Lightweight soft polypropylene foamed brush filament, and preparation method and application thereof

Abstract

The present application belongs to the technical field of polypropylene foaming modification, and provides a light and soft polypropylene foaming brush filament and a preparation method thereof.The light and soft polypropylene foaming brush filament is composed of the following components with the weight percentage: 70-90% of polypropylene, 5-25% of linear low-density polyethylene, 0.02-1% of dispersant, 0-5% of colorant, and 0.2-5% of foaming agent.The preparation method of the polypropylene foaming brush filament has the characteristics of simple production mode and high continuous production stability.The polypropylene foaming brush filament has the characteristics of small product diameter, light density, high specific strength, softness and good resilience, and is not easy to damage the surface of objects during use, and can be used for cleaning brushes, kitchen brushes, civilian brushes and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polypropylene foaming modification, and particularly relates to a light and soft polypropylene foaming brush filament as well as a preparation method and application thereof. BACKGROUND

[0002] The polypropylene brush filament (PP brush filament) has high hardness, is resistant to wear and chemicals, has low unit price, and is widely applied to road sweeping brushes, cleaning brushes, kitchen brushes, civilian brushes or industrial brushes, etc. However, due to the high hardness of the PP, the PP brush filament is used for a long time at a high smoothness interface, which can damage the smoothness of the surface of an object and cause the surface to be abraded or lose gloss.

[0003] In the article of Research Progress of Polypropylene Foaming Material by Yuan Chao of the State Intellectual Property Office Patent Examination Collaboration Center, Guangdong, it is pointed out that the traditional PP foaming process has poor performance, because the ordinary polypropylene has a soft long-chain macromolecular structure, high crystallinity and high crystallization tendency, and the viscosity rapidly decreases after reaching the melting point (low melt viscosity and insufficient melt strength), at this time, the foaming generates gas escape, the PP melt cannot wrap the bubbles, and then the cells collapse. The high melt strength polypropylene is prepared by industrial direct synthesis, crosslinking modification and blending modification and then foaming. The industrial direct synthesis method is expensive, the blending modification method obtains the high melt strength polypropylene by melt blending of polypropylene powder, pre-irradiation polypropylene powder, pre-irradiation vulcanized rubber powder, monomer additive and heat stabilizer, the product prepared by the method is difficult to maintain all the properties of the polypropylene, and the prepared product has poor performance.

[0004] At present, it is urgent to develop a preparation method of the PP foaming brush filament, reduce the density and hardness of the PP brush filament, and make the PP brush filament suitable for cleaning brushes, kitchen brushes and civilian brushes. SUMMARY

[0005] The embodiment of the application provides a light and soft polypropylene foaming brush filament, a preparation method and application thereof. The polypropylene foaming brush filament prepared by the application has the characteristics of small product diameter, light density, high specific strength, softness and good resilience, and is not easy to damage objects during use, and can be used for cleaning brushes, kitchen brushes, civilian brushes and the like.

[0006] The embodiment of the application is implemented as follows:

[0007] A light and soft polypropylene foaming brush filament is composed of the following components in percentage by weight: 70% to 90% polypropylene, 5% to 25% linear low-density polyethylene, 0.02% to 1% dispersing agent, 0% to 5% colorant and 0.2% to 5% foaming agent.

[0008] Preferably, the melt index of the polypropylene is 2-8 g / 10 min, and the test conditions are 230 DEG C and 2.16 Kg.

[0009] Preferably, the linear low density polyethylene (LLDPE) is used to increase the melt viscosity of the mixture.

[0010] Preferably, the dispersant is preferably a diffusion oil.

[0011] Preferably, the colorant is a color powder or a color master.

[0012] The foaming agent preferably has a fast gas release speed and a controllable gas generation rate; the residue after decomposition is non-toxic, colorless, odorless, does not affect the physical, chemical and mechanical properties of PP, and is chemically inert, does not affect the melting rate and solidification of PP; the residue after decomposition is compatible with PP and does not cause residue blooming or dialysis; and the decomposition temperature range of the foaming agent is consistent with the melting temperature range of polypropylene (PP).

[0013] Preferably, the foaming agent has a decomposition temperature of 160-220℃; the decomposition temperature is consistent with the melting temperature of polypropylene (PP).

[0014] Preferably, the foaming agent is preferably an AC foaming agent (azodicarbonamide).

[0015] The above method for preparing the light and soft polypropylene foamed brush filament comprises the following steps:

[0016] (1) 70%-90% polypropylene, 5%-25% linear low density polyethylene, 0.02%-1% dispersant, and 0%-5% colorant, 0.2%-5% foaming agent are added to a stirrer and stirred uniformly to form a mixture;

[0017] (2) The mixture obtained in step (1) is added to a single-screw extruder, extruded from a spinneret, cooled and shaped, stretched and shaped, and finally wound and cut to obtain a light and soft polypropylene foamed brush filament.

[0018] Preferably, the filter screen of the extruder in step (1) is selected from a plurality of different mesh size filter screens with a mesh size range of 60-400. The use of a plurality of different mesh size filter screens in the extruder avoids the entry of burnt material, external impurities or insufficiently plasticized resin into the head, affecting the foaming of the brush filament; at the same time, the appropriate mesh size and number of layers of the filter screen are conducive to stabilizing the pressure of the mixture melt before extrusion, and help to control the foaming amount and cell diameter of the brush filament.

[0019] In the preparation process, the extruder head temperature is one of the key factors determining the density and mechanical properties of the foamed filaments. A lower head temperature results in a thicker skin and better smoothness, but also a lower foaming rate and higher density. A higher head temperature reduces melt strength, making it easier for gas to escape from the head and foam on the surface. Subsequently, the foam cells collapse, affecting the surface quality of the filaments. Considering all the properties of the material, the extruder head temperature in step (1) is preferably set to 170-190℃.

[0020] During the process of dissolving the foaming agent to generate gas, in order to maintain the extruder barrel pressure within a suitable range, the speed of the extruder in step (1) is preferably 20-30 RPM, which can prevent bubbles from overflowing and is conducive to bubble nucleation. At this time, the extrudate expands rapidly after leaving the mold, and the foamed material is densely covered with a large number of tiny pores, resulting in high toughness and a smooth surface.

[0021] Preferably, in step (2), the extruder temperature is set to 170-230°C when extruding from the spinneret.

[0022] Preferably, the cooling and shaping process in step (2) uses a cooling and shaping temperature of 5-20℃.

[0023] Preferably, the stretching ratio of the monofilament in step (2) is 3-7 times.

[0024] Preferably, the shaping temperature in step (2) is 70-250℃.

[0025] The lightweight and soft polypropylene foamed bristles prepared in the above manner are used in cleaning brushes, kitchen brushes, and household brushes.

[0026] This invention successfully prepared a lightweight and soft polypropylene (PP) foamed brush filament by adjusting the process of producing polypropylene (PP) brush filaments, including adjusting the extruder head temperature, extruder speed, filter screen, and adding foaming agent. This brush filament is lightweight and soft, and is less likely to damage objects during use. It can be used for cleaning brushes, kitchen brushes, household brushes, etc. The polypropylene (PP) brush filaments prepared by this invention have higher resilience compared to untreated polypropylene (PP) brush filaments. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0028] Given that current polypropylene brush filaments lack sufficient softness and are prone to damaging object surfaces, this invention provides a lightweight and soft polypropylene foamed brush filament and its preparation method. By adjusting the composition and process of polypropylene foamed brush filaments (PP foamed brush filaments), this invention produces brush filaments that are lightweight and soft, less likely to damage objects during use, and suitable for cleaning brushes, kitchen brushes, household brushes, etc.

[0029] Example 1

[0030] This embodiment provides a method for preparing lightweight and soft polypropylene foamed brush filaments, including the following steps:

[0031] (1) Mix 85% polypropylene (PP), 13.5% linear low-density polyethylene (LLDPE), 0.05% dispersant, 0.45% colorant and 1% foaming agent evenly in a mixer;

[0032] (2) The mixture obtained in step (1) is added to a single screw extruder and extruded from the spinneret. After cooling, shaping, stretching, and shaping, it is finally wound and cut to obtain a lightweight and soft polypropylene foamed brush filament with a diameter of 0.45 mm.

[0033] In step (1), the melt index of polypropylene (PP) is 2-8 g / 10 min, and the test conditions are 230℃ and 2.16 kg.

[0034] The foaming agent mentioned in step (1) is an AC foaming agent (azodicarbonamide) with a decomposition temperature of 160-190℃.

[0035] The filter screen of the extruder mentioned in step (1) is a multi-layer filter screen with different mesh sizes ranging from 60 to 400.

[0036] The extruder head temperature in step (1) is set to 180°C.

[0037] The speed of the extruder in step (1) is preferably 25 RPM.

[0038] When extruding from the spinneret as described in step (2), the extruder temperature is set to 170-210℃. Conventional extruders are divided into several sections such as melting, compression, and metering. Depending on the material, the temperature of each section is set between 170-210℃.

[0039] The cooling and shaping process described in step (2) uses a cooling and shaping temperature of 12°C.

[0040] The stretching ratio of the monofilament described in step (2) is 5 times.

[0041] The setting process described in step (2) is hot air setting, and the setting temperature is 150℃.

[0042] The specific gravity of the obtained polypropylene foamed brush filaments was tested to be 0.57 g / cm³. 3 The bending strength is 78mN, and the average bending recovery rate of a single filament is 60%.

[0043] Example 2

[0044] This embodiment provides a method for preparing lightweight and soft polypropylene foamed brush filaments, including the following steps:

[0045] (1) Mix 80% polypropylene (PP), 19.38% linear low-density polyethylene (LLDPE), 0.02% diffusion oil, 0.1% colorant and 0.5% foaming agent evenly in a mixer;

[0046] (2) The mixture obtained in step (1) is added to a single screw extruder and extruded from the spinneret. After cooling, shaping, stretching, and shaping, it is finally wound and cut to obtain polypropylene foamed brush filaments with a diameter of 0.45 mm and light and soft texture.

[0047] Among them, the melt index of polypropylene in step (1) is 2-8 g / 10 min, and the test conditions are 230℃ and 2.16 kg.

[0048] The foaming agent mentioned in step (1) is an AC foaming agent (azodicarbonamide) with a decomposition temperature of 160-220℃.

[0049] The filter screen of the extruder mentioned in step (1) is a multi-layer filter screen with different mesh sizes ranging from 60 to 400.

[0050] The extruder head temperature in step (1) is set to 170°C.

[0051] The speed of the extruder in step (1) is preferably 30 RPM.

[0052] When extruding from the spinneret as described in step (2), the extruder temperature is set to 170-190℃. Conventional extruders are divided into several sections such as melting, compression, and metering. Depending on the material, the temperature of each section is set between 170-210℃.

[0053] The cooling and shaping process described in step (2) uses a cooling and shaping temperature of 5°C.

[0054] The stretching ratio of the monofilament described in step (2) is 3 times.

[0055] The shaping process described in step (2) is hot water shaping at a temperature of 70°C.

[0056] The specific gravity of the obtained polypropylene foamed brush filaments was tested to be 0.62 g / cm³.3 The bending strength is 100mN, and the average bending recovery rate of a single filament is 50%.

[0057] Example 3

[0058] This embodiment provides a method for preparing lightweight and soft polypropylene foamed brush filaments, including the following steps:

[0059] (1) Mix 90% polypropylene (PP), 7.44% linear low-density polyethylene (LLDPE), 0.06% diffusion oil, 0.5% colorant and 2% foaming agent evenly in a mixer;

[0060] (2) The mixture obtained in step (1) is added to a single screw extruder and extruded from the spinneret. After cooling, shaping, stretching, and shaping, it is finally wound and cut to obtain polypropylene foamed brush filaments with a diameter of 0.45 mm and light and soft texture.

[0061] In step (1), the melt index of the polypropylene is 2-8 g / 10 min, and the test conditions are 230℃ and 2.16 kg.

[0062] The foaming agent mentioned in step (1) is an AC foaming agent (azodicarbonamide) with a decomposition temperature of 160-220℃.

[0063] The filter screen of the extruder mentioned in step (1) is a multi-layer filter screen with different mesh sizes ranging from 60 to 400.

[0064] The extruder head temperature in step (1) is set to 190°C.

[0065] The speed of the extruder in step (1) is preferably 20 RPM.

[0066] When extruding from the spinneret as described in step (2), the extruder temperature is set to 190-210℃. Conventional extruders are divided into several sections such as melting, compression, and metering. Depending on the material, the temperature of each section is set between 170-210℃.

[0067] The cooling and shaping process described in step (2) uses a cooling and shaping temperature of 20°C.

[0068] The stretching ratio of the bristles described in step (2) is 7 times.

[0069] The shaping described in step (2) is hot air shaping at a temperature of 250°C.

[0070] The polypropylene foamed brush filaments were tested and found to have a specific gravity of 0.55 g / cm3, a flexural strength of 65 mN, and an average single filament flexural recovery rate of 69%.

[0071] Comparison Example 1

[0072] (1) Mix polypropylene (PP) and color masterbatch according to the formula: 99.5% polypropylene (PP) + 0.45% colorant + 0.05% diffusion oil evenly;

[0073] (2) Melt spinning. The above mixture is added to the hopper of an extruder, and after melt extrusion, cooling and shaping, stretching and shaping, it is finally wound and cut to produce polypropylene brush filaments with a diameter of 0.45 mm;

[0074] The extruder head temperature is 180℃, the rotation speed is set to 40m / min, the monofilament stretch ratio is 5 times, and the hot air setting temperature is 200℃.

[0075] The polypropylene brush filaments were tested and found to have a specific gravity of 0.90 g / cm3, a bending strength of 251 mN, and an average bending recovery rate of 33% per filament.

[0076] The same spinning mold was used in both Example 1 and Comparative Example 1, meaning that the resulting brush filaments had the same diameter. The bending strength represents the softness of the brush filaments. In summary, the polypropylene foamed brush filaments treated in Example 1 are lighter and softer than the untreated brush filaments.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lightweight and soft polypropylene foamed brush bristle, characterized in that: It is composed of the following components in weight percentage: 70%–90% polypropylene, 5%–25% linear low-density polyethylene, 0.02%–1% dispersant, 0%–5% colorant, and 0.2%–5% foaming agent; The melt index of the polypropylene is 2-8 g / 10 min, and the test conditions are: 230℃, 2.16 kg. The dispersant is a diffusion oil; The foaming agent is a foaming agent with a decomposition temperature of 160-220℃; The foaming agent is AC foaming agent; The method for preparing the lightweight and soft polypropylene foamed brush filaments includes the following steps: (1) 70%–90% polypropylene, 5%–25% linear low-density polyethylene, 0.02%–1% dispersant, 0%–5% colorant, and 0.2%–5% foaming agent are added to a mixer and stirred until homogeneous to form a mixture; (2) The mixture obtained in step (1) is added to a single screw extruder, extruded from the spinneret, cooled and shaped, stretched and shaped, and finally wound and cut to obtain lightweight and soft polypropylene foamed brush filaments. The cooling and shaping process described in step (2) uses a cooling and shaping temperature of 5-20℃. The stretching ratio of the monofilament described in step (2) is 3-7 times.

2. The lightweight and soft polypropylene foamed brush filaments according to claim 1, characterized in that: The decomposition temperature range of the foaming agent is consistent with the melting temperature range of the polypropylene.

3. The lightweight and soft polypropylene foamed brush filaments according to claim 1, characterized in that: The filter screen of the extruder mentioned in step (1) is a multi-layer filter screen with a mesh size range of 60-400. The extruder head temperature in step (1) is set to 170-190℃; The speed of the extruder in step (1) is 20-30 RPM.

4. The method for preparing lightweight and soft polypropylene foamed brush filaments according to claim 1, characterized in that: When extruding from the spinneret as described in step (2), the extruder temperature is set to 170-230℃.

5. The method for preparing lightweight and soft polypropylene foamed brush filaments according to claim 1, characterized in that: The shaping temperature mentioned in step (2) is 70-250℃.

6. The lightweight and soft polypropylene foamed bristles according to any one of claims 1-5 are used in cleaning brushes, kitchen brushes, and household brushes.