JPS6151542B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a laminate of a plastic film and a glass plate used for insulation of window glass, and more specifically to a foamed resin layer and a non-foamed resin layer having a mesh structure or Japanese paper-like texture. The present invention relates to a laminate of a multilayer plastic film and a glass plate, comprising at least two layers. The first object of the present invention is to provide a plastic film that has both heat insulating properties and transparency without using special and expensive materials. The second object of the present invention is to have a texture similar to a lace curtain, moderate transparency, excellent heat insulation and heat retention, scatter direct sunlight, and reduce the amount of sunlight entering the room at night. Another object of the present invention is to provide a laminate of a plastic film and a glass plate that is effective in reducing the leakage of indoor illumination light to the outside of a window.
Traditionally, as an energy-saving building material,
Plastic films that adhere to window glass have been proposed. For example, as shown in JP-A-53-34880 and JP-A-53-141382, a metal film is vapor-deposited on a plastic film and is attached to a window glass to reflect the heat rays of sunlight. Films and the like have been proposed that prevent infrared rays from emitting indoors to the outside by reflecting them. However, these plastic films have a complicated structure and are expensive, and in terms of performance, it is almost impossible to reduce the thermal conductivity of glass windows with these films, so they have no effect on helping air conditioners in the summer. Even if there is, the effect of promoting the heating effect in winter is extremely weak. Furthermore, since these heat radiation blocking films are transparent, it is not possible to control the intensity of visible light rays or freely control transparency. The inventors of the present invention have conducted various studies to develop a plastic film for window glass that can be easily produced through a simple process and has high heat insulation properties. In the multilayer stretched film produced by the inflation method, some or all of the cells in the foamed resin layer burst during the expansion and stretching process of the inflation bubbles, forming an uneven network structure. When attached to a window glass with the resin layer facing the glass plate,
Although it has transparency comparable to that of lace curtains,
They discovered that it has the effect of significantly increasing the indoor heating effect in winter, and further research led to the completion of the present invention. The multilayer plastic film used in the laminate of the present invention is a multilayer plastic film manufactured by a coextrusion stretching method, and is a multilayer plastic film consisting of at least two layers, a foamed resin layer and a non-foamed resin layer, and the foamed resin layer is Located in the outermost layer, the bubbles in the foamed resin layer are stretched and oriented to become flat, and some or all of the bubbles burst, forming an uneven network structure in the foamed resin layer. It is characterized by a diameter of 2 mm to 20 mm along the film surface. The main component of the foamed resin layer is preferably polypropylene, low density polyethylene, high density polyethylene, ethylene monovinyl acetate copolymer resin, ionomer or styrene resin, with porpropylene and low density polyethylene being particularly preferred.
The foaming method of the foamable resin is not particularly limited, but examples of chemical foaming agents include sodium bicarbonate, azodicarbonamide, P-toluenesulfonyl semicarbazide,
Trihydrazinotriazine and the like are preferred. The foaming agent is preferably contained in the resin composition in an amount of 0.1 to 2% by weight. Usually, it is preferable to add about 0.3 to 1% of a blowing agent to the resin pellets, dry blend them, and then charge them into the hopper of an extruder. In addition, a high-concentration blowing agent is added to the resin and pre-kneaded in an extruder to produce a masterbatch, which is then mixed with regular resin pellets during film production using an extruder for co-extrusion and stretching equipment for film production. It may be supplied to
The non-foamed resin layer is made of polypropylene, low density polyethylene, high density polyethylene, ionomer resin,
Examples include ethylene-vinyl acetate copolymer resin, polybutadiene resin, thermoplastic polyester resin, and vinyl chloride resin, with low-density polyethylene, polypropylene, polyester, and the like being particularly preferred. The film used in the laminate of the present invention can be manufactured for the first time by a coextrusion stretching method that combines a foamed resin layer and a non-foamed resin layer. Stretching methods are preferred, especially coextrusion inflation methods. A method of producing a film with only a foamed resin layer by the inflation method is well known, but in such a single layer inflation method with only a foamed layer, a large number of bubbles are formed on the film surface due to the bursting of the foamed resin bubbles. When the through hole is formed, air escapes from the inflatable tube, the inflatable tube contracts, and the tube is expanded and stretched due to the difference in air pressure inside and outside the inflatable tube, thereby producing a film having the structure and texture of the present invention. becomes impossible. In order to create a film with a mesh structure or Japanese paper-like texture in which some or all of the cells in the foamed resin layer burst as in the present invention, the foamed resin layer and the non-foamed resin layer are coextruded. It is essential to carry out co-stretching. When producing the film used for the laminate used in the present invention by the coextrusion inflation method, the molten laminated tube extruded from the cylindrical lamination die is blown out from the die lip by each layer of foamed resin. An increase in the size of the bubbles occurs. At the same time, the tube expands due to the pressure difference between the inside and outside of the tube, stretches in the drawing direction, and bursts some or all of the cells in the foamed resin layer, thereby causing the foamed resin layer adjacent to the non-foamed resin layer to expand. A mesh-like or Japanese paper-like structure and texture is formed. In this case, each cell in the foamed resin layer is sufficiently stretched and flattened, and further, some or all of the cells are ruptured. If the bubbles are not expanded flat due to the stretching orientation and the bubbles do not burst, the foam structure will be similar to a known foam sheet, which is an aggregation of microscopic bubbles, and the transparency will be reduced, resembling a lace curtain. The texture will disappear, and the insulation properties will decrease when laminated to a glass plate. When manufacturing film using the inflation method, the final blow ratio must be reached to 3 or higher in order to sufficiently burst the bubbles in the foamed resin layer and form a thin, large-mesh structure on the surface of the film. It is desirable to increase the take-up ratio as well. In order to impart heat shrinkability to the film, in the case of the air-cooled inflation method, it is preferable that the final blow ratio is 4 or more and the take-off ratio is also 4 or more. The film used in the laminate of the present invention has a foamed resin layer that has an uneven network structure or Japanese paper-like texture, and has a unique appearance not found in conventional films. Highly sexual. The network of the foamed resin layer varies depending on the type and composition of the foamed resin, the type and composition of the non-foamed resin, extrusion conditions during coextrusion, stretching ratio during costretching, film cooling conditions, take-up speed, etc. It is possible to create various changes in the size and distribution of the mesh in the structure, the shape and distribution of the mesh, and the degree of irregularity of the mesh, as well as the texture, pattern, transparency, color, and light reflection of Japanese paper. A wide variety of changes can be made in the ratio, hardness and flexibility of the film, degree of unevenness of the foam layer, etc. Therefore, by laminating this film on a glass plate, it is possible to create a laminate with various patterns depending on the type of film, and transparency can be easily controlled by combining with the film. Furthermore, by laminating two or more films on glass, new patterns can be formed and the insulation properties can be improved. When laminating this film on a glass plate, it is best to stack the film with the foamed resin side facing the glass plate.It has high heat insulation properties and has the same transparency and light blocking effect as lace curtains, making it suitable for window glass. A laminate can be formed. When a foamed resin layer with an uneven mesh-like or Japanese paper-like structure comes into contact with the glass plate surface, a layer of air with a thickness corresponding to the height of the unevenness of the network structure is created between the glass plate surface and the non-foamed resin layer. A layer is formed. The air layer formed between the glass plate and the non-foamed resin layer is confined in an almost independent area for each unit of the network structure, so the air inside the unit can freely flow. Since it cannot move, it is thought that air convection is difficult to occur.
Air layers conduct heat less easily than glass plates or plastics, so laminates can significantly improve insulation. By laminating a film with a network structure having an average diameter of 2 mm to 20 mm along the film surface on glass, transparency,
A laminate with a good balance between texture and heat insulation and heat retention can be obtained. For the reasons mentioned above, the insulating effect of the laminate of the present invention is extremely good, and the indoor heat retention is good. When this laminate is used for windows, it can prevent cold air from entering in the winter and can be used for heating. The amount of energy required can be significantly reduced, and the indoor cooling effect can be increased in the summer, and energy consumption can also be significantly reduced. A method of attaching an opaque foam film to a glass window to increase heat insulation has been known, but since the conventional foam film is opaque and has a considerable thickness, it is generally difficult to attach it to the window glass. It has not yet come into widespread use. In the northern countries, window glass and several centimeters
Efforts have been made to increase the insulation effect by fixing plastic film to the window frame at intervals of
This also has not become widely popular due to its unsightly appearance and the inability to open and close windows freely. In contrast, the laminate of the present invention has a film that tightly adheres to the glass plate, has extremely high heat insulation properties, good transparency, and has a texture similar to a lace curtain or patterned glass. hand,
It has the effect of looking good. It has been difficult to achieve such effects of the present invention using only a glass plate.
In addition, simply pasting a transparent plastic film on a glass plate has almost no insulation effect, whereas the film of the present invention can be manufactured at the same price as a normal transparent plastic film, and is easy to install. It is possible to create a number of features. Since it is easy to impart heat shrinkability to the film used in the laminate of the present invention, when attaching the film to a window glass, the peripheral portion of the film is attached to the peripheral portion of the glass plate or the window frame. After fixing, the unfixed portion at the center of the film is heated to shrink, thereby improving the flatness and adhesion of the film. When the foamed mesh layer is attached to the glass side using this method, a sufficient fixed layer of air can be formed between the film and the glass, the appearance is good, and the heat insulation effect is further enhanced. As a method for fixing the peripheral part of the film to the peripheral part of the glass plate, the glass plate and the film may be kept in close contact with each other and fixed to the window frame at the same time. When laminating the film to the glass plate, it is also preferable to interpose an adhesive layer on a part or the entire surface of the laminated surface using double-sided adhesive tape, transparent adhesive film, or the like. In this case, an adhesive resin may be laminated on one side of the film in advance, and this adhesive resin layer side may be attached to a glass plate. If the foam layer and the adhesive resin layer are adhered to such an extent that a sufficient air layer remains between them, the heat insulation properties will be improved. In the present invention, when laminating a film and a glass plate, the combination is not necessarily limited to only two films, and if necessary, another film may be interposed between the film of the present invention and the glass plate, The film of the present invention may be interposed between the glass plates. Examples will be described below. Example A film of the present invention comprising a foamed polypropylene layer produced by a coextrusion inflation method and a non-foamed low-density polyethylene layer was applied to window glass in winter to form a laminate of the film and glass, and indoors. The insulation and heat retention properties were measured. For the foamed resin layer of the multilayer plastic film of the example, a composition in which azodicarbonamide was added as a foaming agent to polypropylene resin was used. In the film manufacturing process, the cells in the foamed resin layer were sufficiently stretched and oriented to form a flat shape, and most of the cells were burst to form a network structure as shown in FIG. Figure 1 shows the mesh that can be seen through the film, and the diameter of the cells is 3 mm to 3 mm along the film surface.
It is about 10mm. FIG. 2 is a sketch of the cross-sectional structure of this film, in which mesh irregularities with a maximum height of about 250 μm are formed on a 40 μm thick film. In FIG. 2, numeral 1 indicates a non-foamed resin layer, and numeral 2 indicates the unevenness of the network structure due to the foamed resin layer. The foamed resin layer of this film was laminated on a glass plate with the foamed resin layer facing the glass plate surface. A cross-sectional view of this laminate is shown in FIG. In Figure 3, 3 is a glass plate;
4 is a foamed resin layer, 5 is a non-foamed resin layer, and 6 is an air layer formed between the film and the glass plate. In addition to the laminate of the present invention, for comparison, 1. A glass plate alone, 2. A commercially available low-density polyethylene film attached to a glass plate, and 3. A commercially available foamed polyethylene sheet and cellophane attached to a glass plate. The indoor insulation and heat retention properties were measured for each case when the laminate was attached. A room with a floor area of 47m ² and a height of 3m from floor to ceiling, with concrete walls on the east, west, and south sides, and a glass window on the north side that is 2m high and 6m wide from 1m from the floor to the ceiling. These films were pasted on the glass windows of 2017 and their heating effects were compared in the winter. The outdoor temperature was 5°C, and the room temperature at the center of the room at a height of 1.2 m above the floor was maintained at 25°C using a ventilated heating system.
At this time, the center of the 6 m wide glass window is 1.2 m above the floor.
The temperature was measured using an alcohol thermometer at a height of 1 cm from the glass window surface. Table 1 shows the measured temperatures when the film of the present invention was attached to the entire surface of the window glass, when a known film of a comparative example was attached, and when no film was attached. Each film was attached to a glass window by applying adhesive to the periphery of each film in a width of 2 cm in units of 1 m in length and 1 m in width. After the film of the present invention was pasted, the central part of the film was heated to shrink, and the film was brought into close contact with the glass plate surface as shown in FIG. Even after this film was attached to a glass window, the scenery outside the window could be seen clearly from inside the room, and the film had the texture of a lace curtain.

[Table] The thickness of the window glass was 2.5 mm. As is clear from Table 1, the laminate of the film and glass plate of the present invention has a remarkable effect on indoor heat insulation. It can be kept at the same room temperature.

[Brief explanation of the drawing]

FIG. 1 shows the network structure of the film used in the laminate of the present invention. FIG. 2 shows the cross-sectional structure of the film used in the laminate of the present invention, in which 1 indicates a non-foamed resin layer and 2 indicates a foamed resin layer. FIG. 3 shows a laminate of a film and a glass plate according to the present invention, in which numeral 3 indicates a glass plate, 4 indicates a foamed resin layer, 5 indicates a non-foamed resin layer, and 6 indicates an air layer.

Claims (1)

[Scope of Claims] 1. A multilayer plastic film consisting of at least two layers, a foamed resin layer and a non-foamed resin layer, in which the foamed resin layer is the outermost layer, and the cells in the foamed resin layer are stretched and oriented to become flat; Furthermore, some or all of the bubbles have burst, and the foamed resin layer forms a network structure with unevenness. A multilayer plastic film in which the average diameter of the mesh is 2 mm to 20 mm along the film surface is placed on a glass plate. A laminate of multilayer plastic film characterized by being formed by laminating with. 2. A multilayer plastic film laminate according to claim 1, wherein the multilayer plastic film is laminated with a glass plate with the surface of the foamed resin layer facing the glass plate surface. 3. The multilayer plastic film laminate according to claim 1 or 2, wherein the multilayer plastic film is a transparent film. 4. The multilayer plastic film is a heat-shrinkable film, and when the film is laminated with a glass plate, the peripheral part of the film and the peripheral part of the glass plate are brought into close contact and fixed, and then the central unfixed part of the film is laminated with the glass plate. A laminate of multilayer plastic films according to claim 1, 2 or 3, which is heated and shrunk to improve the flatness of the film. 5. Lamination of multilayer plastic films according to any one of claims 1 to 4, in which an adhesive layer is interposed on a part or the entire surface of the laminated surface when laminating the multilayer plastic film and the glass plate. body.