KR102690844B1 - Recycled polyamide resin composition, molded article comprising same and manufacturing method for same - Google Patents

Abstract

One embodiment of the present invention is a recycled polyamide resin; glass flakes; and a recycled polyamide resin composition containing cellulose fibers.

Description

Recycled polyamide resin composition, molded article containing the same, and method for manufacturing the same {RECYCLED POLYAMIDE RESIN COMPOSITION, MOLDED ARTICLE COMPRISING SAME AND MANUFACTURING METHOD FOR SAME}

This specification relates to a recycled polyamide resin composition, a molded article containing the same, and a method for manufacturing the same.

In general, polyamide resin has excellent mechanical strength, heat resistance, chemical resistance, abrasion resistance, electrical insulation, and arc resistance, and is used in all industrial fields such as automobile interior and exterior, engine parts, electrical and electronic components, sporting goods, and industrial materials. It is used for a wide range of purposes, and has been especially applied to parts that require durability due to its excellent mechanical strength. However, despite these advantages and the possibility of many uses, polyamide resin has weak impact strength and high molding shrinkage due to its characteristics as a crystalline resin. On the other hand, it has high moisture absorption rate and ultraviolet ray resistance due to the hydrophilic amide functional group. There is a disadvantage that the surface is easily oxidized when exposed to etc.

Accordingly, polyamide resins, as disclosed in U.S. Patent No. 5,851,238, U.S. Patent No. 5,814,107, European Patent No. 1312 647, Republic of Korea Patent No. 1,013,858, Republic of Korea Patent No. 921052, and Japanese Patent Publication No. 63-0305148, etc. Technologies are being developed to complement insufficient physical properties and improve functionality by mixing (alloying) with another resin or by additionally adding reinforcing agents such as glass fiber, inorganic materials, and carbon fiber to polyamide resin or various additives. Polyamide resin with enhanced physical properties is being applied to a variety of high-performance core parts of automobiles. In particular, parts materials are gradually being replaced with lightweight plastics to improve fuel efficiency and reduce carbon dioxide (CO2) emissions in automobiles. In recent trends, the scope of application is expanding more rapidly.

Specific examples of automotive parts using reinforced polyamide materials include cylinder head covers, air intake manifolds, outside door handles, and radiators that require aluminum or higher physical properties. There are head tanks (radiator head tanks), front end modules, etc. Among these, the front end module is a part that acts as a carrier on which components of the front part of the car, such as intercooler, horn, cooling fan, and headlamp, can be installed in batches. The module (module) is designed to facilitate assembly for the purpose of reducing assembly time and cost. It is one of the moduleized parts.

Front-end modules are generally divided into a plastic type made only of plastic and a hybrid type made by inserting a steel plate and injection molding. The plastic type is light in weight and easy to injection mold, but lacks rigidity and durability, and is used as a heavy product. While there is a problem of deformation when attached, the hybrid type has excellent rigidity and durability, but has the problem that the product weight increases due to the weight of the steel plate and forming is not easy. For this reason, by applying reinforced polyamide material to the front end module, the product's lightness, formability, and durability are simultaneously improved.

Meanwhile, the automobile industry has recently put a lot of effort into improving not only excellent performance but also the aesthetics of the interior and exterior design of automobiles, and in accordance with this trend, a variety of cover products for various automobile parts are being developed. A representative example of such component covers is the engine cover. The automobile engine cover that covers the top of the engine creates a clean appearance of the engine room, protects the engine from contamination, and even blocks engine noise. Due to these advantages, the scope of application, which was previously mainly applied only to expensive large vehicles, is gradually expanding to all vehicle types.

Due to the nature of these engine cover materials being installed around the engine, they must basically have excellent mechanical properties and heat resistance, as well as good dimensional stability. Ultimately, since they are the first thing to be seen with the naked eye when the engine room is opened, when molded into a cover shape, the surface There are strict requirements for clean manufacturing. Currently, cover products that satisfy various required physical properties depending on the characteristics of each component, such as engine cover materials, are being produced. Nevertheless, considering the recent strengthening of end-of-life vehicle recycling laws at home and abroad, the development of technology to actively recycle plastic resources generated from end-of-life vehicles as a raw material for covering materials for these auto parts is still lacking. This is the situation.

U.S. Published Patent No. 5,851,238

This specification relates to a recycled polyamide resin composition that recycles waste plastic resources and has excellent mechanical properties, a molded article containing the same, and a method for manufacturing the same.

One embodiment of the present invention is a recycled polyamide resin; and a recycled polyamide resin composition comprising glass fibers.

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

Another embodiment of the present invention is a recycled polyamide resin; and mixing glass fibers to provide a method for producing the above-described recycled polyamide resin composition.

Molded articles manufactured using the recycled polyamide resin composition according to an exemplary embodiment of the present invention have excellent mechanical properties, heat resistance, and dimensional stability.

Figures 1 and 2 show the shape and electron micrograph of glass flakes.
Figure 3 shows the shape of cellulose fibers.
Figure 4 shows the appearance of the phosphorus-based antioxidant.
Figure 5 shows the shape of the screw used in the present invention.
Figure 6 shows the inner and outer diameters of the screw.
Figure 7 shows the form of a twin screw extruder.

Hereinafter, this specification will be described in detail.

In this specification, recycled polyamide resin refers to polyamide resin recovered from end-of-life automobiles, and is distinguished from newly synthesized new polyamide resin.

One embodiment of the present invention is a recycled polyamide resin; and a recycled polyamide resin composition comprising glass fibers.

Conventional recycled polyamide resin has weaker physical properties compared to new polyamide resin, so it has the disadvantage of being difficult to apply for applications requiring mechanical properties or heat resistance. In particular, it was difficult to apply to vehicle engines, which require all mechanical properties, heat resistance, and dimensional stability. Accordingly, the present inventors attempted to solve the above problem by developing a recycled polyamide resin composition with excellent physical properties by including glass fiber in the recycled polyamide resin.

In one embodiment of the present invention, the recycled polyamide resin composition includes glass fiber. The glass fiber is a material made by pulling glass as thin as a fiber and may be referred to as glass fiber. It has excellent insulation properties and is easy to process.

In one embodiment of the present invention, the recycled polyamide resin composition includes cellulose fibers.

In one embodiment of the present invention, the recycled polyamide resin composition includes glass flakes. The shape and electron micrograph of the glass flake are shown in Figures 1 and 2.

The glass flakes are thin, transparent, irregularly shaped, plate-shaped pieces of glass with a wide particle size distribution and high aspect ratio (ratio of average particle diameter to particle thickness). The particle size of glass flakes is generally 10~2000um or 10~4000um, and the average particle size (D50) is in the range of 20~300um, 30~300um, or 15~600um.

The glass flakes can be produced by breaking glass bubbles or by crushing the liquid glass melt in a centrifuge and then crushing the ribbon-shaped glass pieces.

The glass flakes can be effective by controlling the particle size distribution, average particle diameter, and thickness of the glass particles. Additionally, glass flakes can be made from several different glasses, such as E-glass, S-glass, ECR-glass, and C-glass. A typical representative example of glass flake has the following particle size distribution: Microglas REF-160 A from NGF Europe: 10% of the glass particles are in the range of 300 to 1700 μm in diameter, 65% are in the range of 45 to 300 μm in diameter, and 25% are particles. It is less than 45μm in diameter. Here, the thickness is 5μm. The type of glass used is E-glass. Glass flakes can be surface coated in various sizes using, for example, amine silane or epoxy silane to improve adhesion to polymer matrix.

In one embodiment of the present invention, the average particle size of the glass flakes may be 10 to 100um, 10 to 60um, or 18 to 40um. Within the above numerical range, the bonding strength can be improved due to excellent compatibility with other resin components in the recycled polyamide resin composition.

In one embodiment of the present invention, the thickness of the glass flake may be 0.1 um to 5 um.

In one embodiment of the present invention, the glass flakes may be E-, S-, C-, or ECR-glass. Specifically, glass flakes of E-glass are particularly preferred. The average particle size of the glass flakes can be measured using laser diffraction particle size analysis. The glass flakes used may be coated with aminesilanes, vinyl silanes, epoxy silanes or acrylosilanes, with surface coating with aminesilanes being particularly preferred.

In one embodiment of the present invention, the content of the glass flakes may be 5 to 30 parts by weight based on 100 parts by weight of the regenerated polyamide resin. Within the above numerical range, compatibility with other resin components in the regenerated polyamide resin composition may be excellent, so that the bonding strength may be improved.

In one embodiment of the present invention, the content of the glass fiber may be 10 to 100 parts by weight based on 100 parts by weight of the recycled polyamide resin. Meanwhile, the content of the glass fiber may be 15 to 90 parts by weight or 20 to 80 parts by weight based on 100 parts by weight of the recycled polyamide resin. Within the above numerical range, the bonding strength can be improved due to excellent compatibility with other resin components in the recycled polyamide resin composition.

In one embodiment of the present invention, the recycled polyamide resin composition includes cellulose fibers. Accordingly, tensile strength and impact strength can be improved. Specifically, tensile strength or impact strength can be improved by more than 10%, preferably by more than 20%. In addition, it can exhibit excellent ductility even at low temperatures and has the effect of reducing wear on machines and tools during injection molding.

In one embodiment of the present invention, the cellulose fiber is used as a filler. Conventional fillers are roughly divided into two types: extenders, which are added in large quantities to reduce costs, and reinforcing fillers, which are added to improve mechanical, thermal, and electrical properties or processability. Fillers are generally mixed in large quantities compared to other additives, and in many cases, 40 to 50% are used. When fillers are mixed with polymers, their effectiveness varies significantly depending on their chemical composition or shape. Therefore, types of fillers are classified into inorganic and organic depending on their chemical composition, and depending on their shape, they are powdered, flat, needle-shaped, spherical, fiber, or fiber. It is classified into fabrics, etc.

Among these various fillers, the fillers used in PA6 and 66 include glass fiber, calcium carbonate, talc, mica, silica, wood flour, chalk, and woolas-tonite. The main purpose of fillers is to improve physical properties and processability. Since a large amount of fillers are mixed, defects such as deterioration of physical properties may appear in some cases. In particular, the talc used by our company has been the subject of much controversy due to the asbestos issue.

In one embodiment of the present invention, the cellulose fiber may be a cellulose fiber in the form of chop fiber. In this case, the balance between rigidity and stability/resistance is excellent, and it is possible to provide a lightweight structure and a high level of crash resistance. In addition, since the fiber exhibits a high level of elastic modulus (19.5 GPa) and sufficient elongation (10%), it can have a significant energy absorption capacity. Figure 3 shows the cellulose fiber in the chop fiber form.

In one embodiment of the present invention, the content of the cellulose fiber may be 5 to 30 parts by weight based on 100 parts by weight of the recycled polyamide resin. Within the above numerical range, the tensile strength and impact strength of the recycled polyamide resin composition can be further improved.

The recycled polyamide resin composition according to an exemplary embodiment of the present invention includes a phosphorus-based antioxidant. By including the phosphorus-based antioxidant, the heat resistance of the recycled polyamide resin composition can be improved. In the recycled polyamide resin composition, discoloration occurs due to discoloration substances as the processing temperature increases, and the phosphorus-based antioxidant has the effect of increasing the temperature at which the discoloration phenomenon occurs (heat resistance temperature). Figure 4 shows the form of the phosphorus-based antioxidant.

In particular, when used together with a conventional phenol-based antioxidant, phosphites contained in the phosphorus-based antioxidant can prevent the formation of a quinoidal structure, which is a discoloring component of the phenol-based antioxidant, thereby preventing discoloration.

In one embodiment of the present invention, the phosphorus-based antioxidant is trimethyl phosphate, triethyl phosphate, triphenyl phosphate, triethyl phosphono acetate, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol. -Di-phosphite (Bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol-di-phosphite) and bis(2,4-di-tert-butylphenyl)pentaerythritol-di-phosphite It may be one or more types selected from the group consisting of (Bis(2,4-di-tert-butylphenyl)pentraerythritol-di-phosphite).

In one embodiment of the present invention, the content of the phosphorus-based antioxidant may be 0.1 part by weight to 5 parts by weight, 0.1 part by weight to 3 parts by weight, or 0.1 part by weight to 1 part by weight based on 100 parts by weight of the recycled polyamide resin. . Within the above numerical range, the discoloration prevention function can be further improved.

In one embodiment of the present invention, the recycled polyamide resin composition may further include a phenol-based antioxidant.

In one embodiment of the present invention, the recycled polyamide resin composition includes a UV stabilizer, a halogenated or non-halogenated flame retardant additive, a heat stabilizer, a light stabilizer, a polymerization regulator, a plasticizer, a lubricant, a rheology modifier, a friction modifier, an anti-blocking agent, and an electrification agent. It may further include one or more additives selected from the group consisting of inhibitors, antioxidants, UV absorbers, pigments, and dyes.

In one embodiment of the present invention, the recycled polyamide resin composition may further include a new polyamide resin.

In one embodiment of the present invention, the new polyamide resin is polyamide 6, polyamide 12, polyamide 66, polyamide 6/66, polyamide 6/12, polyamide 6/6T, polyamide 6/6I. and it may be one or more selected from the group consisting of copolymers thereof.

In one embodiment of the present invention, the new polyamide resin may preferably have a relative viscosity of 2.2 to 3.3 and a number average molecular weight of 20,000 to 50,000. If the relative viscosity is less than 2.2, excellent effects cannot be obtained in terms of improving rigidity and dimensional stability, and if it exceeds 3.3, surface defects and non-moulding phenomena may occur due to a decrease in fluidity. In addition, if the number average molecular weight is less than 20,000, there is a problem that the rigidity is reduced, and if it is more than 50,000, the flowability is poor due to the high viscosity, so melt kneading may not be performed smoothly. At this time, relative viscosity (RV) is a value measured by measuring the viscosity of a solution containing 1 g of polyamide resin in 100 ml of 96% sulfuric acid at 20°C, and number average molecular weight (Mn) is measured by GPC (Gel Permeation Chromatography). ), and the polyamide resin used may be made in the form of chips and sufficiently dried in a dehumidifying dryer.

In one embodiment of the present invention, the recycled polyamide resin composition includes a polyolefin resin containing a polar group. In this case, impact resistance or moisture stability may be improved.

In one embodiment of the present invention, the polar group of the polyolefin resin containing the polar group may be a carboxy group, and in this case, excellent moisture stability is achieved without deterioration of other physical properties.

In one embodiment of the present invention, the polyolefin resin containing the polar group may be an ethylene-α-olefin copolymer modified with at least one compound of α,β-unsaturated dicarboxylic acid and anhydride thereof, In this case, it has the effect of greatly improving moisture stability, and the composition to which this is applied has excellent dimensional stability, which is the ability to maintain its original size even under various environmental conditions. At this time, the above-mentioned modification is not particularly limited in the case of modification by a polymer modification method commonly used in the technical field to which the present invention pertains, and for example, α,β-unsaturated dicarboxylic acid and its It may mean grafting by adding at least one compound among anhydrides. In another example, when preparing an undenatured copolymer, at least one compound among α,β-unsaturated dicarboxylic acid and its anhydride is used as a comonomer. This may mean copolymerization by adding . Examples of the α,β-unsaturated dicarboxylic acid and its anhydride include maleic acid, fumaric acid, citric acid, and their anhydride, and preferably maleic anhydride. In this case, moisture stability is greatly improved.

In one embodiment of the present invention, the α-olefin included in the polyolefin resin containing the polar group is, for example, α-olefin with 3 to 10 carbon atoms, α-olefin with 5 to 10 carbon atoms, preferably 1-octenyl. This has the effect of greatly improving moisture stability within this range.

In one embodiment of the present invention, the number average molecular weight of the polyolefin resin containing the polar group may be 50,000 to 400,000 g/mol, preferably 100,000 to 300,000 g/mol, and both physical properties and processability within this range. It has excellent effects. The number average molecular weight can be measured by GPC analysis using PS (Polystyrene) as a standard material.

In one embodiment of the present invention, the content of the polyolefin resin containing the polar group is 0.1 to 10 parts by weight, 0.1 to 7 parts by weight, and 1 to 5 parts by weight based on 100 parts by weight of the recycled polyamide resin. It could be wealth. Moisture stability or impact resistance can be improved within the above numerical range.

One embodiment of the present invention provides a molded article containing the above-described recycled polyamide resin composition. The molded product can be used for automobile interior and exterior materials or automobile engine parts. In particular, mechanical properties and heat resistance are improved, making it suitable for use in automobile engine parts exposed to high temperature environments.

One embodiment of the present invention is a recycled polyamide resin; and mixing glass fibers to provide a method for producing the above-described recycled polyamide resin composition.

In one embodiment of the present invention, the method for producing the recycled polyamide resin composition may include melt-extruding the mixture.

In one embodiment of the present invention, the melt-extruding step may be performed in an extruder equipped with two or more divided areas. For example, the extruder may include three zones, where conveying and melting of the solid raw material is performed in the first zone. In the second area, mixing and liquefaction by screw are performed, and in the third area, extrusion and discharge are performed.

In one embodiment of the present invention, the step of melt-extruding the mixture may use a twin-screw extruder having a ratio (Do/Di) of the inner diameter (Di) and outer diameter (Do) of the screw of 1 to 2. At this time, the free volume of the process increases, and heat generation can be controlled by reducing the friction surface inside the screw and sleeve inside the extruder. Specifically, it can be seen that shear heating decreases when the screw temperature drops by 5°C under the same compression conditions. Figure 5 shows the shape of the screw with an increased free volume.

In one embodiment of the present invention, in the step of melt-extruding the mixture, the ratio (Do/Di) of the inner diameter (Di) and outer diameter (Do) of the screw may be 1 to 2, 1.5 to 1.7, or 1.6 to 1.8. . Within the above range, heat resistance performance can be improved and damage to glass flakes contained within the composition can be prevented. Figure 6 shows the inner and outer diameters of the screw.

In one embodiment of the present invention, the step of melt-extruding the mixture may use a co-rotating intermeshing twin-screw extruder (TSE). Figure 7 shows the shape of the twin screw extruder.

Hereinafter, the present invention will be described in more detail through examples. However, the scope of the present invention is not limited to the examples below.

<Experimental Example 1>

Example 1

Prepare ground recycled polyamide resin (PA66) by drying it to a moisture content of 5 wt% and mixing it with pigments and additives (heat stabilizer, etc.) in a ribbon mixer. The prepared raw materials are put into a twin screw extruder (70mm, L/D: 44), and glass fiber and cellulose chop fiber (diameter: 4mm) are put into the side feeder and extruded to produce a recycled polyamide resin composition. Manufactured. Detailed process conditions are shown in Table 1.

Examples 2 to 5

A recycled polyamide resin composition was prepared in the same manner as in Example 1, except that the composition ratio was changed as shown in Table 1 below.

The physical properties of the recycled polyamide resin compositions prepared in Examples 1 to 5 were measured in the following manner and are shown in Table 1 below.

How to measure physical properties

1. Tensile strength: ASTM D638

2. Izod impact strength: ASTM D256

3. Specific gravity: ASTM D792

division Composition (wt%) Physical property measurements PA66 glass fiber cellulose chop
fiber(4mm) tensile strength
(kgf/ ^cm2 ) IZOD impact strength
(kgfcm/cm) importance Example 1 65 28 7 1,230 7.5 1.37 Example 2 65 25 10 1,290 7.7 1.36 Example 3 70 23 7 1,360 7.3 1.33 Example 4 70 20 10 1,390 7.5 1.32 Example 5 65 35 0 1,210 7.1 1.41

<Experimental Example 2>

Examples 6 to 9

After drying the crushed recycled PA6 to a moisture content of 5 wt%, prepare it by mixing pigments and additives (heat stabilizer, etc.) in a ribbon mixer. The prepared raw materials were put into a twin screw extruder (70mm, L/D44), and glass fiber and glass flake were put into the side feeder and extruded to produce a recycled polyamide resin composition. Detailed process conditions are shown in Table 2. The physical properties of the manufactured recycled polyamide resin composition were measured in the following manner and are shown in Table 2 below.

division Composition (wt%) Physical property measurements PA6 glass fiber glass flakes tensile strength
(kgf/ ^cm2 ) IZOD impact strength
(kgfcm/cm) Example 6 60 40 0 910 7.5 Example 7 60 30 10 860 8.0 Example 8 60 25 15 800 8.5 Example 9 60 20 20 740 9.1

From the above results, it was confirmed that when the recycled polyamide resin composition contained glass fibers, physical properties such as tensile strength were improved. Meanwhile, it was confirmed that physical properties were further improved when cellulose fibers were further included in addition to glass fibers. there was.

Claims (14)

Recycled polyamide resin;
glass fiber;
glass flakes; and
Contains cellulose fibers,
The content of the glass fiber is 20 to 80 parts by weight based on 100 parts by weight of the recycled polyamide resin,
The thickness of the glass flake is 0.1um to 5um,
The content of the glass flakes is 5 to 30 parts by weight based on 100 parts by weight of the recycled polyamide resin,
A recycled polyamide resin composition in which the content of the cellulose fibers is 5 to 30 parts by weight based on 100 parts by weight of the recycled polyamide resin. delete delete delete delete delete delete In claim 1,
Selected from the group consisting of UV stabilizers, halogenated or non-halogenated flame retardant additives, heat stabilizers, light stabilizers, polymerization modifiers, plasticizers, lubricants, rheology modifiers, friction modifiers, antiblocking agents, antistatic agents, antioxidants, UV absorbers, pigments, dyes. A recycled polyamide resin composition further comprising one or more additives. In claim 1,
A recycled polyamide resin composition further comprising a new polyamide resin. A molded article comprising the recycled polyamide resin composition according to any one of claims 1, 8, and 9. Recycled polyamide resin; and
comprising mixing glass fibers.
A method for producing a recycled polyamide resin composition according to any one of claims 1, 8, and 9. In claim 11,
A method for producing a recycled polyamide resin composition comprising the step of melt-extruding the mixture. In claim 12,
The step of melt-extruding the mixture is a method of producing a recycled polyamide resin composition using a twin screw extruder with a ratio (Do/Di) of the inner diameter (Di) and outer diameter (Do) of the screw of 1 to 2. In claim 13,
A method of producing a recycled polyamide resin composition, wherein the step of melt-extruding the mixture uses a co-rotating intermeshing twin-screw extruder (TSE).