JP2001048599A - Interliner for laminated glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a high-quality laminated glass free from Moire phenomenon in high workability generating little defective quality by forming a number of embossed dots on both surfaces of a thermoplastic resin sheet and interposing the sheet between a pair of glass plates wherein the arrangement and spaces of the dots of the embossed sheet are made to be different between the surfaces. SOLUTION: A number of embossed dots composed of small protrusions and recesses are formed on both surfaces of a thermoplastic resin sheet such as a plasticized polyvinyl butyral resin sheet, the embossed sheet is used as an interliner and placed between a pair of glass plates, the laminate is preparatorily pressed while removing air remaining between the glass plates and the interliner and pressed under heating in an autoclave to obtain a laminated glass. The space between the embossed dots is made to be different from each other between the surfaces and the space on one surface is preferably set to be >=1.25 times the space on the other surface. The development of Moire phenomenon is effectively suppressed by this process. Preferably, the deaeration efficiency is improved by forming the emboss to continue the bottom of the recess of the emboss on one or both surfaces or forming a linearly engraved embossed pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an interlayer film for laminated glass.

[0002]

2. Description of the Related Art An interlayer film for laminated glass formed by forming a plasticized thermoplastic resin such as a plasticized polyvinyl butyral resin between glass plates (hereinafter simply referred to as "intermediate film").
The laminated glass in which the glass is interposed, bonded and integrated is widely used as window glass for automobiles, aircraft, buildings and the like.

[0003] In this kind of laminated glass, usually, an interlayer is sandwiched between at least two glass plates and handled by passing through a nip roll (pressing roll) (handling deaeration method) or put in a rubber bag to reduce the pressure. It is manufactured by suction (vacuum degassing method), pre-press bonding while degassing the air remaining between the glass plate and the intermediate film, and then performing main press bonding by heating and pressurizing in an autoclave, for example.

The above-mentioned interlayer film has good basic performances such as transparency, adhesiveness, penetration resistance and weather resistance. In addition, the interlayer film does not block each other during storage, and the interlayer film has a gap between glass plates. It is required to have good handling workability at the time of sandwiching and to have good deaeration in the pre-compression bonding step in order to eliminate the generation of air bubbles due to entrainment of air.

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 fine unevenness include, for example, various uneven patterns including a large number of convex portions and a large number of concave portions corresponding to these convex portions, and a large number of convex portions and a large number of concave grooves for these convex portions. Various irregular patterns are disclosed.

[0006] In addition, the shape of the emboss is
Various shape factors such as arrangement and size have been studied. For example, Japanese Patent Publication No. 1-32776 discloses that "fine embossment made of a soft thermoplastic resin and used as an interlayer film for laminating and bonding". At least one surface of the film or sheet having the surface shape of (1) has a large number of independent protrusions integrally formed with the film or sheet, and all the recesses for the protrusions are continuously formed at the same level. And an intermediate film made of a thermoplastic resin.

However, an interlayer film having embosses regularly arranged on both sides as disclosed in the above disclosure has a stripe-like shape generally called "moire phenomenon" due to interference of diffraction surfaces. A diffraction image appears.

The above-mentioned moiré phenomenon is not only unfavorable from the viewpoint of appearance, but also causes the eyes of the operator to be tired due to the change of interference fringes and the like at the time of cutting the interlayer film or at the time of the work of alignment. There is a problem that symptoms such as motion sickness are caused, and as a result, workability is reduced. Further, even when the regularly arranged emboss is an intermediate film provided only on one side, the moiré phenomenon also appears when a plurality of sheets are stacked and worked.
Similarly, there is a problem that the workability is reduced.

The moiré phenomenon is more likely to appear as the arrangement and spacing of the embosses formed on the surface of the intermediate film are more regular. For example, the distance between at least two points of the projections of each emboss becomes constant. In such an arrangement, or when the emboss arrangement on both surfaces of the intermediate film is the same, a moire phenomenon appears in most cases.

Therefore, for example, an emboss formed in a lattice pattern, a striated pattern, a radial pattern having a spread at a certain interval, or the like can be said to be an example of a typical emboss in which the moire phenomenon easily appears.

In order to cope with the problem of the appearance of the moiré phenomenon and the reduction of workability, for example, Japanese Patent Application Laid-Open
Japanese Patent Application Laid-Open No. 294679/1990 discloses "a method of providing a large number of projections whose arrangement is defined on the surface of an intermediate film and irregularly applying embosses having finer projections than the projections".

However, according to the method disclosed in the above disclosure, although the appearance of the moire phenomenon is considerably improved, embossing having finer projections than projections is applied to the projection surface and the surface where the projections are not located. Therefore, there is a problem that air is trapped in the concave portion of the emboss having the fine convex portion, and the deaeration in the pre-compression bonding step becomes insufficient.

[0013]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to eliminate the occurrence of a moire phenomenon even when the emboss arrangement and intervals are regular. It is an object of the present invention to provide an interlayer film for laminated glass which is excellent and has excellent degassing properties in the pre-compression bonding step, and is therefore suitable for obtaining a high-quality laminated glass which hardly causes poor quality due to generation of bubbles.

[0014]

According to the present invention, there is provided an interlayer film for laminated glass, wherein a large number of embosses having fine irregularities are formed on both surfaces of a thermoplastic resin sheet. The emboss arrangement distance of the surface is different from the emboss arrangement distance of the other surface.

[0015] The interlayer film for laminated glass according to claim 2 is the interlayer film for laminated glass according to claim 1, wherein
The spacing between the embosses on one surface is 1.25 times or more the spacing between the embosses on the other surface.

According to a third aspect of the present invention, there is provided the interlayer film for laminated glass according to the first or second aspect, wherein the bottom side of the embossed concave portion on at least one surface is continuous. It is characterized by being.

According to a fourth aspect of the present invention, there is provided an interlayer film for laminated glass according to any one of the first to third aspects, wherein a pattern of the embossed concave portion on at least one surface is inscribed line shape. It is characterized by being formed.

The thermoplastic resin sheet used in the present invention includes, for example, a plasticized polyvinyl acetal resin sheet, a polyurethane resin sheet, an ethylene-vinyl acetate resin sheet, an ethylene-ethyl acrylate resin sheet, and a plasticized vinyl chloride. A thermoplastic resin sheet conventionally used for an intermediate film, such as a system-based resin sheet, may be mentioned, and is preferably used. These thermoplastic resin sheets are excellent in basic performance required as an interlayer such as adhesion, weather resistance, penetration resistance, and transparency.

Among the thermoplastic resin sheets, a plasticized polyvinyl acetal resin sheet represented by a plasticized polyvinyl butyral resin sheet is particularly preferably used.

The thickness of these thermoplastic resin sheets may be set in consideration of the penetration resistance and the like required as a laminated glass, and is not particularly limited. Preferably it is 0.2 to 2 mm.

The interlayer film for laminated glass of the present invention is an interlayer film in which a large number of embosses having fine irregularities are formed on both surfaces of the thermoplastic resin sheet. Is formed so as to be different from the emboss arrangement interval.

By forming the emboss arrangement interval on one surface of the intermediate film different from the emboss arrangement interval on the other surface, even when the emboss arrangement and interval are relatively regular. Thus, the appearance of the moire phenomenon can be effectively suppressed.

In general, the appearance of the moiré phenomenon is more likely to occur as the emboss arrangements and intervals on both surfaces of the interlayer are closer to each other. Therefore, by forming the arrangement interval of the emboss on one surface different from the arrangement interval of the emboss on the other surface, in other words, the arrangement interval of the emboss on one surface and the arrangement interval of the emboss on the other surface. By intentionally providing a difference between the two, it is possible to effectively suppress the appearance of the moire phenomenon even when the arrangement and the interval of the embossment on each surface are relatively regular.

In the present invention, the spacing between the embosses on one surface of the intermediate film is preferably 1.25 times or more, more preferably, the spacing between the embosses on the other surface. 1.3 times or more.

If the spacing between the embosses on one surface is less than 1.25 times the spacing between the embosses on the other surface, the effect of suppressing the appearance of the moire phenomenon may be insufficient.

In the present invention, it is preferable that the bottom of the embossed concave portion on at least one surface of the intermediate film is formed to be continuous.

By making the bottom of the embossed recess on at least one surface of the intermediate film continuous, the bottom of the embossed recess can be communicated and the deaeration in the pre-compression bonding step can be remarkably improved. Laminated glass is
It is of high quality with almost no poor quality due to the generation of bubbles.

Generally, the ease with which air is evacuated during degassing in the pre-compression bonding step is greatly affected by the continuity and smoothness of the bottom of the embossed concave portion, and has little effect on the arrangement and spacing of the embossed convex portions. I do not receive. Therefore, by making the bottom side of the embossed concave portion of at least one surface of the intermediate film continuous, the bottom side of the embossed concave portion communicates, and it is possible to effectively improve the degassing property in the preliminary pressure bonding step. As a result, it is possible to obtain a high-quality laminated glass that hardly causes poor quality due to the generation of bubbles.

Further, in the present invention, it is preferable that the pattern of the embossed concave portion on at least one surface of the intermediate film is formed so as to have a ruled line shape.

As the pattern of the embossed concave portion, a lattice shape, a radial shape, a hemispherical shape, and the like can be given in addition to the engraved line shape. The deaeration in the pressing step is further improved.

Examples of the method for forming a large number of embosses having fine irregularities on both surfaces of the thermoplastic resin sheet include known methods such as an emboss roll method, a calender roll method, and a profile extrusion method. An embossing roll method capable of forming a large number of embosses having quantitatively uniform fine irregularities is suitably employed.

As the embossing roll used in the embossing roll method, for example, a metal roll surface is subjected to blasting using an abrasive such as aluminum oxide or silicon oxide, and then vertical grinding is performed to reduce an excessive peak on the surface. A fine uneven pattern was formed on the roll surface by performing lapping, and a fine uneven pattern was formed on the roll surface by transferring the uneven pattern to a metal roll surface using an engraving mill (mother mill). And those in which a fine uneven pattern is formed on the roll surface by etching (etching).

The embossed concavo-convex pattern may be any pattern as long as it satisfies the conditions specified in the present invention, and may be distributed regularly and regularly, or may be randomly and irregularly distributed. Although it may be distributed, it is generally preferable that the main embossed protrusions are regularly distributed. In addition, the height of the projections of each emboss may be the same or different, and the depths of the depressions corresponding to these projections are also the same. Or different depths.

The shape of the convex and concave portions of the emboss may be any shape as long as it satisfies the conditions specified in the present invention, and is not particularly limited. From pyramids such as triangular pyramids, quadrangular pyramids and cones, truncated triangular pyramids, truncated quadrangular pyramids, truncated cones such as truncated cones, pseudo pyramids with a mountain-shaped or hemispherical head Many convex parts,
It is preferable that the projections and depressions have a number of depressions corresponding to these projections.

Further, the dimensions of the convex and concave portions of the emboss are
Any size may be used as long as it satisfies the conditions specified in the present invention, and is not particularly limited. Generally, the interval between the convex portions is 10 to 2000 μm.
And more preferably 50 to 1
000 μm. The height of the convex portion is 5 to 50.
0 μm, more preferably 2 μm.
The range is from 0 to 100 μm. Furthermore, it is preferable that the length of the base of the convex portion is in the range of 30 to 1000 μm.

The method for producing a laminated glass using the interlayer film for a laminated glass according to the present invention is not particularly limited, and an intermediate film is formed between at least a pair of glasses in the same manner as in a normal laminated glass production method. After sandwiching and first performing preliminary pressure bonding to perform deaeration and temporary bonding, for example, by performing full pressure bonding in an autoclave, a desired laminated glass can be obtained.

In the case where a laminated glass is produced using an intermediate film made of, for example, a plasticized polyvinyl butyral resin sheet as the interlayer film for a laminated glass according to the present invention, the pre-compression bonding and the final compression bonding are specifically performed as follows. Do.

That is, in the pre-compression bonding, for example, an interlayer film for laminated glass according to the present invention is sandwiched between two transparent inorganic glass plates, and the laminate is passed through a nip roll (pressing roll). cm ² , temperature about 50
A method of pre-compression bonding while handling and degassing under conditions of １００100 ° C. (handling deaeration method), or placing the above-mentioned laminate in a rubber bag and connecting the rubber bag to an exhaust system to about −400 to −7
Decompression degree of 50 mmHg (absolute pressure 360 to 10 mmH
g), a method of raising the temperature while reducing the pressure by suction and pre-compression bonding at a temperature of about 50 to 100 ° C. (a vacuum degassing method) or the like is adopted.

Next, the pre-pressed laminate is used in an ordinary manner by an autoclave or a press.
For example, a temperature of about 120 to 150 ° C. and a pressure of about 2 to 15 kg
/ Cm ^{2 under} the condition of final compression bonding 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 a normal three-layer structure of glass plate / intermediate film / glass plate, but may be a multilayer structure of glass plate / intermediate film / glass plate / intermediate film / glass plate, for example. It may be.

[0041]

The interlayer film for laminated glass according to the present invention is an interlayer film for laminated glass in which a large number of embosses having fine irregularities are formed on both surfaces of a thermoplastic resin sheet. Since the arrangement intervals of the embosses on the surfaces are different from each other, that is, since there is a conscious difference between the arrangement intervals of the embosses on one surface and the arrangement intervals of the embosses on the other surface, Even when the arrangement and the intervals of the embossments are regular, the appearance of the moire phenomenon does not occur, and therefore, the workability at the time of cutting or joining processing is improved.

Further, by forming an emboss such that the emboss arrangement interval on one surface is 1.25 times or more as large as the emboss arrangement interval on the other surface, the effect of suppressing the moiré phenomenon is further improved. .

Further, by forming an emboss such that the bottom of the embossed concave portion on at least one surface is continuous, the bottom of the embossed concave portion communicates with the embossed concave portion. Become. Therefore, the obtained laminated glass is of high quality with almost no quality defects due to the generation of bubbles.

Further, by forming the embossment such that the pattern of the embossed concave portion on at least one surface is inscribed line shape, the above-described effect of improving the degassing property is further improved.

[0045]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 To 100 parts by weight of a polyvinyl butyral resin (average degree of polymerization: 1700, residual acetyl group: 1 mol%, butyralization degree: 65 mol%), triethylene glycol di-2-ethyl butyrate was used as a plasticizer. The mixture was melt-kneaded with an extruder and extruded into a sheet form from an extrusion die to form a mixture having a thickness of 0.1 part.
A 76 mm polyvinyl butyral resin sheet (PVB sheet) was obtained.

An engraving mill (mother mill) for forming an emboss having a line-shaped embossed pattern (uneven pattern) is pressed against the surface of one of the pair of embossed rolls.
By rotating the metal roll and the engraving mill, the embossed pattern of the engraving mill was transferred to the metal roll. Then
The engraving mill is sequentially moved in the axial direction of the metal roll in an array unit of the embossing pattern, and the embossing pattern of the engraving mill is transferred to the metal roll by the same operation as above, so that the engraved embossed pattern is regularly formed. The formed embossing roll was manufactured. The spacing between the embosses of the engraving mill was 250 μm.
m.

Further, an engraving mill (mother mill) having a scored embossed pattern is pressed against the surface of the other metal roll of the pair of embossing rolls, and the metal roll and the engraving mill are rotated. The embossed pattern was transferred to a metal roll. Next, the engraving mill is sequentially moved in the axial direction of the metal roll in the arrangement unit of the embossing pattern, and the embossing pattern of the engraving mill is transferred to the metal roll by the same operation as described above, so that the engraved line-shaped embossing pattern is regular. An embossed roll formed in a uniform manner was manufactured. The embossing interval of the engraving mill was 320 μm.

The PVB sheet obtained above (0.76 m
m thickness) is passed through the pair of embossing rolls obtained above, and a ruled embossed pattern is regularly formed on both surfaces,
In addition, an interlayer film for laminated glass was manufactured in which the emboss arrangement interval on one surface and the emboss arrangement interval on the other surface were different.

(Example 2) The emboss arrangement interval of one engraving mill (mother mill) was set to 300 μm, and the emboss arrangement interval of the other engraving mill (mother mill) was set to 375 μm.
In the same manner as in Example 1 except that m was used, a ruled embossed pattern was regularly formed on both surfaces, and the embossing arrangement interval on one surface and the embossing arrangement interval on the other surface were used. And a different interlayer film for laminated glass was manufactured.

(Example 3) The emboss arrangement interval of one engraving mill (mother mill) was set to 300 μm, and the emboss arrangement interval of the other engraving mill (mother mill) was set to 430 μm.
In the same manner as in Example 1 except that m was used, a ruled embossed pattern was regularly formed on both surfaces, and the embossing arrangement interval on one surface and the embossing arrangement interval on the other surface were used. And a different interlayer film for laminated glass was manufactured.

FIG. 1 schematically shows embossed patterns (irregular patterns) on the front, back and cross sections of the interlayer films for laminated glass obtained in Examples 1 to 3.

(Comparative Example) Both engraving mills (mother mills)
In the same manner as in Example 1 except that the embossing arrangement interval was set to 300 μm, a ruled embossed pattern was regularly formed on both surfaces, and the embossing arrangement interval on both surfaces was the same. An interlayer for glass was manufactured.

FIG. 2 shows an embossed pattern (concavo-convex pattern) on the front surface, the back surface and the cross section of the interlayer film for laminated glass obtained in the comparative example.
Is schematically shown.

With respect to the four types of intermediate films obtained in Examples 1 to 3 and Comparative Example, the average surface roughness (Rz) and average arrangement interval (Sm) of the emboss on each surface were measured by the following methods. The results were as shown in Table 1.

[Measurement of Rz] A conical stylus (tip radius: 5 μm, radius:
Using an apex angle of 90 °), the ten-point average surface roughness {Rz (μm)} of the emboss on each surface of the intermediate film was measured according to JIS B-0601.

[Measurement of Sm] Observing with a microscope, the average arrangement interval ΔSm (μm)
m)｝ was measured.

The presence or absence of the moire phenomenon was evaluated for the above four types of intermediate films by the following method. The results were as shown in Table 1.

[Presence of Moiré Phenomenon] While the intermediate film was slowly and continuously moved, it was visually observed to confirm the presence of moiré phenomenon.

Next, using each of the above four types of interlayer films, pre-compression bonding is performed by the following two methods (handling deaeration method and reduced pressure deaeration method), and then main compression is performed to perform the four types of interlayer bonding. A laminated glass was produced.

(A) Handling and deaeration method The interlayer film is formed of two transparent float glass plates (length 30 cm ×
30 cm wide x 3 mm thick), cut off the protruding part, and in a heating oven, the obtained laminate was heated at a temperature (preliminary compression temperature) of 60 ° C, respectively.
After heating to 70 ° C. and 80 ° C., pre-press bonding was performed by passing through a nip roll (air cylinder pressure 3.5 kg / cm ² , linear velocity 10 m / min).

(B) Vacuum degassing method The interlayer film is formed 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 temperature was maintained for 10 minutes under a reduced pressure of mHg), and the laminate was heated so that the temperature (preliminary pressure bonding temperature) became 60 ° C., 80 ° C., and 100 ° C., respectively, and then 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 maintaining the temperature at 0 ° C. and the pressure of 13 kg / cm ² 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.

Each of the four types of laminated glass obtained above was subjected to a bake test by the following method to evaluate the deaeration in the preliminary press bonding step. The results were as shown in Table 1.

[Bake test of laminated glass] The laminated glass 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 was evaluated. Note that the number of test sheets was 100 each.

[0066]

[Table 1]

As is clear from Table 1, none of the interlayer films for laminated glass of Examples 1 to 3 according to the present invention exhibited the moire phenomenon. This indicates that the workability at the time of cutting and laminating was good. Further, the laminated glass of Examples 1 to 3 produced using the above intermediate film was subjected to the baking test for both the pre-compression temperature in the handling deaeration method and the pre-compression temperature in the vacuum deaeration method. The number of foams (defective number) due to air bubbles was small. This indicates that the deaeration in the preliminary pressure bonding step was excellent.

On the other hand, the interlayer film for a laminated glass of the comparative example manufactured using a pair of embossing rolls manufactured by two engraving mills (mother mills) having the same embossing arrangement interval (300 μm) is used as a preliminary. Although the deaeration in the pressing step was excellent, the appearance of a moire phenomenon was observed. This indicates that the workability at the time of the cutting or the joining processing was poor.

[0069]

As described above, the interlayer film for laminated glass according to the present invention has no appearance of the moire phenomenon even when the arrangement and the interval of the emboss are regular. Therefore, workability at the time of cutting or joining processing is good. Further, since it is excellent in deaeration in the pre-compression bonding step, it is suitable for obtaining a high-quality laminated glass in which almost no defective quality due to generation of air bubbles occurs. Therefore, the laminated glass produced using the above intermediate film is of high quality and is suitably used as a window glass of an automobile, a vehicle, an aircraft, a building or the like.

[0070]

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embossed pattern of an interlayer film for laminated glass of Examples 1 to 3.

FIG. 2 is a schematic view showing an embossed pattern of an interlayer film for laminated glass of a comparative example.

Claims (4)

[Claims] 1. In a laminated glass intermediate film in which a large number of embosses having fine irregularities are formed on both surfaces of a thermoplastic resin sheet, an emboss arrangement space on one surface and an emboss arrangement space on the other surface are determined. Are formed so as to be different from each other. 2. The laminated glass according to claim 1, wherein the spacing between the embosses on one surface is formed to be at least 1.25 times the spacing between the embosses on the other surface. For intermediate film. 3. The interlayer film for laminated glass according to claim 1, wherein a bottom side of the embossed concave portion on at least one surface is formed to be continuous. 4. The interlayer film for laminated glass according to claim 1, wherein the pattern of the embossed concave portion on at least one surface is formed to have a ruled line shape.