White master batch for polypropylene spun-bonded non-woven fabric with low pressure filtration difference and non-sticky holes and preparation method of white master batch

Abstract

The invention particularly relates to a white master batch for a polypropylene spun-bonded non-woven fabric with low pressure filtration difference and non-sticking holes and a preparation method of the white master batch. The white master batch is prepared from the following raw materials in parts by weight: 50 to 70 parts of titanium dioxide, 0 to 20 parts of barium sulfate, 0.4 to 0.8 part of compound antioxidant, 0.2 to 0.5 part of zinc stearate, 2 to 4 parts of coupling agent, 4 to 6 parts of macromolecular processing aid, 10 to 16 parts of elastomer TPE (Thermoplastic Polyethylene) and 10 to 30 parts of polypropylene. According to the white master batch prepared by the invention, the macromolecular processing aid is quantitatively injected at the rear end of the screw rod, so that the consumption of the macromolecular processing aid by equipment and machines in the processing process of the color master batch is reduced to the maximum extent, and the color master batch is ensured to contain sufficient macromolecular processing aid. In the subsequent non-woven fabric production process, the apparent viscosity of materials in the screw and generation of coking materials are reduced, and the phenomena of melt fracture and spinneret orifice accumulated material blockage are reduced or even eliminated. And the replacement period of the spun-bonded non-woven fabric spinneret plate is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of waste material recycling and reuse, and particularly relates to a white masterbatch for polypropylene spunbond non-woven fabric with low pressure filtration difference and non-sticking holes and a preparation method thereof. Background Art

[0002] Non-woven fabric (English name: Non Woven Fabric or Nonwoven cloth), also known as non-woven fabric, is a kind of non-woven fabric composed of oriented or random fibers. It is a new generation of environmental protection material, with the characteristics of moisture-proof, breathable, flexible, light in weight, non-flammable, easy to decompose, non-toxic and non-irritating, rich in colors, low in price, recyclable, etc.

[0003] The currently common production processes for non-woven fabrics are the spunbond method and the meltblown method. Spunbond non-woven fabric is to extrude and stretch the polymer to form continuous filaments, then lay the filaments into a web, and the web is further processed by self-bonding, thermal bonding, chemical bonding or mechanical reinforcement methods to turn the web into a non-woven fabric. Meltblown non-woven fabric is to use high-speed hot air to stretch the polymer melt stream extruded from the spinneret holes of the die head, thereby forming ultrafine fibers and aggregating them on the coagulation net curtain or drum, and becoming a non-woven fabric by relying on self-bonding.

[0004] The fibers used in non-woven fabric production are mainly polypropylene (PP) and polyester (PET). In addition, there are also polyamide (PA), viscose fiber, acrylic fiber, polyethylene (HDPE), and polyvinyl chloride (PVC).

[0005] Non-woven fabric breaks through the traditional textile principle and has the characteristics of short process flow, fast production speed, high output, low cost, wide use, and multiple raw material sources. For polypropylene spunbond white non-woven fabric, the problems of easy blockage of the filter screen (resulting in shutdown due to too high web pressure), blockage of the spinneret holes (requiring replacement of the spinneret plate), filament breakage, and lack of luster on the surface have always troubled non-woven fabric producers.

[0006] In the existing color masterbatch technology for non-woven fabrics, the invention patent CN102336949A (invalid) discloses a white masterbatch for PP spunbond non-woven fabrics, which is characterized in that it is mainly made of rutile titanium dioxide, heavy calcium carbonate, super-dispersing modifier, POE and polypropylene. The weight ratio of rutile titanium dioxide, heavy calcium carbonate, super-dispersing modifier, POE and polypropylene is (95 - 105):(25 - 35):(1 - 3):(15 - 25):(1 - 3). In this invention, the use of heavy calcium carbonate makes it difficult to control the pressure filtration difference and unable to continuously produce for a long time. The invention patent CN102807704A (invalid) discloses a spunbond non-woven fabric masterbatch and its manufacturing method, which is characterized in that the spunbond non-woven fabric masterbatch includes a masterbatch matrix made of a composite plastic material, and the composite plastic material includes inorganic powder, carrier resin, lubricant, dispersant, coupling agent. The manufacturing method of the spunbond non-woven fabric masterbatch includes the following steps: 1) Mixing of the composite plastic material: Put the composite plastic material including inorganic powder, carrier resin, lubricant, dispersant, coupling agent into a mixer and stir at a temperature of 95 - 130 °C to make a mixed material. 2) Extrusion granulation of the mixed material: Add the mixed material into a twin-screw extruder for extrusion, die-face hot cutting and granulation to obtain the spunbond non-woven fabric masterbatch. This invention discloses a high-filled masterbatch, not a white masterbatch, and it is difficult to control the pressure filtration difference and unable to continuously produce for a long time. Summary of the Invention

[0007] The purpose of the present invention is to provide a white masterbatch with an extremely low pressure filtration difference of the filter screen. Adding 1 - 4% of the white masterbatch to polypropylene to produce spunbond non-woven fabrics, the extrusion pressure fluctuation of the extruder is small, it can continuously produce for a long time without replacing the filter screen, reduce the number of shutdowns, and reduce production losses.

[0008] Another purpose of the present invention is to provide a white masterbatch that does not stick to the spinneret holes and does not block the spinneret holes. Adding a certain amount of high molecular processing aids to the white masterbatch can greatly reduce the apparent viscosity of the material, reduce or even eliminate the melt fracture phenomenon and the accumulation and blockage of the spinneret holes. Thus, the replacement cycle of the spunbond non-woven fabric spinneret plate is extended.

[0009] In order to solve the above technical problems, the present invention adopts the following technical solutions: A white masterbatch for low-pressure filtration difference and non-sticking holes of polypropylene spunbond non-woven fabrics, comprising the following raw materials in parts by weight: Titanium dioxide: 50 - 70 parts Barium sulfate: 0 - 20 parts Compound antioxidant: 0.4 - 0.8 parts Zinc stearate: 0.2 - 0.5 parts Coupling agent: 2 - 4 parts High molecular processing aids: 4 - 6 parts Elastomer TPE: 10 - 16 parts Polypropylene: 10 - 30 parts.

[0010] Preferably, the polymer processing aid includes one or more of organically modified polysiloxane and silicone-based processing aids.

[0011] Preferably, the polymer processing aid includes the organically modified polysiloxane and the silicone-based processing aid in a ratio of 70 - 80:20 - 30.

[0012] Preferably, the compound antioxidant is composed of a phenolic antioxidant and a phosphorus-based antioxidant.

[0013] Preferably, in the compound antioxidant, the weight ratio of the phenolic antioxidant to the phosphorus-based antioxidant is 20 - 40:60 - 80.

[0014] Preferably, the coupling agent includes one or more of silane coupling agents, titanate coupling agents, aluminate coupling agents, and bimetallic coupling agents.

[0015] Preferably, the titanium dioxide includes nanoscale rutile titanium dioxide; the barium sulfate includes nanoscale precipitated barium sulfate.

[0016] The inorganic pigment selected in the present invention is nanoscale titanium dioxide, and the filler is nanoscale barium sulfate, which has a small fineness and good passability through the filter screen and spinneret holes. However, since they are all nanoscale inorganic substances, they are very easy to agglomerate into large aggregates, which has a great impact on the subsequent spunbond nonwoven fabric processing. Therefore, the present invention also provides a dispersion treatment technology for white masterbatch to solve the dispersion problem of nanoscale inorganic substances in polypropylene resin. Through the high shear force of continuous kneading, the aggregates of inorganic substances are opened, so that the inorganic substances are evenly dispersed in the polypropylene resin, and a coupling agent is added to make the inorganic substances and polyolefins fully adhered, so that the filaments of the subsequent spunbond nonwoven fabric products have a uniform hue, high gloss, and no broken filaments.

[0017] Preferably, the melt index coefficient of the polypropylene is 60 - 100 g / 10min.

[0018] A preparation method of a white masterbatch for the above-mentioned low-pressure differential pressure and non-sticking hole polypropylene spunbond nonwoven fabric includes the following steps: A. Mix the titanium dioxide, the barium sulfate, the elastomer TPE, the polypropylene, the compound antioxidant, the zinc stearate, and the coupling agent evenly at low temperature according to the ratio to obtain a mixed material; B. Then carry out kneading and mixing of the mixed material to obtain a melt; C. Then extrude the melt, and inject the polymer processing aid while extruding to obtain an extruded material; D. Subsequently, granulate the extruded material and then cool it to obtain particles. E. Subsequently, after dehydrating, drying, and screening the particles, obtain the white masterbatch for low-pressure differential pressure and non-sticky pore polypropylene spunbond non-woven fabric.

[0019] Preferably, in step A, the low temperature is 60-65°C; in step B, the conditions for internal mixer kneading include: internal mixer temperature 100-110°C, internal mixer rotation speed 500-600 r / min, internal mixer kneading time ≤ 300 s; in step C, the conditions for extrusion include: extrusion temperature 200-220°C, extrusion rotation speed 25-35 rpm / min; in step D, the granulation includes hot granulation, granulation die head temperature 200-230°C, granulation rotation speed 1300-1600 rpm / min.

[0020] Preferably, steps A and B are carried out in a continuous double-rotor internal mixer; step C is carried out in a screw extruder; step D is carried out in an underwater granulator; step E is carried out in a dehydrator; in step C, the polymer processing aid is injected through a side feeding port provided at the rear end of the screw of the screw extruder; in step E, the particles are transported to the dehydrator through a water medium.

[0021] Compared with the prior art, implementing the present invention has the following beneficial effects: 1. Select nano-level titanium dioxide and barium sulfate, and produce a white masterbatch with extremely excellent dispersibility through an excellent production process, and its differential pressure filtration value ≤ 2 bar.

[0022] 2. For the white masterbatch prepared by the present invention, the polymer processing aid is quantitatively injected at the rear end of the screw, minimizing the consumption of the polymer processing aid by the equipment during the processing of the masterbatch, ensuring that the masterbatch contains a sufficient amount of the polymer processing aid. In the subsequent non-woven fabric production process, it reduces the apparent viscosity of the material in the screw and the generation of coked substances, reduces or even eliminates the melt fracture phenomenon and the blockage of the spinneret holes by accumulated materials. It prolongs the replacement cycle of the spunbond non-woven fabric spinneret.

[0023] 3. The present invention selects TPE as a toughening agent, which can effectively increase the flexibility of the non-woven fabric while ensuring the tensile strength of the spunbond non-woven fabric remains unchanged. Specific Embodiments

[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments.

[0025] Example 1 The formulation of the white masterbatch, by weight: Titanium dioxide: 70 parts Compound antioxidant: 0.4 parts Zinc stearate: 0.5 parts Coupling agent: 3.1 parts Polymer processing aid: 6 parts Elastomer TPE: 10 parts Polypropylene: 10 parts The preparation steps are as follows: 1) Put titanium dioxide, TPE and polypropylene into the designated large hopper respectively, mix 0.1 parts by weight of phenolic antioxidant, 0.3 parts by weight of phosphorus antioxidant, 0.5 parts by weight of zinc stearate, 1.5 parts by weight of silane coupling agent and 1.6 parts by weight of titanate coupling agent evenly according to the formula ratio, put them into the auxiliary agent hopper, mix 4.5 parts by weight of organic modified polysiloxane and 1.5 parts by weight of silicone processing aid evenly and put them into the designated auxiliary agent hopper separately; 2) 70 parts by weight of titanium dioxide, 10 parts by weight of TPE, 10 parts by weight of polypropylene, and 4 parts by weight of mixing aids were accurately weighed by an automatic weighing scale and then placed into the inlet of a continuous twin-rotor internal mixer; 3) The temperature at the inlet of the continuous twin-rotor internal mixer is 65°C. The materials are fully mixed at low temperature and then enter the internal mixing chamber for kneading. The chamber temperature is 110°C, the internal mixing speed is 600r / min, and the internal mixing kneading time is 280s to knead the materials into a melt; 4) The melt falls from the mixer outlet to the screw extruder inlet, and the screw extrusion temperature is set to 220°C and the extrusion speed is set to 25 rpm / min. At the rear end of the screw, 6 parts by weight of polymer processing aid are quantitatively injected through the side feed port, and finally transported to the underwater pelletizer; 5) The material is granulated by an underwater granulator, with a die temperature of 230°C and a rotation speed of 1300 rpm / min, and then water-cooled and transported to a dehydrator through a water medium; 6) After dehydration, drying and screening, the particles are obtained to obtain white masterbatch for spunbond nonwoven fabrics.

[0026] Example 2 The formula of white masterbatch is calculated by weight: Titanium dioxide: 60 parts Compound antioxidant: 0.6 parts Zinc stearate: 0.4 parts Coupling agent: 2.5 parts Polymer processing aid: 5 parts Elastomer TPE: 14 parts Polypropylene: 17.5 parts The preparation steps are as follows: 1) Put titanium dioxide, TPE, and polypropylene into the designated large hoppers respectively. Mix 0.2 parts by weight of phenolic antioxidant, 0.4 parts by weight of phosphorus antioxidant, 0.4 parts by weight of zinc stearate, 1.2 parts by weight of silane coupling agent, and 1.3 parts by weight of bimetallic coupling agent evenly according to the formula ratio, and put them into the additive hopper. Put 3.75 parts by weight of organically modified polysiloxane and 1.25 parts by weight of organosilicon processing aid into the designated additive hoppers separately; 2) Precisely weigh 60 parts by weight of titanium dioxide, 14 parts by weight of TPE, 17.5 parts by weight of polypropylene, and 3.5 parts by weight of mixed additives through an automatic weighing scale, and put them into the inlet of a continuous double-rotor internal mixer; 3) The temperature at the inlet of the continuous double-rotor internal mixer is 65°C. Mix the materials evenly at a low temperature, and then enter the mixing cavity for kneading. The cavity temperature is 110°C, the internal mixing speed is 550 r / min, and the internal mixing and kneading time is 260 s to knead the materials into a melt; 4) The melt drops from the outlet of the internal mixer to the inlet of the screw extruder. Set the screw extrusion temperature to 210°C and the extrusion speed to 28 rpm / min. At the rear end of the screw, quantitatively inject 5 parts by weight of polymer processing aid through the side feeding port, and finally transport it to the underwater pelletizer; 5) Thermally pelletize the materials through the underwater pelletizer. The die head temperature is 220°C and the speed is 1400 rpm / min, and then perform water cooling and transport it to the dehydrator through the water medium; 6) After the particles are dehydrated, dried, and screened, white masterbatch for spunbond nonwoven fabric is obtained.

[0027] Example 3 The formula of the white masterbatch, by weight parts: Titanium dioxide: 60 parts Barium sulfate: 10 parts Compound antioxidant: 0.5 part Zinc stearate: 0.5 part Coupling agent: 3.5 parts Polymer processing aid: 5 parts Elastomer TPE: 10.5 parts Polypropylene: 10 parts The preparation steps are as follows: 1) Put titanium dioxide, barium sulfate, TPE, and polypropylene into the designated large hoppers respectively. Mix 0.17 part by weight of phenolic antioxidant, 0.33 part by weight of phosphorus antioxidant, 0.5 part by weight of zinc stearate, 2 parts by weight of silane coupling agent, and 1.5 parts by weight of aluminate coupling agent evenly according to the formula ratio, and put them into the additive hopper. Put 3.5 parts by weight of organically modified polysiloxane and 1.5 parts by weight of organosilicon processing aid into the designated additive hoppers separately; 2) Precisely weigh 60 parts by weight of titanium dioxide, 10 parts by weight of barium sulfate, 10.5 parts by weight of TPE, 10 parts by weight of polypropylene, and 4.5 parts by weight of mixed additives using an automatic weighing scale, and then put them into the inlet of a continuous double-rotor internal mixer; 3) The temperature at the inlet of the continuous double-rotor internal mixer is 60 °C. Mix the materials evenly at a low temperature, and then enter the kneading chamber for kneading. The temperature of the chamber is 105 °C, the internal mixing speed is 550 r / min, and the internal mixing and kneading time is 280 s to knead the materials into a melt; 4) The melt drops from the outlet of the internal mixer to the inlet of the screw extruder. Set the screw extrusion temperature to 220 °C and the extrusion speed to 30 rpm / min. At the rear end of the screw, quantitatively inject 5 parts by weight of high molecular processing additives through the side feeding port, and finally convey them to an underwater pelletizer; 5) Thermally pelletize the materials using an underwater pelletizer. The die head temperature is 230 °C and the speed is 1400 rpm / min, and then perform water cooling and convey them to a dehydrator through a water medium; 6) After the particles are dehydrated, dried, and screened, white masterbatch for spunbond nonwoven fabric is obtained.

[0028] Example 4 The formula of the white masterbatch, by parts by weight: Titanium dioxide: 50 parts Barium sulfate: 10 parts Compound antioxidant: 0.8 part Zinc stearate: 0.4 part Coupling agent: 3 parts High molecular processing additive: 4 parts Elastomer TPE: 15 parts Polypropylene: 16.8 parts The preparation steps are as follows: 1) Put titanium dioxide, barium sulfate, TPE, and polypropylene into the designated large hoppers respectively. Mix 0.25 part by weight of phenolic antioxidant, 0.55 part by weight of phosphorus antioxidant, 0.4 part by weight of zinc stearate, 1 part by weight of silane coupling agent, 1 part by weight of titanate coupling agent, and 1 part by weight of aluminate coupling agent evenly according to the formula ratio, and put them into the additive hopper. Put 3.2 parts by weight of organically modified polysiloxane and 0.8 part by weight of organosilicon processing additive separately into the designated additive hopper; 2) Precisely weigh 50 parts by weight of titanium dioxide, 10 parts by weight of barium sulfate, 15 parts by weight of TPE, 16.8 parts by weight of polypropylene, and 4.2 parts by weight of mixed additives using an automatic weighing scale, and then put them into the inlet of a continuous double-rotor internal mixer; 3) The temperature at the inlet of the continuous double-rotor internal mixer is 60°C. The materials are fully mixed evenly at low temperature and then enter the internal mixing cavity for kneading. The cavity temperature is 100°C, the internal mixing speed is 500 r / min, and the internal mixing and kneading time is 250 s. The materials are kneaded into a melt. 4) The melt drops from the outlet of the internal mixer to the inlet of the screw extruder. The set screw extrusion temperature is 210°C, and the extrusion speed is 33 rpm / min. At the rear end of the screw, 4 parts by weight of polymer processing aids are quantitatively injected through the side feeding port, and finally it is transported to the underwater pelletizer. 5) The materials are hot pelletized by the underwater pelletizer. The die head temperature is 220°C, and the speed is 1420 rpm / min. Then it is water-cooled and transported to the dehydrator through the water medium. 6) After the particles are dehydrated, dried, and screened, white masterbatch for spunbond non-woven fabric is obtained.

[0029] Effect Example 1 The white masterbatch for spunbond non-woven fabric prepared in the above 4 examples was compared with Comparative Example 1 (non-woven fabric white masterbatch produced by a domestic enterprise) and Comparative Example 2 (special white masterbatch for non-woven fabric produced by a foreign enterprise) in terms of experimental performance. The results are shown in Table 1.

[0030] Table 1 Performance test results of the examples and Comparative Examples 1 and 2

[0031] In Table 1, ① melt index, pressure filtration difference, and moisture at 105°C are directly measured for the masterbatch; ② batch color difference is measured after adding 4% masterbatch to polypropylene and injection molding into a plate; ③ the filter screen used for the pressure filtration difference is 500 mesh, and the test weight is 1000 g.

[0032] From the melt index data, it can be concluded that the melt index of the white masterbatch of the 4 examples of the present invention is more than 20% higher than that of Comparative Examples 1 and 2, and it can be more quickly and evenly melted and mixed with non-woven fabric polypropylene, and is more suitable for high-speed spunbond non-woven fabric production.

[0033] From the batch color difference data, it can be concluded that the color difference of the 4 examples of the present invention is very small and the hue is very uniform and stable.

[0034] At present, most other masterbatch producers use the test method: adding a certain proportion of white masterbatch to the resin, mixing evenly and then testing the pressure filtration difference. Its accuracy and harshness are not as high as the method adopted by the present invention. From the 500-mesh pressure filtration difference data, it can be concluded that the pressure filtration differences of the 4 examples of the present invention are all less than 1 bar, far superior to Comparative Examples 1 and 2, and can effectively extend the screen changing cycle of downstream non-woven fabric production equipment.

[0035] From the moisture data, it can be concluded that the moisture control process of the present invention is superior to that of Comparative Examples 1 and 2.

[0036] Comparative Example 3 Maintaining the formulation ratio of Example 1, the mixing ratios of 6 parts by weight of the polymer processing aid in Example 1 were respectively changed to ① 6 parts by weight of a fluoropolymer processing aid, ② 6 parts by weight of an organically modified polysiloxane, ③ 6 parts by weight of a silicone-based processing aid, ④ 3 parts by weight of a fluoropolymer processing aid, 2 parts by weight of an organically modified polysiloxane, 1 part by weight of a silicone-based processing aid, ⑤ 1 part by weight of a fluoropolymer processing aid, 3 parts by weight of an organically modified polysiloxane, 2 parts by weight of a silicone-based processing aid, ⑥ 2 parts by weight of a fluoropolymer processing aid, 1 part by weight of an organically modified polysiloxane, 3 parts by weight of a silicone-based processing aid, ⑦ 3 parts by weight of an organically modified polysiloxane, 1 part by weight of a silicone-based processing aid. Comparative color masterbatch products were produced according to the production process of Example 1. Comparing the non-woven processing parameters with those of Example 1, the results are shown in Table 2.

[0037] Comparative Example 4 Maintaining the content of TPE in Example 1 changed from 10 parts by weight to 5 parts by weight, and the content of polypropylene changed from 10 parts by weight to 15 parts by weight. Comparative color masterbatch products were produced according to the production process of Example 1.

[0038] Effect Example 2 Comparing the non-woven processing parameters of Comparative Examples 3 and 4 with those of Example 1, the results are shown in Table 2.

[0039] Table 2 Comparison Results of Processing Parameters between Example 1 and Comparative Examples 3 and 4

[0040] It can be concluded from the data in Table 2 that the effect of ⑦ in Comparative Example 3 is the best.

[0041] Due to the chemical stability of PFAS (Per- and Polyfluoroalkyl Substances, i.e., per- and polyfluoroalkyl substances), they are not easily degraded in the environment, can accumulate in the environment and the human body, and pose a potential threat to human health and the ecosystem. Studies have shown that certain PFAS may have serious impacts on human health, such as affecting the reproductive system, development, immune system, and increasing the risk of cancer. In view of the potential hazards of PFAS, many countries and regions have begun to take measures to restrict their use. For the above reasons, through long-term research, the present invention finally arrives at an alternative solution without adding fluoropolymer processing aids. By selecting other types of processing aids and choosing a compounding formula of two types, namely mechanically modified polysiloxane and silicone-based processing aids, it is environmentally friendly and conforms to the current international trend of restricting fluorine-containing substances. Selecting an appropriate mixing ratio and cooperating with a certain amount of TPE has a better effect, can meet the ideal cycle requirements for the replacement of the filter screen and spinneret in non-woven fabric production, is conducive to the continuous production of spunbond non-woven fabric, with stable product performance, energy conservation, consumption reduction, environmental protection and low carbon.

[0042] Effect Example 3 Add 4% of the white masterbatches prepared in the above 4 examples and Comparative Examples 1 and 2 respectively to polypropylene, and produce spunbond non-woven fabric at the same processing temperature and speed, with a grammage of 20 ± 0.2 gsm. The processing parameters are compared as shown in Table 3, and the non-woven fabric properties are compared as shown in Table 4.

[0043] Table 3 Comparison Results of Processing Parameters between Examples and Comparative Examples

[0044] It can be concluded from the data in Table 3 that the replacement cycles of the filter screen and spinneret in the 4 examples of the present invention are much longer than those in the 2 comparative examples, which is more conducive to the continuous production of spunbond non-woven fabric, with more stable product performance, energy conservation, consumption reduction, environmental protection and low carbon.

[0045] Table 4 Comparison Results of Spunbond Non-woven Fabric Properties between Examples and Comparative Examples

[0046] It can be concluded from the data in Table 4 that from the data of tensile strength and elongation at break, it can be concluded that the white masterbatches of the 4 examples of the present invention are slightly better than those of Comparative Examples 1 and 2.

[0047] It can be concluded from the softness data that the 4 examples of the present invention are softer than Comparative Examples 1 and 2.

[0048] It can be concluded from the wear resistance grade data that the 4 examples of the present invention are the same as those of Comparative Examples 1 and 2.

[0049] It can be concluded from the whiteness data that the 4 examples of the present invention are whiter and have better gloss than Comparative Examples 1 and 2.

[0050] To sum up, the spunbond non-woven fabric produced by the 4 examples of the present invention has moderate tensile properties and wear resistance grade, better softness, and better whiteness and gloss.

[0051] The above-disclosed are only the preferred embodiments of the present invention. Of course, the scope of the rights of the present invention cannot be limited thereby. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A white masterbatch for polypropylene spunbond nonwoven fabric with low pressure filtration difference and non-sticky pores, characterized in that: The invention comprises the following raw materials in parts by weight: Titanium dioxide: 50~70 parts Barium sulfate: 0~20 parts Compound antioxidant: 0.4~0.8 parts Zinc stearate: 0.2~0.5 parts Coupling agent: 2~4 parts Polymer processing aid: 4~6 parts Elastomer TPE: 10~16 parts Polypropylene: 10~30 parts.

2. The white masterbatch for polypropylene spunbond nonwoven fabric with low pressure filtration difference and non-sticky pores according to claim 1, characterized in that: The polymer processing aid includes one or more of organic modified polysiloxane and organic silicon processing aid.

3. The white masterbatch for polypropylene spunbond nonwoven fabric with low pressure filtration difference and non-sticky pores according to claim 2, characterized in that: The polymer processing aid includes the organic modified polysiloxane and the organic silicon processing aid in a ratio of 70-80:20-30.

4. The white masterbatch for polypropylene spunbond nonwoven fabric with low pressure filtration difference and non-sticky pores according to claim 1, characterized in that: The compound antioxidant comprises a mixture of a phenolic antioxidant and a phosphorus antioxidant.

5. The white masterbatch for polypropylene spunbond nonwoven fabric with low pressure filtration difference and non-sticky pores according to claim 4, characterized in that: In the compound antioxidant, the weight ratio of the phenolic antioxidant to the phosphorus antioxidant is 20-40:60-80.

6. The white masterbatch for polypropylene spunbonded nonwoven fabric with low pressure filtration difference and non-sticky pores according to claim 1, characterized in that: The coupling agent includes one or more of a silane coupling agent, a titanate coupling agent, an aluminate coupling agent, and a bimetallic coupling agent; the titanium dioxide includes nano-scale rutile titanium dioxide; and the barium sulfate includes nano-scale precipitated barium sulfate.

7. The white masterbatch for polypropylene spunbonded nonwoven fabric with low pressure filtration difference and non-sticky pores according to claim 1, characterized in that: The melt index coefficient of the polypropylene is 60-100 g / 10 min.

8. A method for preparing the white masterbatch for polypropylene spunbonded nonwoven fabric with low pressure filtration difference and non-sticky pores according to claim 1, characterized in that: The steps include: A. uniformly mix the titanium dioxide, the barium sulfate, the elastomer TPE, the polypropylene, the compound antioxidant, the zinc stearate, and the coupling agent at low temperature according to a certain proportion to obtain a mixed material; B, then the mixed material is subjected to banburying and kneading to obtain a melt; C. then extruding the melt, and injecting the polymer processing aid during extrusion to obtain an extruded material; D. Then, granulating the extruded material and cooling it to obtain particles; E. Then, the particles are dehydrated, dried, and screened to obtain the white masterbatch for the polypropylene spunbond nonwoven fabric with low pressure filtration difference and non-sticky pores.

9. The preparation method according to claim 8, characterized in that: In step A, the low temperature includes 60-65° C.; in step B, the conditions of the banburying and kneading include: a banburying temperature of 100-110° C., a banburying speed of 500-600 r / min, and a banburying and kneading time of ≤300 s; in step C, the conditions of the extrusion include: an extrusion temperature of 200-220° C., and an extrusion speed of 25-35 rpm / min; in step D, the granulation includes hot granulation, a granulation die temperature of 200-230° C., and a granulation speed of 1300-1600 rpm / min.

10. The preparation method according to claim 8, characterized in that: Step A and step B are carried out in a continuous twin-rotor internal mixer; step C is carried out in a screw extruder; step D is carried out in an underwater granulator; and step E is carried out in a dehydrator; in step C, the polymer processing aid is injected through a side feeding port arranged at the rear end of the screw of the screw extruder; in step E, the particles are transported to the dehydrator through an aqueous medium.

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