KR20230163170A - Polypropylene resin composition, manufacturing method for same and article comprising same - Google Patents

Abstract

This specification includes polypropylene resin; and a polypropylene resin composition containing glass fibers with an average length of 5 mm to 30 mm, a manufacturing method thereof, and a molded article containing the same.

Description

Polypropylene resin composition, manufacturing method thereof, and molded article containing the same {POLYPROPYLENE RESIN COMPOSITION, MANUFACTURING METHOD FOR SAME AND ARTICLE COMPRISING SAME}

This specification relates to a polypropylene resin composition, a method of manufacturing the same, and a molded article containing the same.

Recently, while the future automobile industry, centered on electric vehicles and self-driving cars, is rapidly emerging as a core industry of the 4th Industrial Revolution, issues such as reducing environmental burden through emission regulations have also emerged. Accordingly, vehicle lightweighting has become the most important topic in the automobile industry, and research is actively underway on the development of plastic composite materials to replace existing steel, especially in the case of vehicle body parts.

Among vehicle body parts, the tailgate is a part that corresponds to the trunk door of vehicles such as wagons or SUVs. The tailgate's panel, excluding glazing, weighs more than 20 kg, making it a part that desperately needs to be lightweight. Currently, mass production of plastic-applied tailgates is underway, mainly in Europe and Japan.

In plastic tailgates, the inner panel contributes the most to rigidity, strength, and dimensional stability. To increase the strength and rigidity of the plastic tailgate inner panel, SMC (Sheet mold compounds) is a composite of unsaturated polyester, a thermosetting resin, and glass fiber, and LFT (Long fiber thermoplastic; hereinafter LFT) is a composite of polypropylene and long fiber glass fiber. etc. have been developed.

However, in the case of LFT granules, they are manufactured through a pultrusion process, where various thermoplastic resins are melted and impregnated between thousands of strands of reinforcing fibers. The quality of the product depends on the degree of impregnation, so not only is the technical difficulty high, but the equipment required for manufacturing is expensive.

The mechanical properties of plastic composite materials are proportional to the length of the fiber, and it is generally known that over 95% of the properties can be expressed at 1.0 mm or more. In the case of LFT (Long fiber thermoplastic), it has a fiber length of 6.0 mm or more, which is advantageous for high-rigidity plastic parts. However, LFT can also have a shorter fiber length depending on injection conditions and mold structure, and is also used in SFT (Short fiber thermoplastic). Compared to this, it has the disadvantage of being less fair, such as an increase in the melting temperature of the resin and mold gate size, a decrease in back pressure and injection speed, and an increase in the unit price of the parts associated with it.

Therefore, there is a need to develop technology that optimizes both physical properties and process performance.

Japanese Patent Publication No. 2009-298139

This specification relates to a polypropylene resin composition, a method of manufacturing the same, and a molded article containing the same.

One embodiment of the present invention is a polypropylene resin; and a polypropylene resin composition containing glass fibers having an average length of 5 mm to 30 mm.

Another embodiment of the present invention is polypropylene resin; and mixing glass fibers with an average length of 5 mm to 30 mm.

Another embodiment of the present invention provides a molded article containing the polypropylene resin composition described above.

When extruding using the polypropylene resin composition according to an exemplary embodiment of the present invention, the destruction of glass fibers is small and the length of glass fibers in the molded product is long. Therefore, the physical properties, especially rigidity, of the molded product extruded from the polypropylene resin composition of the present invention are excellent.

Figure 1 is a photograph of the pellet of Example 2 according to an embodiment of the present invention.

Hereinafter, this specification will be described in more detail.

One embodiment of the present invention is a polypropylene resin; and a polypropylene resin composition containing glass fibers having an average length of 5 mm to 30 mm.

The present invention provides optimal screw technology in the compounding technology of the existing SFT (Short Fiber Thermoplastic) manufacturing process; And by applying middle glass fiber, process performance can also be improved while increasing physical properties.

The present invention applies middle glass fiber to increase strength by increasing the length of the remaining glass fiber while minimizing glass fiber destruction in the extruder. Additionally, during the extrusion process, the number of cutter blades and rotary knives is minimized to increase the pellet length from the conventional 3 mm to 4 mm size to 12 mm. Therefore, rigidity can be secured by maximizing the length of the glass fiber on the molded product after injection molding. The GF (Glass Fiber) composite resin of the present invention can be used in S plastic tailgates.

Additionally, the present inventors discovered an optimal screw configuration that can minimize the destruction of middle glass fibers and improve dispersibility in compounding equipment used in the SFT manufacturing process.

In one embodiment of the present invention, the polypropylene resin composition includes glass fibers, thereby maintaining the lightweight properties of the polypropylene resin and greatly improving the mechanical strength. Specifically, the glass fiber can be complexed with polypropylene resin, greatly improving the mechanical strength of the resin.

In one embodiment of the present invention, the average particle diameter of the glass fiber may be 0.01 mm to 1 mm, 0.01 mm to 0.015 m, 0.01 mm to 0.012 mm, or 0.01 mm to 0.011 mm. The method of measuring the average particle diameter of the glass fiber is to cut a cross section of the specimen at -30°C and measure the particle diameter of the glass fiber within the specimen using SEM. Within the above numerical range, the flowability of the polypropylene resin composition containing glass fiber is not disturbed and the mechanical strength can be effectively improved.

In one embodiment of the present invention, the average length of the glass fiber may be 5 mm to 30 mm. Specifically, it may be 5mm to 20mm, 5mm to 16mm, 6mm to 12mm, 7mm to 10mm, or 8mm to 9mm. Within the above numerical range, mechanical strength can be improved by increasing the number of remaining glass fibers.

In one embodiment of the present invention, the content of the glass fiber is 15 parts by weight to 50 parts by weight, or 30 parts by weight to 50 parts by weight, based on 100 parts by weight of the total weight of the polypropylene resin composition. Within the above numerical range, the flowability of the polypropylene resin composition containing glass fiber is not disturbed and the mechanical strength can be effectively improved.

In one embodiment of the present invention, the glass fiber may be E glass fiber, C glass fiber, A glass fiber, H glass fiber, G glass fiber, or S glass fiber. Additionally, two or more of the above types of glass fibers may be used in combination.

In one embodiment of the present invention, the glass fiber may be S glass fiber.

In one embodiment of the present invention, the polypropylene (PP) is a homopolymer, copolymer, random copolymer, or block copolymer, regardless of the type, and is used in the industry. You can use what you normally use.

In one embodiment of the present invention, the melting index (MI) of the propylene is 5 g/10 min to 60 g/10 min, and 10 g/10 min to 40 g/min. The melt index (MI) is defined as the weight of PP passing through an orifice with a diameter of 2.095 mm for 10 minutes at a load of 2160 g and a temperature of 230 ° C. according to ASTM D1238.

In one embodiment of the present invention, the polypropylene resin composition includes one or more of a compatibilizer, antioxidant, lubricant, dye, pigment, and rubber.

In one embodiment of the present invention, the polypropylene resin composition includes a compatibilizer, an antioxidant, a lubricant, and a pigment.

In one embodiment of the present invention, based on 100 parts by weight of the total weight of the polypropylene resin composition,

The content of polypropylene resin is 30 parts by weight to 85 parts by weight,

The content of glass fiber is 15 to 50 parts by weight,

The content of the compatibilizer is 2 to 8 parts by weight,

The content of antioxidant is 0.01 to 0.3 parts by weight,

The content of the lubricant is 0.01 to 0.03 parts by weight,

The content of the pigment is 0.1 to 3 parts by weight.

In one embodiment of the present invention, the polypropylene resin composition can improve wettability and impregnation of the composition and improve mechanical strength by including a compatibilizer. Specifically, by allowing the glass fiber to be well composited with the polypropylene resin, the intended purpose of the present invention can be achieved.

In one embodiment of the present invention, the reactive compatibilizer is 2-(3,4 epoxycyclohexyl) ethyltrimethoxysilane [2-(3,4 epoxycyclohexyl)ethyltrimethoxysilane, 3-glycythoxypropyl methyldimethoxy Silane [3-glycidoxypropyl methyldimethoxysilane], 3-glycidoxypropyl trimethoxysilane [3-glycidoxypropyl trimethoxysilane], 3-glycidoxypropyl triethoxysilane [3-glycidoxypropyl triethoxysilane], [N-2-(aminoethyl )-3-Aminopropylmethyldimethoxysilane N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane], N-2-(aminoethyl)-3-aminopropyltrimethoxysilane [N-2-(aminoethyl)-3 -aminopropyltrimethoxysilane], 3-aminopropyltrimethoxysilane [3-aminopropyltrimethoxysilane], 3-aminopropyltriethoxysilane [3-aminopropyltriethoxysilane], 3-triethoxysilyl-N-(1,3 dimethyl-butylidene ) Propylamine [3-triethoxysilyl-N-(1,3 dimethyl-butylidene)propylamine], N-phenyl-3-aminopropyltrimethoxysilane [N-phenyl-3-aminopropyltrimethoxysilane], N-(vinylbenzyl)- 2-aminoethyl)-3-aminopropyltrimethoxysilane hydrochloride [N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride], N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltri It may include one or more selected from the group consisting of methoxysilane hydrochloride [N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride] and combinations thereof.

In one embodiment of the present invention, the pigment may be carbon black masterbatch.

In one embodiment of the present invention, the flow index measured at a temperature of 70°C and a load of 21.6 kg may be 1 g/10 min or more. Specifically, it may be 1 g/10 min to 50 g/10 min, 1 g/10 min to 10 g/10 min, 1 g/10 min to 5 g/10 min, or 1 g/10 min to 3 g/10 min. Within the above numerical range, excellent fluidity of the composition is maintained, and a molded article with excellent appearance and excellent strength can be obtained.

Another embodiment of the present invention is polypropylene resin; and mixing glass fibers with an average length of 5 mm to 30 mm.

In one embodiment of the present invention, the glass fibers may be supplied in the form of glass fiber bundles. The number of bundles of the glass fibers may be 900 to 1,500, more preferably 900 to 1,100. Within the above numerical range, the dispersibility and fairness of glass fiber can be improved.

In one embodiment of the present invention, the polypropylene resin; And the glass fiber can be supplied using an electric feeder or popper.

In one embodiment of the present invention, a kneading step of kneading the mixture; And it may include an extrusion step of extruding the mixture.

In one embodiment of the present invention, the kneading step; Alternatively, the extrusion step may use a melt-kneading extruder and may include two or more raw material supply ports. At this time, the polypropylene resin; and glass fiber may be supplied from the same or different supply ports.

In one embodiment of the present invention, the kneading step may be performed at a temperature of 180°C or higher and a speed of 200 rpm or higher. The temperature may be 180°C to 200°C, and the speed may be 200rpm to 300rpm or 200rpm to 250rpm. The temperature refers to the temperature inside the extruder where the kneading step is performed, and the speed refers to the number of revolutions per minute (rpm) of the extruder screw. In the above temperature range, the melting point (Tm) of the ultra-high molecular weight polypropylene resin is maintained at a temperature of about 170° C. or higher for a sufficient residence time in the extruder, so that the polypropylene resin can be sufficiently melted.

In one embodiment of the present invention, the extrusion step uses blades having 5 to 50 knives, 5 to 15 knives, or 5 to 10 knives. By reducing the number of rotary knives, the length of the pellet can be increased. Specifically, pellets with an average length of 3 mm to 20 mm, pellets of 8 mm to 20 mm, or pellets of 8 mm to 15 mm can be produced. Adjust the pellet to 12mm to increase the number of glass fibers that affect the physical properties of the molded product.

Another embodiment of the present invention provides a molded article containing the polypropylene resin composition described above. The application field of the molded product is automotive parts. Specifically, the molded product is used in automobile tailgates.

In one embodiment of the present invention, the tensile strength of the molded product measured according to ASTM D638 may be 800 kg/cm ² or more.

In one embodiment of the present invention, the impact strength of the molded product measured according to the ASTM D256 standard may be 7 kg*?*cm/cm or more.

Hereinafter, the present invention will be described through examples. However, the scope of the present invention is not limited to the scope of the following examples, and are introduced to explain the present invention in more detail.

Comparative Example 1 and Example 1: Glass Fiber Length

A polypropylene resin composition was prepared and extruded by putting it into a twin-screw extruder at the weight ratio shown in Table 1 below and performing a series of melting and kneading processes. The operating conditions at this time are as shown in Table 2 below. The extruder used SM platec equipment, the extruder meter used a twin screw extruder of 42mm and L/D 36, and the glass fiber feeder used a K-TRON BELT FEEDER. used. At this time, the length of the pellets produced in Comparative Example 1 and Example 1 was 4 mm.

Classification (weight ratio) Comparative Example 1 Example 1 polypropylene LOTTE J170
(MI: 30 g/10 min) 54.4 54.4 glass fiber NEG T-480
(4mm) 40 TAISAN HM5387
(9mm) 40 compatibilizer SK SOLUMER 8613L 4 4 antioxidant Songwon Industry S-1010 0.1 0.1 Songwon Industry S1680 0.1 0.1 active Shinwon Chemical Ca-st 0.1 0.1 BLACK M/B MK450H 1.3 1.3

Screw Capacity Knife Processing temperature (℃) degree of vacuum rpm kg number of days C-1 C-2 C-3 C-4 C-5 C-6 C-7 C-8 adapter DIE mmHg 320 60 32 180 210 210 210 210 210 210 210 210 220 680

Example 2: Comparison of physical properties according to the number of cutter knives (pellet length)

A polypropylene resin composition was prepared and extruded in the same manner as in Example 1, but the number of knife blades was changed to 8. At this time, the pellets prepared in Example 2 are shown in Figure 1. The length of the pellet is 9mm.

<Experiment method>

The physical properties of each molded product were tested according to the measurement method below.

1) Tensile strength (kg/cm ² ): ASTM D638 (measures the maximum strength until the specimen breaks)

2) Elongation (%): ASTM D638 (Measuring ductility properties until specimen fracture)

3) Flexural strength (kg/cm ² ): ASTM D790 (measurement of maximum strength generated from specimen)

4) Flexural modulus (kg/cm ² ): ASTM D790 (Measuring the ratio of the stress applied to the specimen to the strain created by the applied stress in the area where the strain is linearly proportional to the stress)

5) Impact strength (kg*cm/cm): ASTM D256 (Notched)

<Experimental Example 1>

A comparison of physical properties according to the length of glass fiber is shown in Table 3 below.

Properties unit Comparative Example 1 Example 1 tensile strength kg/ ^cm2 832 828 elongation % 3.7 3.7 Flexural strength kg/ ^cm2 1,123 1,185 Flexural modulus of elasticity kg/ ^cm2 58,563 59,163 impact strength kg*cm/cm 6.8 7.1

<Experimental Example 2>

A comparison of physical properties according to the number of cutter knives (pellet length) is shown in Table 4 below.

Properties unit Example 1 Example 2 tensile strength kg/ ^cm2 842 861 elongation % 3.9 4.0 Flexural strength kg/ ^cm2 1,142 1,178 Flexural modulus of elasticity kg/ ^cm2 58,902 60,123 impact strength kg*cm/cm 6.7 7.3

From Table 3, it can be seen that Example 1 of the present invention has increased flexural strength, flexural modulus, and impact strength. From Table 4, it can be seen that the physical properties of the pellets of Example 2 with a small number of blade knives are improved.

Claims (14)

polypropylene resin; and
A polypropylene resin composition comprising glass fibers having an average length of 5 mm to 30 mm. In claim 1,
A polypropylene resin composition wherein the average length of the glass fibers is 6mm to 12mm. In claim 1,
A polypropylene resin composition in which the content of the glass fiber is 15 parts by weight to 50 parts by weight based on 100 parts by weight of the total weight of the polypropylene resin composition. In claim 1,
A polypropylene resin composition wherein the glass fiber is S glass fiber. In claim 1,
The polypropylene resin composition includes one or more of a compatibilizer, antioxidant, lubricant, dye, pigment, and rubber. In claim 5,
The compatibilizer is 2-(3,4 epoxycyclohexyl) ethyltrimethoxysilane [2-(3,4 epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyl methyldimethoxysilane [3-glycidoxypropyl methyldimethoxysilane], 3- Glycidoxypropyl trimethoxysilane [3-glycidoxypropyl trimethoxysilane], 3-glycidoxypropyl triethoxysilane [3-glycidoxypropyl triethoxysilane], [N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane], N-2-(aminoethyl)-3-aminopropyltrimethoxysilane [N-2-(aminoethyl)-3-aminopropyltrimethoxysilane], 3-aminopropyltrime Toxysilane [3-aminopropyltrimethoxysilane], 3-aminopropyltriethoxysilane [3-aminopropyltriethoxysilane], 3-triethoxysilyl-N-(1,3 dimethyl-butylidene)propylamine [3-triethoxysilyl-N- (1,3 dimethyl-butylidene)propylamine], N-phenyl-3-aminopropyltrimethoxysilane [N-phenyl-3-aminopropyltrimethoxysilane], N-(vinylbenzyl)-2-aminoethyl)-3-aminopropyl Trimethoxysilane hydrochloride [N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride], N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride [N-(vinylbenzyl) )-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride] and combinations thereof. polypropylene resin; and mixing glass fibers having an average length of 5 mm to 30 mm. In claim 7,
A kneading step of kneading the mixture; and
A method for producing a polypropylene resin composition comprising an extrusion step of extruding the mixture. In claim 8,
The extrusion step is a method of producing a polypropylene resin composition using blades with 5 to 50 knives. In claim 8,
The extrusion step is a method of producing a polypropylene resin composition to produce pellets with an average length of 3 mm to 20 mm. A molded article comprising the polypropylene resin composition according to any one of claims 1 to 6. In claim 11,
A molded article having a tensile strength of 800 kg/cm ² or more as measured according to ASTM D638. In claim 11,
A molded product with an impact strength of 7 kg*cm/cm or more measured according to ASTM D256 standard. In claim 11,
The molded product is a molded product used in an automobile tailgate.