KR100877872B1 - A manufacturing method of recycled resin using resin scrap - Google Patents

Abstract

The present invention relates to a method for producing recycled resin obtained by crosslinking foamed resin scrap, and the recycled resin produced by the method of the present invention is not only superior in terms of packaging and storage of the recycled resin itself, but also its physical properties. Similar to the new material resin, even if it is added to the product in large quantities, it exhibits the same physical properties as the product using only the new material resin, and thus has an excellent economical effect.

Recycling Resin, Sea Bridge, Pellets, Shoe Midsole

Description

Recycling resin manufacturing method using resin scrap {A MANUFACTURING METHOD OF RECYCLED RESIN USING RESIN SCRAP}

1 shows a flowchart of a method for producing recycled resin.

2 shows a schematic view of a recycled resin production apparatus.

3 shows a perspective view of a disc attached to the outlet of a secondary extruder.

Figure 4 is a photograph showing a recycled resin produced by the manufacturing method of the present invention.

<Description of the code>

1 --- disc 2 --- hole

The present invention relates to a method for producing recycled resin obtained by crosslinking foamed resin scrap, and more particularly, to melt melt by primary crosslinking of a resin foam scrap at a high temperature, and to crosslink the melt secondaryly. The present invention relates to a method for obtaining pelletized recycled resin.

Such as shoe midsoles, shoe insoles, layered insulations for automobiles, and automobile parts manufactured from cross-linked resins such as ethylene vinyl acetate (EVA) and / or polyethylene (PE) foam Various resin products and scraps generated during the manufacture of these products are not completely developed for recycling, so they are simply incinerated and used as a heat source, or crushed for other purposes, or in some cases sheeted by forced compression rolling to be recycled. It has been used as a resin.

Among the above applications, the recycled resin used as a sheet is difficult to be packaged due to its large volume, and it is difficult to transport or store and contaminants such as contaminants during storage. Increasing the addition amount of the work had a problem of rapidly falling workability.

The present invention has been made to solve the above problems, the object of the present invention is to produce a recycled resin in the form of pellets can significantly reduce the volume, can be easily transported or stored to prevent contamination by foreign matters In addition, the physical properties of the new material and the resin is almost the same to provide a method for producing a recycled resin with economical efficiency that can increase the amount of recycled resin added during manufacture of the product.

Reclaimed resin manufacturing method according to the present invention

1) milling the foamed resin scraps;

2) first precrosslinking the pulverized resin scrap in a first extruder at a temperature of 250-390 ° C .;

3) pelletizing in a second extruder by adding 3 to 15 parts by weight of a new material resin based on 100 parts by weight of the crosslinked melt;

4) cooling the pellets; And

5) cutting the cooled pellets.

The resin of step 1) may be any one as long as it is in a foamed state, and is preferably ethylene vinyl acetate and / or polyethylene resin.

Step 1) is a step of pulverizing the collected resin scraps to a suitable size before the first preliminary cross-linking, it is preferable to grind to about 20 ~ 45mm size using a grinder. The pulverized resin scrap is put into the first extruder of step 2) below.

Step 2) is a step of primary crosslinking the resin scrap pulverized from step 1) at a high temperature, the first crosslinking temperature is 250 ~ 390 ℃. The primary crosslinking temperature is a temperature at which the crosslinking is performed while preventing the deterioration of the main components of the resin scrap, and is characterized in that the recycled resin is present in a foamed state, which is considerably higher than the degradation temperature of the new material resin. If the temperature is less than 250 ° C, the resin scrap is not completely crosslinked, and if it exceeds 390 ° C, the product itself using recycled resin cannot be manufactured. The reclaimed resin crosslinked using such a high temperature can exhibit physical properties superior to that of the sheet-shaped regenerated resin simply produced by thermocompression bonding.

The melt crosslinked through the primary extruder flows out through the outlet of the primary extruder. In this process, spontaneous ignition occurs and the combustible debris present in the melt is completely burned. This spontaneous ignition phenomenon is because the outlet of the primary extruder maintains a high temperature of 250 ~ 390 ℃, when the melt flows out of the outlet gas is naturally discharged from the scrap component to start the ignition, such a gas material is organic A mixture of peroxide dicumylperoxide (DCP) residue and blowing agent azodicarbonamide (AC) and N, N-dinitroso pentamethylene tetramine (N, N-nirtoso pentamethylene tetramine) residue May occur. Such spontaneous ignition phenomenon completely removes the combustibles among the foreign substances present in the resin scrap, so that the recycled resin has properties similar to those of the new material resin.

Step 3) is a step of mixing the new material resin in the primary crosslinked melt from step 2) and pelletizing it through a second extruder, the preferred process of pelletizing through a second extruder is as follows:

Iii) 3-15 parts by weight of the new material resin is added to the second extruder inlet with respect to 100 parts by weight of the primary cross-linked melt coming out through the first extruder, and the second cross-linked at a temperature of 250-390 ° C .;

Ii) cooling the secondary crosslinked melt to a temperature of 130 to 160 ° C. in a primary cooling device in a secondary extruder;

Iii) heating the melt obtained in step ii) at a temperature of 180-240 ° C. in a primary heating device in a secondary extruder;

Iii) cooling the melt obtained in step iii) to a temperature of 100-120 ° C. in a secondary cooling device in a secondary extruder; And

Iii) pelletizing the melt obtained in the above step iii) by heating it at a temperature of 250-290 ° C. in a secondary heating device in a secondary extruder.

The new material resin may be used according to the use of the product to be manufactured, preferably ethylene vinyl acetate and / or polyethylene resin. The new material resin is preferably used 3 to 15 parts by weight with respect to 100 parts by weight of the melt, when less than 3 parts by weight is added to the new material resin is insignificant, if more than 15 parts by weight is not economical There is a problem.

The various temperatures of the process in the second extruder is a preferred temperature range for obtaining the pelletized recycled resin while keeping the basic physical properties of the recycled resin unchanged. The manufacture of the product becomes impossible.

In step i) of step 3), oil as a modifier may be further added together with the melt and the new material resin from step 2). By adding oil, the recycled resin will perform similarly to the new material resin. The oil may be any known one as long as it can improve the physical properties of the recycled resin, but is preferably a paraffin oil. Preferably, the oil is added in an amount of 3 to 10 parts by weight based on 100 parts by weight of the melt. If it is less than 3 parts by weight, the oil addition effect is insignificant, and when it exceeds 10 parts by weight, it is economically disadvantageous.

The injection port of the second extruder may be provided with a net for filtering the unburned foreign matter in the melt from the primary extruder, whereby the foreign material is not included in the melt introduced into the secondary extruder at all. In addition, the discharge port of the secondary extruder is equipped with a disc (1), the disc has a plurality of through holes (2) to produce a pelletized recycled resin having a diameter corresponding to the size of the through holes from the second extruder.

Step 4) is a step of cooling the long pellet-like recycled resin from the secondary extruder, preferably by dipping the pellet-like recycled resin in water. Preferable water temperature is 5-25 degreeC. The recycled resin on the cooled pellets hardens and leads to the next cutting step.

Step 5) is a process of cutting using a cutter to a size suitable for packaging and storing the cooled pellets on the cooled pellets, preferably cut to a length of 5 ~ 7mm. As a result, the production of granular recycled resin is completed, and the completed recycled resin goes through a packaging process.

Each device in the process of steps 1) to 5) may be sequentially connected and performed in an automated process. In particular, the primary extruder can use two or more, and each outlet of the two or more primary extruders is connected together to the inlet of the secondary extruder.

Hereinafter, the present invention will be described in more detail with reference to Examples.

[ Example ]

One. Recycled resin  Produce

The resin scrap containing ethylene vinyl acetate and polyethylene as a main raw material was crushed to an average size of 30 mm by a mill, and the first preliminary crosslinking was carried out at a temperature of 350 ° C for the first extruder.

6 parts by weight of ethylene vinyl acetate and 4 parts by weight of low-density polyethylene were added to the secondary extruder inlet with respect to 100 parts by weight of the primary crosslinked melt from the first extruder, and the second crosslinked at 350 ° C. And melt the secondary crosslinked melt to a temperature of 150 ° C. in the primary chiller in the secondary extruder, and then to a temperature of 200 ° C. in the primary heater in the secondary extruder, Cooled to a temperature of 110 ° C. in a secondary cooler and finally pelletized by final heating to a temperature of 260 ° C. in a secondary heater in a secondary extruder.

The pellets coming out from the secondary extruder were cooled with water at 20 ° C. and cut into 5 mm sizes to prepare recycled resin.

Material (part by weight) Resin Resin New material resin Ethylene vinyl acetate 6 60 Low density polyethylene 4 40 Resin Resin 100 -

2. Resin Resin Foam  Produce

Each component was added in the amounts shown in the following Table 2 with respect to the obtained resin and 100 parts by weight of the new material resin to obtain a recycled resin foam (Example) and a new material resin foam (Comparative Example).

Ingredients (parts by weight) Example Comparative example CaCO ₃ 20 20 Azodicarbonamide 10 10 DCP (dicumylperoxide) One One Stearic acid 1.2 1.2 ZnO 1.5 1.5 Carbon black 0.5 0.5

3. Property measurement

Ethylene vinyl acetate sponge was prepared from the recycled resin foam (Example) and the new material resin foam (Comparative Example) obtained in the above 2, and the physical properties were measured, and the results are shown in Table 3 below.

Test Items unit result Test Methods Example Comparative example Strength (C-Type) Scale 26 ± 1 27 ± 1 KS M 6518 The tensile strength kg / cm ³ 9 10 KS M 6518 Elongation % 143 125 KS M 6518 importance g / cc 0.06 0.06 KS M 6519 Shrinkage % 1.0 1.0 Aging oven (70 ℃, 40 minutes)

As shown in Table 3, when comparing the physical properties of the examples using the new material resin and the recycled resin with the comparative example using only the new material resin, the physical properties were almost the same in strength, tensile strength, specific gravity and shrinkage. In elongation rate, it turned out that the result was more excellent than the comparative example.

As described above, the recycled resin produced by the manufacturing method of the present invention, as well as the superiority of the packaging and storage of the recycled resin itself, its physical properties are similar to the new material resin, even if a large amount is added to the resin product product using only the new material resin It shows the same degree of physical properties as the economic effect is excellent.

Claims (6)

Reclaimed resin manufacturing method comprising the following steps: 1) grinding ethylene vinyl acetate or polyethylene resin scrap; 2) first precrosslinking the pulverized resin scrap in a first extruder at a temperature of 250-390 ° C .; 3) obtaining pellet through the steps i) to v) below; Iii) 3-15 parts by weight of the new material resin is added to the second extruder inlet with respect to 100 parts by weight of the primary crosslinked melt from the first extruder, and the second crosslinked at a temperature of 250 to 390 ° C., Ii) cooling the secondary crosslinked melt to a temperature of 130 to 160 ° C. in a primary cooling device in a secondary extruder, Iii) heating the melt obtained in step ii) at a temperature of 180-240 ° C. in a primary heating device in a secondary extruder, Iii) cooling the melt obtained in step iii) at a temperature of 100-120 ° C. in a secondary cooling device in a secondary extruder, and Iii) pelletizing the melt obtained in step iii) by heating at a temperature of 250-290 ° C. in a secondary heating apparatus in a secondary extruder; 4) cooling the pellets; And 5) cutting the cooled pellets. delete delete The method of claim 1, wherein the new material resin in step 3) is at least one of ethylene vinyl acetate and polyethylene. The method of claim 1, wherein the oil is further added in step i) of step 3). 6. The method of claim 5, wherein the oil is liquid paraffin.

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