JP7087669B2 - Adhesive for glass laminate, fluororesin sheet for glass laminate and glass laminate - Google Patents

Description

The present invention relates to an adhesive for a glass laminate, a fluororesin sheet for a glass laminate containing the adhesive, and a glass laminate obtained by using these.

The glass plate is a material having transparency and strength, but has weak impact resistance, and as a method for compensating for it, safety glass bonded to a plastic sheet is generally used. However, a general plastic sheet can prevent the scattering of debris when the glass breaks, but the plastic sheet burns in the event of a fire, so that the flame retardancy cannot be satisfied. Therefore, a fireproof safety glass in which a fluororesin sheet is adhered to a glass plate has been proposed as a glass having fireproof / flameproof properties and also having a debris scattering prevention property even if it breaks in normal times.

However, since the fluororesin sheet has poor adhesiveness to other materials such as glass, it is necessary to use an adhesive in order to achieve strong adhesion. Even if materials such as polyvinyl butyral and ethylene-vinyl acetate copolymer used as the above were applied to the adhesion between the fluororesin sheet and the glass, it was not possible to achieve good transparency and strong adhesion. ..

Proposals have been made to solve this problem and achieve strong adhesion without compromising the high degree of transparency of glass. For example, Patent Document 1 proposes an adhesive containing a fluororesin component of 40 to 80% by weight and an acrylic resin component of 60 to 20% by weight. Regarding the adhesive strength, the normal strength and the post-boil strength are evaluated. Although the strength after boiling was lower than the normal strength, it was considered to be good.

Japanese Unexamined Patent Publication No. 10-109379

However, in particular, the strength after boiling is an index related to reliability such as environmental resistance and long-term durability in the case of laminated glass, for example, and further improvement has been desired.
The present invention has been made under such circumstances, and an object of the present invention is to provide an adhesive for a glass laminate, which maintains transparency and can be firmly adhered to an interlayer film such as glass or a resin sheet. And.

As a means for solving the above problems, the present invention makes it possible to further improve the adhesiveness to glass while maintaining transparency by using an adhesive containing a fluororesin having a specific complex elastic modulus and an acrylic resin. It is intended to provide an adhesive.

That is, the present invention provides the following [1] to [4].
[1] Includes 40 to 80% by mass of the fluororesin (A) and 60 to 20% by mass of the acrylic resin (B), and the complex elastic modulus of the fluororesin ⁽ A) at 105 ° C. is 0.1 × 105 Pa. An adhesive for a glass laminate, characterized in that it is s or more.

[2] The fluororesin (A) is obtained by polymerizing 30 to 60% by mass of vinylidene fluoride and 70 to 40% by mass of tetrafluoroethylene and hexafluoropropylene in total, according to [1]. The described adhesive for glass laminates.

[3] The fluororesin (A) is obtained by polymerizing 30 to 60% by mass of vinylidene fluoride, 30 to 70% by mass of tetrafluoroethylene and 0 to 30% by mass of hexafluoropropylene, [1] or. The adhesive for a glass laminate according to [2].

[4] A fluororesin sheet for a glass laminate having a layer containing the adhesive according to any one of [1] to [3] on at least one side of the fluororesin sheet (C).

[5] A glass laminate having at least three layers of glass, a layer containing the adhesive according to any one of [1] to [3], and a fluororesin sheet (C) in this order.

According to the present invention, it is possible to provide an adhesive having both transparency and good adhesiveness to glass.

Hereinafter, the present invention will be described in detail.
The adhesive of the present invention contains 40 to 80% by mass of the fluororesin (A) and 60 to 20% by mass of the acrylic resin (B), and the complex elastic modulus of the fluororesin (A) at 105 ° C. is 0.1 × It is ¹⁰⁵ Pa · s or more. When the complex elastic modulus of the fluororesin (A) is in the above range, the adhesive strength after boiling can be improved.

The content ratio of the fluororesin (A) and the acrylic resin (B) is preferably 45 to 75% by mass for the fluororesin (A) and 55 to 25% by mass for the acrylic resin (B), and more preferably the fluororesin (). A) is 50 to 75% by mass, acrylic resin (B) is 50 to 25% by mass, and more preferably fluororesin (A) is 55 to 70% by mass and acrylic resin (B) is 45 to 30% by mass. be. By setting the fluororesin (A) to 40% by mass or more (acrylic resin (B) to 60% by mass or less), the adhesiveness with a resin sheet such as the fluororesin sheet (C) described later becomes good, and the fluororesin By setting (A) to 80% by mass or less (acrylic resin (B) is 20% by mass or more), the adhesiveness with glass described later is improved.

[Fluororesin (A)]
The fluororesin ⁽ A) has a complex elastic modulus at 105 ° C. of 0.1 × 105 Pa · s or more. By setting the complex elastic modulus to 0.1 × ¹⁰⁵ Pa · s or more, the adhesive layer is less likely to be deformed, and in the case of laminated glass, for example, reliability such as environmental resistance and long-term durability is improved. The environmental resistance and long-term durability can be specifically evaluated by the difficulty of lowering the adhesive strength (boil strength) after boiling. The complex elastic modulus is preferably 0.5 × 10 ⁵ Pa · s or more, more preferably 1 × 10 ⁵ Pa · s or more, still more preferably 10 × 10 ⁵ Pa · s or more, and preferably 40 × 10 ⁵ Pa · s or more. Pa · s or less, more preferably 30 × 10 ⁵ Pa · s or less, still more preferably 25 × 10 ⁵ Pa · s or less.
The complex elastic modulus is a value calculated by measuring the stress when a torsional deformation of 0.1% is applied at a frequency of 1 Hz in accordance with JIS K7244-10 (2005).

As a method for setting the complex elastic coefficient of the fluororesin (A) at 105 ° C. to 1 × 10 ⁵ Pa · s or more, for example, the type and ratio of the monomer components used in the production of the fluororesin (A) are adjusted, specifically. Is a method of adopting vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene as a monomer component and increasing the ratio of tetrafluoroethylene, hexafluoropropylene component, etc. to vinylidene fluoride to increase the crystallinity and melting point. However, it is necessary to adjust the composition ratio and the like so as not to impair the transparency and the formability of the adhesive layer. In addition, a cross-linking agent may be added during the production of the fluororesin (A) to facilitate the formation of a cross-linked structure, aromatic rings such as benzene ring and naphthalene ring, alicyclic rings such as cyclopentane and cyclohexane, and imide bonds. Examples thereof include a method of introducing a highly polar bond of the above, a highly polar group such as a halogen, etc. into the fluororesin (A). Further, a method of dispersing crystals by adding a nucleating agent is also effective. Among these methods, a method of adjusting the composition ratio of the monomer components constituting the fluororesin (A) is preferable.

The fluororesin (A) is not particularly limited as long as it contains fluorine, but a fluororesin (A) obtained by polymerizing a monomer component containing vinylidene fluoride is preferably used. Specifically, those obtained by polymerizing a monomer component containing 30 to 60% by mass of vinylidene fluoride and 70 to 40% by mass in total of tetrafluoroethylene and hexafluoropropylene are preferable. More preferably, vinylidene fluoride (33 to 55% by mass) and tetrafluoroethylene and hexafluoropropylene totaling 67 to 55% by mass, more preferably vinylidene fluoride (35 to 50% by mass), tetrafluoroethylene and hexafluoropropylene. It is made by polymerizing 65 to 50% by mass in total.

More specifically, the ratio of these monomer components is preferably 30 to 60% by mass for vinylidene fluoride, 30 to 70% by mass for tetrafluoroethylene, and 0 to 30% by mass for hexafluoropropylene. A more preferable ratio is 33 to 55% by mass of vinylidene fluoride, 33 to 60% by mass of tetrafluoroethylene, 0 to 27% by mass of hexafluoropropylene, and a more preferable ratio is 35 to 50% by mass of vinylidene fluoride. Tetrafluoroethylene is 45 to 65% by mass, and hexafluoropropylene is 0% by mass or more and less than 20% by mass.
The fluororesin (A) may contain other monomer components as long as the effects of the present invention are not impaired.

The melting point of the fluororesin (A) is preferably 95 ° C. or higher, more preferably 100 ° C. or higher, still more preferably 105 ° C. or higher, preferably 145 ° C. or lower, and more preferably 140 ° C. or lower. By DSC measurement, the melting point was raised to 200 ° C. at 10 ° C./min for 1 minute, cooled to 20 ° C. at 10 ° C./min, held for 1 minute, and then held again at 10 ° C./min for 200 ° C. The peak top temperature of the melting peak observed when the temperature rises to ° C. When two or more melting peaks are observed, the peak top temperature of the melting peak on the high temperature side is taken as the melting point.

[Acrylic resin (B)]
The acrylic resin (B) is not particularly limited, but polymerizes a monomer component containing an ester of (meth) acrylic acid such as methyl, ethyl, propyl, butyl, isobutyl, n-hexyl, 2-ethylhexyl, lauryl or stearyl. And what you can get.
Among them, those obtained by polymerizing a monomer component in which 90% by mass or more of the monomer component is methyl methacrylate are more preferable. By setting the methyl methacrylate component to 90% by mass or more, the adhesiveness with glass tends to be good. When methyl methacrylate and other monomer components are mixed and used, as the other monomer components, methylacrylate, butylacryllate, butylmethacrylate, isobutylmethacrylate and the like are preferably used. can. Further, an acid monomer such as acrylic acid, methacrylic acid, fumaric acid, and itaconic acid may be added in order to further improve the adhesiveness with glass.

In the present invention, it is preferable that the fluororesin (A) and the acrylic resin (B) have good compatibility from the viewpoint of transparency and adhesive strength. In that respect, it is preferable to use a fluororesin obtained by polymerizing vinylidene fluoride, which has good compatibility with the acrylic resin, as a monomer component. Further, the compatibility can be adjusted by incorporating the above-mentioned copolymerization component into both resin components or adjusting the molecular weights of both components. The number average molecular weight of the fluororesin (A) is preferably in the range of 40,000 to 150,000, and the number average molecular weight of the acrylic resin (B) is preferably in the range of 2000 to 50,000.

The adhesive of the present invention is used as an adhesive for a glass laminate. When used, the adhesive of the present invention may be directly applied to the glass for use, or the fluororesin sheet (C) described later may be formed on one or both sides of the fluororesin sheet (C) and used. From the viewpoint of processability of the glass laminate, it is preferable to form a layer containing the adhesive of the present invention on one side or both sides of the fluororesin sheet (C) and use it as an adhesive sheet for the glass laminate.

[Fluororesin sheet (C)]
In the present invention, as described above, it is preferable to use a sheet having a layer containing the adhesive of the present invention on at least one side, preferably both sides of the fluororesin sheet (C) as an adhesive sheet for a glass laminate. By using such a fluororesin sheet as an adhesive sheet, the workability of the glass laminate is improved, and the appearance finish with less air bubbles is likely to be obtained, which is preferable.

The fluororesin sheet (C) is not particularly limited as long as it contains fluorine, but the monomer components include vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, pentafluoropropylene, hexafluoropropylene and the like. Examples thereof include homopolymers or copolymers of the fluoropolymers of the above, copolymers in which vinyl monomers such as ethylene and alkyl vinyl ether are used in combination with the fluoropolymers, or mixtures thereof. Specifically, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-vinylidene fluoride-hexafluoropropylene co-weight. Examples thereof include coalescence, polyvinylidene fluoride, and polyvinyl fluoride.

When obtaining fireproof glass, it is preferable to select a fluororesin sheet (C) having a fluorine content of 55% by mass or more, preferably 60% by mass or more in order to secure flame retardancy. It is preferable to use a fluororesin sheet (C) containing a component common to the fluororesin (A) in the above-mentioned adhesive, preferably vinylidene fluoride, because the adhesiveness with the adhesive is higher. Particularly preferable fluororesin sheet (C) includes ternary copolymers of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene. The preferable copolymerization ratio of this ternary copolymer is in the range of 20 to 40% by mass of vinylidene fluoride, 20 to 60% by mass of tetrafluoroethylene, and 5 to 20% by mass of hexafluoropropylene. This copolymer sheet has low crystallinity and good transparency, is flexible and has excellent impact resistance, and has a relatively low melting point, so that it is suitable for heat fusion with glass.

The thickness of the fluororesin sheet (C) is not particularly limited, but is preferably in the range of 50 to 2000 μm in consideration of the influence on the impact resistance when laminated with glass. The fluororesin sheet (C) may be molded by a generally known method. For example, the fluororesin is dissolved in an organic solvent, uniformly applied onto a peelable substrate, and then the organic solvent is dried and removed. Then, it is peeled off from the base material to form a sheet, a method of uniformly applying an aqueous dispersion of fluororesin on a peelable base material and then drying water, or a heat of an extrusion molding method, a calendar molding method, or the like. A method of forming a sheet by plastic molding or the like is possible. Above all, from the viewpoint of productivity, it is preferable to adopt the extrusion molding method.
Various additives can be added to the fluororesin sheet (C) within a range that does not impair the characteristics of the fluororesin sheet, particularly transparency.

[Glass]
The glass is not particularly limited, and conventionally known ones can be used. For example, a meshed glass in which a metal net is embedded in the middle of the wall thickness over the entire surface of the glass plate, and a glass plate as a softening point of the glass are used. Examples thereof include wind-cooled reinforced soda-lime glass and wind-cooled borosilicate glass, which are reinforced by applying compressive stress to the surface layer of the glass plate by blowing cooling air at a high pressure after heating at the above temperature. In addition to the above, fireproof glass obtained by ion-exchange treatment of SiO ₂ -Al ₂ O ₃ -B ₂ O ₃ system glass and SiO ₂ -Al ₂ O ₃ -Li ₂ O system glass and the like can be mentioned.
These fireproof glasses may have functional layers such as a heat ray reflecting layer, an antioxidant layer, and an antifog layer formed on one side or both sides thereof, if necessary.
Such fireproof glass is generally available, and examples thereof include "Firelight" manufactured by Nippon Electric Glass Co., Ltd.

[Glass laminate]
The glass laminate of the present invention can be produced by adhering the glass to another member such as an interlayer film using the adhesive of the present invention. A glass laminate having at least three layers of glass, a layer containing an adhesive, and a fluororesin sheet (C) in this order is preferable.
In order to obtain such a glass laminate, as described above, a layer containing the adhesive of the present invention (hereinafter, may be referred to as an "adhesive layer") is formed on the surface of the glass, and a fluororesin sheet (hereinafter, may be referred to as an "adhesive layer") is formed. It is preferable to use a method of heat-pressing with C) to fuse the adhesive layer, or a method of forming the adhesive layer on the surface of the fluororesin sheet (C) and heat-pressing the adhesive layer with glass to fuse the adhesive layer.

The method for forming the adhesive layer is not particularly limited, but the above-mentioned adhesive containing the fluororesin (A) and the acrylic resin (B) is dissolved in an organic solvent and is formed on the surface of the glass or the fluororesin sheet (C). A method of uniformly applying and then heating and drying to form a direct film, or a method of uniformly applying the above adhesive solution on a peelable substrate such as polyethylene terephthalate and drying, and then the fluororesin sheet (C). A method of transferring and forming by heat fusion with and the like can be adopted.
An ultraviolet absorber, a pigment, a plasticizer, a surfactant, a silane coupling agent, an impact improver, etc. are added to this adhesive solution as a third component within a range that does not impair the adhesiveness and transparency. It is possible.

When forming an adhesive layer on the fluororesin sheet (C), if there is a risk of wrinkling on the surface of the fluororesin sheet, a peelable base material such as polyethylene terephthalate is laminated on the back surface of the fluororesin sheet to form a "waist". A method of peeling off the peelable base material after forming the adhesive layer can be preferably adopted. If the peelable base material is used when forming the fluororesin sheet (C), it can be used as it is. can.

When forming an adhesive layer on the surface of the fluororesin sheet (C), the surface of the fluororesin sheet (C) is previously subjected to corona discharge treatment and plasma in order to improve the adhesiveness between the fluororesin sheet (C) and the adhesive layer. It can also be etched or oxidized by a method such as discharge treatment or sodium-ammonia treatment.

According to the adhesive of the present invention, glass and an interlayer film such as a fluororesin sheet can be laminated firmly and while maintaining transparency, so that the obtained laminate is required to have high reliability for fire protection. It can be suitably used for safety glass and the like.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

[Manufacturing of fluororesin sheet (C)]
A copolymerized fluororesin obtained by polymerizing a monomer component of 40% by mass of vinylidene fluoride, 40% by mass of tetrafluoroethylene, and 20% by mass of hexafluoropropylene is extruded by an extruder to obtain a fluororesin sheet (C) having a thickness of 500 μm. ) Was obtained.

(Example 1)
As an adhesive, a fluororesin (A) (melting point 135 ° C.) obtained by polymerizing a monomer component of vinylidene fluoride 40% by mass and 60% by mass tetrafluoroethylene, methylmethacrylate 95% by mass, and ethylmethacrylate. Acrylic resin (B) obtained by polymerizing a monomer component of 5% by mass of the rate was blended at a mass ratio of 70:30, and 3-aminopropyltriethoxysilane was used as a silane coupling agent as the component (A). And (B) were blended in an amount of 1 part by mass with respect to 100 parts by mass in total. This adhesive is dissolved in a mixed solvent of butyl acetate and methyl isobutyl ketone (mass ratio 75:25), coated on the fluororesin sheet (C) with a coater, and heated in a heating furnace at 120 ° C. for 30 seconds. The solvent was removed by drying to obtain a fluororesin sheet having an adhesive layer having a thickness of 0.5 μm on one side of the fluororesin sheet (C). The complex elastic modulus of the fluororesin ⁽ A) at 105 ° C. was 20 × 105 Pa · s.

(Example 2)
As the fluororesin (A), a fluororesin (melting point 112 ° C.) obtained by polymerizing a monomer component of vinylidene fluoride 40% by mass, tetrafluoroethylene 40% by mass and hexafluoropropylene 20% by mass was used, and an acrylic resin (melting point 112 ° C.) was used. As B), an acrylic resin obtained by polymerizing a monomer component of 100% by mass of methyl methacrylate was used, and the content ratio of both was set to 55:45 in the mass ratio in the same manner as in Example 1. A fluororesin sheet was obtained. The complex elastic modulus of the fluororesin ⁽ A) at 105 ° C. was 1.0 × 105 Pa · s.

(Comparative Example 1)
Except for using a fluororesin (melting point 89 ° C.) obtained by polymerizing a monomer component of 61% by mass of vinylidene fluoride, 24% by mass of tetrafluoroethylene, and 15% by mass of hexafluoropropylene as the fluororesin (A). A fluororesin sheet was obtained in the same manner as in Example 1. The complex elastic modulus of the fluororesin (A) at 105 ° C. was 2 × 10 ³ Pa · s.

[Evaluation of fluororesin sheet]
For each fluororesin sheet produced in the above-mentioned Examples and Comparative Examples, (a) adhesiveness and (b) transparency were evaluated as follows.

(A) Adhesiveness 1) Preparation of sample A 5 mm (150 mm × 50 mm) thick firelite (crystallized glass plate manufactured by Nippon Electric Glass Co., Ltd.) and a fluororesin sheet obtained by the above method are used. The adhesive layers were layered so as to face the glass surface, and pressed and heated for 30 minutes at 145 ° C. and 127 N / cm ² with a hot press to bond them together.

2) Normal strength Two notches are made on the surface of the fluororesin sheet bonded by the method described in 1) above at intervals of 18 mm, and the fluororesin sheet between the notches is parallel to the notch direction and is 180 at 23 ° C. Peeling was performed at an angle of ° at a speed of 5 mm / min, and the adhesive strength (N) at that time was taken as the normal strength.

3) Boil strength Two notches are made on the surface of the fluororesin sheet bonded by the method described in 1) above at intervals of 18 mm, and the obtained notched fluororesin sheet is immersed in boiling water at 100 ° C. for 2 hours. The resin was taken out and the adhesive strength was measured in the same manner as in the method described in 2) above to determine the boil strength.

(B) Transparency The total light transmittance (maximum measured value at a wavelength of 400 to 700 nm) of a laminate of glass and a fluororesin sheet produced by the same method as in the evaluation of (a) adhesiveness was measured and evaluated. ..

The evaluation results for Examples and Comparative Examples are shown in Table 1 below.

As is clear from the results shown in Table 1, the glass laminate provided with the adhesive layer having a complex elastic modulus of 0.1 × ¹⁰⁵ Pa · s or more of the fluororesin (A) has a small decrease in boil strength. Understand (Examples 1 and 2).
On the other hand, when the complex elastic modulus of the fluororesin (A) is lower than the range of the present invention, it can be seen that the boil strength is significantly reduced and the adhesiveness is inferior (Comparative Example 1).

Claims (6)

It contains 40 to 80% by mass of the fluororesin (A) and 60 to 20% by mass of the acrylic resin (B), and the complex elastic modulus of the fluororesin ⁽ A) at 105 ° C. is 0.1 × 105 Pa · s or more 40 . × 10 ⁵ Pa · s or less ,
The acrylic resin (B) is an adhesive for a glass laminate, characterized in that 90% by mass or more of the monomer component thereof is methyl methacrylate . The glass according to claim 1, wherein the fluororesin (A) is obtained by polymerizing 30 to 60% by mass of vinylidene fluoride and 70 to 40% by mass of tetrafluoroethylene and hexafluoropropylene in total. Adhesive for laminates. The present invention according to claim 1 or 2, wherein the fluororesin (A) is obtained by polymerizing 30 to 60% by mass of vinylidene fluoride, 30 to 70% by mass of tetrafluoroethylene and 0 to 30% by mass of hexafluoropropylene. Adhesive for glass laminates. A fluororesin sheet for a glass laminate having a layer containing the adhesive according to any one of claims 1 to 3 on at least one surface of the fluororesin sheet (C). The fluororesin sheet for a glass laminate according to claim 4, wherein the fluororesin sheet (C) is formed by polymerizing a monomer component containing vinylidene fluoride. A glass laminate having at least three layers of glass, a layer containing the adhesive according to any one of claims 1 to 3, and a fluororesin sheet (C) in this order.