JPH10138339A - Manufacture of embossed thermoplastic resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a sheet having small thermal shrinkage factor of an embossed product by continuously molding the stable sheet without film sagging without generation of a bank (reservoir of resin) by accurately transferring an emboss shape and satisfactorily biting the sheet into an embossing roll. SOLUTION: The method for manufacturing an embossed thermoplastic resin sheet comprises the steps of laminating a thermoplastic resin (e.g. plasticized polyvinyl-butyral resin) sheets A (sheets 11, 13) and a thermoplastic resin (e.g. plasticized polyvinyl butyral resin) sheet B (sheet 12) having lower by 10 to 50 deg.C than that of the sheet A to transfer an emboss shape to the sheets A, applying a pressure thereto and transferring the shape to the sheet A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an embossed thermoplastic resin sheet, and more particularly to a thermoplastic resin having an embossed shape on both surfaces or one surface, suitable for an interlayer film for laminated glass and the like. The present invention relates to a sheet manufacturing method.

[0002]

2. Description of the Related Art A laminated glass in which an adhesive intermediate film made of a plasticized polyvinyl butyral resin or the like is sandwiched between two transparent glass plates has a large strength, is hard to be broken, and even if broken, fragments are not scattered. Glass material,
2. Description of the Related Art Conventionally, it has been widely used for transportation equipment such as automobiles and airplanes or window glass of buildings and the like.

[0003] The interlayer film used for such a laminated glass is free from a so-called blocking phenomenon in which the interlayer films adhere to each other to form a block during storage, and has good workability when laminating the glass and the interlayer film. , And good deaeration in the pre-compression bonding step. As an intermediate film satisfying this requirement, a resin film generally called an embossed sheet is used. The embossed sheet is formed by providing a large number of fine irregularities called embossed on both surfaces or one surface of a resin film.

A method of manufacturing an embossed sheet is disclosed in, for example, Japanese Patent Application Laid-Open No. 61-61835 (hereinafter referred to as Prior Art 1). In this method, as shown in FIG. 2, a thermoplastic resin sheet 26 extruded in a horizontal direction from a molding die 21 is cooled by cooling rolls 22, 22.
In this method, the sheet 26 is guided to the temperature adjusting rolls 23a, 23b, 23c, and 23d to adjust the surface of the sheet 26 to a predetermined temperature, and the embossing rolls 24 and 24 perform embossing. In addition, 25 is a take-up roll.

In Japanese Unexamined Patent Publication No. 3-284935 (hereinafter referred to as "prior art 2"), as shown in FIG. 3, a thermoplastic resin sheet 3 extruded from a mold 31 into a sheet is used.
After being drawn into the water tank 33 by the guide rolls 32a and 32b and cooled, the sheet 8 is guided to the temperature adjusting rolls 35a, 35b, 35c and 35d through the draining rolls 34 and 34 to heat the sheet surface.
In steps 6 and 36, the embossed shape is transferred to the surface of the sheet 38. In addition, 37 is a take-up roll.

[0006]

However, in the prior art 1, the following problems are likely to occur depending on the temperature of the thermoplastic resin sheet 26.

That is, when the temperature of the sheet is high,
Since the sheet is soft, if pressure is applied with an embossing roll, the sheet will spread in the width direction, so that sufficient pressure cannot be applied, and therefore the emboss transfer rate to the sheet will not increase. Further, the sheet is hard to bite into the embossing roll, and a bank (pool of resin) is generated just before the roll, which makes it difficult to continuously form a stable sheet continuously.
Further, if the tension for conveying the sheet is small, the film drips, and in some cases, the film breaks, making continuous molding difficult. If the tension is increased to prevent this, the sheet is stretched and residual strain tends to remain on the sheet. If residual strain remains in the sheet, the sheet shrinks when heated in the laminated glass manufacturing process, causing a problem that defective products are generated in the laminated glass.

[0008] When the temperature of the sheet is low, emboss transfer to the sheet tends to be insufficient even when pressure is applied due to insufficient softness of the sheet.

Conventional technique 2 has been proposed to solve the above problem. This technique is intended to provide a temperature difference between the sheet surface and the central portion to improve the emboss transfer rate on the surface, and to prevent generation of banks and residual distortion. However, in this method, the temperature difference between the central portion and the surface can be provided only about 3 to 7 ° C., and when the surface temperature is increased to increase the emboss transfer rate, the central portion is softened, and the generation of banks and the generation of residual distortion occur. Cannot be sufficiently prevented.

[0010] The present invention has been made in view of the above problems, and can accurately transfer an embossed shape.
The sheet can be cut into the embossing rolls well, no banks (pools of resin) are generated, and stable continuous sheet formation without film dripping is possible. Furthermore, the heat shrinkage of the embossed product can be reduced. An object of the present invention is to provide a method for producing an embossed thermoplastic resin sheet which can be reduced in size.

[0011]

According to the present invention, in transferring an embossed shape to a thermoplastic resin sheet A, the sheet A and a thermoplastic resin sheet B having a temperature lower by 10 to 50 ° C. than the sheet A are used. This is a method for producing an embossed thermoplastic resin sheet, which comprises laminating, applying pressure, and transferring the embossed shape to sheet A.

If the temperature difference between the sheet A and the sheet B is less than 10 ° C., the emboss transfer rate cannot be increased.
When the temperature exceeds 0 ° C., the sheet A is cooled by heat conduction in the thickness direction and the emboss transfer ratio cannot be increased, so that the temperature difference between the sheet A and the sheet B is limited to 10 to 50 ° C.

The resin used in the present invention is not particularly limited as long as it is a thermoplastic resin.
An acrylic resin, a polyester resin, an olefin resin, a butyral resin, a polycarbonate resin, a polyimide resin, or the like can be used.

A plasticizer is added to the thermoplastic resin as required. In particular, when using a butyral-based resin, it is preferable to add a plasticizer. Examples thereof include triethylene glycol-2-ethyl butyrate, tetraethylene glycol di-2-ethyl butyrate, and di-butyl diglycol adipate. .

The thermoplastic resin sheet A and the thermoplastic resin sheet B may be the same resin, or may be different resins if lamination is possible.

For cooling or heating for providing a temperature difference between the sheet A and the sheet B, a conventionally known device or method can be used. For example, examples of the cooling method include a water bath, a roll, a belt, and air. Also, as the heating method,
Rolls, belts, hot air, far-infrared rays and the like can be mentioned.

As the sheet A, a sheet in a molten state immediately after being extruded from a mold may be used. The sheet B may be used by cooling a sheet in a molten state immediately after being extruded from a mold so that the temperature is lower by 10 to 50 ° C. than that of the sheet A. The temperature may be adjusted and used.

When the target product is a front and back double-sided embossed product, the sheet B is a core layer, and the sheet A is a laminated sheet of at least three layers with the front and back sides. And a sheet B of at least two layers.

The above-mentioned lamination method may be any method as long as the sheet A and the sheet B are laminated without displacement. For example, when a plasticized polyvinyl butyral resin is used as the thermoplastic resin, it is preferable to extrude the sheet A and the sheet B, and then adjust the temperature of each of the sheets and stack the sheets.

The embossed shape transfer method used in the present invention may be any method as long as the embossed shape can be transferred to the sheet A by pressing, for example, an embossed roll method or a metal belt method.

The embossing roll may be any embossed shape provided on a metal roll, and any embossing method may be used, including all general methods such as engraving, corrosion, and sandblasting. As the shape of the emboss, a cone, a cylinder, a polygonal pyramid, or the like is appropriately adopted as desired for a product. Further, the roll surface may be subjected to various treatments such as plating treatment, ceramic treatment, silicon coating, and Teflon coating. Further, it is preferable that the temperature can be controlled, and the control method is not particularly limited.

The above-mentioned metal belt may be a loop-shaped one. For example, both ends of the metal belt may be connected by welding or the like. The surface may be provided with an embossed shape similar to the embossing roll. Further, the surface may be subjected to various treatments such as plating, ceramic, silicon coat, and Teflon coat.

The lamination of the sheet A and the sheet B and the transfer of the embossed shape to the sheet A may be performed simultaneously, or may be performed in two steps as a separate step. When the embossed shape is transferred to the front and back sides, the transfer may be performed simultaneously for the front and back sides, or may be performed separately for the front and back sides. However, in consideration of maintaining the temperature difference between the sheet A and the sheet B, it is preferable that the above-described lamination and the transfer of the emboss are performed simultaneously, and it is preferable that the transfer of the embossed shape to the front and back is also performed simultaneously.

[0024]

According to the present invention, since the temperature of the thermoplastic resin sheet A can be increased, accurate transfer can be performed even if the embossed shape is fine or deep.

Further, since the thermoplastic resin sheet B is at a low temperature, the sheet is not stretched by the tension at the time of conveying the sheet, and therefore, a product having a small residual strain and a small heat shrinkage can be obtained. For example, when the obtained embossed sheet is used as an interlayer film for laminated glass, a defective rate in a laminated glass manufacturing process can be reduced. Further, the sheet is well bitten into the embossing roll, and there is no generation of a bank (pool of resin), and stable continuous forming of the sheet is possible.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIG.

By the extrusion molding method, the molten thermoplastic resin sheets 11, 1 and 1 are separated from the mold 1, the mold 2, and the mold 3, respectively.
Extrude 2,13. In this case, the sheets 11 and 13 correspond to the thermoplastic resin sheet A, and the sheet 12 corresponds to the thermoplastic resin sheet B. Immediately after leaving the mold, the sheet 12 is guided to the water tank 5 by the guide rolls 4a and 4b and cooled in water. The sheet 11 and the sheet 13 are respectively
a, 6b, 6c and the temperature control rolls 7a, 7b,
The sheet 12 is adjusted to a predetermined temperature through draining rolls 8 and 8 and guided to a pair of embossing rolls 9 and 9, where the lamination of each sheet and the sheets 11 and 1 are performed.
The transfer of the embossed shape to No. 3 is performed. In addition, 10 is a take-up roll.

In the present invention, the temperature of the sheet A when it reaches the embossing rolls 9, 9 is lower by 10 to 50 ° C. than the temperature of the sheet B. When a plasticized polyvinyl butyral resin is used for both the sheet A and the sheet B as the thermoplastic resin, the temperature of the sheet A is set to 90 to 250.
° C and the temperature of sheet B is 10 to 10 degrees higher than the temperature of sheet A.
Preferably, the temperature is lowered by 50 ° C.

The surface temperature of the embossing rolls 9, 9 of the present invention varies depending on the type of thermoplastic resin, the temperature of the sheet A, the shape of the embossing, and the like. For example, in the case of a plasticized polyvinyl butyral resin sheet at 130 ° C., 120-16
0 ° C. is preferred.

The pressure of the embossing rolls 9, 9 also varies depending on the type of the thermoplastic resin, the sheet temperature, the temperature of the embossing roll, the emboss shape, and the like. For example, as the thermoplastic resin, both sheet A and sheet B are plasticized polyvinyl butyral resins, and the temperature of sheet A is 130
° C, temperature of sheet B is 60 ° C, embossed shape has depth of 80
The pressing pressure of the embossing roll in the case of a conical shape having a diameter of 70 μm is preferably about 20 kg / cm.

[0031]

【Example】

(Examples 1 to 3, Comparative Examples 1 to 4) Hereinafter, examples of the present invention will be described. 1. Sheets A and B of thermoplastic resin raw materials Examples 1 to 3, and Comparative Examples 1 to 4
Both sheets used a plasticized polyvinyl butyral resin obtained by adding and kneading 40 parts by weight of triethylene glycol di-2-ethyl butyrate as a plasticizer to 100 parts by weight of polyvinyl butyral having a degree of butyralization of 65 mol% and a degree of polymerization of 1700. .

[0032] 2. Forming into Sheets and Conveying Sheets In Examples 1 to 3, three sheets were formed using the apparatus shown in FIG. The thickness of each of the front and back sheets A was 100 μm, and the thickness of the center sheet B was 800 μm. Since the temperature of the sheet A is high, the sheet extends while the sheet is being conveyed. This elongation is shown in Table 1 as a stretching ratio. In Comparative Examples 1 to 4, a sheet having a thickness of 1000 μm was formed using the apparatus shown in FIG. Table 2 shows the stretching ratio during sheet conveyance.

[0033] 3. Laminated and embossed transfer Examples 1-3 and Comparative Examples 1-4 all have a depth of 80μ
Lamination and embossing were simultaneously performed using a pair of embossing rolls having a conical embossing shape of m and a diameter of 70 μm. The temperature of the embossing roll at this time was 130 ° C. Tables 1 and 2 show the sheet temperature and the pressing pressure of the embossing roll in each of the examples and the comparative examples.

[0034] 4. Evaluation (1) Film sagging property The state of the sheet before entering the embossing roll was visually observed,
Tables 1 and 2 show that the sheet sags before the roll and that the sheet breaks depending on the case, and that the sheet does not sag is o. (2) Biting property into embossing roll Visually observe the biting property of the sheet into the embossing roll,
Tables 1 and 2 show "x" when the bank was generated and the molding was not stable, and "o" when the bank was not generated and the bite was good. (3) Emboss transfer rate The obtained embossed sheet was measured for 10-point average surface roughness Rz according to ISO3274, and the transfer rate was calculated. The results are shown in Tables 1 and 2. (4) Heat Shrinkage After the obtained embossed sheet was immersed in warm water at 90 ° C. for 1 minute, the dimensional change of the sheet was measured to determine the heat shrinkage, and the results are shown in Tables 1 and 2.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

The construction of the method for producing an embossed thermoplastic resin sheet of the present invention is as described above. According to the production method of the present invention, the embossed shape can be accurately transferred. In addition, the sheet can be bitten into the embossing rolls with good quality, no banks (pools of resin) are generated, and stable continuous formation of the sheet without sagging of the film is possible. Further, the heat shrinkage of the embossed product can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an example of an apparatus used for carrying out the present invention.

FIG. 2 is a configuration diagram of an apparatus used in the related art 1.

FIG. 3 is a configuration diagram of an apparatus used in the related art 2.

[Explanation of symbols]

 1, 2, 3 Mold 4a, 4b Guide roll 5 Water tank 6a, 6b, 6c, 7a, 7b Temperature control roll 8, 8 Draining roll 9, 9 Embossing roll 10 Take-up roll 11, 12, 13 Thermoplastic resin sheet

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29L 9:00

Claims (1)

[Claims] 1. In transferring an embossed shape to a thermoplastic resin sheet A, the sheet A and a thermoplastic resin sheet B having a temperature lower by 10 to 50 ° C. than the sheet A are laminated and pressure is applied. A method for producing an embossed thermoplastic resin sheet, wherein the embossed shape is transferred to A.