CN-119192734-B - Production process of special material for random copolymerization soft fiber high-end sanitary material

CN119192734BCN 119192734 BCN119192734 BCN 119192734BCN-119192734-B

Abstract

The invention provides a production process of a special material for random copolymerization soft fiber high-end sanitary materials, which mainly solves the problems of thicker wire drawing, more burrs of products and poor softness of the conventional gas phase method homo-polymerization polypropylene materials. The preparation method is characterized by comprising the following steps of S1, prepolymerizing a catalyst and propylene to generate a prepolymerized product, S2, carrying out random copolymerization on the generated prepolymerized product, gas-phase propylene and a small amount of ethylene under the action of the catalyst, obtaining polymer base powder under the polymerization process condition, and S3, carrying out peroxide degradation reaction, namely blending the obtained polymer base powder with an additive, degrading the polymer base powder by an oxide degradation agent, and carrying out melt extrusion granulation to obtain the target product. The special material non-woven fabric product has good softness, and the diameter of the filaments is finer and more uniform, so that the product has more excellent hand feeling.

Inventors

WANG BAOJIE
XIN GONGHUA
WANG GUIYAN
LI YANAN
LI YANG
LU DECHENG
SUN GANG
LIU WEIZHONG
LIU SU

Assignees

中国石油天然气股份有限公司

Dates

Publication Date: 20260505
Application Date: 20230625

Claims (7)

1. A production process of a special material for random copolymerization soft fiber high-end sanitary materials is characterized by comprising the following steps: first step, prepolymerization Prepolymerizing the catalyst with propylene to produce a prepolymerized product under prepolymerization conditions; Second step, random copolymerization Under the action of a catalyst, carrying out random copolymerization reaction on the generated prepolymerization product, gas-phase propylene and ethylene, and obtaining polymer base powder under the polymerization process condition; Third step, peroxide degradation reaction Blending the obtained polymer base powder with an additive, degrading by a peroxide degradation agent, regulating the melt index of the product, and carrying out melt extrusion granulation to obtain a target product; The catalyst in the step 1 and the step 2 is prepared from a main catalyst, a cocatalyst and an electron donor, wherein the main catalyst is ZN118 and/or CS2, the cocatalyst is triethylaluminum, and the electron donor is DonorC; The polymerization process conditions of the random copolymerization reaction in the step 2 are that the temperature is 70-75 ℃, the pressure is 2.7-3.0 MPa, the residence time is 1 hour and 20 minutes, the ratio of a cocatalyst to a main catalyst is 3-5:1, the ratio of the cocatalyst to an electron donor is 2-10:1, the mass percent of polymerized ethylene is controlled between 2.0-3.0%, and a multi-zone circulating reactor is added with hydrogen to adjust the molecular weight, so that the melt index of random copolymerization polypropylene powder generated in the reactor is ensured to be 7.0-10.0g/10min; The additive in the step 3 is a composite antioxidant, the composite antioxidant is an antioxidant compounded by B215 and calcium stearate, the adding amount is 1000ppm-2000ppm, and the added degradation agent is peroxide 2, 5-dimethyl-2, 5-bis (tert-butyl peroxide) hexane.
2. The production process of the special material for the random copolymerization soft fiber high-end sanitary material, which is disclosed in claim 1, is characterized in that in the step 1 and the step 2, the proportion of a main catalyst ZN118 to CS2 is 1:1, the proportion of a cocatalyst to the main catalyst is 3-5:1, and the proportion of the cocatalyst to an electron donor is 2-10:1.
3. The process for producing the special material for the random copolymerization soft fiber high-end sanitary material, which is disclosed in claim 1, is characterized in that the catalyst for the prepolymerization is prepared by mixing the catalyst and grease together under the protection of nitrogen, entering a prepolymerization reactor after being precontacted at 15 ℃, and carrying out the prepolymerization reaction with propylene entering through an online mixer, wherein the grease component is a mixture obtained by mixing white oil and vaseline in a volume ratio of 2:1.
4. The process for producing the special material for the random copolymerization soft fiber high-end sanitary material, which is disclosed in claim 1, is characterized in that the process condition of the prepolymerization is that the prepolymerization is carried out in a propylene liquid phase body environment, the prepolymerization is carried out in a small loop at a temperature of 25-30 ℃ and a pressure of 2.8-3.2 Mpa, and the residence time is 10-20 minutes.
5. The production process of the special random copolymerization soft fiber high-end sanitary material according to claim 1, wherein the additive in the step 3 is a single agent, and the single agent is respectively prepared by compounding IRGANOX 1010, IRGAFOS 168 and calcium stearate according to a mass ratio of 1:2:2.
6. The process for producing the special material for the random copolymerization soft fiber high-end sanitary material, which is disclosed in claim 1, is characterized in that the melt index of the target product granules produced in the step 3 is 35.0-40.0g/10min.
7. The production process of the random copolymerization soft fiber high-end sanitary material special for the infant diaper is characterized in that the target product generated in the step 3 is used for preparing a non-woven fabric high-end sanitary material, and the non-woven fabric Gao Duanwei is a baby diaper, a senile diaper and an operation suit.

Description

Production process of special material for random copolymerization soft fiber high-end sanitary material Technical Field The invention relates to the field of olefin polymerization, in particular to a production process of a special material for high-end sanitary materials of random copolymerization soft fibers. Background The method for producing the PP special for the high-fluidity non-woven fabric by the industrial gas phase method mainly comprises a hydrogen regulating method and a degradation method (also called as a controllable rheological method). The hydrogen regulating process is to add a certain amount of hydrogen in propylene polymerization process to regulate the relative molecular mass and distribution of polypropylene and produce polypropylene with relatively high melt flow rate, and the degradation process is to polymerize propylene into powder with relatively low melt flow rate, then add liquid or solid peroxide to degrade, extrude and granulate to obtain polypropylene product with relatively high melt flow rate and narrow relative molecular mass distribution. After the polypropylene base powder is degraded, the distribution of the molecular weight of the polypropylene becomes narrower, and the spinnability of the fiber material is enhanced. Therefore, when the special material for producing the fiber-grade high-melt-flow-rate polypropylene by the gas phase method, the degradation method is adopted, and the degradation of the homo-polypropylene by peroxide is adopted. When the non-woven fabric is processed, the spun yarn is thicker, the softness of the product is insufficient, and auxiliary materials such as a softening agent and the like are required to be added to improve the processing performance and the service performance. At present, raw materials of domestic gas-phase method non-woven fabrics high-end guard (baby diaper, senile diaper, operating gown and operating room supplies) adopt polypropylene homo-polymerization products, produced filaments are thicker, the drawing diameter can only reach about 2 denier, the softness of the product can not meet the requirements, and the manufactured sanitary material has the phenomenon of burrs, stimulates the skin and influences the hand feeling. The invention solves the defects of thicker wire drawing, more burrs of products, poor softness and the like of the gas phase method homopolymerized polypropylene material. Disclosure of Invention The invention aims to solve the technical problems of thicker wire drawing, more burrs and poor softness of products of the conventional gas phase method homopolymerized polypropylene material in the background art, and provides a production process of a special material for random copolymerization soft fiber high-end sanitary materials, wherein the special material for random copolymerization soft fiber high-end sanitary materials has good softness, which is higher than that of the conventional homopolymerized products by more than 15%; meanwhile, the diameter of the yarn is finer and more uniform, the problem of burrs is solved, and the hand feeling of the product is more excellent. The invention solves the problems by the following technical proposal that the production process of the special material for the random copolymerization soft fiber high-end sanitary material comprises the following steps: first step, prepolymerization Prepolymerizing the catalyst with propylene to produce a prepolymerized product under prepolymerization conditions; Second step, random copolymerization Under the action of a catalyst, carrying out random copolymerization reaction on the generated prepolymerization product, gas-phase propylene and ethylene, and obtaining polymer base powder under the polymerization process condition; Third step, peroxide degradation reaction And blending the obtained polymer base powder with an additive, degrading by an oxide degradation agent, regulating and controlling the melt index of the product, and carrying out melt extrusion granulation to obtain the target product. Further, the catalyst in the step 1 and the step 2 is configured by a main catalyst, a cocatalyst and an electron donor, wherein the main catalyst is ZN118 and/or CS2, the cocatalyst is triethylaluminum, and the electron donor is DonorC. Further, in the step1 and the step 2, the ratio of the main catalyst ZN118 to CS2 is 1:1, the ratio of the cocatalyst to the catalyst is 3-5:1, and the ratio of the cocatalyst to the electron donor is 2-10:1. Further, the preparation of the catalyst for the prepolymerization reaction is to mix the catalyst with grease under the protection of nitrogen, enter the prepolymerization reactor after being precontacted at 15 ℃ and carry out the prepolymerization reaction with propylene entering through an online mixer, wherein the grease component is a mixture obtained by mixing white oil and vaseline in a volume ratio of 2:1. Further, the pre-polymerization reaction is carried out in the liquid phas