JP2804365B2 - Resin composition for film and method for producing film using the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a resin composition for a film and a method for producing a film using the same, and particularly has excellent strength, water resistance and moldability when molded. The present invention relates to a resin composition for a film capable of obtaining a film having the same feel and rigidity as paper, and a method for suitably producing a film from the composition.

<Prior Art> Conventionally, paper, polyolefin films such as polyethylene and polypropylene have been used as packaging materials. In particular, in recent years, polyolefins have excellent moldability,
The resulting film is excellent in strength and water resistance,
It is increasingly used as a packaging material.

However, for the packaging of luxury goods, in terms of luxury appearance,
Paper is still used. Therefore, while having excellent strength, water resistance and moldability of the polyolefin film, a paper-like polyolefin film having the same feel and rigidity as paper is required, for example, high-density polyethylene, polypropylene alone, or a composition thereof. In addition, a paper-like polyolefin film obtained by adding an inorganic filler such as calcium carbonate and talc has been proposed (JP-B-46-41463).

<Problems to be solved by the invention> However, the conventional paper-like polyolefin film is
Although it has the same appearance and feel as paper, there is a problem that strength, rigidity and moldability are inferior to polyolefin films.

Therefore, an object of the present invention is to obtain a film having excellent strength, water resistance and moldability inherently possessed by a polyolefin film, inherently having excellent strength, water resistance and moldability, and also having a paper-like feel and rigidity. It is an object of the present invention to provide a resin composition for a film that can be produced, and a method for suitably producing a film from the composition.

<Means for Solving the Problems> In order to solve the above problems, the present invention provides: (A) MFR (190 ° C.): 0.01 to 0.1 g / 10 min., Density: 0.938 to
0.965 g / cm ³ and melt tension: high density polyethylene 35-87 parts by weight is 10g or more, (B) MFR (230 ℃ ):. 0.3~10g / 10min at which propylene polymer 3-25 parts by weight, ( C) 10 to 45 parts by weight of talc, (D) CaO and / or MgO 1 to 10 parts by weight based on 100 parts by weight of the total of (A), (B) and (C), and (E) a surfactant A resin composition for a film containing 0.05 to 1 part by weight based on 100 parts by weight of the total of the components (A), (B) and (C), and having a content ratio of (C) / (B) of 2 to 4 Is provided.

Further, the present invention is a method for producing a film from the resin composition for a film by a blown film molding method as a method for suitably producing a film from the resin composition for a film, wherein a bubble diameter R _A after a frost line is obtained. And the ratio R _A / R _E of the minimum bubble diameter R _E between the die outlet and the frost line is 2 to 6, and the film where the bubble diameter is 0.8 to 1.5 times the die diameter between the die outlet and the frost line. Pickup direction length C
Is adjusted so as to have a length of 2 to 15 times the die diameter _RD , and a film production method is provided.

 Hereinafter, the present invention will be described in detail.

High-density polyethylene which is the component (A) of the resin composition for a film of the present invention (hereinafter simply referred to as “component (A)”)
Has an MFR (190 ° C.) of 0.01 to 0.1 g / 10 min., Preferably 0.0
2 to 0.07 g / 10 min., More preferably 0.02 to 0.05 g / 10 min.,
Density 0.938~0.965g / cm ^3, preferably 0.945~0.960g / c
m ^3, a melt tension is 10g or more, preferably 15g
That's all.

Here, the melt tension is a tension at the time of melting, and is measured under the following conditions using a melt tension tester manufactured by Toyo Seiki Co., Ltd.

Nozzle used: L = 8.000mm, D = 2.095mm Test temperature: 190 ° C Take-off speed: 2m / min. Extrusion speed: 15mm / min. MFR of component (A) (190 ° C) is less than 0.01g / 10min. And the extrudability of the resulting composition decreases, and the MFR (1
(90 ° C.) exceeds 0.1 g / 10 min., It is not possible to produce a film having sufficient strength even if the obtained composition is molded. The MFR was measured according to ASTM 1238.
When the density of the component (A) is less than 0.938, a filter having sufficient rigidity cannot be obtained by molding, and the density is 0.965 g / cm ^3.
If it exceeds 300, a film having sufficient strength cannot be obtained by molding. When the melt tension of the component (A) is 10 g or more, especially 15 g or more, the stability of bubbles at the time of molding the obtained composition into an inflation film becomes good, and the degree of molecular orientation becomes large. A film excellent in strength, tear strength and rigidity can be obtained.

The composition ratio of the component (A) in the composition of the present invention is 35
8787 parts by weight, preferably 45-85 parts by weight. If the blending ratio of the component (A) is less than 35 parts by weight, a film having sufficient strength cannot be obtained by molding, and bubble stability in film forming by the inflation method deteriorates. Therefore, a film having sufficient rigidity cannot be obtained.

The propylene-based polymer (component (B)) as the component (B) of the composition of the present invention is a homopolymer of propylene or other propylene copolymerizable with propylene. And a random copolymer or a block copolymer, preferably a homopolymer of propylene. Examples of the other monomer copolymerizable with propylene include ethylene and butene. The proportion of the comonomer in the copolymer is preferably
Not more than 10 mol%.

The component (B) has an MFR (230 ° C.) of 0.3 to 10 g / 10 min., Preferably 1 to 7 g / 10 min. (B) Component MFR
When (230 ° C.) is less than 0.3 g / 10 min., The dispersibility of the component (B) in the obtained composition is reduced, and the extrudability of the composition is reduced. If the MFR (230 ° C.) exceeds 10 g / 10 min., A film having sufficient strength cannot be obtained. The MFR was measured according to ASTM D1238.

The mixing ratio of the component (B) in the composition of the present invention is 3 to
It is 25 parts by weight, preferably 5 to 25 parts by weight. If the component (B) is less than 3 parts by weight, a film having sufficient rigidity cannot be obtained by molding, and if it exceeds 25 parts by weight, a film having sufficient strength cannot be obtained.

The talc (hereinafter simply referred to as “component (C)”) as the component (C) of the composition of the present invention is usually used in such a resin composition and is not particularly limited. ,
Those having an average particle size of 1.5 to 4.5 μm, an oil absorption of 38 to 52 cc / 100 g, and a moisture content of 0.3% or less are preferred.

The mixing ratio of the component (C) in the composition of the present invention is 10 to
It is 45 parts by weight, preferably 10 to 40 parts by weight. If the compounding ratio of the component (C) is less than 10 parts by weight, a film having good paper-like appearance and sufficient rigidity cannot be obtained by molding, and
If the amount is more than 10 parts by weight, the moldability of the obtained composition is reduced.
In addition, a film having sufficient strength cannot be obtained by molding.

In the composition of the present invention, the component (C) / (B)
The content ratio of the components is adjusted to be 2 to 4, preferably 2.5 to 3.5. When the content ratio of the component (C) / the component (B) is less than 2, a film having a good paper-like appearance cannot be obtained even when the obtained composition is molded. Also 4
If it exceeds, a film excellent in impact strength and tear strength cannot be obtained even when the obtained composition is molded.

CaO and / or MgO (hereinafter simply abbreviated to “(D) component”) as the (D) component of the composition of the present invention are not particularly limited as long as they are suitably blended in the resin composition.

The mixing ratio of the component (D) in the composition of the present invention is 1 to 10 parts by weight, preferably 1.5 to 8 parts by weight based on 100 parts by weight of the total of the components (A), (B) and (C). is there. When the blending ratio of the component (D) is less than 1 part by weight based on 100 parts by weight of the total of the components (A), (B) and (C), the resulting composition is used to form a film. Poor formability causes holes in the film due to foaming. Further, even if it is added in a proportion exceeding 10 parts by weight, no further effect can be obtained.

The surfactant which is the component (E) of the composition of the present invention (hereinafter simply referred to as “component (E)”) may be any of a nonionic, anionic, cationic or amphoteric surfactant. , Is not particularly limited.

Examples of the nonionic surfactant include N, N-bis (2-hydroxyethyl) alkylamine, fatty acid ester of polyoxyethylene alkylamine, glycerin fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, and polyoxyethylene. Ethylene aliphatic alcohol ethers, polyoxyethylene alkyl phenyl ethers, polyethylene glycol fatty acid esters and the like can be mentioned.

Examples of the anionic surfactant include an alkyl sulfonate, an alkylbenzene sulfonate, an alkyl sulfate, and an alkyl phosphate.

Examples of the cationic surfactant include a tetraalkylammonium salt and a trialkylbenzylammonium salt.

Examples of the amphoteric surfactant include an alkyl betaine type and an imidazoline type.

In the present invention, as the component (E), the above-mentioned surfactants may be used alone or in combination of two or more.

Among these surfactants, the nonionic glycerin fatty acid ester improves the dispersibility of the components (C) and (D), and other additives, if necessary, in the composition. It is particularly preferable because the effect of improving various physical properties such as moldability of the obtained composition is great.

The proportion of the component (E) in the composition of the present invention is 0.05 to 1 part by weight, preferably 0.1 to 0.8 part by weight, based on 100 parts by weight of the total of the components (A), (B) and (C). is there. When the compounding ratio of the component (E) is less than 0.05 parts by weight based on 100 parts by weight of the total of the components (A), (B) and (C), the components (C), (D) and Dispersibility in a composition such as an agent cannot be improved.
On the other hand, when the amount exceeds 1 part by weight, the component (E) bleeds out on the surface of the obtained film, which causes deterioration of the appearance of the film.

Further, the composition of the present invention includes the above (A), (B),
In addition to the components (C), (D) and (E), various additives usually used in this type of resin composition, for example, phenol-based and phosphorus-based heat stabilizers; inorganic pigments such as titanium oxide;
Alternatively, a colorant such as an organic pigment may be appropriately added alone or in combination of two or more.

The resin composition for a film of the present invention comprises the above (A),
Predetermined amounts of the components (B), (C), (D) and (E) and, if necessary, other optional components are simultaneously mixed, and the resulting mixture is biaxially extruded at, for example, 180 to 250 ° C. May be produced by melt-kneading using a mixer, a Banbury mixer or the like, or the components (C), (D) and (E) may be mixed with the component (B).
Alternatively, a mixture (F) is prepared by previously mixing the component (A) with the component (A), and the mixture (F) is mixed with the component (A) or the component (B) to form a film during film formation. It may be.

The resin composition for a film of the present invention can be applied to any film forming method such as an inflation film forming method and a film forming method using a T-die, and is particularly suitable for film production by an inflation film forming method.

As a method for suitably producing a film by this inflation film molding method, the present invention relates to a method for producing a film by an inflation film molding method, wherein R _A : bubble diameter after the frost line, R _E : frost from the die outlet. The minimum bubble diameter between the lines, C: the length in the film taking-off direction where the bubble diameter is 0.8 to 1.5 times the die diameter between the die outlet and the frost line, and R _D : the value of the die diameter is calculated by the following formula. The molding is performed by adjusting so as to satisfy the following.

This method is performed using, for example, an inflation film forming apparatus as shown in FIG. In the figure, a blown film forming apparatus 1 includes a hopper 2 for providing a resin composition, an extruder 3 for melting and homogenizing a supplied resin composition, and extruding a molten resin composition into a cylindrical shape. A cylindrical die 4 for molding; an air cooling ring 5 for blowing air to the extruded resin composition to cool the resin composition; a take-off machine 6 for drawing a film obtained by cooling; and a winding device for winding the obtained film. It has a winding machine 7.

In this apparatus, the resin composition is supplied from the hopper 2 to the extruder 3 and melted and homogenized by the heat from the cylinder wall of the extruder 3 and the frictional heat of the screw. As shown in FIG. 2, which is an enlarged view of the portion, the bubble is formed from the cylindrical die 4 to form a bubble 8 and is extruded from a narrow slit, and at the same time, is expanded by air blown through the inside of the die. On the other hand, the air 9 ejected from the air cooling ring 5 on the outside
The bubble 10 is formed by the secondary shaping which is cooled and solidified by the cooling. The film 11 obtained by cooling is guided to a guide plate 12, taken up by a take-up machine 6, and further taken up by a take-up machine 7.
Will be taken over.

In the above blown film molding, as shown in FIG. 2, the present invention cools and whitens the resin composition extruded from the cylindrical die 4, that is, the bubble after the frost line (whitening point) 13 10 diameter R _A
And the ratio R _A / R _E of the minimum bubble diameter R _E of the bubble 8 between the outlet 14 of the die 4 and the frost line 13 is 2 to 6, preferably 3 to 5, and the frost from the outlet 14 of the die. The diameter of the bubble 8 between the lines 13 is the diameter of the die
Length C in the film take-off direction of the portion 0.8 to 1.5 times R _D
However, the method is characterized in that the molding is performed by adjusting the die diameter _RD to 2 to 15 times, preferably 5 to 10 times.

That is, the molding is performed by adjusting the heating temperature in the extruder, the film take-up speed, and the air volume of the air cooling ring 5 so as to satisfy the following expression.

When R _A / R _E of the formula (1) is less than 2, the resulting composition cannot be molded to obtain a film having sufficient impact strength and tear strength, and when it exceeds 6, it is obtained. Even when the composition is molded, bubble stability during film formation deteriorates, and productivity decreases.

If the C / _RD of the formula (2) is less than 2, the resulting composition cannot be molded to obtain a film having sufficient impact strength and tear strength. Bubble stability deteriorates and productivity decreases.

The heating temperature in the extruder is usually about 180 to 230 ° C, preferably about 190 to 220 ° C.

The take-up speed of the film is usually about 10 to 70 m / min.

The extruder, die, take-up machine, winder, etc. used are
It may be a regular one and is not particularly limited.

Although the method of the present invention has been described above with respect to the film forming by the upward take-off method shown in FIG. 1, the present invention is not limited to the method shown in FIG. It goes without saying that the present invention is similarly applied to any film forming by the above method.

The composition of the present invention as described above is molded and has an appearance, a texture,
A film having the same appearance and feel as paper in terms of bendability, and having excellent strength can be obtained, and the method of the present invention can produce a film from the composition as high as a normal polyolefin film. Can be obtained with productivity.

Since the film obtained by the above composition and method of the present invention has excellent characteristics as described above, it is suitably used as a printing paper for shopping bags, maps, posters, etc. taking advantage of its good weather resistance. Can be

<Example> Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples of the present invention.

(Examples 1 to 4, Comparative Examples 1 to 8) In each example, each component was charged into a Henschel mixer having an internal volume of 20 and mixed for 3 minutes according to the formulation shown in Table 1, and then mixed with CIM65φ (manufactured by Nippon Steel Works, Ltd.). After melt-kneading at 180 to 200 ° C using a twin screw), pellets were obtained with a 65φ short screw extruder. The talc used had an average particle size of 3.0μ.
m, an oil absorption of 41 cc / 100 g and a water content of 0.1%, and monoglyceride stearate was used as a surfactant. The melt tension of the component (A) used was measured under the following conditions using a melt tension tester manufactured by Toyo Seiki Co., Ltd.

Nozzle used: L = 8.000 mm, D = 2.095 mm Test temperature: 190 ° C Take-off speed: 2 m / min. Extrusion speed: 15 mm / min. The obtained pellets were blown into a 50φ blown film molding machine (extruder: Modern Machinery Co., Ltd.) 50mm, screw, screw length / screw diameter ratio: 24, compression ratio: 2.0, die diameter _RD : 100mmφ, and lip width: 1mm) under the following molding conditions and molding temperature
A film having a thickness of 40 μm was produced at a temperature of 200 ° C. and a take-off speed of 20 m / min.

Film forming conditions Examples 1-4, Comparative Examples 1, 2, 4-7 R _A / R _E = 3.0, C = 1000 mm, C / R _D = 10 Comparative Example 3 R _A / R _E = 1.5, C = 100 mm, C / R _D = 1 The film impact strength and tear strength by Elmendorf method of the obtained film were measured by ASTM D3420 and JIS, respectively.
It was measured in accordance with Z1702, and its feel, rigidity and formability during film formation were evaluated according to the following criteria.

For comparison, the kraft paper was similarly measured for film impact strength and Elmen tear strength, and its feel, rigidity and moldability were evaluated (Comparative Example 8). Table 1 shows the results.

Feeling and stiffness…: Has paper-like feeling, stiffness and fold retention.

Δ: Intermediate feel and rigidity between paper and polyolefin film.

 ×: Does not have paper-like feel and rigidity.

Moldability…: Same moldability as ordinary polyolefin film.

Δ: Molding is possible, but slightly inferior to ordinary polyolefin films.

X: During molding, the bubble was shaken or cut, resulting in poor bubble stability.

(Examples 5 to 6, Comparative Examples 9 to 11) According to the blending method shown in Table 2, pellets were obtained in the same manner as in Example 1. Using the same blown film molding machine, a film was produced under the following molding conditions. The talc used was the same as in Example 1.

Film forming conditions Example 5 and Comparative Examples 9 to 14 Same as Example 1.

Comparative Example 15 R _A / R _E = 1.5, C = 1000 mm, C / R _D = 10 Comparative Example 16 R _A / R _E = 3.0, C = 100 mm, C / R _D = 1 Example 6 R _A / R _E = 3.0, C = 500 mm, C / R _D = 5 Comparative Example 17 R _A / R _E = 3.0, C = 2000 mm, C / R _D = 20 Example 7 R _A / R _E = 5.0, C = 1000 mm, C / R _D = 10 The physical properties of the obtained film were measured in the same manner as in Example 1.
Table 2 shows the results.

<Effect of the Invention> The resin composition for a film of the present invention exhibits excellent moldability at the time of forming a film, and the obtained filter has excellent strength and water resistance, and has a paper-like feel, rigidity and fold retention. It has the property.

Further, the method of the present invention is suitable as a method for producing a film from the film-like resin composition.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating the method of the present invention for producing a film from the resin composition for a film of the present invention by a blown film molding method, and FIG. 2 is an enlarged schematic diagram illustrating the features of the method. . DESCRIPTION OF REFERENCE NUMERALS 1 ... blown film forming apparatus, 2 ... hopper, 3 ... extruder, 4 ... cylindrical die, 5 ... air cooling ring, 6 ... take-up machine, 7 ... take-up machine, 11 …… Film, 12 …… Guide plate, 13 …… Frost line

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ identification code FI C08L 23:10) (58) Investigated field (Int.Cl. ⁶ , DB name) C08L 23/00-23/36

Claims (2)

(57) [Claims] (A) MFR (190 ° C.): 0.01 to 0.1 g / 10 min.
Density: 0.938 to 0.965 g / cm ³ and melt tension: 35 to 87 parts by weight of high-density polyethylene having a weight of 10 g or more; (B) MFR (230 ° C.): propylene-based polymer having a 0.3 to 10 g / 10 min. (C) 10 to 45 parts by weight of (C) talc, (D) CaO and / or MgO 1 to 10 parts by weight based on 100 parts by weight of the total of (A), (B) and (C), and (E) ) Surfactant A film containing 0.05 to 1 part by weight based on 100 parts by weight of the total of the components (A), (B) and (C), and the content ratio of (C) / (B) is 2 to 4 Resin composition. 2. _A method for producing a film from the resin composition for a film by a blown film molding method according to claim 1, wherein R _{A is} a bubble diameter after a frost line, and R _{E is} a distance between a die outlet and a frost line. The minimum bubble diameter, C: the length in the film taking-off direction where the bubble diameter is 0.8 to 1.5 times the die diameter between the die outlet and the frost line, and R _D : the value of the die diameter satisfies the following formula. A method for producing a film, characterized in that the film is adjusted and formed.