KR20140023757A - Laminate including thermoplastic resin impregnated continuous carbon fiber and method of preparing the same - Google Patents

Abstract

Provided is a laminate sequentially including a thermoplastic resin impregnated continuous fiber surface layer, a thermoplastic resin layer, and a thermoplastic resin impregnated continuous carbon fiber middle layer. The continuous fiber is selected from a group consisting of carbon fibers, glass fibers, aramid fibers, and a combination thereof.

Description

TECHNICAL FIELD [0001] The present invention relates to a laminated body including thermoplastic resin-impregnated continuous fibers,

To a laminate including a thermoplastic resin-impregnated continuous fiber and a method of producing the laminate.

Among the industrial fibers, carbon fiber has been used in a wide range of fields, and the demand is increasing every year. As a method for obtaining a molding substrate using such a carbon fiber-reinforced composite material, there is a method of impregnating a carbon fiber into a bath containing a matrix resin or the like.

As a method of obtaining a molding substrate using the carbon fiber-reinforced composite material, there is a compression molding method through film stacking. However, there is a problem that it is difficult to produce a molded product using a carbon fiber-reinforced composite material so as to have a smooth surface quality by compression molding. The surface of the formed product may not be smooth due to the unevenness of the fiber due to the bending of the fiber, and the shape of the fabric may be exposed on the surface.

High surface quality is required for use in the appearance of household appliances, automobiles, and the like. Particularly, there is a demand for a shape having a smooth surface while revealing a twill pattern using 3k roving of carbon fiber. In order to satisfy this requirement, it is necessary to produce a product having a 3k carbon fiber twill pattern on the outer surface and showing the mirror quality.

However, since the high price of the twill fabrics of 3k carbon fiber and impregnability are difficult, it is difficult to meet the above demand.

An embodiment of the present invention provides a thermoplastic resin-impregnated continuous fiber-containing laminate excellent in mechanical properties such as flexural strength and flexural rigidity while realizing a smooth mirror-finished surface.

Another embodiment of the present invention provides a method of making the laminate.

In one embodiment of the present invention, there is provided a laminate comprising a surface layer of continuous fibers impregnated in a thermoplastic resin, a thermoplastic resin layer, and an intermediate layer of continuous fibers impregnated in the thermoplastic resin. Wherein the surface layer is a sheet comprising a fabric in which continuous fibers of about 1000 to about 5000 fibers are woven, the intermediate layer being a sheet comprising a continuous fiber woven fabric comprising about 10,000 to about 40,000 fiber bundles.

The thickness of the thermoplastic resin layer may be about 100 탆 to about 200 탆.

The laminate may contain 20 to 60 wt% of continuous fibers.

The diameter of the fiber bundles of continuous fibers included in the surface layer may be about 3 mm to about 7 mm.

The diameter of the fiber bundles of continuous fibers included in the intermediate layer may be about 10 mm to about 40 mm.

The continuous fibers may be selected from the group consisting of carbon fibers, glass fibers, aramid fibers, and combinations thereof.

The intermediate layer may have a flexural strength of about 400 MPa to about 750 MPa and a flexural stiffness of about 35 GPa to about 46 GPa.

The surface layer and the intermediate layer may be formed by compression-molding after stacking sheets of at least one prepreg shape.

The laminate may be formed such that both surfaces of the thermoplastic resin layer are respectively in contact with the surface layer and the intermediate layer.

The laminate may be a laminate in which a first surface layer, a first thermoplastic resin layer, an intermediate layer, a second thermoplastic resin layer, and a second surface layer are sequentially laminated.

The thermoplastic resin impregnated with the continuous fiber to form the surface layer, the thermoplastic resin impregnated with the continuous fiber to form the intermediate layer, and the thermoplastic resin included in the thermoplastic resin layer are each independently polytetrafluoroethylene. PTFE, polyethylene, polypropylene, polystyrene, polyphenylene oxide (PPO), polyvinyl chloride (PVC), polyethylene terephthalate (PET) , Nylon 6.6, polymethyl methacrylate (PMMA), and combinations thereof.

The laminate may have a flexural strength of about 500 MPa to about 700 MPa.

In another embodiment of the present invention, there is provided a method of making a continuous fiber web comprising impregnating a thermoplastic resin with a continuous fiber woven fabric comprising about 1000 to about 5000 fiber bundles to produce an intermediate layer; Laminating a thermoplastic resin layer on at least one side of the intermediate layer; Impregnating a thermoplastic resin woven fabric consisting of about 10000 to about 40000 fiber bundles into a thermoplastic resin to produce at least one surface layer; Laminating the surface layer on top of the at least one thermoplastic resin layer; And compressing the intermediate layer, the at least one thermoplastic resin layer, and the at least one surface layer to produce a laminate.

The compression molding may be performed after raising the temperature of the laminate from about 250 ° C to about 300 ° C.

The compression molding may be performed by raising the temperature of the compression molding mold to about 90 캜 to about 150 캜.

The compression molding may be performed at a pressure of from about 1 MPa to about 10 MPa.

The surface layer and the intermediate layer may be prepared by laminating sheets of at least one prepreg shape.

The laminate has excellent mechanical properties such as flexural strength and flexural rigidity while realizing a smooth mirror-finished surface, and can use general-purpose continuous fibers to improve productivity while lowering manufacturing cost.

1 is a schematic cross-sectional view of a laminate according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

In the drawings, the thickness is enlarged to clearly represent the layers and regions. In the drawings, for the convenience of explanation, the thicknesses of some layers and regions are exaggerated.

Hereinafter, the formation of any structure in the "upper (or lower)" or the "upper (or lower)" of the substrate means that any structure is formed in contact with the upper surface (or lower surface) of the substrate However, the present invention is not limited to not including other configurations between the substrate and any structure formed on (or under) the substrate.

1 is a cross-sectional view of a laminated body 100 according to an embodiment of the present invention. The laminated body includes surface layers 11a and 11b of thermoplastic resin-impregnated continuous fibers, thermoplastic resin layers 12a and 12b and thermoplastic resin- And an intermediate layer 13 of fibers sequentially.

The surface layers 11a and 11b and the intermediate layer 13 may be formed of a sheet made by impregnating a fabric in which a continuous fiber is woven with a thermoplastic resin and the surface layers 11a and 11b may be formed of about 1000 to about 5000 fibers The continuous layer of continuous fibers is a sheet comprising a woven fabric, wherein the intermediate layer 13 can be formed from a sheet comprising a fabric in which continuous fibers of about 10,000 to about 40,000 fiber bundles are woven.

The laminate (100) has a surface pattern of such fibers by exposing a fabric woven with continuous fibers having a fiber bundle of the above-mentioned range on the surface.

The continuous fibers mean fibers that are structurally connected together like a fabric, and the unbroken fibers can be subjected to a load applied evenly over the entire fiber when a load is applied.

The continuous fiber may be any known fiber used for industrial purposes without limitation. For example, carbon fiber, glass fiber, aramid fiber and the like may be used.

Continuous fibers composed of about 1000 to about 5000 fiber bundles forming the surface layers 11a and 11b have a small fiber diameter, thereby enabling the realization of smooth surface properties. However, since such thin continuous fibers are high in price, use of a large amount thereof increases the unit price. Therefore, the laminate uses only such continuous fibers as the surface layer, and the intermediate layer 13 includes a fabric in which continuous fibers composed of about 10,000 to about 40,000 fiber bundles are woven to lower the manufacturing cost.

The diameter of the fiber bundles of the continuous fibers forming the surface layers 11a and 11b may be about 3 mm to about 7 mm. A fabric woven with continuous fibers having a diameter in the above range can impart mirror-surface quality to the surface layers 11a and 11b.

The continuous fibers of about 10,000 to about 40,000 fiber bundles used for producing the intermediate layer 13 can be easily obtained at a low price because the fibers are thicker than the continuous fibers for forming the surface layers 11a and 11b, It is possible to further improve the mechanical properties such as flexural strength and bending rigidity of the laminate at the same time under the same impregnation conditions because the impregnation with resin is excellent.

For example, a sheet prepared by impregnating a fabric woven with the continuous fibers contained in the intermediate layer 13 into a thermoplastic resin may have a flexural strength of about 400 MPa to about 750 MPa, specifically about 450 MPa to about 680 MPa Lt; / RTI > In addition, the sheet prepared by impregnating the fabric woven with the continuous fibers contained in the intermediate layer 13 into a thermoplastic resin has a flexural rigidity of about 35 GPa to about 46 GPa, specifically about 37 GPa to about 44 GPa due to high impregnability .

The diameter of the fiber bundles of the continuous fibers forming the intermediate layer 13 may be about 10 mm to about 40 mm. The continuous fibers forming the intermediate layer 13 may be wider fibers. A fabric woven with continuous fibers having a diameter in the above range is excellent in impregnation with a thermoplastic resin, so that the mechanical properties such as bending strength and bending rigidity of the laminate can be improved.

The laminate 100 simultaneously contains the thermoplastic resin layers 12a and 12b together with the intermediate layer 13 including a fabric in which a continuous fiber composed of about 10,000 to about 40,000 fiber bundles is woven, It is possible to smoothly form the surface without deteriorating the physical properties of the surface.

Since the fabric used for the intermediate layer 13 uses a relatively thick continuous fiber, irregularities due to fiber bending are transferred to the surface, so that the surface of the molded product is not smooth and the shape of the fabric may be exposed on the surface. The laminate 100 can solve this problem by interposing the thermoplastic resin layers 12a and 12b between the surface layers 11a and 11b and the intermediate layer 13. [

The thermoplastic resin layers 12a and 12b are formed so that both surfaces of the thermoplastic resin layers 12a and 12b are in contact with the surface layers 11a and 11b and the intermediate layer 13, respectively, in order to realize a smooth mirror- Lt; / RTI >

The thickness of the thermoplastic resin layers 12a and 12b may be about 100 탆 to about 200 탆, specifically about 100 탆 to about 150 탆. The thermoplastic resin layers 12a and 12b having the above thickness can be mirror-finished on the surface of the laminate 100 so as to be suitable for use in the appearance of household appliances and automobiles.

The thermoplastic resin forming the thermoplastic resin layers 12a and 12b is not particularly limited and a thermoplastic resin composition which can be molded into a known film or sheet can be used without limitation. For example, it is possible to use polytetrafluoroethylene (PTFE), polyethylene, polypropylene, polystyrene, polyphenylene oxide (PPO), polyvinyl chloride (PVC) ), Polyethylene terephthalate (PET), nylon 6.6, polymethyl methacrylate (PMMA), or a mixture thereof.

Hereinafter, the surface layers 11a and 11b and the intermediate layer 13 will be described in detail with respect to a sheet produced by impregnating a thermoplastic resin with a woven fabric in which continuous fibers are woven.

The fabric to which the continuous fibers are woven can be, for example, a twill or a plain fabric using roving of carbon fiber, glass fiber or aramid fiber. In one embodiment, the laminate 100 includes a continuous carbon fiber fabric in a twill pattern so that the twill pattern is exposed, but the surface may be smoothly mirror-finished.

The impregnating thermoplastic resin composition impregnated with the continuous fiber-woven fabric may include, without limitation, a polymer material having a property of being softened at a high temperature and hardening upon cooling, that is, a thermoplastic resin, and may include, for example, polytetrafluoro (PTFE), polyethylene, polypropylene, polystyrene, polyphenylene oxide (PPO), polyvinyl chloride (PVC), polyethylene terephthalate (PET), nylon 6.6, polymethyl methacrylate (PMMA), or a mixture thereof. The above-mentioned thermoplastic resin composition for impregnation may further contain various additives such as a reaction initiator if necessary.

The laminate 100 may comprise from about 20 to about 60 weight percent of continuous fibers, and specifically from about 20 to about 40 weight percent of continuous fibers. The surface layer 11a or 11b impregnated with the continuous fibers at the content ratio within the above range and the laminate 100 including the intermediate layer 13 have a relatively low fiber fraction and are impregnated with a thermoplastic resin The surface can be covered smoothly.

The surface layers 11a and 11b and the intermediate layer 13 may be formed by stacking a plurality of sheets of thermoplastic resin-impregnated continuous fibers. For example, a plurality of prepregs may be laminated on the surface layers 11a and 11b and the intermediate layer 13, respectively. According to the manufacturing method of the laminated body 100 described later, the respective layers are laminated and then subjected to a compression molding process. The surface layers 11a and 11b formed by stacking a plurality of prepregs and the intermediate layer 13 And is formed into a single composite material by a thermoplastic resin impregnated and impregnated under such high-temperature compression molding.

In one embodiment, the laminate 100 is a laminate having a first surface layer 11a, a first thermoplastic resin layer 12a, an intermediate layer 13, a second thermoplastic resin layer 12b, a second surface layer 11b may be sequentially stacked.

In other embodiments, the laminate may have a flexural strength of from about 500 MPa to about 700 MPa.

The laminate 100 can be used as various exterior materials or interior materials and can be applied to automobiles, airplanes, electric / electronic devices, optical instruments, precision instruments, and the like, to which lightweight, mechanical characteristics, dimensional stability, Equipment, entertainment / toys, home / office products, home appliances, building materials, and the like.

In another embodiment of the present invention, there is provided a method of making a continuous fiber web comprising impregnating a thermoplastic resin with a continuous fiber woven fabric comprising about 1000 to about 5000 fiber bundles to produce an intermediate layer; Laminating a thermoplastic resin layer on at least one side of the intermediate layer; Impregnating a thermoplastic resin with a continuous fiber woven fabric comprising about 10000 to about 40,000 fiber bundles to produce a surface layer; Laminating the surface layer on top of the at least one thermoplastic resin layer; And compressing the intermediate layer, the at least one thermoplastic resin layer, and the at least one surface layer to produce a laminate.

The surface layer and the intermediate layer may be formed by using a sheet in the form of a prepreg, or by laminating a plurality of sheets in the form of a prepreg. Each of the layers is laminated and then formed into a single composite material by the thermoplastic resin impregnated with the respective surface layers formed by laminating the plurality of prepregs in the compression molding process.

The higher the temperature of the compression-molding mold used in the compression molding, the better the mirror-surface quality of the surface of the molded body to be produced. For example, compression molding can be performed using a compression molding mold heated to about 90 캜 to about 150 캜. In one embodiment, a nickel chrome plated compression mold that is superior in terms of mirror-surface cleanliness, scratch resistance, etc. can be used.

For example, the laminate is heated to about 250 ° C. to about 300 ° C. using a convection oven for compression molding, and the surface of the mold is heated to about 90 ° C. to about 150 ° C. using a humidifier Molded into chrome-plated compression-molded moles, and compression-molded at a pressure of about 1 MPa to about 10 MPa for about 1 minute to about 5 minutes to produce the laminate.

Hereinafter, examples and comparative examples of the present invention will be described. The following embodiments are only examples of the present invention, and the present invention is not limited to the following embodiments.

( Example )

Manufacturing example  One

One piece of 3k woven carbon fiber was impregnated in a polyamide resin (PA6) at 270 캜 under 4 MPa for 10 minutes to prepare a prepreg for surface layer formation.

Production Example 2

One piece of 3 kg of woven carbon fiber was impregnated in a polyamide resin (PA6) at 270 캜 under 4 MPa for 5 minutes to prepare a prepreg for surface layer formation.

Manufacturing example  3

A 12-carat twill carbon fiber was impregnated in a polyamide resin (PA6) at 270 DEG C under 4 MPa for 10 minutes to prepare a prepreg for surface layer formation.

Manufacturing example  4

A 12-carat twill carbon fiber was impregnated with a polyamide resin (PA6) at 270 DEG C under 4 MPa for 5 minutes to prepare a prepreg for surface layer formation.

Example  One

A total of four surface layer prepregs prepared in Production Example 1 were prepared. On the other hand, a total of eight intermediate layer prepregs prepared in Production Example 3 were prepared.

On the other hand, two PA6 resin sheets having a thickness of 150 mu m were prepared.

Two sheets of the prepared prepreg for surface layer formation, the PA6 resin sheet, the eight prepregs for forming the intermediate layer, the PA6 resin sheet, and the two prepregs for surface layer formation were laminated in order, placed in a convection oven, As soon as it was taken out of the oven, it was placed in a nickel chromium-plated compression molding mold heated to 120 ° C and compression molded at a pressure of 4 MPa for 2 minutes to produce a laminate.

It was 60% by weight when the content of the carbon fiber was measured by an ash test on the prepared laminate.

Example  2

A prepreg for forming a surface layer, a PA6 resin sheet, and a prepreg for forming an intermediate layer prepared in Production Example 3 were prepared in the same manner as in Example 1.

Two sheets of the prepreg for surface layer formation, the PA6 resin sheet, the four prepregs for forming the intermediate layer, the PA6 resin sheet, and two prepregs for forming the surface layer were stacked in order, placed in a convection oven, heated to 270 DEG C, Was put into a nickel chromium-plated compression-molded mold heated to 120 ° C and compression-molded at a pressure of 4 MPa for 2 minutes to prepare a laminate.

Example  3

A prepreg for forming a surface layer, a PA6 resin sheet, and a prepreg for forming an intermediate layer prepared in Production Example 3 were prepared in the same manner as in Example 1.

Two sheets of prepreg for surface layer formation, PA6 resin sheet, 16 sheets of prepreg for forming an intermediate layer, 2 sheets of PA6 resin sheet and two sheets of prepreg for surface layer formation were laminated in order, and then placed in a convection oven. Was put into a nickel chromium-plated compression-molded mold heated to 120 ° C and compression-molded at a pressure of 4 MPa for 2 minutes to prepare a laminate.

Comparative Example  One

A prepreg for surface layer formation prepared in Preparation Example 1 and a prepreg for formation of an intermediate layer prepared in Production Example 3 were prepared in the same manner as in Example 1.

Two prepregs for forming a surface layer, eight prepregs for forming an intermediate layer, and two prepregs for forming a surface layer were stacked in order, and then placed in a convection oven and heated to 270 DEG C. Then, immediately after taking out of the oven, Molded into a plated compression molding mold, and compression molded at a pressure of 4 MPa for 2 minutes to produce a laminate.

Comparative Example  2

20 sheets of surface layer forming prepregs prepared in Production Example 1 were prepared in the same manner as in Example 1, and then 20 sheets of surface layer forming prepregs were laminated. Then, the prepregs were placed in a convection oven and heated to 270 DEG C, The resultant mixture was placed in a nickel-chrome-plated compression-molded mold having a raised temperature and compression-molded at a pressure of 4 MPa for 2 minutes to produce a laminate.

evaluation

[Impregnation Characteristic Evaluation]

Flexural strength and flexural rigidity were measured for Production Examples 1 to 4 (Instron universal testing machine, ASTM D-790 2 mm / min, 16: 1 span length ratio)

division Production Example 1 Production Example 2 Production Example 3 Production Example 4 Flexural Strength (MPa) 500 450 680 550 Flexural Stiffness (GPa) 37 35 44 38

As can be seen from the above results, in the case of 12k fibers, Examples 3 and 4 showed better impregnation than those of Preparation Examples 1 and 2 in the case of 3k fibers at the same time, The flexural rigidity is increased.

[Evaluation of physical properties of laminate]

The average values (Ra and Rz) of the surface irregularities of the laminate produced in Example 1-3 and Comparative Example 1-3 were measured using a surface roughness meter (illuminance meter SJ-301, Mitutoyo) Respectively. The smaller the average value of the irregularities, the more uniform the surface.

 The flexural strength and flexural rigidity of the laminate produced in Examples 1-3 and 1-3 were measured using an Instron universal testing machine (ASTM D-790 2 mm / min, ratio of 16: 1 span length) Are shown in Table 2 below.

division Ra (μm) Rz (μm) Flexural strength
(MPa) Example 1 0.23 1.07 600 Example 2 0.24 1.1 580 Example 3 0.26 1.09 650 Comparative Example 1 0.35 1.85 600 Comparative Example 2 0.47 3.12 500

From the above results, it was confirmed that all of the surface characteristics of Example 1-3 were superior to those of Comparative Example 1-2.

Further, in Examples 1-3, a prepreg of 3k-twilled carbon fibers and a prepreg of 12k-twilled carbon fibers, which were prepared by impregnating the same time-periodical resin, and prepregs of 12k- It can be confirmed that the flexural strength of the third embodiment is the highest, and that the flexural strength of the first embodiment is relatively high in the first embodiment. On the other hand, in Comparative Example 2, only prepregs of 3k twill carbon fibers in the prepregs of 3k twill carbon fibers and 12k twill carbon fibers prepared by impregnating the same time resin were used, .

100: laminate
11a, 11b: surface layer
12a, 12b: a thermoplastic resin layer
13: middle layer

Claims (17)

A surface layer of continuous fibers impregnated in the thermoplastic resin, a thermoplastic resin layer, and an intermediate layer of continuous fibers impregnated in the thermoplastic resin,
The surface layer is a sheet comprising a woven fabric of continuous fibers consisting of 1000 to 5000 fiber bundles, the intermediate layer is a sheet comprising a woven fabric of continuous fibers consisting of 10000 to 40000 fiber bundles
Laminates. The method of claim 1,
Wherein the thermoplastic resin layer has a thickness of 100 mu m to 200 mu m
Laminates. The method of claim 1,
Wherein said laminate comprises continuous fibers in an amount of 20 to 60 wt%
Laminates. The method of claim 1,
Wherein a fiber bundle of continuous fibers contained in the surface layer has a diameter of 3 mm to 7 mm
Laminates. The method of claim 1,
Wherein the fiber bundle of continuous fibers contained in the intermediate layer has a diameter of 10 mm to 40 mm
Laminates. The method of claim 1,
Wherein the continuous fibers are selected from the group consisting of carbon fibers, glass fibers, aramid fibers, and combinations thereof
Laminates. The method of claim 1,
Wherein the intermediate layer has a flexural strength of 400 MPa to 750 MPa and a flexural rigidity of 35 GPa to 46 GPa
Laminates. The method of claim 1,
Wherein the surface layer and the intermediate layer are formed by compression-molding after at least one prepreg-type sheet is laminated,
Laminates. The method of claim 1,
Wherein both surfaces of the thermoplastic resin layer are laminated so as to be in contact with the surface layer and the intermediate layer, respectively
Laminates. The method of claim 1,
The laminate is formed by sequentially stacking a first surface layer, a first thermoplastic resin layer, an intermediate layer, a second thermoplastic resin layer, and a second surface layer.
Laminates. The method of claim 1,
The thermoplastic resin impregnated with the continuous fiber to form the surface layer, the thermoplastic resin impregnated with the continuous fiber to form the intermediate layer, and the thermoplastic resin included in the thermoplastic resin layer are each independently polytetrafluoroethylene. PTFE, polyethylene, polypropylene, polystyrene, polyphenylene oxide (PPO), polyvinyl chloride (PVC), polyethylene terephthalate (PET) , Nylon 6.6, Polymethyl methacrylate (PMMA) and one selected from the group consisting of a combination thereof
Laminates. The method of claim 1,
Wherein the laminate has a flexural strength of 500 MPa to 700 MPa
Laminates. Impregnating a thermoplastic resin with a continuous fiber woven fabric comprising 1000 to 5000 fiber bundles to produce an intermediate layer;
Laminating a thermoplastic resin layer on at least one side of the intermediate layer;
Impregnating a thermoplastic resin with a continuous fiber-woven fabric comprising 10000 to 40,000 fiber bundles to produce at least one surface layer;
Laminating the surface layer on top of the at least one thermoplastic resin layer; And
Manufacturing a laminate by compression molding a laminate in which the intermediate layer, the at least one thermoplastic resin layer, and the at least one surface layer are laminated.
Method for producing a laminate comprising a. 14. The method of claim 13,
The compression molding is carried out after raising the temperature of the laminate to 250 to 300 캜
The manufacturing method of a laminated body. 14. The method of claim 13,
The compression molding is performed by raising the temperature of the compression molding mold to 90 to 150 캜
The manufacturing method of a laminated body. 14. The method of claim 13,
The compression molding is performed at a pressure of 1 MPa to 10 MPa
The manufacturing method of a laminated body. 14. The method of claim 13,
The surface layer and the intermediate layer are each prepared by stacking at least one sheet of prepreg form
The manufacturing method of a laminated body.

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