JP3346240B2 - High speed molding method of T-die cast film and its film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a T-die cast film at a high speed, and to the film.

[0002]

2. Description of the Related Art In recent years, packaging materials using plastic films have been evaluated for their characteristics, such as ease of handling, and the demand for such materials has been dramatically increased. Above all, demand for olefin-based resins excellent in various physical properties such as impact strength, tear strength and heat sealing properties has been remarkably increased, and improvements have been made with the aim of improving production efficiency. Methods for increasing the production efficiency include increasing the width of the die (film) and increasing the speed of film forming. However, in the case of an olefin resin, it is easy to cause sharkskin or melt fracture even at a relatively low shear rate, and the There is a limit to the molding speed because the film edge tends to be unstable between the die exit and the chill roll (between the air gaps) during molding.
Mainly, the die width has been increased. However, there is a limit in widening the film due to the problem of quality stability in the width direction of the film, and there has been a strong demand for improvement in high-speed moldability in order to further improve production efficiency.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming a multilayer film having excellent high-speed processability by a T-die cast film forming machine, and a film having high transparency and excellent appearance. Is to do.

[0004]

Means for Solving the Problems The inventors of the present invention have studied for a long time a method of producing a T-die cast film having excellent high-speed moldability using an olefin resin composition, and have studied a specific olefin resin. The present inventors have found that the object of the present invention is achieved by extruding a layer composed of the composition on the chill roll surface side of a T-die cast film production apparatus, and have completed the present invention.

That is, the present invention relates to an olefin resin 1
A method for forming a multilayer film having at least one layer comprising an olefin-based resin composition containing 00 parts by weight and 0.2 to 2.0 parts by weight of fine particles having a weight average particle diameter of 8 to 20 μm, wherein the resin This is a high-speed forming method of a T-die cast film, characterized by extruding a layer made of a composition toward a chill roll surface. Further, the present invention is a T-die cast film obtained by the above high-speed molding method. Hereinafter, the present invention will be described in detail.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The olefin resin used in the present invention includes an ethylene polymer, a propylene polymer and the like. Among them, an ethylene polymer is preferred. Examples of the ethylene-based polymer include an ethylene homopolymer and a copolymer of an ethylene unit and one or more α-olefin units having 3 to 20 carbon atoms, a diolefin unit, and the like. As these copolymer components, for example, propylene,
Butene-1, pentene-1, hexene-1, heptene-
1, octene-1, nonene-1, decene-1, hexadecene-1, eicosene-1, 4-methyl-pentene-
1,4-methyl-hexene-1, vinylcyclohexane, vinylcyclohexene, styrene, norbornene,
Butadiene, isoprene and the like. The content of the above copolymer component is usually 2 to 25% by weight. The density of the ethylene-α-olefin copolymer is usually 0.900
Is a ~0.940g / cm ^3.

[0007] Of these, an ethylene polymer produced by a catalyst containing a transition metal compound, particularly an ethylene polymer produced in the presence of a catalyst containing a transition metal compound having a group having a cyclopentadiene-type anion skeleton is preferable. Among them, an ethylene-α-olefin copolymer is more preferable. The transition metal compound is a so-called metallocene compounds, usually, the general formula ML _a X _na (wherein, M is a transition metal atom of Group 4 or Lanthanide series of the Periodic Table of Elements .L is cyclopentadiene A group having an anion skeleton or a group containing a hetero atom, at least one of which is a group having a cyclopentadiene-type anion skeleton.
May be cross-linked to each other. X is a halogen atom, hydrogen or a hydrocarbon group having 1 to 20 carbon atoms. n represents the valence of the transition metal atom, and a is an integer satisfying 0 <a ≦ n. ) And can be used alone or in combination of two or more. Further, the catalyst may include an organoaluminum compound containing an alumoxane compound and / or an ionic compound such as trityl borate and anilinium borate, and / or SiO ₂ ,
A particulate carrier including an inorganic carrier such as Al ₂ O _{3 and} an organic polymer carrier such as an olefin polymer such as ethylene and styrene is used in combination. The polymerization method is not particularly limited, and examples thereof include a gas phase polymerization method, a liquid phase polymerization method, and a high pressure ionic polymerization method, and a gas phase polymerization method is particularly preferable.

The olefin resin used in the present invention can be blended with various resins according to the purpose. For example, blend high pressure low density polyethylene to improve melt tension and transparency, blend high density polyethylene to improve stiffness, and blend low density elastomer to improve impact strength. be able to. The blending method is not particularly limited,
For example, melt blending using an extruder or dry blending in the form of pellets using a tumbler or the like can be mentioned. The blend ratio is such that the olefin resin component is at least 50% by weight, more preferably at least 60% by weight, and most preferably at least 7% by weight.
0% by weight or more.

The fine particles used in the present invention have a weight average particle diameter in the range of 8 to 20 μm, preferably in the range of 8 to 15 μm. When the weight average particle diameter is smaller than 8 μm,
Stable high-speed processability cannot be obtained. On the other hand, when the weight-average particle size exceeds 20 μm, the transparency of the film is reduced and the appearance of the film surface is deteriorated.
Here, the weight average particle diameter of the fine particles refers to an average particle diameter based on the weight measured using a Coulter counter.

The fine particles used in the present invention are contained in an amount of 0.2 to 2.0 parts by weight, preferably 0.5 to 1.5% by weight, based on 100 parts by weight of the olefin resin. If the amount is less than 0.2 parts by weight, stable high-speed workability cannot be obtained,
When the amount exceeds 2.0 parts by weight, the transparency of the film is reduced, and the appearance of the film surface is deteriorated. A refractive index nD measured at 25 ° C. of 1.45 to 1.5
Fine particles in the range of 8 are preferred. The refractive index of the fine particles here is measured by the Larsen oil immersion method. Specific examples of the fine particles include powders obtained by copolymerizing a raw material monomer and a crosslinker monomer that give various polymer powders, and further, by copolymerizing with one or more other monomers, for example, a crosslinked polymethacrylic acid. Methyl acrylate, cross-linked poly (methyl methacrylate-styrene), cross-linked silicone,
Organic fine particles such as cross-linked polystyrene, and inorganic fine particles such as synthetic aluminosilicate, silica, diatomaceous earth, and talc powders are exemplified. Among these, organic fine particles are preferable. Further, among organic fine particles, a crosslinked polymethyl methacrylate resin powder is preferable. These particles are
A commercially available product that meets the requirements of the present invention can be selected. Commercially available organic fine particles include, for example, "Matsumoto Microsphere-M" (manufactured by Matsumoto Yushi Co., Ltd.), "Julima MB-SX" (manufactured by Nippon Pure Chemical Co., Ltd.), and "Eposter MA" (Nippon Shokubai Co., Ltd. Co., Ltd.). Commercially available inorganic fine particles include, for example, "Silton JC"
(Made by Mizusawa Chemical Co., Ltd.), "SATINTONEW" (EN
GELHARD CORPORATION).

The olefin resin composition used in the present invention can be obtained by melt-blending an olefin resin and fine particles,
It can be obtained by, for example, dry-blending a master batch in which an olefin-based resin and fine particles are melt-mixed at a high concentration in advance to a predetermined concentration. Various blenders such as a Henschel mixer and a tumbler mixer are used for dry blending, and various mixers such as a single screw extruder, a twin screw extruder, a Banbury mixer and a hot roll are used for melt blending.

The high-speed method for forming a T-die cast film according to the present invention is a method for forming a multilayer film having at least one layer comprising the olefin resin composition,
In addition, this is a molding method in which a layer made of the olefin-based resin composition is extruded toward the chill roll surface side, and this is cooled and solidified. When a layer made of the olefin-based resin composition is extruded to a surface opposite to a chill roll surface, high-speed processability cannot be achieved. In the case of a single-layer film extruded from the olefin-based resin composition alone, transparency and appearance of the film are deteriorated.

The high-speed workability referred to in the present invention is 150 m /
When the film is cooled and solidified by a chill roll rotating for more than a minute, the film edge portion does not cause an unstable phenomenon and can be processed stably.

The T-die cast film manufacturing apparatus used in the high-speed molding method of the present invention is not particularly limited, and may be a known T-die cast film manufacturing apparatus. FIG. 1 is a partial schematic diagram illustrating an example of a T-die cast film manufacturing apparatus. The olefin-based resin composition is supplied from the hopper 1, melt-kneaded by the extruder 2, supplied to the die 3, and extruded from the slit having a width of about 0.4 to 3 mm toward the chill roll 5 side. Since the film immediately after being extruded from the die 3 is in a molten state and has a large thickness, the film is stretched to a constant thickness by the chill roll 5 and the air chamber 4 and solidified by cooling. Cooled and solidified film 6
Is wound by a take-up roll and a winder (not shown). In FIG. 1, only a hopper and an extruder for forming a layer made of an olefin-based resin composition are described, and a hopper and an extruder for a layer coextruded on the side opposite to the chill roll surface side are omitted. .

The thermoplastic resin coextruded together with the olefin resin composition on the side opposite to the chill roll side is not particularly limited, and includes, for example, an ethylene polymer. Among ethylene polymers, an ethylene-α-olefin copolymer composed of ethylene and an α-olefin having 3 to 12 carbon atoms is preferable. Further, the thermoplastic resin may contain 0.2 to 2.0 parts by weight of an anti-blocking agent having a weight average particle diameter in a range of 1 to 7 μm based on 100 parts by weight of the thermoplastic resin. .

In the high-speed method for forming a T-die cast film according to the present invention, the film is cooled and solidified by a chill roll, an air chamber, a vacuum chamber,
An air knife or a combination thereof is used.
Among them, it is preferable to use an air chamber.

In order to further improve the physical properties, 2,6-di-t-butyl-p-cresol (BHT),
Tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane (IRGANOX1010), n-octadecyl-3-
A phenolic antioxidant represented by (4'-hydroxy-3,5'-di-t-butylphenyl) propionate (IRGANOX1076); bis (2,4-di-t)
Phosphite-based antioxidants represented by -butylphenyl) pentaerythritol diphosphite, tris (2,4-di-butylphenyl) phosphite, etc .;
Antistatic agents such as fatty acid glycerin ester, sorbitan acid ester, polyethylene glycol ester, etc .; unsaturated fatty acid amides represented by oleic acid amide, erucic acid amide; ethylene bisoleic acid amide;
A lubricant such as an unsaturated fatty acid bisamide represented by methylenebisoleic acid amide may be added.

Additives such as antioxidants, antistatic agents, lubricants and the like to be blended according to various purposes may be melt-kneaded in advance and then subjected to film processing, or may be individually dry blended or one or more kinds. A masterbatch may be used for film processing after dry blending, and any method may be used.

The T-die cast multilayer film obtained by the high-speed molding method of the present invention can be used as a raw material for dry lamination on a substrate such as another plastic film.

[0020]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, the following T-die cast film forming conditions were used as common conditions. (1) Apparatus: Air chamber type co-extrusion T-die film processing apparatus (2) Die width: 1250 mm width, gap: 2.0 m
mt (3) Film thickness: 30 μm (4) Extruder, die set temperature: 240 ° C. (5) Chill roll temperature: 40 ° C. (6) Air chamber pressure: 30 mmAq

The evaluation method was as follows. (1) High-speed processability The maximum chill roll rotation speed at which the film edge did not cause instability was read. (2) Haze (transparency) Measured according to ASTM D1003-61. (3) Film appearance After conditioning the formed film at 23 ± 2 ° C. and 50 ± 5% RH for 24 hours or more, the fine particles contained in the formed film were observed, and the relative prominence of the fineness was compared. Pass / Fail was determined as described above.・ ・ ・: The fine particles were extremely inconspicuous and the appearance was good. Δ: The fine particles looked like small fish eyes and were slightly noticeable. X: Fine particles appeared as small fish eyes, many were scattered and conspicuous on one surface of the film, and the appearance was poor. (4) Weight average particle size Coulter counter model TA- manufactured by Nikkaki Co., Ltd.
Using II, aperture diameter 20 μm or 200 μm,
The measurement was performed with the electrolytic solution ISOTON II. (5) Refractive index of fine particles Measured by the Larsen oil immersion method. Adjustment of Solvent α-Bromnaphthalene (n = 1.660 / 25 ° C.) and Kerosene (n = 1.443 / 25 ° C.) are mixed on a volume basis and the refractive index is increased from 1.4817 to 1.5907 in 0.005 steps. Was prepared. Measurement A few milligrams of the microparticles were placed on a slide glass, covered with a cover glass, the solvent was infiltrated from the gap, and observed with an optical microscope using transmitted light. The refractive index at which the boundary of the fine particles became invisible (hard to see) was defined as the refractive index of the fine particles.

The following were used as samples used in the following Examples and Comparative Examples. (1) Olefin-based resin (i) PO-1 metallocene catalyst-based ethylene-hexene-1 copolymer (Sumikasen E FV403 manufactured by Sumitomo Chemical Co., Ltd.)
Density = 0.919 g / cm ³ , melt flow rate =
(4.0 g / 10 min) (2) Fine particles (i) Fine particles Crosslinked poly (methyl methacrylate) resin powder (Nippon Shokubai Co., Ltd.)
Manufactured by Eposter MA1010, trade name, weight average particle size =
10.0 μm, nD (25 ° C.) = 1.490) (ii) Fine particles synthetic aluminosilicate (trade name JC manufactured by Mizusawa Chemical Co., Ltd.)
−50, weight average particle size = 4.9 μm, nD (25 ° C.)
= 1.490) (3) Unsaturated fatty acid amide (i) SA-1 Erucamide

Example 1 As layer A contacting a chill roll, 100 parts by weight of PO-1, 0.7 parts by weight of fine particles and 0.02 part of SA-1
6. Layer thickness of olefin resin composition containing parts by weight
A resin composition containing 100 parts by weight of PO-1, 0.7 parts by weight of particles, and 0.02 parts by weight of SA-10 as a layer B adjacent to the layer A, extruded under molding conditions specified to be 5 μm. The product was extruded under the specified molding conditions so as to have a layer thickness of 22.5 μm, and a T-die cast film consisting of two layers, Layer A / Layer B, was formed. Table 1 shows the evaluation results.

COMPARATIVE EXAMPLE 1 Using only an olefin resin composition containing 100 parts by weight of PO-1, 0.7 parts by weight of fine particles, and 0.02 parts by weight of SA-1 was extruded under a specified molding condition into a single layer. Was molded. Table 1 shows the evaluation results.

COMPARATIVE EXAMPLE 2 A single layer was extruded using only an olefin resin composition containing 100 parts by weight of PO-1, 0.7 parts by weight of fine particles and 0.02 parts by weight of SA-1 under specified molding conditions. Was molded. Table 1 shows the evaluation results.

[0026]

Table 1------------------------------------Example 1 Comparative Example 1 Comparative Example 2 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Maximum processing speed (m / min) 200 200 120 Haze (%) 4.0 6.4 3. 8 Appearance ○ × ○ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

[0027]

As described in detail above, according to the present invention,
It is possible to provide a high-speed molding method of a T-die cast film which is remarkably excellent in high-speed processability as compared with the conventional method. Further, the present invention can provide a T-die cast film having high transparency and excellent appearance by the above high-speed molding method.

[Brief description of the drawings]

FIG. 1 is a partial schematic view showing an example of a T-die cast film manufacturing apparatus.

[Explanation of symbols]

1 ... hopper, 2 ... extruder, 3 ... die,
4 ... air chamber 5 ... chill roll, 6 ... film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI // C08L 23/04 C08L 23/04 B29K 23:00 B29K 23:00 433: 04 433: 04 B29L 9:00 B29L 9:00 (56) References JP-A-7-178786 (JP, A) JP-A-5-194793 (JP, A) JP-A-6-91829 (JP, A) JP-A-8-67782 (JP, A) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 47/00-47/96 B29C 41/00-41/52 B32B 27/00-27/42 C08L 23/00-23/36

Claims (8)

(57) [Claims] 1. A multilayer film having at least one layer of an olefin resin composition containing 100 parts by weight of an olefin resin and 0.2 to 2.0 parts by weight of fine particles having a weight average particle diameter of 8 to 20 μm. A molding method,
A high-speed molding method for a T-die cast film, comprising extruding a layer made of the resin composition toward a chill roll surface. 2. The method according to claim 1, wherein the olefin resin is an ethylene polymer. 3. The method according to claim 1, wherein the olefin resin is an ethylene-α-olefin copolymer. 4. The T-die according to claim 1, wherein the olefin resin is an ethylene-α-olefin copolymer produced in the presence of a catalyst containing a transition metal compound having a group having a cyclopentadiene-type anion skeleton. High-speed casting film forming method. 5. The method according to claim 1, wherein the refractive index nD of the fine particles measured at 25 ° C. is in the range of 1.45 to 1.58. 6. The method according to claim 1, wherein the fine particles are organic fine particles. 7. The method according to claim 1, wherein the fine particles are a crosslinked polymethyl methacrylate resin powder. 8. Fine particles having a weight average particle diameter of 8 to 15 μm.
The T-die cast according to any one of claims 1 to 7.
High-speed film forming method .