KR20160031249A - Multi-layered film and a manufacturing method for the same - Google Patents

Abstract

The present invention relates to a method for manufacturing a multi-layered film which, more specifically, is manufactured by using polycarbonate and polymethyl methacrylate as main materials to be extruded and laminated at the same time without use of an adhesive. The multi-layered film comprises: a core layer made of a polycarbonate (PC) resin; a first skin layer made of a polymethylmethacrylate (PMMA) resin on one side of the core layer; and a second skin layer made of the polymethylmethacrylate (PMMA) resin on the other side of the core layer. The method for manufacturing a multi-layered film includes: a first step of drying the PC resin and the PMMA resin; a second step of storing the PC resin in a first hopper unit; a third step of storing the PMMA resin in a second hopper unit; a fourth step of manufacturing a sheet by co-extruding the PC resin in the hopper unit and the PMMA resin in the second hopper unit by using a T-die; a fifth step of processing the sheet into a film by using the T-die; a sixth step of calendar-processing the film; a seventh step of treating the surface of the calendar-processed film; and an eighth step of removing impurities from the surface-treated film.

Description

MULTI-LAYERED FILM AND A MANUFACTURING METHOD FOR THE SAME [0002]

The present invention relates to a multilayer film and a method for producing the multilayer film, and more particularly, to a multilayer film which is produced by using polycarbonate and polymethyl methacrylate as main materials and capable of lamination at the same time as extrusion without using an adhesive, and a method for producing the same.

Polycarbonate is excellent in oxygen barrier property and transparency, but it has a disadvantage that it is difficult to use as a single film due to its low glass transition temperature (Tg). In most cases, it should be laminated with another resin.

Therefore, in order to laminate a polycarbonate with a resin such as polyethylene (PE) or polypropylene (PP), an appropriate adhesive capable of bonding a resin should be used. However, when an adhesive is used, the thickness of the film becomes thick, and there is a problem that delamination may occur between the polycarbonate and the resin.

Korean Patent Laid-Open No. 10-2013-0003435 An optical film having improved hardness

SUMMARY OF THE INVENTION The present invention has been conceived in order to solve the above problems, and it is an object of the present invention to provide a method for manufacturing a multilayered film, in which a film is not adhered using an adhesive agent but a molten resin is injected into a T- It is an object of the present invention to provide a multilayered film production method capable of producing a multilayered film without need for a separate adhesive so as to be laminated.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention as set forth in the accompanying drawings. It will be possible.

In order to achieve the above object, the present invention provides a multilayer film comprising: a center layer made of polycarbonate (PC) resin; A first skin layer made of polymethylmethacrylate (PMMA) resin on one side of the center layer; And a second skin layer made of polymethylmethacrylate (PMMA) resin on the other side of the center layer.

The present invention also provides a method for manufacturing a multilayer film, comprising: a first step of drying a polycarbonate (PC) resin and a polymethyl methacrylate (PMMA) resin; A second step of storing the polycarbonate (PC) resin in a first hopper part; A third step of storing the polymethyl methacrylate (PMMA) resin in a second hopper part; A fourth step of co-extruding the polycarbonate resin of the first hopper portion and the polymethylmethacrylate resin of the second hopper portion using a tie to produce a sheet; A fifth step of producing the sheet in a film form through a titania; A sixth step of calendering the film; A seventh step of surface-treating the calendered film; And removing the foreign substances from the surface-treated film.

The multilayer film of the present invention and its manufacturing method have the following effects.

The multilayer film of the present invention and its production method can be used in a toluene solvent and can produce a multilayer film having excellent optical properties by forming a multilayer film by laminating polymethylmethacrylate on polycarbonate having weak solvent resistance on the upper and lower surfaces There is an effect.

In addition, the multilayered film of the present invention and the method of manufacturing the same can be applied not only to adhesion of a weakly adherent polycarbonate film to a polymethylmethacrylate film, but also to a method of extruding a molten polycarbonate resin and a polymethylacrylate resin By adjusting the temperature, the adhesive force can be improved to enable lamination at the same time as extrusion, so that it is possible to produce a thinner multilayer film without any additional adhesive.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side cross-sectional view showing the configuration of a preferred embodiment of the multilayer film of the present invention. Fig.
2 is a flow chart showing a method for producing a multilayer film of the present invention.

The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings.

As shown in Fig. 1, the multilayer film of the present invention comprises a center layer 2 made of polycarbonate (PC) resin, a first skin layer made of polymethyl methacrylate (PMMA) resin on one side of the center layer 1) and a second skin layer 3 made of polymethyl methacrylate (PMMA) resin on the other side of the center layer.

The center layer 2 as a base of the multilayer film is made of polycarbonate (PC) resin.

The polycarbonate (PC) resin is suitable for performing the role as the center layer 2 serving as the base of the film due to the advantages of excellent transparency and impact resistance.

The first skin layer 1 and the second skin layer 3 constituting the multilayer film are made of polymethylmethacrylate (PMMA) resin.

In order to compensate the chemical resistance of the polycarbonate which is the center layer 2, the multilayer film is formed by coating a first skin layer 1 and a second skin layer 3 made of polymethyl methacrylate on both sides of the center layer, Thereby improving the chemical resistance of the film.

The thickness of the multilayered film is preferably 15 to 100 mu m. If the thickness of the multilayer film is less than 15 mu m, the mechanical strength of the film may be lowered. If the thickness of the multilayer film exceeds 100 mu m, the transparency may decrease.

The multilayered film production method of the present invention is produced by coating and laminating polymethyl methacrylate on the upper and lower surfaces of a polycarbonate film using a T-die method in a co-extrusion method.

The co-extrusion method is a method of forming a composite film by laminating a plurality of layers in a molten state such that each molten resin is simultaneously extruded by using two or more extruders. The extruder is a tubular method and a T-die, It is divided into laws.

In the method for producing a multilayer film of the present invention, a multilayer film is produced by an in-die bonding method using a T-die method.

≪ Method for producing multilayer film &

Fig. 2 is a view for explaining a method for producing a multilayer film of the present invention.

First, polymethyl methacrylate (PMMA) resin and polycarbonate (PC) resin are dried in the first step S10. Specifically, a polymethyl methacrylate (PMMA) resin and a polycarbonate (PC) resin used as a main material of the multilayer film are dried in a drying section.

The drying step is performed in order to increase the adhesion force between the resins and to prevent the film from being defective.

Next, in the second step S20, a polycarbonate (PC) resin is stored in the first hopper. Specifically, a polycarbonate resin serving as a raw material of the center layer is stored in the first hopper portion.

Next, in the third step S30, a polymethyl methacrylate (PMMA) resin is stored in the second hopper. Specifically, a polymethyl methacrylate (PMMA) resin serving as a raw material for the first and second skin layers is stored in the second hopper portion.

Next, in a fourth step (S40), a polycarbonate resin in the first hopper portion and a polymethylmethacrylate resin in the second hopper portion are co-extruded to produce a sheet. Specifically, the polycarbonate resin supplied from the first hopper portion and the polymethylmethacrylate resin supplied from the second hopper portion are melt-extruded through a screw cylinder, and then formed into a sheet form using a feed block.

The co-extrusion process in the fourth step may be divided into steps 4-1 to 4-4 as follows.

First, in Step 4-1 (S41), the polycarbonate resin in the first hopper portion is extruded. Specifically, the polycarbonate resin in the first hopper portion is melt-extruded using a screw cylinder to produce a sheet.

Next, in step 4-2 (S42), the polymethyl methacrylate resin in the second hopper part is extruded. Specifically, the polymethyl methacrylate resin of the second hopper portion is melt-extruded using a screw cylinder to produce a sheet.

Next, in Step 4-3 (S43), a polycarbonate (PC) sheet extruded in a feed block is used as a center layer, a polymethyl methacrylate (PMMA) sheet is used as a first skin layer, 2 skin layer to prepare a multilayer sheet. Specifically, a multilayer sheet is prepared by using a polycarbonate sheet as a center layer and a polymethylmethacrylate sheet as a first skin layer and a second skin layer on both sides thereof in a shape of a multilayer sheet in a feed block.

In the co-extrusion process in the fourth step, temperature control is an important factor for improving the adhesion of the multilayered film, which is a thermally adhesive resin.

The temperature control in the co-extrusion process divides the total section into 5 to 12 sections and sequentially changes the temperature to improve the adhesion between the sheets.

Specifically, the total section of the co-extrusion process includes a first section connected to the hopper section, a second section beginning the cylinder section, and a section that is melt-extruded up to the cylinder section and the feed block is divided into 3 to 9 sections, 5 to 12 periods including 5 to 12 periods.

First, the resin is supplied at 260 to 320 ° C in the first section connected to the hopper section.

If the temperature of the first section is lower than 260 ° C, melting of the resin may not be performed smoothly, resulting in problems in workability and adhesion. If the temperature exceeds 330 ° C, defects such as bubble formation may occur during film production .

The first section must have the highest temperature because the polycarbonate delivered from the hopper portion must be melted smoothly, but the film can be prevented from being defective and flow in the direction of the feed block can be formed.

The second section, which is the cylinder section, is 270 to 330 ° C., and the section in which the melt extrusion from the cylinder section to the feed block is performed is divided into 3 to 9 sections, and the third to fifth sections to the third to 12 sections And the resin is melt-extruded by controlling the temperature by 5 to 10 DEG C sequentially.

When the temperature is gradually lowered by 5 to 10 ° C, the flow of the molten resin can be smoothly performed, and the bonding force between the polycarbonate and the polymethyl methacrylate resin can be increased to improve the adhesion.

When the temperature of the second section is less than 270 ° C, the interlayer adhesion of the multilayered film as a thermal adhesive resin may be weakened. If the temperature exceeds 330 ° C, the film may be broken due to pyrolysis of the sheet, Lt; / RTI >

If the temperature is controlled to be lower by 5 to 10 ° C in each section, it is difficult to obtain the effect of controlling the temperature due to a slight temperature change when the temperature is controlled to be lower than 5 ° C for each section. If the temperature exceeds 10 ° C, There may arise a problem that a foreign matter of the film is formed or a film can not be formed due to the point.

Further, the temperature of the feed block in which the multi-layer structure is formed is adjusted to 240 to 300 캜. If the temperature of the feed block is less than 240 ° C, a problem may occur that the polycarbonate is hardened in the feed block due to the high melting point of the polycarbonate. When the temperature is higher than 300 ° C, the film is hardly formed due to excessive melting.

Next, in a fifth step S50, the sheet is formed into a film shape through a tie. Specifically, the polycarbonate sheet and the polymethylmethacrylate sheet having the multilayer formed thereon are molded through a tie plate to produce a film.

Next, in the sixth step (S60), the film is calendered. Specifically, the film is calendered through the calender part to improve the roughness and gloss of both sides of the film.

Next, in the seventh step (S70), the calendered film is surface-treated. Specifically, the calendered film is modified on both sides of the film through the surface treatment section.

Next, in the eighth step S80, the surface treated film is removed. Specifically, the surface-treated film is put into an oscillation apparatus to vibrate the film to remove foreign matter.

As described above, it is to be understood that the technical structure of the present invention can be embodied in other specific forms without departing from the spirit and essential characteristics of the present invention.

Therefore, it should be understood that the above-described embodiments are to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, All changes or modifications that come within the scope of the equivalent concept are to be construed as being included within the scope of the present invention.

1. First skin layer
2. The center layer
3. Second skin layer
S10. The first step of drying the polycarbonate (PolycarPC) resin and the polymethyl methacrylate (PMMA) resin
S20. A second step of storing the polycarbonate (PC) resin in the first hopper part;
S30. And a third step of storing the polymethyl methacrylate (PMMA) resin in a second hopper part
S40. A fourth step of co-extruding the polycarbonate resin of the first hopper portion and the polymethylmethacrylate resin of the second hopper portion using a tie to produce a sheet
S41. Step 4-1 of extruding the polycarbonate resin in the first hopper portion
S42. Step 4-2 of extruding the polymethyl methacrylate (PMMA) resin in the second hopper part
S43. A multilayer sheet made of poly-methyl methacrylate (PMMA) resin as a first skin layer and a second skin layer as a core layer, extruded polycarbonate (PC) in a feed block, step
S50. A fifth step of producing the sheet in a film form through a titania
S60. A sixth step of calendering the film
S70. A seventh step of surface-treating the calendered film
S80. An eighth step of removing foreign matter from the surface-treated film

Claims (5)

A center layer made of polycarbonate (PC) resin;
A first skin layer made of polymethylmethacrylate (PMMA) resin on one side of the center layer; And
And a second skin layer made of polymethylmethacrylate (PMMA) resin on the other side of the central layer. A first step of drying a polycarbonate (PolycarPC) resin and a polymethyl methacrylate (PMMA) resin;
A second step of storing the polycarbonate (PC) resin in a first hopper part;
A third step of storing the polymethyl methacrylate (PMMA) resin in a second hopper part;
A fourth step of co-extruding the polycarbonate resin of the first hopper portion and the polymethylmethacrylate resin of the second hopper portion using a tie to produce a sheet;
A fifth step of producing the sheet in a film form through a titania;
A sixth step of calendering the film;
A seventh step of surface-treating the calendered film;
And removing the foreign matter of the surface-treated film. [7] The method according to claim 1, 3. The method of claim 2,
In the fourth step,
A fourth step of extruding the polycarbonate resin of the first hopper portion;
(4-2) extruding the polymethyl methacrylate (PMMA) resin in the second hopper portion;
A multilayer sheet made of poly-methyl methacrylate (PMMA) resin as a first skin layer and a second skin layer as a core layer, extruded polycarbonate (PC) in a feed block, A method for producing a multi-layer film, comprising the steps of: The method of claim 3,
The temperature control in the co-extrusion process is divided into 5 to 12 sections,
One section connected to the hopper section is set to 260 to 320 DEG C,
The two sections which are the cylinder sections are set to 270 to 330 캜,
3 to 5 sections to 3 to 12 sections in which the melt extrusion from the cylinder section to the feed block is performed are sequentially adjusted by lowering the temperature by 5 to 10 占 폚 based on the temperature of the cylinder section at 270 to 330 占 폚,
Wherein the temperature of the feed block is in the range of 240 to 300 占 폚. The method according to claim 1,
Wherein the thickness of the multilayer film is 15 to 100 mu m.

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