JP3201778B2 - Interlayer for laminated glass and laminated glass using the same - Google Patents

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 which is particularly suitable for producing a laminated glass having a large curvature, and a laminated glass using the same.

[0002]

2. Description of the Related Art Plasticized polyvinyl butyral sheets are
As an interlayer film of laminated glass, it is widely used for window glasses of automobiles, aircraft, buildings, and the like.

[0003] This kind of plasticized polyvinyl butyral sheet is generally produced by mixing a polyvinyl butyral resin with a plasticizer such as triethylene glycol di-2-ethyl butyrate and melt-extruding it into a sheet.

[0004] Incidentally, polyvinyl butyral resins generally have a butyralization reaction at a relatively low temperature (0 to 0).
Polyvinyl butyral resin synthesized by a precipitation method (using an aqueous medium) performed at -30 ° C) is used. The reason is that the precipitation method using this aqueous medium is industrially advantageous because there is no need to recover an expensive solvent as compared with the solution method.

[0005] In order to manufacture a laminated glass using such a plasticized polyvinyl butyral sheet as an intermediate film, an intermediate film is sandwiched between two glass plates, and this is put in, for example, a rubber bag while sucking under reduced pressure. Generally, 70
After pre-adhesion at ~ 110 ° C, 120 ~ 1 in autoclave
The actual bonding is performed at 50 ° C. and a pressure of about 10 to 15 kg / cm ² .

[0006]

Recently, laminated glass having a three-dimensionally curved surface with a large curvature has come to be used as a windshield of an automobile because of the emphasis on high-speed performance and the tendency to increase in size.

However, when manufacturing a laminated glass having a large curvature using a conventional laminated glass interlayer made of a plasticized polyvinyl butyral sheet, air (bubbles) is interposed between the interlayer and the curved surface portion of the glass plate. Defects tend to remain.

For this reason, during the production of laminated glass, it is necessary to absorb or remove the residual air in the film by rework such as repeated pressurization, which is troublesome. Further, in some cases, the residual air may not be removed by rework, and such a product is discarded, so that there is a problem that the product efficiency is reduced.

The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to efficiently obtain a laminated glass of good quality without residual air even when producing a laminated glass having a large curvature. It is an object of the present invention to provide an interlayer film for laminated glass which can be used and a laminated glass provided with the interlayer.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to provide an intermediate film for laminated glass as a melt viscosity at 140 ° C. using a Koka type flow tester (nozzle diameter 1 mm, nozzle length 1 mm, plunger pressure 20 kg / cm ² ). Is less than 6 × 10 ⁴ poise and 11
This can be achieved by using a plasticized polyvinyl acetal sheet having a melt viscosity at 0 ° C. of 2 × 10 ⁶ poise or more.

The interlayer film for laminated glass of the present invention is produced by mixing a plasticizer with a polyvinyl butyral resin and melt-extruding the mixture into a sheet or by a calendering method or a pressing method. At this time, the sheet surface may be embossed. Polyvinyl butyral resin is produced by a condensation reaction between polyvinyl alcohol and butyraldehyde.

Examples of the plasticizer include triethylene glycol di-2-ethyl butyrate, triethylene glycol di-2-ethylhexoate, triethylene glycol dicaprylate, triethylene glycol di-n-heptoate, and tetraethylene glycol. Di-n-heptoate and the like are preferably used.

Such a plasticizer is generally mixed in an amount of 30 to 60 parts by weight with respect to 100 parts by weight of the polyvinyl acetal resin. When the content of the plasticizer is less than 30 parts by weight, the penetration resistance of the laminated glass decreases. Conversely, if the content of the plasticizer exceeds 60 parts by weight, the plasticizer seeps out and adversely affects the transparency of the laminated glass.

A conventional adhesion regulator comprising an organic acid salt of an alkali metal or alkaline earth metal such as magnesium acetate may be mixed with the plasticizer. Generally, about 0.01 to 0.5 parts by weight of such an adhesion modifier is blended with respect to 100 parts by weight of the resin. Further, such an adhesion regulator may be applied as a solution to the surface of the plasticized polyvinyl butyral sheet and dried. In addition, known additives such as a colorant and an ultraviolet absorber used in the interlayer film for laminated glass can be blended.

The plasticized polyvinyl butyral sheet thus obtained has a melt viscosity of 6 × 10 ^{4 at} 140 ° C. by a Koka type flow tester (nozzle diameter: 1 mm, nozzle length: 1 mm, plunger pressure: 20 kg / cm ² ). Less than poise and 11
The melt viscosity at 0 ° C. is set to 2 × 10 ⁶ poise or more.

140 of plasticized polyvinyl butyral sheet
If the melt viscosity at 0 ° C. is higher than 6 × 10 ⁴ poise, the fluidity of the film at the time of final adhesion to a glass plate is poor, and air may remain. Also, if the melt viscosity at 110 ° C is lower than 2 × 10 ⁶ poise, the membrane at room temperature will be sticky, and the membranes will stick together during storage and work, and the membrane will be sucked during superposition. Troubles occur, such as not being performed smoothly. In addition, the edge of the membrane is sealed first, so that it is difficult for air to escape.

A conventional plasticized polyvinyl butyral sheet of this type is produced by an advanced type flow tester (nozzle diameter 1 mm, nozzle length 1 mm, plunger pressure 20 kg / cm ² ).
The melt viscosity at 7 ° C. is in the range of 7 × 10 ⁴ to 30 × 10 ⁴ poise, the melt viscosity at 140 ° C. is 6 × 10 ⁴ poise or less, and
No plasticized polyvinyl butyral sheet having a melt viscosity at 0 ° C. of 2 × 10 ⁶ poise or more was used.

By increasing the amount of the plasticizer to be added to the polyvinyl butyral resin, the melt viscosity at 140 ° C. of the plasticized polyvinyl butyral sheet can be set to 6 × 10 ⁴ poise or less. However, in this case, the melt viscosity at 110 ° C. becomes 2 × 10 ⁶ poise or less, which causes inconvenience.

In the present invention, in order to lower the melt viscosity of the plasticized polyvinyl butyral sheet, a polyvinyl butyral resin having a molecular weight smaller than that of the conventional one is used. In order to produce such a polyvinyl butyral resin, polyvinyl alcohol having an average degree of polymerization of 1,000 to 2,000, preferably 1,300 to 1,700 is used as a raw material. When polyvinyl alcohol having an average degree of polymerization of less than 1000 is used, the impact strength of the interlayer film formed from the obtained polyvinyl butyral resin is reduced.

In order to obtain the desired average degree of polymerization of the polyvinyl alcohol raw material, two or more kinds of polyvinyl alcohols out of the range of the above average degree of polymerization are mixed, and as a result, the range falls within the range of the above average degree of polymerization. You may do so.
The saponification degree of polyvinyl alcohol may be 96 mol% or more.

In the present invention, the melt viscosity of the plasticized polyvinyl butyral sheet is also controlled by the degree of butyralization of the polyvinyl butyral resin. When the degree of butyralization is high, the melt viscosity is low, and when the degree of butyralization is low, the melt viscosity is high. In this case, the melt viscosity at 140 ° C and the melt viscosity at 110 ° C both show the same tendency,
The melt viscosity at 110 ° C has a greater effect.

The degree of butyralization of the polyvinyl butyral resin is from 60 to 70 mol%, preferably from 63 to 67 mol%. If the butyralization degree is less than 60 mol%, not only the desired melt viscosity cannot be obtained, but also the compatibility with the plasticizer becomes poor.
On the other hand, when the butyralization degree is higher than 70 mol%, butyraldehyde or a modified product thereof is apt to remain in the resin, which causes bubbles or the like to be generated in the laminated glass.

Further, the melt viscosity of the plasticized polyvinyl butyral sheet cannot be set in the above range only by adjusting the average polymerization degree of the raw material polyvinyl alcohol and the butyralization degree of the polyvinyl butyral resin as described above. Further, the temperature of the butyralization reaction in synthesizing the polyvinyl butyral resin must be adjusted to 50 to 100 ° C, preferably 70 to 90 ° C. When the butyralization reaction is carried out at a temperature of 50 to 90 ° C., the occurrence of gelation of the polyvinyl alcohol to be used is suppressed, and an increase in the melt viscosity of the obtained resin is prevented.

For the conventional interlayer film for laminated glass, polyvinyl butyral resin produced by a precipitation method using an aqueous medium is exclusively used. The reason is that the precipitation method using this aqueous medium is industrially advantageous because there is no need to recover an expensive solvent as compared with the solution method. However, in the precipitation method, since a large amount of catalyst (for example, 2 to 4% by weight of hydrochloric acid catalyst) is used, it is necessary to make the particles fine (for example, 50 μm or less) due to a problem in purification. In this case, in order to obtain uniform particles, the butyralization reaction is performed at a relatively low temperature (0 to 30).
C).

If the reaction is not carried out at a relatively low temperature, the scale adheres to the inner wall of the reactor, making it impossible to operate for a long time. The quality may be deteriorated, and from this point, the butyralization reaction must be performed at a relatively low temperature. However, when the butyralization reaction is performed at a relatively low temperature, gelation of polyvinyl alcohol is apt to occur, and the melt viscosity of the obtained resin increases.

In the present invention, for example, when both the loop reactor and the kettle reactor are used as shown in FIG. 1 and the particles of the reactant having a degree of butyralization of up to 40 mol% tend to agglomerate. The butyralization reaction can be performed at a relatively high temperature (50 to 100 ° C.) without aggregating the resin particles by performing the reaction such that the flow rate of the reaction solution is 5 m / sec or more in the loop reactor. I did it.

At this time, the inner surface of the loop reactor is made of a smooth glass lining material to prevent the adhesion of scale, and thus the industrial production of polyvinyl butyral resin by a relatively high temperature reaction. Enabled.

[0028]

According to the above-mentioned means, a high-grade flow tester (nozzle diameter 1 mm, nozzle length 1 mm, plunger pressure 20
(kg / cm ² ) The industrial production of an interlayer film for laminated glass comprising a plasticized polyvinyl butyral sheet having a melt viscosity at 140 ° C. of 6 × 10 ⁴ poise or less and a melt viscosity at 110 ° C. of 2 × 10 ⁶ poise or more. Production has become possible.

The interlayer film for a laminated glass in which the melt viscosity is set in a specific range as described above has a good heat fluidity and is suitable for the production of a laminated glass having a large curvature even when the laminated glass is manufactured. Air retention is prevented.

[0030]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples. Example 1 (1) Description of the reactor The reactor shown in FIG.
, Butyraldehyde tank 3 and first loop reactor
11, a second loop reactor 12, a second loop reactor 12
And a pot-shaped aging reactor 2.

The polyvinyl alcohol dissolving tank 1 and the first loop reactor 11 are connected by a supply pipe 24, the first loop reactor 11 and the second loop reactor 12 are connected by a transfer pipe 26, The two-loop reactor 12 and the kettle reactor 2 are connected by a transfer pipe 27. 27 is an extraction valve. The butyraldehyde tank 3 and the first loop reactor 11 are connected by a supply pipe 25.

A circulation pump 7, a pressure gauge 8, a flow meter 9 are provided in the first loop reactor 11 and the second loop reactor 12.
The supply pipes 24 and 25 are provided with supply pumps 14, respectively.

The polyvinyl alcohol dissolving tank 1 has a capacity of 10
The butyl aldehyde tank 3 is made of stainless steel having a capacity of 10 liters.
The first loop reactor 11 was formed by an inner glass lining pipe having a diameter of 40 mm, and the capacity was set to 1 liter.

The second loop reactor 12 is formed of an inner glass lining pipe having a diameter of 25 mm, and an auxiliary reactor 20 made of an inner glass lining having a capacity of 3.5 liters is provided in the pipe line, so that the total capacity is 5 liters. And The kettle reactor 2 is
Consists of a 100 liter inner glass lining material.

Each of the above glass linings has a surface roughness of 0.3 μm in Rz value. Here, the surface roughness is measured using a stylus-type roughness measuring instrument in accordance with ISO R468, and is the average roughness of 10 points measured. The kettle-shaped reactor 2 is provided with a reflux condenser (not shown) for preventing butyraldehyde from flowing out of the system.

(2) Production of Polyvinyl Butyral Resin Using the reaction apparatus shown in FIG. 1, a polyvinyl butyral resin was produced by the following method.

In the polyvinyl alcohol dissolving tank 1, pure water 64
Liters and 7.5 kg of polyvinyl alcohol having an average degree of polymerization of 1500 and a degree of saponification of 99.5 mol% were added and dispersed, and then the temperature was raised to 90 ° C. to dissolve the polyvinyl alcohol.
Cooled to ° C. Further, 560 g of hydrochloric acid having a concentration of 35% by weight was charged into the polyvinyl alcohol dissolving tank 1 as a catalyst for the butyralization reaction. Also, butyraldehyde tank 3
Butyl aldehyde was prepared.

Further, the first loop reactor 11 and the second loop reactor 12 were filled with pure water at 75 ° C. and circulated by operating the respective circulation pumps 7. First loop reactor 11
The flow rate in the reactor was adjusted to 6 m / sec, and the flow rate in the second loop reactor 12 was adjusted to 3 m / sec. Further, 10 liters of an aqueous solution of pure water and hydrochloric acid at 85 ° C. (hydrochloric acid concentration: 0.15% by weight) was charged into the kettle-shaped reactor 2 to enable stirring.

The aqueous solution of polyvinyl alcohol containing an acid catalyst and butyraldehyde were supplied to the first loop reactor 11 at a rate of 1 liter / minute of the aqueous solution and 57.5 g / minute of butyraldehyde. The two are mixed through the junction, and the mixture is circulated in the first loop reactor 11 by the circulation pump 7. At this time, the first loop reactor
The flow rate of the mixture circulating through 11 was adjusted to 6 m / sec, and the reaction proceeded while preventing coalescence of particles.

An amount of the slurry liquid corresponding to the supply of the aqueous solution of polyvinyl alcohol and butyraldehyde is transferred into the second loop reactor 12 and circulated through the second loop reactor 20 by the circulation pump 7. At this time, the second loop reactor 11
The flow rate of the slurry circulating was adjusted to 3 m / sec, and the extraction valve 17 was adjusted so that the pressure became 2 kg / cm ² , and the reaction proceeded while preventing coalescence of particles. In addition, when the slurry liquid was sampled from the outlet of the first loop reactor 11 and the butyralization degree of the resin was measured, the butyralization degree was 40.0 mol%.

Further, the slurry liquid circulating in the second loop reactor 11 is transferred into the kettle reactor 2, and the rotation speed of the stirring blade of the kettle reactor 2 is 250 rpm, and the peripheral speed of the stirring blade is 2 m / sec. The reaction was performed at 85 ° C. for 3 hours and aged while stirring at a usage efficiency of 10 w / liter, and then cooled to 40 ° C. The second
When the slurry liquid was sampled from the outlet of the loop reactor 11 and the butyralization degree of the resin was measured, the butyralization degree was 55 mol%. After that, neutralize in the usual way,
After washing with water and drying, a granular polyvinyl butyral resin was produced.

With respect to the obtained polyvinyl butyral resin, a vinyl butyral content and a vinyl alcohol content were measured based on JIS K-6728, and a butyral conversion degree was determined. As a result, the butyral conversion degree was 64.7 mol%.

[0043](3) Plasticized polyvinyl butyral sheet
(Interlayer) production A plasticizer is added to 100 parts by weight of the polyvinyl butyral resin.
And triethylene glycol di-2-ethyl butyrate 40
Add parts by weight, mix well with a mortar, put in a frame
Temperature 150 ℃, pressure 100kg / cm^TwoPress for 30 minutes under the conditions
And transparent plasticized polyvinyl butyral with a thickness of 0.76 mm
Manufactured.

The sheet was placed in a constant temperature / humidity room at a temperature of 25 ° C. and a humidity of 23% RH for 3 hours, and the sheet was placed in a constant-temperature flow tester (Shimadzu FT-500 type flow tester). Nozzle diameter 1mm, nozzle length 1mm, plunger pressure 20
The melt viscosity at 140 ° C. and 110 ° C. was measured under the conditions of kg / cm ² . The melt viscosity at 140 ° C. was 4.6 × 10 ⁴ poise, and the melt viscosity at 110 ° C. was 2.1 × 10 ⁶ poise.

(4) Production of Laminated Glass This plasticized polyvinyl butyral sheet was used as an intermediate film, and sandwiched between glass plates of 2.5 mm thick × 30 cm × 30 cm (in this case, the inner center of one side of the glass plate) The part with a diameter of 160 mm and the center of which was formed with an arc-shaped curvature so as to have a depth of 300 μm was used), placed in a rubber bag and degassed at a degree of vacuum of 600 mmHg and a temperature of 80 ° C. And perform preliminary bonding. After that, the temperature is set in the air type autoclave.
At 140 ° C, 13 kg / cm ² pressure for 20 minutes
A laminated glass was made.

The interlayer film of the laminated glass flowed uniformly over the entire surface, and no air remained at all. In addition, in order to evaluate the blocking properties of the membranes, the plasticized polyvinyl butyral sheet was cut into two 15 cm (length) × 15 cm (width) plates.
g in a constant temperature and humidity room with a temperature of 20 ° C and a humidity of 23% RH.
After 20 hours, this was measured with a tensile tester at a tensile speed of 500 mm / min at a peeling force of 90 degrees square (T type). The peeling force was 515 g / 15 cm. Did not.

Example 2 In Example 1, the average degree of polymerization was 1500 and the degree of saponification was 99.5 mol%.
7.5 kg of polyvinyl alcohol was changed to 7.5 kg of polyvinyl alcohol having an average degree of polymerization of 1700 and a saponification degree of 99.1 mol%. Other than that, it carried out similarly to Example 1.

In this case, the degree of butyralization of the polyvinyl butyral resin is 65.2 mol%, and the melt viscosity at 140 ° C. of the plasticized polyvinyl butyral sheet is 5.3 × 10 ⁴ poise, 110
The melt viscosity at ° C. was 2.3 × 10 ⁶ poise. Also, no air remained in the interlayer film of the laminated glass. Further, the peeling force was 505 g / 15 cm, and there was no problem in work.

Example 3 In Example 1, the concentration was used as a catalyst for the butyralization reaction.
560 g of 35% by weight hydrochloric acid was changed to 200 g. The reaction and aging time in the kettle reactor 2 were changed from 3 hours to 4 hours. Other than that, it carried out similarly to Example 1.

In this case, the degree of butyralization of the polyvinyl butyral resin is 67.1 mol%, and the melt viscosity at 140 ° C. of the plasticized polyvinyl butyral sheet is 3.8 × 10 ⁴ poise, 110
The melt viscosity at ° C. was 2.1 × 10 ⁶ poise. Also, no air remained in the interlayer film of the laminated glass. In addition, the peel force was 545 g / 15 cm, and there was no problem in work.

Example 4 In Example 1, the reaction in the kettle reactor 2 was carried out, and the ripening temperature was 85.
C and the time 3 hours were changed to 6 hours at 70 ° C. Other than that, it carried out similarly to Example 1.

In this case, the degree of butyralization of the polyvinyl butyral resin is 64.4 mol%, and the melt viscosity at 140 ° C. of the plasticized polyvinyl butyral sheet is 5.3 × 10 ⁴ poise, 110
The melt viscosity at ° C. was 2.2 × 10 ⁶ poise. Also, no air remained in the interlayer film of the laminated glass. In addition, the peeling force was 560 g / 15 cm, and no operational problem occurred.

Comparative Example 1 In Example 1, the average degree of polymerization was 1500 and the degree of saponification was 99.5 mol%.
7.5 kg of polyvinyl alcohol was changed to 7.5 kg of polyvinyl alcohol having an average degree of polymerization of 2400 and a saponification degree of 98.8 mol%. Other than that, it carried out similarly to Example 1.

In this case, the degree of butyralization of the polyvinyl butyral resin is 64.2 mol%, and the melt viscosity at 140 ° C. of the plasticized polyvinyl butyral sheet is 10 × 10 ⁴ poise, 110 ° C.
Has a melt viscosity of 2.5 × 10 ⁶ poise. Further, air remained in the interlayer film of the laminated glass. this is,
This is because the melt viscosity at 140 ° C. is too high. Further, the peeling force was 505 g / 15 cm, and there was no problem in work.

Comparative Example 2 In Example 1, the supply amount of butyraldehyde was 57.5 g /
Min was changed to 51.4 g / min. Other than that, it carried out similarly to Example 1.

In this case, the degree of butyralization of the polyvinyl butyral resin is 59.0 mol%, and the melt viscosity at 140 ° C. of the plasticized polyvinyl butyral sheet is 12 × 10 ⁴ poise, 110 ° C.
Has a melt viscosity of 2.5 × 10 ⁶ poise. Further, air remained in the interlayer film of the laminated glass. this is,
This is because the melt viscosity at 140 ° C. is too high. In addition, the peel force was 450 g / 15 cm, and there was no problem in work.

COMPARATIVE EXAMPLE 3 A kettle reactor was used as a reactor. In the kettle reactor, 64 liters of pure water, a polymerization degree of 1500, and a saponification degree of 99.5 mol% were used.
Was added and dispersed, and then heated to 90 ° C. to dissolve the polyvinyl alcohol while stirring, and then cooled to 30 ° C. Furthermore, in the kettle reactor, a concentration of 35% by weight as a catalyst for the butyralization reaction
After adding 510 g of hydrochloric acid, 1100 g of butyraldehyde was added.
Was added.

The solution was cooled, and when the temperature reached 10 ° C., 2860 g of butyraldehyde was added and the reaction was allowed to proceed with stirring to precipitate particles. Then, 5480 g of 35% by weight hydrochloric acid was added as an additional catalyst while adding 5080 g of hydrochloric acid. The temperature was raised to ° C. Further, the mixture was reacted and aged at 50 ° C. for 3 hours while stirring, and then cooled to 30 ° C. Thereafter, the resultant was neutralized, washed with water and dried in a conventional manner to produce a powdery polyvinyl butyral resin. The butyralization degree of the obtained polyvinyl butyral resin was 66.2 mol%. Except using this polyvinyl butyral resin, it carried out similarly to Example 1.

In this case, the melt viscosity at 140 ° C. of the plasticized polyvinyl butyral sheet was 20 × 10 ⁴ poise, and the melt viscosity at 110 ° C. was 3.0 × 10 ⁶ poise. Further, air remained in the interlayer film of the laminated glass. This is 140 ° C
Is too high. The peel force is 600
g / 15 cm, and no operational problems occurred.

Comparative Example 4 In Example 1, the supply amount of butyraldehyde was 57.5 g /
The minute was changed to a rate of 65 g / min. Otherwise, Example 1
The same was done.

In this case, the degree of butyralization of the polyvinyl butyral resin is 72.0 mol%, and the melt viscosity at 140 ° C. of the plasticized polyvinyl butyral sheet is 4.0 × 10 ⁴ poise, 110
The melt viscosity at ° C. was 1.1 × 10 ⁶ poise. Further, air remained in the interlayer film of the laminated glass. This is presumably because the edge of the membrane was sealed during suction and deaeration, resulting in insufficient deaeration. The peeling force is 1100g / 1
5 cm, there is blocking between membranes, and work is poor.

[0062]

As described above, the interlayer film for laminated glass of the present invention is prepared at 140 ° C. using a high-grade flow tester (nozzle diameter 1 mm, nozzle length 1 mm, plunger pressure 20 kg / cm ² ).
Of a plasticized polyvinyl butyral sheet having a melt viscosity of 6 × 10 ⁴ poise or less at 110 ° C. and a melt viscosity at 110 ° C. of 2 × 10 ⁶ poise or more. Good heat fluidity.

Therefore, even when a laminated glass having a large curvature is produced, air is prevented from remaining between the glass plate and the interlayer, and a laminated glass of good quality can be produced efficiently.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing one embodiment of an apparatus for producing a polyvinyl butyral resin used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polyvinyl alcohol dissolution tank 11 1st loop reactor 12 2nd loop reactor 14 Feed pump 2 Pot reactor 3 Butyraldehyde tank 7 Circulation pump 20 Auxiliary reactor

Claims (2)

(57) [Claims] 1. A high flow type flow tester (nozzle diameter 1 mm,
Nozzle length 1 mm, plunger pressure 20 kg / cm ² ) 14
An interlayer for laminated glass comprising a plasticized polyvinyl butyral sheet having a melt viscosity at 0 ° C. of 6 × 10 ⁴ poise or less and a melt viscosity at 110 ° C. of 2 × 10 ⁶ poise or more. 2. A laminated glass comprising the interlayer film for laminated glass according to claim 1 interposed.