Low-melting point granules prepared from foamed non-linked polypropylene, method and apparatus for manufacture thereof

FIELD: optionally materials.

SUBSTANCE: granules with melting point 125-140°C are obtained by extruding non-linked random copolymer of propylene with nucleating agent through tandem-extruder, in which each of extruders is divided into sic temperature zones with specified temperatures. Thus manufactured granules show low melting point, satisfactory mechanical strength, and contain at least 80% of closed cells.

EFFECT: improved moldability into a variety of packaging items.

18 cl, 19 dwg, 10 tbl, 30 ex

The technical field

This invention relates to granules of foamed seamless polypropylene having a melting point of from 125 to 140°With, the method of production of these pellets, the device for implementing this method and the product formed from the foam.

Prerequisites to the creation of inventions

Due to the excellent mechanical strength and elastic properties, foam polypropylene resin is widely used as a packaging material, building material, thermal insulation material and the like. However, since polypropylene has a high degree of crystallinity, low melt viscosity and is difficult merging, it is very difficult to obtain a highly foamed product made of polypropylene.

U.S. patent No. 5527573 (issued June 18, 1996) discloses an extruded foam polypropylene resin with the closed cells and several ways of obtaining this foam. Foam for U.S. patent is a form of the strap and the area of the minimum cross-section of about 5×2,54 square centimeters, the minimum thickness of 12.7 mm and a density of about 0.08 g/cm³. The form and properties make it difficult molding foam products in desired forms. U.S. patent No. 6051617 (issued April 19, 2000) discloses a particle foamed polypropylene resin suitable for molding foamed f is Romanovo products and how you can get it. However, the particle foamed polypropylene resin obtained by grafting vinyl co monomer to the particles of polypropylene resin, to obtain particles of the modified copolymer resin, and a foaming particles modified copolymer resin. U.S. patent No. 6077875 (issued June 20, 2000) discloses foamed and expanded beads of polypropylene resin for molding obtained from unstitched statistical copolymer of propylene-ethylene. Foam balls for U.S. patent content of open cells at most 40%, more preferably 25%, and have a melting point of at least 141°C.

Description of the invention

Seamless polypropylene resin is advantageous because it can be reused, and granulated foam obtained from the resin, is easily moldable. However, the granulated foam obtained by extrusion of seamless polypropylene resin, contains a lot of open cells and is therefore unsuitable. For its practical application granulated foam must contain a large number of closed cells for mechanical strength. Worldwide only JSP Corporation Japan successfully commercially produces granulated foam from a seamless polypropylene resin. However, although it is known that granulated foam from nesseth is polypropylene, having a low melting point, is very useful, thanks to its easy formemost and excellent re-use, granulated foam from a seamless polypropylene having a melting point of 140°and less still is not performed.

Therefore, the purpose of this invention is to obtain granules of foamed seamless polypropylene resin with a melting point 140°With or below, which is obtained from a seamless polypropylene resin to guarantee the possibility of re-processing, which has a high content of closed cells, to provide a satisfactory mechanical strength, and which can be molded into various molded packaging materials, and method of reception. The authors present invention successfully produce a granulated foam from a seamless polypropylene with a melting point of from 125 to 140°that contain at least about 40% of closed cells, using a tandem extruder with multiple temperature zones, specifically with variable temperature, by creating a melt flow seamless polypropylene resin having a melting point of 138-140°through temperature zones, mechanical homogenization of the melt polypropylene resin passing through such zone at a lower temperature from 120 to 130°With extensions homog dozirovannogo melt when passing under pressure through the many holes, formed in filero, and cutting the extended pins unloaded their holes dies.

In one aspect this invention relates to granules of foamed seamless polypropylene having a melting point of from 125 to 140°C.

In another aspect, the invention relates to a method for producing granules from seamless foamed polypropylene having a melting point of from 125 to 140°containing stages: (a) extruding seamless polypropylene statistical copolymer having a melting point of 138 to 140°through a tandem extruder, which consists of the first extruder, is divided into the first temperature zone, where the set temperature from 147 to 153°With the second temperature zone, where the set temperature from 167 to 172°With, a third temperature zone, where the set temperature of from 168 to 172°C, the fourth temperature zone, where the set temperature from 218 to 225°C, fifth temperature zone, where the set temperature from 197 to 203°and the sixth temperature zone, where the set temperature from 188 to 193°C, the second extruder is divided into the first temperature zone, where the set temperature from 167 to 173°With the second temperature zone, where the set temperature of 147 up to 152°With, a third temperature zone, where the base is t the temperature from 142 to 147° With the fourth temperature zone, where the set temperature from 137 to 141°C, fifth temperature zone, where the set temperature from 137 to 142°and the sixth temperature zone, where the set temperature from 132 to 137°With, the guide part connecting the first extruder to the second extruder, where the set temperature of from 248 to 255°With; (b) the implementation of the forced flow of extrudable material at a temperature of from 125 to 140°using pumping pump; (C) homogenization of material processed at a temperature of from 120 to 130°With; (d) expansion of the homogenized material through a Spinneret and (e) cutting the expanded material, to obtain a granulated foam.

In another aspect this invention relates to a device for producing granules from seamless foamed polypropylene having a melting point of from 125 to 140°C.

In another aspect this invention relates to molded products made of granules of foamed seamless polypropylene having a melting point of from 125 to 140°C.

Brief description of drawings

These and other objectives, features and other advantages of this invention will be more clearly understood from the following detailed description presented together with the accompanying drawings, where:

Figure 1 is a view, dormancy is prevailing throughout the structure of the device for producing granules of foamed seamless polypropylene in accordance with this invention;

Figure 2 is a view in plan, showing the cylinder of the first extruder, shown in figure 1;

Figure 3 is a view in section, taken along the line A-a in figure 2;

4 is a schematic view showing the structure of the device for feeding CO₂;

5 is a view in section, showing the internal structure of the pump and homogenizing parts shown in figure 1;

Figa and FIGU - front views showing two different parts homogenizing;

Fig.7 is a view in plan showing the structure of spunbond parts shown in figure 1;

Fig is a view in section, taken along the line b-b In Fig.7;

Fig.9 is a view in section, taken along the line C-C in Fig;

Figa - side view showing the cylinder spunbond part on which is mounted cooling unit;

Figw - front view figa;

11 is a DSC curve of granular polypropylene foam (example 1)obtained according to this invention;

Fig - DSC curve of granular polypropylene foam (example 2)obtained according to this invention;

Fig - DSC curve of the copolymer RP2400 (polypropylene-polyethylene (3%), which is used for producing granulated polypropylene foams according to this invention;

Fig shows the FT-IR analysis of granular polypropylene foams obtained according to this invention;

Fig shows FT-IR analysis of the copolymer RP2400 (polypropylene-polyethylene (3%)), used to obtain granulated polypropylene foams according to this invention;

Figa - photograph taken by an optical microscope at magnification X100 and showing granular polypropylene foam obtained according to this invention;

Figw - photograph taken by an optical microscope with magnification h and showing granular polypropylene foam obtained according to this invention.

Similar reference numbers refer to similar parts in the various views of the drawings.

The preferential variant of the invention prior to the present invention was impossible to obtain a granulated foam, having a melting point 140°With or below. Pure polypropylene, melting point 138 which°could not be processed at a temperature of 138°With or below, as it was quickly utverjdala would at a temperature of its melting point or lower. Therefore, it was also considered that it is impossible to obtain a granulated foam, having a melting point 140°With or below.

However, the authors of this invention have developed granules of foamed seamless polypropylene, which have a melting point 140°s or less and the content of open cells about 20% or less. Such foamed granules were developed by combining and applying multiple is drity. For example, it was found that the content of open cells in the foam can be significantly reduced when using the tandem extrusion as the basis, specific temperature conditions for the first and second processes of extrusion and homogenization of the melt from the extruder at a lower temperature from 125 to 130°C. has also been Found that only when the temperature during extrusion and expansion seamless polypropylene resin having a melting point of 138 to 140°With support in a specific temperature range, can be formed of closed cells in the amount of 80% and more. In addition, we discovered that the melting temperature of the foam obtained from a seamless polypropylene resin having a melting point of 138 to 140°may be reduced to 138°or lower due to certain conditions of processing according to this invention.

What follows is a more detailed description of the method of obtaining a granulated foam from a seamless polypropylene according to this invention. The way of getting this invention contains the stage of extrusion, pumping pump, homogenization, expansion and granulation.

(1) Extrusion

The process of extrusion according to this invention can be implemented with the help of the tandem extruder, which is widely used and known in the art for receiving pins as the basis or its variant. The materials used for producing granulated foam from a seamless polypropylene according to this invention contain seamless polypropylene statistical copolymer having a melting point of from 138°to 140°With, a nucleating agent, a foaming agent and an additive, if necessary.

The main resin in this invention is a seamless polypropylene statistical copolymer having a melting point of 138 to 140°C. other Examples of co monomer, copolymerizable with propylene include ethylene, 1-butene, 1-penten and 1-hexene. Propylene statistical copolymer can be biopolymer, such as a statistical copolymer of propylene-ethylene or a statistical copolymer of propylene-butene or ternary copolymers such as the copolymer of propylene-ethylene-butene. The relative share of the other co monomer other than propylene in the copolymer is preferably from 0.05 to 10% by mass.

The nucleating agent operates so that dispersing the foaming agent and adjust the cell size of the foams. Examples of the nucleating agent, which can be used in this invention include, but are not limited to, sodium bicarbonate, sodium carbonate, potassium bicarbonate, carbon is tons of potash, ammonium bicarbonate or ammonium carbonate. The preferred sodium bicarbonate. The greater the amount of nucleating agent used, the smaller the cell size of the foams. On the contrary, the smaller the amount of nucleating agent used, the larger the cell size of the foams. In this invention using from 0.1 to 0.4% of a nucleating agent based on the weight of the resin. When the amount of nucleating agent used exceeds 0.4%, may be unsatisfactory dispersion or agglomeration and, as a result, the cell grows larger than the specified size. On the contrary, when the amount of the nucleating agent is 0.1% or less, the activity of nucleation is extremely weak, resulting in cell diameter cannot be reduced.

As a blowing agent in the present invention is applicable to organic and inorganic foaming agents. Examples of the organic foaming agent are aliphatic hydrocarbons, such as propane, butane, hexane and heptane, alicyclic hydrocarbons such as CYCLOBUTANE and cyclopentane, halogenated hydrocarbons, such as chloroformate, triptorelin, 1,1-differetn, 1,2,2,2-Tetrafluoroethane, methyl chloride, ethylchloride and methylene chloride. In addition, the applicable organic pore-formers include dichlorotetrafluoroethane, trichlorotrifluoroethane, try armanitola, DICHLORODIFLUOROMETHANE, dichloromonofluoromethane and dibromotetrafluoroethane. For reasons of capacity for processing by molding, nontoxicity and protection against fire these ferroresonance hydrocarbons are preferred. These organic foaming agents can be used singularly or as a mixture of two or more of them. Examples of the inorganic foaming agent include nitrogen, carbon dioxide, argon and air. These inorganic foaming of Agneta can be used singularly or as a mixture of two or more of them. Additionally, there may be used any mixture of randomly selected two or more organic and inorganic foaming agents. The most preferred foaming agent is an inorganic foaming agent, as they do not destroy the ozone layer and budget. The used amount of a blowing agent depends on the degree of expansion of the foam granules, which should be achieved and the type of resin and foaming agent. The amount of blowing agent used in this invention is from about 0.1% to 0.4% by weight based on the weight of resin.

In addition can be used various kinds of additives. Examples of such additives include an antioxidant, a UV absorber, a flame retardant, a coloring agent, dye, detect water metal and the like. These additives can be used in an amount of from 0.1 to 0.3% by weight based on the weight of copolymer resin. In a preferred embodiment of the present invention using paraffin wax. He contributes to the fluidity of the copolymer resin and acts as an antistatic agent, eliminating static electricity copolymer resin. The amount of paraffin wax is about 0.1% by weight.

The materials used in this invention, ekstragiruyut tandem extruder, which set specific physical condition according to this invention, and the method will be described next. Tandem extruder consists of a first extruder, a second extruder and a guide part connecting the first and second extruders. The compression screw is usually 3:1. Usually, the internal diameter of the cylinder of the first extruder is from about 60 to 70 mm, an Inner diameter of the cylinder of the second extruder is typically from about 90 to 95 mm

The first extruder is divided into six zones according to their temperatures, each zone corresponds to 300-400 LD. Six zones are first temperature range from 148 to 153°With the second temperature zone from 167 to 172°With, the third temperature zone from 167 to 172 °With the fourth temperature range from 218 to 223°C, fifth temperature range from 197 to 203°and the sixth temperature zone from 188 to 193°C.

Smo is the seamless polypropylene statistical copolymer and a nucleating agent serves at constant speed through the hopper and then melted in the first temperature zone, where the set temperature of from 148 to 153°C. the flow Rate can be adjusted by the rotation speed of the screw, and it is usually equal to about 20 to 30 Rev. in minutes This screw rotation speed determines the speed of flow of the source material and the flow rate of the melt. In this case, the speed of flow of the resin is about 25 km/h. Although copolymer resin and the nucleating agent can be introduced through one hopper at the same time, preferably when they are served independently through separate hoppers. The second and third temperature zones support at a temperature of from 167 to 172°With, other additives such as paraffin wax, introducing the starting point of the third temperature zone. Paraffin wax, which must be entered, is pumped by the pump after it melts. The fourth temperature zone set up 218-223°and the foaming agent is fed to the initial point of the fourth temperature zone by the pumping operation of the pump. The melt from the fourth temperature zone is passed through the fifth temperature zone, where the set temperature from 218 to 223°and then injected in the sixth temperature zone, where the set temperature from 188 to 193°C.

The melt from the sixth temperature zone of the first extruder is introduced into the second extruder along the guide parts and, connecting the first and second extruders. Here the temperature of the guide details set to 248-255°and LD of the guide parts is 300-400 mm

The second extruder is also divided into six zones in accordance with the temperature of each zone corresponds 470-520 mm Six zones are first temperature area from 168 to 173°With the second temperature area from 147 to 152°With, the third temperature zone from 143 to 147°With the fourth temperature range from 137 to 142°C, fifth temperature range from 137 to 142°and the sixth temperature zone from 132 to 137°C. the Speed of the screw of the second the extruder typically from 8 to 12 Rev. in minutes

Each zone in the first and second extruder can be maintained at a specific set temperature by any method type water cooling, oil cooling or type of air cooling. Of these the preferred method of water cooling, which adjusts the temperature by using water pressure. For example, there may be used the device, water cooling, which has a body of cooling water, which gives a hollow shape, so that it can be mounted around the cylinder of the extruder, and the cylinder is inserted, and is provided with a passage for cold water, formed together with the casing so that the cooling water is in contact directly with the surface the capacity of the cylinder.

(2) Pumping pump

Sixth temperature zone of the second extruder can match the flange for attaching devices for crushing melt according to the method according to this invention. Because maintaining the temperature of the flange when 132-137°With this invention is unusual and this temperature is lower than the melting point 138°With polypropylene resin, the flow rate of the melt can be significantly reduced. Therefore, it is necessary to force the melt flow, so that he could move smoothly. This forced flow can be created through the pump. At this time, the temperature of the support at 125-138°device With water cooling.

(3) Homogenizing

According to this invention, the melt is withdrawn from the extruder pumping by the pump at a temperature of from 125 to 140°C, homogenized at a temperature of from 120 to 130°C. Here homogenize means that the melt is cut and milled at the same time like grinding stones. Also, during the homogenization temperature of the melt becomes uniform in the inner part and outer part. During homogenization temperature in the cylinder is supported at 120-130°With, preferably by a method of the type water-cooling or type of oil cooling, preferably by the method of oil ohla the Denia. At this time, the pressure inside the cylinder reaches about 120 kgf/cm².

(4) Extension

Homogenized melt extend through a Spinneret. As described above, since the pressure inside the cylinder, in which the melt is homogenized, reaches about 120 kgf/cm²install a decompression device when filero to maintain a pressure of 0.3 to 0.7 kgf/cm². Polypropylene resin extend through the openings of nozzles. Here, the diameter of each hole is usually from 0.5 to 1.0 mm, the relative expansion generally equal to five times the diameter of the holes.

(5) Granulation

Foam formed extending through the openings of nozzles, unload and simultaneously cut cutting parts, to obtain granulated foam.

Device for producing granulated foam seamless polypropylene, which have a melting point of from 125 to 140°Since, according to this invention contains a first extruder, a second extruder connected to the first extruder, pump, attached to the second extruder, homogenizing the part attached to the pumping part, and spunbond part attached to the homogenizing part.

The first extruder comprises a cylindrical housing having a screw mounted therein for rotation, driving means located on the line is e cylinder, for augers and many cooling devices and heating devices located on a circle on the surface of the cylinder, and provided with inlet openings for the supply of polypropylene and a nucleating agent in the cylinder at the end portion of the cylinder near the driving means, and inlets for feed additives, such as antistatic agent, and foaming agent in the respective middle part of the cylinder and the outlet at the other end portion of the cylinder. Polypropylene and a nucleating agent, are fed into the cylinder through the inlet opening, forcibly transported toward the outlet by a screw, which rotates the driving means.

A second extruder connected to the first extruder guide part includes a cylinder through which the guide part serves a melt of polypropylene, discharged from the cylinder of the first extruder, and a variety of cooling devices and heating devices located on the outer surface around the circumference of the cylinder, for adjusting the temperature of the melt in the cylinder.

The pump part to the forced displacement of molten polypropylene discharged from the second extruder, the following device includes a housing having an inner space, which serves the molten polypropylene, wygraj is Amy from the cylinder of the second extruder, a pair of gears mounted for rotation in the housing, and gears meshed with each other, and driving means for rotating the gears.

Homogenizing part contains the first cylindrical body, which serves the molten polypropylene, discharged from the cylinder of the pump part, the first housing is mounted for rotation, driving means for rotating the first housing, the auger is connected to the discharge end of the first casing, the second casing is placed around the screw, covering housing, mounted on the outer circumference of the second housing for forming an airtight space between the second housing and the cover housing. Spiral gap formed between the auger and the second housing along the entire length of the screw, and the molten polypropylene discharged from the first housing, flows through it to be unloaded, and is discharged to the outside. Heat-transfer oil flows into the gap formed between the second body and a covering body for regulating the melt temperature of the polypropylene, which flows through the second body.

Homogenizing part contains a homogenizing device that uniformly pulverized melt polypropylene. Homogenizing device consists of a rotating plate mounted with the possibility of rotating the tion, and a fixed plate located so as to be in contact with the rotating plate. The rotating plate is equipped with a number of slits arranged radially, and the fixing plate is equipped with a number of round holes. The molten polypropylene, supplied in homogenizing the part that goes to the rotating plate and is cut by the edge of each hole of the rotating plate, as he passes through the rotating plate. Then cut the molten polypropylene is crushed rotating plate in the gap between the rotating plate and the fixed plate.

Chopped melt polypropylene, leaving the homogenizing part, serves to draw the part, including the discharge part, the cutting part and the driving means, where advanced foam cut to specified dimensions.

In this invention the cooling device mounted on the cylinders of the first and second extruder, have a closed shell, through which flows supplied from the outside, the cooling water. Cooling water is introduced into the shell, flows through the shell being in contact with the surface of the cylinder, due to which the temperature of the melt that flows inside the cylinder decreases. In heating devices located between the two shells, used heater having a heating JV is Rahl, installed in it.

The cylinder of the first extruder is divided into six zones according to the temperature condition, which should satisfy the melt of polypropylene, the current in the cylinder. The temperature of each zone regulate cooling devices or heating devices mounted on the outer circumference of the cylinder. The melt temperature of the polypropylene in the first temperature zone should be maintained at 147-153°With, in the second temperature zone at 167-172°With, in the third temperature zone 168-172°and the fourth temperature zone when 218-225°With, in the fifth temperature zone at 197-203°and the sixth temperature zone at 188-193°C.

The second cylinder of the extruder is also divided into six zones according to the temperature condition, which should satisfy the melt of polypropylene, the current in the cylinder. The temperature of each zone regulate cooling devices or heating devices mounted on the outer circumference of the cylinder. The melt temperature of the polypropylene in the first temperature zone should be from 167 to 173°With, in the second temperature zone from 147 to 152°With, in the third temperature zone from 142 to 147°With, in the fourth temperature range from 137 to 141°With, in the fifth temperature range from 137 to 142 °and the sixth temperature zone from 132 to 17° C.

The guide part connecting the first extruder and the second extruder should be maintained at a temperature of from 248 to 255°C.

Two pulleys located in the internal space of the pump casing parts rotate in opposite directions towards the center of the internal space, to force the molten polypropylene to move to the next position in the process. Also the first building homogenizing part is supported rotatably supporting plates with many bearing blocks. Sprocket of the driving device coupled with the driven sprocket attached to the outer surface circumference of the first housing so that the first housing is rotated in response to operation of the vehicle.

The unloading part of the spunbond part includes a hollow guide the barrier and the cylinder located outside of the guide barriers. Guide barrier has many cavities formed on its outer circumference in the longitudinal direction of the guide barriers. The molten polypropylene, leaving the homogenizing part, flows through each cavity. Many through holes formed on the parts of the cylinder corresponding to the cavities, respectively.

The cutting part spunbond part includes a support plate placed on C the day side of the discharge part, and cutting the part attached to the base plate and placed with the possibility of movement on the outside of the cylinder. The cutting part has multiple through holes formed at positions corresponding to the multiple through holes on the cylinder, respectively. The driving means include Cam, which can be brought into rotation by the motor, a crank connected with the eccentric and rotatable in response to rotation of the eccentric, and converting and transmitting energy devices connected to the crank, to convert the rotational motion of the crank into a linear movement and transmitting the linear movement of the support plate is attached to the cutting part, thereby cutting details are given in reciprocating movement along the outer circumference of the cylinder by operating the driving means, and enhanced foam of the through holes of the cylinder are cut edges of the through holes of the cutting part.

Meanwhile, the cylinder is equipped with a number of grooves made in the longitudinal direction at a predetermined position. Each groove has a rod placed in her ability reciprocating motion, one end of which is attached to the base plate. The cutting part is attached to each reciprocating movement of the rod saimn the m device and is driven in a reciprocating movement on the outer circumference of the cylinder of the reciprocating motion of the rod, which is driven in a reciprocating motion along each groove of the cylinder.

Now, specific structure and operation of the device for the production of granular foams according to this invention will be described in more detail in conjunction with accompanying drawings.

Figure 1 is a view showing the entire structure of the device for the production of granular foams according to this invention. Device for the production of foams according to this invention contains the first extruder 100, the second extruder 200 is connected to the first extruder 100 through the guide part 150, the pump part 300, is attached to the second extruder 200, homogenizing portion 400 that is attached to the pumping unit 300, and spunbond part 500 for forming a mixture of foam, leaving the homogenizing part 400, granulated foam. Here the relevant part referred to above, will be described separately.

A. the First extruder 100

Figure 2 is a view in plan, showing the cylinder of the first extruder 100, shown in figure 1, and figure 3 is a view in section, taken along the line A-a in figure 2. These figures show the structure of the first extruder 100. The first extruder 100 comprises a cylindrical housing 101 having a specific length, the driving means 102, mounted on the end of the cylinder 101, the screw 103, mounted in qi is Indra 101 and driven in rotation driving means 102, and the cooling device 104 and the heating device 105 mounted on the outer surface around the circumference of the cylinder 101.

On the end portion of the cylinder 101 near the vehicle 102 is formed inputs 101a, 101b (only one input 101A shown in figure 3, which represents a view in sectional view) for the filing of the original polypropylene and a nucleating agent (for example sodium bicarbonate) into the cylinder 101, respectively. Output is formed on another end portion of the cylinder 101. Also on the middle part of the cylinder 101 formed the entrance 101d for submission of antistatic agent (e.g. paraffin wax) and entrance e for supplying a blowing agent (e.g. LPG or CO₂).

On the other hand, the inside of the cylinder 101 is divided into six temperature zones corresponding to the temperature conditions of polypropylene, which is fed to the cylinder 101. The cooling device 104 and the heating device 105 mounted on the outer surface around the circumference of the cylinder 101 at positions corresponding to the specified temperature zones, to control the melt temperature of the polypropylene.

Figure 2 is a view in plan showing the cooling device 104 and the heating device 105 mounted on the outer surface around the circumference of the cylinder 101 of the first extra Dera 100 shown in figure 1. Now cooling etc is sposobleny and heating devices will be explained in more detail with reference to figure 3.

The cooling device 104 mounted on the outer surface around the circumference of the cylinder 101 corresponding to each zone, have airtight shell ring shape through which flows the cooling water supplied from an external source. Cooling water is introduced into the shell 104, flows through the shell 104 being in contact with the surface of the cylinder 101. Therefore, the temperature inside the cylinder 101, that is, the melt temperature of the polypropylene, which flows in it, may be reduced.

Heating devices 105, mounted between the two shells 104 (i.e., between the cooling devices) is a heater installed in the heating coil. The heating device to increase the melt temperature of the polypropylene, which had been reduced cooling devices 104, to a predetermined temperature.

The first extruder 100 having the structure described above will be described with reference to the relevant drawings. When the driving means 102 activate, polypropylene and a nucleating agent serves in the cylinder 101 through the input 101A, 101b, respectively. Auger 103 is rotated in the cylinder 101 under the action of the driving means 102 (of course, screw rotation speed lower than speed vehicle speed reducer), what redstem which the polypropylene and a nucleating agent, supplied to the cylinder 101, melted and mixed, while forcibly moving towards the other end of the cylinder 101.

In the process, which is described above, the antistatic agent and the foaming agent is fed into the cylinder 101 through other inputs 101d, e formed on the middle part of the cylinder 101 to mix them with the melted polypropylene.

As described above, the cylinder 101 of the first extruder 100 is divided into six temperature zones Z1-Z6 corresponding to the temperature condition of the melt of polypropylene, which flows into them, as shown in figure 2. Each temperature zone Z1-Z6 has a length of from about 300 to 400 mm In a preferred aspect, the cylinder 101 has an inner diameter of 65 mm and LD of about 358 mm and the temperature condition and the other conditions of the melt of polypropylene, corresponding to each temperature zone Z1-Z6 of the cylinder, such as the following:

1) the First temperature zone Z1: Zone, which serves polypropylene and a nucleating agent, which is supported at a temperature of 150°S, the length of which to provide the specified temperature, that is, the length of the first temperature zone Z1 is equal to 360 mm

2) the Second temperature zone Z2: Melt polypropylene, the current through the second temperature zone Z2, support at a temperature of 170°C.

3) the Third temperature zone Z3: Melt polypropylene, the current through a third temperature of the second zone Z3, support at a temperature of 170°that is the same as the second temperature zone Z2. Paraffin wax as an antistatic agent serves in the third temperature zone Z3.

4) the Fourth temperature zone Z4: Melt polypropylene, the current through the fourth temperature zone Z4 support at a temperature of 220°C. CO₂or LPG as a blowing agent serves in the cylinder 101 in the fourth temperature zone Z4.

5) the Fifth temperature zone Z5: Melt polypropylene, the current through the fifth temperature zone Z5 support at a temperature of 200°C.

6) Sixth temperature zone Z6: Melt polypropylene support at a temperature of 190°C.

In order to meet the temperature conditions of the melt of the polypropylene in the respective temperature zones Z1-Z6, the cooling device 104 and the heating device 105 mounted on the temperature zones, uses properly. That is, the melt temperature of the polypropylene in the respective temperature zones Z1-Z6 are adjusting to meet the condition specified above, by regulating the amount and temperature of the refrigerant supplied into the shell of the cooling devices 104, or current applied to the heating wire forming the heating device 105, and the time for the current.

Another from the pile, in the case of the use of CO₂as a blowing agent, which is fed to the cylinder 101 of the first extruder 100, use an additional device for feeding CO₂. Device for feeding CO₂used in this invention is as follows.

Referring to figure 4, which is a schematic view showing the structure of the device for feeding CO₂the device 110 for feeding CO₂contains a reservoir 110A to store CO₂the section for evaporation and freezing 110V, section for feeding CO₂110C, section for stabilization 110D and a section for storing E. CO₂stored in the tank 110A to store CO₂transmit section 110V to evaporation and freezing, where it is converted into the vapour phase. That is, while passing through the refrigerated section 110V to evaporation and freezing of CO₂gasified, and evaporates and then it is served in section 110D to stabilize the pump section 110S for filing CO₂. In section 110D for the stabilization of the CO₂in the form of steam is turned into the gas phase. CO₂in the gas phase is stored in a section E for storage. When the process starts, CO₂stored in the partition E to store, served in the first cylinder 101 of the first extruder 100, described above.

The melt of polypropylene, which is in contact with the temperature conditions in the temperature zones Z1-Z6, move (move auger 103) towards the end of the cylinder 101 and then fed to the second extruder 200 through the guide part 150. The molten polypropylene through the guide part 150, a support at a temperature of 250°C.

C. a Second extruder 200

The second extruder 200, in which the molten polypropylene is fed through the guide part 150 has the same structure as the first extruder 100. That is, the cylinder 201, forming a second extruder 200 is divided into six temperature zones corresponding to the temperature condition of the melt of polypropylene, which flows into the cylinder 201. Cooling device and a heating device mounted on the outer surface around the circumference of the cylinder 201 at positions corresponding temperature zones, to control the melt temperature of the polypropylene.

Cooling device and the heating device have the same structure as the cooling device 104 and the heating device 105 mounted on the outer surface around the circumference of the cylinder 101 of the first extruder 100, shown in figure 2. Therefore, the description of the structures of the cooling device and the heating devices are excluded.

The cylinder 201 of the second extruder 200 is divided into six temperature zones corresponding to the temperature condition of rspl the VA polypropylene, which flows in them. Each temperature zone has a length of from about 470 to 520 mm In a preferred aspect, the cylinder 201 has an inner diameter of 90 mm and LD of about 495 mm Temperature molten polypropylene in the cylinder 201 in the temperature zones the following:

1) the First temperature zone (part of entry): 170°C.

2) the Second temperature zone: 150°C.

3) the Third temperature area: 145°C.

4) the Fourth and fifth temperature zone: 140°C.

6) Sixth temperature zone (at output): 135°C.

C. the Pump part 300

The molten polypropylene at a temperature of 135°discharged from the second extruder 200, serves in the pump part 300. Since the melting point of the polypropylene 138°C, the molten polypropylene discharged from the second extruder 200, has significantly reduced the flow rate. In this invention the pump part 300 is used for forced displacement of such a melt of polypropylene in the following process.

Figure 5 is a view in section, showing the internal structure of the pumping unit 300 and homogenizing part 400 shown in Fig 1. The left side shows the internal structure of the pumping unit 300, and the right side shows the internal structure of the homogenizing part 400, respectively.

The pump part 300, which serves the molten polypropylene with you is raemy from the cylinder 201 of the second extruder 200, contains shell 301, having an internal space, a pair of gears A and B, linked and installed rotatably in the inner space of the casing 301 and the driving means 303 for rotating the gears A and B. The input part of the membrane 301 is connected to the cylinder 201 of the second extruder 200 flange 304.

The molten polypropylene, discharged from the cylinder 201 of the second extruder 200, serves in the inner space of the shell 301 via the input part and then forcibly discharged to the output of the two gears A and B, which rotate in opposite directions towards the center of the inner space of the shell. The molten polypropylene, discharged from the cylinder 201 of the second extruder 200, has a temperature of 135°and significantly reduced turnover. Therefore, the pump part 300 is used in order to force the molten polypropylene to the next process.

D. Homogenizing part 400

Homogenizing part 400 is connected to the output part of the shell 301 pumping unit 300, divided into the rotating part 400A and chopping part of 400V. The rotating part 400A is composed of the first housing 401 hollow cylindrical shape, the driven sprocket 402 attached to the outer surface of the first housing 401, and the driving means 404, attached to leading vezdochka 403.

The first housing 401 is supported rotatably supporting plates 407 and 408 through a lot of bearing blocks 405 and 406. Sprocket 403 vehicle 404 coupled with the driven sprocket 402 attached to the outer surface of the first housing 401, through which the first housing 401 is rotated in response to operation of the driving means 404. The end of the first housing 401 corresponds to the output part of the casing 301 pumping unit 300, and therefore the molten polypropylene discharged from the pump portion 300, flows into the first housing 401. In the first case 401, the melt temperature of the polypropylene is modified to reflect the location (i.e. the Central part and the outer part of the inner space of the first building). However, since the molten polypropylene is stirred by the rotary movement of the first housing 401, the temperature of the entire molten polypropylene is maintained constant. Here, as a new melt polypropylene serves forcibly and continuously pumping part 400, the molten polypropylene rotates and moves at the same time.

Grinding part 400V consists of screw 410 connected to the output part of the first housing 401, the second housing 411, placed on the outer circumference of the screw 410, and covers the body 412 mounted on the outer circumference of the second housing 411 for forming a sealed PR is miucca between the second housing 411 and covering the housing 412. Screw 410 is cylindrical part having a spiral with a specific depth is formed on the outer surface on its circumference, and the period of the spiral shape is formed between the screw 410 and the second housing 411 and extends along the entire length of the screw 410. Therefore, the molten polypropylene discharged from the first housing 401 rotating parts 400A high pressure moves along the spiral gap forms between the screw 410 and the second housing 411 and is discharged from the grinding part 400V.

Meanwhile heat-transfer oil flows into the gap formed between the second housing 411 and covering the housing 412. That is, the inlet A, which serves the oil coolant, formed on one side of the covering body 412, outlet V through which heat-transfer oil is discharged, is formed on the other side of the covering body 412. Heat-transfer oil, which is injected into the gap between the second housing 411 and the frame body 412 through the inlet A, contact directly with the surface of the second housing 411 to adjust the melt temperature of the polypropylene, which flows in the second housing 411. Oil coolant, which flows between the second housing 411 and the frame body 412 to adjust the temperature of Rapla is and polypropylene, discharged through the outlet B. The processes of flow, temperature adjustment and unloading occur at the same time, helping to bring the melt temperature of the polypropylene, which flows between the spiral shape between the second housing 411 and the screw 410, to a predetermined temperature.

On the rear end of the homogenizing part 400, that is, the output of the second housing 411 is homogenizing device 450 for grinding and homogenizing the mixture paged melt polypropylene and a nucleating agent.

Figa and figv represent the views of the front rotary plate 451 and the fixed plate 452 comprising homogenizing device 450, respectively. Rotating plate 451 and the fixing plate 452 are the same shape and are mounted in such a state that they are in contact with each other under the condition that the rotating plate 451 is mounted for rotation.

Many holes A formed radially on a rotating plate 451, each hole A is oblique towards the center of the rotating plate 451. Many round holes A formed on the fixed plate 452.

The molten polypropylene discharged from the second cylinder 411, acts on the rotating plate 451, which rotates and passes through each of the opening A, formed on the rotating plate 451. At this point, the molten polypropylene cut edge of each hole A, thus all molten polypropylene is homogeneous ground. Chopped melt polypropylene pounded rotating plate 451, which rotates in the gap between the rotating plate 451 and the fixed plate 452 and is discharged through the holes A fixed plate 452.

That is, Spunbond part 500

The molten polypropylene temperature-controlled, leaving the homogenizing part 400, served in the spunbond part 500, to obtain a granulated foam.

Fig.7 is a view in plan showing the structure of spunbond parts shown in figure 1, and Fig is a view in section, taken along the line b-b In Fig.7 and Fig.9 is a view in section, taken along the line C-C in Fig. Spunbond part 500 is divided into discharging portion 500A, cutting edge 500V and the driving means 500C.

Disposable portion 500A comprises directing obstacles 501 in the form of a hollow cylinder and cylinder 502, located outside the guide barriers 501. On the outer circumference of the guide barriers 501 formed many cavities A in the longitudinal direction of the guide barriers 501. The molten polypropylene, leaving the homogenizing part 400, flows into each cavity A. Sets the through holes A formed on sections of the cylinder 502, consistent with the corresponding cavities A.

The cutting part 500V consists of a base plate 506, located on the back side of the disposable part 500A, and the cutting part 503, are attached to the base plate 506. The cutting part 503 is placed with the possibility of movement on the outer side of the cylinder 502 and has multiple through holes A formed at positions corresponding to the multiple through holes A cylinder 502, as shown in figure 9. As shown in the figures, the diameter of the through holes H formed on the cylinder 502 is less than the diameter of the through holes H formed on the cutting part 503. At the initial position of each through hole A cylinder 502 is located in the Central part of the corresponding through hole A cutting part 503.

Meanwhile, many grooves B formed on the outer circumference of the cylinder 502 in the longitudinal direction, and reciprocating movement of the rod 505 is placed in the grooves B, respectively. The cutting part 503 is attached to the reciprocating movement of the rods 505 clamping device, such as a bolt, thereby cutting the part 503 is driven in a reciprocating movement on the outer surface of the cylinder 502 reciprocating motion of the rod 505, which returns the but progressive moves along the groove V cylinder 502.

The driving means 500C spunbond part 500 comprises an eccentric Cam 511, which is driven by a motor 510, crank 512, which is connected with a Cam 511 and rotates in response to rotation of the Cam 511, and converts and transmits energy devices 513 connected to the crank 512, for converting the rotational motion of the crank 512 in linear motion and transmitting the linear movement of the support plate 506.

As soon as the Cam 511 is driven into rotation by the motor 510, the rotational movement of the crank 512 is converted into linear motion device 513 for conversion and transmission of energy and then transmitted to the base plate 506, which are attached to the ends of the cores 505, reciprocating movement. Thus, the cutting part 503 reciprocating moves along the outer circumference of the cylinder 502.

Meanwhile, melt polypropylene, leaving the homogenizing part 400, forcibly injected under pressure into a multitude of cavities A formed on the guide barrier 501, and then extend through the through holes A cylinder 502. At that time, when each through hole A cylinder 502 is consistent with each through hole A cutting part 503 when the reciprocating motion of the cutting part 503 under dvizhuschegosya 510, the molten polypropylene passes through the through hole A and A and then extends to the outer side of the cutting part 503 with a specific length. Then, when the through holes A cylinder 502 is released from a condition of alignment with the through holes A cutting part 503 when moving the cutting part 503, advanced melt polypropylene cut edges of the through holes A cutting part 503. Here, the size (length) of shredded foam is determined by the speed of movement of the cutting parts 503.

Thus, after the expansion of the molten polypropylene through the through holes A cylinder 502 and cutting the cutting part 503 are formed of foamed granules. The diameter of each through hole A cylinder 502 is equal to 0.7 mm, and the degree of expansion is equal to approximately 5 times the diameter of the through hole. In addition, the cutting part 503 performs a reciprocating motion at a speed of 600 revolutions per minute.

The molten polypropylene, moved from the grinding part 400 is subjected to a pressure of 120 kgf/cm²in spunbond part. If the molten polypropylene in filero has access directly into the atmosphere, most of the pins have open cells. In order to prevent the formation of open cells, in this invention, on the outer side of the spunbond parts installed decompress the traditional fixture.

7 shows an example of a decompression device that is installed on spunbond part. Decompression device 600 serves as the shell 601 to isolate the discharge portion 500A and the cutting part 500V spunbond part 500 from the outside (atmosphere). It should be clear that the shape of the shell 601 is not limited. The inlet 602, through which the introduced air is formed on one side of the shell 601, the output hole 603, through which the air is released, formed on the other side of the casing 601.

Air temperature, served in the shell 601 is equal to room temperature or below and can be maintained cooling devices (not shown). Moreover, needless to say that in order to properly support the pressure in the shell 601 (for example, of 0.8 kgf/cm²), the amount of air supplied to the shell 601 should be adjusted by a pump (not shown). Meanwhile, the hole 603 may be connected to a storage device for storing the obtained foamed granules together with manufactured air.

The temperature in the cylinder 502, forming a spunbond part 500, very high, and therefore the temperature of the cylinder 502 should be duly supported. For this purpose, the present invention uses a cooling device 700 with an oil carrier, which is mounted n the spunbond part.

Figa is a side view showing the cylinder spunbond part on which is mounted a cooling device, and FIGU is a front view figa. Shell 601 decompression device 600 depicted in Fig.7, for the sake of convenience, are not shown.

The cooling device 700 used in this invention contains a supply pipe 701-ring type which is placed on the front of the cylinder 502 and through which serves the oil coolant from an external source, multiple flow tubes 702, connected with the supply pipe 701 to its input end A and installed in the cylinder 502, and the discharge tube 703, located on the front of the cylinder 502 and is connected with the output end V flow tube 702.

Tube 701 ring type for supplying heat transfer oil, placed on the front of the cylinder 502, connected at one end with a device for forced flow (not shown), such as the pump, so the oil coolant serves in the supply tube at a constant pressure. Heat-transfer oil is forcibly injected into the set of flow tubes 702 via the input ends A flow tubes 702, connected with the supply pipe 701.

Many flow tubes 702, located at regular intervals along the whole outer circumference of the cylinder 502, passing the along the length of the cylinder 502, and each input end A and each output end V flow tubes 702 opened for access on the front end of the cylinder 502. Therefore, heat-transfer oil supplied through each input end A of the feeding tube 701 to supply heat transfer oil flows through the flow tube 702 along the entire length of the cylinder 502 (i.e. after heat exchange) and then discharged through each output end B.

Tube 703 ring type for discharging heat transfer oil, placed on the front of the cylinder 502, connected at one end with a reservoir for storing heat transfer oil (not shown). Thus, the oil coolant after heat exchange with the cylinder 502, flowing through the flow tubes 702, flows into the discharge tube 703 for heat transfer oil through the output end B and then sent to a storage tank for heat transfer oil.

As described above, during the flow through the feeding tube 701 for heat transfer oil, the flow tube 702, installed in the cylinder 702, and the discharge tube 703 for heat transfer oil, there is a heat exchange between the oil coolant and the cylinder 502, so the cylinder can be maintained at a constant temperature suitable for the production of foams.

Meanwhile, the supply pipe 701 to supply maslenok the coolant flowing in the tube 702 and the discharge tube 703, in which heat-transfer oil flows from the flow tubes 702, have an annular shape, so that the heat-transfer oil at the same time served and take from the flowing tubing 702 mounted on the circumference of the cylinder 502, the section which is circular in shape. However, the shape of the supply tube 701 and the discharge tube 703 is not limited to the ring, and they may have different shapes, such as polygonal shape.

Now the invention will be described in more detail in the following examples. However, it should be understood that the following examples are provided to illustrate various additional aspects of the present invention, but not intended to limit the scope of the invention in any aspect.

Example 1

In order to obtain granules of foamed seamless polypropylene according to this invention modifies the tandem extruder having a first extruder with an inner diameter of 65 mm and a second extruder with an inner diameter of 900 mm gear pump and spunbond part connected in series with the rear end of the second extruder. Homogenizing device, as shown in fig.z, set at the position where the melt is discharged from the gear pump, the compression device to provide outside nozzles. The through-hole nozzles have a diameter of 0.7 mm and the pressure in filereadarray at 0.5 kgf/cm ². The rotation speed of the first extruder set 24 Rev. in min and the rotation speed of the second extruder set of 9 Rev. in minutes

40 kg statistical copolymer RP2400 (polypropylene - 3 wt.% ethylene, a melt index of 0.25, melting point 138°C), commercially obtained from Yuhwa Korea Petrochemical Ind. Co., Ltd, and 800 g of sodium carbonate, commercially obtained from Keum Yang Co., Ltd., served in the extruder through the respective hoppers. 300 g of paraffin wax Ml, commercially obtained from Leochemical Co., Ltd (Kimhae, Korea), served in the third temperature zone of the first extruder. 13 kg LPG served at a fourth temperature zone of the extruder by using a metering pump. The temperature conditions set for the extruder to a homogenizing device, shown in table 1, and LD each temperature zone equal to 360 mm

Example 2

Temperature conditions in the device such as described in table 2 and granulated foam receive, using the same procedure and materials as in example 1.

Example 3

Temperature conditions in the device such as described in table 3, and foamed granules are obtained using the same procedure and materials as in example 1.

Example 4

Temperature conditions in the device such as described in table 4, and foamed granules are obtained using the same procedure and materials as in example 1.

Example 5

Temperature conditions in the device such as described in table 5, and foamed granules are obtained using the same procedure and materials as in example 1.

Example 6

Temperature conditions in the device such as described in table 6, and foamed granules are obtained using the same procedure and materials as in example 1.

Example 7

Temperature conditions in the device such as described in table 7, and foamed granules are obtained using the same procedure and materials as in example 1.

Comparative example 1

Foamed granules are obtained using the same procedure and materials as in example 1 and setting the temperature the business conditions in the device, as described in table 1, except that a homogenizing device is not working. Homogenizing device support at a temperature of 130°but does not enable. Therefore, the melt from the gear pump passes through the temperature zone 130°without homogenization for introduction into the Spinneret.

Comparative example 2

Foamed granules are obtained using the same procedure and materials as in example 1 and setting the temperature conditions in the device as described in table 1, except that the first temperature of the first zone of the extruder set 146°C.

Comparative example 3

Foamed granules are obtained using the same procedure and materials as in example 1 and setting the temperature conditions in the device as described in table 1, except that the second temperature zone of the first extruder set 173°C.

Comparative example 4

Foamed granules are obtained using the same procedure and materials as in example 1 and setting the temperature conditions in the device as described in table 1, except that the third temperature zone of the first extruder set 173°C.

Comparative example 5

Foamed granules are obtained using the same procedure and materials as in example 1 and setting the temperature conditions in the device, as described in table 1, except that the fourth temperature zone of the first extruder set 226°C.

Comparative example 6

Foamed granules are obtained using the same procedure and materials as in example 1 and setting the temperature conditions in the device as described in table 1, except that for the fifth temperature zone of the first extruder set 205°C.

Comparative example 7

Foamed granules are obtained using the same procedure and materials as in example 1 and setting the temperature conditions in the device as described in table 1, except that the sixth temperature zone of the first extruder set 187°C.

Comparative example 8

Foamed granules are obtained using the same procedure and materials as in example 1 and setting the temperature conditions in the device as described in table 1, except that the guide details set 256°C.

Comparative example 9

Foamed granules foam receive, using the same procedure and materials as in example 1 and setting the temperature conditions in the device as described in table 1, except that the first temperature zone of the second extruder set 174°C.

Comparative example 10

Foamed granules are obtained using the same procedure and materials as in example 1 and setting the temperature conditions in the device as described in table 1, except that the second temperature zone of the second extruder set 153°C.

Comparative example 11

Foamed granules are obtained using the same procedure and materials as in example 1 and setting the temperature conditions in the device as described in table 1, except that the third temperature zone of the second extruder set 148°C.

Comparative example 12

Foamed granules are obtained using the same procedure and materials as in example 1 and setting the temperature conditions in the device as described in table 1, except that the fourth temperature zone of the second extruder set 142°C.

Comparative example 13

Foamed granules are obtained using the same procedure and materials as in example 1 and setting the temperature conditions in the device as described in table 1, except that for the fifth temperature zone of the second extruder set 143°C.

Comparative example 14

Foamed granules are obtained using the same procedure and materials as in example 1 and setting the temperature of the services is via the device, as described in table 1, except that the sixth temperature zone of the second extruder set 138°C.

Comparative example 15

Foamed granules are obtained using the same procedure and materials as in example 1 and setting the temperature conditions in the device as described in table 1, except that the gear pump set 141°C.

Comparative example 16

Foamed granules are obtained using the same procedure and materials as in example 1 and setting the temperature conditions in the device as described in table 1, except that a homogenizing device set 131°C.

Experimental example 1

For expanded granules obtained in example 1 and example 2, measured with DSC (differential scanning calorimeter, 10°C/min to 200°, 50 CC/min to purge N2) temperature phase transition in accordance with the test method KSM3050-2001. The results are shown at 11 and Fig. As shown in the DSC curves 11 and Fig, the foam of example 1 and example 2 have a melting temperature 137,62°and 128,38°respectively, which are below the melting point of 138°With a statistical copolymer (RP2400 (a statistical copolymer of polypropylene-polyethylene(3%)), used as starting material. Stat is the statistical copolymer RP2400 used as a control during DSC measurements the phase transition temperature. The results are shown in Fig.

Experimental example 2

Foamed granules of example 1 and RP2400 (a statistical copolymer of polypropylene-polyethylene(3%)as the control is subjected to elementary analysis. The analysis is carried out using an elemental analyzer CE EA-1110. The results are shown in table 8 below.

N.D. means "not detectable". The detection limit of N equal to 0.1%.

Experimental example 3

Foamed granules of example 1 and RP2400 (a statistical copolymer of polypropylene-polyethylene(3%)as the control subject to the analysis FT-IR. The analysis is performed using FT-IR spectrophotometer, Bio-Rad Digilab FTS-165. The results are shown in Fig and pig respectively. According to the results, it is noted that the expanded granules obtained in example 1, and the statistical copolymer RP2400 have a major com is ANENT polypropylene.

Experimental example 4

The content of open cell foamed pellets obtained in examples and comparative examples was measured according to the procedure described in ASTM D 2856-70. The results are shown in table 9 below.

Experimental example 5

Other physical properties of the foams obtained in example 1 was measured according to the traditional method. The results are shown in table 10 below.

Experimental example 6

Foamed granules obtained in example 1 is formed by using a device for forming 500GF 4 produced Daekong Machinery Co., Ltd., with pressure molding to 2.5 kgf/cm²(temperature is about 138° (C)to obtain a good molded product. The production of such molded products confirmed that the granules foam according to this invention melt at a temperature of 138°With sticking to each other, which leads to the formation Nera is yameogo solid connection between the granules foam.

Experimental example 7

Foamed granules obtained in example 2 is formed by using a device for forming 500GF 4 produced Daekong Machinery Co., Ltd., with pressure molding to 2.4 kgf/cm²(temperature of about 132° (C)to obtain a good molded product. The production of such molded products confirmed that the granules foam according to this invention melt at a temperature of 132°With sticking to each other, which leads to the formation of permanent connection between the granules foam.

From the above description it is clear that this invention may be embodied in other forms, not deviating from the essence and not allowing exceptions characteristics of the present invention. Given this, it should be understood that the examples and experimental examples described above are only for example, but not as a limitation. This should not be interpreted so that all modifications and changes of the meaning and scope of the attached claims with regard equivalents, are intended for inclusion in the scope of this invention.

Granules of foamed seamless polypropylene according to this invention have a closed cell content of 80% or more and a melting point of from 125 to 140°so that the expanded granules according to the invention is very useful from the point of view formovania regeneration.

1. A method of producing granules of foamed seamless polypropylene having a melting point of from 125 to 140° containing stages:

(a) extruding seamless polypropylene statistical copolymer having a melting point of 138 to 140° and containing a nucleating agent and a blowing agent through a tandem extruder, which consists of the first extruder, is divided into the first temperature zone in which the set temperature from 147 to 153° With the second temperature zone in which the set temperature from 167 to 172° With, a third temperature zone, in which the set temperature of from 168 to 172° C, the fourth temperature zone in which set the temperature range from 218 to 225° C, fifth temperature zone in which the set temperature from 197 to 203° and the sixth temperature zone in which the set temperature from 188 to 193° C, the second extruder is divided into the first temperature zone in which the set temperature from 167 to 173° With the second temperature zone in which the set temperature from 147 to 152° With, a third temperature zone, in which the set temperature of 142° 147° C, the fourth temperature zone in which the set temperature from 137 to 141° C, fifth temperature zone to the second set temperature from 137 to 142° With, and the sixth temperature zone in which the set temperature from 132 to 137°and connecting the first extruder and the second extruder guide part in which the set temperature of from 248 to 255°C;

(b) the implementation of the forced flow of extrudable material by pumping the pump at a temperature of from 125 to 140° C;

(C) homogenizing extrudable material at a temperature of from 120 to 130° C;

(d) expansion of the homogenized material through a Spinneret and

(e) cutting the expanded material withobtaining a granulated foam.

2. The method according to claim 1, characterized in that the granules of foamed seamless polypropylene have 80% or more closed cells.

3. The method according to claim 1 or 2, characterized in that thegranules of foamed seamless polypropylene have a melting point of from 125 to 130° C.

4. Pellets of the resin foamed seamless polypropylene obtained by the method according to claim 1.

5. Device for producing granules from seamless foamed polypropylene having a melting point of from 125 to 140° made in the form of a tandem extruder containing the first extruder, is attached to the second extruder, pump, attached to the second extruder, homogenizing the part attached to the pumping part, and spunbond part, prisoedineniu to the homogenizing part, while the first and second extruders include a cylindrical housing in which is mounted auger for rotation, driving means located on the end of the cylinder, for rotating the auger and many cooling devices and heating devices located on the outer circumference of the cylinder for adjusting the melt temperature of the polypropylene in each cylinder, the cylinder of the first extruder has formed on its end portion and is consistent with the driving means inputs to supply the source of polypropylene and a nucleating agent, inputs for feed additives and a blowing agent, formed, respectively, in its middle part, and formed on the other end part of the output for feeding molten polypropylene, discharged from the cylinder of the first extruder, a second extruder through the guide part, pump part includes a housing in the inner space of which is to force a current supplied to it melt polypropylene, discharged from the second cylinder of the extruder, are rotatably and engagement with each other, a pair of gears associated with the driving means; homogenizing part contains for receiving molten polypropylene unloaded from the pump casing portion, the first cylindrical body with the possibility of the spine rotation by the driving means, connected with the output end of the first cylindrical body screw on the outer circumference of which is placed the second cylindrical body; on the outer circumference of the second cylindrical body is mounted covering the body with the formation of the airtight gap to control the melt temperature of the polypropylene in the second cylindrical housing through a heat transfer oil, and for grinding molten polypropylene at the rear end of the second body has a homogenizing device, between the auger and the second housing along the entire length of the screw is formed of a spiral gap for flow of molten polypropylene discharged from the first housing through a homogenizing device in spunbond part, which is designed for cutting expanded granules to the preset sizes and is from the unloading part, the cutting part and the driving means.

6. The device under item 5, wherein each of the cooling devices located on the cylinder of the extruder, a shell for flow supplied from the outside of the cooling water and the temperature of the melt of the polypropylene in the corresponding cylinder of the extruder, and each of the heating devices mounted between the two shells is a heater, to the m set the heating coil.

7. The device according to claim 5, characterized in that the cylinder of the first extruder is divided into six temperature zones, in accordance with the temperature of the molten polypropylene supplied to the cylinder to control the temperature of each zone by means of cooling and heating devices mounted on the outer circumference of the cylinder, the temperature of the molten polypropylene in the first temperature zone 147 - 153°With, in the second temperature zone 167 - 172°With, in the third temperature zone 168 -172°and the fourth temperature zone 218 - 225°With, in the fifth temperature zone 197 - 203°and the sixth temperature zone 188 - 193°C.

8. The device under item 5 or 7, characterized in that the inputs for submissionpolypropylene and a nucleating agent are located in the first temperature zone of the cylinder of the first extruder, the input additives constituting the antistatic agent is in the third temperature zone and the entrance to a blowing agent in the fourth temperature zone.

9. The device p. 8, characterized in that the input into the cylinder of the first extruder, a blowing agent, representing the CO₂connected to the feeder WITH₂containing a reservoir for storage of CO₂the section for evaporation and freezing of CO₂associated with the tank, the stabilizing section is Yu for the conversion of CO ₂supplied from the section for evaporation and freezing, in pairs, and memory section for storing CO₂supplied from the stabilizing section for feeding CO₂in the first cylinder of the first extruder.

10. The device under item 5, characterized in that the second cylinder of the extruder is divided into six temperature zones, in accordance with the temperature of the molten polypropylene supplied to the cylinder to control the temperature of each zone by means of cooling and heating devices mounted on the outer circumference of the cylinder, the temperature of the molten polypropylene in the first temperature zone 167 - 173°With, in the second temperature zone 147 - 152°With, in the third temperature zone 142 - 147°and the fourth temperature zone 137 - 141°With, in the fifth temperature zone 137 - 142°and the sixth temperature zone 132 - 137°C.

11. The device under item 5, characterized in that the two gears are located in the inner space of the pump casing part made with the possibility of rotation in opposite directions relative to the center of the internal space for the forced relocation of molten polypropylene to the next position in the process.

12. The device under item 5, characterized in that the first cylindrical body homogenizing part of the implementation of the Yong rotatably support plates through a set of bearing blocks, this sprocket driving means connected with the driven sprocket mounted on the outer surface circumference of the first housing for rotation of the first housing in response to operation of the vehicle.

13. The device under item 5, wherein the homogenizing device homogenizing part consists of a rotating plate mounted for rotation, and the locking plate is in contact with the rotating plate when the rotating plate has many holes arranged radially, and the fixing plate has many round holes for cutting edges of each hole of the rotating plate supplied molten polypropylene with subsequent rubbing of the rotating plate of chopped melt polypropylene between the rotating plate and the locking plate.

14. The device under item 5, characterized in that the unloading part of the spunbond part consists of a hollow guide barriers and cylinder located on the outside of the guide barriers, and guide barrier has many cavities formed on its outer circumference in the longitudinal direction of the guide barriers for feeding molten polypropylene, leaving the homogenizing part, in each cavity, with parts of the cylinder formed mnozhestvennyh holes, which are consistent with the respective cavities, the cutting part includes a support plate placed on the rear side of the discharge portion to which is attached a cutting parts that are located with the possibility of movement on the outside of the cylinder, with each cutting part has many through holes that are formed at positions that are consistent with many through holes of the cylinder, respectively, with the driving means include Cam, which is made to rotate by a motor, a crank connected with the eccentric for rotation in response to rotation of the Cam, and devices that convert and transmit energy, connected to the crank for converting the rotational movement of the crank into a linear movement and transmitting the linear movement of the support plate is attached to the cutting part, thereby each cutting part is made with the possibility of reciprocating motion along the outer circumference of the cylinder by the driving meansfor cutting the edges of the through holes of the cutting part of the foam passing through each through hole of the cylinder of expanded polypropylene.

15. The device according to p. 14, characterized in that the diameter of each through hole formed on the cylinder, IU is the more, than the diameter of each through hole of the cutting parts, each through hole of the cylinder is placed on the Central part consistent with him through hole of the cutting parts in the initial position.

16. The device according to p. 14, characterized in that the cylinder spunbond part has many grooves, which are formed on its outer circumference in the longitudinal direction, reciprocating rods, the ends of which are attached to the base plate and mounted for movement in the grooves, respectively, each cutting piece attached fixture to the corresponding terminal with the possibility of reciprocating movement on the outer circumference of the cylinder by means of a corresponding rod, which is driven in reciprocating motion along each of the grooves in the cylinder.

17. The device according to 14, wherein the spunbond part further comprises a decompression device to prevent rapid changes in temperature and pressure during the foaming and extrusion in the form of a shell, which is made in the ability to isolate the discharge part and the cutting part of the spunbond part from the outside (atmosphere), while the shell has an inlet for entry of air, which is located on one side of the shell, and RA is put on the other side of the casing outlet, able to release the air.

18. The device according to 14, wherein the spunbond part further comprises a cooling device for cooling the cylinder spunbond part containing a supply tube for supplying heat transfer oil from an external source, placed on the front of the cylinder, a set of flow tubes installed in the cylinder along the entire length of the cylinder and having input ends connected to the supply tube, discharge tube, located on the front of the cylinder and connected with the output ends of the flow tube, for receiving the liquid coolant after heat exchange with the cylinder.