KR102433715B1 - Process for production of thermoplastic resin film - Google Patents

Abstract

assignment
A method for producing a thermoplastic resin film having high thickness precision is provided.
solution
The method for producing a thermoplastic resin film of the present invention is a method for producing a thermoplastic resin film in which a sheet-like molten thermoplastic resin material (3) extruded from a die (2) is sandwiched between two cooling rolls (4, 5), On the outer peripheral surface of both ends of at least one of the two cooling rolls 4 and 5, step portions 10 having an outer diameter smaller than the outer diameter of the central portion of the roll are formed circumferentially, respectively, the molten thermoplastic resin When the material (3) is sandwiched between the two cooling rolls (4, 5), it is also sandwiched between the step portion (10) and the other cooling roll, and the molten thermoplastic resin material (3) is inserted into the step portion (10) The linear pressure received between the and the other cooling roll is substantially 0 kgf/cm.

Description

Method for producing a thermoplastic resin film {PROCESS FOR PRODUCTION OF THERMOPLASTIC RESIN FILM}

The present invention relates to a method for producing a thermoplastic resin film.

In flat panel displays, such as a liquid crystal display device and a plasma display, the film which consists of a thermoplastic resin is used as an optical film.

For example, a polarizing plate used in a liquid crystal panel assembled in a liquid crystal display device is usually on at least one surface of a polyvinyl alcohol-based polarizing film, as a protective film, excellent in transparency and low optical anisotropy triacetyl An optical film made of cellulose is used in a laminated state.

Triacetyl cellulose film is usually produced by the casting method, has excellent thickness precision, and is suitable for use as an optical film, but it is necessary to use an organic solvent such as methylene chloride or methanol for production of the film There is a large environmental load. Then, it is excellent in thickness precision and the optical film with a small environmental load is desired.

As a manufacturing method of a thermoplastic resin film, there exist an inflation method, a calender method, a T-die method, etc.

In the T-die method, a molten thermoplastic resin is extruded into a sheet or film form from a die having slit-shaped ribs, and the extruded molten thermoplastic resin is sandwiched between two metal rolls, cooled and solidified and taken out at the same time to produce a resin film method (see Patent Document 1, etc.). Such a T-die method can manufacture a resin film with good thickness precision compared with other manufacturing methods of a resin film, and since the use of an organic solvent is unnecessary and environmental load is small, it is a manufacturing method of a resin film. It is widely employed.

Japanese Patent Laid-Open No. 2011-089027

However, in the T-die method, since the molten thermoplastic resin is extruded from a very thin slit, it is easy to become unstable that the molten thermoplastic resin flows from the manifold part and the delta part to the die end side due to the resin pressure inside the die. Due to the difference in the resin flow rate between the vicinity of the die center and the die end, the extruded sheet or film molten thermoplastic resin tends to be thicker on the center side than on the end side, and edge wobble commonly called draw resonance phenomenon. (edge oscillation) arises and it becomes a big factor which greatly reduces the thickness precision of the resin film obtained.

In addition, since the distance (air gap) from when the molten thermoplastic resin is extruded through the ribs (slits) of the die to being sandwiched between the metal rolls is relatively long and the amount of take-off is large, the neck-in (neck-in) of the molten thermoplastic resin is A phenomenon called in) occurs. The neck-in phenomenon is a shrinkage phenomenon in a direction (width direction) perpendicular to the flow direction when the molten thermoplastic resin is taken up (stretched) and molded to a predetermined thickness in the conveyance direction (flow direction) of the extruded molten thermoplastic resin. Since this neck-in phenomenon narrows the width that can be adopted as a product (or is collected by excision of both ends), in addition to lowering the production efficiency of the resin film, the difference in the shrinkage rate between the end and the center of the resin film , causing the central portion to be thicker than the end portion.

Even if the resin film obtained by the T-die extrusion method has favorable thickness precision compared with the resin film obtained by other molding methods by these phenomena, the thickness precision cannot be said to be sufficient for use as an optical film.

Therefore, the objective of this invention is providing the manufacturing method of the thermoplastic resin film which has high thickness precision.

MEANS TO SOLVE THE PROBLEM The present inventors came to complete this invention, as a result of repeating earnest examination in order to solve the said subject.

That is, this invention includes the following structures.

(1) A method for producing a thermoplastic resin film in which a sheet-like molten thermoplastic resin material extruded from a die is sandwiched between two cooling rolls and molded, wherein the outer peripheral surface of both ends of at least one of the two cooling rolls has a roll Step portions having an outer diameter smaller than the outer diameter of the central portion are respectively formed on the periphery, and when the molten thermoplastic resin material is sandwiched between the two cooling rolls, also sandwiched between the step portion and the other cooling roll, the molten thermoplastic resin A method for producing a thermoplastic resin film, wherein a linear pressure applied by the material between the step portion and the other cooling roll is substantially 0 kgf/cm.

(2) The thermoplastic resin material as described in (1) above, wherein the thermoplastic resin material contains at least one thermoplastic resin selected from the group consisting of acrylic resins, polycarbonate resins, styrene resins, and methyl methacrylate-styrene resins. A method for producing a thermoplastic resin film.

(3) The method for producing a thermoplastic resin film according to (1) or (2), wherein the step portion has a step difference of 0.01 to 0.2 mm.

(4) The method for producing a thermoplastic resin film according to any one of (1) to (3), wherein at least one of the two cooling rolls is an elastic roll having a metal thin film on its outer peripheral surface.

(5) The method for producing a thermoplastic resin film according to any one of (1) to (4), wherein the thermoplastic resin material contains rubber particles.

(6) A thermoplastic resin film that can be produced or produced by the method for producing a thermoplastic resin film according to any one of (1) to (5) above.

According to the present invention, a step portion is provided at both ends of at least one of the two cooling rolls, and the linear pressure received by the molten thermoplastic resin material between the step portion and the other cooling roll is substantially 0 kgf/cm, and the thickness difference between the central portion becomes small, and a thermoplastic resin film having high thickness precision can be obtained. Moreover, since organic solvents, such as methylene chloride and methanol, are not used, the load on the environment is small.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic explanatory drawing which shows one Embodiment of the manufacturing method of this invention.
It is a schematic cross-sectional explanatory drawing which shows the roll structure which concerns on one Embodiment of this invention.
Fig. 3 is a schematic front view showing a cooling roll in which a step portion is formed.

In the method for producing a thermoplastic resin film of the present invention, a sheet-like molten thermoplastic resin material extruded from a die (that is, a thermoplastic resin material or composition in a molten state) is sandwiched between two predetermined cooling rolls and molded to have high thickness precision. A method for manufacturing a thermoplastic resin film. Moreover, in this invention, what is necessary is just to contain a thermoplastic resin as a main component as a thermoplastic resin material. A main component means the component whose content rate in the material exceeds 50 %.

(Thermoplastic material)

The thermoplastic resin contained as a main component in the thermoplastic resin material is not particularly limited as long as it is a resin capable of melt processing. For example, acrylic resin, polycarbonate resin, styrene resin, methyl methacrylate-styrene resin, cyclic resin olefin-based resins, polyester-based resins, acrylonitrile-styrene copolymer (AS)-based resins, acrylonitrile-butadiene-styrene copolymer (ABS)-based resins, and the like, among others, acrylic resins and polycarbonate-based resins It is preferable that it is at least 1 sort(s) selected from the group which consists of resin, a styrene resin, and methyl methacrylate-styrene-type resin.

<Acrylic resin>

As acrylic resin, methacryl resin etc. are used, for example. A methacrylic resin is a polymer mainly having a methacrylic acid ester, The homopolymer of a methacrylic acid ester may be sufficient, and a copolymer of 50 weight% or more of methacrylic acid ester and 50 weight% or less of other monomers may be sufficient as it. Here, as methacrylic acid ester, the alkylester of methacrylic acid is used normally.

A preferred monomer composition of the methacrylic resin is 50 to 100 wt% of alkyl methacrylate, 0 to 50 wt% of alkyl acrylate, and 0 to 49 wt% of monomers other than these, more preferably based on all monomers. Preferably, it is 50 to 99.9 weight% of alkyl methacrylate, 0.1 to 50 weight% of alkyl acrylate, and 0 to 49 weight% of monomers other than these. However, the sum total of a monomer does not exceed 100 weight%.

Examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and the like, and the alkyl group has usually 1 to 8 carbon atoms, preferably Usually it is 1-4. Among them, methyl methacrylate is preferably used.

Examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and the alkyl group has 1 to 8 carbon atoms, and preferably 1 to 4 carbon atoms.

The monomer other than alkyl methacrylate and alkyl acrylate, for example, may be a monofunctional monomer, that is, a compound having one polymerizable carbon-carbon double bond in the molecule, or a polyfunctional monomer, that is, polymerizable carbon-in the molecule. The compound which has at least two carbon double bonds may be sufficient, and a monofunctional monomer is used especially preferably.

As this monofunctional monomer, For example, Styrene-type monomers, such as styrene, (alpha)-methylstyrene, vinyltoluene; Alkenyl cyanide, such as acrylonitrile and methacrylonitrile; Acrylic acid, methacrylic acid, maleic anhydride, N-substituted maleimide, etc. are mentioned.

Moreover, as a polyfunctional monomer, For example, polyunsaturated carboxylic acid ester of polyhydric alcohols, such as ethylene glycol dimethacrylate, butanediol dimethacrylate, and trimethylol propane triacrylate; alkenyl esters of unsaturated carboxylic acids such as allyl acrylate, allyl methacrylate, and allyl cinnamate; polyalkenyl esters of polybasic acids such as diallyl phthalate, diallyl maleate, triallyl cyanurate and triallyl isocyanurate; Aromatic polyalkenyl compounds, such as divinylbenzene, etc. are mentioned.

In addition, alkyl methacrylate, alkyl acrylate, and monomers other than these may use 2 or more types of these as needed, respectively.

It is preferable that the heat distortion temperature (glass transition temperature) of a methacryl resin is 70 degreeC or more from a heat resistant viewpoint, It is more preferable that it is 80 degreeC or more, Furthermore, it is preferable that it is 90 degreeC or more. This glass transition temperature can be set suitably by adjusting the kind of monomer and its ratio.

A methacryl resin can be prepared by superposing|polymerizing a monomer component by methods, such as suspension polymerization, emulsion polymerization, and block polymerization. In that case, in order to obtain a preferable glass transition temperature or in order to acquire melt viscosity which shows the moldability into a preferable laminated body, it is preferable to use a suitable chain transfer agent at the time of superposition|polymerization. What is necessary is just to determine the addition amount of a chain transfer agent suitably according to the kind, its ratio, etc. of a monomer.

<Polycarbonate-based resin>

As the polycarbonate-based resin, for example, an aromatic polycarbonate-based resin excellent in heat resistance, mechanical strength, transparency, and the like is preferably used.

As aromatic polycarbonate-type resin, resin obtained by making a dihydric phenol and a carbonate precursor react by the interfacial polycondensation method and a melt transesterification method, for example; Resin obtained by polymerizing a carbonate prepolymer by the solid-phase transesterification method; Resin obtained by superposing|polymerizing by the ring-opening polymerization method of a cyclic carbonate compound, etc. are mentioned.

Examples of the dihydric phenol include hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, bis(4-hydroxyphenyl)methane, bis{(4-hydroxy-3,5- Dimethyl)phenyl}methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2,2-bis(4-hydroxyphenyl) propane (common name bisphenol A), 2,2-bis{(4-hydroxy-3-methyl)phenyl}propane, 2,2-bis{(4-hydroxy-3,5-dimethyl)phenyl}propane, 2 ,2-bis{(4-hydroxy-3,5-dibromo)phenyl}propane, 2,2-bis{(3-isopropyl-4-hydroxy)phenyl}propane, 2,2-bis{ (4-hydroxy-3-phenyl)phenyl}propane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)-3-methylbutane, 2,2- bis(4-hydroxyphenyl)-3,3-dimethylbutane, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 2,2-bis(4-hydroxyphenyl)pentane, 2, 2-bis(4-hydroxyphenyl)-4-methylpentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-4-isopropylcyclohexane , 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis{(4-hydroxyl -3-methyl)phenyl}fluorene, α,α′-bis(4-hydroxyphenyl)-o-diisopropylbenzene, α,α′-bis(4-hydroxyphenyl)-m-diisopropyl Benzene, α,α′-bis(4-hydroxyphenyl)-p-diisopropylbenzene, 1,3-bis(4-hydroxyphenyl)-5,7-dimethyladamantane, 4,4′- Dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylsulfoxide, 4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxydiphenylketone, 4,4'- and dihydroxydiphenyl ether and 4,4'-dihydroxydiphenyl ester, which may be used alone or in combination of two or more.

Among them, bisphenol A, 2,2-bis{(4-hydroxy-3-methyl)phenyl}propane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyl Phenyl)-3-methylbutane, 2,2-bis(4-hydroxyphenyl)-3,3-dimethylbutane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 1,1- A dihydric phenol selected from the group consisting of bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane and α,α′-bis(4-hydroxyphenyl)-m-diisopropylbenzene is used alone or two or more types are preferred, and in particular, single use of bisphenol A, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, and bisphenol A, 2,2- with at least one dihydric phenol selected from the group consisting of bis{(4-hydroxy-3-methyl)phenyl}propane and α,α′-bis(4-hydroxyphenyl)-m-diisopropylbenzene; Combination is preferred.

As the carbonate precursor, for example, carbonyl halide, carbonate ester, or haloformate is used, and specific examples thereof include phosgene, diphenyl carbonate, or dihaloformate of dihydric phenol.

<Styrene-based resin>

The styrene-based resin is a polymer containing 50% by mass or more, preferably 70% by mass or more of styrene units as its structural unit, and is a monofunctional polymer that partially copolymerizes with styrene as long as it contains 50% by mass or more of styrene units. The copolymer substituted with the unsaturated monomer unit may be sufficient.

As a styrene unit, For example, halogenated styrenes, such as chlorostyrene and a bromostyrene other than styrene; It is a compound which has a styrene skeleton, such as substituted styrene, such as alkylstyrenes, such as vinyltoluene and (alpha)-methylstyrene, and has one radically polymerizable double bond in a molecule|numerator.

Examples of the monofunctional unsaturated monomer copolymerizable with styrene include methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, methacrylic acid methacrylic acid esters such as 2-ethylhexyl and 2-hydroxyethyl methacrylate; acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate; unsaturated acids such as methacrylic acid and acrylic acid; (alpha)-methylstyrene, methacrylonitrile, maleic anhydride, phenyl maleimide, cyclohexyl maleimide, etc. are mentioned. Moreover, this copolymer may contain the glutaric anhydride unit and the glutarimide unit further.

<Methyl methacrylate-styrene-based resin>

The methyl methacrylate-styrene-based resin is, for example, a copolymer having a styrene unit content of 20 to 95 mass% and a methyl methacrylate unit content of 80 to 5 mass%, preferably a styrene unit content of 70 mass% or more and A copolymer etc. with a methyl methacrylate unit content of 30 mass % or less are mentioned. As a styrene unit, the styrene unit described in the said styrene resin can be used.

<Cyclic Olefin-Based Resin>

Examples of the cyclic olefin-based resin include various cyclic olefin polymers including a hydride of a ring-opened polymer of dicyclopentadiene, various cyclic olefin copolymers including a copolymer of dicyclopentadiene or tetracyclododecene and ethylene, and the number thereof. A thermoplastic resin having a unit of a monomer composed of a cyclic olefin, such as, for example, norbornene or a polycyclic norbornene-based monomer, as at least one selected from a digested product, a norbornene-based polymer, and the like, the cyclic olefin It may be a hydrogenated product of a ring-opened polymer or a ring-opened copolymer using two or more types of cyclic olefins, or may be an addition copolymer of a cyclic olefin and an aromatic compound having a chain olefin or a vinyl group. Moreover, a polar group may be introduce|transduced.

In the case of a copolymer of a cyclic olefin and an aromatic compound having a chain olefin or a vinyl group, examples of the chain olefin include ethylene and propylene. Examples of the aromatic compound having a vinyl group include For example, styrene, (alpha)-methylstyrene, nuclear alkyl-substituted styrene, etc. are mentioned. Such a copolymer WHEREIN: The unit of the monomer which consists of a cyclic olefin may be 50 mol% or less, for example, about 15-50 mol% may be sufficient. In particular, in the case of a ternary copolymer of a cyclic olefin, a chain olefin, and an aromatic compound having a vinyl group, the number of monomer units made of the cyclic olefin may be relatively small as described above. In such a terpolymer, the monomer unit composed of a chain olefin is usually 5 to 80 mol%, and the monomer unit composed of an aromatic compound having a vinyl group is usually 5 to 80 mol%.

Commercially available thermoplastic cyclic olefin resins include "Topas" manufactured by Ticona, "Aton" manufactured by JSR Co., Ltd., "ZEONOR" and "ZEONEX" manufactured by Nippon Zeon Co., Ltd. ', Mitsui Chemicals Co., Ltd. "Apel" etc. (all are brand names) are mentioned.

Moreover, as cyclic olefin resin, a glass transition point is 100 degreeC or more, Preferably 130 degreeC or more is preferable.

<Polyester resin>

Examples of the polyester resin include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene terephthalate/isophthalate copolymer, crystalline polyester, and non Qualitative polyester etc. are mentioned.

Such polyester-based resin is obtained, for example, by polycondensing a dibasic acid and a polyhydric alcohol.

Examples of the dibasic acid include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid; Aliphatic dicarboxylic acids, such as adipic acid, etc. are mentioned.

Moreover, as polyhydric alcohol, ethylene glycol, propanediol, 1, 4- butanediol, 1, 4- cyclohexane dimethanol, pentaethylene glycol, 2, 2- dimethyltrimethylene glycol, hexamethylene glycol, neo is, for example, Diols, such as pentyl glycol, are mentioned.

A dibasic acid and polyhydric alcohol are used by arbitrary combinations. Specifically, terephthalic acid/ethylene glycol copolymer, terephthalic acid/ethylene glycol/1,4-cyclohexanedimethanol ternary copolymer, 2,6-naphthalenedicarboxylic acid/ethylene glycol copolymer, terephthalic acid/1,4- A butanediol copolymer etc. are mentioned.

Commercially available crystalline polyesters include, for example, "Vylon" manufactured by Toyo Spinning Co., Ltd., and commercially available amorphous polyesters include, for example, amorphous polyethylene terephthalate (so-called APET) and a terephthalic acid/ethylene glycol/1,4-cyclohexanedimethanol ternary copolymer ("PETG" manufactured by Eastman Chemical Co., Ltd., etc.), etc. are mentioned.

<AS-based resin>

Examples of the AS-based resin include a copolymer in which a monomer unit derived from acrylonitrile and a monomer unit derived from styrene are randomly copolymerized. The content of the monomer unit derived from acrylonitrile is usually 2 to 50% by weight (that is, the content of the monomer unit derived from styrene is usually 98 to 50% by weight), and preferably 20 to 30% by weight. (That is, the content of the monomer unit derived from styrene is preferably 80 to 70 wt%). However, the total of the monomer units contained in AS-type resin shall be 100 weight%.

<ABS-based resin>

Examples of the ABS-based resin include a copolymer obtained by graft polymerization of an olefin-based rubber (eg, polybutadiene rubber) to the aforementioned AS-based resin in an amount of 40% by weight or less.

Further, in the case of containing rubber particles described later, in order to obtain good transparency, from the viewpoint of bringing the value of the refractive index of the resin component close to the value of the refractive index of the rubber component, styrene and methyl methacrylate and other copolymerizable monomers as the resin component So-called transparent ABS used as a copolymer of

As another copolymerizable monomer used when forming ABS-type resin, acrylonitrile is mentioned, for example. Moreover, about transparent ABS-type resin, what was disclosed by Unexamined-Japanese-Patent No. 2006-265406 is mentioned, for example.

Additives such as rubber particles, light diffusing agent, gloss remover, ultraviolet absorber, surfactant, impact resistance agent, polymer type antistatic agent, antioxidant, flame retardant, lubricant, dye and pigment to the thermoplastic resin material according to the purpose You may contain 1 type or in combination of 2 or more types arbitrarily.

<Rubber Particles>

The thermoplastic resin material preferably contains rubber particles (or particles comprising at least an elastic polymer). Thereby, impact resistance can be provided to the thermoplastic resin film obtained.

Here, as the rubber particles, for example, acrylic rubber particles, butadiene rubber particles, styrene-butadiene rubber particles, etc. can be used, and among them, acrylic rubber particles are preferable in terms of weather resistance and durability.

Acrylic rubber particles have a layer (elastomeric layer) made of an elastic polymer mainly composed of an acrylic acid ester, and may be single-layered particles made of only an elastic polymer, or a layer made of an elastic polymer layer and a hard polymer (hard polymer layer). The particle|grains of the multilayer structure comprised may be sufficient, and 1 type or 2 or more types of acrylic rubber particles may be mixed and used.

When the acrylic rubber particles have a multilayer structure, the layer structure includes, for example, a two-layer structure comprising an inner layer (elastomeric layer)/outer layer (hard polymer layer), an inner layer (hard polymer layer)/outer layer (elasticity) A two-layer structure consisting of a polymer layer), a three-layer structure consisting of an innermost layer (hard polymer layer)/intermediate layer (elastomeric layer)/outermost layer (hard polymer layer), innermost layer (elastomeric layer)/intermediate layer (hard polymer layer) )/outermost layer (elastomeric layer), innermost layer (elastomeric layer)/inner layer side intermediate layer (hard polymer layer)/outer layer side intermediate layer (elastomeric polymer layer)/outermost layer (hard polymer layer) A four-layer structure, etc. are mentioned. Further, in the structure in which the outermost of these layer structures is a hard polymer layer, the outermost structure is covered with a hard polymer layer having a different composition, specifically, the innermost layer (elastomer layer)/intermediate layer (hard polymer layer)/ A three-layer structure comprising an outermost layer (hard polymer layer), four layers comprising innermost layer (hard polymer layer)/inner layer side intermediate layer (elastomeric layer)/outer layer side intermediate layer (hard polymer layer)/outermost layer (hard polymer layer) structure or the like.

The elastomeric part in the acrylic rubber particles is a part containing at least an elastic polymer, and when the acrylic rubber particles have a single-layer structure of an elastic polymer, it means all of the acrylic rubber particles, and when the acrylic rubber particles have a multi-layer structure , means the outermost elastomer layer among the layers constituting the acrylic rubber particles and the inner elastomer layer covered by the elastomer layer.

The elastic polymer layer constituting the acrylic rubber particles is preferably formed of an elastic polymer obtained by polymerizing a monomer component containing an alkyl acrylate and a polyfunctional monomer, and optionally also containing an alkyl methacrylate or other monofunctional monomer. .

As an alkyl acrylate used when forming an elastic polymer layer, carbon number of an alkyl group is 1-8 normally, Preferably it is 1-4, for example, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate. etc. are mentioned, These may be used 1 type or in mixture of 2 or more types.

The polyfunctional monomer used when forming the elastic polymer layer is a compound having two or more radically polymerizable double bonds in the molecule, and specifically, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, butanediol di polyunsaturated carboxylic acid esters of polyhydric alcohols such as methacrylate, ethylene glycol diacrylate, 1,2-propylene glycol diacrylate, 1,3-propylene glycol diacrylate, and trimethylolpropane triacrylate; alkenyl esters of unsaturated carboxylic acids such as allyl acrylate, allyl methacrylate, and allyl cinnamate; polyalkenyl esters of polybasic acids such as diallyl phthalate, diallyl maleate, triallyl cyanurate and triallyl isocyanurate; Aromatic polyalkenyl compounds, such as divinylbenzene, etc. are mentioned, These may be used 1 type or in mixture of 2 or more types.

As alkyl methacrylate used arbitrarily when forming an elastic polymer layer, carbon number of an alkyl group is 1-8 normally, Preferably it is 1-4, For example, methyl methacrylate, ethyl methacrylate, methacrylic acid. butyl acid, 2-ethylhexyl methacrylate, etc. are mentioned, These may be used 1 type or in mixture of 2 or more types.

As another monofunctional monomer arbitrarily used when forming an elastic polymer layer, For example, Aromatic alkenyl compounds, such as styrene, (alpha)-methylstyrene, vinyltoluene; alkenyl cyanide compounds such as acrylonitrile and methacrylonitrile; Acrylic acid, methacrylic acid, maleic anhydride, N-substituted maleimide etc. are mentioned, These may be used 1 type or in mixture of 2 or more types.

A preferable composition of the monomer component forming the elastic polymer layer in the acrylic rubber particles is, for example, 50 to alkyl acrylate with respect to the total amount of alkyl acrylate, polyfunctional monomer, alkyl methacrylate, and other monofunctional monomers. 99.9 weight%, 0.1 to 10 weight% of a polyfunctional monomer, 0 to 49.9 weight% of alkyl methacrylate, and the other monofunctional monomer are the ratios of 0 to 49.9 weight%. However, the total of monomer components does not exceed 100 weight%.

The hard polymer layer constituting the acrylic rubber particles usually contains alkyl methacrylate and, if necessary, is formed of a hard polymer formed by polymerizing a monomer component containing alkyl acrylate and other monofunctional or polyfunctional monomers. it is preferable

Examples of the alkyl methacrylate, alkyl acrylate, and other monofunctional and polyfunctional monomers used when forming the hard polymer layer include alkyl methacrylate, alkyl acrylate, other monofunctional monomers and polyfunctional monomers constituting the elastic polymer layer. as the same as those described above.

The preferable composition of the monomer component forming the hard polymer layer in the acrylic rubber particles is, for example, when the hard polymer layer is outside the elastic polymer part, alkyl methacrylate, alkyl acrylate, other monofunctional monomers; and 50 to 100% by weight of alkyl methacrylate, 0 to 50% by weight of alkyl acrylate, 0 to 50% by weight of other monofunctional monomers, and 0 to 10% by weight of polyfunctional monomers with respect to the total amount of the polyfunctional monomer. , when the hard polymer layer is present inside the elastomer section (that is, when the elastomer section contains the hard polymer layer), with respect to the total amount of alkyl methacrylate, alkyl acrylate, other monofunctional monomers, and polyfunctional monomers. , 70 to 100% by weight of alkyl methacrylate, 0 to 30% by weight of alkyl acrylate, 0 to 30% by weight of other monofunctional monomers, and 0 to 10% by weight of polyfunctional monomers. However, the total of monomer components does not exceed 100 weight%.

When the acrylic rubber particles have a multilayer structure, the weight ratio of the elastic polymer layer and the hard polymer layer is not particularly limited, and for example, the ratio of the adjacent elastic polymer layer and the hard polymer layer is based on 100 parts by weight of the elastic polymer. , the hard polymer is usually 10 to 400 parts by weight, preferably 20 to 200 parts by weight.

Acrylic rubber particles can be prepared by polymerizing the monomer component forming the elastic polymer in at least one reaction by an emulsion polymerization method or the like.

For example, when preparing acrylic rubber particles having a three-layer structure consisting of innermost layer (hard polymer layer)/middle layer (elastomeric layer)/outermost layer (hard polymer layer), first, the hard polymer layer serving as the innermost layer A hard polymer is obtained by polymerizing the monomer component forming the elastomer in at least one stage reaction by an emulsion polymerization method, etc. It is polymerized and grafted onto a hard polymer. Then, in the presence of the resulting elastic polymer layer, the monomer component forming the hard polymer is polymerized in at least one stage by an emulsion polymerization method or the like to graft onto the elastic polymer. In addition, when superposing|polymerizing each layer in 2 or more stages, respectively, not all of the monomer compositions of each stage, but the monomer composition as a whole should just be within a predetermined range.

Regarding the particle diameter of the acrylic rubber particles, the average particle diameter of the layer of the elastic polymer mainly composed of acrylic acid ester in the rubber particles is preferably 0.01 to 0.4 μm, more preferably 0.05 to 0.3 μm, still more preferably 0.07 ∼ 0.25 μm.

In addition, the average particle diameter is the diameter of the dyed part by mixing acrylic rubber particle with a methacrylic resin, forming a film, performing dyeing of the elastic polymer layer with ruthenium oxide in the cross section, and observing with an electron microscope. can be obtained from

That is, when acrylic rubber particles are mixed with methacryl resin and the cross section is dyed with ruthenium oxide, the matrix methacrylic resin is not dyed, and when a hard polymer layer exists outside the elastomer layer, this hard polymer layer Since there is no dyeing and only the elastomer layer is dyed, the particle diameter can be obtained from the diameter of the portion observed in the substantially circular shape of the thus-dyed elastomer layer by an electron microscope. When the hard polymer layer is present inside the elastomer layer, the hard polymer is not dyed, and a state of a two-layer structure in which the outer elastomer layer is dyed is observed. In this case, the outer side of the two-layer structure is observed. , that is, it can be thought of as the outer diameter of the layer of the elastomer.

The content ratio of rubber particles in the thermoplastic resin material may be appropriately adjusted so that the impact resistance of the thermoplastic resin film is desired. Preferably it is 30 weight% or less, Preferably it is 5 weight% or more, More preferably, it is 10 weight% or more, When the rubber particle consists of a single-layer structure, it is usually 80 weight% with respect to the total amount of a thermoplastic resin material. or less, preferably 70 weight% or less, preferably 30 weight% or more, and more preferably 50 weight% or more.

(Method for producing a thermoplastic resin film)

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of the manufacturing method of the thermoplastic resin film of this invention is described with reference to drawings. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic explanatory drawing which shows one Embodiment of the manufacturing method of this invention. It is a schematic cross-sectional explanatory drawing which shows the roll structure which concerns on one Embodiment of this invention. Fig. 3 is a schematic front view showing a cooling roll having a stepped portion that can be used in one embodiment of the present invention.

In the present invention, first, the above-mentioned thermoplastic resin material is put into the extruder 1 and melt-kneaded, and as shown in Fig. 1, from the tip (lip) of the T-die 2, a sheet-like molten thermoplastic resin material ( 3) is extruded.

As the extruder 1, a single screw extruder, a twin screw extruder, etc. are mentioned, for example. Moreover, when manufacturing the multilayered thermoplastic resin film which consists of two or more layers, you may use several extruder. For example, in the case of producing a three-layer thermoplastic resin film, each thermoplastic resin material is melt-kneaded using three or two extruders, and the molten thermoplastic resin material is formed into three types and three layers. Dispense with a distributive or two or three layer distribution feed block (not shown), may be co-extruded by flowing into a single-layer T-die, and each molten thermoplastic material is fed separately into a multi-manifold die and 3 in front of the lip It may be distributed in a layered constitution and coextruded.

In the extruder 1, a screen mesh for filtering and removing the comparatively large foreign material etc. in a thermoplastic resin material suitably; a polymer filter for filtering and removing relatively small foreign substances, gels, etc. in the thermoplastic resin material; You may provide a gear pump etc. for stably quantifying the amount of resin to extrude.

The T-die 2 is a die having a slit-shaped lip, and examples thereof include a feed block die, a manifold die, a fish tail die, a coat hanger die, and a screw die. When manufacturing a multilayered thermoplastic resin film, you may use a multi-manifold die etc.

Moreover, the length in particular of the width direction of the lip|rip of the T-die 2 is although there is no restriction|limiting, It is preferable that it is 1.2-1.5 times with respect to the product width. The opening degree of the lip may be appropriately adjusted according to the thickness of the desired product, but is usually 1.01 to 10 times the thickness of the desired product, preferably 1.1 to 5 times. It is preferable to adjust the opening degree of the lip with bolts arranged in the width direction of the T-die 2 . The lip opening degree does not need to be constant in the width direction, and for example, the draw resonance phenomenon can be suppressed by adjusting the lip opening degree of the edge part to be narrower than the lip opening degree of the center part.

Then, the extruded sheet-like molten thermoplastic resin material 3 is sandwiched between the two cooling rolls 4 and 5 and molded.

<Cool roll>

The two cooling rolls 4 and 5 may be mutually metal rolls or mutually elastic rolls, one of which may be a metal roll, and the other may be an elastic roll, and among them, high thickness precision can be imparted to the resin film obtained. It is preferable that one is a metal roll and the other is an elastic roll from a point.

It will not specifically limit if it is high rigidity as a metal roll, For example, a drilled roll, a spiral roll, etc. are mentioned. The surface state of a metal roll is not specifically limited, For example, a mirror surface may be sufficient and a pattern, an unevenness|corrugation, etc. may exist.

Examples of the elastic roll include a rubber roll and an elastic roll having a thin metal film on its outer circumferential surface (hereinafter, may be referred to as a metal elastic roll), and among these, a metal elastic roll is preferable.

As shown in FIG. 2, the metal elastic roll is arranged so that it may cover the outer peripheral surface of the shaft roll 7 formed so that it can rotate freely in a substantially cylindrical shape, and this shaft roll 7, and to the molten thermoplastic resin material 3 It consists of a cylindrical metal thin film 8 in contact, and the fluid 9 enclosed between these shaft rolls 7 and the metal thin film 8, and the metallic elastic roll exhibits elasticity by the fluid 9. FIG.

The shaft roll 7 is not specifically limited, For example, it consists of stainless steel etc.

It is preferable that the metal thin film 8 consists of stainless steel etc., for example, and the thickness is about 2-5 mm. It is preferable that the metal thin film 8 has flexibility, flexibility, etc., and it is preferable that it is a seamless structure without a weld joint. The metal elastic roll provided with such a metal thin film 8 is excellent in durability, and when the metal thin film 8 is mirror-finished, the same handling as a normal mirror-finished roll can be performed, and the metal thin film 8 has a shape and If the unevenness is provided, it becomes a roll on which the shape can be transferred, so it is convenient to use.

The fluid 9 is not particularly limited as long as it is a fluid, and examples thereof include water and oil. In the case of water, it is preferably used at the time of setting a roll temperature of 100°C or lower, and can also be applied to a roll temperature of 100°C or higher by, for example, applying pressure to make pressurized water. Moreover, when setting to a higher roll temperature, the direction of oil is used preferably.

In general, since the width of the cooling roll is longer than the width of the sheet-shaped molten thermoplastic resin material 3, the sheet-shaped molten thermoplastic resin material 3 receives a force over the entire width in the width direction. A step portion is formed circumferentially on the outer peripheral surface of both ends of at least one of the rolls 4 and 5, respectively. Further, in the present invention, when the sheet-like molten thermoplastic resin material 3 is sandwiched between the two cooling rolls 4 and 5, it can also be sandwiched between the step portion and the other cooling roll. That is, it may have a stepped part on the outer peripheral surface of the both ends of both cooling rolls 4 and 5, respectively, or you may have a stepped part on the outer peripheral surface of both ends of only one cooling roll, respectively. Among them, the latter is preferable, and in particular, it is preferable that the cooling roll on which the step portion is not formed is a metallic elastic roll, and the cooling roll having the step portion is preferably a metal roll. As described above, since the outer periphery of the metal elastic roll is made of a cylindrical metal thin film, it is difficult to form a step portion, and when the step portion is formed, the strength of the metal thin film becomes non-uniform, so the step portion is not a metal elastic roll, It is preferable to form on a metal roll.

In the present invention, the "outer diameter" of the step portion formed on the outer peripheral surface of both ends of the cooling roll 4 or 5 is smaller than the outer diameter of the roll center portion, and as shown in FIG. 3, the step (depth) at both ends of the roll When (S) is formed, the outer diameter of the step portion is represented by (the outer diameter of the roll center portion R-2S). The step S is appropriately set according to the thickness of the thermoplastic resin film to be produced, and is preferably 0.01 to 0.2 mm. The step S is more preferably 0.02 to 0.18 mm. When the step S is larger than 0.2 mm, the edge of the film tends to swell in a wavy shape, and the influence on the surface of the film is increased, and by extension, the film is liable to break. Further, the step S is more preferably in a range in which the relationship of 0.1T < S < 2.0T with respect to the average thickness T of the thermoplastic resin film is established. In addition, when the step (S) is 0.1 T or less with respect to the average thickness (T) of the thermoplastic resin film, the deviation (deviation) of the film thickness of the edge cannot be absorbed, and a linear pressure is applied, and furthermore, the thickness accuracy of the entire film is lowered. is likely to result in In addition, when the step S is 2.0T or more with respect to the average thickness T of the thermoplastic resin film, the edge of the film tends to wavy, and the influence on the surface of the film increases, and furthermore, it is easy to cause breakage of the film. lose Further, the outer peripheral surface of the step portion may also be mirror-finished.

As for the cooling roll having a step portion, as shown in FIG. 3 , the width a1 in the step portion 10 of the cooling roll (that is, the portion overlapping with the sheet-shaped molten thermoplastic resin material 3) is 10 to 200 mm, preferably 20 to 100 mm, and the outer diameter of the central portion 11 excluding the step portion 10 of the cooling roll is preferably 200 to 500 mm. The width a2 in the central portion 11 excluding the step 10 of the cooling roll is the width a1 of the width of the sheet-like molten thermoplastic resin material 3 and the step 10 of the cooling roll. What is necessary is just to adjust suitably from, In this case, it is preferable that the width (a1) is in the said range.

The shape of the step portion 10 is not particularly limited, and, for example, as shown in FIG. 3 , the outer diameter of the step portion 10 of the cooling roll is a constant shape, and is inclined from the central portion 11 side to the end portion. and an inclined shape formed by . Among them, it is preferable that the outer diameter of the step portion 10 of the cooling roll has a constant shape from the viewpoint of ease of processing of the roll.

The step (or depth) S in the step portion 10 is the molten thermoplastic resin material 3 when the sheet-like molten thermoplastic resin material 3 is sandwiched between the two cooling rolls 4 and 5. It is not particularly limited as long as the linear pressure, which will be described later, received between the temporary step portion 10 and the other cooling roll is substantially 0 kgf/cm, and may vary depending on the desired thickness of the thermoplastic resin film, but the step S is 0.005 to It is preferable that it is 0.5 mm, It is more preferable that it is 0.01-0.2 mm, It is more preferable that it is 0.02-0.1 mm. When the step S exceeds 0.5 mm, the processing time and cost for cutting the cooling roll are increased, and there is a fear that the improvement of the additional effect commensurate with the processing time and cost may not be seen. On the other hand, if it is less than 0.005 mm, when the sheet-like molten thermoplastic resin material 3 is sandwiched between two cooling rolls, a linear pressure is also applied to the step portion formed at the end of the resin 3, making it difficult to improve the thickness accuracy. There are concerns. When the step portion has a step (thickness) S of 0.01 to 0.2 mm, swell at the edge of the film can be prevented, the film surface can be made good, and furthermore, the breakage of the film can be prevented, and , the effect that the thickness precision of the whole film can be raised is acquired.

The surface temperature Tr of the cooling rolls 4 and 5 is, for example, (Th-55°C) ≤ Tr ≤ (Th+55°C) with respect to the thermal deformation temperature (Th) of the thermoplastic resin described above and later. ), preferably (Th - 20 °C) ≤ Tr ≤ (Th + 20 °C), more preferably (Th - 15 °C) ≤ Tr ≤ (Th + 10 °C), even more preferably (Th - 10 ℃) ≤ Tr ≤ (Th + 5 ℃) is preferably set. When the surface temperature (Tr) is lower than (Th-55°C), the heat shrinkability of the thermoplastic resin increases, there is a risk that a resin film with high thickness precision cannot be obtained, and the surface temperature (Tr) is (Th+55°C) When it is higher, there exists a possibility that the peeling mark from a cooling roll may become conspicuous.

In addition, as heat distortion temperature (Th) of a thermoplastic resin, it determines with the composition of a thermoplastic resin, and is about 60-200 degreeC normally. The thermal deformation temperature (Th) of a thermoplastic resin is a temperature measured based on ASTM D-648.

In addition, when manufacturing a multilayered thermoplastic resin film, about surface temperature Tr, resin with the highest heat distortion temperature Th is taken as a reference.

The gap (roll gap) between the two cooling rolls is appropriately adjusted according to the desired product thickness, so that both sides of the sheet-like molten thermoplastic resin material 3 are on the surface of the central portion 11 of the cooling rolls 4 and 5, respectively. A roll gap is set so as to abut. Therefore, when the sheet-like molten thermoplastic resin material 3 is sandwiched between two cooling rolls, it receives a constant pressure from the central portion 11 of the cooling rolls 4 and 5 and is molded into a thermoplastic resin film.

This pressure is applied to the cooling rolls because, when the cooling rolls 4 and 5 are metal rolls, the central portion 11 of the cooling roll and the sheet-like molten thermoplastic resin material 3 are in line contact (in the width direction). The force can be defined as a value obtained by dividing the width of the portion actually under pressure of the sheet-like molten thermoplastic resin material (eg, width a2 in FIG. 3 ), and is expressed as a linear pressure (kgf/cm). The force applied to the cooling rolls is usually applied by an air cylinder (not shown) connected to both end surfaces of at least one of the first cooling rolls 4 and 5, respectively. The application of force to the cooling roll is not limited to the air cylinder, and may be a hydraulic cylinder or the like. In addition, the width of the portion actually under pressure of the sheet-like molten thermoplastic resin material is the width a2 of the central portion 11 of the cooling rolls (refer to FIG. 3 ) in the case of having step portions at both ends of the cooling rolls, respectively. ) indicates the width of the central portion 11 of the shorter cooling roll, and in the case of having stepped portions at both ends of only one cooling roll, the width of the central portion 11 of the cooling roll having stepped portions at both ends, respectively It points to (a2). Further, in the case where both ends of the cooling rolls each have step portions and the width a2 (see Fig. 3) of the central portion 11 of the cooling rolls is the same length, the width of the central portion 11 of the cooling rolls (a2) This becomes the width|variety of the part which is actually receiving pressure of a sheet-like molten thermoplastic resin material.

On the other hand, for example, as shown in FIG. 2, when one cooling roll is an elastic roll, or when both cooling rolls are elastic rolls, the surface of an elastic roll (in the case of a metallic elastic roll shown in FIG. 2, metal thin film) (8)) Indented by this pressure, the elastic roll and the sheet-like molten thermoplastic resin material 3 come into contact with the surface. Let's think about it using the definition of line pressure that is numerically divided by the width of the part.

In addition, the width of the part in formal contact of a sheet-like molten thermoplastic resin material is the same as the width (a1) of the part which is actually receiving pressure of the above-mentioned sheet-like molten thermoplastic resin material.

The linear pressure which the sheet-like molten thermoplastic resin material 3 receives from the center part 11 of two cooling rolls is 1-25 kgf/cm normally, it is preferable that it is 2-22 kgf/cm, and it is 5-20 It is more preferable that it is kgf/cm. When the linear pressure is less than 1 kgf/cm, the pressure becomes insufficient to press the surface of the molten thermoplastic resin material 3 to form a good surface, and there is a fear that a clean surface thermoplastic resin film with high thickness precision may not be obtained. there is On the other hand, when the linear pressure is larger than 25 kgf/cm, the shear force applied to the molten thermoplastic resin material 3 increases, so that the orientation of the molten thermoplastic resin material 3 increases, and there is a risk that the birefringence of the resulting thermoplastic resin film will increase. have.

Further, in the present invention, the linear pressure received by both ends of the molten thermoplastic resin material 3, that is, the linear pressure that the molten thermoplastic resin material 3 receives between the step portion 10 and the other cooling roll is substantially 0 (zero). ) to be. Further, even when the step portion 10 is provided at both ends of one cooling roll and the step portion 10 is also formed at both ends of the other cooling roll, the molten thermoplastic resin material 3 in the step portion 10 ), the linear pressure applied to both ends is substantially 0 (zero).

Here, that the linear pressure is substantially 0 (zero) means that when the molten thermoplastic resin material 3 is sandwiched between the cooling rolls 4 and 5, the molten thermoplastic resin material 3 contacts the step portion 10, This means that the surface shape of the step portion 10 is not transferred to the surface of the molten thermoplastic resin material 3 in contact with the step portion 10 .

Moreover, as shown in FIG. 2, when one cooling roll 4 is a metal elastic roll, and the other cooling roll 5 is a metal roll, the molten thermoplastic resin material 3 is interposed between a metal elastic roll and a metal roll. When sandwiched, the molten thermoplastic resin material 3 can be uniformly pressed in the width direction. That is, the elastic metal roll is elastically deformed in a concave shape along the outer circumferential surface of the metal roll via the molten thermoplastic resin material 3, and the elastic metal roll and the metal roll are sandwiched by the molten thermoplastic resin material 3 at a predetermined contact length. (In addition, the length L is actually the length of the curve along the curve of the roll. For convenience, as shown in FIG. 2 , the molten thermoplastic resin material 3 is sandwiched between the rolls. It is expressed as the straight-line distance between the point of loss and the point of departure from the roll). Thereby, the metallic elastic roll and the metallic roll are pressed in surface contact with the molten thermoplastic resin material 3, and the molten thermoplastic resin material sandwiched between these rolls is formed into a film while being uniformly pressed in a planar shape. When it forms into a film in this way, high thickness precision can be provided to the resin film obtained, and it can suppress that a distortion remains in a resin film.

As the contact length L, what is necessary is just a length which can pressurize the molten thermoplastic resin material 3 obtained uniformly in the width direction. Therefore, when the elastic metal roll is elastically deformed, the elastic metal roll should just be provided with the elasticity enough to be able to form such a contact length L.

The contact length L is preferably 1 to 20 mm, preferably 1 to 10 mm, more preferably 1 to 7 mm. In order to make the contact length L into a predetermined value, it can implement arbitrarily by adjusting the thickness of the metal thin film 8, the sealing amount of the fluid 9, etc., for example.

In the thermoplastic resin film obtained in this way, since the thickness precision of both ends of a film is lower than the thickness precision of a film center part, you may cut|disconnect both ends of a thermoplastic resin film.

Although the cutting method is not specifically limited, For example, the method of using the rotary shearing cutter which holds the cutter of a round blade from the upper and lower surfaces of a thermoplastic resin film is preferable from a viewpoint of preventing fracture|rupture of a thermoplastic resin film.

The structure of the thermoplastic resin film is not particularly limited, and may have a single layer structure or a plurality of layer structures. In the case of a plurality of layer structures, for example, a structure of two, three, or four or more layers of the same or different thermoplastic resin materials such as polycarbonate-based resin and acrylic resin may be employed.

The thickness of the resin film can be adjusted by the thickness of the molten thermoplastic resin material 3 extruded from the die 2 , the roll gap of the two cooling rolls 4 and 5 , and the like. The thickness of the resin film which can be manufactured by this invention is 0.02-0.5 mm, for example, Preferably it is 0.03-0.25 mm, More preferably, it is 0.04-0.1 mm.

The thermoplastic resin film can be suitably used for an optical film in a flat panel display such as a liquid crystal display device or a plasma display, etc. In particular, an optical formed by subjecting the surface of a base film to a surface treatment such as a hard coat treatment or an antiglare treatment. It can be used more preferably as this base film in a film.

Example

Hereinafter, although the Example of this invention is shown, this invention is not limited by these Examples. In the examples, percentages and parts indicating content or usage are based on weight unless otherwise specified.

The method of measuring the line pressure of the edge part in each Example is as follows.

When the sheet-like molten thermoplastic resin composition extruded from the die is sandwiched between the first and second cooling rolls, the pressure value of the air cylinder connected to both end surfaces of the second cooling roll is multiplied by the cross-sectional area of the cylinder. Let the total value of the values be the force applied to the second cooling roll, and the value obtained by dividing this force by the width of the sheet-like molten thermoplastic resin composition in contact with the second cooling roll is defined as the linear pressure (kgf/cm) at the end calculated. In addition, when there is a step portion at both ends of the second cooling roll, and the sheet-like molten thermoplastic resin composition does not contact the step portion (more specifically, the bottom of the step portion), or the composition contacts the step portion, but the step portion When the surface shape of the step portion was not transferred to the surface of the composition in contact with the , the linear pressure of the end was set to 0 kgf/cm.

The thickness precision evaluation of the thermoplastic resin film was performed on condition of the following.

<Thickness precision of the flow direction (MD) of the resin film>

The obtained resin film (length in the flow direction × length in the width direction = 1500 mm × 900 mm) is divided into 9 equal parts in the width direction, and the third row is a measurement sample (length in the flow direction × length in the width direction = 1500 mm × 100 mm) ) was set. Using a micrometer, the thickness was measured at 50 points in the flow direction at intervals of 30 mm, and from the maximum and minimum values of the measured thickness, and the average thickness of the 50 measured points, the amount of deviation of the thickness and the thickness precision It computed from the following formula.

Thickness variation (㎛) = Maximum thickness - Minimum thickness

Thickness accuracy (%) = thickness variation/average thickness × 100

<Thickness precision in the direction (TD) orthogonal to the flow direction of the resin film>

The obtained resin film (length of flow direction x width direction length = 1500 mm x 900 mm) was taken as a strip sample of 50 mm width in flow direction (length of flow direction x width direction length = 50 mm x 900 mm) was cut out in the width direction. Using a micrometer, the thickness of the strip sample was measured at 30 mm intervals in the width direction at 30 points, the maximum and minimum values of the thickness of the measured values, and the amount of deviation of the thickness from the average thickness of the 30 measured points, the thickness The precision was computed from the following formula.

Thickness variation (㎛) = Maximum thickness - Minimum thickness

Thickness accuracy (%) = thickness variation/average thickness × 100

The cooling rolls used by the following examples and comparative examples are as follows.

Cooling roll A: A stainless steel thin film with a mirror-finished thickness of 2 mm on one side is placed so that the mirror-finished surface is the outer surface of the roll so as to cover the outer periphery of the shaft roll made of stainless steel, and heat-heat oil ( A metal elastic roll (surface temperature: 87°C) having an outer diameter of 350 mm and a width of 1600 mm, in which a fluid composed of a thin film is sealed.

Cooling Roll B: A spiral metal roll made of stainless steel with a mirror-finished surface and having an outer diameter of 350 mm and a width of 1600 mm (with a spiral fluid passage therein) (surface temperature: 87°C).

Cooling roll C: As shown in FIG. 3 , the outer diameter of the central portion 11 is 350 mm, the width a2 of the central portion 11 is 1400 mm, and the surface of the outer peripheral surface at both ends has a step S of 50 µm. A spiral metal roll made of mirror-finished stainless steel (with a spiral fluid passage inside) (surface temperature: 87°C). In addition, the width a1 was about 100 mm.

In the following examples and comparative examples, polycarbonate resins, acrylic resins, and rubber particles shown below were used.

<Polycarbonate resin>

As a polycarbonate-type resin, "Calibur 300-15" (heat distortion temperature: 140 degreeC) by Sumitomo Dow Co., Ltd. was used.

<Acrylic resin>

As the acrylic resin, pellets of a thermoplastic polymer (heat distortion temperature of 104°C) obtained by bulk polymerization of a monomer composed of 97.8% of methyl methacrylate and 2.2% of methyl acrylate were used. In addition, this heat distortion temperature is a glass transition temperature, and is the extrapolated glass transition initiation temperature calculated|required with the heating rate of 10 degree-C/min by differential scanning calorimetry according to JISK7121:1987.

<Rubber Particles>

As rubber particles, the innermost layer is a hard polymer obtained by polymerization of a monomer composed of 93.8% methyl methacrylate, 6.0% methyl acrylate, and 0.2% allyl methacrylate, and the intermediate layer is butyl acrylate 81%, styrene 17%, and methacrylic acid. It is an elastic polymer obtained by polymerization of a monomer composed of 2% of allyl acid, and the outermost layer is a hard polymer obtained by polymerization of a monomer composed of 94% methyl methacrylate and 6% methyl acrylate, and the innermost layer/middle layer/outermost layer Rubber particles having a spherical three-layer structure by an emulsion polymerization method having a weight ratio of 35/45/20 and an average particle diameter of the elastic polymer layer of the intermediate layer of 0.22 µm were used.

In addition, the average particle diameter of the rubber particles is obtained by mixing rubber particles with methacrylic resin to form a film, dyeing the elastic polymer (intermediate layer) with ruthenium oxide in the cross section, and observing with an electron microscope, It was calculated from the diameter.

<Examples 1 to 3, Comparative Examples 1 to 3>

(Preparation of a single-layered resin film)

First, a thermoplastic resin composition was prepared as follows. That is, 70 parts of acrylic resin and 30 parts of rubber particles were mixed with a super mixer, it melt-kneaded with a twin screw extruder, and the thermoplastic resin composition which consists of an acrylic resin and rubber particle was obtained as pellets.

Next, the structure of a 1st cooling roll and a 2nd cooling roll was made into the roll structure shown in Table 1. Then, the thermoplastic resin composition obtained above was melted with a 120 mmφ single screw extruder (manufactured by Hitz Sangi Techno Co., Ltd.), and a T-die [manufactured by Hitz Sangi Techno Co., Ltd.] having a lip width of 1650 mm and a lip opening degree of 0.6 mm was prepared A sheet-like molten thermoplastic resin composition was extruded through the

The extruded sheet-like molten thermoplastic resin composition was sandwiched between the first cooling roll and the second cooling roll, and molded and cooled to obtain a resin film having a thickness shown in Table 1. Table 1 shows the linear pressures received at both ends of the cooling roll when the sheet-like molten thermoplastic resin composition was sandwiched between the first cooling roll and the second cooling roll. Moreover, the thickness precision of the obtained resin film was measured, and the result was shown in Table 1.

<Example 4, Comparative Example 4>

(Preparation of a resin film having a three-layer structure)

First, in the same manner as in <Examples 1 to 3 and Comparative Examples 1 to 3>, 70 parts of an acrylic resin and 30 parts of rubber particles are mixed with a super mixer, melt-kneaded with a twin screw extruder, and consist of an acrylic resin and rubber particles A thermoplastic resin composition was obtained as pellets.

Next, the structure of a 1st cooling roll and a 2nd cooling roll was made into the roll structure shown in Table 1. Then, the polycarbonate resin was melted with a 120 mmφ single screw extruder (manufactured by Hitz Sangi Techno Co., Ltd.), and the thermoplastic resin composition obtained above was melted with a 50 mmφ single screw extruder (manufactured by Hitz Sangi Techno Co., Ltd.), and these A thermoplastic resin composition was laminated on both sides of a polycarbonate resin through a feed block of two types, three-layer distribution type [manufactured by Hitz Sangi Techno Co., Ltd.], and a T-die [Hitz Sangi Techno ( Note) Manufacturing], a sheet-like molten thermoplastic resin composition comprising three layers was extruded.

The extruded sheet-like molten thermoplastic resin composition was sandwiched between the first cooling roll and the second cooling roll, and molded and cooled to obtain a resin film having a thickness shown in Table 1. Table 1 shows the linear pressures received at both ends of the cooling roll when the sheet-like molten thermoplastic resin composition was sandwiched between the first cooling roll and the second cooling roll. Moreover, the thickness precision of the obtained resin film was measured, and the result was shown in Table 1.

In the embodiment, step portions are respectively formed at both ends of one cooling roll among the two cooling rolls, and when the sheet-like molten thermoplastic resin composition is sandwiched between the two cooling rolls, the thermoplastic resin composition is formed with the stepped portion (bottom portion). ), and the line pressure of the edge part which the thermoplastic resin composition received was 0 kgf/cm. In the examples, since step portions were respectively formed at both ends of one of the two cooling rolls, and the line pressure at the end to which the sheet-like thermoplastic resin composition was received was 0 kgf/cm, the thermoplastic resin film obtained in each example The thickness precision of MD was 1.1 to 2.6%, and the thickness precision of TD was 0.4 to 1.6%, and was high thickness precision.

On the other hand, in the comparative example, no step portions were formed at both ends of the cooling rolls, and the linear pressure at the end of the sheet-like thermoplastic resin composition was not substantially 0 kgf/cm, so the thermoplastic obtained in each comparative example was not The thickness precision of MD of the resin film was 3.0 to 9.9 %, the thickness precision of TD was 1.6 to 6.6 %, and the thickness precision was low.

This application claims the priority on the basis of Japanese Patent Application No. 2011-129128 for which it applied in Japan on June 9, 2011, The content is all used by referring in this specification.

1: Extruder
2: die
3: Molten thermoplastic resin material (or composition)
4, 5: cooling roll
7: axis roll
8: metal thin film
9: fluid
10: step part
11: central part

Claims (7)

A method for producing a thermoplastic resin film in which a sheet-like molten thermoplastic resin material extruded from a die is sandwiched between two cooling rolls and molded, comprising:
On the outer peripheral surface of both ends of at least one of the two cooling rolls, step portions having an outer diameter smaller than the outer diameter of the central portion of the roll are formed circumferentially, respectively,
The thickness of the produced thermoplastic resin film is 0.02-0.5 mm,
The step portion is a step of 0.005 to 0.5 mm,
The step is, with respect to the average thickness of the thermoplastic resin film, the following formula:
0.1T ＜ S ＜ 2.0T
(In the formula, S represents the step, and T represents the average thickness of the thermoplastic resin film)
satisfied with
When the molten thermoplastic resin material is sandwiched between the two cooling rolls, it is also sandwiched between the step portion and the other cooling roll, and the linear pressure that the molten thermoplastic resin material receives between the step portion and the other cooling roll is 0 kgf /cm A method for producing a thermoplastic resin film, characterized in that. The method of claim 1,
The width of the step portion is 10 to 200 mm, the method for producing a thermoplastic resin film. 3. The method according to claim 1 or 2,
The method for producing a thermoplastic resin film, wherein the thermoplastic resin material contains at least one thermoplastic resin selected from the group consisting of acrylic resins, polycarbonate resins, styrene resins, and methyl methacrylate-styrene resins. 3. The method according to claim 1 or 2,
A method for producing a thermoplastic resin film, wherein the step portion has a step difference of 0.01 to 0.2 mm. 3. The method according to claim 1 or 2,
The method for producing a thermoplastic resin film, wherein at least one of the two cooling rolls is an elastic roll having a metal thin film on its outer peripheral surface. 3. The method according to claim 1 or 2,
The method for producing a thermoplastic resin film, wherein the thermoplastic resin material contains rubber particles. delete

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