KR20170039013A - Long Fiber Reinforced Thermoplastics Resin Composition And Article Manufactured By Using The Same - Google Patents

Abstract

The present invention relates to a long fiber reinforced thermoplastic resin composition and a long fiber reinforced foamed product. The long fiber reinforced thermoplastic resin composition comprises: a polyamide-based resin having relative viscosity of 2.4 to 3.0; a resin for impregnation having an ASTM D1238 measurement standard melt index (MI) of 60 to 150 g/10 minutes (230 C, load 2.16 kg); and reinforcement fibers having the length of 5 to 50 mm and the average diameter of 5 to 30 m.

Description

TECHNICAL FIELD [0001] The present invention relates to a long fiber-reinforced thermoplastic resin composition and a molded article using the same. [0002]

The present invention relates to a long fiber-reinforced thermoplastic resin composition and a molded article produced using the same, and more particularly to a long fiber-reinforced polyamide-based composition capable of exhibiting excellent physical properties in the production of a molded article and a molded article will be.

Composite refers to a material that artificially mixes or binds materials with different components and properties to maximize the properties of each material or to have new properties that are not expressed in a single material. Composite materials are basically excellent in properties such as strength, corrosion resistance, fatigue life, abrasion resistance, impact resistance, and light weight compared to conventional materials. Therefore, they are widely used in aerospace, sports goods, shipbuilding, It is a representative 21st century industrial material that is attracting attention in the field.

The composite material is generally made of a reinforced material that is responsible for the load applied to the material, and a matrix that transmits the load to the reinforcement in combination with the reinforcement. The reinforcing material is usually glass fiber, carbon fiber, aramid A variety of fibrous reinforcing materials such as polyolefins, polyolefins, polyolefins, polyolefins, polyolefins, polyolefins, polyolefins, polyolefins, polyolefins, Resin-based base materials such as thermosetting resins including phenol sulfide and phenol sulfide are widely used.

Such a composite material is classified into various types depending on which materials are combined with each other. Fiber reinforced composite materials in which a fiber reinforcing material such as glass fiber is mixed with a resin so as to improve the mechanical strength of the resin product are most widely manufactured. Such fiber-reinforced composite materials can be classified into short-fiber reinforced resin and long-fiber reinforced thermoplastics (LFT).

The short-fiber-reinforced resin has a short fiber length of 0.5 mm or less so that it can be easily dispersed in the resin and the short fibers are evenly distributed to the end of the molded article. However, it is difficult to obtain sufficient strength for applications requiring a large load. On the other hand, the long fiber reinforced resin produced by the pultrusion method has advantages such as the recyclability and easiness of molding and the mechanical properties and the heat resistance by themselves, and thus it is used throughout the industry such as household appliances and building materials, The use of automobiles in the automobile industry, which requires recycling characteristics, is expanding.

In Korean Patent Laid-Open Publication No. 2013-0135519, the mechanical properties such as flexural modulus, tensile strength and impact strength are increased by impregnating property between the polyolefin-based resin composition and the glass fiber and by increasing the campatility Which can reduce the weight of parts by reducing the amount of glass fibers. Korean Patent No. 0653601 discloses a colored fiber-reinforced polyolefin-based molded article excellent in mechanical properties such as impact strength, tensile strength and flexural strength and excellent in heat resistance, a long fiber-reinforced polyolefin-based composition for producing the same, A manufacturing method thereof has been disclosed.

As described above, the most widely used material in the field of LFT production is a polyolefin-based long-fiber reinforced resin having excellent mechanical strength. However, the polyolefin-based long-fiber reinforced resin is a general-purpose resin and has a limitation in that there is a limitation in use depending on the application. Therefore, a material satisfying both mechanical properties and heat resistance is required.

On the other hand, the impregnation property and the impregnation content of the resin on the fiber greatly affect the physical properties of the final product in the production of the molded product of the fiber reinforced composite material by the draw-forming. In particular, the lack of impregnation uniformity of the resin and thus the residual of non-impregnated interstices such as voids can act as a cause of defects in the mechanical properties of the final product, which increases the number and content of supplied fibers, , The more the final product is massed, the more remarkable it becomes.

Therefore, it is an important factor in improving the physical properties of the LFT that the resin is well dispersed when the reinforcing fiber is impregnated into the resin, so that the resin is permeated into all portions of the fiber and uniform impregnation to the inside of the fiber can be achieved.

Accordingly, it is an object of the present invention to provide a long fiber-reinforced resin composition which is excellent in heat resistance and mechanical strength, and which is excellent in impregnation property and can exhibit improved physical properties.

A first embodiment of the present invention for solving the above problems is a polyimide resin having a relative viscosity of 2.4 to 3.0 and having a melt index (MI) of 60 to 150 g / 10 min (ASTM D1238) Lt; 0 > C, load: 2.16 kg); And reinforcing fibers having a length of 5 to 50 mm and an average diameter of 5 to 30 占 퐉.

The impregnating resin according to the first embodiment may include 1 to 5 parts by weight of a flow improver based on 100 parts by weight of a polyamide resin. The flow improver may include CBT (Cyclo Butylene Terephtalate), Fatty acid A wax, a silicone compound, a hyperbranched material, and a dendrimer.

The content of the reinforcing fiber according to the first embodiment may be 80 to 120 parts by weight based on 100 parts by weight of the polyamide resin.

Meanwhile, the polyamide resin according to the first embodiment may be at least one selected from the group consisting of polyamide 6, polyamide 66, polyamide 46, polyamide 610, polyamide 612, polyamide 11 and polyamide 12, The fibers for use in the present invention include glass fiber, carbon fiber, graphite fiber, metal fiber, basalt fiber, cotton fiber, wool fiber, silk fiber, aramid fiber, PE fiber, PAN fiber, arylate fiber, PEEK fiber nylon fiber, And mixed fibers.

The long fiber-reinforced thermoplastic resin composition according to the first embodiment may have a spiral flow length of 940 mm or more measured at a mold temperature of 80 캜, a cylinder temperature of 310 캜, an injection speed of 100 mm / s, and an injection pressure of 40 bar.

Further, the present invention can be achieved by at least one method selected from injection molding, extrusion molding, compression molding, insert injection molding, low pressure injection molding, foam injection molding and foam extrusion molding using the long fiber-reinforced thermoplastic resin composition of the first embodiment The formed long fiber-reinforced molded article is a second embodiment.

The long fiber reinforced molded product according to the second embodiment may satisfy the tensile strength of 270 MPa or more according to ASTM D638, flexural modulus of 13,800 MPa or more according to ASTM D790 standard, and IZOD impact strength of 325 J / m or more according to ASTM D256 standard .

According to the present invention, since the flowability of the resin is improved, the impregnating resin can be uniformly impregnated between the bundles of reinforcing fibers. As a result, when a molded article is produced by using the long fiber-reinforced resin composition of the present invention, tensile strength, , Mechanical strength such as impact strength and the like can be greatly improved. As a result, it can be expected to be used as a reinforcing material in the automobile industry and various industrial fields by replacing expensive reinforced super engineering plastics.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a SEM photograph showing the resin-impregnated state of the reinforcing fibers of Example 1 and Comparative Example 1 of the present invention. FIG.

The present invention relates to an impregnating resin comprising a polyamide resin having a relative viscosity of 2.4 to 3.0 and having a melt index (MI) of 60 to 150 g / 10 min (230 DEG C, load 2.16 kg) according to ASTM D1238 measurement standard; And reinforcing fibers having a length of 5 to 50 mm and an average diameter of 5 to 30 占 퐉.

The melt index of the present invention means the flow rate when a melt is extruded from a piston under a predetermined constant condition, and means an index indicating easiness of flow of the melt. In the present invention, the melt index can be measured on the basis of a load of 21.6 kg at 230 DEG C according to ASTM D1238, and it can be judged that the larger the index value, the better the flowability. That is, considering that the melt index of the polyamide-based resin is 20 to 30 in general under the same conditions, the impregnation resin of the present invention has a melt index of 60 to 150 g / 10 min (230 DEG C, load of 2.16 kg) The flowability of the impregnation resin of the present invention is remarkably superior to that of a general polyamide-based resin.

In the present invention, the impregnating resin is improved in melt index by a flow improver. In this case, the impregnating resin preferably comprises 1 to 5 parts by weight of a flow improver based on 100 parts by weight of the polyamide based resin. If the content of the flow improver is less than 1 part by weight based on 100 parts by weight of the polyamide based resin, the improvement of the melt index is insignificant. If the content of the flow improver exceeds 5 parts by weight, the flowability is excessively improved. In addition, if a flow improver is used, gas may be generated, so care must be taken to minimize the effect of the gas on the process.

In the present invention, the flow improver may be at least one selected from CBT (Cyclo Butylene Terephtalate), Fatty acid, polypropylene wax, silicone compound, hyperbranched material, and dendrimer Such an improving agent is positioned between the polymer chains in the molecular structure to increase the distance between the polymer chains to weaken the hydrogen bonding force, thereby improving the flowability of the impregnating resin. Among the flow improvers, at least one selected from CBT, a hyperbranched polymer and a dendrimer may be more preferable, and CBT may be particularly preferable among them.

In the present invention, the polyamide-based resin has a weight average molecular weight of 20,000 to 50,000 as measured by gel permeation chromatography (GPC), and is measured based on the addition of 1 g of polyamide resin to 100 ml of 96% sulfuric acid at 20 ° C It is preferable that the relative viscosity is 2.4 to 3.0. If the relative viscosity is less than 2.4, the mechanical properties of the resin are too low, and if the relative viscosity exceeds 3.0, the impregnation property between the resin and the glass fiber may deteriorate and the physical properties may be inadequate.

The polyamide-based resin may be at least one selected from the group consisting of polyamide 6, polyamide 66, polyamide 46, polyamide 610, polyamide 612, polyamide 11, polyamide 12, In order to further improve the mechanical properties and heat resistance of the fiber-reinforced composite material, it is more preferable to use at least two of the polyamide-based resins as an alloy. When two or more kinds of resins are used as the alloy, it may be preferable to select polyamide 66 and polyamide 46 having a melting point difference within 30 to 40 ° C, and the mixing ratio may be a weight ratio of 75 to 90:10 to 25 But are not necessarily limited thereto.

In the present invention, it is preferable that the reinforcing fibers have a length of 5 to 50 mm and an average diameter of 5 to 30 탆. When the length of the reinforcing fiber is less than 5 mm, it exhibits the characteristics of the short fiber. Therefore, it is difficult to obtain sufficient strength for applications requiring a large load, while when it exceeds 50 mm, molding is not preferable. If the diameter is less than 5 mu m, the number of fibers existing per unit area increases, and the penetration of the resin into the spaces between the fibers is not free and the impregnability is lowered. When the diameter exceeds 30 mu m, L / D is relatively decreased, It may be unsuitable for improvement of physical properties.

The reinforcement fiber may be contained in an amount of 80 to 120 parts by weight based on 100 parts by weight of the polyamide resin. If the content of the reinforcing fiber is less than 80 parts by weight based on 100 parts by weight of the polyamide based resin, high physical properties can not be exhibited. If the content of the reinforcing fibers exceeds 120 parts by weight, the amount of the resin is relatively small, There is a possibility that the fibers are exposed to the surface.

In the present invention, the reinforcing fibers may be glass fibers, carbon fibers, graphite fibers, metal fibers, basalt fibers, cotton fibers, wool fibers, silk fibers, aramid fibers, PE fibers, PAN fibers, , PET fibers, and mixed fibers thereof, and more preferably at least one selected from glass fibers, carbon fibers, aramid fibers, and mixed fibers thereof.

As a result, the flowability of the long fiber-reinforced thermoplastic resin composition of the present invention can be improved as compared with the case of using only a polymer resin as the impregnation resin. Quantitatively, the mold temperature is 80 ° C, the cylinder temperature is 310 ° C, s and injection pressure of 40 bar can satisfy the spiral flow length of 940 mm or more. In this case, if the spiral flow length is less than 940 mm, the spiral flow takes a long time to produce the molded article, and it causes the non-molding, and the increase of the residence time It may cause decomposition of the resin and may deteriorate the physical properties.

Further, the present invention is characterized in that the above-mentioned long fiber-reinforced thermoplastic resin composition is molded by at least one method selected from injection molding, extrusion molding, compression molding, insert injection molding, low pressure injection molding, foam injection molding and foam extrusion molding, And can be produced as a molded product.

Since the long fiber-reinforced molded product thus manufactured satisfies the tensile strength of 270 MPa or more as measured by ASTM D638, the flexural modulus of 13,800 MPa or more as measured by ASTM D790 and the IZOD impact strength of 325 J / m or more as measured by ASTM D256, It can be used as a reinforcing material in automobile industry and various industrial fields with excellent abrasion resistance, and it can be expected to be utilized as a material capable of replacing reinforced super engineering resin, among other things.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are for the purpose of illustrating the present invention more specifically, and the present invention is not limited thereto.

Example 1

100 parts by weight of a polyamide 66 resin (relative viscosity 2.7, Ascend) and 1 part by weight of a flow improver (CBT100, cyclic corporation) were mixed by melt mixing to prepare a resin for impregnation, , And impregnated with 100 parts by weight of continuous glass fiber reinforcement (OCV) having a diameter of 10 탆 to prepare 10 mm polyamide-based long-fiber reinforced pellets. At this time, the MI (melt index) measured by the ASTM D1238 measurement method before transferring the impregnating resin to the impregnation die was 60 g / 10 min.

Example 2

Polyamide-based long fiber reinforced pellets were prepared in the same manner as in Example 1, except that 3 parts by weight of a flow improver (CBT100, Cyclic corporation) was melt-mixed to prepare impregnation resin (MI = 108 g / 10 min).

Example 3

Polyamide-based long fiber reinforced pellets were prepared in the same manner as in Example 1, except that 5 parts by weight of a flow improver (CBT100, Cyclic corporation) was melt-mixed to prepare impregnation resin (MI = 135 g / 10 min).

Comparative Example 1

Reinforced pellets were produced in the same manner as in Example 1 except that polyamide 66 resin (relative viscosity: 2.7, Ascend) was used as impregnation resin (MI = 50 g / 10 min) Respectively.

Comparative Examples 2, 3, 4 to 5

Using the impregnating resins of Examples 1 to 3 and Comparative Example 1, the length of the pellets was changed to 3 mm, and the polyamide-based short fiber reinforced materials of Comparative Example 2, Comparative Example 3, Comparative Example 4 and Comparative Example 5 Pellets were prepared.

<Measurement example 1>

Next, to indirectly measure the interfacial adhesion between the fibers and the resin, the pellets prepared in the above Examples and Comparative Examples were dried at 80 DEG C for 5 hours and then put into a stirrer mixer at a speed of 5000 rpm, (Weight loss before and after stirring was not so great as the interfacial adhesion was excellent). In addition, Example 1 and Comparative Example 1 were extracted from the above Examples and Comparative Examples, and the degree of impregnation was more specifically confirmed by SEM (Scanning Electron Microscopy, see FIG. 1).

PA66
(Parts by weight) flow
Improvement agent
(Parts by weight) LGF
(10 mm) SGF
(3 mm) Early
weight Weight after agitation Reduction amount
(%) Example 1 100 One 100 - 20 g 18.2 g 9.0 Example 2 100 3 100 - 20 g 19.2 g 4.0 Example 3 100 5 100 - 20 g 18.8 g 6.0 Comparative Example 1 100 - 100 - 20 g 17.5 g 12.5 Comparative Example 2 100 One - 100 20 g 19.4 g 3.0 Comparative Example 3 100 3 - 100 20 g 19.5 g 2.5 Comparative Example 4 100 5 - 100 20 g 19.4 g 3.0 Comparative Example 5 100 - - 100 20 g 19.2 g 4.0

As can be seen from Table 1, Comparative Examples 2 to 5 using short fibers showed a small weight reduction regardless of the addition amount of the flow improver, because they are less likely to collide with blender blades than short fibers in terms of short fiber properties. On the other hand, Examples 1 to 3, in which long fibers were used as reinforcing fibers, showed a larger amount of decrease than Comparative Examples 2 to 5, but had higher interfacial adhesion between fibers and resin than Comparative Example 1, And the decrease rate was relatively low.

As can be seen from FIG. 1, in the SEM photograph of Example 1 in which the flow improver was added, it was confirmed that the resin was well penetrated between the fibers to impregnate the fibers. In the SEM photograph of Comparative Example 1, Can be confirmed.

<Measurement example 2>

Meanwhile, pellets prepared from the above examples and comparative examples were prepared as test specimens according to ASTM test standards using an injection machine with a mold clamping force of 170 tons. After 48 hours at room temperature, physical properties and flow properties were measured under the following conditions.

1) Tensile strength: Measured by the method according to ASTM D638.

2) Flexural strength: Measured according to ASTM D790

3) Flexural modulus: Measured according to ASTM D790

4) Impact strength: Measured according to ASTM D256

5) Heat distortion temperature: Measured according to ASTM D648

6) Flow rate evaluation (Kolon plastic self-evaluation standard): PRO 170 MC model manufactured by Dongshin Hydraulic Co., Ltd. was used. Mold temperature 80 ℃, cylinder temperature 310 ℃, injection speed Max speed 100 mm / s, injection pressure 40 bar, the width of the injection 4 mm, and the thickness of the injection molding 2.5 mm (Half-round).

Ten specimens were evaluated for each of the above properties, and the average value thereof was reflected in the following Table 2 as a result.

The tensile strength
(MPa) Flexural strength
(MPa) curve
Modulus of elasticity
(MPa) IZOD
Impact strength
(J / m) Thermal deformation
Temperature (℃) Spiral
Flow length (mm) Example 1 283 348 13,940 338 259 941 Example 2 312 377 14,180 350 259 956 Example 3 297 364 14,080 342 259 976 Comparative Example 1 254 315 13,710 315 259 923 Comparative Example 2 210 288 13,360 294 256 1039 Comparative Example 3 231 305 13,680 306 257 1054 Comparative Example 4 224 295 13,460 296 257 1011 Comparative Example 5 203 277 13,120 292 256 1028

As can be seen from the above physical properties results, even when the length of the spiral flow is lower than that of the specimen using the short fiber reinforced pellets of Examples 1, 2 and 3, which is the short fiber reinforced pellets of Comparative Examples 2, 3, 4 and 5 However, it has been confirmed that it shows superior characteristics in terms of mechanical properties. In addition, the comparative example 1 in which the flow improver was not added in spite of the long fiber reinforced pellets showed that the mechanical properties were not sufficiently realized because the spiral flow length was relatively short as compared with Examples 1 to 3.

Claims (9)

An impregnating resin containing a polyamide resin having a relative viscosity of 2.4 to 3.0 and having a melt index (MI) of 60 to 150 g / 10 min (230 DEG C, load 2.16 kg) as measured by ASTM D1238; And reinforcing fibers having a length of 5 to 50 mm and an average diameter of 5 to 30 占 퐉.
The long fiber-reinforced thermoplastic resin composition according to claim 1, wherein the impregnating resin comprises 1 to 5 parts by weight of a flow improver based on 100 parts by weight of the polyamide resin.
The flow improver according to claim 2, wherein the flow improver is at least one selected from CBT (Cyclo Butylene Terephthalate), Fatty acid, Wax, silicone compound, hyperbranched material, and Dendrimer Wherein the long fiber-reinforced thermoplastic resin composition is a thermoplastic resin composition.
The long-fiber-reinforced thermoplastic resin composition according to claim 1, wherein the content of the reinforcing fiber is 80 to 120 parts by weight based on 100 parts by weight of the polyamide-based resin.
The polyamide-based resin according to claim 1, wherein the polyamide-based resin is at least one selected from the group consisting of polyamide 6, polyamide 66, polyamide 46, polyamide 610, polyamide 612, polyamide 11, Reinforced thermoplastic resin composition.
The reinforcing fiber according to claim 1, wherein the reinforcing fiber is selected from the group consisting of glass fiber, carbon fiber, graphite fiber, metal fiber, basalt fiber, cotton fiber, wool fiber, silk fiber, aramid fiber, PE fiber, Nylon fiber, PET fiber, and a mixed fiber thereof. The long-fiber-reinforced thermoplastic resin composition according to claim 1,
The long fiber-reinforced thermoplastic resin composition according to claim 1, wherein the spiral flow length measured at a mold temperature of 80 캜, a cylinder temperature of 310 캜, an injection speed of 100 mm / s and an injection pressure of 40 bar is not less than 940 mm / RTI &gt; thermoplastic composition.
At least one method selected from injection molding, extrusion molding, compression molding, insert injection molding, low pressure injection molding, foam injection molding and foam extrusion molding using the long fiber reinforced thermoplastic resin composition of any one of claims 1 to 7 A long fiber reinforced molded product.
The long fiber reinforced molded product according to claim 8, wherein the long fiber reinforced molded product satisfies a tensile strength of 270 MPa or more as measured by ASTM D638, a flexural modulus of 13,800 MPa or more as measured by ASTM D790, and an IZOD impact strength of 325 J / m or more as measured by ASTM D256 Long fiber reinforced molded products.

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