US-12617169-B2 - Process for manufacturing a footwear and footwear parts

US12617169B2US 12617169 B2US12617169 B2US 12617169B2US-12617169-B2

Abstract

The invention is directed to a process for producing a outsole or inner sole of a footwear comprising the following steps (a) providing a first form negative mould of the outsole or inner sole comprising of at least one formed plastic sheet as obtained by thermoforming using a first master mould corresponding with the shape of a first side of the outsole or inner sole, (b) adding a liquid curable composition to the first form negative mould, and (c) solidifying the curable composition wherein a solidified outsole or inner sole is obtained and wherein the first form negative mould is removed from the solidified outsole or inner sole.

Inventors

Janne Tuomas KYTTANEN
Liam Edward PROCTOR

Assignees

WHAT THE FUTURE B.V.

Dates

Publication Date: 20260505
Application Date: 20200217
Priority Date: 20190311

Claims (20)

1 . Process for producing an outsole or inner sole of a footwear comprising the following steps: (a) providing a first form negative mould of the outsole or inner sole comprising of at least one formed plastic sheet as obtained by thermoforming using a first master mould corresponding with the shape of a first side of the outsole or inner sole, (b) adding a liquid curable composition to the first form negative mould, wherein the liquid curable composition is a cold pour composition, and (c) solidifying the curable composition wherein a solidified outsole or inner sole is obtained and wherein in step (c) the solidified outsole or inner sole as obtained is removed from the first form negative mould, wherein the formed plastic sheet of the first form negative mould is obtained by thermoforming using a thermoforming machine comprising of a thermoforming station, a filling station and a cutting station in a continuous process, wherein in the thermoforming station step (a) is performed by preparing numerous first form negative moulds in a continuous process starting from a roll of sheet or from an extruder providing a sheet thereby obtaining a continuous sheet of interconnected first form negative moulds, wherein in the filling station step (b) is performed by adding the liquid curable composition to the first form negative moulds as prepared in the thermoforming station thereby causing the continuous sheet of interconnected first form negative moulds to contain the curable composition, wherein in the cutting station the continuous sheet of interconnected first form negative moulds containing the curable composition is cut into single first form negative moulds containing the curable composition or groups of first form negative moulds containing the curable composition, and wherein step (c) is performed by storing the single first form negative moulds containing the curable composition or the groups of first form negative moulds containing the curable composition as obtained in the cutting station elsewhere from the thermoforming machine.
2 . Process according to claim 1 , wherein after performing step (b) a second form negative mould of the outsole or inner sole comprising of at least one formed plastic sheet as obtained by thermoforming is placed on top of the liquid curable composition of step (b) that has been partly cured.
3 . Process according to claim 2 , wherein the formed plastic sheet of the second form negative mould is obtained by thermoforming using a thermoforming packaging machine in a continuous process.
4 . Process according to claim 1 , wherein in step (a) an outsole or inner sole is produced and wherein during step (c) a further layer of a different liquid curable composition is added on top of the liquid curable composition of step (b) that has been partly cured.
5 . Process according to claim 1 , wherein in step (a) the first form negative mould is combined with a third form negative mould of the outsole or inner sole comprising of at least one formed plastic sheet as obtained by thermoforming using a third master mould corresponding with the shape of a second side of the outsole or inner sole to obtain a full mould of the outsole or inner sole and that in step (b) the liquid curable composition is added to the full mould via a gating opening.
6 . Process according to claim 5 , wherein in step (c) the solidified outsole or inner sole as obtained is removed from the first and third form negative mould.
7 . Process according to claim 1 , wherein the first form negative mould is supported by the first master mould or by an equally shaped support when performing step (b).
8 . Process according to claim 7 , wherein in step (b) the master mould or the equally shaped support is cooled when the temperature of the liquid curable composition added in step (b) is higher than the softening point of the formed plastic sheet of the first form negative mould.
9 . Process according to claim 1 , wherein the thermoforming machine is a thermoforming packaging machine.
10 . Process according to claim 1 , wherein the first master mould of step (a) is obtained by 3D printing.
11 . Process according to claim 10 , wherein the thickness of the master mould is between 0.5 and 5 mm.
12 . Process according to claim 10 , wherein the material of the master mould is ABS Plastic manufactured using Fused Deposition Modelling FDM, or Selectively Laser Sintered SLS Nylon.
13 . Process according to claim 1 , wherein the cold pour curing composition is selected from silicone, rubber, thermoplastic rubber, natural rubber, polyurethane (PU), thermoplastic polyurethane (TPU), and combinations thereof.
14 . Process according to claim 13 , wherein the cold pour curing composition is liquid TPU or liquid PU.
15 . Process according to claim 13 , wherein the liquid curable composition further comprises regrind injection moulded EVA foam particles and/or regrind injection moulded PU particles.
16 . Process according to claim 1 , wherein the liquid curable composition comprises a polymer in its molten state.
17 . Process to manufacture a footwear comprising the following steps, (i) manufacture of an outsole according to the process according to claim 1 , (ii) placing an upper on top of the outsole obtained in step (i) and (iii) connecting the upper to the outsole.
18 . Process according to claim 17 , wherein in step (i) a further midsole is provided on top of the outsole according to the process of claim 5 and wherein in step (iii) the upper is connected to the obtained outsole and midsole.
19 . Process according to claim 17 , wherein an inner sole as obtained by a process according to claim 1 is placed in the footwear obtained in step (iii).
20 . Process according to claim 17 , wherein the upper is obtained by a thermoforming process.

Description

The invention is directed to a process for manufacturing a footwear and footwear parts. Footwear, hereafter referred to as a shoe, normally include both an upper and sole structure. The upper generally forms an interior void that securely and comfortably receives a foot. The sole structure may be secured to the upper and is generally positioned between the foot and the ground. This sole structure may attenuate ground reaction forces, provide traction, as well as limit potentially harmful foot motion. Accordingly, the upper and sole structure operate together to provide a comfortable structure that is well suited for use in a wide variety of activities. The sole structure may comprise multiple layers that are conventionally referred to as an inner sole, a midsole, and an outsole. The insole is a thin, compressible member located within the void of the upper and adjacent to the midsole and the foot in order to enhance comfort. The midsole may be secured to the upper and forms a middle layer in the sole structure that attenuates the ground reaction forces. The outsole forms the element of the sole structure that makes contact with the ground and is usually fashioned from a durable and wear-resistant elastomeric material that may include a tread pattern to impart traction. US2018/0229461 describes a process to form a footwear article by forming a rubber outsole component by cutting the outsole component into the plurality of rubber outsoles from a sheet. US2010/0064548 describes the manufacture of a footwear having an upper and an outsole with an upraised portion. The method uses a mould comprising a last, upon which the upper is arranged, an upper mould part divided into two side parts being laterally movable in relation to a lower mould part between a first and second position, and the lower mould part being vertically movable in relation to the upper mould part between a third and fourth position. The material for the footwear is injected into said mould. WO2016/186837 describes a method to bond a shoe sole bonded with a shoe upper using an adhesive particulate is selectively fused to the substrate with a laser array. EP1872924 describes a method to make a foam-molded article such as a shoe by injecting 1, 2-polybutadiene into a mould. The curing takes place in the mould. WO18200360 describes a process to manufacture a footwear product wherein the outsole is made from a UV radiation cured material. Such a UV radiation cured material requires a certain minimum mould time to fully cure. When producing high numbers of footwear a large number of moulds will then be required. Furthermore for one footwear design differently shaped moulds are required in order to manufacture footwear for differently sized feet. Such moulds are typically metal parts which have been shaped by subtractive manufacturing such as machining a metal starting body. Thus this method of manufacture requires numerous complex moulds. The object of the present invention is to provide a simpler process which can manufacture footwear parts and even the entire footwear. More especially the object is to provide a manufacturing process which does not require numerous metal moulds. SUMMARY This object is achieved by the following process. Process for producing a outsole or inner sole of a footwear comprising the following steps (a) providing a first form negative mould of the outsole or inner sole comprising of at least one formed plastic sheet as obtained by thermoforming using a first master mould corresponding with the shape of a first side of the outsole or inner sole, (b) adding a liquid curable composition to the first form negative mould, and (c) solidifying the curable composition in the form negative mould wherein a solidified outsole or inner sole is obtained. This process is advantageous because the curing takes place in a relatively easily obtainable form negative mould made of a plastic sheet material. Such moulds may be manufactured in high numbers by thermoforming. This process requires only one or a limited number of relatively complex master moulds as compared to the prior art methods which require many of such moulds as explained above. The time consuming curing in step (c) thus takes place in a disposable form negative mould made of a plastic material which can be removed from the outsole or inner sole. Thus a higher production capacity is obtained without having to manufacture more master moulds as in the prior art processes. The removed plastic mould may be recycled for reuse in the process. Further advantages will be described when discussing the invention in more detail below. In this description terms as above, below, upper, bottom and lower may be used. These terms are used to more clearly illustrate the invention as it would be generally applied. For example for footwear the terms are used for the orientation at which the footwear is generally used wherein the outsole is the bottom and an upper is typically the upper end of t