JPS5915068B2 - Method for manufacturing high brightness partially reflective fabric - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a highly bright partially reflective fabric in which glass beads are embedded.In general, partially reflective fabrics are produced by forming a resin interface on the front hemisphere of the glass beads, and forming a resin and a glass bead. A focal length adjusting resin layer is provided between the rear hemispherical surface of the glass beads and the light reflecting layer due to the mutual refractive index of the glass beads.

This retroreflective structure is formed by a gravure roll cut into a desired shape and bonded to a fibrous material, or engraved into a desired shape. For example, in the case of the former method, apart from making continuous production particularly difficult, it also prevents products with high retroreflectivity from being obtained. In such a partially reflective fabric, if the front hemisphere of the glass beads is an air interface with a refractive index of approximately 1, use glass beads with a refractive index of 1.9 to 2.0, and By providing a light reflective layer along the spherical surface, a high degree of light retroreflection can be obtained.

However, with this fabric, water does not adhere to the front hemisphere of the glass beads.
As a result, the refractive index of the glass beads apparently decreases, the reflective performance of the reflective layer decreases, and the optical retroreflectivity is lost. Therefore, when the front hemispherical surface of the glass beads is used as an air interface, it is necessary to cover them with a transparent protective film as shown in Japanese Patent Publication No. 40-7870, for example. The present invention thus provides an improved method for manufacturing a highly bright partially reflective fabric in which the front hemispherical surface of the glass bead is used as an air interface and is covered with a transparent protective film. That is, in this invention, the polyethylene layer of polyethylene laminated kraft paper is selectively melted using one of the engraving rolls, glass beads are scattered and temporarily planted, aluminum is vacuum-deposited, and then a thermoplastic resin base sheet is attached to the polyethylene layer. The glass beads are transferred to the convex surface of the base sheet by selectively heating with one of the engraving rolls. After planting, the polyethylene laminated kraft paper is peeled off, and then a transparent protective film is applied to the bead-exposed side of the base sheet. With the other engraving roll facing the base sheet, darken it in the bead transfer area, leave a gap, make it protrude in the remaining area, and fuse it to the film■0
A method for producing a highly luminous partially reflective fabric. Examples of the present invention will be described below. Fig. 1 is a plan view of a highly bright partially reflective fabric manufactured according to this example, Fig. 2 A to E are semi-finished products shown in the order of steps in this example, and Fig. 5 is a cross-sectional view of a finished product. It is. FIG. 1 shows a glass bead distribution area 1 below a transparent protective film 8 made of polyurethane.

Kraft paper 2 with a wet strength of 2 to 3 kg is dry-laminated with 30μ of medium-low density polyethylene 3 as shown in Figure 2A.
was engraved into a desired pattern in a convex manner and passed through one engraved roll heated to 120 to 140° C. with the polyethylene coated side facing outside.

At this time, about three times as much polyethylene as the engraved convex area of the roll is melted to form a sticky layer, and the glass beads 4 sprinkled from above have already been adhesively planted on the polyethylene 3 as shown in the figure. Glass beads 4 have a diameter of 40 to 80
Transparent grains with a refractive index of μ of 1690 to 1.93, which adhered to the polyethylene surface in an undesired thin area, were blown away with air. In order to increase the adhesion of the glass beads, the glass beads were heated for an additional 2 minutes at 120 to 140° C. after the beads were dispersed. Glass beads are about 20% of the diameter
is embedded, and as shown in the figure, aluminum 5 is vacuum deposited on this exposed surface to form a reflective layer. Although the glass beads have approximately ↓ of their diameter exposed, due to the straightness of evaporation, aluminum is evaporated only to approximately ↓ of their diameter. A thermoplastic resin base sheet 6 is butted against the bead temporary planting surface with the support film of this sheet on the back side, heated to 150°C using one engraving roll 7 on the shinito side, and a rubber roll 10 on the kraft paper side. The rolls are then placed at room temperature and laminated between both rolls. This state is shown in FIG. 2A, where the base sheet 6 is lifted up onto the convex surface of the engraving roll, and glass beads are transferred and implanted onto the convex surface on the side to which the aluminum is adhered. The base sheet used here is made, for example, as follows. That is, a non-yellowing one-component polyurethane (for example, HA-6 manufactured by Hani Kasei Co., Ltd.
80), 0.5 parts of a silicone leveling agent (for example, Toray SH-8400), 25 parts of MEK, and 25 parts of DMF to a coating weight of 50μ after drying, and dried in air at 100°C. It is something. In order to cover the transparent protective film with the same material as this base sheet, prepare an amount twice the area of the product. Once the glass beads have been transfer-embedded onto a polyurethane base sheet, in this example polyurethane, and cooled, the polyethylene laminated kraft paper 23 is then peeled off.

At this time, even if there are glass beads left on the polyethylene surface other than at desired locations, these beads are removed and are not transferred to the base sheet. The opening in Figure 2 shows this state. A transparent protective film 8 made of the same material as the sheet is attached to the bead-exposed surface side of the base sheet 6 on which glass beads are implanted, with the support film on the back side, so as to correspond to the convex or concave surface of one of the engraving rolls mentioned above. The other engraving roll 9, which has an inverted concave or convex shape, is used on the base sheet side.
Heat to 5'C, using metal roll 11 on the protective film side, heat to 100'C, and bond the polyurethane side of both the base sheet and the protective film between both rolls.

FIGS. 2C, 2, and 2E schematically show the shape of the base sheet that changes instantaneously under the roll. The other engraving roll heats with its convex surface and therefore has no heating effect on the glass beads. After cooling, the support film of the sheet and film, that is, the polyethylene terephthalate film, is peeled off and the resulting high brightness partially reflective fabric is further processed if necessary for use. In the figure, beads are distributed between 6' and 85 where the base sheet and the transparent protective film are each separated from the back support film, and the fiber cloth 12 is pasted on the back side of the base sheet. Showing the product. In addition to urethane resin, other resins such as acrylic and alkyd may be used for the base sheet and protective film.

The high brightness partially reflective fabric thus formed has an air interface formed between the front surface of the glass beads implanted in the base sheet and the protective film, and the observation angle is 0.
The front brightness is 250 according to JIS standard Z-9117 at a human angle of incidence of -4.

On the other hand, when the front spherical surface of the glass bead is the resin interface, it is only 70. Therefore, the partially retroreflective area is 3 mm.
In the case of x377!11 spacing of 5CfL, it can be confirmed from 100m in front, and the amount of glass beads used is extremely small, making it possible to obtain inexpensive, lightweight, and easily visible products with easy process control.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a highly bright partially reflective fabric obtained by the method of the embodiment of the present invention, FIGS. be. 23 in each figure...polyethylene laminated kraft paper,
3... Polyethylene layer, 4... Glass beads, 5...
... Aluminum, 6ζ... Thermoplastic resin base sheet, 8'-- Transparent protective film, 7... One engraving roll, 9... Other engraving roll.

Claims (1)

[Claims] 1. After selectively melting the polyethylene layer of the polyethylene laminated kraft paper using one of the engraving rolls and scattering glass beads, aluminum was vacuum-deposited,
Next, the thermoplastic resin base stickers are placed in contact with each other and selectively heated using one of the engraving rolls to transfer and implant the glass beads on the convex surface of the base sheet, and then the polyethylene laminated kraft paper is peeled off. High-luminance partial reflection characterized by placing a transparent protective film facing the exposed side and using the other engraving roll to indent the base sheet in the bead transfer area to leave a gap and protrude in the remaining area and fuse it to the film. Method of manufacturing sex fabric.