WO2018122718A1

WO2018122718A1 - Knitted non-woven textile with expanded microspheres and method for the production thereof

Info

Publication number: WO2018122718A1
Application number: PCT/IB2017/058370
Authority: WO
Inventors: Enrique Alejandro MORENO MUÑETONES
Original assignee: Moreno Munetones Enrique Alejandro
Priority date: 2016-12-26
Filing date: 2017-12-22
Publication date: 2018-07-05
Also published as: CO2016005772A1

Abstract

The invention relates to a knitted non-woven textile, and to a method for producing said textile. Said knitted non-woven textile comprises a non-woven textile made of synthetic fibres and synthetic filaments knitted into said non-woven textile. It also comprises expandable microspheres integrated into said non-woven textile and holes arranged over the entire surface of the non-woven textile. The method comprises four main steps in which: the non-woven textile is knitted with the synthetic filaments, the knitted non-woven textile is then impregnated in a solution, it is subjected to heating in order to cure the formulation and expand the microspheres, and finally holes are made in the knitted non-woven textile.

Description

NON-FABRICED TEXTILE WITH WOVEN EXPANDED MICRO-SPHERES AND MANUFACTURING METHOD

Field of the Invention

The present invention pertains to the field of laminated composite materials, specifically that of core or reinforcing materials with expandable microspheres. Description of the state of the art

The prior art discloses core or reinforcement materials such as those disclosed in US4818583 and US6607997B1. Document US4818583 discloses a nonwoven fibrous network with microspheres which are similarly arranged in "islands", separated from each other by channels containing less than 5% by volume of microspheres. Also, the document discloses that the non-woven fibrous web can have holes of approximately 1.5mm apart from each other between 5mm and 15mm. On the other hand, the document discloses a punctured fibrous network (needle punched, in English) between 2.5mm and 4.2mm thick. In one embodiment of the invention, the fibrous web is made up of 85% by weight of 5.0Tex / 50mm polyester fibers and 15% of meltable fibers. A foamed composition is applied to the punched web. The document discloses that the fibrous network can be impregnated with a foam binder.

On the other hand, document US6607997B 1 discloses a core material for use in the production of fiber reinforced plastic materials, particularly for application in closed mold systems. The document discloses a core type material with expandable microspheres arranged in the laminar element with spongy structure. The sheet element has at least 20% by weight of fibers and up to 80% by weight of binder material and expandable microspheres. The sheet element can be formed of glass fibers, polyester, polyester-polyethylene bi-components, and combinations thereof. The binder may include acidic groups, carboxylating agents, water, surfactants, stabilizers, fillers and thickeners.

Although the core or reinforcing materials disclosed in the previous documents provide a greater thickness and therefore a greater moment of inertia of the final laminates, said materials do not provide mechanical properties that increase the tensile, flexural and compression resistance of the final product. . Another disadvantage of these developments is in the manufacture of products with curved regions, as their fibers break when bent, for this reason it is difficult to produce cylindrical, spherical or narrow curved parts.

It is also common to find in areas manufactured by the Spray-Up and Hand Lay-Up methods areas of the laminate with less mechanical strength and rigidity. This is because the core material tends to break down in areas impregnated with excess resin, such as edges and cavities, when pressure is applied with the roller during surface settlement.

Brief description of the figures FIG. l corresponds to a detailed view of a modality of knitted nonwoven textile.

FIG. 2 corresponds to a modality of an expandable sphere before and after the expansion.

FIG. 3 corresponds to a plate of laminated material with layers of a knitted non-woven textile pattern oriented quasi-isotopically.

FIG. 4 represents a cross-section of a pipe constructed with a knitted nonwoven fabric embodiment.

FIG. 5 illustrates the process of manufacturing a pipe with a modality of knitted nonwoven textile. FIG. 6 is a schematic of a method by which a nonwoven textile is manufactured.

FIG. 7 is a schematic of an embodiment of the method by which knitted nonwoven fabric is manufactured.

Brief Description of the Invention

The present invention corresponds to a knitted nonwoven textile and a method for manufacturing it.

Knitted nonwoven fabric comprises between 60% w / w and 80% w / w of a nonwoven textile made of synthetic fibers, and between 3% w / w and 6% w / w of synthetic filaments knitted in the nonwoven fabric. In addition, knitted nonwoven textile includes between 1% w / w and 30% w / w of expandable microspheres; and it has perforations arranged along the nonwoven textile. Knitted nonwoven textile has a density between 100g / m ² ; and 200g / m ² ; and a thickness between 2mm and 5mm.

The method for manufacturing said knitted nonwoven textile comprises a first stage where a nonwoven textile with synthetic filaments is knitted; a second stage, where the nonwoven textile of the first stage is impregnated with a solution containing expandable microspheres; a third stage where the nonwoven textile of the stage is subjected to heating and a final stage where the nonwoven textile of the previous stage is perforated. Detailed description of the invention

The use of composite materials is widespread in sectors such as automotive, electronics, energy, the water industry or construction to name just a few.

The core or reinforcement materials are used to provide thickness to the fiber laminates, in order to reduce the weight, increase the moment of inertia and therefore the stiffness of the final product. Currently, the core or reinforcement materials on the market have limitations in the manufacture of spherical and cylindrical parts, and large surface flat parts. This is because they have low mechanical properties, such as flexural strength.

On the contrary, the knitted nonwoven fabric of the present invention offers greater mechanical strength, stiffness and durability compared to traditional core or reinforcement materials, such as balsa wood, flexible materials with expandable microspheres (3) (such as mentioned in the description of the state of the art) and polyurethane foams; This development allows greater maneuverability during the rolling process due to the inherent flexibility of the material.

The knitted nonwoven fabric of the present invention can be used in the manufacture of wind turbines, these elements support loads, produced by the wind, which generate torsional and bending stresses in the material. It is also ideal for the manufacture of pipes, tanks, pressure vessels, panels, cylindrical and spherical parts, and as a core or reinforcing material for acoustic and thermal insulation. On the other hand, the knitted nonwoven fabric of the present invention can be used in combination with plastic resins such as polyester, vinyl ester, epoxy or acrylic reinforced with natural, glass, ceramic, metal, or synthetic fibers such as acrylic, polyethylene , polyester, aramid, carbon or polypropylene. The present invention relates to a knitted and expanded nonwoven and a method for manufacturing it.

Referring to FIG. l, the knitted nonwoven fabric of the present invention comprises between 60% w / w and 80% w / w of a nonwoven textile (1) made of synthetic fibers; between 3% w / w and 6% w / w synthetic filaments (2) knitted in the nonwoven fabric (1); between 1% w / w and 30% w / w of expandable microspheres (3); and perforations (4) arranged along the nonwoven textile (1). Knitted nonwoven textile has a density between 70g / m ² and 450g / m ² ; and a thickness between lmm and 10mm. A non-woven fabric (non-woven fabric in English) consists of fibers that have been joined together by mechanical, chemical or physical means, regardless of the traditional method of producing textiles, where the fibers are spun and woven to form the fabric. This represents an advantage in the production of nonwoven fabrics, since the production speed of the final nonwoven fabric is much higher than that of a woven fabric. All the yarn preparation steps are eliminated, and the production of the fabric itself is faster than conventional methods. For example, to produce 500,000 meters of woven textile requires two months of yarn preparation, three months of knitting on 50 looms and one month for finishing and inspection; On the other hand, for the same amount of a nonwoven textile, the term is two months.

Not only is the nonwoven textile production rate higher compared to the others, it is also well known that the process requires less labor as opposed to fabrics. Nonwoven textiles are characterized by their versatility, since their characteristics can be established according to need, therefore, it is possible to obtain absorbent or waterproof, elastic or rigid, soft or rough, fire resistant, sterilized, non-woven fabrics. high thickness for cushioning or thin for clothing. Each of its properties are adapted and combined for specific uses, balancing according to the cost and the shelf life of the product.

For the understanding of the present invention, "synthetic fibers" will be defined as those textile fibers manufactured from natural raw material or chemical synthesis product raw material. An example of this are cellulosic regenerated fibers, such as rayon, acetate and triacetate; polymer fibers such as polyamide, aramid, spandex, polyester, polypropylene, or acrylics, protein, rubber, metal or mineral fibers such as fiberglass. The synthetic fibers that make up the nonwoven textile can be selected from the group consisting of mineral, glass, ceramic, metallic, or synthetic fibers such as acrylic, polyethylene, polyester, aramid, carbon, polypropylene or combinations of the above. In one embodiment of the invention, synthetic fibers are selected from glass fibers, polyester fibers, bicomponent polyester fibers, polyethylene and combinations of the foregoing.

Synthetic fibers have great advantages over other types of mineral and natural fibers. For example, synthetic fibers offer high resistance to moisture, UV and UVA, greater resistance to stress and acid and alkaline media, high durability, dimensional stability and the possibility of designing features such as, cross section, diameter and length according to the desired final product. Additionally, with the development of bicomponent fibers, new possibilities have been added when manufacturing nonwovens with synthetic fibers. An example of this is the "cover-core" or "side-side" type fibers where two polymers are combined with different melting points, in order to join the fibers thermally without resorting to mechanical actions. Some commonly used polymer combinations are: polyester cover (melting point: 250 ° C) with copolyester core (melting point: between 110 ° C to 220 ° C), polyester cover (melting point: 250 ° C ) with polyethylene core (melting point: 130 ° C), polypropylene shell (melting point: 175 ° C) with polyethylene core (melting point: 130 ° C).

In a preferred embodiment of the invention, the synthetic fibers of the nonwoven textile are polyester fibers. These represent a better option compared to other fibers such as polyamides and aramids that are rarely used in the reinforced plastics industry because because these materials are poorly compatible with polyester resins (adhesion), they shear themselves and have low resistance to UV rays and somehow absorb water; if compared with polyester. Similarly, polyester fibers have greater advantages than polypropylene fibers that have a very low melting point, or polyethylene fibers that on the other hand have a melting point that is too high and are more rigid.

Finally, glass fibers are more abrasive than polyester fibers and this results in greater wear on the machinery that processes it. In addition to presenting risks to the health of the people involved in their processing.

Knitted nonwoven fabric comprises between 60% w / w and 80% w / w of a nonwoven textile (1) made of synthetic fibers. If this interval is exceeded and the knitted nonwoven fabric includes more fiber, there will be less amount of expandable microspheres (3) and the expansion will not be significant, therefore, volume is lost and more resin will have to be used, in this way Knitted non-woven textile would lose mechanical properties as stiffener, as it will be more brittle, fragile and heavy.

In the opposite case, where knitted nonwoven textile does not reach 60% w / w of nonwoven textile (1) made of synthetic fibers, the mechanical properties would be affected because there will not be enough base material to house the remaining components of knitted nonwoven textile, decreasing volume, increasing density and weight, and therefore increasing the demand for resin. For the understanding of the present invention, "synthetic filaments" will be defined as those textile filaments manufactured from natural raw material or chemical synthesis product raw material. Examples of this are filaments made of regenerated cellulosic fibers, such as rayon, acetate and triacetate; polymer fibers such as polyamide, spandex, polyester, or acrylics, protein, rubber, metal or mineral fibers such as glass fiber.

Knitted or sewn filaments in a textile can have different functional purposes. Knitting a nonwoven textile with filaments improves its properties mechanical, for example, a greater tensile strength in the direction of the filaments, a more uniform surface is achieved and the possibility of the textile falling apart during handling is reduced. The present invention achieves greater mechanical strength compared to that of traditional core or reinforcement materials thanks to the inclusion of synthetic filaments (2) sewn along the knitted nonwoven fabric. The tensile strength of knitted nonwoven textile is about seven times greater than nonwoven nonwoven textile, it also has greater resistance to bending and stiffness of the final product, even in elements such as flat plates of large surfaces.

The inclusion of synthetic filaments (2) makes it possible to manufacture products with curved regions, because the textile has high flexural strength, and does not break or undo when folded and pressed. This property allows the construction of parts such as gas tanks, pipes and all kinds of spherical and curved elements, thanks to the fact that the non-woven textile does not melt during the manufacture of the laminate, and thus the final product retains similar properties throughout its surface. This represents a great advantage over core type materials or traditional reinforcements such as balsa wood, with which it is impossible to manufacture cylindrical or spherical pieces, as their fibers break when bent

The knitted nonwoven fabric comprises between 3% w / w and 6% w / w synthetic filaments (2) knitted in the nonwoven fabric (1); in case this interval is exceeded, the flexibility of knitted nonwoven textile would decrease, the material would become more expensive and the probability that, during the perforation process, in which the perforations (4) are generated, the filaments will be broken synthetic (2), because they could not move laterally when the needles touch them. In the opposite case, where 3% w / w of synthetic filaments is not reached (2), the mechanical strength would decrease and knitted non-woven textile would have the same properties as the non-knitted textile.

In one embodiment of the invention, the synthetic filaments (2) have a diameter between 60tex and 220tex and a distance between 3mm and 4mm is separated from each other within the nonwoven fabric. In a preferred embodiment of the invention, the synthetic filaments (2) have an approximate diameter of 150tex and reach between 3% w / w and 5% w / w of the knitted nonwoven textile; the filaments are separated from each other within the nonwoven textile by a distance of 3.62mm; This distance corresponds to a number seven gauge (gauge 7) of a knitting machine.

In one embodiment of the invention, the synthetic filaments (2) can be polymeric (eg polyester, polyethylene, ethylene polytetrafluoride (PTFE), polyolefins), glass, carbon, aramid, and combinations of the above.

In one embodiment of the invention, the synthetic filaments (2) are glass filaments coated with ethylene polytetrafluoride. The PTFE coating protects the needles used to knit the filament, and the needles used to generate the perforations (4), from abrasion that would generate direct contact of the needles with the glass filament.

In a preferred embodiment of the invention, the synthetic filaments (2) are polyester. The advantages of using this material are among others: total compatibility between the materials of the invention (non-woven textile (1) made of synthetic fibers, synthetic filaments (2), formulation with expandable microspheres (3) and resin used for manufacture the compound), which ensures good adhesion, and approximately 5% w / w reduction in the amount of resin needed to form a composite. In addition, when using a knitted nonwoven fabric composed of synthetic polyester fibers, and synthetic filaments (2) of polyester, as a core or reinforcement material in laminates that include polyester resins (eg isophthalic, terephthalic, orthophthalic), the Chemical adhesion between the resin and the knitted nonwoven textile for being the three polyester elements (the nonwoven, the filament and the polyester resin).

During the manufacturing process of the composite material, these two parts, that is, the knitted nonwoven textile and the resin become a single element. The above prevents the formation of defects in the final laminate, such as bubbles and areas of low impregnation, which ensures optimum adhesion of the compound.

Compared to the good adhesion of polyester, aramid presents problems of adhesion between layers of the same material. A common solution to the problem is the addition of a fiberglass mantle between aramid layers. Because both materials have a similar strain elongation rate (3%), this makes them compatible, however, the laminate increases considerably in weight. Polyester has a specific gravity of 1.38gr / cm ³ , lower than polyparaphenylene terephthalamide (1.44gr / cm ³ ), carbon (1.58gr / cm ³ ) and glass fiber (2.2gr / cm ³ ). Raft wood having a lower specific weight than polyester, is only useful for manufacturing flat pieces and with minimum degrees of curvature. On the other hand, the fiberglass mantle, in addition to being up to four times heavier than the knitted nonwoven fabric of the present invention, presents dangers for human health during handling. The effects of fiberglass exposure are varied and depend on the size of the fibers in question. There may be irritation of the throat, eyes and skin, irritation of sweat glands, pulmonary and neurological disorders. It is also possible that glass wool has carcinogenic effects.

The most commonly used types of fiberglass are mainly class E glass (alumino-borosilicate glass with less than 1% w / w alkaline oxides, mainly for glass fiber reinforced plastic). Also used: class A glass (calcium glass with little or no boron oxide), glass E-CR class (with alumino-calcium silicate, with less than 1% w / w alkaline oxides, has high resistance to acids), class C glass (sodium-calcium glass with high boron oxide content, which is used, for example, for staple fiberglass), class D glass (borosilicate glass with high dielectric constant), class R glass (aluminosilicate glass without MgO and CaO for high mechanical requirements), and class S glass (aluminosilicate glass without CaO, but with high MgO content for high strength).

Carbon fiber has little impact resistance and it is for this reason that it is used in combination with fiberglass mantles. Again, the problem of an increase arises substantial of the final weight of the compound. Carbon fiber has very low resistance to friction and is therefore not used as a coating material. Loose and floating carbon fibers in the air are also dangerous for human health. Aramid or carbon fiber fabrics are flexible, but should not be folded. This generates friction that deteriorates the fibers of the fabric and as a consequence the material loses resistance. In this way molding problems occur, specifically in the mold joints. Portal motif requires an extra reinforcement material such as a fiberglass mantle that causes the compound to increase in weight.

Another advantage of the use of polyester is its color, the polyester fibers can be matt white, semi matt and glossy, it is also in an almost transparent tone, which makes it an ideal material for the manufacture of translucent and transparent parts. The aramid yellow and carbon fiber black color limits its applications because they are not translucent materials when impregnated with the resin, which reduces its versatility. The polyester being white radiates UV rays and is highly resistant to them, unlike aramids that are sensitive to sunlight and to environments with high UV dissipation. Polyester has excellent resistance to acids (sulfuric acid, acid hydrochloric, etc.); oxidants (chromic acid and nitric acid, etc.) and in special presentations it has resistance to the bases. Aramids have little resistance to strong acids, bases and some oxidants such as sodium hypochlorite. Polyester is an inert material, does not rot, does not give fungi and is not attacked by bacteria or algae when in contact with fresh water or seawater. It is a material that is easy to handle, easy to cut, mold and handle especially at the time of molding. On the contrary, aramids are difficult to cut both in their state of reinforcement material and in the final laminate, and the tools for cutting or polishing are limited, such as those composed of silicon carbide. On the other hand, fiber and Aramid laminates cannot be sanded as the fabric tends to produce lint, this due to its high degree of abrasiveness.

The use of aramid is widespread in applications where high impact resistance is required, such as ballistic armor elements, skate boarding boards, aeronautical and naval construction, and fire protection.

On the other hand, carbon fiber is especially used in applications that require a significant decrease in product weight as in the automotive, aeronautical, bicycle construction, etc.

It is sought that the core or reinforcing materials contribute a greater volume to the compound without increasing the weight of the compound. For this, and to increase the cohesion between the non-woven fibers, in the present invention, the knitted nonwoven fabric is impregnated in a formulation that includes the following components listed below:

Table 1. Composition of the formulation

Water makes up most of the formulation and is used as a vehicle for the other components. However, the final knitted nonwoven fabric has a minimum amount of water (less than 0.05% by weight), since water is a harmful component for the quality of resin laminates. This is because, during the resin curing process, an exothermic reaction is generated that produces enough heat to evaporate the water present in the laminate; When the water evaporates, defects are generated, mainly bubbles.

The resin gives the knitted nonwoven fabric greater stiffness and adhesion between the fibers, allowing the textile not to be undone easily and its transport and handling is easier. Said resin can be selected from the group consisting of water-based acrylic resins and styrene acrylic resins.

In a preferred embodiment of the invention, water-based acrylic resin is used, because it is highly compatible with polyester fibers.

The nonwoven textile is impregnated with the previous formulation with the main objective of introducing expandable microspheres (3) into the nonwoven textile. The expandable microspheres (3) play an important role because they increase the volume of knitted nonwoven fabric. This increase in volume represents a low increase in weight. The low density (from 25 kg / m ³ ) of the expandable microspheres (3) makes it possible to manufacture large pieces saving up to 35% in weight; without the composite material losing mechanical or chemical resistance.

In addition, the expandable microspheres (3) are resilient and for this reason have a high elasticity index. When expanded they withstand high pressures, but if the pressure is removed, the expandable microspheres (3) return to their original size. When the expandable microspheres (3) are saturated with resin, they acquire greater mechanical strength by gaining rigidity.

On the other hand, when using the expandable microspheres (3), there is a significant reduction of resin used because the expandable microspheres (3) occupy the space that the resin would occupy in a composite material. Another advantage is that when the microspheres are incorporated in the knitted nonwoven fabric, they have good resistance to high temperatures (<230 ° C). After expansion, the expandable microspheres (3) reach a density of 25kg / m ³ , 0, 1 μιη thick and 40μιη in diameter, in their unexpanded state their typical density value is 1000kg / m ³ , 2μιη thick and 12μιη in diameter. The expandable microspheres (3) usually consist of a composite external structure that can be made of glass, ceramic or polymer.

The formulation used in the present invention is comprised of between 5% w / w and 40% w / w of expandable microspheres (3).

Referring to FIG. 2, in one embodiment of the invention the expandable microspheres (3) have a synthetic resin surface (5) such as polystyrene, styrene copolymers, polyvinyl chloride, vinyl chloride copolymers, chloride copolymers Vinylidene and the like. Also, the expandable microspheres (3) incorporate a chemical or physical expansion agent (6) that can be azodicarbonamide, isobutane, or refrigerants composed of chlorofluorocarbons. After the expansion, its expanded surface (7) decreases its thickness and increases its area, and the expansion agent (6) reacts, increasing the pressure and constituting the interior (8) of the expandable microsphere (3).

In a preferred embodiment the expandable microspheres (3) are thermoplastic, they have a copolymer exterior of: vinylidene or acrylonitrile chloride and methyl methacrylate; and an isobutane interior. In one embodiment of the invention the percentage of expandable microspheres (3) varies between 5% w / w and 30% w / w because a smaller percentage would not achieve the desired volume increase and a larger percentage of said expandable microspheres (3) it would not be able to contain itself in the non-woven textile (1) Various chemical reactions that are generated in aqueous solutions require that the pH of the system be kept constant, to prevent other unwanted reactions from occurring. For this reason a ph balancer is added to the formulation that is selected from the group consisting of ammonia, monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), sodium carbonate, sodium bicarbonate, calcium and combinations thereof. The group consisting of sodium carbonate, sodium bicarbonate and calcium must be diluted in water. To increase the speed of the chemical reaction undergone by the formulation, a catalyst is added, which can be, for example, ammonium sulfate.

To increase the viscosity and stability of the formulation and facilitate the formation of suspensions without altering its properties, a thickener is added which can be, for example, polymers in aqueous dispersion of acrylic esters.

So that the expandable microspheres (3) and other particles of the formulation are distributed in a homogeneous manner and are arranged equally in the textile when it is impregnated in the formulation, a dispersing additive is added thereto which can be, for example , a mixture of special non-ionic alcohols.

During the preparation of the formulation and its application in knitted non-woven textile the presence of bubbles or foam is undesirable. Since impregnation problems can be caused mainly because where there are bubbles there is trapped air and once the bubble bursts the knitted non-woven fabric will not be impregnated by the formulation. In addition, bubbles can cause spillage losses, reduce the capacity of open systems, alter the protection and hygiene conditions of work, etc. For this reason, an antifoam is added to said formulation which can be, for example, a non-ionic material based on modified silicone.

Some fibers used for the manufacture of the nonwoven textile (1) have low absorption, for this reason a wetting agent is used so that the resin adheres to the fibers, said wetting agent can be, for example, sodium xylenesulfonate or an alkylphenol .

In one embodiment of the invention (not illustrated), the knitted nonwoven fabric impregnated with the formulation described above passes through the middle of two or more foulard rollers where the excess formulation is removed and engraved on one or both sides a pattern formed by interlocking reliefs and channels. This pattern favors the flow of resin on the surface of the knitted nonwoven fabric during the manufacture of the laminate and increases the adhesion between layers thereof. After impregnation with the formulation described above, the knitted nonwoven fabric is brought to a heating process where the expandable microspheres (3) expand and the acrylic resin is cured. Subsequently, the knitted nonwoven fabric goes through a perforation process where, by means of preheated needles at a temperature between 138 ° C and 148 ° C, perforations (4) are made in the knitted nonwoven textile. Said perforations (4) are created when the needle moves the material sideways through the knitted nonwoven fabric from one side to the other. These perforations (4) increase the adhesion between the layers of a laminate made with the knitted nonwoven fabric of the present invention. Because "I" shaped connections are created between the resin zones, both in flat elements and in cylindrical or spherical elements.

In one embodiment of the invention the number of perforations (4) is between 6298 and 6554 perforations / m ² . In one embodiment of the invention the number of perforations (4) is approximately 6426 perforations / m ² .

After the perforation process, the knitted nonwoven fabric is ready to be used as a core material of a laminate which can be made using resins selected from the group consisting of orthophthalic polyester resin, isophthalic polyester resin, terephthalic polyester resin, chlorenic polyester resin, brominated vinyl ester epoxy resin based on bisphenol-A, vinyl ester-based Novolac epoxy resin, amine-cured bisphenol-A epoxy resin, anhydrous cured bisphenol-A epoxy resin, bisphenol resin -A brominated fumarate, divinylene oxide resin, phenolic resins, polyethylene resin, PA 66 saturated water resin, PA 66 Dry resin, and combinations thereof. In a preferred embodiment, knitted nonwoven textile is used in combination with polyester resins, because this increases component compatibility, increasing adhesion and final product quality. Referring to FIG. 3, several layers, quasi-isotopically oriented, of the knitted nonwoven fabric of the present invention are used for the manufacture of a composite material. For the understanding of the present invention it is determined that the orientation is given by the direction of the synthetic filaments (2) in the knitted nonwoven fabric. Where the first layer (12) has a 0 ^or orientation, the second layer (11) has a 45 ° orientation, the third layer (10) has a 90 ° orientation and the fourth layer (9) has an orientation to 135 °. A quasi isotopic compound made with the knitted nonwoven fabric of the invention, of lm2, can have a weight between 9000g / m ² and 11000g / m ² . Where approximately 5% w / w of the compound is the knitted nonwoven fabric and the remaining 95% w / w is the resin. This means that with only 5% knitted nonwoven textile, the compound is no longer brittle and on the contrary acquires unique mechanical and chemical properties at very low weight.

This increases the stiffness and resistance to bending and tension of the final product, making it possible to manufacture flat pieces with large surfaces that resist bending and cylindrical elements such as tanks or pipes capable of withstanding high pressures.

Referring to FIG. 4 and FIG. 5, in one embodiment of the invention, a pipe is made of knitted nonwoven fabric. Initially a release agent (13) is applied on a mandrel where the pipe will be manufactured, said release agent (13) allows the pipe to easily exit the mandrel at the end of its conformation. This release agent is selected from the group consisting of vegetable oils such as coconut oil, mineral oils, long chain saturated hydrocarbons, polyvinyl alcohol and combinations thereof. Subsequently, an inner layer of resin (14) is applied, and a knitted nonwoven textile belt (15) is wound, forming a random arrangement that ensures that the layers of the pipe have a different direction and that their perforations (4 ) I dont know face. This creates joints in the form of "I" (16) where the resin (14) is inserted, ensuring excellent adhesion between layers and greater rigidity.

In this way it is feasible to manufacture different types of pipes where the knitted nonwoven fabric of the invention is used in combination with other materials, for example: glass fiber, carbon fiber, aramid, epoxy resin, saturated polyester resin, etc, according to its use and manufacturing process.

The present invention includes a method for manufacturing a knitted nonwoven fabric comprising the following steps:

a) knit a non-woven textile (1) with synthetic filaments (2);

b) impregnate the nonwoven fabric (1) with the formulation (described above) containing expandable microspheres (3); Y,

c) heat the nonwoven fabric (1) of stage (b) to a temperature between 120 ° C and 140 ° C and d) perforate the nonwoven fabric of stage c).

In an embodiment of the present invention and prior to the process described above, a nonwoven fabric must be available. A manufacturing process of a non-woven textile is indicated in FIG. 6 and after the opening of a pressed fiber (bale), the fiber passes through an opener (17) to individualize the fibers. The fibers then pass through a loader in order to transport the loose fibers in a controlled manner by means of a photo cell to a card (18) that guides and combs the fibers forming a veil. This veil passes through a machine where the direction of the veil is changed to 90 ° and the thickness is given to the fabric (machine called in English Cross lapper).

The thickness can vary between lmm and 10mm. In one embodiment of the invention said thickness can be 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm or 10mm. In one embodiment of the invention the thickness is between 2mm and 4mm. In one embodiment of the invention the thickness is 2.5mm. From the cross-lapper comes a napa (19), that is to say several layers of veils (according to the thickness of the fabric) that passes through a cold calender (20) in order to lower the thickness. The resulting napa passes through a pre punching machine (not illustrated) and then through a punching machine (21) that confers mechanical strength to the nappa. This is achieved through a series of needles that reorient the fibers vertically. After this the raw cloth is rolled in a cylinder forming the raw roll of nonwoven textile (22).

Referring to FIG. 7, in one embodiment of the present invention, the raw nonwoven textile roll (22) goes through the knitting process (23), where synthetic filaments (2) are sewn, in the longitudinal direction of the raw roll of nonwoven textile (22). In a preferred embodiment of the invention, knitting is performed with equipment using a seven gauge (gauge 7, in English) which sews the filaments with a distance of 3.62mm between them. Referring to FIG. 7 in an embodiment of the present invention and after the knitting process is finished, the knitted nonwoven roll is unwound to pass through the impregnation process (24) where it is impregnated with the formulation consisting of water , acrylic resin, expandable microspheres (3) and additives. Subsequently, the excess formulation is removed by means of two Foulard-type cylinders located in parallel that rotate in opposite directions and generate pressure on the knitted nonwoven fabric, removing the excess formulation contained in the knitted nonwoven textile. In this way and with the knitted nonwoven fabric still wet, the knitted nonwoven fabric is heated within a temperature range of 120 ° C to 140 ° C. In a preferred embodiment of the invention the temperature varies between 120 ° C and 130 ° C. This heating process can be carried out in an oven (25) or in a dryer of steam-heated cylinders, where the resin of the formulation is cured and the expandable microspheres (3) expand, thus the fabric comes out dry and is rolled again in a winder (26).

The knitted non-woven textile must have a thickness of less than 10mm, since a thicker thickness would not allow the expandable microspheres (3) inside the textile to react. Said thickness is controlled by the pressure applied to the foulard cylinders to remove excess formulation. In one embodiment of the invention the cylinders that remove the excess formulation apply a pressure between 137.9kPa (20psi) and 344.7kPa (50psi) on the knitted nonwoven fabric. In a preferred embodiment of the invention cylinders that remove excess formulation apply a pressure of 275.8kPa (40psi) on knitted nonwoven fabric

Referring to FIG. 7, the last step of the method of the present invention carried out with knitted nonwoven fabric is perforation (27). After the curing process the fabric is unwound again to pass through a perforator (28), this in order to make perforations (4) to the fabric, which provide the final product with greater resistance and adhesion between the layers of the laminate, due to to that the resin of the compound penetrates through these perforations (4) and creates a type of connection between the layers of resin that ensures the union.

The perforations (4) are generated by means of hot needles that seal the holes preventing them from closing. Preferably, said needles are blunt tip which allows both the nonwoven and the filaments therein to move instead of breaking.

It is important to consider that the number of perforations (4) and the distance between them in the knitted nonwoven fabric, also depends on the tension of the knitted nonwoven fabric with which the perforator (28) is fed, at higher tension plus perforations ( 4) and less stress less perforations (4).

In a preferred embodiment of the invention, the hot needles that pierce the knitted nonwoven fabric have a temperature of 140 ° C.

Example 1: Knitted nonwoven textile

A knitted nonwoven textile of the following characteristics was manufactured: • 80% w / w of nonwoven textile (1) made of polyester fibers, these fibers have between 1.5 and 15.0 denier; 3cm and 10cm long, and 70g / m ² and 150g / m ² density,

• 19% w / w formulation with water, water-based acrylic resin, expandable microspheres (3), ammonia as a pH balancer, ammonium sulfate as a catalyst, an aqueous dispersion polymer of acrylic esters as a thickener, a mixture of special alcohols non-ionic as dispersant, a non-ionic silicone-based material modified as antifoam and xylenesulfonate as a humectant,

• l% w / w polyester filaments of 150 tex; and nominal distance between the 3.62mm filaments,

• thickness of 2.5mm, and

• an average of 6426 perforations / m ^2.

Example 2: Panel

A laminated lm ² panel was designed and constructed with the knitted nonwoven fabric of Example 1; orthophthalic polyester resin, and glass fiber mat 450g / m ² polyester resin unsaturated. The ratio between resin and fiberglass is 1: 1 (for every kilogram of fiberglass one kilogram of resin is added).

A mold was taken from the panel which was previously waxed and eight layers of wax were applied and allowed to dry between each layer application.

The waxed mold was painted with gel coat and allowed to dry until it was tactose. The thickness of the gel coat was 12mills.

Then two layers of fiberglass mat were applied, then a layer of knitted nonwoven fabric of Example 1, and then two other layers of fiberglass mat. The process was by hand-lay up, and each of the mat layers with manual rollers were seated. Between each layer, the ortho-resin resin was applied by spraying, which is catalyzed at the time of spraying with methyl ethyl ketone peroxide (MEKP).

After setting the last layer, 12 hours were expected to unmold the panel.

Example 3: Quasi Isotropic Panel

Referring to FIG. 3, a lm ² panel with four layers of the knitted nonwoven fabric of Example 1 was manufactured by means of the hand lay-up method, where the first layer (12) has an orientation of 0 ^or , the second layer (11) has an orientation at 45 °, the third layer (10) has an orientation at 90 ° and the fourth layer (9) has an orientation at 135 °. 5 layers of orthodoxic polyester resin were applied.

Knitted non-woven textile has a weight of 122g / m ² which means a weight of 488g / m ² per four layers. The resin has a weight of 1800g / m ² which means a weight of 9000g / m ² . The total weight of the panel is 9488 g / m ² .

Example 4: Knitted nonwoven textile pipe Referring to FIG. 4 and FIG. 5, a pipe was manufactured by the following process:

A release agent layer (13) was applied on a mandrel like coconut oil, then a resin layer (14) was applied and a ribbon (15) of the knitted nonwoven fabric of example 1 was wound around the mandrel, on the textile a resin layer (14) was applied again and the tape (15) was returned on said layer creating a new sheet.

Said pipe was composed of polyester resin and knitted nonwoven textile tape of the present invention, with the following characteristics:

• angle of the lycopene: 15 °

• two layers with a thickness of: 2.5mm

• tape width: 13cm • resin impregnated with brush and hose

• diameter: 2 "3/4

• final thickness of the pipe 7mm

• unsaturated isophthalic polyester resin

MEK catalyst 2.5% w / w resin (porlOOgr resin 2.5gr catalyst).

Claims

A knitted nonwoven textile comprising:

a nonwoven textile (1) between 60% w / w and 80% w / w, the nonwoven textile (1) made of synthetic fibers;

synthetic filaments (2) knitted between 3% w / w and 6% w / w, synthetic filaments (2) are knitted in nonwoven textile (1);

expandable microspheres (3) between 1% w / w and 30% w / w, the expandable microspheres (3) are arranged in the nonwoven fabric (1); Y

perforations (4) arranged along the nonwoven textile (1);

where, knitted nonwoven textile has a density between 70g / m ² and

450g / m ² ; and a thickness between lmm and 10mm.

The nonwoven knitted fabric of claim 1, wherein the number of perforations (4) are between 6298 and 6554 perforations / m ^2.

The knitted nonwoven fabric of Claim 1, characterized in that the synthetic filaments (2) are between 60tex and 220tex, the synthetic filaments (2) are separated from each other within the nonwoven textile (1) by a distance between 3mm and 4mm .

The knitted nonwoven fabric of Claim 3, characterized in that the synthetic filaments (2) have 150tex; The nominal distance between the synthetic filaments (2) is 3.62mm.

The knitted nonwoven fabric of Claim 1, characterized in that the synthetic filaments (2) are selected from the group consisting of polymeric filaments (eg polyester, polyethylene, ethylene polytetrafluoride (PTFE), polyolefins), filaments of glass, carbon filaments, aramid filaments, and combinations of the above.

The knitted nonwoven fabric of Claim 1, characterized in that the synthetic fibers of the nonwoven fabric (1) are selected from the group consisting of fibers of glass, polyester fibers, bicomponent polyester and polyethylene fibers, and combinations of the above.

The knitted nonwoven fabric of Claim 1, characterized in that the synthetic fibers of the nonwoven fabric (1) and the synthetic filaments (2) are polyester.

The knitted nonwoven fabric of Claim 1, characterized in that the synthetic fibers of the nonwoven fabric (1) have between 1.5 and 15.0 denier; 3cm and 10cm long, and 70g / m ² and 150g / m ² density.

The knitted nonwoven fabric of Claim 1 comprises a pattern formed by interlocking reliefs and channels.

A method for manufacturing a knitted nonwoven fabric comprising the steps:

a) knit a non-woven textile (1) with synthetic filaments (2);

b) impregnate the non-woven textile (1) of step (a) in a formulation composed of:

c) heating the nonwoven fabric (1) of step (b) to a temperature between 120 ° C and 140 ° C; Y,

d) perforate the non-woven textile of stage (c)

11. The process of Claim 10 characterized in that in step b) the formulation is composed of:

Expandable microspheres Between 5% and 40%

PH balancer Between 0.5% and 2%

Catalyst Between 0.5% and 2%

Thickener Between 0, 1% and 2%

Dispersant Between 0, 1% and 2%

Antifoam Between 0, 1% and 2%

Moisturizer Between 0, 1% and 2%

12. The process of Claim 10, characterized in that between stage b) and stage c) there is a stage b ') in which the excess formulation of the nonwoven fabric (1) is removed by means of Foulard-type cylinders.

13. The process of Claim 10 characterized in that in step c) the nonwoven textile of a stage b) passes through hot cylinders.

14. The process of Claim 10 characterized in that in step d) the drilling is done by means of preheated hot needles at a temperature between 138 ° C and 148 ° C.