KR20130090812A - Method of manufacturing surface protective film and apparatus for manufacturing film - Google Patents

Abstract

PURPOSE: A method for manufacturing a surface protection film and a manufacturing equipment of the film are provided to obtain a cover protection film which has non-adhesion on one side, which is not easily blocked when the film is being rolled and piled up, and which has with little fish eye distortion. CONSTITUTION: A method for manufacturing a surface protection film comprises a process of obtaining a molten layer (process 1), a process of obtaining a film (process 2) and a process of rolling the film (process 3). The right end of a thermoplastic resin molten layer is adjusted to be located between the right end of a cooling roll for metal materials and the right end of an elastic roll. The left end of the thermoplastic resin molten layer is adjusted to be located between the left end of the cooling roll for metal materials and the left end of the elastic roll.

Description

The manufacturing method of a surface protection film, and the manufacturing apparatus of a film {METHOD OF MANUFACTURING SURFACE PROTECTIVE FILM AND APPARATUS FOR MANUFACTURING FILM}

The present invention has a non-tacky property on one side of the film, is difficult to block when the film is rolled or rolled up in a roll, and a method for producing a surface protective film and a film with less fisheye can be obtained. Relates to a device.

A surface protection film is a film for protecting the surface of a to-be-adhered object by bonding the film to the surface of a to-be-adhered body. The surface protection film needs to be able to peel the film from the adherend without destroying the adherend. Therefore, the surface protection film is requested | required that one surface has non-tackiness. In addition, if there is a fish eye in a surface protection film, a patch scratch may arise in a to-be-adhered object by affixing the film with a to-be-adhered thing, or it may be misdetected at the time of the foreign material inspection of the to-be-adhered object which bonded the film, There is a need for a surface protective film with less fisheye.

As a method of obtaining a film with few fish-eyes, for example, Patent Document 1 describes the width of the thermoplastic resin molten film in the portion to be pinched when the thermoplastic resin molten film is pinched with a specific metal cooling roll and a specific elastic roll. A method of narrowing the thermoplastic resin molten film by adjusting it to be smaller than the surface length of the metal cooling roll and larger than the surface length of the elastic roll is described.

Japanese Unexamined Patent Publication No. 2011-173415

However, in the method of patent document 1, the film could not be manufactured using the thermoplastic resin with a large neck in. Specifically, since the width of the molten film becomes narrower than the width of the elastic roll, the elastic roll and the metal cooling roll are in direct contact with each other, or in order to interpose a portion having a large thickness at both ends of the molten film called the edge bead part with the elastic roll and the metal cooling roll. Sufficient pressurization was not applied to the center portion of the molten film, and the film could not be produced stably.

Under such circumstances, the problem of the present invention is that even if the resin has a large neck-in, it has a non-tackiness on one side of the film, it is difficult to block when the film is rolled or rolled up in a roll, and a film with few fish eyes is obtained. It is providing the manufacturing method of the surface protection film which can be used, and the manufacturing apparatus of a film.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining, the present inventors discovered that this invention could solve the said subject, and came to complete this invention.

That is, the 1st aspect of this invention is a manufacturing method of a surface protection film, Comprising: The process of obtaining a thermoplastic resin molten film by melt-extruding a thermoplastic resin from a T die (process 1),

The thermoplastic resin molten film is pinched with a metal cooling roll that satisfies all of the following requirements (1) and (2), and an elastic roll that satisfies all of the following requirements (3) and (4), and the pressure is applied. When performing, the process (step 2) of obtaining a film, performing adjustment which satisfy | fills following requirement (5),

And a method for producing a surface protective film having a thickness of 25 to 100 µm having a step (step 3) of winding the film.

Requirement (1): The surface roughness of the surface of the metal cooling roll should be 2.0 µm or more at the maximum height (Rmax).

Requirement (2): The internal temperature of the metal cooling roll should be 15 ° C or higher and the crystallization temperature of the thermoplastic resin -40 ° C or lower.

Requirement (3): The surface of the elastic roll is made of metal and is mirror surface.

Requirement (4): The surface length of the elastic roll is smaller than the surface length of the metal cooling roll.

Requirement (5): Using a positioning member, in the width direction of the thermoplastic resin molten film, the position of the right end of the thermoplastic resin molten film is adjusted between the right end of the metal cooling roll and the right end of the elastic roll, and the thermoplastic Adjust the position of the left end of the resin melt film between the left end of the metal cooling roll and the left end of the elastic roll.

2nd aspect of this invention is a manufacturing method of a surface protection film, Comprising: The process of obtaining a thermoplastic resin molten film by melt-extruding a thermoplastic resin from a T die (process 1),

A process for producing a film by compressing a thermoplastic resin molten film with a metal cooling roll that satisfies both the following requirements (1) and (2) and an elastic roll that satisfies all of the following requirements (3) and (4), In the width direction of the thermoplastic resin molten film, the position of the right end of the thermoplastic resin molten film is between the right end of the metal cooling roll and the right end of the elastic roll, and the position of the left end of the thermoplastic resin molten film is the left end of the metal cooling roll. And pressing the thermoplastic resin molten film with the metal cooling roll and the elastic roll so as to be between the left ends of the elastic roll (step 2-1),

Using the position adjustment member, the position of the right end of the thermoplastic resin molten film is between the right end of the metal cooling roll and the right end of the elastic roll, and the position of the left end of the thermoplastic resin molten film is the left end of the metal cooling roll. Process of pressurizing the thermoplastic resin molten film with the metal cooling roll and the elastic roll while maintaining the state between the left ends of the elastic roll (step 2-2),

And a method for producing a surface protective film having a thickness of 25 to 100 µm having a step (step 3) of winding the film.

Requirement (1): The surface roughness of the surface of the metal cooling roll should be 2.0 µm or more at the maximum height (Rmax).

Requirement (2): The internal temperature control temperature of the metal cooling roll should be 15 degreeC or more and the crystallization temperature of the thermoplastic resin -40 degreeC or less.

Requirement (3): The surface of the elastic roll is made of metal and is mirror surface.

Requirement (4): The surface length of the elastic roll is smaller than the surface length of the metal cooling roll.

The present invention also relates to a T die, a metal cooling roll that satisfies all of the above requirements (1) and (2), an elastic roll that satisfies all of the above requirements (3) and (4), and a T die. It is related with the manufacturing apparatus of the film provided with the positioning member for adjusting the position of the thermoplastic resin molten film melt-extruded from the present invention.

According to this invention, the surface protection film which has a non-tackiness on single side | surface, is difficult to block when winding up or stacking in roll shape, and there is little fish eye can be obtained.

1 is an example of the schematic which shows a part of apparatus which concerns on this invention.
2 is an example of the schematic which shows a part of the apparatus which concerns on this invention seen from the front side of die | dye.
3 is an example of the schematic diagram which shows the contact | adherence state (right end and left end contact | adherence) of the thermoplastic resin molten film and metal cooling roll which concerns on this invention seen along the advancing direction of a thermoplastic resin molten film.
4 is an example of the schematic diagram which shows the close_contact | adherence state (part close to the right end and part close to the left end) of the thermoplastic resin molten film and metal cooling roll which concerns on this invention seen along the advancing direction of a thermoplastic resin molten film.
5 is an example of the schematic diagram which shows the contact | adherence state (full width contact | adherence) of the thermoplastic resin molten film and metal cooling roll which concerns on this invention seen along the advancing direction of a thermoplastic resin molten film.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail.

The manufacturing method of the surface protection film of this invention is a process of obtaining a thermoplastic resin molten film by melt-extruding a thermoplastic resin from a T die (Hereinafter, it may describe as "process 1"), and the thermoplastic resin molten film is described below. When pressure is applied with a metal cooling roll that satisfies all of the requirements (1) and (2), and an elastic roll that satisfies all of the following requirements (3) and (4), the following requirements (5) ), The process of obtaining a film (Hereinafter, it may describe as "process 2"), and the process of winding up the film (process 3).

Requirement (1): The surface roughness of the surface of the metal cooling roll should be 2.0 µm or more at the maximum height (Rmax).

Requirement (2): The internal temperature control temperature of the metal cooling roll should be 15 degreeC or more and the crystallization temperature of the thermoplastic resin -40 degreeC or less.

Requirement (3): The surface of the elastic roll is made of metal and is mirror surface.

Requirement (4): The surface length of the elastic roll is smaller than the surface length of the metal cooling roll.

Requirement (5): Using a positioning member, in the width direction of the thermoplastic resin molten film, the position of the right end of the thermoplastic resin molten film is adjusted between the right end of the metal cooling roll and the right end of the elastic roll, and the thermoplastic The position of the left end of the molten resin film is adjusted between the left end of the metal cooling roll and the left end of the elastic roll.

Step 1 is a step of obtaining a thermoplastic resin molten film having one layer or two or more layers by melt extruding one or two or more thermoplastic resins from a T die.

The thermoplastic resin used in Step 1 is a thermoplastic resin having crystallinity.

Here, "having crystallinity" means that the endothermic peak accompanying melting of a crystal | crystallization is seen in differential scanning calorimetry (DSC). As such resin, Preferably, it is polyolefin resin, More preferably, it is polyethylene resin or polypropylene resin, More preferably, it is polyethylene resin.

Polyethylene-type resin means resin in which content (weight%) of the structural unit derived from ethylene contains 50 weight% or more (however, the total weight of polyethylene-type resin shall be 100 weight%). As polyethylene-type resin, For example, low density polyethylene, ultra low density polyethylene, high density polyethylene, medium density polyethylene, the homopolymer of ethylene, the copolymer of ethylene and the C4-C12 alpha-olefin, the copolymer of ethylene and vinyl acetate And copolymers of ethylene and unsaturated carboxylic acid, copolymers of ethylene and unsaturated carboxylic acid ester, copolymers of ethylene and vinylcyclohexane, and the like. As alpha-olefin, 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methylpentene-1, etc. are mentioned, As an unsaturated carboxylic acid, For example, acrylic acid And methacrylic acid. Examples of the unsaturated carboxylic acid ester include ethyl acrylate, methyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, glycidyl acrylate and methyl meth. Acrylate, ethyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, glycidyl methacrylate and the like. As a copolymer of ethylene and the C4-C12 alpha-olefin, the copolymer of ethylene and 1-butene, the copolymer of ethylene and 1-hexene, the copolymer of ethylene and 1-octene, etc. are mentioned, for example. . Content (weight%) of the structural unit derived from ethylene becomes like this. Preferably it is 60 weight% or more, More preferably, it is 70 weight% or more, More preferably, it is 80 weight% or more.

 As a polypropylene resin, For example, the propylene homopolymer, propylene, the polymer component obtained by superposing | polymerizing the monomer which consists of ethylene and 1 or more types of copolymers of a C4-C12 alpha-olefin, mainly propylene, propylene, The polypropylene type copolymer etc. which are obtained by manufacturing the copolymer component obtained by copolymerizing the monomer which consists of ethylene and / or the C4-C12 alpha-olefin in at least 2 or more stages of multistage are mentioned. As content (weight%) of the structural unit derived from propylene contained in polypropylene resin, Preferably it is 60 weight% or more, More preferably, it is 70 weight% or more, More preferably, it is 80 weight% or more ( However, the total weight of polypropylene resin shall be 100 weight%).

When the thermoplastic resin having a crystallinity used in the present invention is pressurized in the step 2 with a metal cooling roll and an elastic roll, the surface temperature of the metal cooling roll and the elastic roll is lower than the crystallization temperature of the thermoplastic resin. By the crystallization of the thermoplastic resin, the viscosity of the thermoplastic resin becomes high, and film breakage is less likely to occur.

It is preferable that the glass transition temperature (Tg) of a thermoplastic resin is 0 degrees C or less, More preferably, it is -10 degrees C or less. In step 2, the temperature of the roll is usually higher than the temperature at which water condenses on the surface of the roll, or when the cooling roll is cooled by the cooling water, the temperature above the cooling water temperature normally possible with an apparatus such as a cooling water circulation device, that is, 10 It is more than ℃. When the thermoplastic resin molten film is cooled by narrowing the thermoplastic resin molten film with such a metal cooling roll and an elastic roll at such a temperature, if the Tg of the thermoplastic resin is 0 ° C. or less, the thermoplastic resin is hard to recede and troubles such as film breakage are difficult to occur. .

A thermoplastic resin may be used individually by 1 type, and may be used in 2 or more types. 1 type may be sufficient as resin which comprises one layer, and 2 or more types of mixture may be sufficient as it. The method of mixing 2 or more types of thermoplastic resins uses a normal mixing operation, for example, the tumbler blender method, the Henschel mixer method, the Banbury mixer method, the extrusion granulation method, or a metering mixer, and The method etc. which mix in a compounding ratio are mentioned. What is necessary is just to introduce the mixture obtained by these methods into an extruder.

Moreover, a single layer may be sufficient as the film of this invention, or what laminated | stacked several layers may be sufficient. As a method of obtaining the film which laminated | stacked several layers, the film which laminated | stacked 2 or more layers of the layer which consists of thermoplastic resins by coextrusion method can be obtained, for example.

You may mix an additive with the thermoplastic resin used at the process 1 as needed, unless the effect of this invention is impaired. As an additive, antioxidant, a heat stabilizer, a ultraviolet absorber, an antistatic agent, a metal deactivator, etc. are mentioned. From the viewpoint of reducing the amount of remaining adherence to the adherend, the ratio of the additive to the thermoplastic resin is preferably 500 ppm or less, and more preferably 250 ppm or less. The lubricant and the antiblocking agent may be added to such an extent that they do not contaminate or scratch the adherend.

These additives may be in the form of a master batch kneaded in advance with resins such as low density polyethylene, linear low density polyethylene, and polypropylene. There is no restriction | limiting in particular in the kind of base resin of a masterbatch, unless the effect of this invention is impaired.

In process 1, it is preferable to melt-extrude from a T die so that the molten resin temperature in the lip of T die or the molten resin temperature immediately after extrusion from T die may be 200 degreeC or more. Thereby, since the smoothness of the surface of the elastic roll used at the process 2 is easy to be transferred to a thermoplastic resin molten film, and the film surface obtained is easy to be smooth, the adhesiveness at the time of bonding the obtained film to a to-be-adhered object becomes high. The said temperature is more preferably 240 degreeC or more, More preferably, it is 270 degreeC or more. If the molten resin temperature is too high, the molten film of the thermoplastic resin tends to be wound around the mirror-shaped elastic roll having a metal surface or the metal cooling roll with a large sandwiching angle, or the thermal degradation of the thermoplastic resin becomes violent. It is preferable, More preferably, it is 290 degrees C or less.

If a filter such as a wire mesh filter or a metal fiber sintered filter is placed on the breaker plate disposed between the extruder and the T die, and the fish eye or the foreign substance is removed to some extent in advance, the fish eye can easily be crushed when pressing the molten membrane. , desirable. It is particularly advisable to remove large fish eyes as much as possible. Furthermore, it is preferable to arrange | position a leaf disc filter between an extruder and die | dye, and to remove some degree of fish eye or a foreign material previously.

Step 2 is a metal cooling roll (hereinafter may be simply referred to as a "metal cooling roll") that satisfies both the following requirements (1) and (2) of the thermoplastic resin molten film obtained in Step 1, When the pinching is performed with an elastic roll (hereinafter sometimes referred to simply as an "elastic roll") that satisfies both the following requirements (3) and (4), the following requirement (5) is applied. It is a process of obtaining a film, performing a satisfactory adjustment. By the process 2, the thermoplastic resin molten film obtained by the process 1 is solidified by cooling, and a film is obtained.

Requirement (1): The surface roughness of the surface of the metal cooling roll should be 2.0 µm or more at the maximum height (Rmax).

Requirement (2): The internal temperature control temperature of the metal cooling roll should be 15 degreeC or more and the crystallization temperature of the thermoplastic resin -40 degreeC or less.

Requirement (3): The surface of the elastic roll is made of metal and is mirror surface.

Requirement (4): The surface length of the elastic roll is smaller than the surface length of the metal cooling roll.

Requirement (5): Using a positioning member, in the width direction of the thermoplastic resin molten film, the position of the right end of the thermoplastic resin molten film is adjusted between the right end of the metal cooling roll and the right end of the elastic roll, and the thermoplastic The position of the left end of the molten resin film is adjusted between the left end of the metal cooling roll and the left end of the elastic roll.

In this invention, as adjustment in a process 2, before a pinching of a thermoplastic resin molten film with a metal cooling roll and an elastic roll, a positioning member is used, and at least the thermoplastic resin melts in the width direction of the thermoplastic resin molten film. A portion near the right end or the right end of the membrane and a portion near the left end or the left end are brought into close contact with the metal cooling roll, and the position of the right end of the thermoplastic resin molten film in the width direction of the thermoplastic resin molten film is determined by the right end of the metal cooling roll. And the right end of the elastic roll, and it is preferable to adjust the position of the left end of the thermoplastic resin molten film between the left end of the metal cooling roll and the left end of the elastic roll. By adjusting in this way, the neck-in of the thermoplastic resin molten film can be suppressed. When the thermoplastic resin molten film is brought into close contact with the metal cooling roll using the positioning member, the entire width may be brought into close contact with the metal cooling roll in the width direction of the thermoplastic resin molten film. Even after the molten film is pinched by the metal cooling roll and the elastic roll, the position adjusting member closes the right end or the right end of the thermoplastic resin molten film to the left end or the left end of the thermoplastic film in close contact with the metal cooling roll to melt the thermoplastic resin. In the width direction of the membrane, the position of the right end of the thermoplastic resin molten film is adjusted between the right end of the metal cooling roll and the right end of the elastic roll, and the position of the left end of the thermoplastic resin molten film is adjusted to the left end of the metal cooling roll and its It is preferable to manufacture a film, adjusting between the left ends of an elastic roll.

As a position adjustment member, an air nozzle, a vacuum box, and an electrostatic pinning member are mentioned, for example.

In the method using an air nozzle, as shown to FIG. 1 and FIG. 2, the air blown out from two air nozzles provided in the vicinity of the both ends of right and left sides of a thermoplastic resin melt film is sprayed in the both ends of the thermoplastic resin melt film extruded from a T die. Then, the neck-in is suppressed so that the width of the thermoplastic resin molten film becomes wider than the width of the elastic roll by pressing the thermoplastic resin molten film onto the metal cooling roll.

Process 2 may have the following two processes. These two processes are processes of manufacturing a film by pinching a thermoplastic resin molten film with a metal cooling roll and an elastic roll, and the position of the right end of the thermoplastic resin molten film in the width direction of the thermoplastic resin molten film is this metal cooling roll. The thermoplastic resin molten film is formed of the metal cooling roll and the elastic roll so that the position of the left end of the thermoplastic resin molten film is between the left end of the metal cooling roll and the left end of the elastic roll between the right end of the elastic roll and the right end of the elastic roll. Process of pinching (step 2-1),

Using the position adjustment member, the position of the right end of the thermoplastic resin molten film is between the right end of the metal cooling roll and the right end of the elastic roll, and the position of the left end of the thermoplastic resin molten film is the left end of the metal cooling roll. It is a process (process 2-2) which pressurizes the said thermoplastic resin molten film with this metal cooling roll and this elastic roll, maintaining the state between the left ends of the elastic roll (process 2-2).

Although the width | variety of the discharge port of T die | dye is more than the width | variety of an elastic roll, when the width | variety of the molten membrane at the time of pinching a molten film with a metal cooling roll and an elastic roll is narrower than the width of an elastic roll, as a method of using an air nozzle, The following method is mentioned. Until the width of the thermoplastic resin molten film becomes wider than the width of the elastic roll, the take-out speed of the film is sufficiently slowed to suppress neck-in. Thereafter, the thermoplastic resin molten film is pinched with an elastic roll and a metal cooling roll. In the case of a resin having a large neck in, the neck in becomes large in order to increase the speed up to a predetermined take-up speed in this state, and the width of the thermoplastic resin molten film becomes narrower than the width of the elastic roll, and film forming cannot be performed. Therefore, after pinching the molten film, air is blown to both ends of the thermoplastic resin molten film by using an air nozzle to press the molten film against the metal cooling roll to suppress neck in, and the width of the thermoplastic resin molten film becomes wider than the width of the elastic roll. Then, the speed may be increased to a predetermined taking speed.

In addition, when the neck-in resin is larger and the pulling speed of the film is sufficiently slowed, and the width of the thermoplastic resin molten film is still not wider than the width of the elastic roll, air is first applied to both ends of the thermoplastic resin molten film by using an air nozzle. After spraying, the molten film is pressed on the metal cooling roll to suppress neck-in, and the width of the thermoplastic resin molten film is sufficiently wider than the width of the elastic roll, and then the elastic roll is pressed on the molten film to press the molten film thereafter, if necessary. After adjusting the injection of air from the furnace air nozzle, the speed may be increased to a predetermined taking speed.

The surface roughness of the surface of the metal cooling roll used at the process 2 is 2.0 micrometers or more in a maximum height (Rmax), Preferably it is 2.5 micrometers or more, More preferably, it is 4.5 micrometers or more. When the surface roughness of the surface uses a metal cooling roll having a maximum height Rmax of 2.0 µm or more, the surface of the metal cooling roll is transferred to one side of the thermoplastic resin molten film, and the thermoplastic resin melted on the side in contact with the metal cooling roll. By roughening the surface of a film moderately, the film hard to block is obtained. Such metal cooling rolls generally include what are called easy rolls, semi-matrols, and matrols.

When the obtained film is wound in step 3, the surface on which the film is roughened and the surface not roughened overlap with each other. If the roughness of the film surface to which the surface of the metal cooling roll was transferred is too big | large, a flaw may arise easily in the film surface without surface roughness which contacts the surface. Moreover, when using the film obtained by the method of this invention in order to protect the surface of film-like objects, such as an optical film, the film is bonded together so that the film surface formed by contacting an elastic roll whose surface is a mirror surface may contact an adherend. When the optical film on which the surface protection film is bonded is wound or superimposed, the film surface on which the surface roughness of the metal cooling roll is transferred is in contact with the surface on which the surface protection film is not bonded, such as an optical film, which is an adherend. Therefore, there exists a possibility that a scratch may arise easily on the surfaces, such as an optical film. In order to make it difficult to produce such a problem, the surface roughness of the surface of the metal cooling roll is preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 6 μm or less as the maximum height Rmax. . In addition, the maximum height Rmax is prescribed | regulated to JIS BO601-1982.

If the metal material of the metal cooling roll used at the process 2 is generally used for the cooling roll of a film processing machine, there will be no restriction | limiting in particular, For example, carbon steel, stainless steel, etc. are mentioned, Hard chromium plating process is carried out to these, for example. It is preferable to carry out. In view of cooling efficiency, the surface material of the cooling roll is preferably made of metal.

The internal temperature control temperature of the metal cooling roll used at the process 2 is 15 degreeC or more and crystallization temperature of a thermoplastic resin -40 degreeC or less. The internal temperature control temperature of the metal cooling roll can be adjusted by flowing a cooling medium such as water or oil into the roll. The internal temperature control temperature is a temperature of a cooling medium such as water flowing in the inlet pipe just before being introduced into the metal cooling roll. For example, a thermometer or a temperature sensor is installed in the inlet pipe to provide a The temperature of the cooling medium flowing through can be measured. By setting the internal temperature control temperature of the metal cooling roll to the crystallization temperature of the thermoplastic resin at -40 ° C or less, when the thermoplastic resin molten film is pinched by the metal cooling roll and the elastic roll, the molten film is cooled to such an extent that the elasticity of the thermoplastic resin has a sufficient size. Therefore, the film becomes difficult to break. On the other hand, when the internal temperature control temperature of a metal cooling roll is higher than the crystallization temperature of -40 degreeC of a thermoplastic resin, what is called roll separation defect which may become difficult to separate a thermoplastic resin molten film from a metal cooling roll may arise. When the internal temperature control temperature of a metal cooling roll is lower than 15 degreeC, the surface shape of a metal cooling roll may not be fully transferred to a thermoplastic resin molten film, and the film obtained may block. Moreover, depending on the environment at the time of film processing, there exists a possibility that the metal cooling roll may condensate, and it is unpreferable.

Crystallization temperature is a temperature which shows the exothermic peak at the time of temperature-falling, for example using a differential scanning calorimeter, after heating up to melting | fusing point of resin or more.

The surface of the elastic roll used at the process 2 is metal, and the surface is a mirror surface. Here, "the surface of an elastic roll is a mirror surface" means that the surface roughness of the surface of an elastic roll is 0.5 micrometer or less in maximum height (Rmax), Preferably it is 0.3 micrometers or less, More preferably, it is 0.2 micrometer or less. . When the elastic roll whose surface is a mirror surface is used, the smoothness of the film surface to manufacture will become high, and when sticking to a to-be-adhered body as a film, it will become easy to adhere | attach, ie, the non-adhesive effect is acquired.

When the surface roughness of the surface of the elastic roll exceeds 0.5 µm at the maximum height Rmax, the smoothness of the surface to which the adherend is bonded is poor, and the adhesiveness tends to decrease. As maximum height Rmax, Preferably it is 0.01-0.5 micrometer.

The surface of the elastic roll used at the process 2 is metal. An elastic material may be bonded to the inner surface, or a rubber roll that is in contact with only the portion of the metal thin sleeve that is in contact with the sleeve and the portion that narrows the film at the time of film production, instead of contacting the entire circumference of the inner surface of the sleeve. Exists, and cooling water, water for heating, oil, etc. may exist in the clearance gap between a thin metal sleeve and a rubber roll. As a metal, what was hard chrome plated with nickel etc. is mentioned, for example. As an elastic body, rubber | gum etc. are mentioned, for example. Examples of the elastic rolls used in Step 2 include flex rolls (trade name: manufactured by Sumitomo Heavy Machinery Modern Co., Ltd.), TES rolls (trade name: manufactured by Toshiba Machinery Co., Ltd.), UF rolls (trade name: manufactured by Hitachi Shipbuilding Co., Ltd.), and the like. Can be. In particular, when the part of the width direction of the roll including the part which clamps the molten film in the elastic roll is elastically deformable to both ends of the roll, the roll may be elastically deformed in the entire width direction of the roll. Such a roll is preferable to press the fish eye more easily and to crush it.

If the surface is not made of metal but the surface is made of an elastic body such as rubber, the elastic force of the elastic body is inherent in accordance with the material used. Therefore, when the surface pressure on the thermoplastic resin melt film is changed, other surface materials are different. It is necessary to replace the elastic body every time it takes time. On the other hand, when the surface uses the roll which is a metal material, the surface pressure with respect to a thermoplastic resin molten film may be changed only by changing the supply pressure of cooling fluids, such as water, which exists in the inside of a roll. . In addition, the surface of the metal is easier to press the fish eye than the rubber. In addition, in the rubber roll, the temperature control of the surface is not necessarily easy, but in the elastic roll whose surface is metal, since the thermal conductivity of metal is large, it is easy to adjust roll temperature by water passing inside.

As a method of processing the surface roughness of the metal cooling roll used in the process 2 and the elastic roll to a predetermined roughness, a well-known surface finishing method, such as buffing polishing, can be used, for example.

The internal temperature control temperature of the elastic roll used in the process 2 can be adjusted by flowing cooling media, such as water and oil, in a roll. The internal temperature control temperature of the elastic roll is a temperature of a cooling medium such as water flowing in the inlet pipe just before being introduced into the elastic roll. For example, a thermometer or a temperature sensor is provided in the inlet pipe. The temperature of the cooling medium flowing in the pipe can be measured. It is preferable that the internal temperature control temperature of an elastic roll is 10 degreeC or more. If the temperature is too low, condensation easily occurs. Moreover, since the molten film | membrane becomes easy to wind around a roll in the internal temperature control temperature of an elastic roll more than the crystallization temperature of a thermoplastic resin, it is preferable to make it lower than a crystallization temperature.

If the surface length of the metal cooling roll used at the process 2 is not larger than the width | variety of a thermoplastic resin molten film, since a molten film will return to the side surface of a metal cooling roll, film forming becomes difficult. Moreover, when the surface length of an elastic roll is wider than the width | variety of a thermoplastic resin melt film, the both ends of an elastic roll will directly contact a metal cooling roll, and a roll will be damaged. Therefore, it is necessary to adjust the neck-in width of the thermoplastic resin molten film so that the width of the thermoplastic resin molten film becomes larger than the width of the elastic roll. The adjustment of the neck in may be performed by appropriately selecting the temperature of the molten resin, the pulling speed of the thermoplastic resin molten film, the air gap, and the like. Nevertheless, when the width of the thermoplastic resin melt film is smaller than the width of the elastic roll, the air gap can be shortened by using a vacuum box (or vacuum chamber) in combination and adhering the thermoplastic resin melt film to the metal cooling roll to adsorb it. Alternatively, the air is blown to an end portion or both ends of the thermoplastic resin molten film by using an air nozzle, or by using an electrostatic pinning member, at least both ends or portions near the both ends of the thermoplastic resin molten film are pressed against the metal cooling rolls to be in close contact with each other. Can be suppressed. Here, the portions close to both ends may not necessarily be the most end portions of the thermoplastic resin molten film. For example, the ends of the thermoplastic resin molten film are not in close contact with the metal cooling roll, but for example, from the ends of the thermoplastic resin molten film, The state in which any part in the range from the center about 2 to 3 cm in the horizontal direction is in close contact with the metal cooling roll may be sufficient. Moreover, if the part near the both ends or both ends of a thermoplastic resin melt film is in close_contact | adherence, the other part of the width direction of a melt film may be in close contact with a metal cooling roll, and does not need to be in close_contact | adherence, It is preferable to be in close contact with the roll. In this way, the width of the thermoplastic resin molten film can be made larger than the width of the elastic roll by suppressing the neck-in of the thermoplastic resin molten film. When the pulling-in speed of the film is slowed down to reduce the neck-in, and after the thermoplastic resin molten film is pressed on the metal cooling roll by the elastic roll, the speed is increased and the neck-in becomes large when the speed is increased to a predetermined pulling-up speed. When the width | variety of a thermoplastic resin molten film becomes smaller than the width | variety of an elastic roll, after pinching a molten film at low speed, neck in can be suppressed using a vacuum box, an air nozzle, or an electrostatic pinning member as mentioned above. Moreover, from these, the surface length of an elastic roll needs to be smaller than the surface length of a metal cooling roll. Surface length means here the length of the width direction of the roll designed as a part which the molten film extruded from the die contacts among the structure of a roll. Moreover, in order to carry out film forming stably, it is preferable to make thickness distribution of the width direction of a thermoplastic resin molten film and a flow direction as small as possible. Moreover, it is preferable that an elastic roll does not contact with the edge bead part of both ends of a thermoplastic resin molten film as much as possible.

The pinching pressure in the process 2 is a metal cooling roll and the said elastic roll through a thermoplastic resin molten film extruded from the T die which passes between these rolls.

As a method of pinching at least 1 layer or more of thermoplastic resin molten films obtained by the said process by the said metal cooling roll and the said elastic roll, for example, the position of the said metal cooling roll is fixed, the said elastic roll is moved, and it melt | dissolves A method of pressing the film on a metal cooling roll, a method of fixing the position of the elastic roll, and a method of moving the metal cooling roll to press the molten film on the elastic roll, and preferably, fixing the position of the metal cooling roll. And the elastic roll is moved to press the molten film on the metal cooling roll. The pressure at the time of pressing a molten film should just be more than the pressure which a thermoplastic resin molten film adheres completely to the said metal cooling roll, and may adjust suitably according to the melt viscosity of a thermoplastic resin molten film, the thickness of a thermoplastic resin molten film, etc.

By pressurizing the thermoplastic resin molten film obtained by process 1 with the said metal cooling roll and the said elastic roll in process 2, the thermoplastic resin molten film is solidified by cooling and a film is obtained. At this time, one side of the thermoplastic resin molten film which contacted the said elastic roll becomes smooth, and the surface expresses non-tackiness. In addition, since the surface of the metal cooling roll is transferred to one side of the thermoplastic resin molten film in contact with the metal cooling roll, the one side of the resulting film becomes difficult to block, and the film is easy to slip during film processing. It becomes easy to wind up a film neatly. Moreover, since blocking of films is also reduced, when a film is wound up, a film becomes easy to loosen. In addition, since the fish eye is pressed and crushed by pinching, and the film surface of the fish eye presence portion is not swelled and smoothed, the adherend is damaged by the swelling portion of the fish eye even when the film is bonded to the adherend. none.

Step 3 is a step of winding up the film obtained in step 2. As a method of winding up a film, you may wind up by a normal method, such as winding up a film with a winder.

The thickness of the film manufactured by this invention is 25-100 micrometers, Preferably it is 30 micrometers-70 micrometers.

The film obtained by the manufacturing method of this invention is used as a surface protection film.

For example, a resin plate and a metal plate; Members for flat panel displays (FPD) such as base glass for liquid crystal displays, polarizing films for liquid crystal displays, retardation films, and light diffusion sheets; Films constituting optical discs such as Blu-ray discs and DVDs; It is preferably used as a surface protection film for protecting the surface of such a back.

Moreover, the manufacturing apparatus of the film of this invention is a T die, the metal cooling roll which satisfy | fills all the following requirements (1) and requirements (2), and the elasticity which satisfies all the following requirements (3) and requirements (4). A roll and a positioning member for adjusting the position of the thermoplastic resin molten film melt-extruded from a T die are provided.

Requirement (1): The surface roughness of the surface of the metal cooling roll should be 2.0 µm or more at the maximum height (Rmax).

Requirement (2): The internal temperature control temperature of the metal cooling roll should be 15 degreeC or more and the crystallization temperature of the thermoplastic resin -40 degreeC or less.

Requirement (3): The surface of the elastic roll is made of metal and is mirror surface.

Requirement (4): The surface length of the elastic roll is smaller than the surface length of the metal cooling roll.

(Example)

Hereinafter, the present invention will be described on the basis of examples.

[Measurement Method]

The physical property in an Example was measured by the following method.

(1) blocking strength

It carried out as follows by the vertical blocking method. The film obtained by the method of Example 1 mentioned later was cut out to the magnitude | size of 225 mm x 100 mm. The sample which cut out the two sheets of films cut out and contacted with the elastic roll was prepared. The sample was kept at 23 ° C. for 30 minutes in the presence of a 3 kg load. The sample is mounted on a jig so that the contact area of the two overlapping films becomes 100 cm 2 so as to be peeled off in the direction perpendicular to the film surface (up and down direction) to the Toyo Sekiyobo tester up and down blocking system, and 20 g from a close state. Two films were peeled off at the constant peeling rate of / min. The load when the upper and lower jig was opened was read, and it was set as blocking strength.

The sample which laminated | stacked the other two sheets cut out so that the surface formed in contact with the elastic roll of one film and the surface formed by contacting with the metal cooling roll of the other film was prepared, and the blocking strength was calculated | required by the above-mentioned method.

(2) confirmation of fish eye

The fish eye shape in the film in the Example was confirmed as follows.

The shape observation of the fish eye (FE) part and the height (protrusion height) of the swelling of the film surface of the fish eye part were measured using the Kiens super depth shape measurement microscope VK-8500. The protrusion height measured 5 points | pieces about the FE part of the side which contacted the elastic roll surface of the film, and calculated | required the average value. In addition, the protrusion height here is the height of the highest part of the part which swelled in the area | region which swelled in the area | region over several tens of micrometers-several mm as size in a film plane by presence of an FE nucleus, Fine irregularities are not included. Therefore, when the molten film is pinched by the metal cooling roll and the elastic roll, the surface shape of the metal cooling roll is transferred to the film surface formed in contact with the metal cooling roll of the film. On the basis of the size (width of the acid) in the in-plane direction of the film per unevenness, a small scale of several micrometers to 20 micrometers is large and fine irregularities of about 3 micrometers in height are confirmed, which is the roughness of the film surface itself, and the FE It is not covered because it is not a projection based on the existence of.

Example 1

[Suzy]

Sumikasen E FV403, which is a linear low density polyethylene manufactured by Japan Evo Industries Co., Ltd. and sold by Sumitomo Chemical Co., Ltd., was used. The crystallization temperature was 103.6 ° C. The crystallization temperature was set using a differential scanning calorimeter (PYRIS Diamond DSC, manufactured by Perkin Elmer), and after the sample was set at 24 ° C, the temperature was raised to 150 ° C at 200 ° C / min, held at 150 ° C for 5 minutes, and then up to 20 ° C. It was set as the temperature which shows the exothermic peak at the time of temperature-falling at 5 degree-C / min. Crystallization temperature -40 degreeC is 63.6 degreeC.

[Cold Cooling Roll]

A cold roll made of hard chromium-plated steel having a surface length of 650 mm and a surface roughness of 4.5 µm at Rmax with a surface of an easy phase was used. The internal temperature control temperature of the cooling roll was set to 30 ° C.

[Elastic roll]

An elastic roll having a surface length of 430 mm and having a rubber portion inside the roll and having a surface roughness of 0.2 S on a mirror surface having a hard chromium-plated nickel was used.

The elastic roll was included in both ends, and what was elastically deformable in the whole surface length was used. The internal temperature control temperature of the elastic roll was set to 15 ° C.

[Making of film]

Using a total of three extruders, one of φ 50 mm extruder and two φ 40 mm extruder manufactured by Sumitomo Heavy Machinery Modern Co., Ltd., a die temperature of 240 ° C. and a screw rotation speed of 29 revolutions per minute from a T die having an effective width of 600 mm. The resin was extruded by.

The extruded molten resin was wound around a metal cooling roll, the film was taken out at a take-up speed of 5 m / min, and wound up by a winder. At this take-up speed, the width of the molten film was larger than the width of the elastic roll, so that the position of the right end of the molten film in the width direction of the molten film is between the right end of the metal cooling roll and the right end of the elastic roll. The molten film was pinched by the cooling roll and the elastic roll so that the position of the left end of the molten film was between the left end of the metal cooling roll and the left end of the elastic roll. In this state, air was sprayed on both ends of the molten film by using an air nozzle, the neck in was suppressed by pressing the molten film on a metal cooling roll, and the width of the molten film was expanded. After that, the take-up speed was gradually increased. The film thickness became 30 micrometers when the take-up speed was 35 m / min. The film was produced by maintaining the film production conditions when the take-up speed was 35 m / min.

The film was wound up while trimming film both ends, and the film of 1 type 3 layer of width 300mm and thickness 30micrometer was obtained. The die was in a clean room and the molten resin was extruded and wound in the clean room. The extruder is installed outside the clean room and a feed pipe connecting the extruder and the die penetrates the walls of the clean room. The wire mesh filter was arranged in the breaker plate in the order of 80 mesh, 120 mesh, and 80 mesh from the upstream side to the downstream side. Table 1 shows measurement results of protrusion height and physical properties of the fish eye portion of the obtained film. The blocking strength of the surfaces formed in contact with the elastic roll was 39 N / m 2, and non-tackiness was expressed. The blocking strength of the surface formed in contact with the elastic roll and the surface formed in contact with the metal cooling roll was almost zero and hardly blocked. The protrusion height of the fish eye portion of the film surface formed in contact with the elastic roll was 1.1 µm, and the fish eye was almost pressed and crushed by pinching. The film surface formed in contact with the metal cooling roll was almost smooth.

Comparative Example 1

Except not using an air nozzle, the same procedure as in Example 1 was carried out, but as a result of gradually increasing the take-out speed from 5 m / min, the neck in was large, and the width of the molten film was 11 m / min. As it became small, it returned immediately to 10m / min. The film thickness at 10 m / min was 115 micrometers, and in the step of adjusting thickness to 30-100 micrometers which is the thickness of a general surface protection film, a problem arises and it was not able to make it the thickness required as a product itself.

1: T die
2: metal cooling roll
3: elastic roll
4: film
5: air nozzle
6: thermoplastic resin melt film

Claims (7)

As a manufacturing method of a surface protection film, The process of obtaining a thermoplastic resin molten film by melt-extruding a thermoplastic resin from a T die (process 1),
The thermoplastic resin molten film is pinched with a metal cooling roll that satisfies all of the following requirements (1) and (2), and an elastic roll that satisfies all of the following requirements (3) and (4), and the pressure is applied. When performing, the process (step 2) of obtaining a film, performing adjustment which satisfy | fills following requirement (5),
And a method for producing a surface protective film having a thickness of 25 to 100 µm having a step (step 3) of winding up the film.
Requirement (1): The surface roughness of the surface of the metal cooling roll should be 2.0 µm or more at the maximum height (Rmax).
Requirement (2): The internal temperature control temperature of the metal cooling roll should be 15 degreeC or more and the crystallization temperature of the thermoplastic resin -40 degreeC or less.
Requirement (3): The surface of the elastic roll is made of metal and is mirror surface.
Requirement (4): The surface length of the elastic roll is smaller than the surface length of the metal cooling roll.
Requirement (5): Using a positioning member, in the width direction of the thermoplastic resin molten film, the position of the right end of the thermoplastic resin molten film is adjusted between the right end of the metal cooling roll and the right end of the elastic roll, and the thermoplastic The position of the left end of the molten resin film is adjusted between the left end of the metal cooling roll and the left end of the elastic roll. The method of claim 1,
The said requirement (5) uses the position adjustment member, and at least the part near the right end or the right end of the thermoplastic resin melt film, and the part near the left end or the left end to the metal cooling roll in the width direction of the thermoplastic resin melt film In the width direction of the thermoplastic resin molten film, the position of the right end of the thermoplastic resin molten film is adjusted between the right end of the metal cooling roll and the right end of the elastic roll, and the position of the left end of the thermoplastic resin molten film It adjusts between the left end of a metal cooling roll, and the left end of the elastic roll, The manufacturing method of the surface protection film characterized by the above-mentioned. As a manufacturing method of a surface protection film, The process of obtaining a thermoplastic resin molten film by melt-extruding a thermoplastic resin from a T die (process 1),
A process for producing a film by compressing a thermoplastic resin molten film with a metal cooling roll that satisfies both the following requirements (1) and (2) and an elastic roll that satisfies all of the following requirements (3) and (4), In the width direction of the thermoplastic resin molten film, the position of the right end of the thermoplastic resin molten film is the position of the left end of the thermoplastic resin molten film between the right end of the metal cooling roll and the right end of the elastic roll. Pressing the thermoplastic resin molten film with the metal cooling roll and the elastic roll so as to be between the left end and the left end of the elastic roll (step 2-1),
Using the position adjustment member, the position of the right end of the thermoplastic resin molten film is between the right end of the metal cooling roll and the right end of the elastic roll, and the position of the left end of the thermoplastic resin molten film is the left end of the metal cooling roll. Process of pressurizing the thermoplastic resin molten film with the metal cooling roll and the elastic roll while maintaining the state between the left ends of the elastic roll (step 2-2);
And a method for producing a surface protective film having a thickness of 25 to 100 µm having a step (step 3) of winding up the film.
Requirement (1): The surface roughness of the surface of the metal cooling roll should be 2.0 µm or more at the maximum height (Rmax).
Requirement (2): The internal temperature control temperature of the metal cooling roll should be 15 degreeC or more and the crystallization temperature of the thermoplastic resin -40 degreeC or less.
Requirement (3): The surface of the elastic roll is made of metal and is mirror surface.
Requirement (4): The surface length of the elastic roll is smaller than the surface length of the metal cooling roll. The method of claim 3, wherein
The said process (2-2) uses the positioning member, and the metal cooling roll is a part near the right end or the right end, and the left end or the left end of the thermoplastic resin molten film at least in the width direction of the thermoplastic resin molten film. In close contact, the position of the right end of the thermoplastic resin molten film is between the right end of the metal cooling roll and the right end of the elastic roll, and the position of the left end of the thermoplastic resin molten film is the left end of the metal cooling roll and the elastic roll. A method of producing a surface protection film, the method comprising: pressing the thermoplastic resin molten film with the metal cooling roll and the elastic roll while manufacturing a film while maintaining a state between the left ends. The method according to claim 1 or 3,
The manufacturing method of the surface protection film whose position adjustment member is an air nozzle, a vacuum box, or an electrostatic pinning member. A T die, a metal cooling roll that satisfies all of the following requirements (1) and (2), an elastic roll that satisfies all of the following requirements (3) and (4), and a thermoplastic resin melt-extruded from the T die. The manufacturing apparatus of the film provided with the positioning member for adjusting the position of a molten film.
Requirement (1): The surface roughness of the surface of the metal cooling roll should be 2.0 µm or more at the maximum height (Rmax).
Requirement (2): The internal temperature control temperature of the metal cooling roll should be 15 degreeC or more and the crystallization temperature of the thermoplastic resin -40 degreeC or less.
Requirement (3): The surface of the elastic roll is made of metal and is mirror surface.
Requirement (4): The surface length of the elastic roll is smaller than the surface length of the metal cooling roll. The method according to claim 6,
The manufacturing apparatus of the film whose position adjusting member is an air nozzle, a vacuum box, or an electrostatic pinning member.

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