JP3137504B2 - Method for recovering interlayer film from laminated glass - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering an interlayer film from a laminated glass. More particularly, the present invention relates to a method of separating a laminated glass used for a vehicle or a building flat plate and the like from an interlayer so that the interlayer can be reused.

[0002]

2. Description of the Related Art Laminated glass used for safety glass, such as window glass of buildings and windshields of automobiles,
It is formed by disposing an interlayer film for laminated glass between two glass plates. As the intermediate film, a film made of a thermoplastic resin such as a polyvinyl butyral resin is generally used.

[0003] Laminated glass that is no longer needed due to defects in dimensions, appearance, etc., cannot be easily separated from the glass plate and interlayer film after being recovered from the market. Can be In addition, the interlayer film on which the glass pieces are adhered after pulverizing the laminated glass is disposed of by incineration or the like.

[0004]

However, if the unneeded laminated glass is buried in the ground as described above, the problem of environmental destruction is caused. In addition, when the interlayer film with the glass fragments attached is incinerated, unmelted glass becomes glass dust and pollutes the atmosphere.On the other hand, the molten glass accumulates on the combustion stoker and hinders the operation of the combustion device. And other problems.

Therefore, various methods for recovering glass from laminated glass have been proposed (Japanese Patent Laid-Open No. 49-31722).
And JP-A-57-209847) only recover the glass, but do not consider the recovery of the interlayer film.

Accordingly, the present invention is intended to solve the above-mentioned drawbacks, and an object of the present invention is to recycle an intermediate film by separating the glass and the intermediate film without discarding the laminated glass that is no longer needed. It is to provide a method that can be.

[0007]

The method for recovering glass from a laminated glass according to the present invention is characterized in that a laminated glass formed by disposing an intermediate film made of a thermoplastic resin between a pair of glass plates is pulverized at a low temperature and a glass powder is formed. , An intermediate film powder, and a step of obtaining an intermediate film piece having glass particles attached thereto (hereinafter, these three types of powder pieces are collectively referred to as “finely pulverized product”). Immersed in a liquid of 2 to 1.5, applying a shearing force to the finely pulverized product so that the speed difference with the liquid is 1.8 m / sec or more, The method includes a step of separating using a specific gravity difference, whereby the above object can be achieved.

[0008] The low-temperature pulverization is preferably performed at -60 ° C to -100 ° C. The step of applying a shearing force to the finely pulverized product is, for example, a process of rotating a liquid in which the finely pulverized product is immersed, or applying a liquid flow.

Next, the present invention will be described in detail. As shown in FIG. 1, the laminated glass 10 includes two glass plates 1, 1.
The intermediate film 2 is formed between the two. The glass plate 1 is usually a transparent, translucent, opaque or colored plate glass.

The two glass plates 1, 1 may be of the same type or of different types. Also,
The thickness and size of the glass plate 1 are not limited, and may be generally commercially available. Specifically, the thickness is 1 to 20 m.
m. The resin forming the intermediate film 2 is usually a thermoplastic resin, and includes conventionally known resins used for this kind of laminated glass, such as polyvinyl butyral, polyurethane, and ethylene-vinyl acetate copolymer. Particularly preferred are plasticized polyvinyl butyral and polyurethane. The intermediate film 2 may contain a plasticizer, an ultraviolet absorber, an antioxidant, and the like.

In the present invention, when the interlayer film is recovered from the laminated glass 10 having the above structure, which is no longer required in the market, the laminated glass 10 is first cooled at a temperature of -60 ° C to -100 ° C for 2 hours. Crush the laminated glass 10 cooled at low temperature,
As shown in FIG. 2, glass powder 1a, interlayer powder 1b,
And a finely pulverized product 2 comprising an intermediate film 1c to which glass fragments 1d are attached.

As a method of pulverizing the laminated glass 10 cooled at a low temperature, a mechanical pulverization method using a press roll and a hammering device can be adopted. The step of obtaining the finely pulverized product 2 from the low-temperature cooled laminated glass 10 can be adjusted by pulverization conditions, for example, pressure of a press roll, roll clearance, hammering speed, and the like.

The laminated glass 1 thus cooled at a low temperature.
By pulverizing 0, a finely pulverized product 2 can be obtained. That is, the glass plate 1 is mechanically pulverized into glass by mechanical pulverization, the intermediate film 2 is softened by low-temperature cooling (-60 ° C. or less) due to the characteristics of the synthetic resin, and is mechanically pulverized. 2 breaks into a vitreous fracture.

Since there are various types of laminated glass depending on the color of the glass plate 1 and the intermediate film 2 and the like, before the low-temperature pulverization of the laminated glass 10, the glass plate 1 and the intermediate film 2 are colored. It is preferable to separate them separately.

Next, the finely pulverized product 2 is immersed in a liquid (water or hot water) adjusted to a specific gravity of 1.2 to 1.5. here,
A method for preparing a liquid adjusted to a specific gravity of 1.2 to 1.5 is such that an organic acid salt is added to water or warm water so as to be 20 wt% to 80 wt%, and an aqueous solution having a specific gravity of 1.2 to 1.5 is obtained. Can be made. Examples of the organic acid salt include calcium acetate, barium acetate, potassium acetate, and sodium acetate.

By immersing the finely pulverized product 2 in the liquid adjusted to a specific gravity of 1.2 to 1.5 in this way, the intermediate film powder 1b (specific gravity of about 1.08 )
Can be levitated by the difference in specific gravity. On the other hand, the intermediate film piece 1c (specific gravity of about 2.5) to which the glass powder 1a (specific gravity of about 2.5) and the glass fine particles 1d adhere are settled due to the specific gravity difference.

Here, the surface of the intermediate film piece 1c to which the glass particles 1d are attached swells because it is in a liquid, and the intermediate film piece 1c swells.
The adhesive strength of c decreases. In this case, the adhesive strength can be further reduced by adding aqueous silicon or the like. In addition,
The water temperature is preferably 5 ° C to 40 ° C, and the immersion time is preferably a time during which the intermediate film piece 1c swells sufficiently.

Next, simultaneously with, or after a predetermined time from, dipping the intermediate film piece 1c to which the glass fine particles 1d adhere to the liquid adjusted to a specific gravity of 1.2 to 1.5, the glass fine particle 1d
A shear force is applied to the intermediate film piece 1c to which is adhered. This step is for completely removing the glass particles 1d from the intermediate film 1c by applying a physical force to the intermediate film piece 1c.

The shear force applied to the intermediate film piece 1c is such that the speed difference between the intermediate film piece 1c and the liquid is 1.8 m / sec or more, and is 2.0 m / sec or more. Is preferred. When the speed difference between the intermediate film piece 1c and the liquid is less than 1.8 m / sec, since the force acting on the glass fine piece 1d from the liquid is small, the glass fine piece 1d is completely removed from the intermediate film piece 1c. It cannot be removed.

As a method for applying a shearing force to the intermediate film piece 1c to which the glass fine particles 1d are attached, for example,
Rotating the liquid immersed in the intermediate film piece 1c
There is a method of applying a liquid flow to the surface. In addition, glass flakes 1d
As a method of rotating the liquid immersed in the intermediate film piece 1c to which the glass particles 1d are attached, for example, a stirrer 3 having a stirring rod 5 as shown in FIG.
There is a method in which c is rotated while being applied to the stirring rod 5.

In the case of the stirrer 3 shown in FIG. 2, the stirring rods 5 extend horizontally on both sides from the rotary shaft 4 and are provided at the upper, middle and lower stages, respectively. Projections 6 projecting upward at one end of each stirring rod 5 and downward at the other.
Are provided respectively.

The number, thickness, length, shape, and fixing direction and position of the stirring rod 5 with respect to the rotating rod 4 are not particularly limited. Further, the formation position of the protrusion 6 is not limited to the tip of the stirring rod 5,
Further, a plurality of projections 6 may be provided on one stirring rod 5. Further, the direction may be either the upper or lower direction, and the size is not particularly limited. Note that the projection 6 may not be provided depending on the shape of the stirring rod 5.

The direction of rotation of the stirring rod 5 is not limited, and may be rotated in one direction and then in another direction. Furthermore, the rotation speed of the rotating shaft 4 is such that the speed difference between the intermediate film piece 1c and the liquid is 2.0 m / sec or more, and differs depending on the size and thickness of the intermediate film piece 1c. .

Further, the number of rotations of the rotating shaft 4 is appropriately set according to the length of the stirring rod 5. For example, in the case of the stirring rod 5 in FIG. 2, the rotation speed of the rotating shaft 4 is 800 rpm or more, and particularly preferably 1000 rpm or more.

In the present invention, the time for applying the shearing force to the intermediate film piece 1c is determined by the time when the glass fine piece 1d is applied to the intermediate film piece 1c.
It is time to be more removed.

[0026]

[Function] A finely pulverized product obtained by crushing unnecessary laminated glass at a low temperature (intermediate film specific gravity: about 1.08, glass specific gravity: about 2.
5) is immersed in a liquid adjusted to a specific gravity of 1.2 to 1.5,
The interlayer powder is levitated using the specific gravity difference. Furthermore, by reducing the adhesive force to the interlayer piece to which the glass piece has adhered and simultaneously applying a physical shearing force to the glass piece, the glass piece can be removed from the interlayer piece.

Glass particles removed (specific gravity: about 2.5)
Settles due to the difference in specific gravity from the liquid, and the intermediate film piece (specific gravity: about 1.08) floats. That is, specific gravity 1.2 to 1.5
In the liquid adjusted to the above, the heavier glass sediments, and the light interlayer floats. By utilizing the difference in specific gravity in this way, the glass and the intermediate film are separated, and the collection becomes easy.

[0028]

Next, an embodiment of the present invention will be described with reference to FIGS.

[Example 1] An intermediate film 2 made of polyvinyl butyral having a thickness of 0.76 mm was sandwiched between two float glass sheets 1 and 1 having a thickness of 2.5 mm.
A transparent laminated glass 10 of 00 mm was produced. The laminated glass 10 was cooled at a low temperature (temperature: -100 ° C., cooled for 2 hours), and then attached to an automatic hammering device. In this automatic hammering device, the bottom surface is formed into a curved surface with a radius of curvature of 50 mm, the effective hitting diameter is 5 mm, and the weight is 2 mm.
It has a hammer head of 40 g, and the striking force of the hammer head can be adjusted by a spring screw.

Next, the entire surface of the laminated glass 10 is uniformly hit with a hammer head to crush the laminated glass 10,
An intermediate film piece 1c (collectively, "finely pulverized product 2") to which the glass powder 1a, the intermediate film powder 1b, and the glass fine piece 1d were attached was produced.

Next, potassium acetate was added to water at a water temperature of 20 ° C. to prepare a 50 wt% aqueous solution, that is, an aqueous solution adjusted to a specific gravity of 1.2.
g.

Next, a stirrer 3 as shown in FIG. 2 (the length of the stirring rod 5 a = 500 mm, c = 100 mm, d = 200 mm)
mm, the height b of the projections = 20 mm, and the diameter (thickness) t of the stirring rod 5 = 10 mm). Then, all the stirring rods 5 are rotated in the same direction at a rotation speed of 800 rpm for 60 minutes, and the speed difference between the intermediate film piece 1c to which the intermediate film powder 1b and the glass fine particles 1d adhere and the water is 2.0 m / sec.
By applying a shearing force such that the glass particles 1d are removed, the glass particles 1d (specific gravity of about 2.5) are removed from the interlayer film pieces 1c (specific gravity of about 2.5) to which the glass particles 1d are attached, and the glass particles 1d are removed.
The intermediate film piece 1c (specific gravity of about 1.08) from which was removed was floated using the specific gravity difference.

In this way, the intermediate film piece 1c from which the glass particles 1d have been removed and floated, and the intermediate film powder 1b which has floated when immersed in an aqueous solution which has already been adjusted to a specific gravity of 1.2 are collected and heated. And the intermediate film was reshaped. The intermediate film was sandwiched between two float glass sheets having a thickness of 2.5 mm, and heated and pressed to produce a laminated glass.

Example 2 A laminated glass was produced in the same manner as in Example 1 except that the time for applying a shearing force at which the speed difference with water was 2.0 m / sec was 300 minutes. Was prepared.

Comparative Example 1 In Example 1, the specific gravity was 1.
The finely pulverized product 2 was immersed in normal water (20 ° C., specific gravity 1.0) without using the aqueous solution adjusted to 2, and the speed difference with water was 2.0 m / sec. A laminated glass was produced in the same manner as in Example 1 except that the time for applying the shearing force was set to 300 minutes.

The recovery rate of the interlayer obtained in Examples 1 and 2 and Comparative Example 1, the ease of recovery in the step of separating the interlayer and glass from each other, and the optical properties of the laminated glass were measured in accordance with JIS3212. . Table 1 shows the results.

[0037]

[Table 1]

From Table 1, it can be seen that the recovery rate of the intermediate films obtained in Examples 1 and 2 and Comparative Example 1 increases as the time for applying the shearing force increases.

In the step of separating the intermediate film and the glass, the intermediate film floats by using the specific gravity difference between the intermediate film and the glass in the first and second embodiments, that is, the aqueous solution adjusted to a specific gravity of 1.2. It can be seen that it is easy to collect.

Further, it can be seen that the laminated glasses obtained in Examples 1 and 2 and Comparative Example 1 have high light transmittance.

Although the above embodiment has been described centering on the recovery of the intermediate film, the present invention is not limited to recovering only the intermediate film. Needless to say, it can be reused.

[0042]

As is apparent from the above description, according to the present invention, the glass can be completely removed from the unnecessary interlayer film of the laminated glass, so that the intermediate film can be easily recovered. The intermediate film can be reused. These intermediate films can also be used for new applications such as transparent light-scattering glass. Further, a plasticizer can be separated from the intermediate film, and the intermediate film can be used as an adhesive or an emulsified emulsion and used as a soil agent.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing an example of a section of a laminated glass.

FIG. 2 is a view showing a finely pulverized product obtained by cooling and pulverizing a laminated glass.

FIG. 3 is an explanatory view schematically showing the configuration of a stirrer 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass plate 1a Glass powder 1b Intermediate film powder 1c Intermediate film piece to which glass flakes adhered 1d Glass flakes 2 Intermediate film 3 Stirrer 4 Rotating shaft 5 Stirrer bar 6 Projection 10 Laminated glass

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI B09B 5/00 R (56) References JP-A-5-309655 (JP, A) JP-A-6-219793 (JP, A) JP-A-4-349152 (JP, A) JP-A-5-213634 (JP, A) JP-A-6-247752 (JP, A) JP-A-6-247751 (JP, A) JP-A-56-149340 JP-A-57-209847 (JP, A) JP-A-6-316446 (JP, A) JP-A-6-345499 (JP, A) JP-A-49-31722 (JP, A) Kaihei 6-91193 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B09B 5/00 B29B 17/00-17/02 C03C 27/00-29/00 B02C 19/00 -19/22

Claims (1)

(57) [Claims] A laminated glass formed by disposing an intermediate film made of a thermoplastic resin between a pair of glass plates is pulverized at a low temperature, and a glass powder, an intermediate film powder, and an intermediate film piece having glass particles attached thereto ( Hereinafter, these three types of powder pieces are collectively referred to as “finely pulverized product”), and the finely pulverized product is immersed in a liquid having a specific gravity of 1.2 to 1.5, and a speed difference from the liquid is obtained. While applying a shearing force to the finely pulverized product such that the intermediate film powder is 1.8 m / sec or more to float the intermediate film powder in the finely pulverized product and the intermediate film piece from which glass particles have been removed, A method of separating the interlayer and the glass from the laminated glass by a specific gravity difference, the method including recovering the interlayer from the laminated glass.