KR20110073841A - Composite of aramid and method for manufacturing the same - Google Patents

Abstract

PURPOSE: An aramid composite and a method for preparing the same are provided to improve workability and adhesion. CONSTITUTION: An aramid composite contains aramide fabric and resin layer. The resin layer is impregnated into the aramid fabric. The resin layer contains phenolic resin, polyvinyl butyral resin, and inorganic particle. The content of the resin layer is 10-20 weight%. The inorganic particle contains carbon nanotubes. The inorganic particle also contains nanoclay or zeolite.

Description

Aramid composite material and manufacturing method therefor {Composite of aramid and method for manufacturing the same}

TECHNICAL FIELD The present invention relates to an aramid composite material and a method for manufacturing the same, and more particularly, to an aramid composite material and a method for manufacturing the same that can be used for bulletproof or building and civil engineering materials.

Aramid fibers include para-aramid fibers having a structure in which benzene rings are linearly connected through an amide group and meta-aramid fibers having a bent structure. Among these, para-aramid fibers have high strength, high elasticity, and the like, and thus are used as sports articles, body armor, protective clothing, and composite materials.

Composites consist of reinforcements that serve to support external forces and matrix resins that protect these reinforcements and improve processability. In particular, composite materials including aramid reinforcing agents are being used in various fields such as aircraft, sports, and automobiles because of their excellent mechanical and thermal properties.

Composite materials containing such aramid fibers generally use a lot of phenolic resins for the matrix resin. However, phenolic resins are vulnerable to impact due to their hard properties and poor adhesion due to structural differences with aramid. When a composite material composed of such a phenol resin is used for a bulletproof helmet or the like, there is a problem that the bulletproof performance of the bulletproof helmet is inferior.

Aramid fibers, on the other hand, have a low elastic modulus and poor adhesion to general resins compared to carbon fibers. When using the composite material consisting of such aramid as a reinforcement for civil engineering or building repair and reinforcement materials, there is a problem that the durability of the building is low, such as low shear strength and bending strength of the repair and reinforcement materials.

Accordingly, the present invention relates to an aramid composite material and a method of manufacturing the same that can prevent the problems caused by the above limitations and disadvantages of the related art.

An advantage of the present invention is to provide an aramid composite material having excellent antiballistic performance by improving the adhesion between aramid and a resin and a method of manufacturing the same.

Another advantage of the present invention is to provide an aramid composite material and a manufacturing method thereof that can be used as a repair or reinforcement material for building or civil engineering with excellent durability by improving shear strength and bending strength.

In order to achieve the above advantages, and in accordance with the object of the present invention, aramid fabric; And a resin layer impregnated in the aramid fabric, wherein the resin layer is provided with a composite material containing phenol resin, polyvinyl butyral resin, and inorganic particles.

In another aspect of the invention, the step of preparing the aramid fabric; Preparing a composition comprising a phenol resin, a polyvinyl butyral resin, and inorganic particles; And impregnating the composition into the aramid fabric to produce a resin layer.

According to the present invention by the above configuration has the following effects.

First, the aramid composite material according to the present invention includes the phenol resin, polyvinyl butyral resin and inorganic particles to improve the workability and adhesive force has an effect of greatly improving the bulletproof performance of bulletproof products.

Second, since the aramid composite material according to the present invention is manufactured through a laminating process, the resin content can be greatly reduced, thereby reducing material costs and improving weight.

Third, since the aramid composite material according to the present invention contains inorganic particles such as nano-sized carbon nanotubes, the shear strength and bending strength are excellent, so that the durability of the building is greatly increased when used as a repair or reinforcement material for construction or civil engineering. There is an effect to be improved.

Hereinafter, the present invention will be described in detail.

The aramid composite material according to the present invention includes an aramid fabric and a resin layer impregnated in the aramid fabric, the resin layer comprises a phenol resin, polyvinyl butyral resin (polyvinylbutyral), and inorganic particles.

The aramid fabric serves to enhance the mechanical properties and form stability of the composite material, such aramid has good heat resistance and high tensile strength and elastic modulus, so that the high durability is required in the fields of aircraft, automobiles, construction, etc. Can be.

The aramid fabric may be made in various forms depending on the field of use. That is, the aramid fabric may be formed in the form of unidirectional fibers, woven fabrics, knitted fabrics, braids, and the like.

Aramid fabric is made of a cross between the warp and the weft, and can easily control the density and the like and is suitable for mass production. However, since the slope and the weft interweave with each other, as the stress is concentrated at the intersection point, the ballistic resistance may be somewhat reduced.

One-way aramid fabric means an aggregate consisting of all the aramid filaments are arranged in the same direction, there is no intersection point can prevent the concentration of stress and thus can express more excellent ballistic performance. However, the one-way aramid fabric is excellent in physical properties in the vertical direction, but the physical properties in the left and right direction is weak.

Braid aramid fabric can be useful for making composites of the same type as rods. In particular, rod-shaped composite material may be usefully used as a repair or reinforcement material for construction or civil engineering.

The composite material is usually composed of a reinforcing agent such as aramid fabric and a matrix resin layer surrounding the reinforcing agent. This resin layer serves to protect the reinforcing agent from the outside and improve moldability. The resin layer of the present invention comprises a phenol resin, a polyvinyl butyral resin, and inorganic particles.

Since the phenolic resin has a good heat resistance, excellent electrical insulation, and a rigid three-dimensional structure, the phenolic resin has excellent chemical resistance and good affinity with various other materials, so that it can be applied to various fields.

However, phenolic resins are easily brittle, so formability is poor, impact strength is low, and affinity is low due to structural differences with aramid fibers.

Since the polyvinyl butyral resin is excellent in flexibility (flexibility), when used in combination with a brittle phenolic resin, it can easily be broken properties.

However, the composite material prepared from the resin composition mixed with phenol resin and polyvinyl butyral resin does not significantly improve the affinity between aramid and resins, so that the bulletproof performance is not greatly improved when used in bulletproof helmets and the like, and the shear strength (shear strength) and flexural strength (falling strength) is falling, when used as a repair or reinforcement material for construction or civil engineering did not meet the level of durability required by the industry.

Accordingly, the present invention improves the affinity, shear strength and bending strength of the composite material by adding inorganic particles to the phenol resin and polyvinyl butyral resin.

The inorganic particles may serve as additives to improve the interaction between the matrix, which is the resin layer, and the aramid, which is the reinforcing agent. Therefore, the composite material prepared therefrom has improved adhesion and toughness between the resin layer and the aramid, and thus the antiballistic performance, the shear strength and the bending strength are increased. In addition, as inorganic particles act as toughening agents, the ballistic resistance and shear strength of composite materials are improved by improving brittle properties, decreasing elastic modulus, increasing molecular chain fluidity, and increasing elongation. And bending strength is improved.

In addition, the inorganic particles have a bridge mechanism between the aramid fibers to improve the interlayer adhesion of the composite material and to prevent cracks from spreading, thereby improving the toughness of the composite material.

In addition, the inorganic particles are small in size and are distributed among the aramid fibers to act as an additional filler, thereby preventing the concentration of stress, thereby improving the adhesion, shear strength, toughness of the composite material And shape stability is improved.

The inorganic particles of the present invention may include carbon nanotubes. The carbon nanotubes are not particularly limited in shape and size, but may preferably be single-walled carbon nanotubes or multi-walled carbon nanotubes having an average diameter of 1 to 100 nm. When the average diameter of the carbon nanotubes is less than 1 nm, since the carbon nanotubes are not dispersed and agglomerated smoothly, improvement of adhesiveness and shear strength of the composite material cannot be expected, and the average diameter of the carbon nanotubes is 100 nm. When it exceeds, the flexibility of the resin layer may be lowered and the moldability may be deteriorated.

The carbon nanotubes may be formed in an amount of 0.01 to 5 wt% based on the weight of the entire composite material. If the content of the carbon nanotubes is less than 0.01% by weight can not play a role of sufficient toughness agent, the performance of the composite material is not significantly improved, if the content of the carbon nanotubes exceeds 5% by weight, the composite material While its performance does not improve significantly, economics can only be reduced by increasing production costs.

The inorganic particles may include nanoclays. The nanoclay is not limited in type, shape and size, but may be natural or synthetic layered clay consisting of plate-like layers having a thickness of 7 to 12 mm 3 and an aspect ratio of 10 to 5000. Representative examples of the layered clay are montmorillonite, bentonite, hectorite, hectorite, fluorohectorite, saponite, beidelite, nontronite ( nontronite, stevensite, vermiculite, volkonskoite, magadite, kenyalite, or derivatives thereof.

The inorganic particles may include zeolite. The zeolite is not limited in kind, shape and size, but may be natural or synthetic zeolite.

The content of the resin layer may be 10 to 20% by weight relative to the total composite material. If the content of the resin layer is less than 10% by weight, since the resin is not sufficiently impregnated in the aramid fabric may be inferior in adhesion between the aramid and the resin layer, if the content of the resin layer exceeds 20% by weight, As the resin content increases, the performance of the composite material decreases.

In the embodiments described below, detailed description of the same parts as the manufacturing process of the composite material of the above-described configuration of the composite material will be omitted.

Method for producing a composite material of the present invention, the step of preparing an aramid fabric, a step of preparing a composition comprising a phenolic resin, polyvinylbutyral and inorganic particles, and impregnating the composition into the aramid fabric It comprises the step of preparing a resin layer.

The step of preparing the aramid fabric and the step of preparing the composition does not have a particular process sequence.

First, the step of preparing the aramid fabric will be described. Aramid fabric may be in the form of woven, unidirectional, braid, etc., they can be produced by conventional methods. For example, the aramid fabric can be completed by using aramid filaments having a tensile strength of 20 g / d or more for warp and weft yarn by adjusting the density according to the application. In addition, the one-way aramid fabric can be completed by releasing the aramid filaments in a plurality of bobbin wound around the aramid filament and arranging the aramid filaments side by side while maintaining a uniform tension. In addition, the aramid braid can be completed by feeding the aramid filaments to the brazing device to knit into a tube shape.

Next, the steps for preparing the composition will be described. The composition includes a phenol resin, a polybutylral resin and inorganic particles, and may be in the form of a solution or a film.

Such a composition solution may consist of a resin, inorganic particles, and a solvent. The solvent may be used a variety of solvents such as dimethylformamide, dimethylacetamide, methanol, etc., it is preferable to select appropriately according to the inorganic particles to be added.

Inorganic particles may be added to the resin solution in which the resin is dissolved in a solvent to uniformly disperse the composition solution. The inorganic particles may be pretreated to improve the dispersibility between the inorganic particles before adding to the resin solution. The composition solution thus prepared may be directly applied to the aramid fabric prepared as described above through a dipping method. Alternatively, the composition solution may be prepared by using an appropriate method, and then the films may be laminated on an aramid fabric.

Next, the steps for producing the resin layer will be described. The manufacturing process may vary slightly depending on the type of composition used. That is, in the case of using the composition solution in the solution state, the resin layer may be prepared by applying the composition solution to the aramid fabric in an appropriate content using an immersion process, etc., and then performing a drying process to remove the solvent. On the other hand, when using a film-like composition, it is possible to manufacture a resin layer through a laminating process, that is, a step of fusion bonding the film under high temperature and high pressure after attaching the film to the aramid fabric.

When the resin layer is manufactured through the laminating process, the resin may be uniformly impregnated in the entire aramid fabric, and there is an advantage in that the content of the components of the resin can be precisely controlled. Therefore, when the composite material prepared through the laminating process is used for a bulletproof helmet, a bulletproof helmet having excellent weight reduction and bulletproof performance can be manufactured, and when used in a building reinforcing material, a reinforcing material having excellent shear strength and bending strength is used. It can manufacture.

The content of polyvinyl butyral in the resin layer may be 30 to 70% by weight. If the content of the polyvinyl butyral is less than 30% by weight, the flexibility is poor and poor workability, while if the content of the polyvinyl butyral exceeds 70% by weight, the flexibility is good but the heat resistance is poor do.

Hereinafter, the present invention will be described in detail through Examples and Comparative Examples. However, the following examples are only intended to help the understanding of the present invention, and the scope of the present invention should not be limited.

Example  One

Para-phenylenediamine and terephthaloyl dichloride were polymerized in an N-methyl-2-pyrrolidone polymerization solvent to prepare a poly paraphenylene terephthalamide polymer, which was then dissolved in concentrated sulfuric acid solvent to spin dope. Was prepared, and the spinning dope was spun through a spinneret and then solidified to prepare 1,000 denier aramid fibers.

The aramid fibers were then applied to warp and weft yarns and woven into plain weave to produce aramid fabrics having a density of 350 g / m 2.

After dissolving 70 g of phenol resin and 25 g of polyvinyl butyral resin in a methanol solvent, 2.5 g of carbon nanotubes (single wall, Carbon Nanotechnologies Inc.) were added as inorganic particles to disperse evenly to form a composition solution, and then the methanol was removed. A film composition was prepared.

Subsequently, the film composition was attached onto the aramid fabric and pressure was applied in a chamber maintaining a temperature of 40 ° C. to obtain a composite material having a resin layer of 15% by weight relative to the aramid fabric.

Example  2

In Example 1 described above, the composite was prepared in the same manner as in Example 1 except for using montmolylonite (Garamite-1958, Southern Clay Product, USA) modified with alkyl ammonium as nanoclay instead of carbon nanotubes. Obtained the material.

Example  3

In Example 1 described above, a composite material was obtained by the same method as Example 1 except for using zeolite (TS-1 zeolite, xTiO ₂ (1-x) SiO ₂ , KICET) instead of carbon nanotubes.

Comparative example

In Example 1 described above, a composite material was obtained by the same method as Example 1 except for using the composition solution to which the inorganic particles were not added.

The physical properties of the composite material prepared according to Examples and Comparative Examples were measured by the following method and are shown in Table 1 below.

Adhesion

After laminating two composite materials prepared in Examples and Comparative Examples, a sample was prepared by molding in a mold maintained at a pressure of 160 bar and a temperature of 150 ° C. for 20 minutes.

The adhesive strength (kgf) of each of the samples was measured by a peel test according to ASTM D903. On the other hand, the test was carried out at a load cell of 1kgf and a speed of 100mm / min.

Shear strength

The shear strength of each sample was measured by ASTM D2344-84 (Standard test method for apparent interlaminar shear strength of parallel fiber composite by short-beam method), and was calculated by the following equation.

Shear strength = 0.75P / bh

Where P is a fail load and b and h are the width and thickness of the specimen, respectively.

Bending strength

Flexural strength of each of the samples was measured by ASTMD790.

Bulletproof performance

Samples were prepared by laminating 15 composite materials prepared according to Examples and Comparative Examples, and molding them in a mold maintained at a pressure of 160 bar and a temperature of 150 ° C. for 30 minutes.

Each sample was measured for ballistic performance at V50, the average speed between full penetration and partial penetration with Cal.22 diameter fragment debris (FSP) according to MIL-STD-662F.

division Adhesive force (㎏f) Shear strength (MPa) Bending strength (GPa) Bulletproof performance (V50 = m / s) Example 1 4.4 42 7.9 690 Example 2 4.1 40 7.4 660 Example 3 3.9 38 7.2 650 Comparative example 2.1 25 6.6 600

Claims (10)

Aramid fabric; And Including the resin layer impregnated in the aramid fabric, The resin layer is a composite material containing a phenol resin, polyvinyl butyral resin, and inorganic particles. The method of claim 1, The inorganic particles are composite materials comprising carbon nanotubes. The method of claim 2, Composite material, characterized in that the average diameter of the carbon nanotubes 1 ~ 100nm. The method of claim 2, Composite material, characterized in that the content of the carbon nanotubes of 0.01 to 5% by weight. The method of claim 1, The inorganic particles are composite material characterized in that it comprises nanoclay or zeolite. The method of claim 1, Composite material, characterized in that the content of the resin layer is 10 to 20% by weight. Preparing an aramid fabric; Preparing a composition comprising a phenol resin, a polyvinylbutyral resin, and inorganic particles; And Method for producing a composite material comprising the step of impregnating the composition to the aramid fabric to produce a resin layer. The method of claim 7, wherein The step of preparing the resin layer is a method for producing a composite material, characterized in that it comprises a laminating process. The method of claim 8, The laminating process is a method for producing a composite material, characterized in that using the film containing the composition. The method of claim 7, wherein The inorganic particle manufacturing method of a composite material comprising at least one of carbon nanotubes, nanoclays and zeolites.