JP2003040655A - Laminated glass and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a laminated glass without using an autoclave, enabling to perform laminating process only by depressing inside a hermetic sealed vessel or by vacuum degassing method and to achieve necessary characteristics for the laminated glass such as excellent transparency, adhesiveness, penetration resistance and weatherability, and to obtain the laminated glass produced by the method. SOLUTION: This method for producing the laminated glass comprises the steps of (A) forming a glass-thermoplastic laminate by sandwiching a thermoplastic sheet between a pair of glass sheets, (B) putting the laminate into an envelop and depressing or degassing inside atmosphere of the envelop, (C) heating the laminate at a prescribed temperature for a prescribed period of time, (D) leaking inside of the envelop while maintaining the heated temperature, and (E) cooling the laminate after maintaining at the prescribed temperature for the prescribed period of time.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a laminated glass and a method for manufacturing a laminated glass.

[0002]

Laminated glass obtained by sandwiching an interlayer film made of a thermoplastic resin sheet such as plasticized polyvinyl butyral resin between glass plates and adhering them together is widely used as a window glass for automobiles, aircrafts, buildings and the like. ing.

In this type of laminated glass, an interlayer film for laminated glass is usually sandwiched between a pair of glass plates, and this is passed through a nip roll (pressing roll) for handling (handling degassing method).
Alternatively, it is put in a rubber bag and suctioned under reduced pressure, pre-compressed while deaerating the air remaining between the glass plate and the interlayer film for laminated glass, and then heated and pressurized in an autoclave to perform main compression bonding. To be done. As described above, the laminated glass manufacturing process is complicated because it is divided into several steps.

The interlayer film for laminated glass is required to exhibit various properties required for a laminated glass, such as excellent transparency, adhesiveness, penetration resistance and weather resistance. Among them, a polyvinyl butyral resin having an excellent balance of these various properties is particularly preferably used.

However, the sheet made of polyvinyl butyral resin has a problem in that it is necessary to carry out the main pressure bonding during the production of laminated glass in an autoclave, and a large amount of capital investment is required to install the autoclave.

Therefore, in recent years, without using an autoclave,
Methods for producing good laminated glass have been investigated.
For example, Japanese Unexamined Patent Publication No. 8-104551 discloses a method of eliminating the use of an autoclave by finely setting the vacuum level and temperature during vacuum pressing. However, there has been a problem that the pre-bonding process is complicated and bake foaming occurs when the bonding process is performed under the humidity control conditions normally managed by the bonding process manufacturer. In addition, there is a problem that optical distortion occurs in the laminated glass due to residual distortion around the glass generated in the preliminary pressure bonding step. Furthermore, since the pressing pressure at the flow temperature of the resin film is not sufficient, the voids remaining in the laminate cannot be sufficiently diffused in the film, and bubbles remain. In addition, since the vacuum level is lowered at the same time as the temperature is raised, the degree of decompression inside the remaining bubbles is small, and even if the resin film leaks in a flowing state, the contraction rate of the bubbles is small and the bubbles do not disappear and remain. There was a problem.

[0007]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to perform a laminating process without the need for an autoclave during the production of laminated glass, and to provide excellent transparency. It is an object of the present invention to provide a production method capable of exhibiting various properties required for a laminated glass such as adhesiveness, penetration resistance, and weather resistance, and a laminated glass produced by the method for producing a laminated glass.

[0008]

The present invention according to claim 1 is a method for producing a laminated glass, wherein step A) a thermoplastic sheet is sandwiched between at least a pair of glasses to form a glass-thermoplastic sheet laminate. Then, step B) the laminate is put into an envelope, the atmosphere of the envelope is depressurized or deaerated, step C) the laminate is heated at a constant temperature for a certain period, and step D) the inside of the envelope is heated. Provided is a method for producing a laminated glass, which comprises: leaking while maintaining the temperature; and step E) maintaining the laminated body at a constant temperature for a certain time and then cooling the laminated body. Further, according to the invention of claim 2, the water content of the thermoplastic sheet when used in the step A) is 0.
The method for producing a laminated glass according to claim 1, wherein the content is 3% by weight or less. In the invention according to claim 3, the pressure reduction degree of the atmosphere in step B) is 8.0 to 61.3 kP.
A method for manufacturing a laminated glass according to claim 1 or 2, which is a. The present invention according to claim 4 provides the step C).
Heating temperature is 80 to 140 ° C, and heating time is 5 to 6
The method for producing a laminated glass according to any one of claims 1 to 3, wherein the method is 0 minutes. Further, the invention according to claim 5 has a holding temperature in step E) of 60 to 140 ° C. and a holding time of 30 seconds to 30 minutes.
A method for producing a laminated glass as described in the above item. Also,
The present invention according to claim 6 provides a laminated glass manufactured by the method for manufacturing a laminated glass according to any one of claims 1 to 5.

The present invention will be described in detail below. In step A) of the present invention, the thermoplastic sheet is sandwiched between at least a pair of glasses to form a glass-resin laminate.

The thermoplastic resin sheet in the present invention is not particularly limited as long as it can exhibit various properties required as a laminated glass such as excellent transparency, adhesiveness, penetration resistance and weather resistance. For example, those conventionally used such as 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 resin sheet can be mentioned. . Among these thermoplastic resin sheets, a plasticized polyvinyl acetal resin sheet typified by a plasticized polyvinyl butyral resin sheet is particularly preferably used because it has an excellent balance of these performances. Examples of the plasticized polyvinyl butyral resin include polyvinyl butyral resin (polyvinyl alcohol (hydroxyl group) 10 to
Those containing 40% by weight, 0 to 2.5% by weight of polyvinyl acetate (acetic acid group) and the rest having polyvinyl butyral) and a plasticizer (20 to 50 parts by weight per 100 parts by weight of plastic) are preferably used. . The thermoplastic sheet can be obtained by forming a plasticized polyvinyl acetal resin composition containing a plasticizer by a conventional method.

Examples of the plasticizer added to the polyvinyl acetal resin include triethylene glycol-di-2-ethylbutyrate (3GH) and triethylene glycol-di-2-ethylhexanoate (3G).
O), triethylene glycol-di-n-heptanoate (3G7) and the like.

The water content of the above-mentioned thermoplastic sheet is preferably 0.3% by weight or less, more preferably 0.2 to 0.3% by weight at the time of combining processing, that is, at the time of use.
Is the range. The water content may be 0.3% by weight or less immediately after the production of the thermoplastic sheet, or even if the water content immediately after the production is more than 0.3% by weight, it may be used under suitable conditions before use. The moisture content at the time of use may be adjusted to 0.3% by weight or less by controlling the humidity in the above or drying under reduced pressure. If the water content is more than 0.3% by weight, water contained in the thermoplastic sheet may evaporate and a foaming phenomenon may occur in the film during heating for pressure-bonding the laminated glass.

The method of controlling the humidity is not particularly limited, but a thermoplastic sheet may be used, for example, at a temperature of 20 to 25.
C. and humidity 25 to 30% RH, the humidity is controlled by leaving it to stand for a required time (generally 2 hours or more) for a necessary period of time (generally 2 hours or more).
The water content may be 0% by weight or less, or after the above-mentioned humidity control, it is dried under reduced pressure at a temperature of 20 to 25 ° C. for a necessary time (generally 1 hour or more) using, for example, a vacuum dryer. ．
It may be 3% by weight or less.

The water content referred to here is a value measured by the following method. [Measurement Method of Water Content] FIG. 1 shows that λ = 1 of the thermoplastic sheet.
The absorbance curve at 500 to 2000 nm is shown. Figure 1
Where A represents the maximum peak of water (λ = 1925 nm),
B represents the maximum peak of the methylene group (λ = 1705 nm). Using a near-infrared spectrophotometer, the absorbance curve of the thermoplastic sheet as shown in FIG. 1 was obtained, A / B was calculated, and the water content Y (% by weight) was obtained from the approximate expression in Table 1 below. .

[0015]

[Table 1]

The thickness of the thermoplastic resin sheet may be set in consideration of the penetration resistance and the like required for laminated glass and is not particularly limited, but it is used for a conventional interlayer film. Similarly, it is preferably about 0.2 to 2 mm.

Further, it is preferable that the thermoplastic sheet has a large number of embosses formed of fine irregularities on both sides thereof. The shape and method of forming the emboss are not particularly limited as long as the air can be completely degassed from the layers of the laminate, and can be used. By forming a large number of embosses consisting of fine irregularities on both sides of the thermoplastic sheet, in the pressure bonding step during the production of laminated glass, the air existing near the central portion of the laminated glass is sufficiently degassed,
The obtained laminated glass has a high quality without defective products due to the generation of bubbles.

The glass in the present invention is not particularly limited, and examples thereof include an inorganic glass plate, a polycarbonate plate,
An organic glass plate such as a polymethylmethacrylate plate may be used, or an inorganic glass plate and an organic glass plate may be used in combination. Further, the structure of the laminated glass is not limited to the usual three-layer structure composed of glass plate / thermoplastic sheet / glass plate, but may be composed of, for example, glass plate / thermoplastic sheet / glass plate / thermoplastic sheet / glass plate. It may have a multilayer structure.

In step B) of the present invention, the atmosphere in the envelope containing the glass-thermoplastic sheet laminate is depressurized or deaerated. By this step, the air existing between the envelope and the layer of the laminate can be eliminated, and at the same time, since the envelope shrinks, it is possible to provide a pressing effect of bringing the glass and the thermoplastic sheet into close contact with each other.

The envelope used for performing the above-mentioned depressurization is not particularly limited as long as it is a container / packaging capable of deaerating the air of the laminate and making it adhere tightly, for example, a vacuum bag such as a rubber bag is preferably used. To be Further, when the press effect of bringing the laminates into close contact with each other only by depressurizing or vacuum degassing is small, a pressing step may be further added after the step B). In that case, for example, pressing may be further performed on the depressurized rubber bag, or a pressing machine capable of depressurizing the atmosphere may be used.

The degree of pressure reduction by the above pressure reduction or vacuum deaeration is preferably 8.0 to 61.3 kPa, more preferably 21.3 to 34.7 kPa. Decompression degree is 6
If it is larger than 1.3 kPa, deaeration and adhesion of the laminate are not sufficient, and if it is smaller than 8.0 kPa, strain is generated in the laminate, and uniform pressing cannot be performed, so bubbles remain. The degree of pressure reduction described above indicates the actual pressure in the envelope.

In step C) of the present invention, the laminate is heated at a constant temperature for a constant time. The heating temperature is preferably 80 to 140 ° C., and the heating time is preferably 5 to 60 minutes. Heating temperature or heating time is 80
If the temperature is less than or equal to 5 minutes, the thermoplastic sheet may not be sufficiently softened and may not sufficiently adhere to the glass, so that safety as a laminated glass may not be ensured. On the other hand, if the temperature is higher than 140 ° C. or longer than 60 minutes, volatile components such as a plasticizer may cause foaming and impair the appearance of the glass. still,
The starting point of the heating is not particularly limited, and the temperature may be raised even after the depressurization is finished or while the depressurization is performed.

In step D) of the present invention, the inside of the envelope is leaked and returned to atmospheric pressure (normal pressure) while maintaining the heating temperature. When the atmosphere of the laminated body is returned to the atmospheric pressure, the atmospheric pressure works in the direction of contracting and extinguishing the air bubbles in the reduced pressure state remaining inside the laminated body. Therefore, by maintaining the thermoplastic sheet resin in the laminate at a temperature at which it can flow, the resin flows into the bubbles following the contraction of the bubbles, and the bubbles disappear.

In step E) of the present invention, the laminate is held at a constant temperature for a predetermined time and then cooled. The holding time is preferably 60 to 140 ° C., and the holding time is preferably 30 seconds to 30 minutes. When the holding temperature and the holding time are within the above ranges, the voids remaining in the laminated body in a reduced pressure state can be sufficiently shrunk, and the foaming of volatile components such as a plasticizer does not occur. Further, since the heating and pressure bonding in the step C is performed at a temperature at which the thermoplastic sheet sufficiently flows, the periphery of the laminated glass is
Since the flow strain is larger than that in the central portion, the optical strain is large. Therefore, in this step E, the optical distortion is removed by annealing the laminated body.

The above-mentioned method for producing a laminated glass of the present invention is different from the conventional method for producing a laminated glass by a conventional laminating process, and it is possible to perform a laminating process without using an autoclave. is there. That is,
In the case of a method for producing a laminated glass by a usual laminating process, a thermoplastic sheet is sandwiched between at least a pair of glasses, and first depressurized or vacuum deaeration method or handling deaeration method is performed to pre-press and degas and temporarily bond. After that, the step of putting this temporary bonded body in an autoclave and performing main bonding to perform main bonding to form a laminated glass is used. In the case of the method for producing a laminated glass of the present invention, the present invention is provided between at least a pair of glasses. It is possible to adopt a process of sandwiching the thermoplastic sheet and temporarily and permanently adhering continuously and continuously to form a laminated glass.

(Function) In the present invention, a method has been found in which, after heating the laminate, leakage occurs while maintaining the temperature, and leakage occurs after maintaining for a certain period of time. That is, when the atmosphere of the laminate is returned to the atmospheric pressure, if the thermoplastic resin retains fluidity, the depressurized bubbles inside the laminate are subjected to the atmospheric pressure in the direction in which they shrink. Then, since the thermoplastic resin in a fluid state can flow into the depressurized bubbles, the bubbles shrink and disappear, and a laminated glass having a good appearance can be obtained.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The following examples are given to illustrate the present invention in more detail, but the present invention is not limited to these examples.

(Example 1) 100 parts by weight of polyvinyl butyral resin (average degree of polymerization 1700, residual acetyl group 1 mol%, butyralization degree 69 mol%) was added to triethylene glycol-di-2-ethylhexa as a plasticizer. 41 parts by weight of Noate (3GO) was added and mixed, melt-kneaded and extruded into a sheet to obtain a polyvinyl butyral resin sheet (PVB sheet) having a thickness of 0.76 mm. next,
Using a pair of embossing rolls, a large number of embosses having fine chevron-shaped irregularities were applied to both sides of this PVB sheet to manufacture a thermoplastic sheet having embossed patterns formed on both sides. The obtained thermoplastic sheet is heated to a temperature of 20 to 25
When the water content was measured by the above-mentioned measuring method after being left for 2 hours in an atmosphere having a temperature of 25 ° C and a humidity of 25% to 30% RH to control the humidity, the water content was 0.29% by weight.

Next, the thermoplastic sheet obtained above is sandwiched between two transparent inorganic glass plates, the laminated glass component (laminate) is placed in a rubber bag (vacuum bag), and the degree of vacuum is -60 kPa (absolute). The pressure was 41 kPa) and the temperature was 130 ° C. for 20 minutes, the inside of the rubber bag was returned to atmospheric pressure (leakage), and the temperature was maintained at 130 ° C. for 5 minutes and then cooled. Ten laminated glasses were produced by the above method, and no bubbles remained in any of the laminated glasses, and they had a good appearance.

(Comparative Example 1) The same thermoplastic sheet used in Example 1 was sandwiched between two transparent inorganic glass plates, and this laminated glass component (laminate) was placed in a rubber bag (vacuum bag) and depressurized. -60 kPa (absolute pressure 41 kP
a), the temperature was kept at 130 ° C. for 20 minutes, and after cooling, the inside of the rubber bag was returned to atmospheric pressure (leak). With the above method,
Ten laminated glasses were prepared, but bubbles remained in eight of the ten laminated glasses, and a transparent laminated glass could not be obtained.

(Comparative Example 2) The same thermoplastic sheet used in Example 1 was sandwiched between two transparent inorganic glass plates, the laminated glass component (laminate) was placed in a rubber bag (vacuum bag), and the pressure was reduced. -60 kPa (absolute pressure 41 kP
a), the temperature was gradually heated to 130 ° C. at a temperature rising rate of 10 ° C./min, and returned to normal pressure within 30 minutes from the start of heating. Thirteen
When the temperature reached 0 ° C., heating was stopped, and at the same time, the pressure inside the rubber bag was completely returned to atmospheric pressure. Ten laminated glasses were produced by the above-mentioned method, but bubbles out of the embossed voids remained in four of the ten laminated glasses, and a transparent laminated glass could not be obtained.

[0032]

EFFECTS OF THE INVENTION The laminated glass of the present invention and the method for producing the same perform steps A) to E) described above, so that it is possible to perform a laminating process that does not require an autoclave.
Therefore, a large amount of capital investment is not required, and the productivity is excellent because it is a simple one-step manufacturing method. Further, in the above step, no bubbles remain in the laminated glass, excellent transparency without quality defects due to occurrence of foaming phenomenon, providing a laminated glass without optical distortion, and adhesiveness, penetration resistance,
Combines various properties required for laminated glass such as weather resistance.

[0033]

[Brief description of drawings]

FIG. 1 is a thermoplastic sheet having λ of 1500 to 2000 nm.
2 is an absorbance curve in FIG.

[Explanation of symbols]

Maximum peak of water (λ = 1925 nm) Maximum peak of B methylene group (λ = 1705 nm)

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29L 9:00 B29L 9:00 F term (reference) 4F211 AA10 AA19 AA23 AA42 AD04 AD08 AG02 AG03 AH17 AH30 AH31 AH46 AM28 AR06 AR11 TA01 TC02 TD11 TH02 TH06 TQ07 TQ09 TQ10 TW15 4G061 AA02 AA03 AA04 BA01 BA02 CA02 CB03 CB19 CD02 CD18 DA23 DA30 DA46 DA61 DA67

Claims (6)

[Claims] 1. A method for producing a laminated glass, comprising the step of A) sandwiching a thermoplastic sheet between a pair of glasses to form a glass-thermoplastic sheet laminate, and the step B) placing the laminate in an envelope, The atmosphere of the envelope is decompressed or degassed, step C) heating the laminate at a constant temperature for a certain time, step D) leaking while maintaining the heated temperature in the envelope, and step E) removing the laminate. A method for producing a laminated glass, which comprises holding the material at a constant temperature for a certain time and then cooling it. 2. The method for producing a laminated glass according to claim 1, wherein the water content of the thermoplastic sheet when used in step A) is 0.3% by weight or less. 3. The degree of pressure reduction of the atmosphere in step B) is
It is 8.0-61.3 kPa, The manufacturing method of the laminated glass of Claim 1 or 2 characterized by the above-mentioned. 4. The heating temperature in step C) is 80 to 14
The method for producing a laminated glass according to any one of claims 1 to 3, wherein the temperature is 0 ° C and the heating time is 5 to 60 minutes. 5. The holding temperature in step E) is 60-14.
The method for producing a laminated glass according to any one of claims 1 to 4, wherein the temperature is 0 ° C and the holding time is 30 seconds to 30 minutes. 6. A laminated glass produced by the method for producing a laminated glass according to any one of claims 1 to 5.