KR102468855B1 - Polyamid resin composition and Molding produced from the same - Google Patents

Abstract

The present invention relates to a polyamide resin composition, and more particularly, to a technology used for automobile engine parts requiring excellent overall mechanical properties, fluidity, and heat resistance of a product, and particularly excellent NVH characteristics, and specifically, It is about the cylinder head cover.

Description

Polyamide resin composition and molded products manufactured therefrom {Polyamid resin composition and Molding produced from the same}

The present invention relates to a polyamide resin composition and a molded article made therefrom.

The cylinder head cover for automobiles, which covers the upper part of the engine cylinder, is used for the neat appearance of the engine room and for the purpose of blocking or reducing noise from the engine. It is being applied and is being applied to trucks as well. Since the cylinder head cover, which is an engine part material described above, is mounted around the engine, it must have excellent mechanical properties by default, and because of its large size, it must have good processability due to good fluidity of the resin in terms of workability, surface characteristics are very good, Ultimately, the noise blocking effect must be excellent.

As a related technology, Japanese Patent Application Laid-open Publication No. 5817440 proposed a technology using calcium oxide (CaO) and magnesium oxide (MgO) for surface improvement, and Japanese Patent Laid-Open No. 59-133249 also proposed glass fiber to improve fluidity and tensile properties. and a plasticizer were added to present a composition with excellent appearance. US 4613647 proposed a technology of introducing aromatic polyamide while reinforcing polyamide resin with glass fibers to improve heat resistance properties, and US 3843591 proposed a coupling agent that enhances interfacial adhesion between inorganic materials to improve heat resistance and mechanical properties. was introduced. Japanese Patent Laid-Open No. 60-108463 and Japanese Unexamined Patent No. 60-47061 suggest a technique for improving stiffness and heat resistance by adding clay and glass fibers surface-treated with a silane coupling agent to polyamide, and Japanese Patent Laid-Open No. 42-47061 12546, Japanese Patent Laid-open Publication No. 45-30945 also showed a technology for combining and applying polyamide and polypropylene resin using a compatibilizer for parts around automobile engines. In particular, Korean Unexamined Patent Publication No. 2001-0103194 and Korean Unexamined Patent Publication No. 2002-0056066 are advantageous to polyamide as a technology applied with nanoclay to improve the light weight and mechanical properties of glass fiber-reinforced polyamide resin composition and as a damping material for automobile engine covers for reducing noise. Techniques using fibers and mica were also presented.

Korean Registered Patent No. 0828654 suggested a technology using glass bubbles to improve mechanical properties and prevent shrinkage of a glass fiber-reinforced polyamide resin composition, but it was found that the physical property conditions were not sufficiently satisfied.

The present invention is to provide a polyamide resin composition that reduces radiated noise of engine plastic cover parts through the development of a polymer material with improved vibration damping performance, and a molded article manufactured therefrom.

One embodiment of the present invention comprises a polyamide resin, based on 100 parts by weight of the polyamide resin, 70 to 111 parts by weight of glass fiber, 9 to 16 parts by weight of a carbon-based reinforcing agent, and 25 to 16 parts by weight of a damping ratio improving additive It is to provide a polyamide resin composition comprising 100.

The polyamide resin may have a relative viscosity of 2.0 to 3.5 and a number average molecular weight of 20,000 to 50,000.

The glass fiber may have a chopped shape, have a diameter of 8 to 15 μm, have a length of 2.0 to 5.0 mm, and be treated with a coupling treatment agent.

Based on 100 parts by weight of the polyamide resin, 9 to 16 parts by weight of a carbon-based reinforcing agent surface-treated with a coupling agent may be further included.

The damping ratio improving additive may have a glass transition temperature of 100 to 250 °C.

The damping ratio improving additive is polyphthalamide (PPA), polyester sulfone (PES), polyetheramide (PEI), polyphenylene sulfide (PPS), polyphenyl ether (PPE), polyether ether ketone (PEEK), It can be characterized by including at least one selected from the group consisting of ketones and polyimides (PI).

Another embodiment of the present invention is to provide a molded article manufactured from the polyamide resin composition described above.

The molded article has a tensile strength of 200 Mpa to 220 Mpa according to the ISO evaluation method ISO 527, a flexural strength of 285 Mpa to 300 Mpa according to ISO 178, a flexural modulus of 10600 Mpa to 13000 Mpa according to ISO 178, and a damping ratio (tan δ) of 0.1 to 0.35. that can be characterized.

When the polyamide resin composition according to the present invention and a molded product manufactured therefrom are applied to a cylinder head cover or a timing belt/chain cover of an engine, an effect of reducing the size of noise can be obtained by suppressing the degree of change to radiated sound.

The present invention relates to a polyamide resin composition, and more particularly, to a technology used for automobile engine parts requiring excellent overall mechanical properties, fluidity, heat resistance and particularly excellent NVH properties, and specifically, It is about the cylinder head cover.

This technology replaces nylon 6,6 material reinforced with glass fiber, which was used as a material for cylinder head cover, timing belt cover, and oil pan, which are parts of conventional engine plastic covers, with nylon 6 to replace conventional nylon 6,6 material It is an invention that can reduce engine radiated noise by securing mechanical strength and heat resistance and improving vibration damping ability compared to various covers of . When the engine is running, vibration is generated by the up-and-down movement of the piston in the cylinder and the rotational movement of the crankshaft, so radiation is generated by the vibration transmitted to the surface of the part. change in shape As various technologies are applied to increase power and torque while reducing the size of the engine compared to the past, engine vibration tends to become more intense, and accordingly, the size of noise caused by vibration is further increased. In order to improve this problem, the damping ratio was improved by improving the rheological behavior of the material to improve the vibration damping ability of the conventionally applied glass fiber reinforced nylon 6,6 material, and at the same time, to improve the modulus, the carbon based reinforcing agent was used. Plastic engine parts manufactured using materials applied with this technology reduce the amount of noise by suppressing the degree of change to radiated sound by attenuating the size of vibration when the vibration generated from the movement of the piston and crankshaft is transmitted to the plastic parts. effect can be obtained.

In order to improve the level of vibration damping performance of plastic polymers previously developed as materials for engine cylinder head covers, timing belt/chain covers, and oil pans, the rheological properties of the applied resins have been changed, which is known as the damping ratio of the materials. ) to improve.

According to one embodiment of the present invention, based on 100 parts by weight of nylon 6 (Polyamide 6) resin having excellent heat resistance and mechanical strength, in order to impart mechanical strength, a chop shape having a diameter of 8 to 15 μm and a length of 2 70 to 111 parts by weight of glass fibers of ~5.0 mm were used, and additives for improving damping properties and damping ratio of resin were 25 parts by weight. to 100 parts by weight, and 9 to 16 parts by weight of the carbon-based reinforcing agent for improving the modulus of the resin may be provided.

Hereinafter, the present invention will be described in detail.

[A] Polyamide resin

In the composition of the present invention, the polyamide 6 resin preferably used has a relative viscosity of 2.0 to 3.5 (a solution of 1 g of polyamide 6 resin in 100 ml of 96% sulfuric acid at 20°C). At this time, if the relative viscosity of the polyamide 6 resin is less than 2.0, the stiffness, impact strength and heat resistance are lowered, and if it exceeds 3.5, excessive frictional heat occurs between the screw and the resin in the molding machine, the resin is decomposed, or high pressure is applied for molding. As this is necessary, there is a problem in that injection molding is difficult by generating a bunch in the molding machine and the mold.

In addition, the number average molecular weight of the polyamide 6 resin may be 20000 to 50000, and if the number average molecular weight is less than 20000, there is a problem in that rigidity is lowered, and if it is more than 50000, flowability is not good due to high viscosity, which causes problems during melt kneading. can happen Meanwhile, the polyamide resin of the present invention may be used after being made into a chip form and sufficiently dried in a dehumidifying dryer to prepare the resin composition according to the present invention.

[B] Glass fiber

The glass fiber according to the present invention is in the form of a chop, 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. Additionally, a silane-based coupling agent can be added. When the diameter of the glass fiber is less than 8 μm, the glass fiber is easily broken and insufficient to improve the rigidity. When the diameter exceeds 15 μm, the glass fiber is not easily broken and the stiffness is improved. can't In addition, when the length of the glass fiber is less than 2 mm, it is insufficient to improve the rigidity due to the short length of the glass fiber, and when the length exceeds 5 mm, the rigidity is improved, but due to the protruding problem due to the long length, excellent appearance quality cannot be obtained .

In the present invention, the content of the glass fiber may be 70 to 111 parts by weight based on 100 parts by weight of the polyamide resin. If the content of the glass fiber is less than 70 parts by weight, the effect of imparting stiffness may be insignificant, and if the content of the glass fiber is greater than 111 parts by weight, the glass fiber protrudes to the surface and the appearance quality may deteriorate. A lot of bending and twisting can occur.

[C] carbon system enhancer

In the present invention, the carbon-based reinforcing agent may be used to improve the modulus reinforcing effect and NVH (Noise Vibration Hashness) effect of the polyamide resin composition.

That is, in the present invention, glass fibers are used to reinforce the strength of the polyamide resin composition, but when only glass fibers are used, there is a limit to improving the modulus, so the NVH effect on vibration may be lower than when a carbon-based reinforcing agent is not used. A carbon-based reinforcing agent may be added.

The carbon-based reinforcing agent may be selected from Polyurethane, Epoxy, PI, Phenolic 1mm, 3mm, and 6mm depending on the type of coupling agent.

The reason for using the carbon-based reinforcing agent can be explained by taking the following formula expected as follows.

<Equation 1>

Since the vibration applied to the part, that is, NVH, increases the natural frequency at which the material can change as the stiffness of the material increases, the higher the stiffness (modulus) of the material, the higher the NVH characteristics.

Therefore, a carbon-based reinforcing agent was applied to improve the modulus.

The carbon-based reinforcing agent may have a content of 9 to 16 parts by weight based on 100 parts by weight of the polyamide resin, and if the content of the inorganic particles is less than 9 parts by weight, there is a problem in that the modulus is reduced, and if it exceeds 16 parts by weight, the cost is increased. There is an escalating problem.

In addition, the composition according to the present invention may further include 9 to 16 parts by weight of a carbon-based reinforcing agent surface-treated with a coupling treatment agent based on 100 parts by weight of the polyamide resin.

The carbon-based reinforcing agent surface-treated with the coupling treatment agent refers to carbon fiber, graphine, CNT, or carbon powder, and when included within the above range, the modulus may be improved to have an NVH effect.

[D] damping ratio (Damping ratio) enhancement additive

In the present invention, the damping ratio improving additive may be used to improve the noise blocking effect by changing the rheological properties of the polyamide resin composition.

That is, since the NVH effect cannot be improved with the inherent rheological characteristics of the polyamide resin composition in the present invention, an additive is used to reinforce the damping ratio.

The damping ratio improving additive is polyphthalamide (PPA), polyester sulfone (PES), polyetheramide (PEI), polyphenylene sulfide (PPS), polyphenyl ether (PPE), polyether ether ketone (PEEK), It may include at least one selected from the group consisting of polyketone and polyimide (PI). The damping ratio improving additive may be selected from those having a glass transition temperature of 100 to 250 °C. Those with a glass transition temperature of less than 100 ° C. are insignificant in NVH improvement, which can be facilitated by processing conditions. When the temperature exceeds 250 ℃, it is not suitable for application due to the problem of cost increase due to high purchase price. The reason for using the damping ratio improving additive can be explained by the following formula expected as follows.

<Equation 2>

The damping ratio evaluated in the material is expressed as tan δ in the above formula, and the larger the loss modulus, the larger the value.

These values are due to the viscoelastic properties of polyamide 6, a polymer material, and the loss modulus is determined by the viscous properties among viscoelastic properties. In other words, it can be said that the method of improving the viscous properties of polyamide 6 improves the damping ratio. Therefore, a damping ratio improving additive was applied to improve the viscous properties of polyamide 6.

When the content of the damping ratio improving additive is 25, the damping ratio (tan δ) becomes small, so the NVH improvement effect is insignificant, and when it exceeds 100 parts by weight, there is a problem in that mechanical strength and flowability are lowered.

manufacturing method

The polyamide resin composition according to the present invention can be prepared by extruding each of the above-described components, that is, polyamide resin, glass fiber, and carbon-based reinforcing agent by applying them to an extruder. Specifically, the polyamide resin composition may be prepared by kneading each component of the polyamide resin composition as described above at 320° C. to 340° C. using a twin-screw extruder. At this time, in order to maximize the kneading of the polyamide resin composition, an extruder having three inlets was used, and polyamide resin and an additive for improving the damping ratio were introduced into the first inlet, glass fibers were introduced into the second inlet, and glass fibers were introduced into the inlet. A carbon-based reinforcing agent may be added. 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 about 150 to 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, a carbon-based reinforcing agent, and a damping ratio improving additive, and the polyamide resin composition has excellent tensile strength, flexural strength, flexural modulus and impact resistance. It has excellent noise blocking properties while maintaining strength.

According to another embodiment of the present invention, a molded article manufactured from the polyamide resin composition described above is provided.

The molded article has a tensile strength of 185 Mpa to 195 Mpa according to the ISO evaluation method ISO 527, a flexural strength of 285 Mpa to 295 Mpa according to ISO 178, and a flexural modulus of 10600 Mpa to 13000 Mpa according to ISO 178, and a damping ratio (tan δ ) has a value of 0.011 to 0.35 and can be applied as an automobile engine room part. In particular, it is suitable as a material for manufacturing cylinder head covers for automobiles, which require mechanical properties such as strength and noise blocking properties at the same time.

Hereinafter, the configuration and effects of the present invention will be described in more detail through specific examples and comparative examples to aid understanding of the present invention. However, the following examples are only for understanding the invention more clearly, and the invention is not limited to the following examples.

Example One

Polyamide 6 resin (Domo's PA6 Domamide 24), glass fiber (NEG's Glass Fiber 262H), carbon-based reinforcing agent (Sunyoung's SYC-TR-PA) and damping ratio improving additive (Evonik's M1000NC) were prepared as shown in Table 1. According to the same composition, a polyamide resin composition was prepared by melt kneading in a twin screw extruder heated to 330°C. The composition was made into chips and dried using a dehumidifying dryer at 100 ° C. for 4 hours, and a specimen containing the polyamide resin composition was prepared using a screw extruder at the same temperature as when melt-kneaded.

Example 2

Specimens containing the polyamide resin composition were prepared in the same manner as in Example 1, except that the carbon-based reinforcing agent was used according to the content shown in Table 1.

Example 3

Specimens containing the polyamide resin composition were prepared in the same manner as in Example 1, except that the damping ratio improving additive was used according to the content shown in Table 1.

Example 4

Specimens containing the polyamide resin composition were prepared in the same manner as in Example 1, except that glass fibers were used according to the contents described in Table 1.

Example 5

Damping ratio improvement additive Specimens containing the polyamide resin composition were prepared in the same manner as in Example 4, except that the content was changed as shown in Table 1.

Example 6

carbon-based reinforcing agent Specimens containing the polyamide resin composition were prepared in the same manner as in Example 1, except that the content was changed as shown in Table 1.

Example 7

Specimens containing the polyamide resin composition were prepared in the same manner as in Example 1, except that the damping ratio improving additive was changed as shown in Table 1.

comparative example 1 to comparative example 3

Specimens containing the polyamide resin composition were prepared in the same manner as in Example 1, except that the glass fiber content was changed as shown in Table 1.

comparative example 4 and comparative example 5

Specimens containing the polyamide resin composition were prepared in the same manner as in Example 1, except that the content of the carbon-based reinforcing agent was changed as shown in Table 1.

comparative example 6

Damping ratio improvement additive Specimens containing the polyamide resin composition were prepared in the same manner as in Example 1, except that the content was changed as shown in Table 1.

comparative example 7

Specimens containing the polyamide resin composition were prepared in the same manner as in Example 1, except that the carbon-based reinforcing agent was changed as shown in Table 1.

polyamide 6 fiberglass carbon-based reinforcing agent Damping ratio improvement additive Example 1 100 70 9 25 Example 2 100 70 11 25 Example 3 100 70 9 45 Example 4 100 80 9 25 Example 5 100 80 9 45 Example 6 100 70 16 25 Example 7 100 70 9 100 Comparative Example 1 100 60 9 25 Comparative Example 2 100 120 9 25 Comparative Example 3 100 70 6 25 Comparative Example 4 100 70 20 25 Comparative Example 5 100 70 9 20 Comparative Example 6 100 70 9 110 Comparative Example 7 100 70 0 25

Property evaluation

For the polyamide resin compositions prepared in Examples and Comparative Examples, tensile strength, flexural strength, impact strength, surface properties, and noise blocking properties were measured in the following manner, and the results are shown in Table 2.

1) Tensile strength: Measured after preparing specimens in accordance with ISO 527

2) Flexural strength: Measured after preparing specimens in accordance with ISO 178.

3) Flexural modulus: Measured after fabricating specimens in accordance with ISO 178.

4) Damping ratio (tan δ) measurement: A specimen of 1 x 6 x 2T was prepared and EXPLEXOR 500 was used.

5) Noise blocking measurement: Evaluation was conducted based on the evaluation method based on ISO 10847:1997(E). On the noise source side, a noise generator and an octave band pass filter. After installing the loudspeaker and power amplifier equipment, build a 3m high soundproof wall at a location of 1.5m, and 500 to 3000Hz noise signal from the noise source at a location 1.5m higher than the height of the soundproof wall at a distance of 3m. The noise was measured while giving Afterwards, the noise reduction interference device was installed at the same height as the soundproof wall height, and the noise was measured at the same separation distance and height, and the noise level difference was calculated using the formula below.

<official>

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

The tensile strength flexural strength flexural modulus Damping ratio (tan δ) Noise level difference (dB) Example 1 211 294 10871 0.145 5.4 Example 2 212 291 12107 0.210 5.7 Example 3 209 293 11089 0.313 6.0 Example 4 214 295 10911 0.234 5.7 Example 5 212 294 10992 0.267 5.9 Example 6 218 297 12990 0.248 5.7 Example 7 210 290 10770 0.334 5.9 Comparative Example 1 178 279 10440 0.139 5.4 Comparative Example 2 220 320 15400 0.128 5.1 Comparative Example 3 212 294 10871 0.06 3.5 Comparative Example 4 212 293 14250 0.288 5.9 Comparative Example 5 214 296 11992 0.08 2.8 Comparative Example 6 202 281 10450 0.138 5.2 Comparative Example 7 210 292 10932 0.04 2.1

As shown in Table 2, it was found that the specimens prepared with the compositions of Examples 1 to 7 had excellent noise blocking properties while maintaining excellent tensile strength, flexural strength, flexural modulus and impact strength. On the other hand, when the content of glass fiber is low or too high (Comparative Examples 1 to 2), the flexural strength and flexural modulus are reduced, and when the content of the carbon-based reinforcing agent is low or too high (Comparative Examples 3 to 4), the damping ratio or flexural modulus is reduced. deterioration was found.

In addition, when the content of the damping ratio improving additive is low or too high (Comparative Examples 5 to 6), it can be seen that the flexural strength tends to decrease or the damping ratio or flexural modulus decreases.

In addition, it was found that the damping ratio was lowered when the carbon-based reinforcing agent was not added (Comparative Example 7).

Claims (8)

70 to 111 parts by weight of glass fiber, 9 to 16 parts by weight of a carbon-based reinforcing agent surface-treated with a coupling treatment agent, and 25 to 16 parts by weight of a damping ratio improving additive, including a polyamide resin, based on 100 parts by weight of the polyamide resin 100 parts by weight,
The carbon-based reinforcing agent surface-treated with the coupling treatment agent is a polyamide resin composition, characterized in that the surface treatment with Poly urethane, Epoxy, PI, or Phenolic resin.
The polyamide resin composition according to claim 1, wherein the polyamide resin has a relative viscosity of 2.0 to 3.5 and a number average molecular weight of 20,000 to 50,000.
The polyamide resin composition according to claim 1, wherein the glass fiber has a chopped shape, has a diameter of 8 to 15 μm, and a length of 2.0 to 5.0 mm, and is treated with a coupling treatment agent.
delete The polyamide resin composition according to claim 1, wherein the damping ratio improving additive has a glass transition temperature of 100 to 250 °C.
The method of claim 1, wherein the damping ratio improving additive is polyphthalamide (PPA), polyester sulfone (PES), polyetheramide (PEI), polyphenylene sulfide (PPS), polyphenyl ether (PPE), polyether ether A polyamide resin composition comprising at least one selected from the group consisting of ketone (PEEK), polyketone, and polyimide (PI).
A molded article manufactured from the polyamide resin composition according to any one of claims 1 to 3 and 5 to 6.
The method of claim 7, wherein the molded article has a tensile strength of 200 Mpa to 220 Mpa according to the ISO evaluation method ISO 527, a flexural strength of 285 Mpa to 300 Mpa according to ISO 178, a flexural modulus according to ISO 178 of 10600 Mpa to 13000 Mpa, and a damping ratio (tan δ ) is a molded article, characterized in that 0.1 to 0.35.