KR102169267B1 - Polyamide resin composition, and molded artice manufactured therefrom - Google Patents

Abstract

The present invention relates to a polyamide resin composition comprising a polyamide resin, a glass fiber, an inorganic reinforcing agent, and an impact resistant agent. The composition of the present invention, including inorganic reinforcing agents, has excellent noise-blocking properties, and has excellent strength, workability, and surface properties, and thus can be preferably applied to a cylinder head cover that covers an upper portion of an engine cylinder.

Description

Polyamide resin composition and plastic molded article manufacturing using the same {POLYAMIDE RESIN COMPOSITION, AND MOLDED ARTICE MANUFACTURED THEREFROM}

The present invention relates to a polyamide (Polyamide) resin composition and a plastic molded article using the same, and more specifically, a composition comprising a polyamide (PA) resin, glass fiber (Glass Fiber, GF), and an inorganic reinforcing agent, and the above It relates to a plastic resin composition made of the composition.

In the automobile manufacturing industry, in recent years, in addition to high performance, aesthetic interior and exterior designs are required. In accordance with the demand according to this trend, a lot of covers for various automobile parts are being developed. The roles of the covers are not only to make the appearance beautiful by covering the part's own external shape, but also to play a role of preventing the inherent noise generated by the part.

Representative of such a cover can be seen as the cylinder head cover of the engine. The cylinder head cover not only shows the engine room neatly and beautifully, but also has a function of sound-absorbing and sound-absorbing noise generated from the engine, and the demand is increasing.

In other words, the cylinder head cover for automobiles with the function of covering the upper part of the engine cylinder is used for the purpose of blocking or reducing noise from the engine and the neat appearance of the engine room. In the past, it was mainly applied only to expensive large vehicles. It is being applied to a freight car.

The characteristics required of the above-described engine cover material are that the cylinder head cover is installed around the engine, so it should have excellent mechanical properties, and because of its large size, the resin should have good flowability and good processability in terms of workability. This should be very good, and ultimately, the noise blocking effect should be good.

The plastic molded body, which is usually used as a cover for an engine, etc., is made of a composition in which glass fiber is applied to nylon or PET resin, but there is a disadvantage that physical properties and appearance characteristics are not sufficiently satisfied.

As a related technology, Korean Patent No. 0828654 proposes a technology in which glass bubbles are applied to improve mechanical properties of a glass fiber reinforced polyamide resin composition and prevent shrinkage, but a limitation in which the physical property conditions are not sufficiently satisfied was found.

Accordingly, an object of the present invention is to provide a polyamide resin having excellent tensile strength and flexural strength, and excellent noise-blocking function, and a molded article including the same, by preparing a polyamide resin composition comprising an inorganic reinforcing agent and glass fiber.

A first preferred embodiment according to the present invention comprises a polyamide resin, and comprises 40 to 100 parts by weight of glass fiber, and 5 to 30 parts by weight of an inorganic reinforcing agent, based on 100 parts by weight of the polyamide resin. It is a polyamide resin composition.

The polyamide resin according to the first embodiment may have a relative viscosity of 2.5 to 3.3, and a number average molecular weight of 20,000 to 50,000.

The glass fiber according to the first embodiment has a chopped shape, has a diameter of 8 to 15 μm, a length of 2 to 5.0 mm, and may be treated with a coupling treatment agent.

The composition according to the first embodiment may further include 0.01 to 10 parts by weight of an impact resistant agent, and the impact resistant agent may be grafted with maleic anhydride.

The specific gravity of the inorganic reinforcing agent according to the first embodiment may be 3.0 to 6.0.

The inorganic reinforcing agent according to the first embodiment may be one or more selected from the group consisting of barium sulfate, zinc oxide, zinc sulfide, titanium oxide, and iron oxide.

The inorganic reinforcing agent according to the first embodiment may be surface-treated with at least one organic functional group selected from the group consisting of a vinyl group, an epoxy group, a mercaptan group, and an amine group.

In addition, a second preferred embodiment according to the present invention is a plastic molded article comprising the polyamide resin composition.

The tensile strength of the molding according to the second embodiment is 1600kg/cm ² to 2300kg/cm ² , the flexural strength is 2500kg/cm ² to 3400kg/cm ² , and the impact strength is 90J/m to 300J/m. To do.

The polyamide resin composition according to the present invention can exhibit excellent noise-blocking properties while securing excellent mechanical properties, and thus can be applied to parts such as cylinder head covers for automobiles and engine room partition walls.

According to one aspect of the present invention, a polyamide resin comprising a polyamide resin, comprising 40 to 90 parts by weight of glass fibers, and 5 to 30 parts by weight of an inorganic reinforcing agent, based on 100 parts by weight of the polyamide resin. Compositions can be provided. In addition, it is possible to provide a plastic molded product comprising the polyamide resin composition.

In the present invention, by using barium sulfate, zinc oxide, titanium oxide, or iron oxide as an inorganic strengthening agent having a specific gravity of 3.0 to 6.0 and surface-treated with an organic functional group such as a vinyl group, an epoxy group, a mercaptan group, or an amine group, the present invention It is possible to obtain a noise-blocking effect of a molded product made of a polyamide resin.

In addition, the PBT/ASA alloy of the present invention has excellent physical properties and workability including glass fibers, and shows excellent impact strength by additionally including an impact resistant agent.

In addition, the polyamide resin composition, as a heat stabilizer, tetrakis(methylene(3,5-diteributyl-4-hydroxyhydrocinamate))methane, as a light stabilizer, within a range that does not impair the object of the present invention. Radical scavenger of the deteriorated amine system, N-phenylmaleimide/styrene copolymer as a compatibilizer, ethylene/propylene copolymer grafted with maleic anhydride as an impact resistance, or ethylene/octene copolymer grafted with maleic anhydride It may contain additionally.

1) Polyamide resin

The polyamide resin used in the present invention is polyamide 6, polyamide 12, polyamide 66, polyamide 6/66, polyamide 6/12, polyamide 6/6T, polyamide 6/6I, and copolymers thereof. It may be one or more selected from the group consisting of.

The polyamide resin may have a relative viscosity of 2.5 to 3.3. In this case, the relative viscosity of a solution obtained by adding 1 g of polyamide resin in 100 ml of 96% sulfuric acid at 20° C. with respect to 100 ml of 96% sulfuric acid at 20° C. It is the measured value of the relative viscosity.

If the relative viscosity of the polyamide resin is less than 2.5, excellent effects cannot be obtained in terms of improving stiffness and dimensional stability, and if it exceeds 3.3, surface defects and unmolding phenomena due to a decrease in fluidity may occur.

In addition, the number average molecular weight of the polyamide resin may be 20,000 to 50,000, and if the number average molecular weight is less than 20,000, there is a problem that the stiffness decreases, and if the number average molecular weight exceeds 50,000, the melt kneading is smooth due to poor flow due to high viscosity. You can't lose.

On the other hand, the polyamide resin of the present invention can be used after being sufficiently dried in a dehumidifying dryer by making it in a chip form for the production of the resin composition according to the present invention.

2) Glass fiber

The glass fiber according to the present invention has a chop shape, has a diameter of 8 to 15 μm, a length of 2 to 5.0 mm, and a surface treated with a coupling agent may be used.

When the diameter is less than 8 μm, the glass fibers are easily broken and insufficient to improve the rigidity. When the diameter exceeds 15 μm, it is not easily broken and the rigidity is improved, but excellent appearance quality cannot be obtained due to the problem of protruding on the surface.

In addition, when the length of the glass fiber is less than 2mm, it is insufficient to improve the rigidity due to the short length of the glass fiber, and when it exceeds 5mm, the rigidity is improved, but it is difficult to obtain excellent appearance quality due to the problem of protruding because the length is long. I can.

It is preferable to use a silane-based material having an organic functional group such as a vinyl group, an epoxy group, a mercaptan group, and an amine group as the coupling treatment agent.

In the present invention, the content of the glass fiber may be 40 to 100 parts by weight based on 100 parts by weight of the polyamide resin. When the content of the glass fiber is less than 40 parts by weight, the effect of imparting stiffness may be insignificant, and when the content of the glass fiber is more than 100 parts by weight, the glass fiber may protrude to the surface and the appearance quality may deteriorate. There may be a lot of warpage and distortion.

3) Mineral strengthening agent

In the present invention, the inorganic reinforcing agent may be used to improve the surface properties reinforcing effect and the noise blocking effect of the polyamide resin composition. In other words, in the present invention, glass fibers are used to reinforce the strength of the polyamide resin composition, but when only glass fibers are used, it is difficult to secure excellent surface properties due to glass fiber protrusion and flow marks on the surface, and noise blocking effect is improved. In order to make it possible to add inorganic reinforcing agents

The inorganic reinforcing agent is barium sulfate (BaSO ₄ ), zinc oxide (Zinc Oxide, ZnO), zinc sulfide (ZnS), titanium oxide (TiO ₂ ), iron oxide (Iron Oxide, Fe ₂ O). ₃ ) can be selected.

The inorganic reinforcing agent may be selected from those having a specific gravity of 3.0 to 6.0 or more. Those with a specific gravity of less than 3.0 are effective in improving the mechanical strength, but they are similar to the specific gravity of glass fiber (2.4~2.6) and have insignificant noise-blocking characteristics due to the effect of increasing the mass per unit area of the material. In the case of inorganic reinforcing agents with specific gravity exceeding 6.0, processability is poor when mixed with plastics due to high specific gravity, and is generally unsuitable for application as plastic reinforcing agents.

The reason for using the inorganic reinforcing agent having a relatively high specific gravity can be explained by the following equation for predicting the acoustic transmission loss as follows.

Mass Law : TL0 ∝ 20log( mf )

TL0 : Transmission loss, m: mass per unit area of material, f: frequency

The sound transmission loss can be seen as a degree of blocking noise. As in the above equation, when the mass per unit area of the material through which the sound passes is increased, the sound transmission loss increases, and thus the effect of blocking noise can be obtained.

By using an inorganic reinforcing agent having a high specific gravity in order to improve the performance of blocking noise by using an inorganic reinforcing agent, the weight per unit area of the resin composition can be increased, thereby improving the noise-blocking characteristics.

In addition, if it is only for strength reinforcement, it is necessary to increase the glass fiber content, but in that case, the surface characteristics and noise blocking characteristics are not good, so it can be used as an inorganic reinforcing agent to secure strength reinforcement and noise blocking characteristics.

The inorganic reinforcing agent may have a content of 5 to 30 parts by weight based on 100 parts by weight of the polyamide resin, and if the content of the inorganic particles is less than 5 parts by weight, there is a problem that the noise improvement effect by the inorganic reinforcing agent becomes insignificant. If it exceeds parts by weight, there is a problem in that the impact strength is lowered.

4) Impact resistance

The polyamide resin composition of the present invention may further include an impact resistance agent to secure impact resistance, and the impact resistance agent is an ethylene octene block copolymer grafted with maleic anhydride and an ethylene propylene block copolymer grafted with maleic anhydride. It may be one or more selected from the group consisting of polymers.

In addition, the content of the impact agent may be less than 10 parts by weight based on 100 parts by weight of the polyamide resin, and if the content of the impact agent exceeds 10 parts by weight, the impact strength may be improved, but the tensile strength and the flexural strength are lowered. As a result, it may be difficult to obtain an excellent product surface due to reduced flowability.

[Manufacturing method]

The polyamide resin composition according to the present invention can be prepared by extruding each component as described above, that is, a polyamide resin, a glass fiber, and an inorganic reinforcing agent in an extruder.

Specifically, the polyamide resin composition as described above may be kneaded at 240° C. to 280° C. for each component using a twin screw extruder to prepare a polyamide resin composition. At this time, in order to maximize the kneading of the polyamide resin composition, the polyamide resin is introduced into the primary inlet using an extruder having three inlets, but in some cases, it can be added together with an additive such as an impact resistant agent, and the secondary inlet Inorganic reinforcing agent particles can be added to and glass fibers can be added to the third inlet. In addition, the residence time can be minimized to prevent thermal decomposition of the polyamide resin composition during melt kneading, and the rotation of the screw can be adjusted to 150 ~ 800 rpm in consideration of the dispersibility of the polyamide resin composition.

As described above, the polyamide resin composition according to the present invention includes a polyamide resin, glass fiber, an inorganic reinforcing agent, and an impact resistance agent, and the polyamide resin composition maintains excellent tensile strength, flexural strength, flexural modulus and impact strength. While it has excellent noise blocking characteristics.

The polyamide resin composition ASTM evaluation method and the tensile strength due to D638 1600kg / cm ² to about 2300kg / cm ^2, the flexural strength according to ASTM evaluation method D790, and 2500kg / cm ² to about 3400kg / cm ² ASTM evaluation method D256 according to the invention It exhibits physical properties with an impact strength of 90J/m to 300 J/m, and can be applied as an automobile engine room part.

In particular, it is suitable as a material for manufacturing a cylinder head cover of a vehicle that requires both mechanical properties such as strength and noise-blocking properties.

Hereinafter, a preferred embodiment is presented to aid the understanding of the present invention. However, the following examples are provided for easier understanding of the present invention, and the contents of the present invention are not limited by the examples.

[ Example ]

Example One

Polyamide resin (Ascend's PA66 Vydyne 50BW), glass fiber (KCC's Glass Fiber CS311) and inorganic reinforcing agent (KOCH's KCB-8000 barium sulfate_specific gravity 4.5g/cc) at 280°C according to the composition shown in Table 1. A polyamide resin composition was prepared by melt-kneading in a twin-screw extruder heated by a furnace. The composition was made into a chip state and dried using a dehumidifying dryer at 100° C. for 4 hours, and a specimen including the polyamide resin composition was prepared at the same temperature as when melt-kneading using a screw injection machine.

Example 2

A specimen including a polyamide resin composition was prepared in the same manner as in Example 1, except that an impact resistant agent (PARALOID™ EXL-3808, manufactured by The Dow Chemical Company) was additionally used according to the content shown in Table 1.

Example 3

A specimen including a polyamide resin composition was prepared in the same manner as in Example 1, except that the inorganic reinforcing agent was additionally used according to the content shown in Table 1.

Example 4

A specimen including the polyamide resin composition was prepared in the same manner as in Example 1, except that glass fibers were additionally used according to the contents shown in Table 1.

Example 5 and Example 6

A specimen containing a polyamide resin composition was prepared in the same manner as in Example 1, except that the content of the inorganic reinforcing agent (Hanil Chemical Industry Co., Ltd. KS-1 zinc oxide_specific gravity 5.5 g/cc) was changed as shown in Table 1. Was produced.

Example 7

A specimen including a polyamide resin composition was prepared in the same manner as in Example 1 except that polyamide (PA6 KOPA KN111 manufactured by Kolon Plastics) was changed as described in Table 1.

Comparative example One, Comparative example 2 and Comparative example 3

A specimen including the polyamide resin composition was prepared in the same manner as in Example 1, except that the content of the inorganic strengthening agent was changed as described in Table 2.

Comparative example 4 and Comparative example 5

A specimen including the polyamide resin composition was prepared in the same manner as in Example 1, except that the glass fiber content was changed as described in Table 2.

Polyamide 66 ¹⁾ Polyamide 6 ²⁾ Glass fiber ³⁾ Mineral
Reinforcement 1 ⁴⁾ Mineral
Reinforcement 2 ^{5 )} Impact resistance ⁶⁾ Example 1 100 - 60 7 - - Example 2 100 - 60 7 - 5 Example 3 100 - 60 20 - - Example 4 100 - 90 7 - - Example 5 100 - 60 - 7 - Example 6 100 - 60 - 10 - Example 7 100 60 7 - - 1. Polyamide 66: Ascend's PA66 Vydyne50BW
2. Polyamide 6: PA6 KOPAKN111 from Kolon Plastics
3. Glass fiber: CS311 from KCC
4. Inorganic strengthening agent 1: KOCH KCB-8000 barium sulfate_specific gravity 4.5g/cc
5. Mineral strengthening agent 2: Hanil Chemical Industry KS-1 zinc oxide_ specific gravity 5.5g/cc
6. Impact resistance: TheDow Chemical Company, PARALOIDEXL-3808

Polyamide 66 ^{1 )} Fiberglass ^{2 )} Mineral reinforcement 1 ^{3 )}
Comparative Example 1 100 60 - Comparative Example 2 100 60 2 Comparative Example 3 100 60 45 Comparative Example 4 100 110 7 Comparative Example 5 100 20 7 1. Polyamide 66: Ascend's PA66 Vydyne 50BW
2. Glass fiber: CS311 of KCC
3. Inorganic reinforcing agent 1: KOCH KCB-8000 barium sulfate_specific gravity 4.5g/cc

Property evaluation

For the polyamide resin compositions prepared in Examples and Comparative Examples, tensile strength, flexural strength, impact strength, surface properties and noise barrier properties were measured in the following manner, and the results are shown in Table 3.

1) Tensile strength: According to ASTM evaluation method D 638, it was measured after producing a 1/8 inch specimen

2) Impact strength: A 1/8 inch specimen was manufactured according to ASTM D256, and the impact strength of Izod Notched was measured at room temperature and low temperature (-30℃).

3) Flexural strength: A 1/8 inch specimen was prepared and measured according to ASTM D790.

4) Surface flow mark: After melt-kneading the resin composition of the present invention in a chip state and dried for 5 hours at 90°C using a dehumidifying dryer, it is 350mm wide, 100mm long, and 3.0mm thick with a Nissei 170-ton injection molding machine. After fixing the injection temperature at 280℃ and the mold temperature at 80℃ by using a direct gate type square mold with a diameter of 7mm and a length of 80mm in the cavity, the first injection pressure is 1,100kg/cm2 without holding pressure. , Injection time 3 seconds, cooling time 15 seconds, among the molded products that were released, the flow mark in the gate area was observed with the naked eye.

5) Noise isolation measurement: Evaluation was conducted based on the evaluation method according to ISO 10847:1997(E). Noise generator, Octave band pass filter on the side of the noise source. After installing the loudspeaker and power amplifier equipment, build a sound insulation wall with a height of 3 m at a location of 1.5 m, and a noise signal of 500 to 3000 Hz from the noise source at a location 1.5 m higher than the height of the sound barrier at a distance of 3 m. The noise was measured while giving. After that, a noise reduction interference device was installed at the same height as the soundproof wall, and noise was measured at the same separation distance and height, and the difference in noise level was calculated by the formula below, and a difference of more than 4dB was considered good.

Noise level difference = (Noise when installing only soundproof walls)-(Noise when installing soundproof walls + noise reduction materials)

The tensile strength
(kgf/cm ² ) Flexural strength
(kgf/cm ² ) Impact strength
(J/m) Surface flow mark Noise level difference
(dB) Example 1 1910 2978 125 Good 5.4 Example 2 1850 2684 176 Good 5.3 Example 3 1967 3141 135 Good 5.7 Example 4 2013 3204 165 Good 6.2 Example 5 1849 2531 101 Good 5.7 Example 6 1990 3018 125 Good 6.1 Example 7 1905 2832 115 Good 5.1

The tensile strength
(kgf/cm ² ) Flexural strength
(kgf/cm ² ) Impact strength
(J/M) Surface flow mark Noise level difference
(dB) Comparative Example 1 1922 2762 114 Good 3.1 Comparative Example 2 1977 2884 126 Good 3.2 Comparative Example 3 1456 2258 84 Good 5.9 Comparative Example 4 2289 3650 260 Bad 5.1 Comparative Example 5 1407 2063 64 Good 2.8

As a result of the physical property evaluation, as shown in Table 3, the polyamide resin composition prepared by using the polyamide resin, glass fiber, inorganic reinforcing agent and impact resistant agent in an appropriate composition has tensile strength, flexural strength, impact strength, noise barrier properties, and It has excellent surface characteristics, and in particular, it can be confirmed that it can be applied to the cylinder head cover material, which is a component around an automobile engine.

However, as shown in Table 4, when preparing the polyamide resin composition, when the content of the inorganic reinforcing agent was low, the noise blocking effect was low (Comparative Examples 1 and 2).

In addition, when preparing the polyamide resin composition, when the content of the inorganic reinforcing agent is high, the noise-blocking properties are excellent, but the mechanical strength is low (Comparative Example 3).

In addition, when the content of glass fiber in the polyamide resin composition exceeds the appropriate content, the tensile strength and flexural strength are improved, but the surface of the product is not good and does not come out as much as the desired level (Comparative Example 4), and the content of glass fiber is appropriate. If it is less than the tensile strength, flexural strength, and flexural modulus rather than desired, it was found that the noise-blocking properties were also degraded (Comparative Example 5).

As the specific parts of the present invention have been described in detail above, it will be apparent to those of ordinary skill in the art that these specific descriptions are only preferred embodiments, and the scope of the present invention is not limited thereby. will be. Accordingly, it will be said that the substantial scope of the present invention is defined by the appended claims and their equivalents.

Claims (9)

A polyamide resin composition comprising a polyamide resin, comprising 40 to 100 parts by weight of glass fibers and 5 to 30 parts by weight of barium sulfate as an inorganic reinforcing agent based on 100 parts by weight of the polyamide resin.
The method of claim 1,
The polyamide resin composition, wherein the polyamide resin has a relative viscosity of 2.5 to 3.3 and a number average molecular weight of 20,000 to 50,000.
The method of claim 1,
The glass fiber has a chopped shape, has a diameter of 8 to 15 μm, a length of 2.0 to 5.0 mm, and is treated with a coupling treatment agent.
The method of claim 1,
The composition further comprises 0.01 to 10 parts by weight of an impact resistant agent, wherein the impact resistant agent is grafted with maleic anhydride.
The method of claim 1,
The specific gravity of the barium sulfate is 3.0 to 6.0, characterized in that the polyamide resin composition.
delete The method of claim 1,
The barium sulfate is a polyamide resin composition, characterized in that the surface-treated with at least one organic functional group selected from the group consisting of a vinyl group, an epoxy group, a mercaptan group, and an amine group.
A plastic molded article comprising the polyamide resin composition of any one of claims 1 to 5 and 7.
The method of claim 8,
The tensile strength of the molding is 1600kg/cm ² to 2300kg/cm ² , the flexural strength is 2500 kg/cm ² to 3400 kg/cm ² , and the impact strength is 90 J/m to 300 J/m. , Plastic moldings.