EP2639346A1

EP2639346A1 - Preparation method for ultrahigh molecular weight polyethylene fiber

Info

Publication number: EP2639346A1
Application number: EP11840013.4A
Authority: EP
Inventors: Chengsi Chen; Shian Xu
Original assignee: Ningbo Dacheng Advanced Material Co Ltd
Current assignee: Ningbo Dacheng Advanced Material Co Ltd
Priority date: 2010-11-08
Filing date: 2011-01-28
Publication date: 2013-09-18
Also published as: CN102002769A; CN102002769B; WO2012062053A1; EP2639346A4

Abstract

The invention discloses a preparation method with low energy consumption and low cost for high-strength and high-extension ultrahigh molecular weight polyethylene fiber. The method comprises two steps: firstly, preparing modified polyethylene master batch; and secondly, adding the prepared modified polyethylene master batch to a selected ultrahigh molecular weight polyethylene resin, uniformly mixing to prepare ultrahigh molecular weight polyethylene, and further performing melt spinning. The prepared ultrahigh molecular weight polyethylene fiber has fiber strength of 15CN/dtex-25CN/dtex and elongation at break of 5%-8%. The method disclosed by the invention has the advantages of short production flow, low energy consumption, environmentally friendly, low manufacturing cost, high standalone capacity and the like. The produced product can be widely used in the fields such as twist-knitting various ropes, braiding fishnets and weaving various industrial cloth, industrial belts and the like, and it can effectively retain high fiber strength while being used.

Description

Technical Field:

The invention discloses an innovative production method with low energy consumption and low cost for preparing high-strength and high -extension ultrahigh molecular weight polyethylene fiber from ultrahigh molecular weight polyethylene resin by adopting a melt spinning technology.

Background Arts:

Ultrahigh molecular weight polyethylene fiber having excellent performances such as high strength, low density, high modulus, high impact toughness, light resistance, good corrosion resistance and the like is regarded as a novel high-performance material, which is one of three current major types of high-tech fiber worldwide(carbon fiber, aramid fiber and ultrahigh-strength polyethylene fiber), and the products thereof can be widely used in the fields such as quartermaster equipment for national defense, aerospace, special composite materials, ocean engineering ropes, fishnets and the like. There are two classes of known production methods, as follows:

Class 1: the technologies is disclosed in Dutch patent NL7900990 , US patent US430577 , European patent EP0064167 and Chinese patents ZL85107352 , ZL97106768.6 , ZL03106030.7 , CN1995496A , CN101205633A , CN101205637A and other patent literatures, wherein all the technologies adopt a solution gel spinning method employing decalin, mineral oil, paraffin oil, pure white oil and kerosene as solvents, and the production process is performed in the following four steps:
1. 1. firstly adding ultrahigh molecular weight polyethylene resin into a solvent with a weight ratio of 5%-25%, heating, diluting and swelling, wherein the proportion of the solvent is 75%-95% (weight ratio), the swelling temperature is 90°C-110°C, and the swelling time is 1-2 hours;
2. 2. delivering the swelled ultrahigh molecular weight polyethylene solution into twin screws for melt extrusion spinning, quenching by chilled water to form gel as-spun fiber, winding the gel as-spun fiber and placing it in a barrel for storage;
3. 3. transmitting the gel as-spun fiber into an extraction agent, such as solvent naphtha, dimethylbenzene and methylene dichloride by using a traction machine, performing reverse transmission extraction at a certain speed, and completely extracting all the solvent in the gel fiber; and
4. 4. further performing drying, pre-drawing and ultra-drawing on the as-spun fiber after extraction by adopting a traction machine to prepare the fiber with high strength and high modulus. With regard to the fiber obtained by such technologies, the fiber strength is more than 30CN/dtex, and the modulus is more than 1000CN/dtex. Currently, the technologies are high in degree of industrialization and mature at home and abroad, however, they have the defects such as long production flow, high energy consumption, high material consumption, high manufacturing cost and the like.
Class 2: a technology for preparing high-strength polyethylene fiber by blending and melting of ultrahigh molecular weight polyethylene and low-density polyethyleneis disclosed in Chinese patent literature CN101230501A , wherein the ultrahigh molecular weight polyethylene selected has a molecular weight of 1.2 million-1.8 million and the low-density polyethylene has a molecular weight of 25,000-40,000, they are mixed with a mixing ratio of 10: 1, then twin screws are used for melt extrusion spinning, and the obtained fiber has a strength of 15-30g/D, a modulus of 400-1000g/D and elongation at break of 2.5%-3.5%. The technology selects the two raw materials having great difference in molecular weight distribution for mixing, which results in very small fiber elongation percentage (2.5%-3.5%) and great strength loss (the strength loss can be 30%-60%) and the like will occur if the fiber is used in the fields of multiple twisting for producing ropes, braiding of fishnets, weaving of industrial cloth and the like, and the fiber is further not suitable for applications in the fields of ropes, fishnets and the like.

Invention contents

Through long-term research and extensive experiments, the applicant invents ultrahigh molecular weight polyethylene fiber which can eliminate the defects of the above products and a method for preparing the same on the basis of the prior art.
According to the invention, the high-strength and high-extension polyethylene fiber is obtained by employing ultrahigh molecular weight polyethylene powder resin with a molecular weight of 1.5-2.5 million as a raw material, adding the modified polyethylene master batch with a weight ratio of 6%-10% and performing screw melt extrusion spinning and ultra-drawing, wherein the fiber strength is 15CN/dtex-25CN/dtex, and the elongation at break is 5%-8%.
The specific steps for preparing the ultrahigh molecular weight polyethylene fiber according to the invention are as follows:

Step 1: preparation of the modified polyethylene master batch:
1. (1) adding POE (polyolefin elastomer), a PE (polyethylene) blowing agent and ethylene-propylene-diene monomer (EPDM) or SEBS (styrene-ethylene-butylene-styrene) to LDPE (low-density polyethylene) or LLDPE (linear low-density polyethylene) selected as raw material, and mixing uniformly;
2. (2) performing twin-screw blending granulation on the uniformly mixed polymerto prepare the modified polyethylene master batch;
Step 2: preparation of ultrahigh molecular weight polyethylene melt spinning:
1. (1) adding the prepared modified polyethylene master batch to the selected ultrahigh molecular weight polyethylene resin, and mixing uniformly;
2. (2) feeding the mixture into a screw for extrusion melt spinning, cooling the fiber by a water bath and performing winding formation; and
3. (3) performing three-line ultra-drawing on the fiber formed by winding, drying and shaping to obtain finished fiber.

The ultrahigh molecular weight polyethylene fiber disclosed by the invention is most suitable for twist-knitting various ropes, braiding fishnets and weaving various industrial cloth and industrial belts, without generating strength loss. The method disclosed by the invention has the advantages of short production flow, low energy consumption, environmentally friendly, low manufacturing cost, high standalone capacity and the like and is an innovative technology in sustainable development of high-strength polyethylene industry. The invention has achieved a breakthrough in the technology forpreparing high strength and high extension fiber. The product can be widely used in the fields such as twist-knitting various ropes, braiding fishnets and weaving various industrial cloth, industrial belts and the like, and can effectively retain high fiber strength while being used.

Detailed Description:

According to the invention, ultrahigh molecular weight polyethylene powder resin with a molecular weight of 1.5-2.5 million is selected as a raw material, 6%-10% by weight of modified polyethylene master batch is added depending on the molecular weight of the polyethylene resin raw material, and the powder resin and the master batch are uniformly mixed, wherein 6% of the modified polyethylene master batch is added into the polyethylene resin with the molecular weight of 1.5 million, on this basis, the molecular weight of the polyethylene resin and the adding quantity of the modified polyethylene master batch increase according to a ratio of (0.1 million)/(0.4%), that is, when the molecular weight of the polyethylene resin is increased by 0.1 million, the adding quantity of the modified polyethylene master batch is increased by 0.4%, the process continues till the molecular weight of the polyethylene resin is increased to 2.5 million, and the adding quantity of the polyethylene modified master batch is increased to 10% at that time, for example, 7.2% of the modified polyethylene master batch is added into the polyethylene resin with the molecular weight of 1.8 million, 10% of the modified polyethylene master batch is added into the polyethylene resin with the molecular weight of 2.5 million, and so on; then a screw with an aspect ratio of 1: 40 is used for melt extrusion spinning and ultra-drawing so as to obtain the high-strength and high-extension polyethylene fiber with the elongation at break of 5-8% and the fiber strength of 15CN/dtex-25CN/dtex, wherein the fiber strength corresponds to the numerical value of the molecular weight of the ultrahigh molecular weight polyethylene resin, that is, the strength of the polyethylene fiber with the molecular weight of 1.5 million is 15CN/dtex, on this basis, the molecular weight of the polyethylene fiber and the numerical value of the strength thereof increase according to the ratio of (0.1 million)/(1CN/dtex), that is, when the molecular weight of the polyethylene fiber is increased by 0.1 million, the fiber strength is increased by 1CN/dtex, the process continues till the molecular weight of the polyethylene fiber is increased to 2.5 million, and the fiber strength is increased to 25CN/dtex at that time.
The specific steps for preparing the ultrahigh molecular weight polyethylene fiber according to the invention are as follows:

Step 1: preparation of the modified polyethylene master batch:
1. (1) adding 7%-15% by weight of POE (polyolefin elastomer), 3-5% by weight of a PE (polyethylene) blowing agent and 5%-10% by weight of ethylene-propylene-diene monomer (EPDM) or SEBS (styrene-ethylene-butylene-styrene) to LDPE (low-density polyethylene) or LLDPE (linear low-density polyethylene) selected as raw material, and mixing uniformly;
2. (2) performing twin-screw blending granulation on the uniformly mixed polymer to prepare the modified polyethylene master batch, wherein the temperature of each section of twin screws is in the range of 150°C-220°C, and the rotating speed of the twin screws is controlled at 200-250 revolutions per minute.

The prepared modified polyethylene master batch has excellent functions such as low melting point, low viscosity, good lubricating property, good flowability, easiness in dispersion and the like.

Step 2: preparation of ultrahigh molecular weight polyethylene melt spinning:
1. (1) adding 6-10% by weight of the modified polyethylene master batch prepared in step 1 to the selected ultrahigh molecular weight polyethylene resin with the molecular weight of 1.5-2.5 millionand mixing uniformly;
2. (2) feeding the mixture into a screw for extrusion melt spinning, wherein the aspect ratio of the screw is 1: 40, the temperature of each section of the screw is in a range of 150°C-250°C, the extrusion speed of the screw is 200-250 revolutions per minute, the spinneret plate has 100-150 pores, the pore diameter is 0.5-0.8mm, the temperature of a spun melt is controlled at 220°C-240°C, and the drawing speed of a spray head is 5-15m/minute; the sprayed as-spun fiber is cooled by a water bath, and the temperature of the water bath is controlled at 20°C-25°C; and the fiber cooled by the water bath is wound for forming; and
3. (3) performing three-line ultra-drawing and one-line drying and shaping on the fiber formed by winding to finally obtain finished fiber, wherein the first-line ultra-drawing uses a water bath for drawing, the temperature of the water bath is 80°C-95°C and the drawing ratio is 5-10 times; the second-line ultra-drawing uses superheated steam for drawing, the temperature of the steam is 110°C-130°C and the drawing ratio is 3-6 times; the third-line ultra-drawing adopts dry heating for drawing, the ultra-drawing temperature is 120°C-130°C and the drawing ratio is 1.1-1.2 times; the shaping temperature for drying and shaping is 130°C-145°C, and the shaping linear speed is 20-40m per minute; the ultrahigh molecular weight polyethylene finished product fiber is finally prepared; and winding is further performed.

The prepared polyethylene fiber has fiber strength of 15CN/dtex-25CN/dtex and elongation at break of 5%-8%.

Claims

Ultrahigh molecular weight polyethylene fiber, obtained by employing ultrahigh molecular weight polyethylene powder resin with a molecular weight of 1.5-2.5 million as a raw material, adding 6%-10% by weight of modified polyethylene master batch and performing screw melt extrusion spinning and ultra-drawing, wherein the fiber strength is 15CN/dtex-25CN/dtex, and the elongation at break is 5%-8%.
A method for processing the ultrahigh molecular weight polyethylene fiber according to claim 1, comprising the following specific steps:
step 1: preparation of modified polyethylene master batch:
(1) adding POE (polyolefin elastomer), a PE (polyethylene) blowing agent and ethylene-propylene-diene monomer (EPDM) or SEBS (styrene-ethylene-butylene-styrene) to an LDPE (low-density polyethylene) or LLDPE (linear low-density polyethylene) selected as a raw material, and mixing uniformly;

(2) performing twin-screw blending granulation on the uniformly mixed to prepare the modified polyethylene master batch;

step 2: preparation of ultrahigh molecular weight polyethylene melt spinning:
(1) adding the prepared modified polyethylene master batch to the selected ultrahigh molecular weight polyethylene resin, and mixing uniformly;

(2) feeding the mixture into a screw for extrusion melt spinning, cooling the fiber by a water bath and performing winding formation; and

(3) performing three-line ultra-drawing on the fiber formed by winding, drying and shaping to obtain finished fiber.
The method according to claim 2, characterized in that
in (1) of step 1, according to the weight ratio, the adding quantity of the POE is 7%-15%, the adding quantity of the PE bowing agent is 3%-5%, and the adding quantity of the EPDM or SEBS is 5%-10%;
in (2) of step 1, the temperature of each section of twin screws is between 150°C-220°C, and the rotating speed of the twin screws is controlled at 200-250 revolutions per minute;
in (1) of step 2, the ultrahigh molecular weight polyethylene resin with the molecular weight of 1.5-2.5 million is selected, 6%-10% by weight of the modified polyethylene master batch is added depending on the molecular weight of the polyethylene resin, and the resin and the master batch are uniformly mixed, wherein 6% of the modified polyethylene master batch is added into the polyethylene resin with the molecular weight of 1.5 million, on this basis, the molecular weight of the polyethylene resin and the adding quantity of the polyethylene modified master batch increase according to the ratio of (0.1 million)/(0.4%), that is, when the molecular weight of the polyethylene resin is increased by 0.1 million, the adding quantity of the modified polyethylene master batch is increased by 0.4%, the process continues till the molecular weight of the polyethylene resin is increased to 2.5 million, and the adding quantity of the polyethylene modified master batch is increased to 10% at that time;
in (2) of step 2, the aspect ratio of the screw is 1: 40, the temperature of each section of the screw is 150°C-250°C, the extrusion speed of the screw is 200-250 revolutions per minute, the spinneret plate has 100-150 pores, the pore diameter is 0.5-0.8mm, the temperature of a spun melt is controlled at 220°C-240°C, and the drawing speed of a spray head is 5-15m/minute; the sprayed as-spun fiber is cooled by a water bath, and the temperature of the water bath is controlled at 20°C-25°C; and the fiber cooled by the water bath is wound for forming;
and in (3) of step 2, the three-line ultra-drawing is performed, wherein the first-line ultra-drawing uses a water bath for drawing, the temperature of the water bath is 80°C-95°C and the drawing ratio is 5-10 times; the second-line ultra-drawing uses superheated steam for drawing, the temperature of the steam is 110°C-130°C and the drawing ratio is 3-6 times; the third-line ultra-drawing adopts dry heating for drawing, the dry heating temperature is 120°C-130°C and the drawing ratio is 1.1-1.2 times; as for drying and shaping, the shaping temperature is 130°C-145°C, and the shaping linear speed is 20-40m per minute; and the ultrahigh molecular weight polyethylene finished fiber is finally prepared, the elongation at break of the fiber is 5%-8%, and the fiber strength is 15CN/dtex-25CN/dtex, wherein the fiber strength corresponds to the numerical value of the molecular weight of the ultrahigh molecular weight polyethylene resin, that is, the strength of the polyethylene fiber with the molecular weight of 1.5 million is 15CN/dtex, on this basis, the molecular weight of the polyethylene fiber and the numerical value of the strength thereof are increased according to the ratio of (0.1 million)/(1CN/dtex), that is, when the molecular weight of the polyethylene fiber is increased by 0.1 million, the fiber strength is increased by 1CN/dtex, the process continues till the molecular weight of the polyethylene fiber is increased to 2.5 million, and the fiber strength is increased to 25CN/dtex at that time.