CN113774505B - Polypropylene fiber, preparation method and sweeping brush - Google Patents

Abstract

The invention relates to a polypropylene fiber, which comprises the following components: 150 parts of polypropylene; 5-20 parts of toughening agent; 5-30 parts of filler; 0.5-3 parts of nucleating agent; 1-10 parts of internal lubricant; 0.5-5 parts of external lubricant.

Description

A kind of polypropylene fiber and preparation method and brush

technical field

The invention belongs to the field of polymer materials, and in particular relates to a polypropylene fiber, a preparation method and a brush.

Background technique

The sweeping brush is the cleaning and dust collection device of the sanitation vehicle. It has the functions of powerfully cleaning and removing the sticky matter on the ground, disturbing the garbage and sending it to the suction port with kinetic energy, picking up omissions and improving the operation ability. .

At present, the brush filaments of road sweeping brushes and snow sweeping brushes are mainly made of polypropylene, which is widely used because of its low cost and excellent processing performance. However, polypropylene has disadvantages such as poor wear resistance and easy splitting and fracture at low temperatures, which lead to problems such as limited cleaning environment and short service life. Therefore, there is a need to improve the performance of polypropylene brush filaments.

Contents of the invention

In view of the above problems, the present invention provides a novel polypropylene fiber having improved abrasion resistance, lower embrittlement temperature and higher crystallinity. The polypropylene fibers are suitable for use as sweeping filaments.

In some aspects, the present disclosure provides a polypropylene fiber comprising the following components:

150 parts of polypropylene;

5-20 parts of toughening agent (for example, 5-10 parts, 10-15 parts);

5-30 parts of filler (for example, 10-15 parts, 15-20 parts, 20-25 parts);

0.5-3 parts of nucleating agent (for example, 1-1.5 parts, 2.5-2 parts, 2-2.5 parts);

1-10 parts of internal lubricant (for example, 2-4 parts, 3-5 parts, 4-6 parts, 5-7 parts, 6-8 parts, 7-9 parts); and

0.5-5 parts of external lubricant (for example, 1-2 parts, 2-3 parts, 3-4 parts).

In some embodiments, the polypropylene homopolymer is Taiwan Yongjia 1124 polypropylene.

In some embodiments, the properties of the polypropylene homopolymer are as follows: the tensile strength is 38-42 MPa, the nominal value of the tensile elastic modulus is 210-230 MPa, and the Charpy notched impact strength is 2.8-3.2 kg cm/cm ( According to ASTM D-256), the melt mass flow rate is 14-16g/10min, and the test conditions are: temperature 230°C, load 2.16kg.

In some embodiments, the polypropylene copolymer is Taiwan Yongjia 3015 polypropylene.

In some embodiments, the properties of the polypropylene donor polymer are as follows: the tensile strength is 26-30 MPa, the nominal value of the tensile elastic modulus is 110-120 MPa, and the Charpy notched impact strength is 40-50 kg cm/cm (according to ASTM D-256), the melt mass flow rate is 2.8-2.2g/10min, and the test conditions are: temperature 230°C, load 2.16kg.

In some embodiments, the polypropylene fiber also includes the following components:

0.5 to 1 part of antioxidant (for example, 1 to 1.5 parts, 2.5 to 2 parts, 2 to 2.5 parts); and/or

0.5-1 part of ultraviolet absorber (for example, 0.7-0.9 part).

In some embodiments, based on the total weight of polypropylene as 100%, the polypropylene comprises:

Polypropylene homopolymer 60-70% (for example, 66%-67%);

30-40% (for example, 33%-34%) of polypropylene copolymer.

In some embodiments, the toughening agent is selected from one or more of ethylene-vinyl acetate copolymer (EVA), polyethylene octene co-elastomer (POE), and ethylene-propylene-diene rubber (EPDM).

In some embodiments, the filler is selected from one or more of calcium carbonate, calcium sulfate whiskers, and nano-silica.

In some embodiments, the filler is a modified filler, and the modification method is selected from modification with a silane coupling agent, modification with an aluminate coupling agent, or modification with a titanate coupling agent.

In some embodiments, the nucleating agent is selected from one or more of cyclohexyl phthalate and cyclohexanamide naphthalene dicarboxylate.

In some embodiments, the internal lubricant is calcium stearate and the external lubricant is paraffin.

In some embodiments, the antioxidant is selected from one or more of antioxidant 1010, antioxidant 626, and antioxidant 168.

In some embodiments, the ultraviolet absorber is selected from one or more of ultraviolet absorber UV531 and ultraviolet absorber UV770.

In some aspects, the present disclosure provides a method of preparing polypropylene fibers according to any one of the above, comprising:

a) mixing raw materials according to the composition formula of the polypropylene fiber;

b) adding the raw materials into the extruder, extruding from the extruder, drawing the fibers through the first drawing device, and heating the fibers in the first oven at a first heating temperature of 160°C to 200°C to obtain the first fibers;

c) the first fiber enters the second drawing device for drawing and stretching, the drawing ratio is 4:1-6:1, enters the second oven for heating, the second heating temperature is 100°C-150°C, and obtains the second fiber;

d) The second fiber enters the cooling water tank, the temperature of the cooling water is below 10°C, the cooled fiber is pulled and drawn by the third pulling device, and the drawing ratio is 1:1-1:1.25, and the third fiber is obtained.

In some embodiments, a shearing force applying device is further provided between the first oven and the second drawing device of the propylene fiber production system, and the shearing force applying device applies a shearing force to the fibers entering the second drawing device, The shearing force is selected from radial shearing force, circumferential shearing force or a combination thereof.

In some embodiments, the shearing force applying device includes: one or more of an ultrasonic vibration device, a rotary shearing device, and a plasma sputtering device.

In some embodiments, the shear force applying device is an ultrasonic vibrating device that vibrates the polypropylene fibers in a radial direction. The frequency of the vibration is, for example, 30 to 50 kHz, for example, 40 kHz. The amplitude of the vibration is, for example, 0.01 cm to 0.5 cm.

In some embodiments, a plasma sputtering device (eg, a carbon dioxide plasma sputtering device) radially sputters polypropylene fibers with a plasma (eg, _CO2 plasma). The plasma discharge voltage is, for example, 40V to 80V.

In some embodiments, the shearing force applying device is a rotary shearing device. The rotary shearing device applies a rotary shearing force (circumferential shearing force) to the polypropylene fiber, and the value of the shearing force is 5-15N, for example, 8-12N.

In some embodiments, a first cooling water tank is provided between the extruder and the first pulling device, and the temperature of the cooling water is 20-30° C. (for example, 25° C.).

In some embodiments, a second cooling water tank is further provided between the second oven and the third pulling device, and the temperature of the cooling water is below 10°C.

In some embodiments, the extruder sequentially includes the following six temperature zones in order from the feed end to the discharge end:

The first temperature zone: 165-175°C (for example, 170°C);

Second temperature zone: 180-190°C (eg 185°C);

The third temperature zone: 195～205°C (for example, 200°C);

The fourth temperature zone: 195-205°C (eg 200°C);

Fifth temperature zone: 205-215°C (eg 210°C);

Sixth temperature zone: 205-215°C (for example, 210°C).

In some embodiments, the polypropylene fibers have a diameter of 1-5 cm, such as 1.5-3.5 cm.

In some aspects, the present disclosure provides a brush, including brush filaments, and the material of the brush filaments is the polypropylene fiber described in any one of the above.

In the present invention, unless otherwise specified, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art. Moreover, the laboratory operation steps involved in this article are all routine steps widely used in the corresponding fields. Meanwhile, in order to better understand the present invention, definitions and explanations of relevant terms are provided below.

The term "polypropylene homopolymer" means a polymer polymerized from one monomer, propylene.

The term "polypropylene copolymer" means that the molecular chain structure contains other monomer molecules besides propylene monomer, such as ethylene and butene. The polypropylene copolymer may be a propylene ethylene copolymer or a propylene butene copolymer.

Beneficial effect

One or more embodiments of the present disclosure have one or more of the following beneficial effects:

a) The polypropylene homopolymer and polypropylene copolymer are blended to make the polypropylene fiber have both high strength and high toughness, so that the polypropylene fiber has good mechanical properties;

b) The formula contains a nucleating agent (cyclohexyl phthalate or cyclohexyl naphthalene dicarbamide, etc.) components, which can increase the crystallinity of polypropylene, optimize the β crystal ratio, and improve the wear resistance of polypropylene fibers;

c) The formula contains toughening agent components (incorporating EVA, POE or EPDM, etc.), which can improve the low temperature resistance of polypropylene fibers;

d) The formulation contains lubricants (paraffin, calcium stearate, etc.), which optimize the processing performance of polypropylene fibers, increase the surface finish of polypropylene fibers, and reduce the friction coefficient between polypropylene fibers and the ground;

e) In the preparation method, the hardness and rigidity of the polypropylene fiber are improved by adopting a three-stage stretching method, and the wear resistance of the polypropylene fiber is improved;

f) In the preparation method, the device that provides shear force for the polypropylene fiber optimizes the crystallinity of the polypropylene fiber in the direction perpendicular to the stretching direction, so that the polypropylene fiber crystallizes in two directions at the same time, which improves the work of the polypropylene fiber The problem of splitting and breaking.

Description of drawings

Figure 1 is a schematic diagram of a system for producing polypropylene fibers.

Figure 2 is a schematic view of a polypropylene fiber being treated by a shear force application device.

Fig. 3 is a schematic diagram of yet another polypropylene fiber being treated by a shear force applying device.

Detailed ways

Embodiments of the present invention will be described in detail below in conjunction with examples, but those skilled in the art will understand that the following examples are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Those who do not indicate specific conditions in the examples are carried out according to conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used were not indicated by the manufacturer, and they were all commercially available conventional products.

The raw materials used in the following examples are shown in the table below:

As shown in Figure 1, a system for preparing polypropylene fibers. As shown in the figure, in an embodiment of preparing polypropylene fibers, firstly, the raw materials for preparing polypropylene fibers are fed into the single-screw extruder 1, and the raw materials are melted in the single-screw extruder 1, and the molten resin is extruded The extruded head 2 is extruded, and the extruded material is cooled by the first cooling water tank 3, and then enters the first traction device 4, and the polypropylene fiber output by the first traction device 4 is heated by the first oven 5, and then enters the first Two traction devices 7, a shearing force applying device 6 is arranged before the entrance of the second traction device 7, and the fiber output by the second traction device 7 enters the second oven 8 for heating, and the heated fiber enters the second cooling water tank 9 for cooling, and The final fiber is drawn and stretched by the third drawing device 10, and the fiber output by the third drawing device 10 enters the cut-to-length device 11, and the polypropylene fiber product 12 is obtained after cutting to length.

Figure 2 is a schematic view of a polypropylene fiber being treated by a shear force application device. As shown in the figure, the shearing force applying device in this embodiment is a radial shearing force applying device 210 . The radial shearing force applying device 210 applies radial shearing force to the radial direction of the fiber 200, and the direction of the shearing force is shown by the arrow.

Fig. 3 is a schematic diagram of yet another polypropylene fiber being treated by a shear force applying device. As shown in the figure, the shearing force applying device in this embodiment is a circumferential shearing force applying device 220 . The circumferential shearing force applying device 220 applies circumferential radial shearing force (for example, rotational shearing force) to the circumferential direction of the fiber 200, and the direction of the shearing force is shown by the arrow.

The process steps for preparing polypropylene fibers are further described in detail below through specific examples.

Example 1

1) According to parts by weight, take 100 parts of polypropylene homopolymer, 50 parts of polypropylene copolymer, 5 parts of EPDM, 15 parts of modified calcium carbonate, 0.6 part of cyclohexanamide phthalate, 3 parts of calcium stearate, 1 part of paraffin, 0.5 part of antioxidant 1010, 0.5 part of antioxidant 168, 0.5 part of ultraviolet absorber UV531;

2) Mix the weighed raw materials evenly and add them to the single-screw extruder for extrusion. The temperature of each section from the first zone to the sixth zone of the extruder is set as: 170°C, 185°C, 200°C, 200°C, 210°C, 210°C;

3) After the material is filtered, measured and pressurized, the fiber is extruded from the die hole of the machine head;

4) After being cooled by the first cooling water tank, the extruded fiber enters the first traction device for uniform traction, and the traction speed is 10m/min;

5) After the brush filament passes through the first drawing device, it enters the first oven for heating, and the temperature of the oven is set at 180°C. The heated fiber enters the second drawing device for stretching, and the drawing ratio is 5:1;

6) A shearing force applying device (ultrasonic vibration device) is provided in front of the entrance of the second traction device, and its frequency is set to 40 kHz. The fiber after the second drawing device passes through the second oven, the temperature of the oven is set at 150°C, and reaches the third drawing device through the second cooling water tank, the water temperature of the second cooling water tank is 10°C, the third drawing device and the first drawing device The draw ratio of the second drawing device is 1.25:1, and the brush filaments finally pass through the cut-to-length cutting machine after the third drawing device, and are cut to the required size to obtain polypropylene fiber products (2.5 cm in diameter).

Example 2

1) According to parts by weight, weigh 100 parts of polypropylene homopolymer, 50 parts of polypropylene copolymer, 5 parts of EVA, 15 parts of modified calcium carbonate, 0.5 part of cyclohexanamide phthalate, 3 parts of calcium stearate, paraffin wax 1 part, 0.5 part of antioxidant 1010, 0.5 part of antioxidant 168, 0.5 part of ultraviolet absorber UV531;

2) Mix the weighed raw materials evenly and add them to the single-screw extruder for extrusion. The temperature of each section from the first zone to the sixth zone of the extruder is set as: 170°C, 185°C, 200°C, 200°C, 210°C, 210°C;

3) After the material is filtered, measured and pressurized, the fiber is extruded from the die hole of the machine head;

4) After being cooled by the first cooling water tank, the extruded fiber enters the first traction device for uniform traction, and the traction speed is 10m/min;

5) After the brush filament passes through the first drawing device, it enters the first oven for heating, and the temperature of the oven is set at 180°C. The heated fiber enters the second drawing device for stretching, and the drawing ratio is 5:1;

6) A shearing force applying device (rotary shearing device) is provided in front of the entrance of the second pulling device, which applies a rotational shearing force of 10N to the fibers in the circumferential direction perpendicular to the drawing direction of the brush filaments. The fiber after the second drawing device passes through the second oven, the temperature of the oven is set at 150°C, and reaches the third drawing device through the second cooling water tank, the water temperature of the second cooling water tank is 10°C, the third drawing device and the first drawing device The drawing ratio of the second drawing device is 1.25:1, and the fiber finally passes through the cut-to-length cutting machine after the third drawing device, and is cut to the required size to obtain a polypropylene fiber product (2.3 cm in diameter).

Example 3

1) According to parts by weight, weigh 100 parts of polypropylene homopolymer, 50 parts of polypropylene copolymer, 5 parts of EVA, 15 parts of modified calcium carbonate, 0.5 part of cyclohexanamide phthalate, 3 parts of calcium stearate, paraffin wax 1 part, 0.5 part of antioxidant 1010, 0.5 part of antioxidant 168, 0.5 part of ultraviolet absorber UV531;

2) Mix the weighed raw materials evenly and add them to the single-screw extruder for extrusion. The temperature of each section from the first zone to the sixth zone of the extruder is set as: 170°C, 185°C, 200°C, 200°C, 210°C, 210°C;

3) After the material is filtered, measured and pressurized, the fiber is extruded from the die hole of the machine head;

4) After being cooled by the first cooling water tank, the extruded fiber enters the first traction device for uniform traction, and the traction speed is 10m/min;

5) After passing through the first drawing device, the fiber enters the first oven for heating, and the temperature of the oven is set at 180°C, and the heated fiber enters the second drawing device for stretching, and the drawing ratio is 5:1;

6) Before the entrance of the second drawing device, a shearing force applying device (plasma generating device) is arranged, and this device gives the fiber continuous carbon dioxide plasma sputtering treatment perpendicular to the fiber drawing direction (radial direction). The fiber after the second drawing device passes through the second oven, the temperature of the oven is set at 150°C, and reaches the third drawing device through the second cooling water tank, the water temperature of the second cooling water tank is 10°C, the third drawing device and the first drawing device The drawing ratio of the second drawing device is 1.25:1, and the fiber finally passes through the cut-to-length cutting machine after the third drawing device, and is cut to the required size to obtain a polypropylene fiber product (2.5 cm in diameter).

Example 4

1) According to parts by weight, weigh 100 parts of polypropylene homopolymer, 50 parts of polypropylene copolymer, 5 parts of EVA, 15 parts of modified calcium carbonate, 0.5 part of cyclohexanamide phthalate, 3 parts of calcium stearate, paraffin wax 1 part, 0.5 part of antioxidant 1010, 0.5 part of antioxidant 168, 0.5 part of ultraviolet absorber UV531;

2) Mix the weighed raw materials evenly and add them to the single-screw extruder for extrusion. The temperature of each section from the first zone to the sixth zone of the extruder is set as: 170°C, 185°C, 200°C, 200°C, 210°C, 210°C;

3) After the material is filtered, measured and pressurized, the fiber is extruded from the die hole of the machine head;

4) The extruded fibers are cooled by the first cooling water tank (temperature 25°C), and then enter the first traction device for uniform traction, and the traction speed is 10m/min;

5) After the brush filament passes through the first drawing device, it enters the first oven for heating, and the temperature of the oven is set at 180°C. The heated fiber enters the second drawing device for stretching, and the drawing ratio is 5:1;

6) The fiber after the second drawing device passes through the second oven, the temperature of the oven is set at 150°C, and reaches the third drawing device through the second cooling water tank, the water temperature of the second cooling water tank is 10°C, and the third drawing device The drawing ratio with the second drawing device is 1.25:1, and the brush filament finally passes through the cut-to-length cutting machine after the third drawing device, and is cut to the required size to obtain a polypropylene fiber product (2.5 cm in diameter).

Comparative example 1

1) According to parts by weight, weigh 100 parts of polypropylene homopolymer, 0.5 part of antioxidant 1010, 0.5 part of antioxidant 168, and 0.5 part of ultraviolet absorber UV531;

2) Mix the weighed raw materials evenly and add them to the single-screw extruder for extrusion. The temperature of each section from the first zone to the sixth zone of the extruder is set as: 170°C, 185°C, 200°C, 200°C, 210°C, 210°C;

3) After the material is filtered, measured and pressurized, the fiber is extruded from the die hole of the machine head;

4) After being cooled by the first cooling water tank, the extruded fiber enters the first traction device for uniform traction, and the traction speed is 10m/min;

5) After passing through the first drawing device, the fiber enters the first oven for heating, and the temperature of the oven is set at 180°C, and the heated fiber enters the second drawing device for stretching, and the drawing ratio is 5:1;

6) The fiber after the second drawing device passes through the second oven, the temperature of the oven is set at 150°C, and reaches the third drawing device through the second cooling water tank, the water temperature of the second cooling water tank is 10°C, and the third drawing device The draw ratio with the second drawing device is 1.25:1, and the fiber finally passes through the cut-to-length machine after the third drawing device, and is cut to the required size to obtain a polypropylene fiber product (2.6 cm in diameter).

The fibers prepared in Examples 1-4 and Comparative Examples were tested as follows:

(1) Carry out wear test on the wear test bench;

(2) Determination of embrittlement temperature according to GB/T5740-2008;

(3) The crystallinity of the fiber was tested using a differential scanning calorimeter.

The results are shown in Table 1.

Table 1 embodiment and comparative example test value summary table

serial number Abrasion (g) Embrittlement temperature (°C) Crystallinity (%) Example 1 twenty three -42 38.5 Example 2 26 -45 40.3 Example 3 18 -50 39.8 Example 4 59 -32 34.7 Comparative example 1 120 -twenty three 32.6

It can be seen from the experimental data in Table 1 that:

Compared with Comparative Example 1, for the schemes of Examples 1 to 4, a) the blending of polypropylene homopolymer and polypropylene copolymer is used to make the polypropylene fiber have both high strength and high toughness, so that the polypropylene The fiber has good mechanical properties; b) adding cyclohexanamide phthalate nucleating agent component improves the crystallinity of polypropylene, optimizes the β crystal ratio, and improves the wear resistance of polypropylene fiber; c) adds Toughener components (EVA, EPDM, etc.) improve the low temperature resistance of polypropylene fibers; d) add lubricants (paraffin, calcium stearate, etc.) to optimize the processing performance of polypropylene fibers and increase the The smoothness of the surface reduces the coefficient of friction between the polypropylene fiber and the ground; e) the three-stage stretching method is used to improve the hardness and stiffness of the polypropylene fiber and improve the wear resistance of the polypropylene fiber.

Compared with Example 4, Examples 1 to 3 further adopted a device for providing shear force of polypropylene fibers, which optimized the crystallinity of polypropylene fibers perpendicular to the stretching direction, so that the polypropylene fibers could be stretched in two directions at the same time. Crystallization occurs, which improves the problem of splitting and breaking of polypropylene fibers during work.

In summary, the wear-resistant and low-temperature resistant polypropylene fiber obtained by the above method in the present invention has excellent low-temperature resistance and wear resistance, and is particularly suitable for use as brush filaments.

Although the specific implementation of the present invention has been described in detail, those skilled in the art will understand that: according to all the teachings that have been disclosed, various modifications and changes can be made to the details, and these changes are all within the protection scope of the present invention . The full scope of the invention is given by the appended claims and any equivalents thereof.

Claims (9)

1. A method of making polypropylene fibers comprising:

a) The raw materials are mixed according to the component formula of the polypropylene fiber, and the polypropylene fiber comprises the following components:

150 parts of polypropylene, wherein the polypropylene comprises, based on 100% of the total weight of the polypropylene: 60-70% of polypropylene homopolymer and 30-40% of polypropylene copolymer;

5-20 parts of toughening agent, wherein the toughening agent is selected from one or more of ethylene-vinyl acetate copolymer (EVA) and Ethylene Propylene Diene Monomer (EPDM);

5-30 parts of filler, wherein the filler is calcium carbonate;

0.5-3 parts of nucleating agent which is cyclohexane phthalic acid amide;

1-10 parts of an internal lubricant, wherein the internal lubricant is calcium stearate;

0.5-5 parts of external lubricant, wherein the external lubricant is paraffin;

0.5-1 part of an antioxidant, wherein the antioxidant is selected from one or more of an antioxidant 1010 and an antioxidant 168;

0.5-1 part of ultraviolet absorber, wherein the ultraviolet absorber is selected from one or more of ultraviolet absorber UV531 and ultraviolet absorber UV 770;

b) Providing a polypropylene fiber production system, wherein the production system comprises an extruder, a first traction device, a first oven, a second traction device, a second oven and a third traction device;

c) Adding raw materials into an extruder, extruding from the extruder, drawing by a first drawing device to form fibers, heating the fibers in a first oven at a first heating temperature of 160-200 ℃ to obtain first fibers;

d) The first fiber enters a second traction device for traction and stretching, the stretching ratio is 4:1-6:1, the first fiber enters a second oven for heating, the second heating temperature is 100-150 ℃, and the second fiber is obtained;

e) Drawing and stretching the second fiber by a third drawing device, wherein the drawing ratio is 1:1-1:1.25, and obtaining a third fiber;

wherein a shear force application device is further disposed between the first oven and the second traction device of the propylene fiber production system, the shear force application device applying a shear force to the fibers entering the second traction device, the shear force selected from the group consisting of radial shear force, circumferential shear force, or a combination thereof.

2. The method of claim 1, the shear force application device comprising: one or more of an ultrasonic vibration device, a rotary shearing device and a plasma generating device.

3. The method of claim 2, wherein the ultrasonic vibration device radially applies vibration to the fibers at a frequency of 30-50 kHz.

4. The method of claim 2, the rotary shearing device applying a circumferential shear force to the fibers of 5 to 15N.

5. The method according to claim 1, characterized by one or more of the following:

a first cooling water tank is arranged between the extruder and the first traction device, and the temperature of the cooling water is 20-30 ℃;

and a second cooling water tank is also arranged between the second oven and the third traction device, and the temperature of the cooling water is below 10 ℃.

6. The process according to claim 1, wherein the extruder comprises, in order from the feed end to the discharge end, the following six temperature zones,

first temperature zone: 165-175 ℃;

second temperature zone: 180-190 ℃;

third temperature zone: 195-205 ℃;

fourth temperature zone: 195-205 ℃;

fifth temperature zone: 205-215 ℃;

sixth temperature zone: 205-215 ℃.

7. The method of claim 1, wherein the filler is a modified filler, the modification method selected from the group consisting of silane coupling agent modification, aluminate coupling agent modification, and titanate coupling agent modification.

8. A polypropylene fiber obtainable by the process of any one of claims 1 to 7.

9. A broom comprising brush filaments, said brush filaments being made of the polypropylene fibers of claim 8.