JP2000205790A - Transparent face shield - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lightweight transparent shield for protecting face in which excellent elasticity resistance and fitting feeling can be ensured by employing a fiber reinforced composite having specified single yarn strength at a part or a main part of the shield. SOLUTION: A transparent face shield comprises a transparent material 1 and a high strength fiber reinforced composite 2. A visual field part 3 is ensured in the transparent material 1. Single substance of polymethyl methacrylate, polycarbonate, polypropylene, or the like, or a multiplayer body combining them is employed as the transparent material 1. Area ratio of the high strength fiber reinforced composite to the transparent material is set at 30% or above and polyaramide fiber, ultrahigh molecular weight polyethylene fiber, polyparaphenylene benzbisoxasol fiber, or the like, is employed as the high strength fiber. The high strength fiber reinforced composite is obtained by forming these fibers temporarily into cloth shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent face shield which is light in weight and excellent in wearing feeling.

[0002]

2. Description of the Related Art As a transparent face shield for protecting the front face of a conventional bulletproof helmet, a substantially rectangular shape which is mainly made of polycarbonate resin and is uniaxially curved has been used. The transparent face shield is mounted by extending a metal arm from the side of the cap body so that they can be opened and closed upward, so that they can be lowered only when necessary to protect the face.

[0003]

However, although polycarbonate is excellent in impact among transparent engineering plastics, it requires a thickness of as much as 30 mm in order to prevent, for example, Tokarev bullets. Yes,
There is a problem that the weight becomes heavy. Furthermore, because of the mounting structure, since the transparent face shield is located in front of the face, torque is applied, so that the transparent face shield feels heavier than expected. Especially when lifting the transparent face shield upward,
Even a slight movement of the head caused a feeling of flutter due to its own weight, and even in emergency situations, it was even dangerous.

[0004] In view of the background of the prior art, the present invention provides
An object of the present invention is to provide a transparent face shield which is lightweight, maintains elasticity, and is excellent in a feeling of wearing.

[0005]

The present invention employs the following means to solve the above-mentioned problems. That is, in the transparent face shield of the present invention, in a transparent face shield for protecting the face, a part or a main part of the transparent face shield contains a composite containing a fiber having a single yarn strength of 10 g / d or more as a reinforcing material. It is characterized by having.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has been made as to the above-mentioned problem, that is, a transparent face shield which maintains the elasticity and is excellent in a feeling of wearing despite being light in weight has been intensively studied. Regarding the amount of a certain polycarbonate resin used, as a practical matter, it becomes thick in order to obtain the required elasticity resistance, and as a result, it becomes heavy, so that the transparent material is kept to a minimum necessary to secure a visual field, etc. Although the part is not transparent, when I tried to construct a composite with high strength fiber with the same elastic resistance but light weight as a reinforcing thread, surprisingly, it was possible to realize a light weight while securing the field of view as a whole, It has been sought to solve such a problem at once.

Next, the structure of the present invention will be described below with reference to the drawings. FIG. 1 is an overall view of a transparent face shield according to the present invention, which is composed of a transparent material 1 and a high-strength fiber-reinforced composite 2. 3 in the transparent material is a portion secured as a visual field. On the other hand, the conventional product is entirely made of a transparent material as shown in FIG. FIG. 3 is an example showing various ways of attaching the transparent material 1 and the high-strength fiber-reinforced composite 2. FIG. 4 is an example showing a state where the transparent face shield of the present invention is attached to a cap body.

In the present invention, the purpose of using the reinforced composite is to obtain resistance to resilience from a handgun, and in order to obtain resistance to elasticity using a conventional transparent material, it must be made extremely thick. As a means for reducing this, a high-strength fiber-reinforced composite which is thin but has high ballistic resistance is used in portions other than the viewing area.

The shape of the transparent material 2 may be a flat plate, but is preferably a curved body having a uniaxial curvature or a multiaxial curved body conforming to the shape of a human face.

FIG. 3 shows how to include the transparent material 2 and the reinforcing composite, that is, the mounting shape.
A mechanical attachment method as shown in A to D, or
A method of embedding a reinforcing composite as shown in D and E in a transparent material can be adopted.

Examples of such transparent materials include polymethyl methacrylate, polycarbonate, polypropylene, polystyrene, unsaturated polyester, acrylonitrile.
Even a simple substance such as butadiene / styrene or polyethersulfone, a multilayer body of these simple substances, or a multilayer body combining two or more of them can be used. As the adhesive used for such lamination, an adhesive having excellent transparency, such as an epoxy-based, urethane-based, or polyvinylbutyral-based adhesive, can be used.

As a means for improving the elasticity of such a transparent material, for example, polycarbonate which is excellent in impact resistance can be adopted. However, even if such a transparent material is used, the bullet speed of a handgun bullet is 500 m. It has been empirically found that when the rate is about / s, the thickness of the material needs to be increased to about 40 mm. This thickness is considered to be extremely thick in the field, and a study of thinning is made in terms of various materials, and their compounding or bonding method. As a result, polymethyl methacrylate and polycarbonate At present, it has been found that it is extremely effective to combine and laminate and interpose an elastic adhesive having a thickness of about 2 mm at the interface between them.
In the case of the same elasticity resistance, the thickness of the material is 40
It has been found that it is possible to reduce the thickness from mm to 21 mm.

Conventionally, in a helmet, a high-strength fiber-reinforced composite has been used to form a portion other than a transparent material for securing a visual field. However, the purpose is to use such a high-strength fiber-reinforced composite. In other words, it goes without saying that the proportion of the material in the face shield is preferably as large as possible.

The area ratio of the high-strength fiber-reinforced composite to the transparent material is preferably at least 30%, more preferably at least 50%. However, on the other hand, there is a demand to increase the field of view, so that it is practically determined in consideration of whether to emphasize the field of view or weight reduction.

The shape of the face shield may be a flat plate as its basic function, like the transparent material, but a single-axis curved body or a multi-axis curved body is preferably effective in consideration of covering the human face. .

Further, in such a face shield, it is preferable that the portion below the eyes be formed in a semi-elliptical shape extending along the chin from the cheek of the face, rather than extending the width of the eyes. Is effective for

If the transparent material contains a high-strength fiber-reinforced composite, that is, if the shape to be attached is a butt shape, a gap is inevitably created mechanically, and the elasticity resistance is extremely reduced in a local area, causing the bullet to penetrate. Therefore, it is preferable that such a transparent material and the high-strength fiber-reinforced composite are slightly overlapped, attached, and contained. Furthermore, bonding with an adhesive at the overlapped portion is not recommended in terms of durability, even if it is good in the initial period. Rather, it is preferable to employ means for fixing with mechanical bolts and nuts in terms of strength. The shape of the bolts and nuts is preferably, for example, a dish with a rounded head, in order to prevent danger or to provide a sense of security in case of contact because the face shield is mounted near the face.

Examples of such high-strength fibers include polyaramid fibers, ultrahigh molecular weight polyethylene fibers, ultrahigh molecular weight polypropylene fibers, ultrahigh molecular weight polyvinyl alcohol fibers,
Polyparaphenylene benzobisoxazole fiber, polyarylate fiber, carbon fiber and the like can be used.
Among these, aramid fibers are preferably used, and as such aramid fibers, fibers composed of polyparaphenylene terephthalamide or a copolymer thereof, for example, copolyparaphenylene-3,4-oxydiphenylene terephthalamide may be used. it can.

As such high-strength fiber, a single yarn strength of 10
Those having g / d or more are used. That is, if the breaking strength of the fiber itself is less than 10 g / d, it is not possible to efficiently withstand the impact energy against the bullet, and it is not possible to exhibit sufficient elasticity resistance.

The high-strength fiber-reinforced composite referred to in the present invention is a material obtained by selecting these fibers from a cloth-like material, for example, a sheet-like material, a woven fabric, a knitted fabric, a three-dimensional woven fabric and a three-dimensional knitted fabric which are uniaxially aligned. It is configured to include at least one type. That is, it is obtained by woven into a woven fabric using such a cloth material, for example, the high-strength fiber, adhering 5 to 20 g% · owf of the matrix resin to the woven fabric, laminating a plurality of the woven fabrics, and thermocompression bonding. Alternatively, a sheet-like material in which the knitted fabric and the high-strength fiber are aligned in one direction is embedded in a thermoplastic resin, and a sheet once attached is formed, and the sheets are alternately stacked, and a plurality of sheets in an orthogonal stack are laminated. Obtained by thermocompression bonding.

Examples of the matrix resin include polyvinyl butyral, phenol, epoxy, polyethylene vinyl acrylate, polyvinyl acetate, polyvinyl chloride, polyacrylate, polyurethane, synthetic rubber, natural rubber, and mixtures of polyvinyl butyral, phenol and epoxy. Alternatively, mixtures thereof can be used.

[0022] The surface density of such high strength fiber-reinforced composite, preferably in the range of ^{5kg / m 2 ~15kg / m 2} . If it is less than 5 kg / m ² , it will be light in weight, but will not have sufficient elasticity resistance to achieve the desired performance. If it exceeds 15 kg / m ² ,
Although sufficient elasticity resistance can be obtained, it becomes too heavy and is not suitable for weight reduction, which is one of the objects of the present invention. Further, since the thickness becomes large, particularly at the joint between the transparent material and the high-strength fiber-reinforced composite, the thickness becomes extremely large, so that the operability is deteriorated, the commercial value is significantly impaired, and it is not appropriate. In addition, it is also possible to color the high-strength fiber composite in any color by dyeing or painting,
Of course, a free pattern such as a picture, a symbol mark, or a character can be drawn on the portion.

The face shield of the present invention may be used as a sports cap, a stone cap used by a police officer, or a flying cap used by a SDF member or a general security guard. And the like.

[0024]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 A transparent material was formed in a rectangular shape and the total area was 160 cm ² . The area of the visual field therein was set to 100 cm ² in consideration of the attachment portion between the transparent material and the high strength fiber composite.

As a structure of such a transparent material, a material having a thickness of 13 mm of polymethyl methacrylate from the landing side was bent so that the outer peripheral portion of the cap body flange and the inner peripheral portion of the polymethyl methacrylate were substantially in contact with each other.

Behind the polymethyl methacrylate, a polycarbonate 6 mm thick bent so as to be in close contact with the inner periphery thereof was disposed.

Both of these adhesives were carefully processed with a polyurethane-based adhesive while ensuring a thickness of 2 mm to prevent air bubbles from entering.

As a method of manufacturing a high-strength fiber-reinforced composite, aramid fiber (Kevlar 29 3000d manufactured by DuPont) was used as the high-strength fiber, and the warp direction woven density was 1%.
The woven fabric was woven with a plain weave structure of 7 lines / inch and a horizontal weave density of 17 lines / inch.

The woven fabric was passed through a roll coater to impregnate the binder. As the binder, a polyvinyl butyral-based resin and a solution concentration of 17% were used. The adhesion amount is 120
After drying at 20 ° C. for 20 minutes, the content was 10 g% owf.

A laminate of 20 woven fabrics was inserted into a heating press, and a high-strength fiber-reinforced composite was produced under the conditions of 165 ° C. × 100 kg / cm ² × 15 minutes. As shown in FIG. 1, the shape of the high-strength fiber-reinforced composite was such that the portion below the eye where the transparent material was attached was adapted to a curved shape extending from the cheek to the chin of a human face. The mounting method of this high-strength fiber reinforced composite is as follows: a bolt and a nut are used to make a 6 mmφ co-hole of polymethyl methacrylate and a high-strength fiber composite at four locations, two on each side when viewed from the front, and an M5 bolt・ Mounted with nuts. Bolt is truss bolt 40
mm was used. The nut used was a 17 mmφ flat nut.

The total weight of the face shield was 700 g for the face shield part. The weight of the transparent material as the main member was 420 g and the composite was 250 g. The bulletproof performance of this product was evaluated as follows.

As the evaluation device, Sumitomo Coal Mining's High
Using speed Flying Object Testing System HFT-105,
Smokeless gunpowder amount 25 so that the velocity at impact is 500 m / s
g.

As a simulated bullet, 5.4 g of a brass cylinder of 7.62 mmφ was inserted into a polyethylene sabo and placed 200 mm in front of a smokeless powder. Sabo was evaluated just before landing on the sample and detached so that only the bullet landed on the sample.

As a result, the central portion of the transparent material was also ballistic resistant with a margin at both the central portions of the high-strength fiber composite material.

In terms of operability, the face shield of the present invention was attached to a cap using a conventional mounting bracket, and the length of the face shield was shortened so that the face shield and the cap were substantially in contact with each other. Because of its light weight, there is no headache caused by pressure when worn for a long time as seen with conventional products, and you also feel the instability due to centrifugal force generated when you move the face shield up and down There was no.

Example 2 The structure of the transparent material was 2 mm thick polycarbonate from the landing side.
Polymethyl methacrylate 10mm thick, adhesive layer 2mm
A face shield was prepared in the same manner as in Example 1 except that the thickness was 6 mm and the total thickness was 17 mm. The evaluation results of this face shield were the same as those of Example 1 in terms of elasticity resistance and operability.

Comparative Example 1 The entire face shield was made of a transparent material without using a high-strength fiber-reinforced composite. The content of the composition is 10 mm thick polymethyl methacrylate from the landing side, adhesive layer 2
mm thickness, polycarbonate 5 mm thickness and total thickness 17 mm. The total area was 500 cm ² . Example 1 The mounting position of the face shield was set at a position 30 mm away from the cap body.
A face shield was created in the same manner as.

As a result of evaluation of this face shield, three out of ten shots penetrated the ballistic resistance. Regarding the operability, when the face shield was raised and lowered, the centrifugal force was large and the head felt swaying, and together with the torque, the front part of the cap body slipped downward, and the wearing feeling was extremely poor. In addition, even with a long cap coming from the weight, I felt even a headache due to the feeling of pressure.

[0040]

According to the present invention, the screen shield, which has been a major problem with the conventional product, is too heavy, and the centrifugal force generated when the face shield is moved up and down causes a feeling of wobble and a slip toward the front of the cap. Can eliminate problems such as heavy feeling, and can provide an excellent face shield free from problems such as a reduction in the protection area and a reduction in the visual field.

[Brief description of the drawings]

FIG. 1 is an overall view of a transparent face shield of the present invention.

FIG. 2 is an overall view of a conventional transparent face shield.

FIG. 3 is a schematic view showing how to attach the transparent material of the present invention to a high-strength fiber-reinforced composite.

FIG. 4 is a schematic view showing a state in which the transparent face shield of the present invention is attached to a cap.

[Explanation of symbols]

 1, 4: transparent material 2: high-strength fiber-reinforced composite 3: part of transparent material for viewing 5: cap

Claims (13)

[Claims] 1. A transparent face shield for protecting a face, characterized in that a part or a main part of the transparent face shield contains a composite containing a fiber having a single yarn strength of 10 g / d or more as a reinforcing material. Transparent face shield. 2. The transparent face shield according to claim 1, wherein the shape of the opening serving as the field of view of the face shield is at least one selected from a polygon and a circle. 3. The composite as claimed in claim 1, wherein the composite comprises at least one selected from the group consisting of polyaramid fibers, ultrahigh molecular weight polyethylene fibers and polyparaphenylene benzobisoxazole fibers.
4. The transparent face shield according to any one of 3. 4. The composite according to claim 1, wherein the composite is formed of a sheet-like material, a woven fabric, a knitted fabric, a three-dimensional woven fabric, and a three-dimensional knitted fabric which are aligned in a uniaxial direction. The transparent face shield according to any one of claims 1 to 4, characterized in that: 5. The transparent face shield according to claim 4, wherein a plurality of said cloth-like materials are laminated. 6. The transparent face shield according to claim 1, wherein said composite comprises a thermoplastic resin or a thermosetting resin as a matrix resin. 7. The transparent face shield has a surface transmissive area of 7
The transparent face shield according to any one of claims 1 to 6, wherein the transparent face shield has a size of 00 cm ² or less. 8. The composite according to claim 1, wherein a surface area ratio of said composite to a transparent material is 30% or more.
The transparent face shield according to any one of the above. 9. The transparent face shield according to claim 1, wherein an inner curved surface of the transparent face shield is attached so as to substantially contact an outer curved surface of the helmet. 10. The transparent face shield according to any one of claims 1 to 9, wherein the transparent face shield has a ballistic resistance of a transparent material equal to or higher than the NIJ standard level II. 11. The transparent face shield according to claim 1, wherein the composite material has a ballistic resistance of at least NIJ standard level II. 12. The transparent face shield according to claim 1, wherein the transparent face shield has a cap. 13. The transparent face shield according to claim 12, wherein said transparent face shield is fixed to a lower part of an eave of said cap body.