阅读说明：本技术 一种熔喷无纺布的制备方法 (Preparation method of melt-blown non-woven fabric ) 是由 郑海刚 徐悦 于 2021-08-28 设计创作，主要内容包括：本申请涉及一种熔喷无纺布的制备方法。通过预先使用[N,N-二(2-乙基-7-苯基-1H-茚基)对乙苯磺酰胺]Ce催化制备均聚丙烯树脂,确保均聚丙烯树脂的分子量介于180000-200000之间；分子量分布为1.3-1.4之间；熔体指数介于18-22g/10min；残余应力比不高于0.03%。所得到的均聚丙烯树脂的分子量分布、熔体指数、残余应力比、柔性触感等性能均处于更为优异的水平,特别适于熔喷无纺布的制备,并可以得到兼具强度和柔性触感的无纺布。(The application relates to a preparation method of melt-blown non-woven fabric. Preparing homopolymerized propylene resin by using [ N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzene sulfonamide ] Ce for catalysis in advance, and ensuring that the molecular weight of the homopolymerized propylene resin is between 180000-200000; the molecular weight distribution is between 1.3 and 1.4; the melt index is between 18 and 22g/10 min; the residual stress ratio is not higher than 0.03%. The obtained homopolymerized propylene resin has more excellent molecular weight distribution, melt index, residual stress ratio, flexible touch feeling and other performances, is particularly suitable for preparing melt-blown non-woven fabrics, and can obtain the non-woven fabrics with both strength and flexible touch feeling.)

1. A preparation method of homopolypropylene resin for preparing melt-blown non-woven fabrics is characterized by comprising the following steps:

(1) loading [ N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzene sulfonamide ] Ce on the surfaces of alumina or silica particles to obtain a solid particle-loaded rare earth organic catalyst;

(2) the rare earth organic catalyst loaded by solid particles is used for preparing the homopolymerization propylene resin, and the polymerization temperature is 25-40 ℃;

wherein the structural formula of the [ N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzene sulfonamide ] Ce is shown as a formula (I),

（I）。

2. the method of claim 1, wherein the [ N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzene sulfonamide ] Ce is prepared by the steps of:

(1) preparing a toluene/tetrahydrofuran mixed solvent according to a volume ratio of 7:3, dissolving 0.05 mol of 2-ethyl-7-phenyl-1H-indene in 100 ml of the toluene/tetrahydrofuran mixed solvent to obtain a solution A,

(2) dripping 10 ml of 2mol/L cyclohexane solution of n-butyllithium into the solution A, and stirring for 3-12 hours;

(3) slowly dripping 100 ml of benzene solution of N, N-dichloro-p-ethylbenzene sulfonamide with the concentration of 0.025mol/L into the solution obtained in the step (2) in an environment below-20 ℃, stirring for 5 minutes, continuously stirring at room temperature for 12-24 hours, obtaining an intermediate product N, N-bis (2-ethyl-7-phenyl-1H-indenyl) benzenesulfonamide after the reaction is finished, removing the solvent in the reaction solution under reduced pressure, and then dissolving and recrystallizing by using a toluene solvent again to obtain high-purity N, N-bis (2-ethyl-7-phenyl-1H-indenyl) benzenesulfonamide;

(4) reacting ammonium cerium nitrate with sodium tert-butoxide in a molar ratio of 1:6 to obtain tetra-tert-butoxycerium;

(5) dissolving 0.025mol of N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzene sulfonamide prepared in the step (3) in 200 ml of tetrahydrofuran solution to obtain solution B, mixing 100 ml of tetrahydrofuran solution of cerium tetra-tert-butoxide with the concentration of 0.125mol/L with the solution B, and stirring for reaction for 12-24 hours to obtain the rare earth organic compound shown in the formula (I);

(6) the solvent in the reaction solution was removed under reduced pressure, and then redissolved and recrystallized in a toluene solvent to obtain high-purity [ N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzenesulfonamide ] Ce.

3. A homopolypropylene resin produced by the production method as described in claim 1 or 2, characterized in that the homopolypropylene resin has a molecular weight of 180000-200000; the molecular weight distribution is between 1.3 and 1.4; the melt index is between 18 and 22 g/min; the residual stress ratio is not higher than 0.03%.

4. A method for producing a melt-blown nonwoven fabric using the homopolypropylene resin according to claim 3, comprising the steps of:

(1) mixing the homopolypropylene resin and the electret master batch according to the weight ratio of (95-99) to (1-5) in a mixer, wherein the rotation speed of the mixer is 90-180rpm, and the mixing time is 10-15 min;

(2) melting and mixing the mixed raw materials through a double-screw extrusion further machine, and extruding and granulating to obtain melt-blown master batches, wherein the melting temperature of the double-screw extrusion machine is 215-235 ℃, and the rotating speed of a screw is 120-180 rpm;

(3) melt-blowing and spinning the melt-blown master batch prepared in the step (2) through a screw extruder, cooling and solidifying the melt-blown master batch into fiber filaments through surrounding cold air media, laying the fiber filaments on a receiving device to form a web, and forming a multilayer composite fiber web, wherein the air pressure is 0.3-0.5MPa and the receiving distance is 11-15cm in the melt-blowing process;

(4) and carrying out hot rolling reinforcement treatment on the multilayer composite fiber web to obtain the non-woven fabric, wherein the temperature of the hot rolling reinforcement treatment is 170 ℃, the pressure is 5MPa, and the hot rolling time is 15 s.

Technical Field

The application belongs to the technical field of manufacture of non-woven fabrics, and particularly relates to a preparation method of melt-blown non-woven fabrics.

Background

A nonwoven fabric is a fabric that is made of oriented or random fibers that have been mechanically and chemically treated without weaving to have an appearance similar to that of a conventional woven fabric. At present, there are mainly 7 types of non-woven fabric production processes, which are spunlace non-woven fabrics, heat seal non-woven fabrics, pulp and dreg air-laid non-woven fabrics, wet-process non-woven fabrics, spun-bonded non-woven fabrics, melt-blown non-woven fabrics and needle-punched non-woven fabrics. The melt-blown non-woven fabric has the advantages of good uniformity of fiber webs, soft hand feeling, good filterability and liquid absorbability and the like, and is widely applied to the fields of medical treatment, health, clothing and the like.

The fibers used to make the nonwoven fabric are typically synthetic fibers of polymeric materials such as polypropylene, chitosan, cellulose, and the like. The polyolefin resin synthetic fiber is the most common non-woven fabric fiber, has good flexibility and air permeability, and is widely applied to the fields of medical treatment and health, clothing, automobiles, buildings and the like. Among them, the properties of polyolefin resin directly determine the properties of the polyolefin nonwoven fabric obtained.

Improved flexibility can be obtained by using conventional ziegler-natta catalysts to synthesize homopolyolefin resins, and in particular by ziegler-natta catalysts to catalyze the bicomponent copolymerization of polypropylene and polyethylene. However, the resin fiber obtained by this method is not suitable for producing a high-strength nonwoven fabric due to deterioration of strength.

By preparing a homopolypropylene resin using a metallocene catalyst, an acrylic resin having a narrow molecular weight distribution can be obtained, which in turn enables the production of fine and uniform fibers and is used to prepare a high-strength nonwoven fabric. However, such a high-strength nonwoven fabric has poor soft touch and is not suitable for use in the fields of clothing, sanitary goods, and the like.

Therefore, the application aims to provide a preparation method of the melt-blown non-woven fabric which is particularly suitable for being applied in the fields of clothing, sanitary products and the like.

Disclosure of Invention

Aiming at the defects in the related art, the application provides a preparation method of melt-blown non-woven fabric, and the prepared melt-blown non-woven fabric has excellent strength and flexible touch.

In order to realize the application, as one aspect of the application, firstly, a homopolymerized propylene resin prepared by catalysis of a rare earth organic catalyst is provided, wherein the rare earth organic catalyst is a rare earth organic compound shown as a formula (I);

（I）

the molecular weight of the obtained homopolymerized propylene resin is between 180000 and 200000; the molecular weight distribution is between 1.3 and 1.4; the melt index is between 18 and 22 g/min; the residual stress ratio is not higher than 0.03%.

In order to achieve the present application, as another aspect of the present application, there is provided a method for preparing a rare earth organic compound represented by formula (I).

In the preparation method, the raw materials used comprise: n, N-dichloro-p-ethylbenzene sulfonamide, 2-ethyl-7-phenyl-1H-indene, benzene, toluene, cyclohexane, tetrahydrofuran, N-butyl lithium, ammonium ceric nitrate and sodium tert-butoxide. Wherein, the structural formulas of the N, N-dichloro-p-ethylbenzene sulfonamide and the 2-ethyl-7-phenyl-1H-indene are respectively shown as the following formulas (II) and (III).

（II）； （III）。

The preparation method of the rare earth organic compound shown in the formula (I) comprises the following steps:

(1) preparing a toluene/tetrahydrofuran mixed solvent according to a volume ratio of 7:3, dissolving 0.05 mol of 2-ethyl-7-phenyl-1H-indene in 100 ml of the toluene/tetrahydrofuran mixed solvent to obtain a solution A,

(2) dripping 10 ml of 2mol/L cyclohexane solution of n-butyllithium into the solution A, and stirring for 3-12 hours;

(3) slowly dripping 100 ml of benzene solution of N, N-dichloro-p-ethylbenzene sulfonamide with the concentration of 0.025mol/L into the solution obtained in the step (2) in an environment below-20 ℃, stirring for 5 minutes, continuously stirring at room temperature for 12-24 hours, obtaining an intermediate product N, N-bis (2-ethyl-7-phenyl-1H-indenyl) benzenesulfonamide after the reaction is finished, removing the solvent in the reaction solution under reduced pressure, and then dissolving and recrystallizing by using a toluene solvent again to obtain high-purity N, N-bis (2-ethyl-7-phenyl-1H-indenyl) benzenesulfonamide;

(4) reacting ammonium cerium nitrate with sodium tert-butoxide in a molar ratio of 1:6 to obtain tetra-tert-butoxycerium;

(5) dissolving 0.025mol of N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzene sulfonamide prepared in the step (3) in 200 ml of tetrahydrofuran solution to obtain solution B, mixing 100 ml of tetrahydrofuran solution of cerium tetra-tert-butoxide with the concentration of 0.125mol/L with the solution B, and stirring for reaction for 12-24 hours to obtain the rare earth organic compound shown in the formula (I);

(6) the solvent in the reaction solution was removed under reduced pressure, and then redissolved and recrystallized in a toluene solvent to obtain high-purity [ N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzenesulfonamide ] Ce.

To achieve the present application, as yet another aspect of the present application, there is provided a method for preparing a homopolypropylene resin catalyzed by a rare earth organic catalyst, comprising the steps of:

(1) loading [ N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzene sulfonamide ] Ce on the surfaces of alumina or silica particles to obtain a solid particle-loaded rare earth organic catalyst;

(2) the rare earth organic catalyst loaded by solid particles is used for catalyzing the preparation of homopolymerization propylene resin, and the polymerization temperature is 25-40 ℃.

Finally, in order to realize the present application, there is provided a method for preparing a melt-blown nonwoven fabric, comprising the steps of:

(1) the homopolymerized propylene resin prepared by the catalysis of the rare earth organic catalyst and the electret master batch are mixed in a mixer according to the weight ratio of (95-99) to (1-5), the rotating speed of the mixer is 90-180rpm, and the mixing time is 10-15 min;

(2) melting and mixing the mixed raw materials through a double-screw extrusion further machine, and extruding and granulating to obtain melt-blown master batches, wherein the melting temperature of the double-screw extrusion machine is 215-235 ℃, and the rotating speed of a screw is 120-180 rpm;

(3) and (3) carrying out melt-blown spinning on the melt-blown master batches prepared in the step (2) through a screw extruder, cooling and solidifying the melt-blown master batches into fiber filaments through surrounding cold air media, laying the fiber filaments on a receiving device to form a web, and forming a multi-layer composite fiber web, wherein the air pressure is 0.3-0.5MPa and the receiving distance is 11-15cm in the melt-blowing process.

(4) And carrying out hot rolling reinforcement treatment on the multilayer composite fiber web to obtain the non-woven fabric, wherein the temperature of the hot rolling reinforcement treatment is 170 ℃, the pressure is 5MPa, and the hot rolling time is 15 s.

Has the advantages that:

the inventor finds in practice that polyolefin resins prepared by catalysis of existing Ziegler-Natta catalysts or metallocene catalysts have the defects of insufficient strength or poor soft touch. According to the scheme of the application, the homopolymerized propylene resin is prepared by using the specific rare earth organic catalyst for catalysis, the molecular weight distribution, the melt index, the residual stress ratio, the flexible touch feeling and other properties of the obtained homopolymerized propylene resin are in more excellent levels, and the homopolymerized propylene resin is particularly suitable for preparing melt-blown non-woven fabrics and can obtain the non-woven fabrics with both strength and flexible touch feeling.

Detailed Description

The present application is further described in detail with reference to the following specific examples, and the content of the present application is not limited to the following examples. Variations that may occur to those skilled in the art are included in this application without departing from the scope of the inventive concept.

The inventors have found in practice that nonwoven fabrics produced by the meltblown process, although having a high softness, have relatively poor strength. In addition, the polyolefin resin prepared by the existing Ziegler-Natta catalyst has the defect of insufficient strength, and the polyolefin resin prepared by the existing metallocene catalyst has the defect of poor flexible touch. Therefore, the inventors found in the course of research for improving the above problems that the molecular weight of the homopolypropylene resin prepared by using the rare earth organic compound with a specific structure as the catalyst is 180000-200000, the molecular weight distribution is 1.3-1.4, the melt index is 18-22g/10min, and the ratio of the residual stress is not higher than 0.03%. Wherein the molecular weight, molecular weight distribution, melt index and residual stress ratio are optimized to 180000-.

Thus, according to a first embodiment according to the present application, there is provided a rare earth organic catalyst for catalyzing the preparation of homopolypropylene resins having the above-mentioned excellent properties. The rare earth organic catalyst is [ N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzene sulfonamide ] Ce, and has a structural formula shown in a formula (I),

（I）。

example 1

The preparation of [ N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzene sulfonamide ] Ce comprises the following steps:

(1) preparing a toluene/tetrahydrofuran mixed solvent according to a volume ratio of 7:3, dissolving 0.05 mol of 2-ethyl-7-phenyl-1H-indene in 100 ml of the toluene/tetrahydrofuran mixed solvent to obtain a solution A,

(2) dripping 10 ml of 2mol/L cyclohexane solution of n-butyllithium into the solution A, and stirring for 12 hours;

(3) slowly dripping 100 ml of benzene solution of N, N-dichloro-p-ethylbenzene sulfonamide with the concentration of 0.025mol/L into the solution obtained in the step (2) at the environment below-20 ℃, stirring for 5 minutes, continuously stirring at room temperature for 24 hours, obtaining an intermediate product N, N-bis (2-ethyl-7-phenyl-1H-indenyl) benzenesulfonamide after the reaction is finished, removing the solvent in the reaction solution under reduced pressure, and then dissolving and recrystallizing by using a toluene solvent again to obtain high-purity N, N-bis (2-ethyl-7-phenyl-1H-indenyl) benzenesulfonamide;

(4) reacting ammonium cerium nitrate with sodium tert-butoxide in a molar ratio of 1:6 to obtain tetra-tert-butoxycerium;

(5) dissolving 0.025mol of N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzene sulfonamide prepared in the step (3) in 200 ml of tetrahydrofuran solution to obtain solution B, mixing 100 ml of tetrahydrofuran solution of cerium tetra-tert-butoxide with the concentration of 0.125mol/L with the solution B, and stirring for reacting for 18 hours to obtain the rare earth organic compound shown in the formula (I);

(6) the solvent in the reaction solution was removed under reduced pressure, and then redissolved and recrystallized in a toluene solvent to obtain high-purity [ N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzenesulfonamide ] Ce.

Example 2

The preparation of [ N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzene sulfonamide ] Ce comprises the following steps:

(1) preparing a toluene/tetrahydrofuran mixed solvent according to a volume ratio of 7:3, dissolving 0.05 mol of 2-ethyl-7-phenyl-1H-indene in 100 ml of the toluene/tetrahydrofuran mixed solvent to obtain a solution A,

(2) dripping 10 ml of 2mol/L cyclohexane solution of n-butyllithium into the solution A, and stirring for 10 hours;

(3) slowly dripping 100 ml of benzene solution of N, N-dichloro-p-ethylbenzene sulfonamide with the concentration of 0.025mol/L into the solution obtained in the step (2) at the environment below-20 ℃, stirring for 5 minutes, continuously stirring at room temperature for 18 hours, obtaining an intermediate product N, N-bis (2-ethyl-7-phenyl-1H-indenyl) benzenesulfonamide after the reaction is finished, removing the solvent in the reaction solution under reduced pressure, and then dissolving and recrystallizing by using a toluene solvent again to obtain high-purity N, N-bis (2-ethyl-7-phenyl-1H-indenyl) benzenesulfonamide;

(4) reacting ammonium cerium nitrate with sodium tert-butoxide in a molar ratio of 1:6 to obtain tetra-tert-butoxycerium;

(5) dissolving 0.025mol of N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzene sulfonamide prepared in the step (3) in 200 ml of tetrahydrofuran solution to obtain solution B, mixing 100 ml of tetrahydrofuran solution of cerium tetra-tert-butoxide with the concentration of 0.125mol/L with the solution B, and stirring for reacting for 24 hours to obtain the rare earth organic compound shown in the formula (I);

(6) the solvent in the reaction solution was removed under reduced pressure, and then redissolved and recrystallized in a toluene solvent to obtain high-purity [ N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-ethylbenzenesulfonamide ] Ce.

In order to compare the difference in effect between the rare earth metal organic compound and the transition metal organic compound, comparative example 1 and comparative example 2 were provided. Of these, comparative example 2 is a prior art Ziegler-Natta catalyst.

Comparative example 1

Preparation of N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-toluenesulfonamide zirconium dichloride

The preparation method comprises the following specific steps:

(1) preparing a toluene/tetrahydrofuran mixed solvent according to a volume ratio of 7:3, dissolving 11 g of 2-ethyl-7-phenyl-1H-indene in 100 ml of the toluene/tetrahydrofuran mixed solvent to obtain a solution A,

(2) dripping 10 ml of 2mol/L cyclohexane solution of n-butyllithium into the solution A, and stirring for 10 hours;

(3) slowly dropwise adding 100 ml of benzene solution of N, N-dichloro-p-toluenesulfonamide with the concentration of 60g/L into the solution obtained in the step (2) at the environment below-20 ℃, stirring for 5 minutes, continuously stirring at room temperature for 16 hours, and obtaining an intermediate product N, N-bis (2-ethyl-7-phenyl-1H-indenyl) benzenesulfonamide after the reaction is finished;

(4) adding 100 ml of tetrahydrofuran solution of zirconium tetrachloride with the concentration of 0.025mol/L into the solution obtained in the step (3) at the temperature of below 20 ℃ below zero, stirring for 20 minutes, continuously stirring at room temperature for 24 hours, and obtaining the preparation of the N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-toluenesulfonamide zirconium dichloride after the reaction is finished;

(5) the solvent in the reaction solution was removed under reduced pressure, and then redissolved and recrystallized in toluene solvent to obtain high-purity N, N-bis (2-ethyl-7-phenyl-1H-indenyl) p-toluenesulfonamide zirconium dichloride.

According to a second embodiment of the present application, there is provided a homopolypropylene resin. Examples 3 to 4 and comparative examples 3 to 4 are provided so as to correspond to examples 1 to 2 and comparative examples 1 to 2 in the first embodiment. The preparation method of the homopolymerized propylene resin comprises the following steps:

(1) respectively loading the final products prepared in the examples 1-2 and the comparative example 1 on the surfaces of silica particles to obtain corresponding solid particle loaded metal organic catalysts;

(2) the 3 kinds of solid particle-supported organometallic catalysts obtained in (1) and the Ziegler-Natta catalyst of comparative example 2 were used for the preparation of a catalytic homopolypropylene resin, respectively, at a polymerization temperature of 25 ℃ and the homopolypropylene resins obtained were labeled as examples 3-4 and comparative examples 3-4, respectively.

According to a third embodiment of the present application, a meltblown nonwoven is provided. In order to correspond to examples 3 to 4 and comparative examples 3 to 4 in the second embodiment, examples 5 to 6 and comparative examples 5 to 6 were provided. The preparation method of the melt-blown non-woven fabric comprises the following steps:

(1) respectively putting the homopolymerized propylene resin of the embodiment 3-4 and the homopolymerized propylene resin of the comparative example 3-4 and the electret master batch into a mixer according to the weight ratio of 98:2 for mixing, wherein the rotating speed of the mixer is 120rpm, and the mixing time is 10 min;

(2) melting and mixing the mixed raw materials through a double-screw extrusion further machine, and extruding and granulating to obtain melt-blown master batches, wherein the melting temperature of the double-screw extrusion machine is 225 ℃, and the rotating speed of screws is 120 rpm;

(3) and (3) carrying out melt-blown spinning on the melt-blown master batches prepared in the step (2) through a screw extruder, cooling and solidifying the melt-blown master batches into fiber filaments through surrounding cold air media, laying the fiber filaments on a receiving device to form a web, and forming a multi-layer composite fiber web, wherein the air pressure in the melt-blowing process is 0.4MPa, and the receiving distance is 12 cm.

(4) And carrying out hot rolling reinforcement treatment on the multilayer composite fiber web, wherein the temperature of the hot rolling reinforcement treatment is 170 ℃, the pressure is 5MPa, and the hot rolling time is 15s, so as to obtain five kinds of non-woven fabrics which are respectively marked as examples 5-6 and comparative examples 5-6.

Testing of homopolypropylene resin and nonwoven Fabric

Test example 1

The evaluation of the properties of the homopolypropylene resin includes the following three aspects.

(1) Molecular Weight Distribution (MWD)

The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer were measured using gel permeation chromatography, and the Molecular Weight Distribution (MWD) was calculated by dividing the weight average molecular weight by the number average molecular weight.

(2) Melt index (g/10 min)

Measured at 230 ℃ under a load of 2.16Kg according to ASTM D1238 and expressed as the mass (g) of polymer melted and flowing out in 10 molecules.

(3) Ratio of residual stress

A strain of 200% was applied at 200 c, and then the change in residual stress after 10 seconds was measured. The sample was loaded between upper and lower plates having a diameter of 25mm using a DHR apparatus of watty science co, and then the gap was fixed to 5mm to measure residual stress data, and the residual stress ratio was calculated based on the measured residual stress data. The method for calculating the residual stress ratio comprises the following steps:

residual stress ratio = initial residual stress/residual stress after one minute

Wherein the initial residual stress is a residual stress at 0.1 second after applying 200% strain.

The evaluation results of the properties of the homopolypropylene resins of examples 3 to 4 and comparative examples 3 to 4 are shown in Table 1.

TABLE 1

	Molecular weight distribution	Melt index (g/10 min)	Ratio of residual stress (%)
				Example 3	1.3	19	0.02
Example 4	1.3	20	0.02
				Comparative example 3	2.4	28	0.04
Comparative example 4	3.1	33	0.16

As can be seen from Table 1, the homopolypropylene resins of examples 3 to 4 had a more optimized molecular weight distribution of 1.3 and a more optimized melt index of between 19 and 20g/10min, and a more optimized residual stress ratio of 0.02%. Compared with the homopolymerized propylene resin of comparative examples 3-4, the homopolymerized propylene resin prepared by the method is particularly suitable for preparing melt-blown non-woven fabrics, and is beneficial to obtaining the non-woven fabrics with both strength and flexible touch feeling.

Test example 2

The evaluation of the properties of the nonwoven fabric includes the following three aspects.

(1) Strength of nonwoven fabric

The tensile strength of the nonwoven fabric in the machine direction and the transverse direction was measured by a 5 cm-wide cut strip method according to the cutting method of ASTM D-5035.

(2) Hand feeling of nonwoven fabric

The fabric hand feeling comfort degree tester with the model number of No.070 of Shanghai product Kui electromechanical technology Limited company is adopted for hand feeling test, the evaluation is respectively carried out from toughness, softness and smoothness, the grade of the toughness is 0-100, and the higher the grade is, the better the toughness is; the softness score is 0-100, and the higher the score is, the better the softness is; the slip score is 0-100, the higher the score, the better the slip.

(3) Coefficient of friction of nonwoven fabric

The friction coefficient of the nonwoven fabric was measured using a friction coefficient measuring device. Specifically, the measurement was carried out using an MXD-01 friction coefficient meter.

The results of evaluating the properties of the nonwoven fabrics of examples 5 to 6 and comparative examples 5 to 6 are shown in Table 2.

TABLE 2

As can be seen from table 2, the meltblown nonwoven fabrics of examples 5 to 6 had more excellent tensile strength, hand and coefficient of friction, and were nonwoven fabrics having both higher strength and more excellent soft touch.