JP3035238B2 - Capsule type structure for retroreflective sheet - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a retroreflective sheeting cap.
The present invention relates to a cell type structure. The present invention is a capsule on the surface
Independent small void chambers that are sealed are provided adjacent to each other
Retroreflective sheet (hereinafter sometimes simply referred to as reflective sheet)
The present invention relates to an improvement in a capsule structure. 2. Description of the Related Art The background of the invention is as follows.
It is. Light incident on the sheet surface is retroreflected in the incident direction.
Reflective sheet for road sign and car number play
Widely used for Figure that has been used since ancient times
In the reflection sheet having the structure shown in FIG.
Light a and b incident on the glass beads 2 which are in close contact with
Transparent reflective film applied to beads and its lower surface with a certain thickness
Metal deposition supported through layer 3 and underneath support layer 5
It hits the surface 4 and is retroreflected. This transparent
The reflective film layer 3 has a uniform concentric arc shape with respect to the glass beads.
Ideally, it is applied with a thickness. For example,
The incident light at an incident angle of 0 ° is focused on the metal deposition surface.
In contrast to the film thickness, the incident light direction of b at an incident angle of 30 °
If the thickness of the reflective film layer in the direction is large, the incident light of b
Focus on the inside of the coating layer 3 and diffusely reflect on the metal deposition surface
This is because the angle characteristic of retroreflection is reduced. Only
The reflective film layer 3 is a thin layer of about 10 to 20 μm,
Is formed by applying a solution, so the surface of the paint
Attempts to flatten due to tension and contacts metal vapor deposition film 4
It is very difficult to make the surface to be concentric with the glass bead spherical surface
It is. Current JIS Standard Z-9117 and US Federal Regulations
Case LS-300C is intended for the above reflective sheet.
So that the angle of incidence is 30 °
In this case, an attenuation rate of about 50% is allowed. This generic
Capsules for a long time to eliminate the drawbacks of reflective sheets
A reflection sheet called a mold has been proposed. Capsule type
The structure of the reflection sheet is transparent as shown in FIGS.
Protective film 1, with a gap from the protective film 1
And arranged directly on the lower hemisphere
Glass beads 2 provided with a metal deposition film 4, below the glass beads 2
And a support filter in which glass beads 2 are embedded on the upper surface.
And the supporting film 5 and the protective film 1
Independently sealed small compartments with small area connected vertically
It consists of connecting walls 6 that are continuous in a plane mesh
ing. With such a structure, the transparent substrate shown in FIG.
Since it is not necessary to provide the film-forming layer 3, the thickness uniformity is deteriorated.
There is no need to keep in mind that the angle characteristics of the reflective sheet
Improve step by step. A typical example of a capsule-type reflective sheet is
For example, Japanese Patent Publication No. 40-7870 (U.S. Pat.
178). Tokiko 40-787
No. 0 discloses a manufacturing method and a structure of a reflection sheet.
Briefly described by 2 and 3, first, a temporary support (not shown)
Once a substantially hemispherical portion of the glass beads 2 is embedded in the layer,
Between the beads and the surface of the upper hemisphere
After depositing the metal films 4, 4 'on one side over the gap,
Support film 5 made of a thermoplastic polymer in close contact with this
Is applied and the surface thereof is covered with a heat-resistant film 8.
Peel off the temporary support layer on the opposite side and expose the glass beads
Biaxially stretched transparent protection on the hemisphere part without metal film
Laminate the film 1 to create the desired independent compartments 7,7
In a mold having a convex mesh pattern as illustrated in FIG.
Therefore, heat press from the heat resistant film 8 side,
The film 5 is melted by heat and partially formed with the transparent protective film 1.
The connecting walls 6 are formed in the same pattern as
A small compartment vacant room 7 is made. Like this protective film
1 for connecting the supporting film 5 with the connecting wall 6 in a mesh form
In addition, without using a separate bonding material
Although the structure using the system 5 itself is convenient,
The film material is resistant to use as this type of reflective sheet.
With sufficient strength and flexibility as a support layer
In addition, the necessary performance as an adhesive material, that is, the material itself
Sufficient cohesion and sufficient adhesion to protective film 1
Must have. Practical for such reflective sheet
The selection of suitable materials that can be
It is not enough to take into account the knowledge of the drug, many studies
Research is required, for example,
As a material of the film 5, a thermoplastic polymethyl methacrylate
Rate, biaxially stretched polymethyl meta as protective film 1
Acrylic films are selected and combined. Only
However, this known example has a few disadvantages. One of them is a seed
The connection is easily broken due to various external factors. sand
In other words, Japanese Patent Application Laid-Open No. Sho 52-110592 (U.S. Pat.
No. 025159), a reflection sheet of the known example is disclosed.
Uses a thermoplastic polymer as the supporting film
He points out that there is something inferior in durability. More
In Japanese Patent Publication No. 40-7870, hot melt
Mold thermoset polymer can be used as support film material
There is an abstract explanation to the effect that
Not. Also disclosed in Japanese Patent Publication No. 40-7870.
The reflection sheet is shown in FIG. 2 of the publication.
In addition, the metal deposition films 4 and 4 ′ serve as supporting films for the glass beads 2.
Through the gap between the lower hemisphere surface and the beads
It will soon be a layer. That is, a metal deposition film
Form an integral continuous surface. Such a structure remains
The gap between the beads on the surface of the reflection sheet.
Since the area of the metal deposition film 4 'is considerably large, the reflection sheet
Looks dark and dark. Therefore, the upper surface of the metal deposition film 4 '
As shown in Fig. 2, to prevent light from reaching
Chill type white pigment (TiO ₂ Beads) containing pigments such as
A coating layer 9 of a composite must be provided. Of this paint
A small amount is glass beads on the side where the metal deposition film 4 is applied.
Intervening between the surface of the hemisphere and the metal deposition film 4
The incident light is metallized through the glass beads
The tendency to prevent the light from reaching the reflective film is likely to occur. this
Has a tendency to reduce the retroreflectivity of light on retroreflective sheets.
Bring. By the way, in the Japanese Patent Publication No. 40-7870,
One of the aforementioned disadvantages of the disclosed reflective sheet, namely
A part of the thermoplastic polymer support film is used as a protective film.
To eliminate the drawbacks of poor durability
A known example of the purpose is disclosed in Japanese Patent Application Laid-Open No. 52-110592.
There is a gazette. In this publication, Japanese Patent Publication No. 40-7870
It is not a general statement that the bulletin mentions, but a support
The formulation specifically selected for the film material,
Disclosed in Japanese Patent Publication No. 40-7870.
A common acrylic thermoplastic polymer similar to
In particular, such as ultraviolet rays, electron beams and heat rays.
Monomer, polyethylene, which is polymerized and cured by irradiation
Glycol diacrylate, 2-cyanoethyl acryle
Mixed with 1,6-hexanediol diacrylate, etc.
Adopts a special combination of
Can significantly improve the adhesion to the protective film
Is taught. By special selection of the above materials,
Improved adhesion of support film to protective film
This is convenient, but this reflection sheet also has a few questions.
There is a title. That is, the support film of the above-mentioned known reflection sheet is used.
The connecting wall between the lum and the protective film
Sufficient adhesion at the interface between the support film and the protective film
Despite this, this point uses a thermoplastic support film.
Is different from the case of
The degree is not always enough. That is, in FIG.
As shown, when a peeling force is applied to this reflective sheet,
The fracture of the film is caused by the interface A between the supporting film material and the protective film.
Rather, BB 'of the connecting wall 6 is C
Occurs at -C '. This is the material of the support film 5.
In the connecting wall 6 formed by a part of
Considering that glass beads are mixed,
You. In addition, monomers such as photosensitive are added to the support film material.
Is destruction or peeling due to deterioration due to external light.
It can be said that the separation strength is easily reduced. Ma
Each of the above-mentioned known examples is a biaxially stretched film as a protective film.
Is used. This is the strength of the protective film and moisture resistance
A seemingly wise choice to improve transparency, transparency, etc.
Seem. However, the fact is that this is not the case.
Has been confirmed by the public. That is, the above-mentioned known example
The reflection sheet shows remarkable shrinkage by heating.
More specifically, Japanese Patent Publication No. 40-7870 and
And the support disclosed in Japanese Patent Application Laid-Open No. 52-110592.
Even if a film material or bonding material is used, for example, 9
After immersing in water at 3 ° C for 3 hours and immersing in water for 21 hours
If you repeat the above two or three times, the reflective sheet will shrink significantly
I will. In addition, at a high temperature of 145 ° C., only 1 or 2 minutes
The protective film 1 peels up and peels off due to the passage of the degree.
It is completely destroyed. In addition, metal
The deposited film is on the support film in the gap between the glass beads
The problem that arises from the existence of
The reflection sheet disclosed in Japanese Patent No. 110592 also solves the problem.
Not erased. Because of the invention described in this publication
Is the binder or support film 5 of the known example described above.
From thermoplastic polymer to hot melt type thermosetting poly
Just changing it to a
You. Not only the known thermosetting support film material
To make a reflective sheet using
An ultraviolet irradiation device or heat
After attaching special equipment such as X-ray irradiator and heating the connecting wall
Irradiation work must be performed for a certain period of time. for example
For example, Examples 1-3 of JP-A-52-110592,
In 5-10 and 12-14, 19 using an electron beam irradiation device.
Irradiation with 1.5 Krad of 0 KV electron beam was performed.
For curing the support film, use an ultraviolet irradiation device at 50 m / min.
Two passes at speed. In Example 11, the heating was performed.
Heat the support film by heating at 65 ° C for 16 hours using an apparatus.
Although hardening is performed, even in this publication,
Thermal cure over time is stated to be undesirable. This
Requires a special process for curing.
What is needed is one major disadvantage in manufacturing. SUMMARY OF THE INVENTION The object of the present invention is to
To solve the problems of the known technology
Support film and protective film that are excellent and difficult to break even
Novel Capsule Type Structure for Retroreflective Sheet
In providing structures. Means for Solving the Problems The present invention provides a protective film.
And the supporting film are melted by the supporting film.
That are partially connected by connecting walls
The inside enclosed by the connecting wall 6 is a sealed independent casing.
A retroreflective sheeting forming a cubic small compartment
A pressel-type structure, wherein the support film has an upper layer side.
Having a laminated structure of at least two layers of a layer and a lower layer,
Different composition and composition for the upper layer and the lower layer
The upper layer is connected by the above melt molding
A pair with good adhesion to the protective film when the wall is formed
The lower layer has good adhesion to the upper layer
And a composition that exhibits greater resistance to breaking force
Capsule type structure for retroreflective sheeting characterized by having
Related to the structure. In addition, the present invention preferably provides a support filter.
The polymer composition that forms the upper layer of the
Isocyanate more than the polymer composition forming the side layer
The content of active groups that react with crosslinkable components such as
And a capsule-type structure for a retroreflective sheet. Departure
Akira's retroreflective sheeting capsule structure is disclosed in
Japanese Patent Application Laid-Open No. 110592 discloses a special feature.
No additional irradiation equipment is required,
Manufactured by the simple manufacturing method disclosed in Japanese Patent Publication No. 70
be able to. Finished product before applying release paper for shipping
The structure of an example is as shown in FIG. That is,
The protective film 1 and the support film 5 are
Partially connected by connecting wall 6 made by heat molding of 5
The inside surrounded by the wall 6 is a sealed independent sub-district
An image space 7 is formed. On its inner surface, for example,
Glass bead half-buried in the upper layer 5A of the holding film 5
The hemispherical surface of the beads 2 is exposed in the vacant space 7, and the metal deposition of the beads 2 is performed.
The substantially hemispherical surface covered by the film can be a reflecting surface.
These points are the same as the conventional capsule-type reflective sheet.
You. The support film in the present invention is in contact with the protective film.
The adhesion must be good. This adhesive force is
It may not be unilaterally determined solely by the composition of the main components of LUM.
Is determined by the correspondence with the composition of the protective film.
You. One of the best combinations is to use an acrylic copolymer
The main component is a protective film and the main component is acrylic
It is a combination of a support film that is a polymer. But,
The present invention is not limited to the above combinations, but
And a protective film made of an appropriate polymer
Any combination with a support film made of polymer
No. Therefore, for example, the main component of
The main component of the supporting film is carbonate or vinyl chloride.
To saturated polyester or linear polyurethane
Is also allowed. Support film is room temperature solid and thermoplastic
It is a fluid state where the connecting wall can be formed by heating.
However, after molding, it is preferably crosslinked and cured at room temperature.
It is desirable that the material be cured
No. In particular, in the present invention, the crosslinking-reactive polyisocyanate
OH groups that allow crosslinking by bonding
Support film of thermoplastic copolymer having active groups such as
Is preferably used as the main component. Room temperature curing type hot
Long time for curing by using the adhesive
If it is possible to omit all heating means, electron beam irradiation means, etc.
Method for producing capsule-type structure for retroreflective sheet of the present invention
Is extremely advantageous. In the present invention, the above support
Inside the thin connecting wall that connects the film and the protective film
Part strength and breakage due to internal cohesive failure
To prevent this, the supporting films must have at least
Also has a combined structure including the upper layer side and the lower layer side.
In this case, the composition of the upper layer side of the support film is a protective film
And good affinity with the lower layer
Advantageously, they are both good and can be integrated. I
Therefore, the polymer as the basic component of both layers is of the same type
It is desirable that For example, the same three or four
And an acrylic copolymer of a branched polymer. Branch
The holding film improves the adhesion to the protective film,
To increase the strength of BB ', melt viscosity during melt molding
Lower the protective film and the glass beads
Need to be However, so lower the melt viscosity
Then, the support film is stretched, and the C-C 'portion of FIG.
Therefore, there is a contradiction that this portion is easily broken. This
This is a disadvantage of the known art. The present inventor considers the above points.
Considering the support film layer, the upper layer with at least different properties
Further improvement by forming an integrated layer including
Was found to be effective. That is, the present invention
The upper layer 5A of the supporting film is
The lower layer 5B is hardly melted.
Of these different properties
The support film is integrally combined. support
The upper and lower layers 5A and 5B of the film are cured together.
The above effects can be achieved by using resin materials with different speeds
But also cured at room temperature to the supporting film
Use of isocyanate, etc.
The internal stress due to rugi does not remain in the support film
And the support film is hardened by curing
It is also possible to increase the size of the structure of the present invention.
It is a merit. The support film having such a structure is
The upper layer side and the lower layer side should not be completely the same composition.
Good. In other words, the upper layer has good adhesion to the protective film.
The lower layer side does not matter whether the above adhesive property is good or not.
Have good adhesion to the upper layer and have a large resistance to breaking force.
It is preferable to use a material exhibiting resistance. For that, the basic ingredients
With isocyanates in thermoplastic copolymers as
Active groups on the upper layer of the support film
More on the side to reduce the progress or degree of curing on the upper layer side
What should I do? To adjust the speed of curing,
Constructs the copolymer that is the upper layer material in the support film
For each monomer component, such as methyl metaacrylate
G, ethyl methacrylate, butyl methacrylate
And the like.
The amount of monomers such as tyl methacrylate is adjusted
It is preferable that the material of the lower layer be larger than the material of the upper layer.
No. Another method is to use polyiso-
A catalyst that promotes the reaction of cyanate may be used.
Alternatively, a polyisocyanate having a fast reaction may be used.
Capsule structure for retroreflective sheet of the present invention and glass vial
When manufacturing a retroreflective sheeting using
The first way to configure Lum as described above is
For example, the material film to be the upper layer in the support film
For example, on the surface of the almost hemispherical part of the metal-deposited glass beads
Pressed to completely bury the hemisphere portion of the beads
May be laminated with a lower film. Also, upper layer film
And the lower film are laminated in advance, and this is
Pressing against the beads is allowed. The above manufacturing method
The upper layer of the support film is
Enough to completely bury the hemispherical part with the coating
Thickness, the lower layer side shall be sufficiently thinner than the upper layer side
This is very important. In each case, the support
On a base polymer film that does not strongly adhere to it.
Applied with or without intervening release agent layer
It is convenient to use On the support film described above
The layer side and the lower layer side have a laminated structure that can be completely separated.
If you focus only on the polymer component,
It is easy to understand that it can be indistinguishable.
Let's go. The protective film is made of polymethyl
Not a homopolymer of acrylate or polycarbonate
Better. Those films ever believed
Reflection sheet having a structure according to the present invention
Is not suitable as a protective film material. Ma
Unlike traditionally believed, these materials
That the film consisting of
It is not preferable as a protective film for the reflection sheet. Biaxial
Stretched and oriented homopolymer films are relatively
When exposed to high temperatures, it consists of a portion of the support film.
Separation from the connected wall or cohesive failure in the connected wall.
Easy to occur. As described above, it is used in the present invention.
As a protective film, it is suitable for biaxial stretching
A more oriented polymethyl methacrylate film is also used.
Acrylic copolymer, if possible, or
In addition, for example, synthetic rubber, cellulose acetate
And / or copolymers such as styrene.
A homopolymer of polymethyl methacrylate
-It is expected that it is tougher and more stretchable than
I will. In addition, the support film is not
Good adhesion is not enough, especially with supporting film.
To create a sealed small compartment between the protective film
Do not cause internal destruction at the linear connecting wall
We need to take care of it. Contains no photosensitive monomer
Including monomers by using a suitable support film material
It is less susceptible to deterioration due to light than
Retroreflection with less intensity reduction due to temperature change and moisture absorption
A sheet capsule structure can be made. Glass bead
For manufacturing capsule-type retroreflective sheeting
When the glass beads are in the hemisphere surface and the space between the beads,
Metal deposition on the exposed support film surface without gaps
In a reflective sheet covered with a film, the support film
A thin line linking the protective film by heat molding
When providing a connecting wall, a considerable number of
In addition to metal-deposited glass beads or the surface of a support film
The metal film released from the mixture will be mixed. Such a difference
If an object is in the connecting wall, the temperature change applied to the reflective sheet
And internal strain due to moisture absorption weaken the inside of the fine line wall
It's easy to do. The characteristic of the reflection sheet according to the method of the present invention is that
Film surface in the gap between rotating glass beads
Has no metallized film and supports and protects
To form the support film so that the film is fused.
A free metal film exists in the connecting wall formed by
As a result, the above problem has been solved. Moth
Metallized film on the surface of the support film 5 between the lath beads
In order not to leave a
In the method, the beads are first supported on a temporary support
After passing through the process, the adhesive strength to the temporary support and the deposited film
Positive and relatively poor adhesion to the support film
After applying the lima in a thin layer, the support film is applied,
Next, the temporary support and the polymer layer adhered to it are integrated.
For example, a method such as selective peeling can be used. Cost
The temporary support and the metal deposition film on it and the support film
What is necessary is just to use the method which does not contact directly. EXAMPLES In order to contribute to a better understanding of the present invention, the present invention
Using glass beads as a light-reflecting element with a capsule-type structure
Example when applied to the manufacture of a retroreflective sheet
Then, it is as follows. Example 1 In Example 1, the upper layer side 5A of the support film 5 was made of a linear polyurethane.
The urethane composition, the lower layer side 5B as an acrylic composition,
Use both layers cross-linked and cured with polyisocyanate
And unstretched vinyl chloride as the main protective film
(Mitsubishi Plastics “Hishilex”)
This is an example. The thickness of the protective film 1 is about 80 μ, glass
Bead 2 has a refractive index of 1.92 and a diameter of 50 to 60 μm.
140g / m ² It is scattered. Hemisphere part of glass beads
The metal deposition film 4 on the surface is formed by vacuum-depositing metal aluminum.
A vapor-deposited film is formed on the surface of the support film 5.
No. Each set of the upper layer 5A and the lower layer 5B of the support film 5
The composition is as described below, and the upper layer has a thickness of about 80.
μ, the thickness of the lower layer is about 30 μ. Make this reflective sheet
The method is generally the same as the above-described method for producing a known reflection sheet.
The description is omitted to avoid duplication because they are the same, but the following points are added.
Add it. So that part of it is buried on the temporary support
Sprayed, the upper hemisphere part was covered with a metal deposition film
On the glass beads, place the support
The metal film on the temporary support and the supporting film.
Press the glass bead so that it does not touch
Embedded in the supporting film
And then remain on the temporary support and the temporary support
The metal deposition film is peeled off integrally. The above supporting film (FIG. 4)
5) as a release agent on the heat-resistant film 8
On top of the layer provided, methyl methacrylate 21
%, Ethyl acrylate 65% and 2-hydroxyethyl
Methacrylate 14% acrylic monomer
Polymerized in a mixed solvent of ene and methyl isobutyl ketone
Acrylic set adjusted to be 40% solid solution
100 parts by weight of the product, polyisocyanate (by
"Desmodur N-"
75 ") Lower side 5 of support film 5 consisting of 14 parts by weight
The material to be B is applied, followed by 70 ° C for 2 minutes followed by 90 ° C2
After a drying step for a minute, a 35% solids solution is
Linear polyurethane adjusted with ethyl acetate solvent
Composition (“N-3022” manufactured by Nippon Polyurethane) 10
0 parts by weight, polyisocyanate (Nippon Polyurethane Co., Ltd.)
"Coronate EH") 1.5 parts by weight and rutile type
Upper layer of support film 5 consisting of 20 parts by weight of titanium oxide
The material to be on the side 5A is applied, followed by 3 minutes at 60 ° C. 9
What passed through a drying process at 0 ° C. for 3 minutes can be used.
You. The heat-resistant film 8 is made of a saturated polyester film of about 15 μm.
It is film. The connecting wall 6 is heated at 170 ° C. by a known method.
It is formed by press molding. The connecting wall continuous in a line
Is as shown in FIG. More suitable
Although an example is shown, the present invention is limited to the above-described embodiment.
There is no. The support film 5 is made of a curable polymer material
Have a mutual degree of cure and therefore strength, elongation, protection
Have different adhesive properties to the
At least it is an integral thing including the upper layer side and the lower layer side,
In particular, the upper layer is a cushion that supports the adhesive and beads.
The lower layer is strong enough to withstand the destruction of the connecting wall.
Good to be. Of the reflective sheet according to the method of the present invention.
According to the structure, the protective film is limited to unstretched film
Instead, it may be a biaxially stretched film. Delay
When using stretched film, increase the strength of the connecting wall
If necessary, unstretched protective film on the lower layer side of the support film
Should be stronger than when using
No. Room temperature curing type polymer material, separately from supporting film material
It does not need to be. The physical properties of the upper and lower layers
It should be different. Another thin layer intervenes between upper and lower layers
May be. By the way, the main points that have been described so far
In summary, part of the support film is protected as a connecting wall
The conventional capsule-type reflective sheet adhered to the film,
Resistance to destruction or peeling of connecting walls under high temperature and humidity
Inferior in power. One possible way to improve this is consolidated
Due to the strengthening of the wall and the external structure,
And the destructive force is reduced.
Enhancement of interfacial adhesion between film and connecting wall and connecting wall itself
Of cohesive strength. Conventionally, protection film
It is considered that the strength is sufficient and there is no problem with the cohesion of the connecting wall.
Instead, attention was paid to enhancing the interfacial adhesion. Only
However, the above idea did not always apply. Interface
It is necessary to strengthen the connecting wall itself rather than strengthening the adhesion.
Sheet failure can often be caused by cohesive failure of connecting walls
It was confirmed. In addition, the protection which strengthened by biaxial stretching
The film makes it easy to break the sheet and uses it
May be appropriate, but optimal in relation to the conventional support film structure
It was also confirmed that it was not. Therefore, the solution is connected
Reinforcement of the wall itself, preferably substantially stretched
There is no protective film to use. Connecting wall is support
Required for the support film because it consists of a part of the film
Equipped with both cushioning property and strength required for connecting wall
This must be achieved with one film of one composition.
This support film is not always easy
The structure of the upper layer and the lower layer differ in composition and physical properties.
The latter is formulated with good adhesion to the protective film, the latter is strong
Dramatic improvement can be achieved by using a composition suitable for maintaining
It becomes possible. Curable resin material to strengthen the support film
Adhesive with protective film and glass beads
Room temperature curing in order to improve
Advantageously, a socyanate-based component is used. Above implementation
The advantages of the example are clear from the above. The capsule structure for a retroreflective sheet according to the present invention.
The body is composed of at least the upper layer side and lower layer side
And a structure consisting of parts with different physical properties
Connection due to deterioration due to artificial force or aging
Integrated against interfacial or cohesive failure of wall
Exhibits strong resistance and significantly prevents shrinkage deformation due to heating
can do. The capsule for a reflection sheet according to the present invention
The structure has good bonding between the protective film and the support film
Even under high temperatures such as extremely hot places, both films
Shows a strong resistance to the separation of For example, at 145 ° C
When left for 1 to 2 minutes at the temperature, the conventional reflection sheet
Of the protective film shrinks and peels and hardly retains its original shape
The capsule structure of the present invention
No change is observed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic longitudinal sectional view of a conventional ordinary reflection sheet. FIG. 2 is a schematic longitudinal sectional view of a known capsule-type reflection sheet. FIG. 3 is a schematic view of a surface of the reflection sheet of FIG. 2; FIG. 4 is a partially enlarged view of an embodiment in which the capsule-type structure for a retroreflective sheet of the present invention is applied to the structure of a retroreflective sheet using glass beads as a reflective element. FIG. 5 is a diagram showing an example of a surface pattern of the reflection sheet of the embodiment shown in FIG. 4 by a connecting wall. DESCRIPTION OF SYMBOLS 1 Transparent protective film 2 Glass beads 3 Transparent reflective film layer 4 Metallized film 4 ′ Metallized film 5 on film 5 Supporting film 5A Supporting film upper layer side 5B Supporting film lower layer side 6 Fine connecting wall 7 Sealing Small compartment vacancy 8 Heat resistant film

Claims (1)

(57) [Claims] The protective film and the supporting film are partially connected by a connecting wall formed by melt-molding the supporting film, and the inside surrounded by the connecting wall 6 is a sealed independent closed capsule-shaped small compartment. Wherein the support film has a laminated structure of at least two layers of an upper layer and a lower layer, and the upper film and the upper layer. The lower layer has a composition and properties different from those of the lower layer, and the upper layer has a composition having good adhesion to the protective film when the connection wall is formed by the above-mentioned melt molding. Wherein the layer has a composition having good adhesion to an upper layer and exhibiting greater resistance to breaking force. 2. The polymer composition forming the upper layer of the support film has a smaller content of the active group that reacts with a crosslinkable component such as isocyanate than the polymer composition forming the lower layer thereof. 2. A capsule-type structure for a retroreflective sheet according to claim 1.