KR20000018319A - Complex resin reproducing method - Google Patents

Abstract

PURPOSE: A compound resin reproducing method is provided to recycle the reproduced PC/ABS system for a radiator grill material by preventing the degradation of the property by the morphology control using the thermal property of the urethane foam without addition of a generalizing agent. CONSTITUTION: A method comprises the steps of: separating a complex material layer formed by poly vinyl chloride sheet surface layer; foaming urethane foam middle layer; and poly carbonate/acrylonitrile- butadiene-styrene copolymer; pulverizing the separated material; finely pulverizing the firstly pulverized material; sorting the pulverized powder by material; and producing a vehicle radiator grill by extracting the separated, pulverized and sorted material by high temperature and low temperature.

Description

Recycling Process of Composite Resin

The present invention relates to a method for regenerating composite resins, in particular, foamed urethane foams mixed in regenerated PC / ABS systems separated from and recovered from instrument panels of automobiles according to processing temperature conditions. The present invention relates to a regeneration processing method of a composite resin which is intended to apply a regenerated PC / ABS system as an automobile radiator grill material by preventing a large drop in physical properties without adding a compatibilizer.

In general, the automobile production and sales volume is increasing every year due to the development of the industry and the improvement of the standard of living of the people, and the automobile manufacturing technology reaches a considerable level and the durability is long, but the life cycle of the automobile is shortened due to the preference of new cars. Used cars are skyrocketing.

In addition, the use of plastics, which are lightweight materials, is increasing as automobiles are lighter for the purpose of improving fuel economy and reducing emissions.

In other words, the proportion of plastic in automobiles is 32 vol%, which is almost the same as 34 vol% of metal materials, but most of metal materials are recycled, whereas plastic is often used for composite materials such as coating and lamination. This followed.

In addition, the parts made of the composite material is treated as waste and buried or incinerated, resulting in problems such as environmental pollution and the cost used for waste disposal.

Therefore, the recycling method of such plastics is being studied,

First, material recycling, second, chemical recycling, and third, energy recycling can be divided into three types, but these methods point out problems as described below.

First, in the case of re-use as a material, remelting, re-molding thermoplastic resins are regenerated by dissolving, pulverizing, fractionating, mixing, commercializing, and the like, and in the case of plastic composite materials, it is difficult to separate them by material.

Second, chemical recycling is a method of chemically decomposing plastics and recovering them as raw materials. PMMA, PET, and PP are partially processed, but considering the economic feasibility, they have not yet reached the practical stage.

Third, in the method of recovering energy, thermosetting plastics are not dissolved or melted, so it is difficult to recycle them and incinerated and recovered as energy. The calorific value of combustion of plastic is 8,000 ~ 10,000㎉ / ㎏, which is quite high, but there is a problem that requires the removal of harmful substances generated during incineration, energy recovery technology, incineration technology, etc.

Meanwhile, the representative plastic parts that make up a large portion of automobile parts but are difficult to recycle are the instrument panels that form the front of the driver's seat.

The instrument panel is mostly a three-layer pad-type consisting of a polyvinyl chloride sheet in the skin layer, a foamed urethane foam in the intermediate layer, and a polycarbonate / acrylonitrile-butadiene-styrene copolymer. .

Therefore, the recycling of the instrument panel must be preceded by the efficient separation of these components.

However, the urethane foam of the pad layer is inevitably mixed on both sides during the grinding, separation, fractionation and recovery process for recycling, and the mixed urethane foam may greatly affect the physical properties of the recycled PC / ABS system. .

Accordingly, the present invention is to solve the above-mentioned drawback, and is adsorbed on the recycled polycarbonate / acrylonitrile-butadiene-styrene copolymer (hereinafter referred to as PC / ABS) system separated and recovered from the instrument panel of a vehicle. By examining the effect of PU foam on the morphology and mechanical properties of the PC / ABS system according to the processing temperature conditions, a large drop in physical properties was achieved by controlling the morphology using the thermal properties of urethane foam without adding a compatibilizer. The present invention aims to provide a method for reclaiming composite resin that allows reuse of recycled PC / ABS systems as automotive radiator grill materials.

In order to achieve the above object, the present invention provides a skin layer comprising: a polyvinyl chloride sheet, an extra layer is a foamed urethane foam, and a base layer separates a composite material layer consisting of a polycarbonate / acrylonitrile-butadiene-styrene copolymer. Step 1;

A second step of crushing the material separated in the first step; A third step of finely pulverizing the material crushed by the second step; A fourth step of selecting the pulverized powder for each material; The separation, grinding, and sorting of the recovered material at high and low temperatures is characterized in that the fifth step of producing a car radiator grill.

The separated, pulverized and sorted material is recovered by extrusion at 260 ° C to 270 ° C.

1 is a step-by-step showing the regeneration processing method of the composite resin of the present invention,

Figure 2 and Figure 3 is a view showing a change in the form, molecular mobility and functional group of the foamed polyurethane foam according to the extrusion treatment temperature in the process of regeneration of the composite resin of the present invention,

Figures 4a and 4b is a SEM photograph of the fracture surface of each blend in order to compare the foamed polyurethane particle morphology at high and low temperatures,

5 is a representative stress-strain curve when a new PC / ABS and a regenerated PC / ABS blend are tensioned,

6 to 11 is a view showing a change in tensile strength and elongation when extruded new PC / ABS and recycled PC / ABS according to the composition at high and low temperatures,

An embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram showing the regeneration processing method of the composite resin of the present invention step by step, Figures 2 and 3 are the shape, molecular mobility and foamed polyurethane foam (PU) according to the extrusion treatment temperature of the composite resin processing method of the present invention Figure 4a and 4b is a diagram showing the change in functional group, the fracture surface of each blend of SEM in order to compare the foamed polyurethane particle morphology at high and low temperatures, Figure 5 is a new PC / ABS and regeneration Typical stress-strain curves when a PC / ABS blend is tensioned, and FIGS. 6 to 11 show changes in tensile strength and elongation when new PC / ABS and recycled PC / ABS are extruded at high and low temperatures depending on their composition. It is also.

The regeneration processing method of the composite resin of the present invention will be described step by step with reference to FIG.

A first step (S1) of separating the composite material layer made of a polyvinyl chloride sheet, an intermediate layer of a foamed urethane foam, and a base layer of a polycarbonate / acrylonitrile-butadiene-styrene copolymer; A second step S2 of crushing the material separated in the first step; A third step S3 for finely crushing the material crushed by the second step; A fourth step (S4) for selecting the ground powder for each material; The separation, pulverization, and sorting of the recovered material are carried out at a high temperature and low temperature to produce a car radiator grille in a fifth step (S5).

(Experiment)

The regeneration processing step of the composite resin as described above is as follows.

As shown in Figures 2 and 3, it can be seen that the foamed urethane foam starts to refine from 180 ° C and plasticizes after 280 ° C.

Here, the mobility of the hard segment is shown not to depend on the extrusion temperature, whereas the mobility of the soft segment increases linearly with the extrusion temperature from the miniaturization region.

The amine titer began to increase at 180 ° C, once decreased at 260-280 ° C and then rapidly increased above 280 ° C.

That is, the decrease in the amine at the temperature of 260 ~ 280 ℃ is because the amine was consumed by the amine exchange reaction by the amine produced by decomposition.

In addition, the IR absorption strength of the foamed urethane foam decreases gradually as the extrusion temperature increases, which is consistent with the molecular mobility measurement result, suggesting that the urethane foam bond is selectively decomposed at 180 ° C or higher.

Therefore, when heat and high shear force are applied to the foamed urethane foam by using an extruder, a small amount of moisture contained in the foamed urethane foam acts as a powder and decomposes the bond of the foamed polyurethane foam, which forms a network structure, thereby lowering the bond strength. In this case, when the shear force is applied to the urethane foam becomes fine particles.

At this time, if the temperature is further increased, the decomposition of the urethane bond proceeds more rapidly, and the network structure collapses to become a low molecular weight body.

When decomposition progresses to this point, it becomes a plastic body or liquid body with a very low viscosity.

These fine powders, plastic bodies, and liquid bodies have high hydroxyl groups and amine groups, and therefore have high reactivity and can be used as substitutes for modifiers and compatibilizers.

In order to apply the thermal behavior of urethane foam at high temperature and low temperature, the recycled PC / ABS system (containing a small amount of foamed polyurethane foam) and the new PC / ABS system separated from the automotive instrument panel have a high temperature of about 260 ° C and low temperature. Melt blended with a twin screw extruder at approximately 220 ° C.

The foamed urethane foam subjected to high shear stress at a high temperature is finely and evenly dispersed in the molten PC / ABS system by being micronized, gasified, and liquefied in stages. In fact, when the fracture surface of each blend mole is observed by SEM in order to compare the particle morphology of the foamed urethane foam at high temperature and low temperature, as shown in FIG. 4A, the hot melt blend is micronized to 2-3 μm in the PC / ABS matrix. The urethane foam particles are uniformly dispersed.

On the other hand, in the low-temperature melt blend, as shown in FIG. 4B, the urethane foam has a domain having a size of about 30 μm, and thus the dispersion state is not uniform.

In order to investigate the effect of the size and dispersion of urethane foam particles on the physical properties at high and low temperatures, the physical properties such as tensile strength, elongation, flexural strength, flexural modulus, impact strength and hot spot temperature were measured. Comparison was made with each other.

As shown in FIG. 5, new PC / ABS exhibits ductile fracture behavior, while regenerated PC / ABS exhibits brittle fracture behavior, and regenerated PC / ABS exhibits tensile strength, elongation, toughness, and the like. It can be seen that the physical properties are lower than that of the new PC / ABS.

This is because the regenerated PC / ABS contains a relatively large amount of low molecular weight produced by pyrolysis during the regeneration process, and contains a small amount of foamed urethane foam to weaken the interfacial adhesion.

The number-average molecular weight plays an important role in the stress-strain behavior of polymers. If the molecular weight distribution is not wide, the tensile strength and the number-average molecular weight are related.

Where δ is the tensile strength, δ ₀ Is the limiting tensile strength, Μ _e Is the molecular weight between the chains, which can support the above result.

As shown in FIG. 6, there was a marked difference in the tensile properties depending on the composition of the new material and the regenerated material, that is, the molecular weight. If the above equation is extended to general mechanical properties, the higher the amount of regenerated PC / ABS, the lower the molecular weight of PC / ABS produced by pyrolysis, and the lower the physical properties.

Next, the polymer blend has different forces acting between molecules according to the components, and the size, distribution, etc. of the components may be changed depending on processing conditions, and the mechanical properties of the blend are affected by these.

Next, as shown in FIGS. 6 and 7, as the content of the new material increases, the tensile property is increased, and the hot extrudate exhibits almost the same or somewhat higher value in all compositions than the cold extrudate.

This means that the size of the foamed urethane foam particles contained in a small amount of recycled PC / ABS does not significantly affect the tensile properties.

On the other hand, only 100% recycled PC / ABS has sufficient target properties that can be used as a car radiator grille.

8 and 9 show the flexural characteristics, the flexural strength increased with the content of the new material, and the flexural modulus was almost unchanged.

Also, the flexural modulus of the hot and cold extrudate was hardly shown.

From this, it can be seen that the dominant factor affecting the bending characteristics is matrix characteristics rather than domain size.

It can also be inferred that the flexural modulus is more dependent on the characteristics of the molecular structure itself than on the molecular weight.

Next, Figure 10 shows the impact test results of the blend extruded at a high temperature and low temperature, the impact test is a high-speed fracture test to measure the energy required to destroy the specimen. Although slightly different depending on the test method, in order for a specimen to be destroyed by impact, the energy required to initiate the crack and the energy needed to grow the crack are required. Therefore, most of electrons occupy about 70% or more of the breaking energy, and in the case of experimenting with a notch in advance, reproducible results can be obtained without being greatly influenced by the shape of the specimen.

Therefore, in this experiment, the impact strength of the notched specimens was measured by the Izod method.

As with the tensile and flexural properties, the impact strength decreases with the content of reclaimed material.

This is because relatively low molecular weights are present in the regenerated PC / ABS by pyrolysis. Unlike other physical properties, impact strength was significantly different between hot and cold extrudate, but hot extrudate showed up to 66% higher impact strength than cold extrudate.

In general, the smaller the impact strength domain size of the incompatible blends, the higher the trend.

That is, as shown in FIG. 3, the foamed urethane foam particles are dispersed more finely and uniformly by extruding at a high temperature, and it can be explained that the miniaturization of the urethane foam particles caused a synergistic effect of impact strength.

On the other hand, low temperature extrudates containing more than 80% of the recycled material were found to fall short of the target physical properties of the radiator grille.

However, the hot extrudate satisfies the reference value even in the case of 100% regeneration. This difference is because the urethane foam is finely and evenly dispersed in the molten PC / ABS by the progress of micronization, plasticization, and liquefaction at high temperatures as shown in FIGS. 2 and 3.

The heat deflection temperature, or softening point, refers to the maximum limit temperature at which a polymer can be used and maintains its form, which is the actual and important physical property of the polymer.

In the amorphous polymer, the heat distortion temperature is T _g Near and crystalline polymer T _m Become nearby.

As shown in FIG. 11, the measurement results of the heat deflection temperature showed a tendency to increase as the content of the new PC / ABS increased, and the new PC / ABS was about 10 ° C. higher than the regenerated PC / ABS. There was little difference in hot extrudate.

Therefore, PC / ABS containing a small amount of foamed urethane foam regenerated from the instrument panel of automobiles is melt blended at a high temperature of about 260 ° C and a low temperature of about 220 ° C in various compositions with new PC / ABS to apply to a radiator grill. Reviewed.

For example, as the recycled PC / ABS content increases, the mechanical properties decrease, because the low molecular weight is contained in the recycled PC / ABS, and the foamed urethane foam mixed weakens the interfacial adhesion. Analysis of morphology different from the extrusion temperature of the foamed urethane by SEM photograph shows that the hot melt blend is evenly dispersed fine foamed urethane foam particles having a size of about 3㎛, whereas in the low temperature melted blend, the urethane foam has a particle size of 30㎛. As a result, relatively large domains were found.

When urethane foam contained in a small amount of regenerated PC / ABS is subjected to high shear stress at high temperature, decomposition of urethane bonds proceeds rapidly, and the soft segment of urethane is gradually micronized and plasticized, thereby making finer and more uniform particles in the PC / ABS matrix. Will exist.

At this time, the difference in mechanical properties between the hot and cold melt blends was not significant, but the impact strength was significantly improved by up to 66% of the hot blends than the cold blends. In other words, it was found that the tensile and flexural properties were largely dependent on the physical properties of the matrix itself rather than the domain size, and the hot melt blend absorbed the impact energy more effectively because fine urethane particles were evenly dispersed.

Therefore, by recycling the recycled PC / ABS containing a small amount of urethane foam recovered from the instrument panel of the automobile at a high temperature with the new PC / ABS, it is possible to obtain a recycled material having sufficient physical properties applicable to an automobile radiator grill.

As described above, in the present invention, when the PC / ABS recycled material mixed with the foamed urethane foam is extruded at a high temperature, the foamed polyurethane foam receives high shear stress at a high temperature and is finely and uniformly dispersed to reduce the physical properties caused by impurities of the foamed polyurethane foam. By minimizing new materials and using 100% recycled materials, it can be used as a radiator grill material for automobiles, thereby preventing environmental pollution, reducing waste disposal costs, and increasing the added value of recycled materials themselves.

Claims (2)

A first step of separating the skin layer from the polyvinyl chloride sheet, the interlayer from the foamed urethane foam, and the base layer from the composite material layer made of polycarbonate / acrylonitrile-butadiene-styrene copolymer; A second step of crushing the material separated in the first step; A third step of finely pulverizing the material crushed by the second step; A fourth step of selecting the pulverized powder for each material; A fifth step of extruding the separated, pulverized and sorted recovered material at high and low temperatures to produce an automobile radiator grill; Regenerated processing method of a composite resin characterized in that the. The method for regenerating composite resin according to claim 1, wherein the separated, pulverized, and sorted material is extruded at 260 ° C to 270 ° C.