TECHNICAL FIELD

The present invention relates to an interlayer film for laminated glass, containing a light stabilizer, an ultraviolet ray screening agent, or an oxidation inhibitor. Moreover, the present invention relates to a laminated glass prepared with the interlayer film for laminated glass.

BACKGROUND ART

Since laminated glass generates only a small amount of scattering glass fragments even when subjected to external impact and broken, the laminated glass is excellent in safety. As such, the laminated glass is widely used for automobiles, railway vehicles, aircraft, ships, buildings and the like. The laminated glass is produced by sandwiching an interlayer film between a pair of glass plates.

As one example of the laminated glass, the following Patent Document 1 discloses an interlayer film having low yellowing tendency, high transmittance to UV-A rays and visible light, and low transmittance to UV-B rays. The interlayer film contains a polyvinyl acetal, a plasticizer, and an oxanilide type compound which is an UV absorber. Patent Document 1 indicates that the interlayer film may contain a phenolic oxidation inhibitor, and may contain a nonaromatic light stabilizer of HAS/HALS/NOR-HALS type, and may contain a dye.

The following Patent Document 2 indicates that laminated glass capable of suppressing occurrence of foaming and growth of foaming can be obtained.

RELATED ART DOCUMENTS

Patent Documents

Patent Document 1: US2012/0052310A1

Patent Document 2: WO2012/043816A1

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

In conventional laminated glass, a void can be generated in an interlayer film in an end part of the laminated glass. This void is likely to be generated particularly when light, heat and the like is applied to the laminated glass. The void is a recess part in which the interlayer film is lost in the end part of the laminated glass. The void is different from a foaming product generated by foaming as described in Patent Document 2.

In recent years, a covering material is sometimes not arranged on the upper end of laminated glass for use in an automobile for reducing the weight of the automobile. As a result, the interlayer film can be in an exposed condition, and rainwater can collect in the vicinity of the interlayer film, resulting that a void is easily formed on the upper end side.

When a void is generated in an interlayer film in an end part of laminated glass, the appearance of the laminated glass can be impaired, and the adhesive force between the interlayer film and the glass plate or the like can deteriorate.

In an interlayer film, a colored part called a shade region can be formed. In a conventional interlayer film, discoloration can occur in the colored part.

Further, in a conventional interlayer film, it is difficult to achieve both prevention of generation of a void in the interlayer film in an end part of laminated glass, and prevention of discoloration in the colored part.

An object of the present invention is to provide an interlayer film for laminated glass capable of preventing generation of a void in the interlayer film in an end part of laminated glass. It is also an object of the present invention to provide a laminated glass prepared with the interlayer film for laminated glass.

Means for Solving the Problems

According to a broad aspect of the present invention, there is provided an interlayer film for laminated glass (hereinafter, sometimes described as interlayer film) that has a lengthwise direction and a widthwise direction, and includes configuration A, configuration B or configuration C below.

Configuration A: containing a light stabilizer, and having such a distribution in content of the light stabilizer in the widthwise direction that the content of the light stabilizer is larger in one end side of the widthwise direction.

Configuration B: containing an ultraviolet ray screening agent, and having such a distribution in content of the ultraviolet ray screening agent in the widthwise direction that the content of the ultraviolet ray screening agent is larger in one end side of the widthwise direction.

Configuration C: containing an oxidation inhibitor, and having such a distribution in content of the oxidation inhibitor in the widthwise direction that the content of the oxidation inhibitor is larger in one end side of the u widthwise direction.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes the configuration A, and contains the light stabilizer in a first region extending for 5% inwardly from one end of the widthwise direction; does not contain or contains the light stabilizer in a second region extending for 5% inwardly from the other end opposite to the one end of the widthwise direction; and a content of the light stabilizer in the entire first region is larger than a content of the light stabilizer in the entire second region.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes the configuration B, and contains the ultraviolet ray screening agent in a first region extending for 5% inwardly from one end of the widthwise direction; does not contain or contains the ultraviolet ray screening agent in a second region extending for 5% inwardly from the other end opposite to the one end of the widthwise direction; and a content of the ultraviolet ray screening agent in the entire first region is larger than a content of the ultraviolet ray screening agent in the entire second region.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes the configuration C, and contains the oxidation inhibitor in a first region extending for 5% inwardly from one end of the widthwise direction; does not contain or contains the oxidation inhibitor in a second region extending for 5% inwardly from the other end opposite to the one end of the widthwise direction; and a content of the oxidation inhibitor in the entire first region is larger than a content of the oxidation inhibitor in the entire second region.

In a specific aspect of the interlayer film according to the present invention, the interlayer film has a colored part that is colored in plan view in one end side of the widthwise direction, and has a non-colored part that is not colored in plan view in the other end side opposite to the one end of the widthwise direction.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes the configuration A, and contains the light stabilizer in the colored part; does not contain or contains the light stabilizer in the non-colored part; and a content of the light stabilizer in the entire colored part is larger than a content of the light stabilizer in the entire non-colored part.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes the configuration B, and contains the ultraviolet ray screening agent in the colored part; does not contain or contains the ultraviolet ray screening agent in the non-colored part; and a content of the ultraviolet ray screening agent in the entire colored part is larger than a content of the ultraviolet ray screening agent in the entire non-colored part.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes the configuration C, and contains the oxidation inhibitor in the colored part; does not contain or contains the oxidation inhibitor in the non-colored part; and a content of the oxidation inhibitor in the entire colored part is larger than a content of the oxidation inhibitor in the entire non-colored part.

In a specific aspect of the interlayer film according to the present invention, a visible light transmittance of the colored part is lower than a visible light transmittance of the non-colored part.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes a plurality of layers in one end side of the widthwise direction.

In a specific aspect of the interlayer film according to the present invention, a number of layers in one end side of the widthwise direction is different from a number of layers in the other end side of the widthwise direction.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes a layer having a glass transition temperature of 10° C. or less.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes a first layer, and a second layer arranged on a first surface side of the first layer.

In a specific aspect of the interlayer film according to the present invention, the first layer has a glass transition temperature of 10° C. or less.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes the configuration A, and a content of the light stabilizer in the first layer is larger than a content of the light stabilizer in the second layer.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes the configuration B, and a content of the ultraviolet ray screening agent in the first layer is larger than a content of the ultraviolet ray screening agent in the second layer.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes the configuration C, and a content of the oxidation inhibitor in the first layer is larger than a content of the oxidation inhibitor in the second layer.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes a colored layer containing a coloring agent in the colored part, and the colored layer is embedded in the first layer, or embedded in the second layer, or arranged between the first layer and the second layer, or arranged on a side opposite to the first layer side of the second layer.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes the configuration A, and when the colored layer is embedded in the first layer, a content of the light stabilizer in the colored layer is smaller than a content of the light stabilizer in the first layer; when the colored layer is embedded in the second layer, a content of the light stabilizer in the colored layer is smaller than a content of the light stabilizer in the second layer; when the colored layer is arranged between the first layer and the second layer, a content of the light stabilizer in the colored layer is smaller than a content of the light stabilizer in the first layer, and a content of the light stabilizer in the colored layer is smaller than a content of the light stabilizer in the second layer; and when the colored layer is arranged on a side opposite to the first layer side of the second layer, a content of the light stabilizer in the colored layer is smaller than a content of the light stabilizer in the second layer.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes the configuration B, and when the ultraviolet ray screening agent is embedded in the first layer, a content of the ultraviolet ray screening agent in the colored layer is smaller than a content of the ultraviolet ray screening agent in the first layer; when the colored layer is embedded in the second layer, a content of the ultraviolet ray screening agent in the colored layer is smaller than a content of the ultraviolet ray screening agent in the second layer; when the colored layer is arranged between the first layer and the second layer, a content of the ultraviolet ray screening agent in the colored layer is smaller than a content of the ultraviolet ray screening agent in the first layer, and a content of the ultraviolet ray screening agent in the colored layer is smaller than a content of the ultraviolet ray screening agent in the second layer; and when the colored layer is arranged on a side opposite to the first layer side of the second layer, a content of the ultraviolet ray screening agent in the colored layer is smaller than a content of the ultraviolet ray screening agent in the second layer.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes the configuration C, and when the colored layer is embedded in the first layer, a content of the oxidation inhibitor in the colored layer is smaller than a content of the oxidation inhibitor in the first layer; when the colored layer is embedded in the second layer, a content of the oxidation inhibitor in the colored layer is smaller than a content of the oxidation inhibitor in the second layer; when the colored layer is arranged between the first layer and the second layer, a content of the oxidation inhibitor in the colored layer is smaller than a content of the oxidation inhibitor in the first layer, and a content of the oxidation inhibitor in the colored layer is smaller than a content of the oxidation inhibitor in the second layer; and when the colored layer is arranged on a side opposite to the first layer side of the second layer, a content of the oxidation inhibitor in the colored layer is smaller than a content of the oxidation inhibitor in the second layer.

In a specific aspect of the interlayer film according to the present invention, the colored layer is embedded in the second layer.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes a third layer arranged on a second surface side opposite to the first surface of the first layer.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes the configuration A, and a content of the light stabilizer in the first layer is larger than a content of the light stabilizer in the third layer.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes the configuration B, and a content of the ultraviolet ray screening agent in the first layer is larger than a content of the ultraviolet ray screening agent in the third layer.

In a specific aspect of the interlayer film according to the present invention, the interlayer film includes the configuration C, and a content of the oxidation inhibitor in the first layer is larger than a content of the oxidation inhibitor in the third layer.

In a specific aspect of the interlayer film according to the present invention, the interlayer film is an interlayer film to be arranged between a first lamination glass member and a second lamination glass member for use.

In a specific aspect of the interlayer film according to the present invention, the interlayer film is an interlayer film to be attached in an opening part between the external space and the internal space in a vehicle, and is an interlayer film to be attached to the opening part in such a manner that the second layer side of the second layer and the third layer is located on the external space side.

In a specific aspect of the interlayer film according to the present invention, the interlayer film is an interlayer film to be attached in an opening part between the external space and the internal space in a vehicle, and is an interlayer film to be attached to the opening part in such a manner that one end side of the widthwise direction is located on the upper side of the opening part.

In a specific aspect of the interlayer film according to the present invention, the interlayer film contains a thermoplastic resin.

In a specific aspect of the interlayer film according to the present invention, the thermoplastic resin is a polyvinyl acetal resin.

In a specific aspect of the interlayer film according to the present invention, the interlayer film contains a plasticizer.

According to a broad aspect of the present invention, there is provided a laminated glass including a first lamination glass member, a second lamination glass member and the interlayer film for laminated glass described above, the interlayer film for laminated glass being arranged between the first lamination glass member and the second lamination glass member.

In a specific aspect of the laminated glass according to the present invention, the laminated glass is used as side glass, roof glass or glass for backlight in automobiles.

In a specific aspect of the laminated glass according to the present invention, the laminated glass is laminated glass that is to be used as glass for windshield, and black coating is not applied on the making surface between interlayer film and a lamination glass member on the body side.

Effect of the Invention

The interlayer film for laminated glass according to the present invention has a lengthwise direction and a widthwise direction, and includes the configuration A, the configuration B or the configuration C. Since the interlayer film for laminated glass according to the present invention has the above configuration, it is possible to prevent generation of a void in the interlayer film in an end part of laminated glass.

