JPH10272677A - Manufacture of propylene resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin film excellent in transparency and sparkling by a method wherein a propylene-ethylene random copolymer, the ethylene content of which is specified and the melt flow rate of which is specified, is extruded from a T-die, the cylinder temperature of which is specified, and then cooled down with a cooling roll, the surface temperature of which is specified. SOLUTION: A propylene-ethylene random copolymer, the ethylene content of which is 3-4 wt.% and the melt flow rate of which is 0.5-5 g/10 min, is extruded from a T-die, the cylinder temperature of which is 190-230 deg.C and then cooled down with a cooling roll, the surface temperature of which is 40 deg.C or lower. Since this propylene-ethylene random copolymer is extruded from the T-die and the quenched with the cooling roll, the obtained propylene resin film has the haze value of at most 3% in terms of 40 μm, gloss value of 80% or more and, in addition, is excellent in transparency and lustering properties and has a favorable sparkling feeling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a propylene-based resin film.

[0002]

2. Description of the Related Art Conventionally, as films used for various kinds of packaging which require transparency, flexibility and the like of textiles, foods, daily necessities, etc., vinylon films added with a plasticizer,
Soft vinyl chloride film is used, but the quality of vinylon film is liable to change due to humidity, and the problem of soft vinyl chloride film is that harmful gas is generated during waste incineration. Therefore, it has been changed to a film made of another resin.

[0003] Therefore, attention has been paid to propylene-based resin films because of their inexpensiveness and the like, and the same transparency and glossiness as vinylon films, soft vinyl chloride, and the like are obtained.
Various attempts have been made to provide flexibility and the like. For example, JP-A-7-290649 discloses a propylene-based resin excellent in transparency and flexibility in which a layer composed of a propylene-based resin is laminated on both sides of a layer composed of a propylene-based resin and a hydrogenated diene-based copolymer. A laminated film is illustrated.

However, although the propylene-based resin laminated film has a high gloss value of 60-degree reflection, it has a problem that the actual appearance of glitter is inferior to a vinylon film or a soft vinyl chloride film.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a propylene-based resin film which is excellent in transparency and has an excellent glittering feeling in actual appearance.

[0006]

According to a first aspect of the present invention, there is provided a method for producing a propylene-based resin film having an ethylene content of 3 to 4% by weight and a melt flow rate (hereinafter, referred to as MFR) of 0.5 to 4%. After extruding a 5 g / 10 minute propylene-ethylene random copolymer from a T-die having a cylinder temperature of 190 to 230 ° C., it is cooled by a cooling roll having a surface temperature of 40 ° C. or less.

The propylene-ethylene random copolymer used in the first aspect of the present invention has an ethylene content of 3%.
４4% by weight, MFR 0.5０．５5 g / 10 min. As the ethylene content decreases, the transparency of the film decreases, and when the ethylene content increases, the film becomes too flexible and difficult to use, and when the MFR is small, the smoothness of the film surface deteriorates and the transparency decreases, When it is larger, the strength of the film is reduced, and the melt viscosity of the resin component is lowered, so that the surface of the film becomes too smooth and the glittering feeling is reduced. The glitter becomes better as the light incident on the film is reflected in a wider angle range. MFR in the present invention
Is a value measured according to JIS K 7210.

In the production method according to the first aspect of the invention, the propylene-ethylene random copolymer is extruded from a T-die and then cooled by a cooling roll. As the transparency decreases, the melt viscosity of the resin component decreases as the transparency increases, and the surface of the film becomes too smooth and the glittering feeling is reduced. Therefore, the temperature is limited to 190 to 230 ° C. Because the transparency of
It is limited to below ℃ As the shape of the cooling roll, any conventionally known shape can be adopted, but a cooling roll having a semi-matte surface is preferable.

The method for producing a propylene-based resin film according to the second aspect of the invention is characterized in that the propylene-ethylene random copolymer used in the first aspect of the invention is 70 to 97.5% by weight and an aromatic vinyl monomer-conjugated. A resin composition comprising a diene copolymer (hereinafter referred to as a diene copolymer) or a hydrogenated product of 2.5 to 30% by weight is extruded from a T-die having a cylinder temperature of 190 to 270 ° C. It is characterized by cooling by a cooling roll having a temperature of 40 ° C. or less.

The diene copolymer used in the second aspect of the present invention may be a random copolymer or a block copolymer. The block copolymer may be an aromatic vinyl monomer polymer block of A, a conjugated diene copolymer. Assuming that the polymer block is B, A (BA) _m or (AB) _n (m and n are natural numbers)
It is represented by Among these, random copolymers and AB
An A-type or AB-type block copolymer is preferable, and a hydrogenated product is preferable in that problems such as discoloration of the film and fish eyes during production are reduced.

The aromatic vinyl monomer includes, for example, styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene and the like, among which styrene and α-methylstyrene are preferred.

As the conjugated diene, for example, 1,3
-Butadiene, isoprene, 2,3-dimethyl-1,3
-Butadiene, 1,3-pentadiene, 2-methyl-
1,3-pentadiene, 1,3-hexadiene, 4,5
-Diethyl-1,3-octadiene, 3-butyl-1,
Examples thereof include 3-octadiene and chloroprene, and among them, 1,3-butadiene and isoprene are preferable.

As the diene-based copolymer, a styrene-butadiene random copolymer or a styrene-isoprene-styrene block copolymer in which isoprene units are mainly composed of 3,4 bonds is preferred. More preferred.

When the copolymerization ratio of the aromatic vinyl monomer in the diene copolymer or its hydrogenated product is reduced, the heat resistance and transparency of the film are reduced, and when the copolymerization ratio is increased, the texture of the film is deteriorated. Since the dispersibility in the resin deteriorates and the transparency of the film deteriorates,
0% by weight is preferable, and more preferably 10 to 30% by weight.
It is.

In the invention according to claim 2, the propylene-ethylene random copolymer and the diene copolymer or a hydrogenated product thereof are mixed with a single-screw extruder, a twin-screw extruder, a Banbury mixer, a kneader mixer, a kneading roll, The resin composition is kneaded with a Brabender or the like, but the compounding amount of the diene-based copolymer or a hydrogenated product thereof does not show a mixing effect of the diene-based copolymer when the amount is small, and the cylinder temperature described below is 230 ° C When the film is manufactured in a state exceeding the limit, the glittering feeling is reduced, and when it is increased, the tensile yield strength of the film is reduced and the strength is weakened, so that wrinkles are easily generated,
Since the cost is also increased, it is limited to 2.5 to 30% by weight.

According to a second aspect of the present invention, the resin composition is extruded from a T-die and then cooled by a cooling roll. For the same reason as described above, the cylinder temperature of the T-die is 190 to 190. It is limited to 270 ° C, and the temperature of the cooling roll is limited to 40 ° C or less.

In the present invention, an inorganic filler such as talc or calcium carbonate, a reinforcing material such as glass fiber or carbon fiber, a heat stabilizer, an antioxidant, a light stabilizer, or the like may be used as long as the transparency of the film is not reduced. Flame retardants, plasticizers, antistatic agents, release agents, foaming agents, lubricants, blocking agents and the like may be added.

Further, if the layer comprising the propylene-ethylene random copolymer according to claim 1 or the propylene-ethylene random copolymer according to claim 2 and a diene copolymer or a hydrogenated product thereof is on the surface, A propylene-based resin film may be used as a multilayer as long as the transparency is not reduced.

The propylene-based resin film obtained by the production method of the present invention has a center line average roughness Ra of 0.5 to 3 μm measured according to JIS B 0601 and an average distance between peaks of a cross-sectional curve. Is 1 to 3 mm, so that the incident light is reflected in a wide angle range, and is excellent in glittering feeling.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

In the examples and comparative examples, hydrogenated products (diene hydrogenated products) of the following propylene resin (PP) and diene copolymer were used. PP1: ethylene content of 3.8% by weight, MFR of 1.
8 g / 10 min propylene-ethylene random copolymer PP2; ethylene content 3% by weight, MFR 0.35
g / 10 min propylene-ethylene random copolymer PP3; ethylene content 2.8% by weight, MFR 8g
Propylene / ethylene random copolymer PP4 / 10 min; propylene homopolymer having an MFR of 2.5 g / 10 min

Diene hydrogenated product 1; manufactured by Nippon Synthetic Rubber Co., Ltd., trade name "Dynalon 1320P" (MFR = 3.5 g / 10
Hydrogenated styrene-butadiene random copolymer having a styrene content of 10% by weight) Diene hydrogenated product 2 (trade name: Hibler HV, manufactured by Kuraray Co., Ltd.)
S-3 "(MFR = 6 g / 10 min, styrene content = 2
0% by weight, hydrogenated product of a styrene-isoprene-styrene block copolymer in which isoprene units are mainly composed of 3,4 bonds.) Diene hydrogenated product 3; trade name "Septon 200" manufactured by Kuraray Co., Ltd.
7 "(MFR = 7 g / 10 min, styrene content = 30% by weight, isoprene unit binding mode is mainly 1,4
Hydrogenated product of styrene-isoprene-styrene block copolymer comprising a bond)

[0023]

EXAMPLES PP1 to 4 and diene hydrogenated product 1 shown in Table 1
After extruding the prescribed blends of Nos. 1 to 3 through a T-die having a prescribed cylinder temperature shown in Table 1, the mixture was cooled with a cooling roll at a temperature of 20 ° C. to obtain a film having a thickness of 50 μm.

The haze and gloss of the obtained film were measured as follows, and the values are shown in Table 1. (Haze) The scattered light transmittance and the total light transmittance were measured according to JIS K 7105, and the haze (%) was calculated by (scattered light transmittance / total light transmittance) × 100. (Gloss) It is a value of specular gloss (%) measured according to JIS Z8741. However, the incident angle of the incident light and the light receiving angle of the reflected light were measured at 60 °.

Further, the obtained film was evaluated for transparency and glittering feeling as follows, and the results are shown in Table 1. (Transparency) ；: A transparent image was clearly seen through the film. Δ: The see-through image through the film was slightly distorted. X: The see-through image through the film was blurred. (Glittering feeling) Light is incident on the film at an angle of 45 °, and ± 10 °, ± 20 °, ±
The reflectance at a light receiving angle of 30 ° was measured by a spectroscopic ellipsometer, and the values are shown in Table 1. The reflectance is the ratio (%) of the reflected light at each light receiving angle when the transmitted light is 100%.
It is.

[0026]

[Table 1]

[0027]

According to the production method of the first aspect of the present invention, a specific propylene-ethylene random copolymer is extruded from a T die and then rapidly cooled by a cooling roll. When the haze value in conversion is 3% or less, and the gloss value is 80% or more, it is excellent in transparency and glossiness, and has a good glittering feeling. In the production method according to the second aspect of the present invention, since the propylene-ethylene random copolymer and the diene-based copolymer are used as the resin components, the width of the cylinder temperature of the T-die for extruding the resin components is reduced. This makes it easier to select the conditions at the time of manufacture.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 9:06) B29K 23:00 B29L 7:00

Claims (2)

[Claims] 1. A propylene-ethylene random copolymer having an ethylene content of 3 to 4% by weight and a melt flow rate of 0.5 to 5 g / 10 min.
A method for producing a propylene-based resin film, comprising extruding from a T-die at 0 ° C. and then cooling with a cooling roll having a surface temperature of 40 ° C. or less. 2. 70 to 97.5% by weight of a propylene-ethylene random copolymer having an ethylene content of 3 to 4% by weight and a melt flow rate of 0.5 to 5 g / 10 minutes, and an aromatic vinyl monomer-conjugate A resin composition comprising 2.5 to 30% by weight of a diene copolymer or a hydrogenated product thereof is extruded from a T-die having a cylinder temperature of 190 to 270 ° C, and then cooled by a cooling roll having a surface temperature of 40 ° C or less. A method for producing a propylene-based resin film.