阅读说明：本技术 用于制造鞋类和鞋类部件的方法 (Method for manufacturing footwear and footwear components ) 是由 珍尼·图奥马斯·基塔宁 利亚姆·爱德华·普罗克特 于 2020-02-17 设计创作，主要内容包括：本发明涉及一种用于制造鞋类外底或内底的方法,包括以下步骤：(a)提供外底或内底的第一成型阴模,第一成型阴模包括通过使用与外底或内底的第一侧的形状相对应的第一母模热成型获得的至少一个成型塑料片材,(b)添加液态可固化组合物到第一成型阴模,以及(c)固化可固化组合物,其中获得固化的外底或内底,并且其中将第一成型阴模从固化的外底或内底中移除。(The invention relates to a method for manufacturing an outsole or insole for footwear, comprising the following steps: (a) providing a first female mould of an outsole or insole, the first female mould comprising at least one shaped plastic sheet obtained by thermoforming using a first master mould corresponding to the shape of a first side of the outsole or insole, (b) adding a liquid curable composition to the first female mould, and (c) curing the curable composition, wherein a cured outsole or insole is obtained, and wherein the first female mould is removed from the cured outsole or insole.)

1. A method for manufacturing an outsole or insole for footwear, comprising the steps of:

(a) providing a first female mold for an outsole or an insole, the first female mold comprising at least one molded plastic sheet obtained by thermoforming using a first female mold corresponding to the shape of a first side of the outsole or the insole,

(b) adding a liquid curable composition to the first female mold, and

(c) curing the curable composition, wherein a cured outsole or insole is obtained.

2. A method according to claim 1, wherein in step (c) the obtained cured outsole or insole is removed from the first female mould.

3. The method of any one of claims 1-2, wherein after performing step (b), a planar sheet is placed on top of the liquid curable composition.

4. A process according to any one of claims 1-2, wherein after performing step (b) a second negative mould of the outsole or insole is placed on top of the partially cured liquid curable composition, the second negative mould comprising at least one shaped plastic sheet obtained by thermoforming.

5. A process according to any one of claims 1 to 4, wherein an outsole or insole is produced in step (a), and wherein during step (c) a further layer of a different liquid curable composition is added on top of the partially cured curable composition, and wherein the second negative mould if present or the planar sheet if present is removed prior to the addition of the different liquid curable composition.

6. The method of claim 1, wherein in step (a) the first female forming tool is combined with a third female forming tool of the outsole or insole to obtain a complete mold of the outsole or insole, the third female forming tool comprising at least one shaped plastic sheet obtained by thermoforming using a third master mold corresponding to the shape of the second side of the outsole or insole, and in step (b) the liquid curable composition is added to the complete mold through the gate opening.

7. A method according to claim 6, wherein in step (c) the obtained cured outsole or insole is removed from the first and third female mould.

8. A method according to any one of claims 1 to 5, wherein in performing step (b) the first female forming tool is supported by the first female tool or by a support of the same shape.

9. The method of claim 8, wherein in step (b), the master mold or the identically shaped support is cooled when the temperature of the liquid curable composition added in step (b) is above the softening point of the shaped plastic sheet of the first female mold.

10. A method according to any one of claims 1 to 9, wherein the sheet of formed plastic of the first female forming die is obtained by thermoforming in a continuous process using a thermoforming packer.

11. A method according to any one of claims 4 to 10, wherein the shaped plastic sheet of the second female mould is obtained by thermoforming in a continuous process using a thermoforming packer.

12. The method of any one of claims 1-11, wherein the first master mold of step (a) is obtained by 3D printing.

13. The method of any one of claims 1-12, wherein the liquid curable composition is a cold-cast cured composition.

14. The method of claim 13, wherein the cold-cast curable composition comprises a liquid TPU or a liquid PU.

15. The method of any one of claims 13-14, wherein the liquid curable composition further comprises regrinding injection molded EVA foam particles and/or reground injection molded PU particles.

16. The method of any one of claims 1-12, wherein the liquid curable composition comprises a polymer in a molten state.

17. A method of manufacturing footwear comprising the steps of: (i) manufacturing an outsole according to the method of any one of claims 1-16, (ii) placing an upper on top of the outsole obtained in step (i), and (iii) attaching the upper to the outsole.

18. A method according to claim 17, wherein in step (i) a further midsole is provided on top of the outsole according to the method of claim 5, and wherein in step (iii) an upper is attached to the obtained outsole and midsole.

19. A method according to any one of claims 17 to 18, wherein an insole obtained by a method according to any one of claims 1 to 16 is placed in the footwear obtained in step (iii).

20. The method according to any one of claims 17-19, wherein the upper is obtained by a thermoforming process.

21. The method of any one of claims 17-20, wherein the joining in step (iii) is at least one of gluing, welding, high frequency welding, ultrasonic welding, laser welding, pressing, sewing, screwing, riveting, fusing, clamping, sealing, heat and pressure treatment, or steam treatment.

Technical Field

The present invention relates to a method for manufacturing footwear and footwear components.

Background

Footwear, hereinafter referred to as footwear, generally includes an upper and a 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 generally positioned between the foot and the ground. Such a sole structure may attenuate ground reaction forces, provide traction, and limit potentially harmful foot motions. Accordingly, the upper and the sole structure operate together to provide a comfortable structure that is well suited for a variety of activities.

The sole structure may include a number of layers that are conventionally referred to as an insole, 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 to enhance comfort. The midsole may be secured to the upper and forms a middle layer within the sole structure that attenuates ground reaction forces. The outsole forms the element of the sole structure that contacts the ground and is typically fashioned from a durable, wear-resistant, resilient material that may include a tread pattern to provide traction.

US2018/0229461 describes a method of forming an article of footwear by cutting an outsole assembly from a sheet of material into a plurality of rubber outsoles to form a rubber outsole component.

US2010/0064548 describes the manufacture of footwear having an upper and an outsole with raised portions. The method uses a mold that includes a last on which the upper is disposed, an upper mold component that is divided into two sides that moves laterally relative to the lower mold component between a first position and a second position, and the lower mold component moves vertically relative to the upper mold component between a third position and a fourth position. A material for footwear is injected into the mold.

WO2016/186837 describes a method of bonding a shoe sole to a shoe upper using adhesive particles selectively fused to a substrate using a laser array.

EP1872994 describes a process for preparing foamed shaped articles, such as shoes, by injecting 1, 2-polybutadiene into a mould. Curing is carried out in a mold.

WO18200360 describes a method of manufacturing an article of footwear in which the outsole is made of a UV radiation cured material. Such UV radiation cured materials require a certain minimum mold time to fully cure. When producing a large number of footwear, a large number of molds would be required. In addition, for one footwear design, different shaped molds are required to make footwear that is suitable for different sized feet. Such a mould is typically a metal part shaped by subtractive manufacturing, e.g. machining, of a metal starting body. Therefore, this manufacturing method requires a large number of complicated molds.

Disclosure of Invention

It is an object of the invention to provide a simpler method by which parts of footwear, even the entire footwear, can be manufactured. More particularly, it is an object to provide a manufacturing method which does not require a large number of metal molds.

This object is achieved by the following method. The method for producing a footwear outsole or insole comprises the following steps:

(a) providing a first female mold for an outsole or an insole, the first female mold comprising at least one molded plastic sheet obtained by thermoforming using a first master mold corresponding to the shape of a first side of the outsole or the insole,

(b) adding a liquid curable composition to the first female mold, and

(c) curing the curable composition in the negative mold, wherein a cured outsole or insole is obtained.

This method is advantageous because curing takes place in a relatively readily available female mould made of plastic sheet. Such a mold can be mass-produced by thermoforming. This process requires only one or a limited number of relatively complex master molds, as compared to prior art processes that require many such molds as described above. Thus, the time-consuming curing in step (c) takes place in a one-shot female mould made of plastic material, which can be removed from the outsole or insole. Thus, higher throughput is achieved without having to make more master molds as in the prior art methods. In this method, the removed plastic mold can be recycled. Further advantages will be described when the invention is discussed in more detail below.

In this specification, the terms above, below, upper, bottom, lower, and the like may be used. These terms are used to more clearly illustrate the invention as it will be commonly used. For example, with respect to footwear, these terms are used in a direction generally used by footwear in which the outsole is the bottom and the upper is the upper end of the footwear. Unless specified otherwise, terms like first, second, etc. do not denote any order of the processes. These terms do not limit the invention to this general application.

In step (a), a negative mold for forming an outsole or insole comprising a plastic sheet is provided. The mold may be constructed of only one molded plastic sheet leaving an open side. When the liquid curable composition is added in step (b), it is preferably added from above with the molding end face of the mold facing downward. In this way, the liquid curable composition remains within the mold. Such a mold can suitably be used for preparing an outsole or an insole having a flat surface on one side. Midsoles may also be made by this method. After step (b) is carried out, a planar sheet is suitably placed on top of the liquid curable composition.

After step (b) is carried out, a second negative mold of an outsole or insole may be suitably placed on top of the liquid curable composition. This is advantageous in that a shaped bottom and a shaped upper side of the outsole or insole can be obtained. Step (c) is then carried out while the curable composition is present between the first female forming die and the second female forming die, so as to obtain a shaped outsole or insole. The second female mold of the outsole or insole suitably comprises at least one sheet of molded plastic obtained by thermoforming with a second female mold corresponding to the shape of the second side of the outsole or insole. This second side may be the upper side of the outsole or insole or the upper side of the material layer of the outsole or insole, as will be explained in more detail below.

The first and second female forming dies may be connected to each other or pressed together by a press or by a support as discussed below. In one embodiment, the first and second female forming dies may be sealed together to obtain a package of cured product. The packaged outsole and in particular the insole can thus be transported to another location or provided as the product itself.

With the method of the invention it is also possible to produce a layered outsole or a layered insole product. Delamination here means that different layers are stacked on top of each other and that the materials and/or properties of adjacent layers are different. Suitably an outsole or insole is produced wherein a further layer of a different liquid curable composition is added on top of the partially cured curable composition during step (c). Whereby step (c) is performed while the partially cured curable composition is present in the first female forming die. Any optional planar sheet or second female forming mold is first removed prior to adding the different liquid curable composition.

Another layer is added to the base layer as described above. The other layer may be covered by a planar sheet or by a fourth forming die. The fourth forming die is suitably a formed plastic sheet obtained by thermoforming using a fourth master die corresponding to the shape of the upper side of the next layer.

The process of adding another layer may be repeated to obtain a multi-layer outsole, midsole and insole.

The first female forming die can also be combined with the third female forming die to obtain a complete mold of the outsole or insole before step (b) is carried out. Adding a liquid curable composition to the complete mold via the gate opening in step (b). Preferably, the third female mold half comprises at least one molded plastic sheet obtained by thermoforming using a third female mold half corresponding to the shape of the second side of the outsole or insole.

In step (b), the first female forming die is suitably supported by the first female die or by a support of the same shape. In a continuous process, it may be preferred to use the same shaped support so that the master mold can be used to produce the next first female mold or the next set of first female molds. By being identically shaped, the support will have a surface of the same shape as the master mold. This results in the molding surface of the first female molding die being equally supported along its surface by the support.

The planar sheet or the second forming die as described above may also be supported by a support. This is advantageous to ensure that the outsole or insole obtains its desired shape in step (c). In the case where the flat sheet requires a support or a second master mold, the support may be a flat plate. Preferably, the support is the same shaped support or more preferably a molded concave support as compared to the second master mold.

The support may be cooled while performing step (b). This is particularly advantageous when the liquid curable composition added in step (b) has a temperature above the softening point of the sheet of shaped plastic of the first female mould. The support may also be heated to enhance the polymerization reaction as described below. The heating or cooling can be effected, for example, by air or water cooling on the side of the support not facing the female mould.

In step (c), curing of one or more curable compositions may be carried out while supporting the female mold as described above. Since curing may take some time before a fully cured product is obtained, it is preferred to remove the support from the mold when the curable composition has reached a substantially stable shape. The products may then be removed from their supports in step (c) and stored elsewhere to fully cure as they are present within their forming dies. This is particularly advantageous when, for example, a dimensionally stable product is obtained quickly, such as, for example, within a few minutes to an hour, and when a fully cured product is obtained after 24 hours. The obtained fully cured or cured outsole or insole is removed from the first negative mould and optionally a further third negative mould to obtain a product for use as part of footwear.

The molded plastic sheet is obtained by thermoforming. Thermoforming is a manufacturing process in which a plastic sheet is heated to a pliable forming temperature and formed into a particular shape in a master mold. The sheet is heated to a temperature high enough to be stretched into or onto a mold and then cooled to its final shape. When the mould comprises two shaped plastic sheets, these are preferably manufactured by thermoforming and subsequently interconnected.

The plastic sheet may be any type of plastic, in particular a plastic suitable for thermoforming. When, for example, the radiation curable composition is used as a liquid curable composition, the plastic sheet should not be a barrier to radiation. For this reason, when the radiation is visible light or ultraviolet radiation, it is preferable to use a light-transmitting sheet. When the radiation is, for example, microwaves, it is preferable to use a plastic sheet that does not cause dielectric heating of the plastic sheet itself. The material used for the plastic sheet is preferably strong at the minimum sheet thickness. The plastic is suitably a thermoplastic polymer. Examples of suitable thermoplastic polymers are polyethylene, polypropylene, polycarbonate, preferably polystyrene. The thickness of the sheet may vary from 50 micrometers to even 5 millimeters, with the lower part of the range being useful for making smaller products and the upper part of the range being useful for making larger products. For example, to produce a product having a maximum dimension of less than 50 cm, the thickness of the sheet may vary between 50 and 200 microns.

The first mother die, the second mother die, the third mother die, and/or the fourth mother die used in the thermoforming method may be obtained by 3D printing or subtractive manufacturing. Subtractive manufacturing, such as machining of a suitable metal body, can be performed using, for example, computer numerical control machining.

The same shaped support as described above used in step (b) and/or step (c) may also be obtained by 3D printing or subtractive manufacturing as described above.

Preferably, the above-mentioned master model, the second to fourth master models and/or the above-mentioned support are obtained by 3D printing, as this enables one to manufacture different footwear designs without having to use laborious techniques like machining to prepare the master model. The 3D printing of these items makes it easier to develop new designs of outsoles, insoles and complete footwear. One or more master molds and optional forming supports can be used to quickly produce a small number of prototypes. The same mold and support can also be used for mass production if new designs are to be mass produced.

The skilled practitioner can print a variety of materials using a variety of 3D printing techniques, including gypsum, thermoplastics, photopolymerizable polymers, or thermally sintered materials. Specific examples of suitable materials and additive manufacturing techniques are ABS plastics manufactured using fused Deposition modeling fdm (fused Deposition modeling), nylon for selective Laser sintering SLS (selective Laser sintering), and nylon for selective Laser sintering SLSSuitable printers are, for example, FDM 3D printers manufactured by Ultimaker, SLS printers, such as ProX SLS 6100 manufactured by 3D Systems, and MJF printers manufactured by HP thermoplastics.

When the master model is manufactured by 3D printing using a material having low thermal conductivity as described above, it is preferable that the master model is provided with a plurality of openings that fluidly connect a molding surface of the master model, the molding surface facing the female molding die of the 3D product and the opposite side thereof. The thickness of the master is preferably between 0.5 and 5 mm. The diameter of the holes is typically less than 2mm, preferably less than 1mm in diameter. The openings allow air to escape through the master mold during the molding process. The master tool is suitably also provided with channels for passing a fluid cooling medium along opposite sides of the shaping surface. The cooling of the master mold enhances the negative mold of the 3D product produced to solidify in its desired shape in the master mold. The fluid cooling medium may be a gas (e.g., air), or a liquid (e.g., water) or a specific heat transfer fluid (e.g., ethylene glycol or propylene glycol).

Thermoforming is suitably carried out in a continuous process using a thermoforming wrapper. Such thermoforming packaging machines are well known. Such machines enable one to prepare a plurality of dies in a continuous process starting from a roll of sheet material or from an extruder that provides the sheet material. Such a thermoforming packaging machine may comprise one or two thermoforming stations, an optional sealing station, a filling station to which a curable composition is added, and a cutting station. When the second female forming die is produced by thermoforming, there are preferably two thermoforming stations. The first thermoforming station uses a first master mold, and the second thermoforming station uses a second master mold. In the cutting station either individual moulds or interconnected sets of moulds are obtained. The cutting station may be upstream of the filling station or downstream of the filling station. The individual molds or mold sets containing the curable composition may be stored to allow the curable composition to cure.

In step (b), the liquid curable composition is added to the mold. The addition of the liquid curable composition may be carried out by pouring the composition into a mould, for example as is known from open casting moulding processes. Pouring may be performed by adding the composition to the mold from above, for example to the open upper end of a simple one-piece mold or through the gate opening of a complete mold as described above.

In step (c), all or part of the liquid curable composition present in the mould is cured. Solidification may occur by reaction and/or may be the result of a phase change. Solidification by phase change is suitably achieved with a liquid curable composition comprising a polymer in a molten state. Such polymers may be scrap or recycled polyethylene or polypropylene or mixtures thereof. By adding these compounds in their liquid, molten phase, these materials can be reused and useful parts of footwear produced. The temperature of the molten polymer may be high and/or the polymerization itself may lead to a temperature increase and for these reasons it may be necessary to cool in step (b) and optionally also in step (c) as described above.

The curing reaction is suitably a polymerisation of the composition components. The polymerization may be initiated by spontaneous reaction between the components of the composition under the conditions of step (c), optionally in the presence of an initiator compound. The polymerization may be accelerated by carrying out steps (b) and (c) at higher temperatures, which may require cooling as described above.

The components of the curable polymeric composition are suitably mixed to obtain the composition just prior to performing step (b), or the components of the curable polymeric composition are maintained under conditions wherein polymerization does not occur in any significant manner. The conditions under which step (c) is carried out are preferably the environmental conditions mentioned for step (b). Alternatively, the polymerisation in step (c) may be initiated under the influence of ultrasound or radiation passing through the plastic sheet of the mould. The wavelength of the radiation will depend on the choice of radiation curable composition. Many radiation curable compositions require light in the UV band, but some radiation curable compositions cure when visible light is used. Alternatively, the radiation may be electromagnetic radiation, such as microwaves, radio waves or infrared.

Since step (c) is carried out in a relatively simple plastic mould, it is less important to achieve curing quickly, since curing can be carried out in a relatively simple mould for a relatively long time. This allows one to select curable compositions that require longer cure times. Such as a composition having a high propagation rate or a radiation-curable composition. When polymerization is initiated and propagated in the absence of radiation, the radiation curable composition may, for example, be exposed to radiation for an initial period of time and for a period of time without radiation.

Preferred curable compositions are so-called cold-cast curing compositions. The advantage is that no cooling of the mould as described above is required. Such liquid compositions are well known. They may be formulated prior to use and poured into moulds in step (b) at, for example, ambient conditions and cured to a solid in step (c) at, for example, ambient conditions. Examples of suitable cold-cast curing compositions are silicone rubbers, thermoplastic rubbers, natural rubbers and, where appropriate, Polyurethanes (PU) and Thermoplastic Polyurethanes (TPU). In the case of producing an insole, the liquid curable composition is preferably a silicone, such as a silicone rubber or a thermoplastic rubber. In the case of the production of outsoles, the liquid curable composition is preferably Polyurethane (PU) or Thermoplastic Polyurethane (TPU).

The above-mentioned ambient conditions may be between 5 ℃ and 50 ℃, preferably between 10 ℃ and 30 ℃ and the pressure may be between 0.08MPa and 0.12MPa, more preferably at ambient pressure.

The cold-cast curable composition may also include other components. Preferred further components are solid particles, for example added to adjust the density of the prepared product or to change other properties, such as compressibility. Applicants have found that cold-cast curable compositions can be combined with particles of cork, injection molded Thermoplastic Polyurethane (TPU), injection molded Polyamide (PA), injection molded polyethylene terephthalate (PET), injection molded Ethylene Vinyl Acetate (EVA), and/or injection molded polybutylene terephthalate (PBT). These particles may advantageously be obtained in a footwear manufacturing process as described, for example, in US 2014066530. Advantageously, these particles can be obtained from used footwear. US2016302508 describes an exemplary footwear made of only one of the listed materials. This enables one to recover one type of material in a simple manner. Such recycled material may advantageously be used as part of a curable composition used as regrind material in step (b). Suitably, the liquid curable composition further comprises regrind injection moulded EVA foam particles and/or regrind injection moulded PU particles. More preferably, a layer of such recycled material may be cast on top of, for example, a TPU outsole as a midsole according to the above process.

The invention also relates to a method of manufacturing footwear comprising the steps of: (i) manufacturing an outsole according to the method of the invention, (ii) placing an upper on top of the outsole obtained in step (i), and (iii) attaching the upper to the outsole. Preferably, in step (i), an additional midsole is provided on top of the outsole, according to the method for layered products described above. In step (iii), the upper is then attached to the obtained outsole and midsole. Preferably, the insole obtained according to the method of the invention is placed in the footwear obtained in step (iii).

The upper may be any conceivable upper that may be combined with an outsole as described above. The selection of the upper depends on the type of footwear one wishes to make. Examples of possible footwear are shoes, boots, sandals, etc. The upper may be any material, such as a variety of suitable materials, including, for example, leather, textiles, synthetic materials (non-woven and microfiber backings), microfiber, spacer mesh, plastic, rubber, wood, natural fibers such as jute, and the like. The concrete material comprises EPM synthetic suede leather, EPM synthetic leather, poly nylon non-woven fabric, superfine fiber polyester fabric, polyester fabric or TPU coating synthetic leather. The upper may be open-toe or closed-toe. Similarly, the heel of the upper may be an open heel or a closed heel. The upper may also be obtained by a thermoforming process. Suitable materials for such an upper obtained by thermoforming may be any sheet that can be formed in a thermoforming process. Examples are Ethylene Vinyl Acetate (EVA) foam, leather, thermoplastic glass fibre composites, thermoplastic carbon fibre composites, knitted nylon fibres, breathable mesh PVC and breathable mesh polyester.

The upper may be attached to the outsole and insole by any known method. Suitably, the joining in step (iv) is at least one of gluing, welding, high frequency welding, ultrasonic welding, laser welding, pressing, sewing, screwing, riveting, fusing, clamping, sealing, heat and pressure treatment, or steam treatment.

Drawings

The invention will be illustrated by means of figure 1. Fig. 1 is a schematic view of a possible continuous process for manufacturing an outsole for footwear. In the upper drawing of fig. 1, a roller 1 is shown, from which a plastic sheet 4 extends to the left side of the drawing. The sheet 4 runs between the upper and lower mould parts 2, 3 of the thermoforming station. The lower mold part 3 includes a master mold on its upper side. In the following figures, the upper and lower mould parts sandwich the plastic sheet 4, so that a negative mould 5 of the outsole is obtained. The mould 5 is filled with a liquid curable composition from a container 6. The mold with the curable composition is shown as filled mold 7. The mold with the fully cured composition is shown as mold 8. Outsole 7a may be separated from the mold or retained in the mold for bonding with other footwear components, as shown in fig. 3.

FIG. 2 illustrates a well-known method of thermoforming a web of material from which to form an upper. A sheet 13 of, for example, EVA foam is pulled to the left from the roller 10. The sheet 13 runs between the upper and lower mould parts 11, 12 of the thermoforming station. The lower mold part 12 includes a master mold on its upper side. In the following figures, the upper and lower mold members sandwich the sheet 13, so that the upper 13 is obtained.

Figure 3 shows the arrangement of figure 1 as part of a footwear manufacturing process. The mold 8 with the cured outsole 7a is bonded to the midsole 14 on top of the outsole 7 a. When the midsole 14 is secured to the outsole 7a, the outsole 7a need not be completely cured. On top of the stack of outsole 7a and midsole 14 as shown in fig. 4, an upper 13 is placed (see also fig. 5). Upper 13 may be any upper or an upper made by the method shown in fig. 2. In the sealing station 15, the upper 13 is attached to the outsole.

Fig. 6 shows an outsole 7a of a different package sandwiched between a first female forming die 23 and a second female forming die 28.

Detailed Description

The invention will be further illustrated by the following non-limiting examples.

Examples

Reference will be made in this embodiment to fig. 7 to 10, which schematically show the different steps and dies used in this embodiment. In this example, an outsole 29 is prepared according to the method of the present invention. The first master mold 22 made of ABS was prepared using Fused Deposition Modeling (FDM). The master 22 is printed in four separate pieces and assembled in one piece. The first mother die 22 is shaped like a concave shape of the bottom of the outsole 2. Mold 22 is only slightly larger than the exact concave shape of the desired outsole 29. Also, the second master mold 27 is made of ABS using Fused Deposition Modeling (FDM). Similarly, the second master mold 27 is printed in four separate pieces and assembled in one piece. The second master model 27 resembles the concave shape of the top end of the outsole 29 to be prepared. The first master mold and the second master mold were prepared within 12 hours. When using faster and more printers, it is conceivable that such a process could be completed in even shorter time. Using a larger printer would enable one to make the first and second molds in one piece by 3D printing.

A first female molding die 23 of an outsole was obtained by thermoforming using the above-described first master die 22, the first female molding die 23 consisting of one molded plastic sheet 21 of a thermoplastic elastomer having a thickness of 0.22 mm. The mold 23 has a flat surface 23a and grooves 23b in the flat part 23a corresponding to the bottom of the outsole 29 and sides of the outsole 29.

A second female mold 28 of an outsole 29 was obtained by thermoforming using the above-described second master mold 27, the second female mold 28 consisting of one molded plastic sheet 25 of a thermoplastic elastomer having a thickness of 0.22 mm. The master mold 27 has a flat portion 27a and grooves 27b in the flat portion 27a corresponding to the top of the outsole 29 and a portion of the sides of the outsole 29.

The first female forming die 23 and the second female forming die 28 were produced using a standard thermoforming packaging machine at a rate of 6 per minute. This can be improved by using more master moulds at the same time and/or by using a larger thermoforming wrapper.

The first female forming die 23 is put back into the first support 30 having the same shape as the first female die 22. A cold-cast industrial liquid rubber product called PMC-770, obtained from FormX of amsterdam, the netherlands, is cast into the groove 23b of the first female forming die 23 at room temperature and ambient pressure. The added volume 29a is about the volume of the desired outsole 29. After the cold-cast curable composition is added, the second female forming die 28 is placed on top of the filled first female forming die such that the flat surfaces 23a, 28a contact each other and wherein the second female forming die 28 slightly presses down the top surface 29b of the cold-cast liquid. Any excess liquid can escape through purge lines (not shown) in one or both of the flat surfaces 23a, 28 a. On top of the second female forming die 28a second support 31 is placed and the whole stack obtained is pressed together. Since the second female molding die has an extension, i.e., a groove 28a, which penetrates partially cured liquid (see, for example, fig. 10), the support 31 is also a female molding die of the second mother die 27.

After 15 minutes, the first support 30 and the second support 31 are removed from the stack, and after 12 hours, the completely cured outsole 29 is removed from the filled set 34 of the two thermoplastic elastomer molds 23, 28. This clearly shows the advantage of this method in that the time required to use a complex master tool 22, 27 or forming support 30, 31 during the curing process is relatively short. The use of inexpensive and disposable thermoplastic elastomer molds 23, 28 can extend the curing time. The molds 23, 28 may be recycled after use as sheets of material that may be reused in the thermoforming process.

In this embodiment, the mold 22 or the supports 30, 31 are not cooled or heated. But this can be done by gas flow 33 or liquid flow 32, as shown in fig. 9 and 10, if desired. Similar shaped products have been prepared by this method using urethane rubber PMC-780WET, urethane rubber PMC-780DRY and urethane TASK 16 adhesives instead of the above-described cold-cast industrial liquid rubber.

In this embodiment, the outsole is prepared with a shaped bottom and an upper side. The method can also be used for manufacturing other objects or multi-layer objects. The invention therefore also relates to a method for producing any product, comprising the following steps:

(a) providing a first female forming die at one end of the product, the first female forming die comprising at least one shaped plastic sheet obtained by thermoforming using a first female die corresponding in shape to one end of the product,

(b) adding a liquid curable composition to the first female mold,

(b1) placing a second female forming die on the other side of the product on top of the partially cured liquid curable composition, the second female forming die comprising at least one shaped plastic sheet obtained by thermoforming, and

(c) curing the curable composition, wherein a cured product is obtained.

The preferred embodiment is that of the outsole and insole described above.