JP2000203900A - Interlayer for laminated glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interlayer for a laminated glass having excellent blocking resistance during storage and handling workability in the insertion of the interlayer between glass plates, exhibiting deaeration workability in a preparatory pressing stage and enabling the preparatory pressing in high efficiency. SOLUTION: The interlayer for a laminated glass is composed of a thermoplastic resin sheet embossed at both surfaces to form small protrusions and recesses. The surface roughness of at least one of the embossed surfaces satisfies the formulas Ra=3.5 to 7.0 μm and Rab/Ra=15 to 25%. In the above formulas, Ra and Rab are each an arithmetic average roughness (μm) determined in conformity to JIS B 0601 using the cut-off value of 2.5 mm for Ra and 0.08 mm for Rab.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interlayer film for laminated glass on which an emboss having fine irregularities is formed.

[0002]

2. Description of the Related Art Laminated glass obtained by sandwiching an interlayer made of a thermoplastic resin sheet such as plasticized polyvinyl butyral between glass plates and bonding them together is widely used for window glasses of automobiles, aircraft, buildings and the like. I have.

[0003] In this type of laminated glass, usually, an interlayer film is sandwiched between glass plates and handled by passing through a nip roll (handling roll method) or put in a rubber bag and suctioned under reduced pressure (vacuum bag method). It is manufactured by performing pre-compression bonding while removing air remaining between the plate and the interlayer, and then performing heating and pressing in an autoclave to perform main compression.

The interlayer of the laminated glass has adhesiveness,
In addition to good basic performance such as weather resistance, penetration resistance, transparency, etc., interlayer films do not block during storage, and handling workability when sandwiching interlayer films between glass plates is good. Further, in order to eliminate air entrapment, it is required that the deaeration in the pre-compression bonding step be good.

[0005] In particular, the deaeration in the pre-compression bonding step affects the quality of the laminated glass. If the degassing is insufficient, the resulting laminated glass may have poor transparency or foam (bubbles) when used under severe conditions.

In order to satisfy such demands, a large number of fine irregularities (embosses) are usually formed on the surface of the interlayer film for laminated glass. As a form of a large number of fine irregularities, various irregularities composed of a large number of convex portions and a large number of concave portions corresponding to these convex portions have been proposed (for example, Japanese Patent Application Laid-Open No. 60-206443 and Japanese Patent Publication No. 1-3
No. 2776).

[0007]

However, in the above-mentioned conventional interlayer film for laminated glass, the deaeration property in the pre-compression bonding step is not yet sufficient, and especially the laminated glass having a large area and the laminated glass having a large curvature are not enough. When manufacturing glass, when increasing the productivity of laminated glass, or when using laminated glass under severe conditions such as using at a high temperature, foaming may occur.

For example, in order to increase the productivity of laminated glass, if pre-compression is performed by the handling roll method, the speed of the handling roll increases, so that the emboss cannot be sufficiently collapsed.
Foaming due to poor sealing is likely to occur. In addition, when pre-compression bonding is performed by the vacuum bag method, the laminated body may be put in the rubber bag in a state where the temperature of the rubber bag does not sufficiently lower, and the emboss is quickly crushed at the start of deaeration, resulting in poor deaeration and foaming Sometimes.

In particular, Japanese Patent Publication No. 1-32776 discloses that
An intermediate film having a large number of independent protrusions such as a quadrangular pyramid, and having an embossment of a concavo-convex pattern in which all the recesses to the protrusions are continuous at the same level, has been proposed. Has a configuration in which air is easy to escape during degassing, but it is actually difficult to uniformly and regularly form the shape of the unevenness and the depth and height of the unevenness,
It is more or less non-uniform and the degassing is not fully satisfactory. Further, in the interlayer film proposed above, the embossments are formed relatively uniformly and regularly, so that the interlayer films are likely to be blocked.

The present invention solves the above problems,
Its purpose is to provide an interlayer film for laminated glass that is excellent in blocking resistance between films during storage and handling workability when sandwiching an interlayer film between glass plates, and is excellent in deaeration in the pre-compression bonding step. To provide.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide an interlayer film for laminated glass in which embosses composed of fine irregularities are formed on both surfaces of a thermoplastic resin sheet. This can be achieved by an interlayer film for laminated glass, which is characterized in that it has a Rab / Ra ratio of 15 to 25% in a range of 3.5 to 7.0 μm.

Here, Ra and Rab are JIS B 06
01 represents the arithmetic average roughness (μm), Ra is a value when the cutoff value is 2.5 mm, and Rab
Is a value when the cutoff value is 0.08 mm.
Note that such arithmetic average roughness Ra is DIN 476
2 and 4768, and ISO 468 and 4287.

As the thermoplastic resin sheet used in the present invention, a sheet used for a conventional interlayer film of laminated glass is used. For example, a plasticized polyvinyl acetal resin sheet, a soft polyurethane resin sheet, an ethylene-vinyl acetate resin sheet, an ethylene-ethyl acrylate resin sheet, a plasticized vinyl chloride resin sheet, and the like can be given. These sheets have excellent basic performance required for laminated glass, such as adhesion, weather resistance, penetration resistance, and transparency.

Particularly, a plasticized polyvinyl acetal resin sheet represented by a plasticized polyvinyl butyral resin sheet is preferable. The film thickness of these thermoplastic resin sheets is determined in consideration of the penetration resistance and the like required as a laminated glass, and is approximately the same as that of a conventional interlayer film, and particularly, 0.2 to 2 mm.
It is preferred that

[0015] At least one surface of the thermoplastic resin sheet has Ra of 3.5 to 7.0 µm and R
An emboss consisting of fine irregularities having an ab / Ra ratio of 15 to 25% in percentage is formed. To form such an emboss, an emboss roll method, a calendar roll method,
A profile extrusion method, an extrusion lip embossing method using melt fracture, and the like are employed. In particular, the embossing roll method is suitable for quantitatively obtaining embosses having constant fine irregularities.

The embossed concavo-convex pattern is not particularly limited as long as it satisfies the above specific conditions. In general,
Various fine uneven patterns composed of a large number of convex portions and a large number of concave portions with respect to these convex portions are formed, and these concave and convex patterns may be substantially and regularly distributed, and may be irregularly distributed. It may be regularly distributed. In addition, the height of each convex portion may be substantially the same height or different height, and the depth of each concave portion with respect to this convex portion is also substantially the same depth. May also be at different depths.

The shapes of the projections and the depressions are not particularly limited as long as they satisfy the specific conditions.
In general, pyramids such as triangular pyramids, square pyramids, and cones, truncated triangular pyramids,
It is composed of truncated pyramids such as truncated quadrangular pyramids and truncated cones, a number of convex portions formed of pseudo cones having a mountain-shaped or hemispherical head, and a number of concave portions corresponding to these convex portions. It is a concave and convex pattern,
In particular, a concavo-convex pattern composed of a large number of convex portions formed of a quadrangular pyramid, a mountain-shaped or a hemispherical pseudo-cone, and a large number of concave portions corresponding to these convex portions is preferable.

The dimensions of these embossed concavo-convex patterns are not particularly limited as long as they satisfy the above specific conditions. In general, the interval between the convex portions is approximately 100 to
Those having a size in the range of 2000 μm, particularly in the range of 150 to 1000 μm are preferred. In addition, the height of the protrusion is approximately 5
Those having a range of 500 µm, particularly 20 to 100 µm, are preferred. The length of the base of the protrusion (the diameter if the bottom is a circle) is preferably in the range of about 30 to 1000 μm. In particular, those having a ten-point average roughness (Rz) of 20 to 50 μm specified in JIS B0601 are preferable.

In the present invention, to measure Ra and Rab, a digital stylus electric surface roughness measuring instrument, for example, Feinpuff Perthen G of Germany.
Surface roughness meter manufactured by mbH (trade name: Performet)
er S3P) and this Perthometer S3
P-shaped surface profile analyzer (trade name: SAS-201)
0, manufactured by Meishin Koki Co., Ltd.).

Such Ra and Rab are closely related to the ease with which air is released during degassing and the ease with which the emboss is crushed during joining. In addition, there is a close relationship with the blocking resistance between the films. Therefore, as a result of various studies, if Ra is 3.5 to 7.0 μm and the ratio of Rab / Ra is 15 to 25% in percentage, the blocking resistance between the films during storage and the interlayer film between the glass plates are obtained. It was found that it was excellent in handling workability at the time of sandwiching, and also excellent in deaeration during preliminary pressure bonding.

The deaeration at the time of the pre-compression bonding is usually performed at 60 to 80 ° C. by the handling roll method, and at 60 to 100 ° C. by the decompression method.
When Ra is less than 3.5 μm under such pre-compression temperature conditions, the seal may be preceded and air may accumulate. Conversely, if Ra exceeds 7.0 μm, poor sealing tends to occur. Also, Rab /
If the Ra ratio is less than 15 in percentage, the blocking resistance becomes poor, and if the Rab / Ra ratio exceeds 25% in percentage, poor sealing tends to occur.

In the intermediate film of the present invention, it is preferable that both surfaces have the above-mentioned specific surface roughness, but only one surface has the above-mentioned specific surface roughness, and the other surface has the conventional surface roughness. May be formed with an embossment formed of fine irregularities. Thus, the interlayer film for laminated glass of the present invention is obtained.

In order to produce a laminated glass using the interlayer film of the present invention, the pre-compression bonding and the final compression bonding are performed in the same manner as in the usual production method of laminated glass. For example, when an intermediate film made of a plasticized polyvinyl butyral resin sheet is used, specifically, pre-compression bonding and main compression bonding are performed as follows.

That is, in the pre-compression bonding, an intermediate film is sandwiched between two transparent inorganic glass plates, and the laminate is passed through a nip roll, for example, under conditions of a pressure of about ^{2 to} 10 kg / cm ² and a temperature of about 50 to 80 ° C. Pre-compression bonding (handling roll method) while degassing by treating with the above, or placing the above-mentioned laminate in a rubber bag, connecting the rubber bag to the exhaust system, and
-750mmHg vacuum (absolute pressure 360 ~ 10mmHg)
The temperature is increased while the pressure is reduced by suction, and pre-compression bonding is performed at about 50 to 100 ° C. (vacuum bag method).

Next, the pre-pressed laminate is subjected to a conventional method using an autoclave or a press.
Temperature of about 120-150 ° C, about 10-15 kg / cm ²
This pressure is applied. Thus, a laminated glass is manufactured.

As the glass plate, not only an inorganic glass plate but also an organic glass plate such as a polycarbonate plate and a polymethyl methacrylate plate can be used. The laminated structure of the laminated glass may be not only a three-layer structure of a glass plate / interlayer / glass plate, but also a multilayer structure such as a glass plate / interlayer / glass plate / interlayer / glass plate. it can.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples and comparative examples of the present invention are shown below. (Examples 1 to 4 and Comparative Examples 1 to 4) <Preparation of Intermediate Film for Laminated Glass>
Press an engraving mill (mother mill) for forming a rough part,
By rotating the metal roll and the engraving mill, the concavo-convex pattern of the engraving mill is transferred to the metal roll, and then the engraving mill (mother mill) for forming a dense part is sequentially arranged in the axial direction of the metal roll in the arrangement unit of the concavo-convex pattern. After that, the embossing roll (negative type roll) was produced by transferring the concavo-convex pattern of each engraving mill to a metal roll by the same operation as described above.

In the above-mentioned engraving mill, the convex portions of the concavo-convex pattern are hemispherical and arranged substantially regularly, and seven types having different concavo-convex patterns (four types in Example, three types in Comparative Example 3) are used.
Kind) prepared.

On the other hand, 100 parts by weight of a polyvinyl butyral resin (average degree of polymerization: 1700, residual acetyl group: 1 mol%, butyralization degree: 65 mol%) were mixed with 40 parts by weight of triethylene glycol di-2-ethylhexanoate as a plasticizer. And 0.2 parts by weight of magnesium acetate as an adhesive force adjuster were mixed, and the mixture was melt-kneaded by an extruder and extruded into a sheet from an extrusion die to obtain a plasticized polyvinyl butyral resin sheet having a thickness of 0.76 mm. Molded.

Using the above various embossing rolls and plasticized polyvinyl butyral resin sheet, seven types in which many fine hemispherical irregularities are formed on both surfaces of the plasticized polyvinyl butyral sheet by the embossing roll method (Example 4)
Types and three comparative examples) interlayer film for laminated glass (PVB)
Film).

With respect to the interlayer films for laminated glass obtained in each of the above Examples and Comparative Examples, the arithmetic average roughnesses Ra and Rab were measured by the following method, and the Rab / Ra ratio was calculated as a percentage. Further, a blocking resistance test was performed to evaluate the handling workability and self-adhesion of the interlayer film. Further, a baking test was performed on each of the laminated glasses using these intermediate films by the following method, and the deaeration in the preliminary pressure bonding step was evaluated. The results are summarized in Tables 1 and 2.

(1) Arithmetic mean roughness Ra and Rab of interlayer
Measurement Feinpuf Perthen GmbH, Germany
Surface roughness meter (trade name: Perthometer)
S3P) and Ra (μm) and Rab (μm) specified in JIS B 0601 were measured using a surface shape analyzer (trade name: SAS-2010, manufactured by Meishinki Koki Co., Ltd.) of the Perthometer S3P specification. Note that R
a is a value when the cutoff value is 2.5 mm,
Rab is a value when the cutoff value is 0.08 mm.

(2) Blocking resistance test The intermediate film was cut into 15 cm × 15 cm, two of them were put on each other, and a 13 kg weight was placed thereon, left at room temperature for 24 hours, and then subjected to a tensile tester at 500 mm / min. A 180-degree peel test was performed at the above speed, and the self-adhesive force (g / 15 cm width) was measured (number of repetitions: 5). The smaller this self-adhesive power is,
Intermediate films are less likely to adhere to each other, and the handling workability during storage or when sandwiching the intermediate films between glass plates is excellent.

(3) Bake test (accelerated test) Preliminary pressure bonding was performed by the following method (handling roll method and vacuum bag method), and then final pressure bonding was performed to produce a laminated glass.

(A) Handling roll method The intermediate film is formed of two transparent float glass plates (length 30 cm ×
The portion protruding is cut out, and the laminate obtained in this manner is heated in an oven at a temperature (preliminary compression temperature) of 60, 7 respectively.
0, 80 ° C., then nip roll (air cylinder pressure 5 kg / cm ² , linear velocity 10 m
/ Min) for pre-compression bonding.

(B) Vacuum bag method The interlayer film is made of two transparent float glass plates (length 30 cm ×
(Weight 30 cm × thickness 3 mm), cut off the protruding part, transfer the thus obtained laminate into a rubber bag, connect the rubber bag to a suction decompression system, and heat at the outside air heating temperature and at the same time −600 mmHg (Absolute pressure 160m
The laminate was heated under reduced pressure (mHg) for 10 minutes, heated so that the temperature of the laminate (preliminary compression temperature) became 60, 70, and 100 ° C., respectively, and then returned to the atmospheric pressure to complete the preliminary compression bonding.

The laminate thus obtained is kept in an autoclave at a temperature of 135 ° C. and a pressure of 12 kg / cm ² for 20 minutes, and then the temperature is lowered to 50 ° C. and the pressure is returned to the atmospheric pressure to complete the final pressure bonding. Thus, a laminated glass was produced.

The laminated glass was heated in an oven at 145 ° C. for 2 hours, taken out of the oven and cooled for 3 hours assuming severe conditions, and foamed (bubbled) in the laminated glass.
The number of sheets in which occurred was examined, and the deaeration was evaluated. The number of test is 1
The number of foamed sheets at each pre-compression bonding temperature (number of foamed sheets / per 100 sheets) is shown as 00 sheets.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

As described above, in the interlayer film for laminated glass in which the embossment composed of fine irregularities is formed on both sides of the thermoplastic resin sheet, at least one surface of the embossment has a surface roughness Ra of 3.5-7. 0.0 μm and Rab /
By setting the Ra ratio to be 15 to 25% in percentage, it is excellent in blocking property during storage and handling workability when an intermediate film is sandwiched between glass plates, and also excellent in deaeration in the pre-compression bonding step. An interlayer for laminated glass is obtained.

Therefore, when a laminated glass is manufactured using such an interlayer film for a laminated glass, a laminated glass having a large area, a laminated glass having a large curvature, and a productivity of the laminated glass are increased. Even when degassing is performed sufficiently, the interlayer film is smoothly smoothed along the surface of the glass plate, and even when used under severe conditions, foaming does not occur. It is possible to efficiently produce a laminated glass having good adhesion, excellent transparency, and good quality.

By using the interlayer film for laminated glass, the deaeration in the pre-compression bonding step is excellent, and the pre-compression can be efficiently performed, regardless of whether the handling roll method or the reduced pressure bag method is employed.

Claims (1)

[Claims] 1. An interlayer film for laminated glass in which embosses having fine irregularities are formed on both surfaces of a thermoplastic resin sheet, the surface roughness of the emboss on at least one surface is Ra.
Is 3.5 to 7.0 μm, and the Rab / Ra ratio is 15 to 25% in percentage. Here, Ra and Rab are JIS B 060
Represents the arithmetic average roughness (μm) defined in 1, where Ra is a value when the cutoff value is 2.5 mm, and Rab is a value when the cutoff value is 0.08 mm.