JPH0726074A - Polyolefin resin film - Google Patents

Abstract

PURPOSE:To provide a polyolefin resin film having excellent transparency and good scratch resistance and slipperiness, little causing contamination of a die during film formation, and having excellent operating efficiency of film formation. CONSTITUTION:A polyolefin resin film is produced from a compsn. wherein 100 pts.wt. polyolefin resin is blended with 0.005-2 pts.wt. particles of a polyacrylic polymer cross-linked with an acrylic and/or methacrylic ester of a trihydric or higher alcohol and the particles have an average particle size of 0.4 to 7mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin resin film which is excellent in transparency, has good slipperiness and scratch resistance, has less die contamination during film formation, and has excellent film forming operability. .

[0002]

2. Description of the Related Art Conventionally, as a method for improving the slipperiness and blocking resistance of a polyolefin resin film, one containing inorganic fine particles (for example, Japanese Examined Patent Publication No. 52-16134).
Japanese Patent Publication No. 42-24523 and Japanese Patent Laid-Open No. 3-9
938) and organic polymer fine particles (JP-A-49-11945 and JP-A-57-645).
No. 22, JP-A-62-39219) and the like are known.

Of these methods, the method of using fine particles of an organic polymer is more useful than the method of using inorganic fine particles because a film having excellent transparency and scratch resistance can be obtained. However, the method using the fine particles of the organic polymer is inferior in heat resistance as compared with the inorganic fine particles, and therefore, for example, the contamination by the deteriorated material at the die outlet during film formation is large, and the number of times of cleaning the die lip needs to be increased. However, there is a problem that the operability of film formation is reduced.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned conventional problems, and its object is to provide excellent transparency, good blocking resistance, scratch resistance, and slipperiness. An object of the present invention is to provide a polyolefin resin film which is less likely to contaminate the die during film formation and has excellent film forming operability.

[0005]

The polyolefin resin film of the present invention comprises acrylic acid and / or methacrylic acid of a polyhydric alcohol having a valence of 3 or more and an average particle diameter of 0.4 to 7 μm with respect to 100 parts by weight of the polyolefin resin. The crosslinked particles of the polyacrylic acid polymer crosslinked with the ester of 0.
A polyolefin resin film comprising a composition in which 005 to 2 parts by weight is blended.

Examples of the polyolefin resin in the present invention include homopolymers or copolymers of propylene, ethylene, butene, 4-methylpentene-1, and the like, or a mixture of these polymers.

The crosslinked particles of the polyacrylic acid type polymer in the present invention must be crosslinked with an ester of acrylic acid and / or methacrylic acid of a polyhydric alcohol having a valence of 3 or more. This is because, in the case of non-crosslinked particles, particles crosslinked with a divalent crosslinking agent such as an ester of acrylic acid and / or methacrylic acid of a dihydric alcohol or divinylbenzene, the heat resistance of the particle is low.
Deteriorated material accumulates at the die exit during film formation, causing streak-like scratches on the film.Therefore, it is necessary to increase the number of times of cleaning the die lip to remove the accumulated deteriorated material. This is because this is not preferable since the operability of film formation will be reduced).

Examples of the polyacrylic acid-based polymer in the present invention include acrylic acid, acrylic acid such as methyl acrylate, ethyl acrylate, and butyl acrylate, or ester derivatives of acrylic acid, methacrylic acid, methyl methacrylate, and meta. Examples of the polymer include 50% by weight or more of methacrylic acid or an ester derivative of methacrylic acid such as butyl acrylate. The acrylic monomer may be used alone or in combination of two or more. Good. Further, as long as it is a small amount, a metal salt of acrylic acid or methacrylic acid, an amide derivative, an ester derivative having a special structure such as a hydroxy ester or dimethylaminoethyl ester may be used.

Other vinyl monomers include styrene,
Examples thereof include styrene such as methylstyrene and α-methylstyrene, or a derivative thereof, and a polymerizable vinyl monomer such as vinyl acetate, vinyl chloride, vinylidene chloride, and acrylonitrile.

Examples of the acrylic acid and / or methacrylic acid ester of a polyhydric alcohol having 3 or more valences in the present invention include, for example, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate and pentaerythritol tetrameta. Examples thereof include, but are not limited to, acrylates and the like. Of these, two or more types may be used in combination. Further, a divalent cross-linking agent such as divinylbenzene or an ester of acrylic acid and / or methacrylic acid of a dihydric alcohol may be used in combination therewith.

The acrylic acid and / or methacrylic acid ester of a polyhydric alcohol having a valence of 3 or more is preferably added so as to be contained in the crosslinked polymer particles in an amount of 0.01 to 0.5% by weight. . If the addition amount is less than 0.01% by weight, the heat resistance of the particles is deteriorated and the film forming operability is deteriorated, which is not preferable. On the other hand, if the amount added exceeds 10% by weight, the heat resistance improving effect is saturated and the particles become hard, so that the scratch resistance of the film deteriorates, which is not preferable.

The method for making the polymer into fine particles is not limited, but a method such as emulsion polymerization or suspension polymerization is used.
A method of directly forming fine particles during polymerization is suitable. When this method is adopted, a means of copolymerizing a polar monomer having a special structure is used in order to impart self-emulsifying property to the polymer, but there is no limitation to use these means, and it is rather preferable. It is an embodiment. The shape of the polymer fine particles is not particularly limited, but is preferably substantially spherical.

The average particle size of the crosslinked particles must be in the range of 0.4 to 7 μm. If the average particle size is less than 0.4 μm, the effect of improving the slipperiness is reduced, and if it exceeds 7 μm, the effect of improving the slipperiness is saturated and the transparency is deteriorated, which is not preferable. The particle size distribution of the crosslinked particles is preferably sharp in order to satisfy transparency, slipperiness and blocking resistance. The average particle size of the polymer fine particles is obtained by taking a photograph with a scanning electron microscope, measuring the Feret diameter in the horizontal direction using an image analyzer, and displaying the average value.

The blending ratio of the polyolefin resin used in the present invention and the crosslinked particles is 0.005 to 2 parts by weight, preferably 0.01 to 1 part by weight, of the crosslinked particles to 100 parts by weight of the polyolefin resin. The amount of crosslinked particles blended is 0.0
If it is less than 05 parts by weight, it is impossible to impart slipperiness and blocking resistance to the film. On the other hand, if it exceeds 2 parts by weight, the slipperiness and blocking resistance are sufficiently provided, but the transparency of the film is remarkably high. It is not preferable because it is inhibited.

The optimum values of the average particle diameter and the blending ratio of the crosslinked particles greatly vary depending on the type of polyolefin resin, the thickness and composition of the film, the presence or absence of stretching, etc. Therefore, it is preferable to arbitrarily set it.

In the present invention, organic or inorganic fine particles other than the crosslinked particles can be used in combination as long as the effects of the present invention are not impaired. Further, in the present invention, a lubricant such as higher fatty acid amide, higher fatty acid ester, wax, and metallic soap may be used in combination to take measures such as improving the slipperiness. Rather, these lubricants should not be used in combination. preferable.

Further, stabilizers, antistatic agents, ultraviolet absorbers, processing aids, which are generally used for polyolefin resins,
There is no restriction on the combined use of plasticizers.

As a method for mixing the above-mentioned crosslinked particles, additives, etc., a mixer such as a V type blender, a screw type blender, a dry blender, a ribbon blender or a Henschel mixer is used to uniformly mix them, and then kneaded into pellets. It is general, but not limited to these.

The crosslinked particles, additives and the like of the present invention can be applied to either an unstretched casting film which is simply extruded or a stretched film which is obtained by stretching the casting film uniaxially or biaxially. Further, it can be applied to both a single layer structure and a multilayer structure composed of two or more layers. In the case of a multi-layer structure, the above-mentioned crosslinked particles are generally added to the surface layer, but the present invention is not limited to this.

Further, in the present invention, it is preferable to improve the adhesiveness of the surface by subjecting the film to surface activation treatment such as corona discharge treatment, plasma treatment and ultraviolet irradiation treatment.

[0021]

EXAMPLES The present invention will be described below based on examples.
The present invention is not limited to these. The measuring method used in the examples is as follows.

(1) Haze value: Measured by Toyo Seiki Haze Destar J according to JIS-K6714.

(2) Coefficient of friction Measured by ASTM-D1894 at 20 ° C. × 65% RH.

(3) Scratch resistance According to JIS-L0823-1971, under a load of 200 gf, with a dyeing fastness friction tester manufactured by Toyo Seiki Co., Ltd., 5
The friction test was performed 0 times, and the degree of increase in the haze value by the friction test was measured by measuring the haze value before and after the test. The smaller the degree of increase, the better the scratch resistance.

(4) Film-forming operation index Using a twin-screw extruder equipped with a nozzle having a diameter of 4 mm, the polymer composition (in the case of a multi-layer film, the polymer composition used for the surface layer) is used at a temperature of 270 ° C. and 12 kg / hr. It was melt-extruded at a discharge amount of 8 hours, and the growth degree (length: mm) of the thermally deteriorated substance deposited on the nozzle surface was displayed. The lower the growth rate, the better the film forming operability.

Example 1 As a base layer (A), a mixture 100 consisting of 90% by weight of a propylene-ethylene copolymer having an ethylene content of 0.5% by weight and 10% by weight of a petroleum resin (trade name Alcon P-115).
A composition obtained by mixing 0.3 part by weight of glycerin resin acid ester and 0.3 part by weight of erucic acid amide with respect to parts by weight was used.

On the other hand, the butene content of the surface layer (B) is 2
Cross-linked acrylic polymer having a spherical and nearly monodisperse particle size distribution with an average particle size of 2.0 μm in 100 parts by weight of a 3% by weight propylene / butene-1 copolymer (melt index 6.0 g / 10 min). Particles [Composition: methyl methacrylate / trimethylolpropane trimethacrylate = 99
/ 1 (weight ratio)] 0.15 part by weight, glycerin fatty acid ester 0.5 part by weight, hydroxystearoamide 0.5
A composition in which parts by weight were mixed and melt-extruded at 180 ° C. was pelletized was used. The composition of the A layer and the B layer was melt extruded from two extruders to obtain a B / A / B three-layer unstretched film. The unstretched film was stretched 4.5 times in the longitudinal direction and 8 times in the transverse direction at 130 ° C., both surfaces were subjected to corona discharge treatment, and a biaxially stretched film having a thickness of 25 μm (thickness ratio 5: 90: 5). Got The characteristic values of the obtained film are shown in Table 1. The film obtained in this example has transparency,
It has excellent slipperiness and scratch resistance, and also has a good operation index during film formation.

Comparative Example 1 A film was obtained in the same manner as in Example 1 except that ethylene glycol dimethacrylate was used instead of trimethylolpropane trimethacrylate as the crosslinking agent for the crosslinked acrylic polymer particles of Example 1. . The properties of the obtained film are shown in Table 1. The film obtained in this comparative example has transparency,
Excellent in slipperiness and scratch resistance, but inferior in operation index during film formation.

Comparative Example 2 In place of the crosslinked acrylic polymer particles of Example 1, crosslinked polystyrene polymer particles [composition: styrene / trimethylolpropane trimethacrylate = 99/1 (weight ratio)] were used. A film was obtained in the same manner as in Example 1. The properties of the obtained film are shown in Table 1. The film obtained in this comparative example has a good operation index and scratch resistance during film formation, but is inferior in transparency.

Comparative Example 3 A film was prepared in the same manner as in Example 1 except that spherical silica having an average particle size of 2.5 μm and having a substantially monodispersed particle size distribution was used in place of the crosslinked acrylic polymer particles of Example 1. Got The properties of the obtained film are shown in Table 1. The film obtained in this comparative example has a good operation index during film formation, but is inferior in transparency and scratch resistance.

Example 2 Cross-linked acrylic polymer having an average particle size of 2.2 μm [composition:
Methyl methacrylate / n-butyl acrylate / styrene / trimethylolpropane trimethacrylate = 79/10/10/1 (weight ratio)] 0.1 wt% of polypropylene having a melt index of 2.5 g / 10 min. Melt extrusion was performed at a temperature of 270 ° C., and rapid cooling was performed with a cooling roll at 30 ° C. to obtain a sheet having a thickness of 0.72 mm. The obtained sheet is stretched at a stretching temperature of 40 ° C. by a factor of 4.5 in the machine direction using the roll peripheral speed difference of the longitudinal stretching machine, and subsequently stretched at a stretching temperature of 155 by a tenter type stretching machine.
It was stretched 8 times in the transverse direction at 0 ° C. Next, heat treatment was performed at 160 ° C. to obtain a biaxially stretched film having a thickness of about 20 μm, and then one surface was subjected to corona treatment. The properties of the obtained film are shown in Table 1. The film obtained in this example is excellent in transparency, slipperiness, and scratch resistance, and also has a good operation index during film formation.

Comparative Example 4 A film was obtained in the same manner as in Example 2 except that ethylene glycol dimethacrylate was used instead of trimethylolpropane trimethacrylate as the crosslinking agent for the crosslinked acrylic polymer particles of Example 2. . The properties of the obtained film are shown in Table 1. The film obtained in this comparative example has transparency,
Film properties such as slipperiness and scratch resistance are good, but the operation index during film formation is poor.

Comparative Example 5 In place of the crosslinked acrylic copolymer particles of Example 2, 0.05% by weight of nylon 6 having an average particle size of 5 μm and amorphous silica having an average particle size of 3 μm were added, respectively. A film was obtained in the same manner as in Example 2. The properties of the obtained film are shown in Table 1. The film obtained in this Comparative Example has good film properties such as transparency, slipperiness, and scratch resistance, but the operation index during film formation is extremely poor.

Example 3 As the base film material (A), an isotactic polybutene-1-ethylene copolymer (ethylene content:
3.5 wt%) 80 wt%, propylene-butene 1 copolymer 10 wt% and propylene-ethylene copolymer 10
A mixed composition of 1% by weight of an ethylene oxide adduct of alkylamine as an antistatic agent was used in a mixed composition of 1% by weight. As the coating film material (B), 50% by weight of propylene-butene 1 copolymer (butene content 12% by weight) and 50% by weight of propylene-ethylene copolymer (ethylene content 4.5% by weight) are used. The mixture was mixed, and 0.2% by weight of cross-linked acrylic polymer particles having the average particle diameter of 3.5 μm (the composition is the same as in Example 1) was used. The materials (A) and (B) are melt-extruded, laminated in a molten state, and then cooled by a cooling roll at 25 ° C., and the thickness ratio of (B) layer / (A) layer / (B) layer is A laminated unstretched film having a thickness of 15/75/15 and a thickness of 720 μm was obtained. The unstretched film was biaxially stretched at 125 ° C. 4.0 times in the longitudinal direction and 4.5 times in the transverse direction, and 4
A 0 μm biaxially stretched film was obtained. The properties of the obtained film are shown in Table 1. The film obtained in this example has excellent film characteristics such as transparency, slipperiness, and scratch resistance, and also has a good operation index during film formation.

Comparative Example 6 A film was obtained in the same manner as in Example 3 except that 0.4% by weight of amorphous silica having an average particle size of 3.5 μm was blended in place of the crosslinked acrylic polymer particles of Example 3. It was The properties of the obtained film are shown in Table 1. The film obtained in this comparative example is inferior in slipperiness.

Comparative Example 7 A film was obtained in the same manner as in Example 1 except that ethylene glycol dimethacrylate was used instead of trimethylolpropane trimethacrylate as the crosslinking agent for the crosslinked acrylic polymer particles of Example 3. It was The properties of the obtained film are shown in Table 1. The film obtained in this comparative example is excellent in transparency, slipperiness, and scratch resistance, but the operation index during film formation is inferior.

Example 4 Propylene-ethylene random copolymer having a melt index of 5 g / 10 min (ethylene content 5% by weight) 10
0 part by weight of 0.25 part by weight of stearic acid amide and 0.3 part by weight of crosslinked acrylic polymer particles having an average particle size of 5 μm (composition is the same as in Example 1) were mixed and melt extruded at a resin temperature of 250 ° C. A cast film having a thickness of 40 μm was obtained by quenching with a cooling roll at 25 ° C. Table 1 shows the properties of the obtained cast film. The film obtained in this example is excellent in transparency, slipperiness, and scratch resistance, and also has a good operation index during film formation.

Comparative Example 8 A cast film was obtained in the same manner as in Example 4, except that 0.3 part by weight of spherical zeolite having an average particle size of 5.0 μm was blended in place of the crosslinked acrylic polymer particles of Example 4. It was
Table 1 shows the properties of the obtained cast film. The film obtained in this comparative example is inferior in transparency and scratch resistance.

Example 5 100 parts by weight of linear low-density polyethylene copolymerized with octene having a melt index of 2.0 g / 10 min, 0.25 part by weight of amide oleate and a crosslinked acrylic polymer having an average particle size of 3.5 μm Example 4 was compounded with 0.40 part by weight of particles.
A cast film having a thickness of 60 μm was obtained by the same method as described above. Table 1 shows the properties of the obtained cast film. The film obtained in this example is excellent in transparency, slipperiness and scratch resistance, and also has a good operation index during film formation.

Comparative Example 9 A cast film was prepared in the same manner as in Example 5 except that 0.40 parts by weight of particles of diatomaceous earth having an average particle size of 3.5 μm were used in place of the crosslinked acrylic polymer particles of Example 5. Got Table 1 shows the properties of the obtained cast film.
The film obtained in this comparative example had a good operation index at the time of film formation, but was poor in all of transparency, slipperiness and scratch resistance.

[0041]

[Table 1]

[0042]

The film of the present invention is composed of a composition in which a specific amount of cross-linked particles of a polyacrylic acid-based polymer cross-linked with a cross-linking agent having a specific structure as described above is blended with a polyolefin resin, so that it is transparent. It has excellent practicability, good slipperiness and scratch resistance, less contamination of the die during film formation, and excellent film forming operability, which is highly practical.

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[Procedure amendment]

[Submission date] July 19, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

It is preferable that the ester of acrylic acid and / or methacrylic acid of a trihydric or higher polyhydric alcohol is added to the crosslinked polymer particles so as to be contained in the range of 0.01 to 10 % by weight. If the addition amount is less than 0.01% by weight, the heat resistance of the particles is deteriorated and the film forming operability is deteriorated, which is not preferable. On the other hand, if the amount added exceeds 10% by weight, the heat resistance improving effect is saturated and the particles become hard, so that the scratch resistance of the film deteriorates, which is not preferable.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

[0022] In accordance with (1) haze JISE-K6714, was measured by Toyo Seiki haze testers J.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Tsutomu Isaka 1-6-6 F202, Komatsukitamachi, Nishinomiya-shi, Hyogo

Claims (1)

[Claims] 1. A polyacrylic acid-based polymer crosslinked with an acrylic acid and / or methacrylic acid ester of a polyhydric alcohol having a valence of 3 or more and having an average particle diameter of 0.4 to 7 μm with respect to 100 parts by weight of a polyolefin resin. Crosslinked particles 0.0
A polyolefin resin film comprising a composition blended in an amount of 05 to 2 parts by weight.