EP3397804A1

EP3397804A1 - Process of treating a non-woven microfibrous matrix material with resin

Info

Publication number: EP3397804A1
Application number: EP16838033.5A
Authority: EP
Inventors: Carlo BORSANI; Marco SECCO D'ARAGONA
Original assignee: Naum Srl
Current assignee: Naum Srl
Priority date: 2015-12-30
Filing date: 2016-12-29
Publication date: 2018-11-07
Also published as: IT201600132183A1; WO2017115312A1; ITUB20159810A1

Abstract

A process of treating a resin-impregnated microfibrous non- woven matrix, characterized in that it includes the following treatment steps: - providing a microfibrous non- woven matrix having a top surface to be treated; - preparing said top surface of said matrix by hot calendering and/or buffing; - grouting said matrix by depositing and distributing a base resin coat thereon; - performing a micro-droplet spray deposition of one or more resins, a hot drying step being carried out on said matrix between the deposition of one layer and the deposition of the next layer, preferably an oven-drying step at a temperature ranging from 80°C to 150°C, more preferably at a temperature ranging from 90°C to 110°C; - hot embossing the surface of said matrix, said embossing step being carried out by partial melting of the fibers of said matrix, to cause a permanent deformation in said fibers of said matrix; - performing a micro-droplet spray deposition to form one or more continuous protective layers of one or more resins.

Description

"PROCESS OF TREATING A NON-WOVEN MICROFIBROUS MATRIX MATERIAL WITH RESIN" DESCRIPTION

The present invention is intended to provide protection to a process of treating a non- woven microfibrous matrix with resin.

The use of animal hides in various fields of application, e.g. in fashion and linings, especially when a combination of quality, strength and elegance is desired. Hides are appropriately treated, prepared and mounted for improving their aesthetic appearance and resistance to various stresses.

Nevertheless, animal hides has a number of drawbacks: each hide is different from the others, even if they are of the same species, in terms of mechanical resistance, thickness and their various inherent physical and aesthetic properties, which are typically desired by its users.

According to the environment in which the animal was grown and lived and to the part of the animal in use, the hide may be exposed to thickness and mechanical resistance alterations. Furthermore, hides may exhibit unevenness due to diseases, accidents, scratches, etc. This causes difficulties to leather working factories, which require a homogeneous product for later use, and will incur higher cost during pre-treatment. Furthermore, raw natural hides are the subject of hard negotiations in special commodities exchange, due to a relatively restricted market; this will expose market operators to the risk of being victims of speculations, resulting in unsteady costs and unavailability of hides.

Finally, the birth and development of new purchase-related philosophical conceptions, directed to a greater care for the environment and animals, motivate the factories that sell or manufacture leather or leather-containing products, to find alternative solutions that might provide pleasant effects, in terms of elegance and touch, such that the finished product might ensure a high-quality, natural leather-like perception in consumers.

Alternatives to animal hides are currently available in the market, such as "imitation leather", also known as "eco-leather" or "synthetic leather". The latter is manufactured from release paper, with the operator depositing thereon various resin layers: each deposition is followed by drying, which will provide a homogeneous film, whose surface pattern is imparted by the release paper itself.

The last pass, with the resin still in a fluid state, is the deposition of a textile support which imparts physical and phenotypic properties to the product. It will be understood that such product may cause problems in the adhesion of the various layers, with a risk of product peeling, especially under stress.

Furthermore, due to the physical properties of the films so created, this type of product has poor breathability.

For the treated material to have the desired appearance, the release paper shall have any decorative elements preset thereon.

A well-known drawback thereof is that the manufacturer will have to handle large volumes of identical decorative elements.

This is because the release paper is usually available in large rolls, involving large-scale production.

Thus, imitation leather obviously looks different from natural leather, as identical serially repeated decorative patterns are recognized, and reveal the printing operation. Likewise, the feel is very different from the feel of natural leather.

Due to the above discussed problems, a leather-like product is obtained that has an apparent lower quality, such that is will be inadequate to meet the requirements of high- end manufacturers, typically in the automotive industry.

Manufacturing problems are also encountered, due to the sizes of the plants and raw materials in use, which often increase treatment costs, at least relative to the desired result.

Therefore, the invention has the object to conceive and provide a process of treating a microfibrous non-woven matrix that can be also carried out continuously and involves relatively low manufacturing and maintenance costs.

Namely, it has the object of providing a process of treating a microfibrous non- woven matrix that might lead to a product that is aesthetically identical to natural leather, preferably having an even thickness, and with a decorative pattern obtained without using release paper, preferably having breathable properties and meeting the requirements of those that cannot or do not want to use animal hides.

According to a further aspect another object of the present invention is to make and provide a product that is very similar to leather, in terms of physical and phenotypic properties.

These objects are fulfilled by the process as defined in claim 1, as well as by the use of a microfibrous non- woven material as defined in claim 16.

Further features and advantages of the process of the present invention and the microfibrous non-woven material will result from the following description of a few preferred embodiments thereof, which is given by way of illustration and without limitation with reference to the accompanying figures, in which:

- Figure 1 is a top view of the microfibrous material of the invention;

- Figure 2 is a 1 Ox-enlarged view of a detail of Figure 1 and

- Figures 3 and 4 are 1 Ox-enlarged cross-sectional views of the microfibrous material of Figure 1.

The treatment process of the invention includes the provision of a microfibrous non- woven matrix composed of one or more impregnated polyamide or polyester fibers, which may have been enriched - during manufacturing - with reinforcement elements, such as water-based polyurethane resins or solvent-based polyurethane resins. In certain cases, such products should be added with or even entirely made of collagen fibers. According to a preferred embodiment, the matrix is a non-microporous microfibrous non- woven matrix.

As used herein, the term "non-woven matrix" shall be intended as "a matrix made of a non- woven fabric".

The matrix so formed undergoes treatment through successive steps, as described hereinafter in detail for the novel and improved aspects thereof to be clearly recognized. At first, the top surface of the matrix is treated by hot calendering and/or buffing, for proper preparation to the subsequent steps of the process. In some cases, for certain treatments, both processing steps may be carried out. Furthermore, if needed, a coating resin may be also deposited, for reducing surface porosity.

If this is the case, once the matrix is ready, it will undergo a grouting step, with a resin base coat preferably made of a water-based or solvent-based polyurethane, being deposited and distributed over the top surface.

The coat is deposited using a reverse-cylinder printing machine, in which the cylinder deposits a layer of desired material on the substrate while rotating in a direction opposite to the matrix being fed.

Advantageously, the aforementioned grouting step C) may be carried out using a grouting roller rotating in a direction opposite to the surface to be grouted, to thereby form a smooth and compact layer on said surface of said microfibrous non-woven matrix. In practice, the surface to be grouted is fed in a preset direction of feed, whereas the grouting step C) is carried out using a counter-rotating grouting roller that contacts said surface to be grouted with a lateral surface portion whose peripheral tangential velocity is opposite to the direction of speed of the surface to be grouted.

The aforementioned grouting step will deposit 20 to 150 g/m² of resin, more preferably 30 to 50 g/m² of resin on the top surface of said microfibrous non- woven matrix.

The product so obtained is entirely comparable to a natural sanded leather, i.e. natural leather that has been tanned and has to undergo the well-known finishing process, as shown in Figure 1.

Then the material so treated may undergo a buffing step, such that its surface will be prepared for further processing and the adhesion properties of the top surface with the following layers will be increased.

Then, a continuous layer of resin material, preferably made of water- or solvent-based polyurethane, is deposited, using a micro-droplet spray printing technology, to form the various continuous layers required. This step is typically composed of a number of successive substeps, preferably at least three substeps, to provide an adequate thickness, for later processing to be performed by the operator as required. In order to ensure the desired tactile, visual and resistance properties, 10g/m² to 25 g/m² of material should be deposited for each of the continuous layers.

Preferably, as used herein, the term "micro droplets" is used to designate droplets with sizes ranging from 0.3 to 1.1 mm, more preferably from 0.4 to 0.8 mm.

The spray deposition of a continuous layer is separated from the spray deposition of the next continuous layer by hot drying of the matrix, preferably at a temperature ranging from 80°C to 150°C, more preferably at a temperature ranging from 90°C to 110°C, Preferably such hot drying step on the aforementioned matrix consist in an oven-drying step.

Therefore, according to the preferred embodiment suggested herein, the required processing steps for spray deposition of a continuous layer of resin are alternated with as many oven-drying steps, at a temperature ranging from 80°C to 150°C, for the time required for thorough drying of the deposited layer, for maximized coating of the surface, and preparation thereof to the next steps. An optimal range from 90°C to 1 10°C resulted from experimental tests.

The amount of resin that is sprayed during such step of spray deposition of a continuous layer of resin may range from 2 to 50 g/m , more preferably from 10 to 20 g/m for each layer.

The same resin may be used for the successive layers, otherwise different types of resins may be used for one or more of the continuous layers to be formed.

The multilayer configuration so obtained has well-defined purposes, which will be better explained below with reference, by way of example, to a three-layer deposition. The first layer acts as an "adhesive" between the coat deposited by grouting on the microfibrous matrix and the next layer, generally referred to as "intermediate layer". Then, the intermediate layer is associated with the third layer which, according to the particular embodiment as described herein, acts as a base for the subsequent surface treatments required to obtain the technical resistance, the aesthetic effect and/or the feel required in the final product.

Obviously, if the deposition includes a greater number of layers, the aforementioned "intermediate layer" may comprise multiple successive layers, and the third layer may also comprise multiple successive layers.

This will be recalled below through the next steps of the process.

It shall be noted that, according to a preferred and advantageous embodiment, the aforementioned spray deposition step is carried out in a starting condition in which:

- said surface of said microfibrous non-woven matrix has been grouted and - said grouted surface has not been dried yet.

Preferably, the aforementioned step of spray deposition of resin is carried out in a condition in which said surface of said microfibrous non- woven matrix has been grouted and is at a temperature ranging from 5 to 51 °C.

Preferably, the aforementioned step of spray deposition of resin is carried out after said grouting step, and before drying the grouting layer, i.e. with the grouting layer still wet. This will provide optimized adhesion of the spray-deposited resin on the grouted surface.

As mentioned above, the adhesion between the layers so formed and those that come next may be based on affinity or on the use of additives having an adhesive power.

Then, the process will continue with a hot embossing step, which involves partial melting of the fibers of the matrix, for permanent deformation of said fibers of said matrix. This will impress a permanent pattern of an embossed design on the aforementioned surface, by pressure. Thus, the composite resin material undergoes hot compression by rollers or plates having appropriate decorations.

Preferably, this hot embossing step is carried out at a temperature ranging from 130 to 170°C, and in any case at a temperature that can melt the fibers of the microfibrous non- woven matrix.

The temperature and pressure properties will obviously vary according to the materials that form the composite resin of the matrix or the aesthetic features to be impressed on the surface. Therefore, this processing step will define some of the aesthetic and tactile qualities of the finished product.

Once hot embossing is completed, the material so obtained preferably undergoes a drumming or tumbling step, to soften, smoothen and swell the microfibrous material for further treatment. This step is particularly recommended when specific softness and volume properties are required in the material being manufactured.

Finally, multiple continuous protective layers are deposited, to impart the desired mechanical properties and performances that are required to meet the specific requirements of target markets.

Preferably, these protective steps comprise resins, preferably made of water- or solvent- based polyurethane, applied with the micro droplet spray printing technology to form the various continuous layers to be formed, with a deposition amount ranging from 10 g/m to 25 g/m² for each of the continuous protective layer to be formed.

It shall be noted that the first protective layer applied to the surface after the hot embossing step is a layer of said polyurethane resins having adhesive properties, for improved adhesion of the subsequent continuous protective layers to the surface of the matrix. Therefore, the first protective layer so deposited has the purpose of enhancing adhesion of the subsequently deposited continuous protective layers to the surface.

The deposition technique that is used for the aforementioned continuous protective layers substantially coincides with the spray deposition technique as described above for the previous processing steps. The process of treatment of the original matrix can provide a product as shown in the figures. Particularly, Figure 1 shows the non-serial pattern of the decorative element, which makes the product visually comparable to natural leather.

Figure 2 is an enlarged view of Figure 1 and more clearly shows the roughness of the top surface.

Finally, Figures 3 and 4 highlight the multi-layer configuration of the resin deposited on the matrix. The darker surface layer proves that the last layers of protective resin have been deposited.

As partially mentioned above, the above discussed process has multiple variants. Certain particular embodiments thereof will be described below.

According to manufacturing requirements, as well as the physical and tactile properties of the material to be formed, the various successive resin layers, deposited by micro- droplet spray printing to form continuous layers as described above, may be obtained from the same material or from different materials, such that a continuous multi-layer arrangement of materials is formed, ensuring various properties.

Likewise, the amounts of materials so deposited to form the finished product, will depend on the physical, especially mechanical properties to be obtained, such as particular resistances to wear-causing agents, such as bending, scratching, elongation, to special chemicals, or properties such as waterproofness, breathability, etc.

In view of achieving these purposes, the matrix may be also enriched with reinforcing fibers, using a resin with a binding action, such as a water- or solvent-based polyurethane resin and/or collagen fibers.

As a result, the intended object was fulfilled, with the provision of a process of treating a microfibrous non- woven matrix that can provide a material whose exterior appearance is wholly comparable to leather; i.e. having all the desired inherent characteristics, a pleasant feel and all leather-like aspects.

Other advantages may be recognized by the skilled person in the foregoing description. Also, it should be understood that while the process has been described in accordance with a preferred embodiment, a number of variants may be envisaged without departure from the scope of the invention, as defined by the following claims.

Thus, for example, the coating step may be repeated a number of times other than that described above, according to the desired physical properties.

Claims

1. A process of treating a resin- impregnated microfibrous non- woven matrix, characterized in that it includes the following treatment steps:

A) providing a microfibrous non-woven matrix having a top surface to be treated;

B) preparing said top surface of said matrix by hot calendering and/or buffing;

C) grouting said matrix by depositing and distributing a base resin coat thereon;

D) performing a micro-droplet spray deposition of one or more resins, a hot drying step being carried out on said matrix between the deposition of one layer and the deposition of the next layer, preferably an oven-drying step at a temperature ranging from 80°C to 150°C, more preferably at a temperature ranging from 90°C to 110°C;

E) after said spray deposition step D) hot embossing the surface of said matrix, said embossing step being carried out by partial melting of the fibers of said matrix, to cause a permanent deformation in said fibers of said matrix;

F) performing a micro-droplet spray deposition to form one or more continuous protective layers of one or more resins.

2. A process of treating a microfibrous non-woven matrix as claimed in claim 1 wherein, after said step B), a smoothing resin is deposited to reduce surface porosity.

3. A process of treating a microfibrous non- woven matrix as claimed in claim 1 or 2 wherein, after said hot embossing step E), a material softening step is provided, preferably by drumming or tumbling.

4. A process of treating a microfibrous non-woven matrix as claimed in any of claims 1 to 3, wherein said resins deposited into intermediate layers have double-sided adhesive properties, the adhesion between layers being obtained by affinity or through additives.

5. A process of treating a microfibrous non-woven matrix for use in lining surfaces as claimed in any of claims 1 to 4, wherein said grouting step C) is carried out by a printing machine in which said microfibrous matrix is moved, said machine further having resin distribution cylinders that rotate in a direction opposite to the direction of movement of the matrix.

6. A process of treating a microfibrous non- woven matrix for use in lining surfaces as claimed in any of claims 1 to 4, wherein:

- said surface to be grouted is fed in a preset direction of feed and

- said grouting step C) is carried out using a counter-rotating grouting roller that contacts said surface to be grouted with a lateral surface portion whose peripheral tangential velocity is opposite to the direction of speed of the surface to be grouted.

7. A process of treating a microfibrous non-woven matrix for use in lining surfaces as claimed in claim 5 or 6 wherein, during said grouting step C) an amount or resin ranging from 20 to 150 g/m², more preferably from 30 to 50 g/m² is deposited on said top surface.

8. A process of treating a microfibrous non- woven matrix for use in lining surfaces as claimed in any of claims 1 to 7, wherein said material that has undergone the grouting process step C) undergoes a buffing step before said spray deposition step D).

9. A process of treating a microfibrous non-woven matrix for use in lining surfaces as claimed in any of claims 1 to 8 wherein, during said deposition process steps D) and F), an amount of resin ranging from 2 to 50 g/m , preferably from 10 to 20 g/m is sprayed in each step.

10. A process of treating a microfibrous non-woven matrix for use in lining surfaces as claimed in any of the preceding claims, wherein said resins are a water-based polyurethane resin or a solvent-based polyurethane resin.

11. A process of treating a microfibrous non-woven matrix for use in lining surfaces as claimed in any of claims 1 to 10, wherein said microfibrous material is polyamide.

12. A process of treating a microfibrous non-woven matrix for use in lining surfaces as claimed in any of claims 1 to 11, wherein said hot embossing step E) is carried out at a temperature ranging from 130 to 170°C, and in any case at a temperature that can melt the fibers of the microfibrous non- woven matrix.

13. A process of treating a microfibrous non-woven matrix for use in lining surfaces as claimed in any of claims 1 to 12 wherein said spray deposition step D) is carried out in a condition in which said surface of said microfibrous non-woven matrix has been grouted according to said step C), before said step of drying said grouted surface.

14. A process of treating a microfibrous non-woven matrix for use in lining surfaces as claimed in any of claims 1 to 13 wherein said spray deposition step D) is carried out in a condition in which said surface of said microfibrous non-woven matrix has been grouted according to said step C), and at a temperature ranging from 5 to 51°C.

15. A process of treating a microfibrous non-woven matrix for use in lining surfaces as claimed in any of claims 1 to 14, wherein said microfibrous non- woven matrix is not microporous.

16. A use of microfibrous non-woven polyamide material as a microfibrous non- woven matrix in a process as claimed in any of claims 1 to 15.