JP2002104846A - Intermediate membrane for clad glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intermediate membrane for a clad glass enabling an easier temperature control at the beginning of venting gas in the manufacturing of the clad glass, with no necessity of too much elevating the temperature of heating for sealing the periphery parts. SOLUTION: This intermediate membrane for a clad glass is a thermoplastic resin sheet having embossed patterns comprising depression and projection on both surfaces, the depression part of which is formed of a sunken trench having a curvature R of 20 μm or larger at the bottom of the trench formed by the cross-section of the deepest end.

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 embossed pattern comprising fine concave portions and convex portions is formed.

[0002]

2. Description of the Related Art An interlayer made of a thermoplastic resin sheet such as plasticized polyvinyl butyral is sandwiched between glass plates.
Laminated glass obtained by bonding to each other is widely used for window glasses of automobiles, aircraft, buildings, and the like.

In such a laminated glass, usually, an intermediate film is sandwiched between glass plates and handled by passing through a nip roll or put in a rubber bag and suctioned under reduced pressure to remain between the glass plate and the intermediate film. Pre-crimp while removing air,
Next, it is manufactured by heating and pressurizing in an autoclave to perform main pressure bonding.

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. , To further eliminate air entrapment,
Good deaeration in the pre-compression bonding step is required.

In order to satisfy such demands, an embossed pattern having fine irregularities is usually formed on both surfaces of the intermediate film. As the fine uneven shape, for example, various uneven shapes including a large number of convex portions and concave portions corresponding to the convex portions, or various uneven shapes including a large number of convex portions and concave grooves corresponding to the convex portions are disclosed. As the embossed pattern, a pattern having various roughness, arrangement, size, etc., a groove-shaped or mountain-shaped pattern having a volume larger than a cone or a triangular pyramid, and the like are disclosed (for example, Japanese Patent Application Laid-Open No. 9-508
078, Japanese Patent Application No. 11-342172).

[0006] However, in the above-mentioned embossed pattern, although the initial temperature of the rubber bag can be increased particularly in the deaeration step by the vacuum deaeration method, the ultimate temperature also needs to be increased. There was a problem that air infiltration occurred and foamed.

[0007]

SUMMARY OF THE INVENTION In view of the above, the present invention makes it possible to easily control the temperature at the start of the initial degassing when manufacturing a laminated glass, and to reduce the heating temperature for sealing the peripheral part. An object of the present invention is to provide an interlayer film for laminated glass that does not need to be raised more than necessary.

[0008]

The present invention relates to an interlayer film for laminated glass having an embossed pattern comprising concave portions and convex portions provided on both surfaces of a thermoplastic resin sheet, wherein the embossed pattern has a concave groove. And the concave groove is
This is an interlayer film for laminated glass in which the radius of curvature R at the end of the concave bottom formed by the cross section at the deepest portion is 20 μm or more. Hereinafter, the present invention will be described in detail.

The interlayer film for laminated glass of the present invention (hereinafter also referred to as an interlayer film) is a thermoplastic resin sheet having embossed patterns formed of concave portions and convex portions on both surfaces.
The thermoplastic resin sheet is not particularly limited, and for example, those conventionally used for interlayer films for laminated glass are used. For example, plasticized polyvinyl acetal resin sheets, polyurethane-based resin sheets, and ethylene-vinyl acetate-based sheets are used. Resin sheets, ethylene-ethyl acrylate-based resin sheets, plasticized vinyl chloride-based resin sheets, and the like are included. These sheets have good adhesion, weather resistance, penetration resistance,
Excellent in basic performance required for laminated glass such as transparency.

Among them, a plasticized polyvinyl acetal resin sheet represented by a plasticized polyvinyl butyral resin sheet is preferably used. The thickness of the thermoplastic resin sheet is determined in consideration of the penetration resistance and the like required for the laminated glass, and may be about the same as that of a conventional interlayer. Preferably it is.

In the intermediate film of the present invention, the embossed pattern is such that a concave portion is formed by a concave groove. Generally, in the pre-compression bonding step, the ease with which air remaining when degassing the air remaining between the glass plate and the intermediate film is determined by the continuity and smoothness of the grooves among the embossed patterns. It is known that the relationship is closely related only to the distance between the projections and not so much to the spacing and arrangement of the projections.

On the other hand, it is known that the volume of the convex portion of the embossed pattern and the cross-sectional shape of the concave groove greatly influence the crushability of the embossed pattern in the pre-compression bonding step. The volume of the convex portion of the embossed pattern is determined by the interval and arrangement of the convex portions and the width of the convex portion, and the volume of the convex portion increases as the width of the convex portion increases. Also, the roughness of the embossed pattern can be reduced by setting the width of the convex portion large.

In the intermediate film of the present invention, the radius of curvature R at the end of the bottom of the concave formed by the cross section at the deepest part of the concave groove is 20 μm or more. When the radius of curvature R is less than 20 μm, the concave groove formed in the intermediate film is too narrow, and the emboss pattern is less likely to be crushed in the preliminary pressure bonding step. It is preferably from 40 to 100 μm, and more preferably from 50 to 100 μm. If it exceeds 100 μm, the anti-seal property of the seal deteriorates, that is, the seal failure occurs due to the high initial back temperature, which is not preferable. In the present specification, the end of the bottom of the concave shape refers to a concave inflection point, and the radius of curvature R is:
Surface roughness meter manufactured by Feinpuf Perthen GmbH, Germany (trade name: Perthometer S
3P) and can be read from a two-dimensional chart obtained with a measurement length of 2.5 m using a surface shape analyzer (trade name: SAS-2010, manufactured by Meishinki Koki Co., Ltd.) of the Perthometer S3P specification. Yes,
This value is obtained by calculating the radius of curvature of a portion clearly forming a groove from the two-dimensional chart and calculating the average value of n = 5.

In general, the cross-sectional shape of the embossed groove is V-shaped, U-shaped, U-shaped, or the like. In the present invention, the groove is U-shaped or U-shaped. It is preferably in the shape of a letter. If the groove has a V-shaped cross section, the adhesiveness between the intermediate film and the glass plate is reduced, and there is a possibility that sealing failure may occur.

The intermediate of the present invention has a surface roughness of 0 <R _vk
/ R _Z ≦ 0.35 and Mr ₂ ≧ 85% (where R _Z
Is the ten-point average roughness (μm) specified in DIN 4768.
m), R _vk represents the reduced valley depth (μm) obtained from the Abbott load curves defined in DIN 4762 and 4776, and Mr ₂ represents the material component (%) obtained from the Abbott load curves. ) Is preferable.

The above-mentioned Abbott load curve is obtained by measuring the surface roughness of an embossed sheet using a surface roughness meter to obtain, for example, a roughness curve as shown in FIG. Length ratio [(bearing ratio
tp = material component (ma
2) is obtained. For example, as shown in FIG. 2, a curve obtained by expressing the load length ratio (%) on the horizontal axis and the cutting level (%) on the vertical axis as shown in FIG. Thus, it represents the cumulative probability distribution of the surface roughness.

[0017] Here, the load length ratio (%) is evaluated from a roughness curve in the direction of its average line length (l _m) periodically sampled, parallel roughness curve of the sampled portion relative to the peak line Profile section level
the sum of the cut length obtained upon digestion with vel) of (load _{length) (b 1 + b 2 +} b 3 + ... + b n), in which the ratio, expressed as a percentage of the evaluation length (l _m) . Note that the cutting level is set to 0 at the peak level of the roughness curve.
%, The valley bottom line of the roughness curve being the cutting level 100% (see DIN 4762 and 4776).

The Abbott load curve two-dimensionally represents the average shape of the emboss. As shown in FIG. 3, the position of the cutting line (profile section) is used.
material component Mr as a function of lineposition (μm)
Represented by (%), three regions _{(R k, R pk, R} vk) is divided into. Here, R _k (μm) is the central region of the roughness,
_pk (μm) represents the converted peak height (average height of the peak protruding from the central region), R _vk (μm) represents the converted valley height (average height of the valley portion falling from the central region), Mr
₁ (%) represents a material component (proportion of a peak portion), and Mr ₂ (%) represents a material component (proportion of a portion excluding a valley portion).

In order to measure the surface roughness parameters (R _Z , R _vk , Mr _2, etc.) of the embossed sheet, for example, Feinpuff Perthen GmbH, Germany
Surface roughness meter manufactured by Company H (trade name: Perthometer)
S3P) and this Perthometer S3
P specification surface shape analyzer (trade name: SAS-201)
0, manufactured by Meishin Koki Co., Ltd.).

In such an Abbott load curve, R
_vk (converted valley depth (μm), that is, the average height of the valley portion falling from the center region) is an air passage in the pre-compression bonding step between the glass plate and the intermediate film. Has a close relationship with the ease with which air can escape. Also, Mr
₂ (Material component (%), that is, the ratio of the portion excluding the valley portion) is not only a resistance to the movement of air, but also has a close relationship with the crushability of the embossed pattern during laminated glass processing.

As a result of various studies, the present inventors have found that 0 <R
By satisfying the relations of _vk / R _Z ≦ 0.35 and Mr ₂ ≧ 85%, it was found that an intermediate film having excellent degassing property at the time of preliminary press bonding was obtained. R _vk / R _Z is 0.3
Beyond that, the depth of the groove becomes extremely deep, easily air is trapped in the part during the degassing, R _vk
An embossed pattern with / R _Z of 0 is not preferable because it is actually difficult to form and locally degassed.
Further, when Mr ₂ is less than 85%, the width of the concave groove becomes very large, so that a large amount of air tends to remain in this portion, and further, the convex portion is easily crushed before reaching the pre-press bonding condition. In addition, the deaeration in the pre-compression bonding step tends to be insufficient.

The embossed pattern in the present invention is not particularly limited as long as it satisfies the above requirements. In general, an embossed pattern is composed of various fine irregularities including a large number of convex portions and a large number of concave grooves for these convex portions, and these irregularities may be regularly and regularly distributed, It may be irregularly distributed. In general, it is preferable that the convex portions having the main concave-convex shape are arranged regularly.

The main embossed pattern of the present invention is not particularly limited as long as it satisfies the above requirements. In general, the main concavo-convex shape is a pyramid such as a triangular pyramid, a square pyramid, or a cone; a truncated pyramid such as a truncated triangular pyramid, a truncated square pyramid, or a truncated cone; It is composed of a number of convex portions such as cones and a number of concave portions corresponding to these convex portions.

In the present invention, the height of each projection may be the same or different, and the depth of each groove with respect to this projection is also the same. May also be at different depths. It is preferable that the concave groove in the present invention is formed continuously. When formed continuously, when the air remaining between the glass plate and the intermediate film is degassed in the pre-compression bonding step, the air is easily released.

The dimensions of the concave and convex portions of the embossed pattern in the present invention are not particularly limited as long as the requirements described above are satisfied. Generally, the interval between the convex portions is approximately 10 to 2000.
μm, preferably 200 to 1000 μm
Is more preferable. The height of the projections is preferably in the range of about 5 to 500 μm, preferably 2 to 500 μm.
More preferably, it is in the range of 0 to 100 μm. It is preferable that the length of the base of the convex portion is approximately in the range of 30 to 1000 μm.

The method for forming such an embossed pattern is not particularly limited, and examples thereof include an embossing roll method, a calendering roll method, a profile extrusion method, and an extrusion lip embossing method using a melt fracture. Among them, the embossing roll method is preferable because an embossed pattern having a constant fine unevenness can be obtained quantitatively.

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 ordinary production method of laminated glass. For example, when an intermediate film made of a plasticized polyvinyl acetal resin sheet is used, specifically, the following pre-compression bonding and main compression bonding are performed.

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, at a pressure of about 0.2 to 1 MPa and a temperature of about 50.
A method of pre-compression bonding while handling and degassing under conditions of ~ 80 ° C (handling degassing method), or placing the above-mentioned laminate in a rubber bag and connecting a rubber bag to an exhaust system to about -53.2 to- 9
9.8 kPa vacuum (absolute pressure 47.9 to 1.33 kP
a) Raise the temperature while reducing the pressure by suction to about 50-100 ° C.
(Pressure-reducing degassing method).

Next, the pre-pressed laminate is subjected to main-press bonding at a temperature of about 120 to 150 ° C. and a pressure of about 1 to 1.5 MPa using an autoclave or a press according to a conventional method. Is manufactured.

As the above-mentioned 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 is as follows: glass plate / interlayer /
Not only a three-layer configuration of a glass plate but also a multilayer configuration such as a glass plate / interlayer / glass plate / interlayer / glass plate can be used.

[0031]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

(Examples 1 to 3, Comparative Examples 1 and 2) As shown in Table 1, a metal having a main projection shape, a radius of curvature R of the projection portion (represented by R in FIG. 4) and a concave groove shape. An embossing roll was prepared, and a polyvinyl butyral film (“DXN film” manufactured by Sekisui Chemical Co., Ltd., Ra ≧ 3 μm) was passed between the embossing roll and the rubber roll heated to 130 ° C. to form an embossed pattern. An interlayer for glass was obtained. A groove having a cross-sectional shape as shown in FIG. 7 is formed in the intermediate film of the example, and the intermediate film of the comparative example has a groove shown in FIG.
A concave groove having a sectional shape as shown in FIG.

With respect to the interlayer film for laminated glass obtained in each of the examples and comparative examples, the parameters (R _Z , R _vk , Mr ₂ ) of the surface roughness of the embossed pattern were measured by the following method. Are shown in Table 1. Further, after a laminated glass was produced using the interlayer film for a laminated glass, a bake test was performed to evaluate the deaeration in the pre-compression bonding step. The results are shown in Table 1.

(1) Concavo-convex Shape of Embossed Pattern The pitch a of the convex portion, the width b of the convex portion, and the width c of the concave portion of the embossed pattern (all shown in FIGS. 5 and 6) were measured by an electron micrograph.

(2) Measurement of the parameter of the surface roughness of the embossed pattern Feinpuff Perthen GmbH, Germany
Surface roughness meter (trade name; Perthometer)
S3P), and the surface shape analyzer (trade name of this PerthometerS3P specification; SAS-2010, using a Akinobu Koki Co., Ltd.), the intermediate layer R _Z ([mu] m), R
_vk (μm) and Mr ₂ (%) were measured.

(3) Bake test The intermediate film was made of two transparent float glass plates (length 30 cm ×
It was sandwiched between (width 30 cm × thickness 3 mm) and the protruding portion was cut out to produce a laminate. The obtained laminate was transferred into a rubber bag, and the rubber bag was connected to a suction decompression system, heated at the outside air heating temperature, and simultaneously held at -79.8 kPa (absolute pressure: 21.3 kPa) for 10 minutes under reduced pressure. The body temperature (pre-compression temperature) is 55 ° C, 65 ° C, 7
After heating to 5 ° C., the pressure was returned to atmospheric pressure, and the preliminary pressure bonding was completed.

The laminate thus obtained was placed in an autoclave at a temperature of 140 ° C. and a pressure of 1.3 MPa for 10 minutes.
After holding for 5 minutes, the temperature was lowered to 50 ° C., and the pressure was returned to the atmospheric pressure to complete the final pressure bonding, thereby producing a laminated glass.

The laminated glass was heated in an oven at 140 ° C. for 2 hours, taken out of the oven, and cooled for 3 hours.
The number of foams (bubbles) generated in the laminated glass was examined, and the deaeration was evaluated. The number of test pieces was 100, and the smaller the number of foamed pieces, the better the deaeration.

[0039]

[Table 1]

[0040]

Since the present invention has the above-described structure, the air interposed between the glass plate and the intermediate film is smoothly discharged in the relatively low-temperature pre-compression bonding step in which the temperature can be easily controlled, and the air can be sufficiently removed. This makes it possible to obtain an interlayer film for laminated glass that has good adhesion between the glass plate and the interlayer film and excellent transparency.

[Brief description of the drawings]

FIG. 1 is a graph showing an example of a roughness curve of an embossed pattern.

FIG. 2 is a graph showing an example of an Abbott load curve having an embossed pattern and showing a relationship between a cutting level and a load length ratio.

FIG. 3 is a graph showing an example of an Abbott load curve of an embossed pattern and showing a relationship between a position of a cutting line and a material component.

FIG. 4 is an explanatory view partially showing an example of an embossing roll.

FIG. 5 is a perspective view schematically showing an embossed pattern.

FIG. 6 is a schematic view of an embossed pattern viewed from above.

FIG. 7 is an explanatory view partially showing a concave groove of an interlayer film for laminated glass of an example.

FIG. 8 is an explanatory view partially showing a concave groove of an interlayer film for laminated glass of a comparative example.

Claims (2)

[Claims] 1. An interlayer film for laminated glass having an embossed pattern comprising concave portions and convex portions provided on both surfaces of a thermoplastic resin sheet, wherein the embossed pattern has a concave portion formed by a concave groove. The groove has a radius of curvature R of 20 μ at the end of the bottom of the concave formed by the cross section at the deepest part.
m or more. 2. The surface roughness is 0 <R _vk / R _Z ≦ 0.3.
5, and Mr ₂ ≧ 85% (where R _Z is DIN 4
Represents the ten-point average roughness (μm) specified in 768, and R _vk
Represents the reduced valley depth (μm) obtained from the Abbott load curves defined in DIN 4762 and 4776,
The intermediate film for laminated glass according to claim 1, wherein r ₂ satisfies a relationship of a material component (%) obtained from the Abbott load curve.