WO2022197256A1

WO2022197256A1 - Work and safety boot comprising two distinct layers

Info

Publication number: WO2022197256A1
Application number: PCT/TR2021/050226
Authority: WO
Inventors: Rifat YESILTEPE
Original assignee: Pollyboot Cizme Sanayi Ve Ticaret Anonim Sirketi
Priority date: 2021-03-15
Filing date: 2021-03-15
Publication date: 2022-09-22

Abstract

Subject of the invention is related to a work and safety boot (1) with enhanced structural properties in order to increase occupational safety of workers. The invention in question is related to a work and safety boot (1) with enhanced insulation properties which will not let the user feel cold or sweat under harsh weather conditions and which will not make the user feel tired due to its lightweight structure.

Description

WORK AND SAFETY BOOT COMPRISING TWO DISTINCT LAYERS

Technical Field

Subject of the invention is related to a work and safety boot with enhanced structural properties in order to increase occupational safety of workers. The invention in question is related to a work and safety boot with enhanced insulation properties which will not let the user feel cold or sweat under harsh weather conditions and which will not make the user feel tired due to its lightweight structure. Technical Background

Today, the boots used for occupational safety purposes include thermally- insulated boots made of full rubber material, full polyvinyl chloride (PVC) material, full polyurethane (PU) material, full ethylene vinyl acetate (EVA) material or polyurethane and thermoplastic polyurethane (PU/TPU) composite. Being equipment utilised by the users for a full work day, ergonomic structure and practicality of use are very important for work and safety boots. Therefore, removable pile socks with good thermal isolation properties are added into the boots developed to provide comfort and adapt to harsh weather conditions. Due to their lack of practicality in use, pile socks are not generally preferred by users. In addition, safety boots fully made of rubber material tire the user very much due to their greater weight. Due to the reasons detailed above, structural properties of work and safety boots in the current state or the art are found lacking. Thus, due to user complaints, the need arises to use lighter materials at upper parts of the boots with heavy construction and studies to develop the structural properties of boots continue.

Cold isolation level of work safety boots is measured at the sole as a standard and compliance with relevant specifications is determined according to this test method. Heat isolation specifications by EN ISO 20347 and EN ISO 20345 and measurements used to determine figures according to these specifications are only conducted at the sole area of the boots. Today, the required conditions of these specifications are met by increasing the sole thickness of work safety boots. However, in reality the users prefer boots which have thick upper parts and good heat isolation as well as thick soles in order to avoid feeling cold in harsh weather conditions. However, boots which have both thick soles and thick upper sections are very heavy and thus are not very practical to use. In addition, lacking breathability, these boots also make user's feet sweat. Work and safety boots bearing the abovementioned properties in the current state of the art;

- Allow the user's feet to feel cold due to lacking heat isolation in the boots;

- Tire the user due to heavy boot weight;

- Allow the user's feet to become sweaty due to the lack of air circulation in the boots; and

- Fail to provide sufficient performance for the user due to lack of practicality in use of the boots.

In addition to use of pile socks, an alternative design referred to as rigger boot in the literature has mouflon lining sewn or adhered into the boots for heat isolation in the current state of the art. Later addition of lining by sewing or adhesives onto the previously completed boots can cause problems in use. In addition, post-production sewing or adhesive interventions can also cause wastage of inner isolation material and increases in boot costs due to potential production errors.

Purpose of the Invention The main purpose of the invention subject is to provide a work and safety boot with enhanced insulation properties which will not let the user feel cold or sweat under harsh weather conditions and which will not make the user feel tired due to its lightweight structure, in order to enhance ergonomic structure and practicality of use of work and safety boots which are utilised by the user for the entire work day.

Another purpose of the invention subject is to produce boots from a material which is lighter than those utilised in current state of the art in order to provide a work and safety boot which will not tire the user and provide maximum performance.

Another purpose of the invention is to prevent wastage of inner layer by the method of attachment of inner layer and outer layer forming the safety boots at the injection points in later stages of production and allow the inner layer to be reused.

Thus the invention;

- Ensures the user's feet do not feel cold due to enhanced heat isolation in the boot;

- Ensures the user is not tired due to production of the boots from a lighter material;

- Ensures the user's feet do not get sweaty due to provision of air circulation in the boots; and

- Ensures maximum performance for the user due to easier and more practical usability of the boots.

Detailed Description of the Invention

The images related to the double layered work and safety boot subject to this invention are as follows:

Image-1: View of a single injection and (single) polyurethane consistency boot

Image-2: View of a double injection and (double) polyurethane consistency boot

Image-3: View of a boot with two materials and two consistencies Reference Numbers:

1. Safety Boot

2. Inner Layer

3. Outer Layer

4. Air Gap

5. Polyurethane Leg

6. Vulcanised Rubber Sole 7. Injection Point

8. Injection Area

9. Sole Injection Area

10. Polyurethane Lower Area

11. Polyurethane Upper Area

12. Rubber Sole

13. Bridge

A safety boot (1) produced in accord with Work and Safety Boot Standards (EN ISO 20347 and EN ISO 20345) is shown in Image-1. The safety boot (1) shown in Image-1 is comprised of five distinct elements including the inner layer (2), the outer layer (3), the air gap (4), the polyurethane leg (5) and the vulcanised rubber sole (6).

In the safety boot (1) the part contacting the user's foot is called as the inner layer (2). The inner layer (2) is comprised on a foam material with air mesh properties, made from a combination of certain chemical materials in certain ratios in order to provide ergonomic use and comfort for the user during work. The chemical materials which can be used for the inner layer (2) include ethylene vinyl acetate (EVA), polyurethane foam (PU) and/or rubber foams combined in certain chemical rations. Combination of the chemical materials brought together to form the foam inner layer (2) are not limited to a fixed ratio and can be produced in the desired ratio, the desired hardness and the desires thickness according to required comfort and environmental conditions. Inner layer (2) thickness varies from 1 to 8 mm. The foam material produced for the inner layer (2), for example, can be formed of combinations of 50% chloroprene and 50% styrene butadiene rubber (SBR), ethylene propylene diene monomer (EPDEM), or polypropylene (PP) rubber. In safety boots (1) where breathability is important, evaporation of condensed sweat occurring after some time following sweating will gather the heat for this reaction from the user's feet, thus making the user's feet cold. Building the inner layer (2) out of foam material also prevents sweating during use. Thus, high levels of breathability and air circulation are provided in the safety boot (1) and sweating of the user's feet is prevented.

Image-1 shows the outer layer (3) forming the outside surface of the safety boot (1). The outer layer (3) fabric must have level 3 wear resistance, shear resistance and puncture resistance according to EN 388:2016 as a minimum. The outer layer (3) fabric can be an ultra-high molecular weight polyethylene (UHMWPE) and/or an ultra-high performance, shear-resistant fabric made of an innovative combination of fibres in special high density weaving machines in the current state of the art according to the EN 388:2016 standard. Alternatively, the outer layer (3) can also be made of durable materials like spandex, nylon, canvas, wool or polyester. The outer layer (3) can be produced in the desired design including one or more colours. The outer layer (3) is produced in a lesser thickness in comparison to the inner layer (2) for user comfort. While the inner layer (2) thickness ranges from 1 to 8 mm, the outer layer (3) thickness ranges from 0.3 to 1.0 mm. The outer layer (3) provides comfort for the user's feet with its water-proof and air permeable properties. The inner layer (2) and outer layer (3) forming the safety boot (1) are made lighter thanks to the properties detailed above. This way, insulation properties of the safety boot (1) are enhanced by use of light materials, providing a safety boot (1) which does not make the user's feet sweat and which provides more practical use.

Image-1, Image-2 and Image-3 show the inner layer (2) and the outer layer (3) forming the safety boot (1). In order to produce the safety boot (1) first the inner layer (2) is placed on the core as the first layer. The outer layer (3) is placed as second layer on the inner layer (2) placed on the core. The outer layer (3) is sewn like a sock before this step in order to be able to pull the outer layer (3) on the core. When sewing the outer layer (3) as a sock some points can be sewn looser according to preference of the producer. These loosely sewn points on the outer layer (3) form the injection points (7). The outer layer (3) sewn as a sock is pulled over the inner layer (2) previously pulled onto the core. In order to form the safety boot (1) the inner layer (2) and the outer layer (3) pulled onto the core one atop the other must be attached to each other. To this end, a polyurethane material is injected through the injection points (7) formed on the outer layer (3). When the polyurethane material is injected, it diffuses from the injection points (7) and moves towards the inner layer (2). When the diffused polyurethane material cures, this forms bridges (13) between the inner layer (2) and the outer layer (3). This way, the polyurethane material injected into the injection points (7) forms bridges (13) between the inner layer (2) and the outer layer (3) to attach them to each other. Forming bridges (13) only at a limited number of points prevent the inner layer (2) and the outer layer (3) from coming into full contact with each other. This way, the injection points (7) being located only on a limited number of points on the safety boot (1) creates an air gap (4) between the inner layer (2) and the outer layer (3). The air gap (4) between the inner layer (2) and the outer layer (3) provides high level heat isolation. Providing great benefits in terms of air circulation, this air gap (4) ensures the user's feet are kept warm without causing them to sweat. The air gap (4) on the safety boot (1) enhances heat isolation and provides high level air transfer. (Image-1) The non-slip polyurethane leg (5) and vulcanised rubber sole (6) form the lower part of the safety boot (1). The polyurethane leg (5) and the vulcanised rubber sole (6) are combined at the shocking units of the injection machines. Combination of the polyurethane leg (5) and the vulcanised rubber sole (6) is achieved by injection of polyurethane material into the injection area (8) on the safety boot (1). This way, the polyurethane leg (5) is positioned at the outmost position to take place at the leg section of the safety boot (1) and thus stays as a layer separate from the vulcanised rubber sole (6). (Image-1)

The polyurethane leg (5) seen in Image-1 is positioned on the leg section of the safety boot (1). A single type of polyurethane leg (5) material is injected in the same density for both the sole and the leg areas of the safety boot (1) polyurethane leg (5). Image-2 shows an alternative application of the polyurethane leg (5). Unlike the polyurethane leg (5) seen in Image-1, the example in Image-2 is comprised of two separate areas with differing densities, namely the lower area (10) and the upper area (11). The polyurethane upper area (11) reaches up to leg area on the safety boot (1) and it is formed by injection of the polyurethane material into the injection area (8). On the other hand the polyurethane lower area (10) forms the sole section of the safety boot (1) by injection of polyurethane material into the sole injection area (9). This way, the polyurethane upper area is made to have lower density in comparison to the polyurethane lower area (10). (Image-2)

The polyurethane leg (5) is positioned at the outermost section at the leg area of the safety boot (1) and stays as a layer separate from the vulcanised rubber sole (6). (Image-1) Vulcanised rubber sole (6) forming the sole area of the safety boot (1) is shown in Image-1 and Image-2. The vulcanised rubber sole (6) seen in Image-2 is produced as a solid structure which also encapsulates the polyurethane lower area (10) located over the top of the vulcanised rubber sole (6). Encapsulation of the polyurethane lower area (10) together with the vulcanised rubber sole (6) eliminates the need for injection operation. As an alternative, the vulcanised rubber sole (6) can be pre-filled on the inside with low-density and visco-elastic polyurethane (PU) material or ethylene vinyl acetate (EVA) material. In this case, its outside layer can be made of rubber or rubber combined with low-density polyurethane (PU) material or ethylene vinyl acetate (EVA) material to form the rubber sole (12). This way, the inner part of the sole of the safety boot (1) is made of ethylene vinyl acetate (EVA) material or low-density and visco-elastic polyurethane (PU) material, while its outside layer can be a solid structure made of rubber. The ethylene vinyl acetate (EVA) material used in the sole of the safety boot (1) has heat and cold isolation properties. In addition, thanks to its flexible structure and impact resistance it provides comfort in use. (Image-3)

The vulcanised rubber sole (6) used as the outer sole can be made of thermoset rubber materials like vulcanised rubber, nitrile rubber (NBR) and natural rubber, as well as thermoplastic elastomers (TPE) or combinations of these according to the intended purpose. (Image-1)

Alternatively, polyurethane can also be chosen as the material for the vulcanised rubber sole (6). The vulcanised rubber sole (6) can be produced at the desired density using the polyurethane raw material mixture injection method.

Toe protectors are placed at the toe tip of the core during production to protect the safety boot (1) against impacts at the toe area in order to meet requirements of EN-12568. Toe protectors are placed at the toe area of the safety boot (1), between the outer layer (3) and the polyurethane leg (5). Toe protectors used in production can be made of steel, aluminium or composite material according to producer's preference.

Metallic or non-metallic protective materials can be added to the safety boots (1) to provide sufficient puncture resistance according to ASTM-F 2413, CSA-195 and EN-12568 standards. Steel or Kevlar protective materials can be used to provide puncture resistance according to producer's preference. Steel or Kevlar protective materials are placed end-to-end in the sole area of the safety boot (1), between the outer layer (3) and the polyurethane leg (5). (Image-2) This way, a light, durable, certifiable and puncture-resistant safety boot (1) which satisfies safety requirements and footwear regulations can be provided.

Production of a Safety Boot (1) Comprising Two Distinct Lavers

Step 1: The inner layer (2) is pulled onto the core; Step 2: The outer layer (3) is sewn as a sock, leaving certain points loose; Step 3: The points sewn loosely create injection points (7) on the outer layer

(3);

Step 4: The outer layer (3) is pulled over the inner layer (2); Step 5: The polyurethane material is injected into the injection points (7) created on the outer layer (3);

Step 6: The polyurethane material diffuses from the injection points (7) on the outer layer (3) and moves towards the inner layer (2);

Step 7: The diffused polyurethane material cures and forms bridges (13) between the inner layer (2) and the outer layer (3);

Step 8: Formation of bridges (13) by the polyurethane material diffused from the injection points (7) attaches the inner layer (2) and the outer layer (3) to each other;

Step 9: An air gap (4) is formed between the inner layer (2) and the outer layer (3) which are attached to each other at only a limited number of points;

Step 10: The sole material made of rubber is placed next to the mould for the vulcanised rubber sole (6);

Step 11: The polyurethane material is injected onto the vulcanised rubber sole (6) at the injection area (8);

Step 12: The polyurethane leg (5) is formed by the injected polyurethane material;

Step 13: The sole mould is opened; Step 14: The materials on the produced safety boot (1) are left to cure for a sufficient period of time and then the safety boot (1) is removed from the mould. As seen in the order of steps listed above, the production method for the safety boot (1) with enhanced properties creates an air gap (4) during production. This air gap (4) enhances heat isolation. This allows the users to use the safety boots (1) in a wide range of temperatures and eliminates the problems experienced with the work and safety boots used in the current state of the art. In addition, attachment of the inner layer (2) placed onto the core at the first step of safety boot (1) production at injection points (7) located on the upper layer allows recovery of the inner layer (2) in case of any potential production error and allows their reuse rather than scrapping these parts as wastage.

Claims

1. A safety boot (1) having two layers, characterised by; a. Attachment of the inner layer (2) and the outer layer (3) through formation of at least one bridge (13) by curing of the material injected into at least one injection point (7) on the said outer layer and an air gap (4) created between the said inner layer (2) and the said outer layer (3) in result of this technique.

2. A safety boot (1) having two layers according to Claim-1, characterised by; a. At least one polyurethane lower area (10) located at the sole area of the said safety boot (1); and b. At least one polyurethane upper area (11) located at the leg area of the said safety boot.

3. A safety boot (1) having two layers according to Claim-2, characterised by; injection of polyurethane material at the sole injection area (9) of the said polyurethane lower area (10) and formation of the said polyurethane upper area (11) by injection of a polyurethane material with a different density at the injection area (8).

4. A safety boot (1) having two layers according to Claim-1, characterised by; the sole area of the said safety boot (1) having at least one rubber sole (12) of solid structure.

5. A safety boot (1) having two layers according to Claim-4, characterised by; the inner part of the said rubber sole (12) being made of ethylene vinyl acetate (EVA) material or low-density visco-elastic polyurethane (PU) material and its outer part being made of rubber material.

6. A safety boot (1) having two layers according to Claim-1, characterised by; attachment of the said inner layer (2) and the said outer layer (3) to each other by injection of the polyurethane material into the said injection points (7) located at a limited number of points on the said outer layer (3) and formation of bridges (13) between the said inner layer (2) and the said outer layer (3) in result of curing of the said polyurethane material.

7. A safety boot (1) having two layers according to Claim-1, characterised by; a protective element placed at the toe area of the said safety boot (1) between the said outer layer (3) and the said polyurethane leg (5) and made of steel, aluminium or composite material according to producer's preference.

8. A safety boot (1) having two layers according to Claim-1, characterised by; a protective element placed end-to-end at the sole area of the said safety boot (1) between the said outer layer (3) and the said polyurethane leg (5) and made of steel or Kevlar material according to producer's preference.

9. A safety boot (1) manufacture process, characterised by; comprising the steps of;

Pulling the inner layer (2) onto the core;

Sewing the outer layer (3) as a sock, leaving certain points loose in order to create injection points (7) on the said outer layer;

Pulling the said outer layer (3) over the said inner layer (2);

Injection of the polyurethane material into the said injection points (7) created on the said outer layer (3);

Diffusion of the polyurethane material from the said injection points (7) on the said outer layer (3) and movement of the polyurethane material towards the inner layer (2);

Formation of bridges (13) between the said inner layer (2) and the said outer layer (3) by curing of the polyurethane material injected into the said injection points (7);

Attachment of the said inner layer (2) and the said outer layer (3) onto each other by formation of the said bridges (13);

Formation of an air gap (4) between the said inner layer (2) and the said outer layer (3) attached to each other at a certain number of points by the said bridges (13);

Placement of a sole material made of rubber next to the mould for the vulcanised rubber sole (6);

Injection of the polyurethane material onto the said vulcanised rubber sole at the injection area (8);

Formation of the polyurethane leg (5) by the injected polyurethane material;

Opening of the sole mould; and Leaving the materials on the produced safety boot (1) to cure for a sufficient period of time and then removing the safety boot (1) from the mould.