阅读说明：本技术 一种近似各向同性柔性复合材料及制备方法 (Near-isotropic flexible composite material and preparation method thereof ) 是由 郑磊 刘圣千 郭杰 陈思 石彦超 吴家红 武国军 康建钊 于 2021-09-06 设计创作，主要内容包括：本发明涉及复合材料领域,具体涉及一种近似各向同性柔性复合材料及制备方法。柔性复合材料由纤维承力单元和薄膜整体热压而成,所述复合材料的纤维承力单元由三组复合纤维长丝组成,纤维长丝接触位置通过热塑性包缠纱热熔固定。本专利采用一种由三组互成角度长丝呈三角形均匀分布的平面承力结构作柔性复合材料的承力层,因此柔性复合材料具有近似各向同性的特点。这种承力层沿着各方向承载能力较为均匀,无论受力方向是否与长丝方向一致,柔性复合材料不存在明显的抵御剪切破坏的薄弱方向。即便是由较稀薄的承力层制备的柔性复合材料也具有较好的结构稳定性。(The invention relates to the field of composite materials, in particular to an approximately isotropic flexible composite material and a preparation method thereof. The flexible composite material is formed by integrally hot-pressing a fiber bearing unit and a film, wherein the fiber bearing unit of the composite material is composed of three groups of composite fiber filaments, and the contact position of the fiber filaments is fixed by hot melting of thermoplastic wrapping yarns. The flexible composite material uses three groups of plane bearing structures which are mutually angled and uniformly distributed in a triangular shape as bearing layers of the flexible composite material, so that the flexible composite material has the characteristic of approximate isotropy. The bearing capacity of the bearing layer is uniform along all directions, and no matter whether the bearing direction is consistent with the filament direction or not, the flexible composite material does not have an obvious weak direction for resisting shearing damage. Even the flexible composite material prepared by thinner bearing layers has better structural stability.)

1. A near isotropic flexible composite characterized by: the film is formed by integrally hot-pressing a fiber bearing unit and a film, wherein the fiber bearing unit is composed of three groups of composite fiber filaments, and the contact position of the fiber filaments is fixed by thermoplastic wrapping yarns in a hot melting way.

2. The near-isotropic flexible composite material as claimed in claim 1, wherein: the three groups of composite fiber filaments are uniformly distributed in an equilateral triangle shape.

3. The near-isotropic flexible composite material as claimed in claim 1, wherein: the composite fiber filament is of a wrapping structure and is formed by wrapping core yarns with wrapping yarns.

4. The near-isotropic flexible composite material as claimed in claim 1, wherein: the film is a polyvinyl fluoride film, a polyvinylidene fluoride film, a nylon film, an ethylene/vinyl alcohol copolymer film or a nylon/ethylene/vinyl alcohol co-extrusion film.

5. A method for preparing an approximately isotropic flexible composite material is characterized by comprising the following steps:

s1: in the process of forming the force bearing structure unit of the flexible composite material, warp I is arranged in parallel at equal intervals, warp II is arranged above the warp I in parallel at equal intervals, the arrangement intervals of the warp I and the warp II are equal, and the warp I and the warp II form a gauze with an included angle of 60 degrees;

s2: the warp I and the warp II are arranged and positioned at equal intervals through a group of guide bars respectively;

s3: laying a weft yarn at the overlapping position of the warp yarn I and the warp yarn II, wherein the first weft yarn is laid above the overlapping position of the warp yarns, the second weft yarn is laid below the overlapping position of the warp yarns and is sequentially and repeatedly arranged, and the weft yarns are arranged and positioned at equal intervals through a group of guide bars;

s4: the gauze which is laid and positioned by a compression roller in a hot pressing way enables polyvinyl formal or polyurethane fiber wrapped on the outer surface of the filament at the overlapping position of warp and weft yarns to be subjected to hot melt adhesion, so that the forming of a bearing unit is realized, and then the bearing unit is cooled and shaped by the compression roller and is wound into a coil;

s5: and carrying out integral hot pressing on the bearing unit and the air bag material film, carrying out hot melting on the polyvinyl formal or polyurethane fiber wrapped on the outer surface of the filament again, and carrying out hot pressing and bonding with the film to form a whole, thereby completing the preparation and forming of the flexible composite material.

6. The method for preparing the approximately isotropic flexible composite material as claimed in claim 5, wherein the spacing between the warp yarn I and the warp yarn II of S1 is in the range of 0.5 cm-4.0 cm.

7. The method of preparing a near-isotropic flexible composite as claimed in claim 5, wherein: the hot pressing temperature of the S5 is 90-150 ℃.

8. The near-isotropic flexible composite material as claimed in claim 3, wherein: the core yarn is ultra-high molecular weight polyethylene fiber, aromatic polyamide fiber or wholly aromatic polyester filament fiber.

9. The near-isotropic flexible composite material as claimed in claim 3, wherein: the wrapping yarn is polyvinyl formal fiber or polyurethane fiber.

Technical Field

The invention relates to the field of composite materials, in particular to an approximately isotropic flexible composite material and a preparation method thereof.

Background

The flexible composite material for the airship generally uses a 0 DEG/90 DEG two-system mutually-perpendicular filament woven fabric as a bearing layer, the plane fabric with the orthogonal structure can effectively transfer load in the filament direction, but if the bearing direction is not consistent with the filament direction, the deformation and damage resistance of the flexible composite material is greatly reduced, particularly in the 45 DEG direction. In addition, when the flexible composite material is impacted by normal external force, stress concentration is easy to occur on the material at the stressed position. Therefore, the flexible composite material made of the 0 degree/90 degree woven fabric is easy to damage when the flexible composite material is subjected to oblique external force and normal external force.

Disclosure of Invention

Technical problem to be solved by the invention

The invention provides an approximately isotropic flexible composite material and a preparation method thereof, which aim to solve the problem of anisotropy of a flexible composite material using a planar bidirectional woven fabric as a bearing layer.

Technical scheme adopted by the invention for solving technical problem

The approximately isotropic flexible composite material is formed by integrally hot-pressing a fiber bearing unit and a film, wherein the fiber bearing unit of the composite material consists of three groups of composite fiber filaments, and the contact positions of the fiber filaments are fixed by thermoplastic wrapping yarns in a hot melting manner.

Furthermore, the three groups of composite fiber filaments are uniformly distributed in an equilateral triangle shape.

Furthermore, the composite fiber filament is of a wrapping structure and is formed by wrapping core yarns with wrapping yarns.

Further, the film is a polyvinyl fluoride film, a polyvinylidene fluoride film, a nylon film, an ethylene/vinyl alcohol copolymer film or a nylon/ethylene/vinyl alcohol co-extrusion film.

A method for preparing an approximately isotropic flexible composite material comprises the following steps:

s1: in the process of forming the bearing structure unit of the flexible composite material, warp yarns I are arranged in parallel at equal intervals; after the warp I is arranged, the warp II is arranged above the warp I in parallel at equal intervals, and the arrangement intervals of the warp I and the warp II are equal; the spacing range is 0.5 cm-4.0 cm, and the warp I and the warp II form a gauze with an included angle of 60 degrees;

s2: the warp I and the warp II are arranged and positioned at equal intervals through a group of guide bars respectively;

s3: laying a weft yarn at the overlapping position of the warp yarn I and the warp yarn II, wherein the first weft yarn is laid above the overlapping position of the warp yarns, and the second weft yarn is laid below the overlapping position of the warp yarns and is sequentially and repeatedly arranged; the weft yarns are arranged and positioned at equal intervals through a group of guide bars;

s4: the gauze which is laid and positioned by a compression roller in a hot pressing way enables polyvinyl formal or polyurethane fiber wrapped on the outer surface of the filament at the overlapping position of warp and weft yarns to be subjected to hot melt adhesion, so that the forming of a bearing unit is realized, and then the bearing unit is cooled and shaped by the compression roller and is wound into a coil;

s5: and carrying out integral hot pressing on the bearing unit and the flexible composite material film, carrying out hot melting on the polyvinyl formal or polyurethane fiber wrapped on the outer surface of the filament again, and carrying out hot pressing and bonding with the film to form a whole, thereby completing the preparation and forming of the flexible composite material.

Further, the hot pressing temperature of the S5 is 90-150 ℃.

Advantageous effects obtained by the present invention

The invention provides an approximately isotropic flexible composite material and a preparation method thereof, wherein a simpler method is adopted to realize that the mechanical property of the flexible material is approximately isotropic, compared with the existing 0 degree/90 degree two-system woven fabric flexible composite material, the flexible composite material has a weak direction without obvious shearing damage resistance, the flexible composite material is uniformly stressed and deformed in the circumferential direction, and the flexible composite material has better structural stability.

Drawings

FIG. 1: a schematic view of a near isotropic flexible composite;

FIG. 2: the structural schematic diagram of the force bearing unit of the approximately isotropic flexible composite material;

FIG. 3: wrapping the structured fiber filaments;

wherein: 1-film, 2-bearing unit, 3-warp I, 4-warp II, 5-weft, 6-core yarn and 7-wrapping yarn.

Detailed Description

The flexible composite material uses three groups of plane bearing structures which are mutually angled and uniformly distributed in a triangular shape as bearing layers of the flexible composite material, so that the flexible composite material has the characteristic of approximate isotropy. The bearing capacity of the bearing layer is uniform along all directions, and no matter whether the bearing direction is consistent with the filament direction or not, the flexible composite material does not have an obvious weak direction for resisting shearing damage. When the flexible composite material is impacted by normal external force, the stress deformation of the flexible composite material in the circumferential direction is uniform, and the local stress concentration of the planar bidirectional fabric is not easy to occur. Even the flexible composite material prepared by thinner bearing layers has better structural stability.

The invention adopts the force bearing units which are distributed with three groups of filaments uniformly in an equilateral triangle as the force bearing layer of the flexible composite material, thereby realizing the approximate isotropy of the tensile property of the flexible composite material; the flexible composite material is formed by integrally hot-pressing a fiber bearing unit and a film, wherein the fiber bearing unit of the flexible composite material consists of three groups of non-interwoven composite fiber filaments with thermoplastic functions, wherein the three groups of composite fiber filaments comprise two groups of warps and one group of wefts, the three groups of composite fiber filaments are uniformly distributed in an equilateral triangle, the contact positions of the fiber filaments are fixed by hot melting through thermoplastic wrapping yarns, the fiber filaments with the thermoplastic functions are of a wrapping structure, the core yarn is any one of ultra-high molecular weight polyethylene fibers, aromatic polyamide fibers and fully aromatic polyester filament fibers, and the wrapping fibers are any one of polyvinyl formal and polyurethane fibers; the film adopted by the flexible composite material comprises any one of a polyvinyl fluoride film, a polyvinylidene fluoride film, a nylon film and an ethylene/vinyl alcohol copolymer film; the air bag material adopts an integral hot pressing process, the flexible composite material has smooth and flat appearance, good integrity and approximately isotropic mechanical property. The forming process of the bearing structure unit of the flexible composite material comprises the following steps: the warp yarns I are arranged in parallel at equal intervals; after the warp I is arranged, the warp II is arranged above the warp I in parallel at equal intervals, and the warp I and the warp II are arranged at equal intervals; the spacing range is 0.5 cm-4.0 cm, and the warp I and the warp II form a gauze with an included angle of 60 degrees; the warp I and the warp II are arranged and positioned at equal intervals through a group of guide bars respectively; laying a weft yarn at the overlapping position of the warp yarn I and the warp yarn II, wherein the first weft yarn is laid above the overlapping position of the warp yarns, and the second weft yarn is laid below the overlapping position of the warp yarns and is sequentially and repeatedly arranged; the weft yarns are arranged and positioned at equal intervals through a group of guide bars; the gauze which is laid and positioned by a compression roller in a hot pressing way enables polyvinyl formal or polyurethane fiber which is wrapped on the outer surface of the filament at the overlapping position of warp and weft yarns to be subjected to hot melting adhesion, so that the forming of a bearing unit is realized, and then the bearing unit is cooled and shaped by the compression roller and is wound into a coil; carrying out integral hot pressing on the bearing unit and the flexible composite material film, wherein the hot pressing temperature is as follows: and (3) carrying out hot melt adhesion on the polyvinyl formal or polyurethane fibers wrapped on the outer surface of the filament at the temperature of between 90 and 150 ℃, and carrying out hot press adhesion on the polyvinyl formal or polyurethane fibers and the film to form a whole, thereby completing the preparation and forming of the flexible composite material.

In order to make the objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures 1-3 are described in detail. It is obvious that the described embodiments are only some, not all embodiments of the proposed solution. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention further explains the approximately isotropic flexible composite material and the preparation method by taking the airbag material as an example.

Example 1

The air bag material consists of a polyvinylidene fluoride film and a polyarylate fiber bearing unit wrapped by polyurethane fiber, wherein the polyvinylidene fluoride has the thickness of 50 mu m, the width of 1.2m and white color. A force bearing unit: the polyarylate fibers were 400 denier filaments and the wrapped yarn was 100 denier polyurethane fibers. The side length of the equilateral triangle of the bearing unit is 2.0 cm. The 0-degree tensile strength of the air bag material is 146N/cm, the 90-degree tensile strength of the air bag material is 152N/cm, and the 45-degree tensile strength of the air bag material is 172N/cm. The thickness of the air bag material is 0.1mm, the appearance is smooth, and the size stability is good.

Example 2

The air bag material consists of a nylon, ethylene and vinyl alcohol co-extruded film and an ultrahigh molecular weight polyethylene fiber bearing unit wrapped by polyethylene fibers, wherein the nylon, ethylene and vinyl alcohol co-extruded film has the thickness of 20 mu m and the width of 1.2m and is transparent. A force bearing unit: the ultra-high molecular weight polyethylene fiber is a 50-denier filament, and the wrapping yarn is a 50-denier polyvinyl formal fiber. The side length of the equilateral triangle of the bearing unit is 1.5 cm. The 0-degree tensile strength of the air bag material is 176N/cm, the 90-degree tensile strength of the air bag material is 182N/cm, and the 45-degree tensile strength of the air bag material is 203N/cm. The thickness of the air bag material is 0.05mm, and the integrity is good.