JP3428462B2 - Manufacturing method of polyolefin resin film - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to transparency, slipperiness,
Polyolefin with excellent blocking resistance and scratch resistance
The fin resin film, generated during film die lip "eye mucus" and generates less resin droplets called relates excellent production method membrane productivity.

[0002]

2. Description of the Related Art Conventionally, as a method for improving the slipperiness and blocking resistance of a polyolefin resin film, a method of adding fine particles of inorganic fine particles such as silica and talc to a resin, or a method of adding organic polymer crosslinked particles It has been known. Among these methods, the method of adding the organic polymer crosslinked particles has a higher transparency than the method of adding the inorganic fine particles,
A polyolefin resin film having excellent scratch resistance can be obtained (JP-A-5-214120). However, the method of adding organic polymer cross-linked particles has a higher occurrence rate of "eye grease" at the time of film formation than the method of adding inorganic fine particles, and if the "eye grease" adheres to the film, Since scratches are formed, it is necessary to remove them, and the number of times of cleaning the die slip increases, which causes a problem that the film productivity decreases.

[0003]

[0008] The present invention, transparency, slip properties, blocking resistance, excellent scratch resistance poly
An object of the present invention is to provide a manufacturing method of an olefin resin film , which has less contamination of a die called "skin oil" at the time of film formation and has excellent film productivity.

[0004]

Means for Solving the Problems As a result of various studies, the present inventors have found that, relative to 100 parts by weight of a polyolefin resin, 0.03 to 3 parts by weight of porous spherical organic polymer crosslinked particles having an average particle diameter of 2 to 15 μm are added. Press the blended polyolefin resin
The present invention has been completed by finding out that all the above-mentioned problems can be solved by molding . That is, the present invention relates to (1) a polyolefin resin film which is formed by extruding a polyolefin resin containing 0.01 to 1% by weight of porous spherical organic polymer crosslinked particles having an average particle diameter of 2 to 15 μm .
Manufacturing method , (2) Porous spherical organic polymer crosslinked particles have a porosity of 5 to 5
0%, the method for producing a polyolefin resin film according to (1), wherein the pore diameter is 5 to 5,000 nm.
And (3) the porous spherical organic polymer cross-linked particles contain 50 to 99.9% by weight of alkyl (meth) acrylate and 0.1 to 30 of a polyfunctional monomer having two or more vinyl groups in the molecule.
Production of the polyolefin resin film according to (1) above, which is obtained by copolymerizing a monomer mixture consisting of 0 to 49.9% by weight of other copolymerizable monomer in the presence of a porosifying agent. Is the law .

[0005]

Polyolefin resins formulating porous spherical organic polymer crosslinkable particles in DETAILED DESCRIPTION OF THE INVENTION The present invention is, for example, ethylene, propylene, butene, carbon number of 4-methylpentene-1, etc. backbone 2 Examples thereof include homopolymers or copolymers of olefinic hydrocarbons of to 6 or mixtures of these polymers. The porous spherical organic polymer crosslinked particles in the present invention means 50 to 99.9% by weight of alkyl (meth) acrylate, 0.1 to 30% by weight of a polyfunctional monomer having two or more vinyl groups in the molecule, and It is obtained by copolymerizing a monomer mixture consisting of 0 to 49.9% by weight of another copolymerizable monomer in the presence of a porosifying agent. Examples of the alkyl (meth) acrylate include methyl (meth) acrylate and ethyl (meth)
Examples thereof include acrylate, propyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isononyl (meth) acrylate, each of which has an alkyl group having 1 to 10 carbon atoms.

As the polyfunctional monomer having two or more vinyl groups in the molecule, aromatic divinyl monomers such as divinylbenzene, ethylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate,
Hexanediol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate and other alkane polyols Poly (meth) acrylate, allyl (meth) acrylate, diallyl itaconate, etc. Examples thereof include monomers having a vinyl group, urethane di (meth) acrylate, and epoxy (meth) acrylate. As other copolymerizable monomers, styrene, vinyltoluene, aromatic vinyl such as α-methylstyrene,
Examples thereof include vinylidene cyanide such as aromatic vinylidene, acrylonitrile, methacrylonitrile, vinylidene cyanide, urethane (meth) acrylate and the like. It is also possible to copolymerize a monomer having a functional group. For example, a monomer having an epoxy group such as glycidyl methacrylate, a monomer having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid and itaconic acid, a monomer having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, diethylaminoethyl (meth ) Examples include monomers having an amino group such as acrylate. As the method for synthesizing the crosslinked porous spherical organic polymer particles in the present invention, methods such as emulsion polymerization, suspension polymerization and dispersion polymerization are used, and preferably suspension polymerization is performed. The suspension polymerization is carried out using the above-mentioned monomer mixture, dispersion stabilizer, surfactant, oil-soluble radical polymerization initiator, porosifying agent and the like. The oil-soluble radical polymerization initiator and the porosifying agent are preferably dissolved or dispersed in the above-mentioned monomer mixture in advance.

As the dispersion stabilizer, gelatin, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, polyethylene glycol, polyacrylamide, polyacrylic acid, polyacrylic acid salt, sodium alginate, partially saponified polyvinyl alcohol, etc. Polymers, inorganic substances such as tricalcium phosphate, titanium oxide, calcium carbonate and silicon dioxide are used. Further, these dispersion stabilizers may be used alone or in combination of two or more. As the surfactant, anionic surfactants such as sodium dodecylbenzenesulfonate, sodium dialkylsulfosuccinate, sodium lauryl sulfate, etc., and nonionic surfactants such as polyethylene glycol nonylphenyl ether, etc. are used. Further, these surfactants can be used alone or in combination of two or more. Examples of the oil-soluble radical polymerization initiator include benzoyl peroxide, o
-Methoxybenzoyl peroxide, o-chlorobenzoyl peroxide, lauroyl peroxide, cumene hydroperoxide and other organic peroxides, 2,
Azo compounds such as 2'-azobisisobutyronitrile and 2,2'-azobis-2,4-dimethylvaleronitrile are used. Further, these oil-soluble radical polymerization initiators can be used alone or in combination of two or more.

The porosity-imparting agent is a substance which makes the organic polymer cross-linked particles porous, and there are several kinds. One of them is, for example, a solvent such as toluene, isooctane, and methyl isobutyl ketone, which is soluble in the above-mentioned monomer mixture but not in the polymer after the polymerization. In this case, the amount of the solvent used is 20 to 20 with respect to 100 parts by weight of the monomer mixture.
The amount of the porosifying agent used is about 0 part by weight, and the porosifying agent used is removed in the step of drying the particles, and the portions where the solvent is removed become pores. Further, as another porosifying agent, an inorganic substance such as calcium carbonate, tricalcium phosphate, etc., which is dissolved by a strong acid, can be used. In this case, the amount of the inorganic material used is 20 to 20 with respect to 100 parts by weight of the monomer mixture.
The porosifying agent used is about 0 parts by weight and is removed by dissolving it with a strong acid in the step of purifying the particles after the polymerization, and the dissolved and removed portion becomes pores. As another porosifying agent, a linear polymer, such as alkyl poly (meth) acrylate, which is soluble in the above-mentioned monomer mixture, is used. In this case, the amount of the linear polymer used is about 1 to 10 parts by weight based on 100 parts by weight of the monomer mixture, and the linear polymer which has been dissolved in the course of proceeding the polymerization of the monomer mixture described above is used. The polymer undergoes phase separation and the particles become porous. The type of linear polymer used is not particularly limited, but the shape and size of the pores differ depending on the type of polymer. The porosifying agent for obtaining these porous spherical polymer crosslinked particles may be used alone or in combination of two or more kinds.

The average particle diameter of the porous spherical organic polymer crosslinked particles used in the present invention is in the range of 2 to 15 μm. When the average particle diameter is smaller than the above range, the effect of blocking resistance becomes small, a large addition amount is required, and the transparency of the polyolefin resin film is impaired. On the other hand, when the average particle diameter is larger than the above range, the film has a rough feeling and the transparency is also impaired. The “spherical” in the particles of the present invention does not necessarily have to be a true spherical shape and means a particle shape without large protrusions. The porous spherical organic polymer cross-linked particles obtained by the above method preferably have a porosity of 5 to 50% and a diameter of pores of 5 to 5,000 nm. The effect cannot be obtained, and the generation of "eyelids" cannot be reduced. The mixing ratio of the porous spherical organic polymer cross-linked particles obtained by the above method to the polyolefin resin is usually 0.1 with respect to 100 parts by weight of the polyolefin resin.
It is 0.1 to 3 parts by weight, preferably 0.1 to 1 part by weight.
If the blending ratio is less than the above range, sufficient slipperiness and blocking resistance cannot be imparted. On the other hand, when the blending ratio is larger than the above range, sufficient slipperiness and blocking resistance are imparted, but transparency is significantly impaired.

The average particle diameter of the porous spherical organic polymer crosslinked particles and the optimum value of the resin blending vary greatly depending on the type of polyolefin resin, the thickness and configuration of the polyolefin resin film, the presence / absence of stretching, etc. It may be appropriately set within the above range according to the characteristics of the polyolefin resin film. In the present invention, additives other than the porous spherical organic polymer crosslinked particles may be blended as long as the effects of the present invention are not impaired. Examples of the additives include various stabilizers such as antioxidants and ultraviolet absorbers, lubricants, antistatic agents, and inorganic fillers in some cases. The method for mixing the above-mentioned porous spherical organic polymer crosslinked particles and additives is not particularly limited, but mixed with a Hensyl mixer, a tumbler, etc., and melt-kneaded with a single-screw or twin-screw extruder. Generally, it is pelletized. The present invention can be applied to both an unstretched casting film that is simply extruded and a stretched film that is obtained by stretching the casting film in a uniaxial or biaxial direction. Further, it can be applied to both a single layer structure and a multilayer structure. In the case of a multilayer structure, the porous spherical organic polymer crosslinked particles described above,
It is generally added to the surface layer, but not limited to this.

[0011]

EXAMPLES The present invention will be described in more detail based on the following Reference Examples, Examples and Comparative Examples, but the present invention is not limited thereto. Reference Example 1 Preparation of Porous Spherical Organic Polymer Crosslinked Particles Polyvinyl alcohol (Kuraray Poval 2
05, manufactured by Kuraray Co., Ltd.) To an aqueous solution in which 5 g was dissolved, a mixed solution consisting of 190 g of methyl methacrylate, 10 g of trimethylolpropane trimethacrylate, 1 g of lauroyl peroxide and 100 g of methyl isobutyl ketone was added, and this was mixed using a homomixer. The mixture was stirred to prepare a dispersion liquid of the monomer mixed liquid. At this time, the rotation speed of the stirring blade of the homomixer was 5,000 rpm and 3,200 rp, respectively.
The mixture was stirred at m and 2,100 rpm to prepare three kinds of dispersion solutions having different particle sizes. Each of the dispersion solutions was transferred to a four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen blowing port, heated to 60 ° C. while stirring under a nitrogen stream, and reacted for 3 hours as it was. The obtained suspension was cooled to room temperature, filtered and washed with water, and the filter cake was dried at 110 ° C. for 24 hours to obtain porous spherical organic polymer crosslinked particles. The obtained porous spherical organic polymer cross-linked particles were A-1 and A-, respectively, in order of decreasing particle size.
2 and A-3. The properties of the particles are shown in [Table 1].

Reference Example 2 Preparation of Non-porous Spherical Organic Polymer Crosslinked Particles Polyvinyl alcohol (Kuraray Poval 2
05 (manufactured by Kuraray Co., Ltd.), 190 g of methyl methacrylate, 10 g of trimethylolpropane trimethacrylate, and 1 lauroyl peroxide were dissolved in an aqueous solution.
g mixture was added. This was stirred using a homomixer to prepare a dispersion liquid of a monomer mixed liquid. At this time, the stirring intensity of the homomixer was changed in three steps as in Reference Example 1 to prepare three types of dispersion solutions having different particle sizes. Each of the dispersed solutions was transferred to a four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen blowing port, heated to 60 ° C. while stirring under a nitrogen stream, and reacted for 3 hours as it was. The obtained suspension was cooled to room temperature, filtered and washed with water, and the filter cake was dried at 110 ° C. for 24 hours to obtain non-porous spherical organic polymer crosslinked particles. The obtained non-porous spherical organic polymer cross-linked particles were designated as B-1, B-2, and B-3 in order of decreasing particle size. The properties are shown in [Table 1].

The various physical properties of the particles obtained in each of the reference examples were tested by the following methods. [Average particle size (μm)] Coulter Multisider II
(Manufactured by Coulter Co., Ltd.) and the value of the arithmetic diameter of the weight distribution was adopted. [Porosity (%)] The porosity was determined by the mercury penetration method. [Pore diameter (nm)] The pore size was confirmed by SEM.

[0014]

[Table 1]

Example 1 Polypropylene containing 0.3% by weight of porous spherical organic polymer crosslinked particles A-1 was extruded from a T die at a resin temperature of 270 ° C. to obtain a film having a thickness of 30 μm. The obtained film was a film having excellent transparency, slipperiness, and scratch resistance, and the occurrence of "skin oil" during film formation was small. The properties of the obtained film are shown in [Table 2]. Comparative Example 1 A film was obtained in the same manner as in Example 1 except that the non-porous spherical organic polymer crosslinked particles B-1 were used instead of the porous spherical organic polymer crosslinked particles A-1. The obtained film was a film excellent in transparency, slipperiness, and scratch resistance, but "eye grease" was often generated during film formation. The properties of the obtained film are shown in [Table 2]. Comparative Example 2 A film was obtained in the same manner as in Example 1 except that the porous spherical organic polymer crosslinked particles A-1 were replaced with porous spherical organic polymer crosslinked particles A-3 having a large average particle diameter. It was The obtained film was excellent in slipperiness and scratch resistance, but was inferior in transparency. However, the occurrence of "eye grease" during film formation was small. The properties of the obtained film are shown in [Table 2]. Comparative Example 3 A film was obtained in the same manner as in Example 1 except that fine powder silica (average particle diameter 2.5 μm) was used instead of the porous spherical organic polymer crosslinked particles A-1. The obtained film was inferior in transparency, slipperiness and scratch resistance,
There was little occurrence of "eyelids" during film formation. The properties of the obtained film are shown in [Table 2].

Example 2 Polyethylene containing 0.3% by weight of porous spherical organic polymer crosslinked particles A-2 was extruded from a T die at a resin temperature of 240 ° C. to obtain a film having a thickness of 20 μm. The obtained film was a film having excellent transparency, slipperiness, and scratch resistance, and the occurrence of "skin oil" during film formation was small.
The properties of the obtained film are shown in [Table 2]. Comparative Example 4 A film was obtained in the same manner as in Example 2 except that the non-porous spherical organic polymer crosslinked particles B-2 were used in place of the porous spherical organic polymer crosslinked particles A-2. The obtained film was a film excellent in transparency, slipperiness, and scratch resistance, but "eye grease" was often generated during film formation. The properties of the obtained film are shown in [Table 2]. Comparative Example 5 A film was prepared in the same manner as in Example 2 except that the non-porous spherical organic polymer crosslinked particles B-3 having a large average particle diameter were used instead of the porous spherical organic polymer crosslinked particles A-2. Obtained.
The obtained film was excellent in slipperiness and scratch resistance, but was inferior in transparency. However, there were many occurrences of "eyelids" during film formation. The properties of the obtained film are shown in [Table 2].

Comparative Example 6 A film was obtained in the same manner as in Example 2 except that fine spherical silica (average particle diameter 2.5 μm) was used in place of the porous spherical organic polymer crosslinked particles A-2. . The obtained film was inferior in transparency, slipperiness and scratch resistance,
The generation of "eye grease" during film formation was small. The properties of the obtained film are shown in [Table 2]. The test of each film obtained in the above-mentioned Examples and Comparative Examples was conducted by the following method. [Haze (%)] Measured by Toyo Seiki Haze Tester J according to JIS-K6714. [Scratch resistance] Measured according to JIS-LO823-1971. That is, 50 times friction test was performed under a load of 200 gf using a dyeing fastness friction tester manufactured by Toyo Seiki.
The haze value was measured before and after the test to measure the degree of haze increase. [Degree of generation of grease] Twin-screw extruder (Ikegai Iron & Steel Co., Ltd.)
Manufactured by: PCM-30), the polyolefin resin, particles and additives are melt-kneaded, and the discharge rate of 4 kg / hr is 1
The amount of "grease" generated in the die when extruding for time and pelletizing, and the pellets in a T-die (made by Chugai Trading:
EXTRUDER (Type: MK-B4)) was used to visually observe the amount of "eyelids" generated when forming a film, and the comprehensive evaluation was displayed as five levels of "eyelids" generation (the higher the number, the higher the number). Indicates that a large amount of "eye oil" is generated).

[0018]

[Table 2]

[0019]

The polyolefin resin film containing the porous spherical organic polymer crosslinked particles obtained by the method of the present invention is excellent in transparency, slipperiness, blocking resistance and scratch resistance, and is suitable for die slip during film formation. The production of resin drops, which are often referred to as "eye grease," is less likely to occur, and the productivity is improved. In addition, since particles do not fall out of the film during film stretching, the generation of voids is suppressed.

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Claims (3)

(57) [Claims] 1. A method for producing a polyolefin resin film, which comprises extruding a polyolefin resin containing 0.03 to 3% by weight of porous spherical organic polymer crosslinked particles having an average particle diameter of 2 to 15 μm. 2. The production of a polyolefin resin film according to claim 1, wherein the porous spherical organic polymer crosslinked particles have a porosity of 5 to 50% and a pore diameter of 5 to 5,000 nm.
Law . 3. A polyfunctional monomer having a porous spherical organic polymer crosslinked particle, the polyfunctional monomer having an alkyl (meth) acrylate content of 50 to 99.9% by weight and having two or more vinyl groups in the molecule.
-30% by weight and other copolymerizable monomers 0-49.
The method for producing a polyolefin resin film according to claim 1, which is obtained by copolymerizing a mixture of 9% by weight of a monomer in the presence of a porosifying agent.