JPH10138340A - Manufacture of embossed thermoplastic resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a thermoplastic resin sheet for rapidly transferring a precise emboss shape. SOLUTION: In the method for manufacturing a multilayer thermoplastic resin sheet having a central layer 7 and surface layers 6 provided on its surfaces, it is embossed in the state that plasticizer blending amount of the layer 7 is less than that of the layer 6. It is desirable that a glass transition point of the resin of the layer 7 is higher by at least 10 deg.C than that of the layer 6. The plasticizer blending amount of the layer 7 is 0 to 40 pts. with respect to 100 pts. of the resin and the plasticizer blending amount of the layer 6 is 40 to 80 pts. with respect to 100 pts. of the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an embossed thermoplastic resin sheet. More specifically, the present invention relates to a method for producing an embossed thermoplastic resin sheet used as an interlayer film of laminated glass.

[0002]

2. Description of the Related Art Conventionally, laminated glass used for transportation equipment such as automobiles and airplanes, and windows of buildings, etc. is an interlayer film made of a thermoplastic resin such as polyvinyl butyral resin between two glass plates. Are arranged so that the fragments are not scattered around even if they are damaged.

In the production of such an interlayer film, generally, after extrusion molding, embossing is performed to prevent blocking during storage and ensure deaeration during the production of laminated glass. A method of forming irregularities is adopted.

For example, in JP-A-61-61835, as shown in FIG. 3, a thermoplastic resin S extruded in a horizontal direction from a sheet molding die 1 is cooled by a cooling press roll 3.
In addition, a method is described in which the sheet is cooled by being guided to a temperature adjusting roll 2 and then embossed by an embossing roll 4 serving as an emboss transfer plate.

[0005]

However, Japanese Patent Application Laid-Open No.
When the thermoplastic resin sheet is embossed using the technique described in Japanese Patent No. 61835, the following problem occurs.

[0006] (When the sheet temperature is high) When the sheet temperature is high, even if the sheet is pressed in the thickness direction, it spreads in the sheet width direction, so that the pressing pressure cannot be increased, and the emboss transfer rate deteriorates. Further, since the sheet hardly gets into the embossing roll (bite), a bank is generated, and it is impossible to continuously form a stable film. Further, when tension is applied for transporting the film, the film is stretched and the residual strain increases, and when heated, the film shrinks. When manufacturing laminated glass using polyvinyl butyral as a thermoplastic resin, when bonding with glass, the glass shrinks when heat is applied. Deteriorate.

(Case of low sheet temperature) When the sheet temperature is low, the resin does not flow with respect to the emboss of the plate, so that the transfer rate is deteriorated.

[0008] Since the above problems occur,
In the technique described in Japanese Patent No. 61835, it is difficult to control the sheet temperature, and high-speed and precise emboss transfer cannot be performed. If precise transfer is not possible, when laminating the polyvinyl butyral sheet and the glass, a gap is formed between the sheet and the glass, and air accumulates, which impairs the appearance of the laminated glass.

In view of the above problems, an object of the present invention is to provide a method for manufacturing a thermoplastic resin sheet that enables high-speed and precise emboss transfer.

[0010]

According to the present invention, there is provided a multi-layer thermoplastic resin sheet comprising a central layer and a surface layer provided on the surface thereof. The present invention provides a method for producing an embossed thermoplastic resin sheet, wherein embossing is performed in a state in which the amount of a plasticizer in a center layer is smaller than the amount of a plasticizer in a surface layer.

More preferably, the embossing is performed in a state where the glass transition point of the thermoplastic resin of the center layer is higher than the glass transition point of the thermoplastic resin of the surface layer by 10 ° C. or more.

For example, in the case of a polyvinyl butyral sheet, embossing is performed when the amount of the plasticizer in the center layer is in the range of 0 to 40 parts and the amount of the plasticizer in the surface layer is in the range of 40 to 80 parts. I do.

Hereinafter, the present invention will be described in detail.

In the present invention, the glass transition point is reduced and the viscosity of the surface layer is lowered by increasing the amount of the plasticizer in the surface layer. Then, since the fluidity of the resin at the same temperature is increased, the resin of the surface layer can be easily filled in the emboss of the plate. In addition, the following effects are exhibited by reducing the amount of the plasticizer in the center layer to increase the glass transition point and increase the elastic modulus. (1) Even if the sheet is pressed in the sheet thickness direction, it does not spread in the sheet width direction, so that the pressing pressure can be increased and the emboss transfer rate is improved. In addition, the problem of poor penetration (bite) of the sheet into the embossing roll does not occur, and stable continuous film formation can be performed. (2) Even if tension is applied to convey the sheet, there is little residual distortion, so that the film does not shrink even when heated.
In the case of manufacturing a laminated glass using polyvinyl butyral as a thermoplastic resin, it does not shrink even when heated when bonding with glass, so there is no dimensional problem, and the yield of the product (laminated glass) is reduced. Get better.

In order to exhibit the above-mentioned effects, it is preferable that
As described in the section, the glass transition point of the thermoplastic resin of the surface layer is 10 ° C. from the glass transition point of the thermoplastic resin of the central layer.
It is more desirable to lower the above. This is because if the temperature difference between the glass transition point of the surface layer and the center layer is not more than 10 ° C., the above effect is not sufficiently exhibited.

[0016] The range of the amount of the plasticizer in the surface layer and the center layer varies depending on the thermoplastic resin used. For example, when polyvinyl butyral is used, the amount of the plasticizer in the center layer is as follows. It is desirable to perform embossing in the range of 0 to 40 parts with respect to 100 parts of polyvinyl butyral, and in the range of 40 to 80 parts with respect to 100 parts of polyvinyl butyral with respect to 100 parts of polyvinyl butyral. If the content of the plasticizer in the center layer is more than 40 parts, the elastic modulus is low and the sheet falls down during sheet conveyance. On the other hand, if the amount of the plasticizer in the surface layer is more than 80 parts, it is difficult to peel off the plate after embossing, and the tip of the emboss on the sheet becomes thread-like. The difference in the amount of the plasticizer between the surface layer and the center layer must be at least 20 parts or more.

The plasticizer to be used is not particularly limited, however, in terms of compatibility, triethylene glycol di-2-
Ethyl butyrate, tetraethylene glycol di-2-
Ethyl butyrate, di- (butyldiglycol) adipate and the like are desirable.

Although any method can be used for forming the thermoplastic resin sheet, coextrusion is suitable. The method of embossing may be any method as long as the plate with the desired embossing can be sandwiched between sheets by an external force. For example, there is a method using a roll press, a belt press device or the like.

The plate may be in any form, for example, an embossing roll, a press plate, an embossed belt, and the like, and the plate may have any embossed shape, for example, a cone, a cylinder, a polygonal pyramid, and the like. The temperature of the plate varies depending on the type of the thermoplastic resin and the plasticizer to be used and the amount thereof, but in the case of polyvinyl butyral, the temperature is desirably 100 to 150 ° C.

[0020]

An embodiment of the present invention will be described below with reference to FIG. After forming multilayer sheets having different amounts of the plasticizer by a co-extrusion molding method, the sheet is pressed down in the thickness direction with an embossed plate. As described in claim 1, the multilayer sheet has a center layer 7 made of a thermoplastic resin containing a predetermined amount of a plasticizer, and a surface made of a thermoplastic resin containing a larger amount of a plasticizer than the center layer 7. And a layer 6.

The total number of layers of the multilayer sheet is arbitrary, but when embossing is to be applied to both sides, at least three layers are required as shown in FIG. 1, and when embossing is desired to be applied only to one side, at least two layers are required as shown in FIG. is necessary.

The pressing pressure of the sheet by the plate is determined by the sheet temperature, the emboss diameter and the emboss depth. When the sheet temperature is high, even if the pressing pressure is low, the resin easily enters the plate emboss. Also, when the pressing pressure is large, the resin easily enters the smaller diameter emboss and the deeper emboss. For example, a polyvinyl butyral sheet maintained at 100 ° C. (surface layer: plasticizer content: 60
Part, thickness: 100 μm, center layer: plasticizer content: 20
Part, thickness: 800 μm) and emboss (depth: 40 μm)
(m, diameter: 150 μm) In order to perform 100% transfer using a roll, a pressing pressure of 20 kg / cm ² or more is required. However, if the pressing pressure is applied more than necessary, the sheet will be distorted. Therefore, it is better not to apply the pressure more than necessary.

[0023]

Embodiments of the present invention will be described below.

Example 1 A resin and a plasticizer shown in Table 1 were used to prepare a surface layer (the number of plasticizer parts: 75 per 100 parts of resin).
Part, thickness: 100 μm), central layer (number of plasticizer parts: resin 1)
Emboss (diameter: 140 μm, depth: 40) a 100-degree multilayer butyral sheet maintained at 100 ° C., consisting of 25 parts with respect to 00 parts and having a thickness of 800 μm.
20 kg / c with a roll provided with a μm cone)
Embossing was performed by pressing with a pressure of m ² .

[0025]

[Table 1] (However, the glass transition point of polyvinyl butyral is 70 ° C. when triethylene glycol di-2-ethyl butyrate is 0 part.)

Thickness 1 mm (for a three-layer sheet, the total thickness is 1 mm)
mm) was pressed with an embossing press roll maintained at 120 ° C. to emboss the sheet. However, when embossing, an attempt was made to stretch the sheet so that the sheet would not sag.

The embossed sheet was evaluated according to the following evaluation items:
It was evaluated according to the eyes.Transfer rate A 10-point average surface roughness Rz was measured according to ISO3274.
The transfer rate was calculated.Heat shrinkage After immersion in warm water at 90 ° C for 1 minute, the shrinkage of the sheet was measured.
Specified. Shrinkage = ((length before shrinkage-length after shrinkage) / before shrinkage
Length) x 100 (%) Membrane sagging Evaluation was made according to the following criteria. ×: The film sags before the embossing process, and the film may be cut off in some cases.The ability of the sheet to bite into the roll when pressure is applied Evaluation was made according to the following criteria. ×: Banks are generated and stable molding is not possible. ○: Banks are not generated.

Table 2 shows the evaluation results.

Example 2 Surface layer (number of plasticizer parts: 75)
Part, thickness: 100 μm), central layer (number of plasticizer parts: 25)
Part, thickness: 800 μm), and a multilayer butyral sheet maintained at 100 ° C., which is 1.3 times stretched, is embossed (diameter: 140 μm, depth: 40 μm, conical shape) on a roll of 70 kg. After embossing by pressing at a pressure of / cm ² , the multilayer sheet was measured according to the above items. Table 2 shows the results.

[Example 3] Surface layer (number of plasticizer parts: 75)
Part, thickness: 100 μm), central layer (number of plasticizer parts: 25)
Part, thickness: 800 μm), and a multilayer butyral sheet maintained at 130 ° C., which is 1.3 times stretched, is embossed (diameter: 140 μm, depth: 40 μm, conical shape) and is provided with a roll of 50 kg. After embossing by pressing at a pressure of / cm ² , the multilayer sheet was measured according to the above items. Table 2 shows the results.

Comparative Example 1 100 ° C. with 35 parts of plasticizer
While holding the single-layer butyral sheet held at a pressure of 1.3 kg and pressing it at a pressure of 20 kg / cm ^{2 with} a roll provided with an emboss (conical shape having a diameter of 140 μm and a depth of 40 μm). Thereafter, the single-layer sheet was measured according to the above items. Table 2 shows the results.

Comparative Example 2 A single-layer butyral sheet having 35 parts of a plasticizer kept at 100 ° C. was embossed (cone having a diameter of 140 μm and a depth of 40 μm) while being stretched 1.3 times. After pressing with a roll of 70 kg / cm ^{2 at} a pressure of 70 kg / cm ² for embossing, the single layer sheet was measured according to the above items. Table 2 shows the results.

Comparative Example 3 A single-layer butyral sheet having 35 parts of a plasticizer maintained at 130 ° C. was embossed (cone having a diameter of 140 μm and a depth of 40 μm) while being stretched 1.3 times. After pressing with a roll of 20 kg / cm ^{2 at} a pressure of 20 kg / cm ² for embossing, the single-layer sheet was measured according to the above items. Table 2 shows the results.

Comparative Example 4 A single-layer butyral sheet having 35 parts of a plasticizer maintained at 130 ° C. was embossed (cone having a diameter of 140 μm and a depth of 40 μm) while being stretched 1.6 times. After pressing with a roll of 20 kg / cm ^{2 at} a pressure of 20 kg / cm ² for embossing, the single-layer sheet was measured according to the above items. Table 2 shows the results.

Comparative Example 5 Surface Layer (Plasticizer Number: 33)
Part, thickness: 400 μm), central layer (number of plasticizer parts: 43)
Part, thickness: 100 μm), a multilayer butyral sheet maintained at 100 ° C., which is stretched 1.3 times, is embossed (diameter: 140 μm, depth: 40 μm, conical type), and is provided with a roll of 50 kg. After embossing by pressing at a pressure of / cm ² , the multilayer sheet was measured according to the above items. Table 2 shows the results.

[0036]

[Table 2]

[0037]

According to the present invention, the elastic modulus of the film is increased by reducing the number of plasticizer parts in the center layer, and the following effects are exhibited. (1) Even when pressed in the thickness direction, it does not spread in the sheet width direction, so that the pressed thickness can be increased and the emboss transfer rate is good. (2) Even if tension is applied to convey the sheet, the residual distortion is small, so that the sheet does not shrink even when heated. When manufacturing a laminated glass using polyvinyl butyral as a thermoplastic resin, heat is not applied to the laminated glass when the laminated glass is bonded, so that there is no dimensional problem, and the yield of the product (laminated glass) is improved. (3) Even if the press pressure is increased in order to increase the emboss transfer accuracy, the problem that the sheet enters the embossing roll (bite in) does not occur, and a stable continuous film can be formed.

Further, according to the present invention, by increasing the amount of the plasticizer in the surface layer, the viscosity of the resin is reduced, and the following effects are exhibited. (4) Since the resin easily flows with respect to the emboss of the plate, the transfer rate is good.

As described above, by changing the amount of the plasticizer in the thickness direction, accurate emboss transfer can be performed at high speed by simple temperature control such as pressing with a plate having a temperature higher than the glass transition point of the resin in the surface layer. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing another embodiment of the present invention.

FIG. 3 is a schematic view showing a conventional embossing method.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Mold 2 Temperature control roll 3 Cooling roll 4 Emboss roll 5 Take-up roll 6 Thermoplastic resin with a large amount of plasticizer (surface layer) 7 Thermoplastic resin with a small amount of plasticizer (center layer) S Thermoplastic resin sheet

Claims (3)

[Claims] 1. A method for producing a multilayer thermoplastic resin sheet comprising a center layer and a surface layer provided on the surface thereof, wherein embossing is performed in a state where the amount of the plasticizer in the center layer is smaller than the amount of the plasticizer in the surface layer. A method for producing an embossed thermoplastic resin sheet. 2. The embossing process according to claim 1, wherein the glass transition point of the thermoplastic resin in the center layer is higher than the glass transition point of the thermoplastic resin in the surface layer by 10 ° C. or more. A method for producing a thermoplastic resin sheet. 3. The thermoplastic resin according to claim 1, wherein the amount of the plasticizer in the center layer is thermoplastic resin 1.
3. The embossing process according to claim 1, wherein the embossing is performed in the range of 0 to 40 parts per 100 parts, and the plasticizer content of the surface layer is in the range of 40 to 80 parts per 100 parts of the thermoplastic resin. A method for producing an embossed thermoplastic resin sheet.