and the like are used, butene-1, hexene-1, and 4-methyl-1 are used.
-Penten, octene-1, vinyl acetate, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate are preferred. Further, two or more of these α-olefins may be used in combination for polymerization, or two or more ethylene / α-olefin copolymers may be blended.

Among the ethylene / α-olefin copolymers of the present invention, ethylene / butene-1 copolymer and ethylene / α-olefin copolymer
Examples of the method for producing LLDPE such as hexene-1 copolymer and ethylene / octene-1 copolymer include a high-pressure radical polymerization method, a high-pressure ionic polymerization method, a gas phase method, a solution method, and a slurry method. High pressure ionic polymerization is preferred.
As the catalyst, a transition metal complex catalyst such as a Ziegler catalyst or a metallocene catalyst is used, but a metallocene catalyst is preferably used.

A specific method for producing the ethylene / α-olefin copolymer in the present invention is described in JP-A-58-1.
No. 9309, No. 59-95292, No. 60-3500
No. 5, No. 60-35006, No. 60-35007,
No. 60-35008, No. 60-35009, No. 61
No. 130314, JP-A-3-1630088, European Patent Application No. 420,436, U.S. Pat. No. 5,055,438, and International Patent Publication WO091 / 04257. The process described is a metallocene catalyst, a metallocene / alumoxane catalyst or, for example, WO092
A metallocene compound as disclosed in JP-A-07 / 07123 and a catalyst comprising a compound which reacts with a metallocene catalyst described below to form a stable ion are used to form ethylene as a main component and carbon number of a subcomponent of 4 And a method of copolymerizing α-olefins of No.

[0008] The compound which becomes a stable ion by reacting with the metallocene catalyst is an ionic compound or an electrophilic compound formed from an ion pair of a cation and an anion. To form polymerization active species. Among them, the ionic compound is represented by the following formula (I). [Q] ^{m +} [Y] ^m− (m is an integer of 1 or more) (I) Q in the formula is a cation component of the ionic compound, and is a carbonium cation, a tropylium cation, an ammonium cation, an oxonium cation, a sulfonium Examples thereof include cations and phosphonium cations, and further include metal cations and organic metal cations which are easily reduced by themselves.

[0009] These cations are disclosed in
Not only a cation capable of giving a proton as disclosed in Japanese Patent Publication No. 50 and 50, but also a cation not providing a proton may be used. Specific examples of these cations include triphenylcarbonium, diphenylcarbonium, cycloheptatrienium, indenium, triethylammonium, tripropylammonium, tributylammonium, N, N-dimethylammonium, dipropylammonium, dicyclohexylammonium, Phenylphosphonium, trimethylphosphonium, tri (dimethylphenyl) phosphonium, tri (methylphenyl) phosphonium, triphenylsulfonium, triphenyloxonium, triethyloxonium, pyrylium, and silver, gold, platinum, palladium, and mercury Ion, ferrocenium ion and the like.

Y is an anionic component of an ionic compound, which is a component which reacts with a metallocene compound to form a stable anion, such as an organic boron compound anion, an organic aluminum compound anion, an organic gallium compound anion, and an organic phosphorus compound. Anions, organic arsenic compound anions, organic antimony compound anions, and the like, specifically, tetraphenylboron, tetrakis (3,4,5
-Trifluorophenyl) boron, tetrakis (3,5
-Di (trifluoromethyl) phenyl) boron, tetrakis (3,5- (t-butyl) phenyl) boron, tetrakis (pentafluorophenyl) boron, tetraphenylaluminum, tetrakis (3,4,5-trifluorophenyl) Aluminum, tetrakis (3,5-di (trifluoromethyl) phenyl) aluminum, tetrakis (3,5-di (t-butyl) phenyl) aluminum, tetrakis (pentafluorophenyl) aluminum, tetraphenylgallium, tetrakis (3 4,
5-trifluorophenyl) gallium, tetrakis (3,5-di (trifluoromethyl) phenyl) gallium, tetrakis (3,5-di (t-butyl) phenyl)
Gallium, tetrakis (pentafluorophenyl) gallium, tetraphenylphosphorus, tetrakis (pentafluorophenyl) phosphorus, tetraphenylarsenic, tetrakis (pentafluorophenyl) arsenic, tetraphenylantimony, tetrakis (pentafluorophenyl) antimony, decaborate, undeca Borate, carbado decaborate, decachloro decaborate and the like.

As the electrophilic compound, among compounds known as Lewis acid compounds, those which react with a metallocene compound to form stable ions to form a polymerization active species, and include various metal halides Examples include compounds and metal oxides known as solid acids. Specific examples include magnesium halides and Lewis acidic inorganic compounds.

Among ethylene / α-olefin copolymers, EVA, ethylene / (meth) acrylic acid copolymer,
Examples of a method for producing a copolymer of ethylene and an α-olefin having a carbonyl group, such as an ethylene / (meth) acrylate copolymer, include high-pressure radical polymerization.

The flexural modulus of the ethylene / α-olefin copolymer used in the present invention is 2500 kg / cm ² or less.
Preferably it is 1000 kg / cm ² or less. If the flexural modulus exceeds 2500 kg / cm ² , the low-temperature heat sealability deteriorates, which is not preferable.

The ratio of the weight average molecular weight Mw to the number average molecular weight Mn of the ethylene / α-olefin copolymer of the present invention, Mw /
Mn (Q value) is 1.5 to 3.0, preferably 1.5 to 3.0.
2.5 is desirable.

The relation between the extrapolated melting end temperature (Tem) and the density (D) of the melting peak obtained by differential scanning calorimetry (DSC) of the ethylene / α-olefin copolymer is as follows: Tem ≦ 286D− 137, preferably Tem
≦ 429D-271, more preferably Tem ≦ 571D
It is desirable to satisfy the relational expression of -404. If Tem is out of the above range, the transparency and sealing property of the film are undesirably hindered.

Further, the ethylene / α-olefin copolymer used in the present invention has a temperature of 190 ° C. according to JIS-K7210.
The melt flow rate (hereinafter, referred to as MFR) measured under the condition of a load of 2.16 kg is not particularly limited as long as it can be formed into a film.
50 g / 10 min, preferably 0.3 to 20 g / 10
min is desirable.

2. Amorphous Aluminosilicate (Component B) The amorphous aluminosilicate used in the present invention needs to satisfy the following properties. Average Particle Size The average particle size of the amorphous aluminosilicate used in the present invention is 0.1 to 10 μm. Average particle size is 0.1
If it is less than μm, the anti-blocking property is not sufficient,
If the thickness exceeds 0 μm, the transparency of the film deteriorates, which is not preferable.

PH The pH of the amorphous aluminosilicate used in the present invention as a water-soluble dispersion of 5% solids is 5.0 or more and less than 8.0, preferably 5.3 or more and 7.6. And more preferably 5.5 or more and less than 7.0. If the pH is out of this range, discoloration of the film tends to occur, which is not preferable.

Refractive index The amorphous aluminosilicate used in the present invention has a refractive index of 1.48 to 1.52. If the refractive index is out of this range, the transparency of the film deteriorates, which is not preferable.

The resin composition of the present invention contains auxiliary additives generally used for resin compositions, such as antioxidants (of which phenol and phosphorus antioxidants are preferred), light stabilizers, Other inorganic or organic antiblocking agents, slip agents, heat stabilizers, ultraviolet absorbers, neutralizing agents, anti-fogging agents, coloring agents, pigments, nucleating agents, etc. can be blended. As the fogging agent, a known film surface coating type anti-fogging agent can be applied.

Further, in order to improve the moldability when forming the film, other ethylene polymers such as high-pressure low-density polyethylene, linear low-density polyethylene, and high-density polyethylene are required. Can be added accordingly. In this case, the amount added is based on the base ethylene-α-
The content is preferably 5 to 15% by weight as long as the toughness of the olefin copolymer is not practically impaired.

The resin composition of the present invention comprises a specific ethylene
It can be obtained by dry blending or melt-kneading an α-olefin copolymer and a specific amorphous aluminosilicate. Various blenders such as a tumbler mixer and a Henschel mixer are used for dry blending. For the melt-kneading, various mixers such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a Brabender plastograph, and a hot roll, and a kneading extruder are used.

A suitable film can be obtained by air-cooled inflation molding, air-cooled two-stage cooling inflation molding, T-die film molding, water-cooled inflation molding, or the like. The film of the present invention may be a single layer or a composite film with any other film-formable substrate.

The base material used is paper, cellophane, woven fabric, aluminum foil, nylon 6, nylon 6
6, polyamide resins such as nylon 11 and nylon 12,
Polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polyethylene, polypropylene, poly-1-butene, ethylene / vinyl acetate copolymer, ethylene / (meth) acrylic acid (ester) copolymer, and polyolefin resins such as ionomers; Examples thereof include polyvinyl chloride, polystyrene, polyvinyl alcohol, and ethylene / vinyl alcohol copolymer.

The composite film of the sealant film and the substrate of the present invention can be obtained by known techniques such as lamination methods such as dry lamination, wet lamination, sand lamination and hot melt lamination, coextrusion methods and extrusion lamination methods, and these techniques. It is manufactured by a combination of

As the co-extrusion method, there are an extruder according to the number of laminations and an air-cooled inflation film forming having a usual feed block type, multi-manifold type, multi-slot type joining / merging portion, T-die film forming, water-cooled inflation A suitable film can be obtained by film forming or the like. Further, the film may be subjected to various processes such as a corona discharge process, a frame process, a stretching process, and a liquid agent application process.

[0027]

The present invention will be described more specifically with reference to the following Examples and Comparative Examples. Measurement of physical properties and evaluation of physical properties of films in Examples and Comparative Examples were performed by the following methods.

1. Method for measuring physical properties (a) MFR: JIS-K7210 (190 ° C, 2.1
6 kg load).

(B) Density: Based on JIS-K7112.

(C) Extrapolation melting end temperature (Tem) by differential scanning calorimetry (DSC): Approximately 5 mg of a sample was weighed from a 100 μm film formed by a hot press, and was weighed by Seiko Denshi Kogyo KK. RDC 220
It was set in a DSC device, heated to 170 ° C., kept at that temperature for 5 minutes, and then cooled to −10 ° C. at a rate of 10 ° C./min. After holding for 1 minute, the temperature is raised at a rate of 10 ° C./min.
The temperature was raised to 70 ° C. for measurement. That is, -10 ° C
To 170 ° C. to obtain a DSC curve. JIS-K
In accordance with 7121, the temperature at the intersection of a line obtained by extending the base line on the high-temperature side of the DSC curve to the low-temperature side and a tangent drawn at the point where the gradient becomes maximum on the high-temperature curve of the melting peak is the extrapolated melting end temperature. (Tem).

(D) Q value: Size Exclusion Chromatog
(Raphy: SEC) under the following measurement conditions, and the Q value was determined from weight average molecular weight Mw / number average molecular weight Mn. A universal calibration curve was created with monodisperse polystyrene and calculated as the molecular weight of linear polystyrene. Model: Waters Model 150C GPC solvent; o-dichlorobenzene Flow rate: 1 ml / min Temperature: 140 ° C Measurement concentration: 2 mg / ml Injection volume: 200 μl Column: Showa Denko KK AD80M / S 3

(E) Flexural modulus; JIS K-7106
It measured according to.

2. Film physical property evaluation method (a) HAZE: Based on JIS K7105.

(B) 300 g load, low temperature heat seal temperature (low temperature heat sealability): Two films of the present invention are stacked so that the untreated surfaces of corona overlap, and the film is heated from 80 ° C. by a hot plate heat sealer manufactured by Toyo Seiki Co., Ltd. Seal pressure at 5 ° C intervals: 2
Heat sealing was performed at 0.5 kg / cm ² , sealing time: 0.5 second, and the heat sealing strength was measured with a tensile tester. The temperature at which the heat seal strength reached 300 g / 15 mm was taken as the heat seal temperature under a load of 300 g and used as a measure of the low-temperature heat sealability.

(C) Hue of film: The film formed according to the example was placed in a constant temperature and humidity chamber of 40 ° C. and 80% humidity and left for one month, and the change in hue of the cross section of the wound film was visually observed. Criteria ；: No change in hue, ×: Discoloration of the film such as yellowing or redness.

3. Film Forming Method A predetermined amount of amorphous aluminosilicate was added to a polyethylene resin, a film was formed by a T-die forming method under the following conditions, and was used for evaluation. Further, the corona discharge treatment machine attached to the apparatus allows the surface tension of the film surface to be 44 to
Corona treatment was performed so as to be 45 dyne / cm. (Molding conditions) Model: Egan T-die film molding machine Screw diameter: 65 mm φ Lip width: 1.2 mm Temperature: 240 ° C. Die effective width: 710 mm Film thickness: 50 μm

Example 1 (1) Preparation of Component A The catalyst was prepared by the method described in JP-A-61-130314. That is, ethylene bis (4,
To 2.0 mmol of 5,6,7-tetrahydroindenyl) zirconium dichloride, methylammonoxane (manufactured by Toyo Stouffer Co., Ltd.) was added at 1000 times the amount of the above complex, and diluted to 10 liter with toluene to prepare a catalyst solution. Polymerization was performed by the following method. A mixture of ethylene and 1-hexene was supplied to a 1.5-liter stirred autoclave continuous reactor so that the composition of 1-hexene became 80% by weight, and the pressure in the reactor was increased to 1300 k.
g / cm ² , and the reaction was carried out at a temperature of 145 ° C. After the completion of the reaction, the MFR was 3.5 g / 10 min, and the density was 0.90.
An ethylene / 1-hexene copolymer having a melting peak of 4 g / cm < ³ > and an extrapolated melting end temperature (Tem) of 103 [deg.] C. of a melting peak by differential scanning calorimetry (DSC) was obtained. Irganox 1076 was added as an antioxidant to the obtained copolymer.
(Ciba-Geigy), P-EPQ (Sand), and erucamide (Nippon Kasei) as slip agents in appropriate amounts to prepare a copolymer composition.

(2) Preparation of Resin Composition Mizusawa Chemical Co., Ltd. was added to Component A obtained above as Component B
Aluminosilicate a (average particle size 2.95)
μm, pH 6.0 of 5% suspension, refractive index 1.5
0) and 1.2 parts of component B per 100 parts by weight of component A.
The mixture was blended in parts by weight, T-die molding was performed under the above conditions, and a film was formed and evaluated. The results of the evaluation are as shown in Table 1.

Example 2 As Component A, LV360 (MF, manufactured by Nippon Polychem Co., Ltd.) was used.
R; 3.5 g / 10 min, vinyl acetate content 11% by weight)
Using ethylene / vinyl acetate copolymer of the formula (1).
A film was prepared and evaluated in the same manner as in Example 1 except that the amount was 8 parts by weight. The results of the evaluation are as shown in Table 1.

Comparative Example 1 Amorphous aluminosilicate b manufactured by Mizusawa Chemical Co., Ltd. (average particle size: 2.82 μm, pH of 7.8 with 5% suspension, refractive index: 1.47) was used as Component B, except that A film was prepared and evaluated in the same manner as in Example 1. The results of the evaluation are as shown in Table 1.

Comparative Example 2 Amorphous aluminosilicate JC-30 (average particle diameter: 3.06 μm, 5% suspension pH: 11.1, refractive index: 1.50) manufactured by Mizusawa Chemical Co., Ltd. was used as Component B. Except for the above, a film was prepared and evaluated in the same manner as in Example 1. The results of the evaluation are as shown in Table 1.

Comparative Example 3 Amorphous aluminosilicate JC-30 (average particle size: 3.06 μm, 5% suspension pH: 11.1, refractive index: 1.50) manufactured by Mizusawa Chemical Co., Ltd. was used as Component B. Except for the above, a film was prepared and evaluated in the same manner as in Example 2. The results of the evaluation are as shown in Table 1.

Comparative Example 4 As component A, an ethylene / hexene-1 copolymer (MFR: 2.0 g / 10) of SF240 manufactured by Nippon Polychem Co., Ltd.
Min, density: 0.920 g / cm ³ , extrapolation melting end temperature of melting peak by differential scanning calorimetry (DSC) (Te
m): 129 ° C.), and as component B, amorphous aluminosilicate a manufactured by Mizusawa Chemical Co., Ltd. (average particle diameter: 2.95 μm, pH 6.0 of 5% suspension, refractive index: 1.50) , Component B with respect to 100 parts by weight of Component A
Was blended at a ratio of 0.3 parts by weight, and T-die molding was performed under the above conditions to form a film, which was evaluated. The evaluation results are as shown in Table 1.

[0044]

[Table 1]

[0045]

The resin composition of the present invention is a polyethylene resin composition obtained by combining an antiblocking agent having a specific property effective for preventing blocking and an ethylene / α-olefin copolymer having a specific flexural modulus. With no change in hue after film formation, a film having excellent low-temperature sealing properties, sealing strength, hot tack properties, impact strength, and transparency, and having good blocking properties and slipperiness between films can be obtained.

Claims (5)

[Claims] The present invention relates to the following (1) to 100 parts by weight of a polyethylene resin having a flexural modulus of 2500 kg / cm ² or less.
Amorphous aluminosilicate 0.3 having the properties of (3)
What is claimed is: 1. A polyethylene-based resin composition comprising about 5 parts by weight. (1) Average particle size of 0.1 to 10 μm (2) pH of 5.0 to less than 8.0 when prepared as a 5% solid aqueous dispersion (3) Refractive index of 1.48 to 1.52 2. A polyethylene resin having a flexural modulus of 10
2. The polyethylene resin composition according to claim 1, wherein the composition is not more than 00 kg / cm ² . 3. The polyethylene resin composition according to claim 1, wherein the polyethylene resin satisfies the following properties. The ratio of the weight average molecular weight Mw to the number average molecular weight Mn, Mw /
Mn is 1.5 to 3.0 4. The polyethylene resin composition according to claim 1, wherein the polyethylene resin satisfies the following properties. The relationship between the extrapolated melting end temperature (Tem) and density (D) of the melting peak obtained by differential scanning calorimetry (DSC) satisfies the following relational expression. Tem ≦ 286D-137 5. A film comprising the resin composition according to claim 1.