JP2001163641A - Thermoplastic resin intermediate film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin intermediate film which is excellent in handling workability during storage or in processing laminated glass, is excellent in deaerability and sealability in a preliminary compression bonding stage and consequently hardly gives rise to the quality defect by the generation of air bubbles, is suitable for obtaining a high-quality laminated glass and is easily and efficiently dealable with diversified processing conditions of diversified users. SOLUTION: Many embosses 3 consisting of fine ruggedness are formed on both surfaces of the thermoplastic resin sheet molded by extrusion molding and hollow grooves 2 are formed on at least one surface. The angle between these hollow grooves and the extrusion direction of the thermoplastic resin sheet is <25 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a thermoplastic resin interlayer. In addition, in this specification, a "sheet"
It does not mean a sheet in a strict sense based on thickness, but also includes a relatively thin sheet called “film”.

[0002]

2. Description of the Related Art An intermediate film of a thermoplastic resin such as plasticized polyvinyl butyral (hereinafter simply referred to as "intermediate film") is provided between glass plates.
) Is interposed, bonded and integrated, and is widely used for window glasses of automobiles, aircraft, buildings and the like.

[0003] This type of laminated glass is usually a so-called handle deaeration method in which an interlayer is sandwiched between at least two glass plates and handled by passing it through a nip roll, or a glass bag is suctioned under reduced pressure to suck the glass. It is manufactured by pre-press bonding by a so-called reduced pressure degassing method of degassing the air remaining between the plate and the intermediate film, and then performing heating and pressurization in an autoclave to perform main pressing.

[0004] In the above-mentioned handling deaeration method and decompression deaeration method, in producing an interlayer film, good deaeration is required in order to eliminate generation of air bubbles due to entrainment of air during pre-compression bonding. You.

In order to satisfy such requirements, a large number of embosses having fine irregularities are usually formed on both surfaces of the intermediate film. Examples of the form of the unevenness include, for example, various convexo-concave patterns composed of a large number of convex portions and a large number of concave portions for these convex portions, and various concave-convex patterns composed of a large number of convex portions and a large number of concave grooves for these convex portions. Uneven patterns and the like are known.
However, since the above-mentioned uneven pattern is usually provided at random by subjecting the roll to sand blasting, it has been difficult to perform sufficient degassing.

Therefore, Japanese Patent Publication No. 1-37762 discloses a method in which fine irregularities (embosses) are formed on a surface of a film or sheet by a large number of independent protrusions.
There has been proposed an interlayer film formed so as to have continuous concave portions at the same level.

However, although the above-mentioned interlayer film has considerably improved the anti-blocking property during storage and the handling workability, or the degassing property in the pre-compression bonding step, for example, a laminated glass having a large area and a curvature In the case of manufacturing a laminated glass having a large diameter, or when it is desired to increase the productivity at the time of processing the laminated glass, there is a problem that the degassing property in the pre-compression bonding step is not yet sufficiently satisfactory.

[0008] Further, in the case of performing pre-compression bonding by the handling deaeration method and the case of performing pre-compression bonding by the reduced pressure deaeration method,
The former was degassed under pressure and the latter was degassed under reduced pressure, and there was a large difference in the pre-press bonding conditions. In some cases, pre-press bonding was not possible where only one facility was provided.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems by providing excellent workability during storage and processing of laminated glass, as well as excellent deaeration and sealing properties in a pre-compression bonding step. Therefore, it is suitable for obtaining a high-quality laminated glass which hardly causes poor quality due to the generation of bubbles, and is also suitably used as an interlayer for laminated glass which can easily and efficiently cope with various processing conditions of various users. It is an object of the present invention to provide a thermoplastic resin interlayer.

[0010]

The intermediate film of the present invention has a thermoplastic resin sheet formed by extrusion, in which a large number of embosses having fine irregularities are formed on both surfaces, and a concave groove is formed on at least one surface. The angle between the groove and the extrusion direction of the thermoplastic resin sheet is less than 25 °.

The resin used for the thermoplastic resin sheet used in the present invention is not particularly limited. For example, plasticized polyvinyl acetal resin, urethane resin, ethylene-vinyl acetate copolymer resin, ethylene resin -A thermoplastic resin sheet conventionally used for an intermediate film, such as an ethyl acrylate copolymer-based resin or a plasticized vinyl chloride-based resin, may be used, and is preferably used. These thermoplastic resins are excellent in basic performance required as an interlayer such as adhesiveness, weather resistance, penetration resistance and transparency.

Among the above thermoplastic resins, a plasticized polyvinyl acetal resin represented by a plasticized polyvinyl butyral resin is particularly preferably used. The thickness of these thermoplastic resin sheets is not particularly limited, and may be set in consideration of the penetration resistance and the like required as a laminated glass,
As in the case of the conventional interlayer, the thickness is preferably 0.2 to 2 mm.

The shape of the embossments formed on both sides of the thermoplastic resin sheet is not particularly limited, and any conventionally known shape can be selected.

If the angle formed between the groove formed in the thermoplastic resin sheet used in the present invention and the extrusion direction of the thermoplastic resin sheet is too large, the intermediate film of the present invention will not be formed.
In particular, when manufacturing laminated glass by pre-compression by the handling method, foaming (bubbles) is likely to occur in the laminated glass, and if the above-mentioned concave groove is on the edge of the sheet, it will be heated and pressed in the autoclave. When performing the final press bonding, poor sealing may occur and air may be entrained.
Less than 15 °, preferably less than 15 °.

The depth of the groove is preferably 5 to 500 μm, more preferably 20 to 70 μm. In this case, the concave groove is a continuous groove,
It is preferable that the depth, width and pitch are constant. However, the groove bottom may have an appropriate undulation, or may be provided irregularly with different depth, width and pitch.

Further, if the width of the groove is too narrow, the degassing property is reduced, and if it is too wide, poor sealing is likely to occur.

Further, the pitch of the above-mentioned concave grooves decreases the degassing property, and if the pitch is too wide, poor sealing is likely to occur.
It is preferably 0.1 to 10 mm, and more preferably 0.1 to 10 mm.
2-1 mm.

In the present invention, the concave groove may be provided on at least one surface of the thermoplastic resin sheet, may be provided on only one surface, or may be provided on both surfaces. Is preferably provided on both sides in order to ensure

The sectional shape of the concave groove is not particularly limited, and examples thereof include a V-shape, a U-shape, and a U-shape.

In the present invention, a large number of embosses having fine irregularities are formed on both surfaces of the thermoplastic resin sheet in addition to the concave grooves. The distribution of the unevenness may be provided regularly or irregularly.

The dimensions of the embossed concavo-convex pattern are not particularly limited, but when convex portions are regularly provided, the interval between adjacent convex portions is preferably in the range of 10 to 2000 μm. , More preferably 50-100
The range is 0 μm. In addition, the height of the projection is 5 to 500 μm.
m, more preferably 20 to
The range is 100 μm. Further, it is preferable that the length of the base of the convex portion is approximately in the range of 30 to 1000 μm.

The depth of the concave portion and the height of the convex portion are
All may be the same or different.

The embossed shape is not particularly limited, but is generally a pyramid such as a triangular pyramid, a quadrangular pyramid, a cone, or the like; a truncated triangular pyramid, a truncated square pyramid, a truncated cone, or the like. Head cone;
It is preferable that the projections and depressions have a number of projections made of a pseudo cone having a mountain-shaped or hemispherical head and a number of depressions corresponding to these projections.

As a method of forming a large number of embosses formed of concave grooves and fine irregularities on both surfaces of a thermoplastic resin sheet,
It is not particularly limited, for example, an embossing roll method, a calender roll method, a profile extrusion method, an extrusion lip embossing method using a melt fracture, and the like. An embossing roll method capable of forming an emboss is suitably employed.

The embossing roll used in the embossing roll method is not particularly limited. For example, the surface of a metal roll is subjected to a blast treatment using an abrasive such as aluminum oxide or silicon oxide, and then the surface is excessively enlarged. Lapping by vertical grinding etc. to reduce the peak, forming a fine uneven pattern on the roll surface, using an engraving mill (mother mill), transferring the uneven pattern to the metal roll surface, Those having a fine concavo-convex pattern, those having a fine concavo-convex pattern formed on the roll surface by etching (etching), and the like are mentioned, and are preferably used.

When a laminated glass is produced using the interlayer film of the present invention, specifically, for example, preliminary compression bonding and main compression bonding are performed as follows.

First, the pre-compression bonding includes, for example, a method in which an intermediate film is sandwiched between two transparent inorganic glass plates, the laminate is passed through a nip roll (pressing roll), and pre-compression bonding is performed while degassing. As the method of pre-press bonding while degassing, for example, 1) pressure of about 200 to 1000 kPa, temperature of about 50 to 80
2) Putting the above-mentioned laminate in a rubber bag, for example, and connecting the rubber bag to an exhaust system to about -1.3-53 kPa. A method in which the temperature is increased while reducing the pressure by suction, and pre-compression bonding is performed at a temperature of 50 to 100 ° C. (vacuum degassing method).

Next, the pre-pressed laminate is subjected to a conventional method using an autoclave or a press, for example, at a temperature of 120 to 150 ° C. and a pressure of 1000 to 1500 kPa, to produce a laminated glass.

The glass plate is not limited to an inorganic glass plate, but may be an organic glass plate such as a polycarbonate plate or a polymethyl methacrylate plate, or a combination of an inorganic glass plate and an organic glass plate. Is also good. The laminated structure of the laminated glass is not limited to the usual three-layer structure of a glass plate / intermediate film / glass plate.
It may have a multilayer structure such as an interlayer / glass plate / interlayer / glass plate.

(Function) In the intermediate film of the present invention, a large number of embosses having fine irregularities are formed on both surfaces of a thermoplastic resin sheet formed by extrusion molding, and a concave groove is formed on at least one surface. And the angle between the extrusion direction of the thermoplastic resin sheet and the direction of extrusion of the thermoplastic resin sheet is less than 25 °, and therefore, at least one side has a concave groove shape. Even if the embossment is crushed by pressing, the continuous groove shape of the concave portion remains until the final stage. Therefore, sufficient degassing can be performed.

In the case where the pre-compression bonding step is performed by the handling method, the ease of air release in the pre-compression bonding step is closely related only to the ratio of the groove to the entire recess and the smoothness of the groove. It has little effect on the spacing and arrangement. Also, for example, if a mountain-shaped convex shape is provided, and a degassing passage is provided in a lattice shape, there is no problem when degassing in a direction along the mountain range, but when degassing at a right angle to the mountain range, Air accumulation occurs, resulting in poor deaeration. However, the intermediate film of the present invention can secure an air passage by providing a concave groove parallel to the extrusion direction, and therefore does not block the air even if it is degassed in a direction perpendicular to the concave groove. No problem occurs.

Further, according to a recent laminated glass manufacturing method, the laminated glass is formed along the winding direction of the interlayer film (ie, generally, the extrusion direction of the thermoplastic resin), and the laminated glass is formed in the winding direction. In many cases, a groove is formed along the winding direction of the intermediate film, so that the sealing property of the peripheral portion of the intermediate film is excellent in the pre-compression bonding step, since the air is often degassed by being handled along the intermediate film. . Also, when pre-compressing laminated glass components, many processing manufacturers set the initial speed of inserting the component into the multi-roll and the speed before release in order to prevent cracking due to bending of the glass. Because it passes through clearly slower than the speed, the sealing state before and after the structure can be sufficiently sealed even if the roughness of the emboss and the groove shape hitting before and after the structure are large,
Since there is no groove at the side end of the structure, there is no problem in the sealing property of the side end.

In the case of the vacuum degassing method, the unevenness of the surface of the intermediate film does not greatly affect the ease of air release during the vacuum degassing in the pre-compression bonding step. It is effective enough to make it easier. Regarding the sealing property, since the periphery is uniformly sealed with a rubber bag, the arrangement direction of the concave grooves does not matter.

[0034]

EXAMPLES The present invention will be described in more detail with reference to Examples.

FIG. 1 shows an example of a thermoplastic resin interlayer according to the present invention, wherein (a) is a plan view and (b) is a side view.

As shown in FIG. 1, the intermediate film 1 of the present invention
A plurality of embosses 3 (not shown) made of fine irregularities are formed on both surfaces of a thermoplastic resin sheet formed by extrusion molding, and a concave groove 2 is formed on one surface, and the concave groove 2 and the thermoplastic resin sheet are formed. Are provided substantially in parallel with the extrusion direction X.

Production of Intermediate Film (Example 1) A thermoplastic resin sheet obtained by extruding a plasticized polyvinyl butyral resin into a sheet (trade name “ESLEK film DXN film” manufactured by Sekisui Chemical Co., Ltd.)
The thickness of the triangular prism corresponding to the shape of the groove 2 shown in FIG. 1 (height: 760 μm) (height: 120 μm, base: 150 μm,
(A distance of 300 μm) is continuously formed in the axial direction, and a metal roll having a randomly formed uneven pattern on the surface other than the protrusions, and 45 to 7 having a randomly formed uneven pattern on the surface.
A pair of rolls composed of a rubber roll having a JIS hardness of 5 is used as an uneven transfer device, and the thermoplastic resin sheet is passed through the uneven transfer device, and a groove 2 is formed on one surface of the sheet in parallel with the extrusion direction. An intermediate film formed continuously and having embossed portions formed on both surfaces was obtained. The transfer conditions at this time were as follows. DX film temperature: normal temperature, roll temperature: 120 ° C, linear velocity: 1
0 m / min, press linear pressure: 500 kPa

(Comparative Example 1) An intermediate film was obtained in the same manner as in Example 1, except that the protrusions of the triangular prism of the metal roll were provided at an angle of 45 ° with the axial direction.

Comparative Example 2 An intermediate film was obtained in the same manner as in Example 1, except that the protrusions of the triangular prism of the metal roll were provided in the circumferential direction.

Comparative Example 3 A V-shaped concave groove was provided in the circumferential direction instead of the triangular prism projection of the metal roll.
An intermediate film was obtained in the same manner as in Example 1.

The intermediate films obtained in Example 1 and Comparative Examples 1 to 3 were subjected to the following evaluations.

Ten point average surface roughness {Rz (μm)} Digital type stylus Electric cone-shaped stylus (product name: SE-2000, manufactured by Kosaka Laboratory Co., Ltd.) JIS, using a tip curvature radius of 5 μm and a vertex angle of 90 degrees)
The ten-point average surface roughness ΔRz (μm) of the intermediate film was measured in accordance with B-0601.

Baking test After pre-compression bonding was performed by the following two methods ((a) handling deaeration method and (b) reduced pressure deaeration method), final compression bonding was performed to produce a laminated glass.

(A) Handling and deaeration method The interlayer film is made of two transparent float glass plates (length 30 cm ×
30cm wide x 2mm thick, 1mm around the central part
(A curved glass), cut off the protruding portion, and place the thus obtained laminate in a heating oven at a temperature (pre-compression bonding temperature) of the laminate of 70 ° C. and 80 ° C., respectively.
After heating to 90 ° C., the nip roll (air cylinder pressure 35.5 MPa, linear velocity 10 m /
Min) to perform pre-compression bonding.

(B) Vacuum degassing method The interlayer film is formed of two transparent float glass plates (length 30 cm ×
30cm wide x 2mm thick, 1mm around the central part
Between the curved glass), cut off the protruding part, transfer the laminate thus obtained into a rubber bag,
The rubber bag is connected to a suction decompression system, heated at the outside air heating temperature and simultaneously with -600 mmHg (absolute pressure 160 mmH
After holding the laminate under the reduced pressure of g) for 10 minutes and heating the laminate to a temperature (preliminary compression temperature) of 70 ° C., 80 ° C., and 90 ° C., respectively, the pressure was returned to the atmospheric pressure to complete the preliminary pressure bonding.

Each of the laminates preliminarily pressed by the methods (a) and (b) was heated at a temperature of 14 ° C. in an autoclave.
After holding at 0 ° C. and a pressure of 1.3 MPa for 10 minutes, the temperature was lowered to 50 ° C. and returned to the atmospheric pressure to complete the final pressure bonding, thereby producing a laminated glass.

The laminated glass obtained above was heated in an oven at 140 ° C. for 2 hours. Next, after taking out from the oven and allowing to cool for 3 hours, the appearance of the laminated glass was visually observed, the number of foams (bubbles) generated in the laminated glass was examined, and the degassing property and sealing property were evaluated. The number of test sheets was 100. The smaller the number of foamed laminated glasses, the better the degassing and sealing properties.

[0048]

[Table 1]

[0049]

Since the interlayer film of the present invention is constructed as described above, it has excellent handling workability during storage and processing of laminated glass, and also has excellent deaeration and sealing properties in the pre-compression bonding step. The interlayer film is suitable for obtaining a high-quality laminated glass that hardly causes poor quality due to the generation of bubbles, and can easily and efficiently cope with various processing conditions of various users.

[0050]

[Brief description of the drawings]

FIG. 1 shows an example of a thermoplastic resin interlayer according to the present invention, wherein (a) is a plan view and (b) is a side view.

[Explanation of symbols]

 1 groove shape of concave part of interlayer film 2 concave groove 3 emboss

Claims (1)

[Claims] 1. A thermoplastic resin sheet formed by extrusion molding has a large number of embosses having fine irregularities formed on both sides thereof, a concave groove formed on at least one side, and a direction in which the concave groove and the thermoplastic resin sheet are extruded. Is less than 25 °.