JP2001151947A - Polyolefin resin composition and film made thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition which is free from foaming when molded, gives a molded article excellent in thickness accuracy, and comprises a polyolefin resin and a surfactant and to provide a film obtained by the inflation of the resin composition. SOLUTION: The resin composition comprises 100 pts.wt. polyolefin resin and 0.1-5 pts.wt. surfactant and has a water content of 200-1,000 ppm. The film is obtained by the inflation of the resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polyolefin resin composition and a film comprising the resin composition and obtained by inflation processing. More specifically,
The present invention relates to a polyolefin-based resin composition having no foaming during molding and having excellent thickness accuracy of a molded article, and a film comprising the resin composition and obtained by inflation.

[0002]

2. Description of the Related Art Polyolefin resins are excellent in tensile strength, transparency, chemical resistance, workability and the like and are inexpensive, so that they are used in large quantities as various packaging materials. However, polyolefin resins are not hydrophilic and are easily charged and easily generate static electricity.Therefore, when used as a packaging film, there are problems such as water droplets and dust adhering to the film, making it difficult to see inside and impairing the appearance. there were.

As a method for preventing the adhesion of water droplets and the generation of static electricity, a method of blending an antifogging agent and an antistatic agent with a polyolefin resin, particularly a method of blending a surfactant as an antifogging agent and an antistatic agent is known. Are known. For example, JP-A-58-63737 discloses an antistatic method for a polyolefin resin in which an amine stearate or a mixture of an amine stearate and an alkane sulfonate is added as an antistatic agent to the polyolefin resin. .
JP-A-9-3273 discloses an antistatic composition for polypropylene in which diglycerin fatty acid ester is added to polypropylene. In addition, Japanese Patent Application Laid-Open
No. 1571 discloses an agricultural polyolefin resin composition obtained by adding a nonionic surfactant and an alkyl sulfonate as antifogging agents to a polyolefin resin.

However, in these methods, the antifogging agent and the antistatic agent contained in the resin absorb moisture and the resin contains a large amount of water. The appearance was sometimes poor. Therefore, the resin composition containing an anti-fogging agent and an antistatic agent is dried to remove water, and then devised such as molding. However, if the water contained in the resin composition is too small, especially inflation processing is performed. However, there were problems such as inflation bubbles becoming unstable, causing wrinkles, and the film thickness not being constant.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin composition comprising a polyolefin resin and a surfactant, which does not foam during resin molding and has excellent thickness accuracy of a molded article, and a resin composition thereof. And to provide a film obtained by inflation.

[0006]

In view of such a situation,
The present inventors have conducted intensive studies on the above problems, and as a result,
The inventors have found that the above problems can be solved by adding a specific amount of water to a resin composition comprising a polyolefin-based resin and a surfactant, and have completed the present invention.

That is, the present invention relates to a resin composition having a surfactant content of 0.1 to 5 parts by weight and a water concentration of 200 to 1000 ppm based on 100 parts by weight of a polyolefin resin, and inflation of the resin composition. It relates to a film obtained by processing. Hereinafter, the present invention will be described in detail.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The polyolefin resin used in the present invention mainly comprises a homopolymer, copolymer or α-olefin having 2 to 8 carbon atoms of α-olefin having 2 to 8 carbon atoms. A copolymer as a component is exemplified, and the content of the repeating unit derived from an α-olefin having 2 to 8 carbon atoms usually exceeds 50% by weight. α-
Examples of the olefin include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene and the like.

Examples of the homopolymer of an α-olefin having 2 to 8 carbon atoms include ethylene homopolymer, propylene homopolymer, 1-butene homopolymer, 1-hexene homopolymer, and 1-octene homopolymer. Polymers.
Preferred are ethylene homopolymer and propylene homopolymer.

Examples of the copolymer of an α-olefin having 2 to 8 carbon atoms include ethylene-1-butene copolymer, ethylene-1-hexene copolymer, and ethylene-1-olefin.
Octene copolymer, propylene-ethylene copolymer, propylene-1-butene copolymer, propylene-1-hexene copolymer, propylene-ethylene-1-butene copolymer, propylene-ethylene-1-hexene copolymer Coalescing,
Ethylene-1-butene-1-hexene copolymer and the like. Preferred are ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, and propylene-ethylene copolymer.

[0011] Copolymers containing an α-olefin having 2 to 8 carbon atoms as a main component include α-olefins having 2 to 8 carbon atoms.
A copolymer with at least one monomer of an olefin and at least one monomer selected from an ester group-containing vinyl compound, an unsaturated carboxylic acid or an ionomer thereof, a vinyl aromatic compound, a diene compound or a cyclic olefin; And hydrogenated products thereof in the copolymer containing a diene compound.

As these monomers, for example, ester group-containing vinyl compounds include vinyl esters such as vinyl acetate and vinyl propionate and unsaturated carboxylic esters such as methyl acrylate, ethyl acrylate, methyl methacrylate and ethyl methacrylate. And the like, and examples of the unsaturated carboxylic acid or its ionomer include acrylic acid, methacrylic acid, sodium acrylate, and sodium methacrylate; and examples of the vinyl aromatic compound include styrene and α-methylstyrene. And diene compounds such as butadiene, isoprene, 1,3-
Examples include pentadiene and 2,5-norbornadiene, and examples of the cyclic olefin include 2-norbornene and 5-norbornene.
Methyl-2-norbornene and the like.

Examples of the copolymer mainly containing an α-olefin having 2 to 8 carbon atoms include ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer and ethylene-acrylic acid copolymer. Copolymer, ethylene-sodium acrylate copolymer, ethylene-styrene copolymer, propylene-styrene copolymer, ethylene-butadiene copolymer, propylene-butadiene copolymer, ethylene-2-norbornene copolymer, propylene- A 2-norbornene copolymer is exemplified. Preferably, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ethylene-styrene copolymer, ethylene-
It is a 2-norbornene copolymer.

The method for producing the polyolefin resin used in the present invention is a known polymerization method using a known olefin polymerization catalyst, for example, a radical polymerization initiator, a Ziegler-Natta catalyst, a complex such as a metallocene complex or a non-metallocene complex. , A slurry polymerization method, a solution polymerization method, a bulk polymerization method, a gas phase polymerization method and the like using a catalyst system comprising

The surfactant used in the present invention is added for imparting anti-fogging property and antistatic property, and includes a nonionic surfactant, an anionic surfactant and a cationic surfactant. Agents and amphoteric surfactants.

The nonionic surfactants used in the present invention include polyhydric alcohol fatty acid esters, polyethylene glycol alkyl ethers and the like. Polyhydric alcohol fatty acid esters are defined as at least one polyhydric alcohol and at least one carbon atom having 2 to 24 carbon atoms.
These are esters made from fatty acids. Examples of the polyhydric alcohol include glycerin, diglycerin, polyglycerin, sorbitan, sorbitol, propylene glycol, polypropylene glycol, polyethylene glycol, pentaerythritol, trimethylolpropane, and the like, preferably glycerin, diglycerin or sorbitan, Particularly preferred is diglycerin. Accordingly, particularly preferred polyhydric alcohol fatty acid esters include diglycerin and C2-24
These are esters made from fatty acids.

The fatty acids having 2 to 24 carbon atoms include:
For example, caprylic acid, capric acid, lauric acid, palmitic acid, stearic acid, oleic acid, behenic acid, erucic acid, linoleic acid, ricinoleic acid and the like can be mentioned, and oleic acid or lauric acid is preferable.

These polyhydric alcohols and those having 2 carbon atoms
Esters made from ~ 24 fatty acids include, specifically, glycerin monooleate, glycerindiolate, glycerin monoacetomonostearate, diglycerin monolaurate, diglycerin dilaurate, diglycerin monooleate, diglycerin Examples include geolate and sorbitan oleate.

Particularly preferred are diglycerin monolaurate, diglycerin dilaurate, diglycerin monooleate and diglycerindiolate.

The polyethylene glycol alkyl ethers are esters made from polyethylene glycol and alcohol and / or polyhydric alcohol. Specifically, polyethylene glycol lauryl alcohol ether, polyethylene glycol stearyl alcohol ether, polyethylene glycol nonyl phenyl ether and the like are exemplified. Preferred are polyethylene glycol lauryl alcohol ether and polyethylene glycol stearyl alcohol ether.

As the anionic surfactant, carboxylate, sulfonate, sulfate, phosphate and the like can be used. Examples of the carboxylate include sodium laurate, sodium stearate,
Examples include potassium laurate and potassium stearate.

Examples of the sulfonate include sodium stearyl sulfonate, sodium lauryl sulfonate, sodium dodecyl benzene sulfonate, sodium dodecyl naphthalene sulfonate, potassium stearyl sulfonate, potassium lauryl sulfonate, dibutyl sodium sulfosuccinate, and disulfonic sulfosuccinate. Sodium 2-ethylhexyl, disodium lauryl sulfosuccinate, lauryl polyoxyethylene sulfosuccinate 2
Sodium and the like.

Examples of the sulfate salt include sodium lauryl sulfate and potassium lauryl sulfate, and examples of the phosphate ester salt include sodium lauryl phosphate and
And potassium lauryl phosphate.

As the cationic surfactant, a quaternary ammonium salt, an amine salt, a pyridinium salt and the like can be used. As the quaternary ammonium salt, for example,
Stearyl trimethyl ammonium chloride, octadecyl trimethyl ammonium chloride, dodecyl trimethyl ammonium chloride and the like can be mentioned.

Examples of the amine salt include octadecylamine acetate, tetradecylamine acetate and the like.

As the amphoteric surfactant, betaine type, imidazoline type, alanine type and the like can be used.
For example, dimethylstearylbetaine, dimethyllaurylbetaine, dihydroxylaurylbetaine and the like can be mentioned.

The amount of the surfactant used in the present invention is 0.1 to 100 parts by weight of the polyolefin resin.
5 parts by weight. If the amount is less than 0.1 part by weight, the antifogging property and the antistatic property may be insufficient. If the amount exceeds 5 parts by weight, it is preferable to use a resin composition which is a master batch.
Preferably it is 0.5 to 4 parts by weight, more preferably 1 to 3 parts by weight.

The concentration of water used in the present invention is 200 to 1000 ppm in the resin composition. If the content is less than 200 ppm, the film slips on the stabilizer during the inflation molding process, and the inflation bubbles are caught on the stabilizer, and as a result, the film thickness does not become constant,
The film may be wrinkled. Also, 10
If it exceeds 00 ppm, the moisture contained in the resin composition may foam and the appearance of the film may deteriorate. Preferably 300 to 800 ppm, more preferably 400 to 700
ppm.

The method for adjusting the concentration of water used in the present invention is as follows.
There is no particular limitation, and a known method can be used. For example, a resin composition was extruded into water using an extruder, cut and pelletized, and then dried or humidified to adjust the water concentration, and the resin composition was extruded into the air using an extruder. After that, put in a water tank, take out again in the air, cut and pelletize, in the method of adjusting the amount of water by adjusting the time to keep the resin composition in the water tank, in the above-described method, pelletized Then, drying or humidification is performed to adjust the water concentration.

As a method for measuring the water concentration in the resin composition of the present invention, for example, the Karl Fischer method is used. The Karl Fischer method is a method in which a sample is heated to drive out water, the generated water is introduced into a Karl Fischer liquid by a nitrogen gas flow, and the water is quantified by the principle of titration or electrolysis.

The method for preparing the resin composition of the present invention is not particularly limited, and a known method can be used. For example, a method of melting and kneading each component by heating and the like can be mentioned. The heat-melt kneading can be carried out using a kneader such as a kneader, a Banbury mixer, a roll, or a single-screw or twin-screw extruder.

The resin composition of the present invention may optionally contain, as long as the object and effects of the present invention are not impaired,
Other additives and fillers such as antioxidants, anti-blocking agents, lubricants, nucleating agents, flame retardants and the like can be added.

The processing method of the resin composition of the present invention includes:
An inflation process is preferred, and an air-cooled inflation process is more preferred. In addition, although either a single layer processing method or a multilayer processing method can be used, in the case of a multilayer processing method, it is desirable to use the resin composition of the present invention for a layer in contact with a stabilizer.

The thickness of the film is preferably the thickness of a thin material, preferably 50 μm or less, more preferably 30 μm or less.
μm or less, most preferably 20 μm or less. The accuracy of the film thickness is determined as the ratio of the difference between the maximum thickness and the minimum thickness to the average thickness of the film, that is, (maximum thickness−minimum thickness) / average thickness, and is preferably 45% or less,
It is more preferably at most 35%.

[0035]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

First, methods for measuring physical properties in the following examples and comparative examples will be described. (1) Melt flow rate (MFR) Measurement was performed in accordance with JIS K6924-2: 1997. (2) Vinyl acetate content (VA) The measurement was performed according to JIS K6924-2: 1997. (3) Moisture Content Using a moisture vaporizer VA-05, manufactured by Mitsubishi Chemical Corporation, and a trace moisture analyzer CA-05, measurement was performed at a moisture vaporization temperature of 180 ° C., a delay time of 10 minutes, and a nitrogen flow rate of 100 ml / min. .

(4) Evaluation of Film Processing A 20 μm thick blown film was formed at a processing temperature of 200 ° C. using an inflation processing machine.
The presence or absence of foaming of the formed film and the degree of wrinkling of the film winding were visually determined. In addition, the film thickness at 10 or more locations is measured using a micro gauge to determine the average film thickness, and the ratio of the difference between the maximum thickness and the minimum thickness to the average thickness ((maximum thickness−minimum thickness) / average thickness) is determined. The accuracy of the film thickness was used.

Example 1 Polyolefin resin (Ethylene-vinyl acetate copolymer Evatate H2081 manufactured by Sumitomo Chemical Co., Ltd. MFR =
2 g / 10 min, VA = 16% by weight) 100 parts by weight, nonionic surfactant (STO-40 manufactured by Marubishi Yuka Kogyo Co., Ltd.)
5) After extruding 2 parts by weight from the extruder into the air,
The resin composition was put in a water tank for 18 seconds, taken out into the air again, and cut to obtain a resin composition having a water concentration of 490 ppm. The obtained resin composition was blown to obtain a film. Table 1 shows the evaluation results of the film.

Comparative Example 1 Polyolefin resin (Ethylene-vinyl acetate copolymer Evatate H2081 MFR = manufactured by Sumitomo Chemical Co., Ltd.)
2 g / 10 min, VA = 16% by weight) 100 parts by weight, nonionic surfactant (STO-40 manufactured by Marubishi Yuka Kogyo Co., Ltd.)
5) After extruding 2 parts by weight from the extruder into the air,
The resin composition was placed in a water tank for 2 seconds, taken out into the air again, and cut to obtain a resin composition having a water concentration of 170 ppm. The obtained resin composition was blown to obtain a film. Table 1 shows the evaluation results of the film.

Comparative Example 2 The resin composition obtained in Comparative Example 1 was left in the air for 2 weeks to obtain a resin composition having a water concentration of 1400 ppm. The obtained resin composition was blown to obtain a film. Table 1 shows the evaluation results of the film.

It can be seen that the resin compositions of the examples of the present invention, when used in a film, are free from foaming and wrinkling during molding and have excellent thickness accuracy. On the other hand, when the resin composition of Comparative Example 1 which does not satisfy the water concentration which is one of the requirements of the present invention is used for a film, wrinkles are generated, the thickness accuracy is insufficient, and the resin composition of Comparative Example 2 It can be seen that the resin composition foams during molding.

[0042]

[Table 1]

[0043]

As described above in detail, according to the present invention, it is possible to provide a polyolefin-based resin composition which does not foam when molded and has excellent thickness accuracy of a molded article. Further, the resin composition of the present invention can be applied to various uses such as films and sheets which require anti-fogging property and antistatic property.

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Claims (5)

[Claims] 1. A resin composition comprising a surfactant in an amount of 0.1 to 5 parts by weight and a water concentration of 200 to 1000 ppm based on 100 parts by weight of a polyolefin resin. 2. The method according to claim 1, wherein the water concentration is 300 to 800.
ppm. 3. A resin composition comprising the surfactant according to claim 1 in an amount of 0.5 to 4 parts by weight. 4. The resin composition according to claim 1, wherein the surfactant is a nonionic surfactant. 5. A film obtained by inflation processing of the resin composition according to claim 1.