CN1027982C - Preparing process of fine denier and ultra-fine denier polypropylene fibre P - Google Patents

Abstract

This invention relates to fine and ultrafine denier polypropylene fibers and their manufacturing process. A variety of measures are adopted to stabilize the spinning process, such as controlling the spinning temperature between 200-280°C, selecting high-fluidity polypropylene with good thermal stability and spinning at a winding speed below 2000 m/min, and The high-strength draft of the winding yarn can be made into fine denier and ultra-fine denier polypropylene fibers with a single filament fineness of 0.2-2 denier, a tensile strength of 4-8 g/denier, and an elongation at break of 15-70%. The polypropylene resin for spinning fine denier yarns can be a chemically degraded resin with a narrow molecular weight distribution (Q<1.3), or a polypropylene resin composition with a fairly wide molecular weight distribution (molecular weight distribution index is 1.3-4.0).

Description

The present invention belongs to the manufacture method of polypropylene fiber.

The invention relates to the manufacturing technology of fine-denier polypropylene fiber and ultra-fine-denier polypropylene fiber.

Generally, chemical fibers with a single-filament fineness of about 1 denier are called fine-denier fibers, and chemical fibers with a single-filament fineness of about 0.5 denier are called ultra-fine denier fibers. This kind of fiber can be woven into high-grade textiles with soft hand feeling and comfortable wearing, and has high economic value. Therefore, the development of fine-denier fiber and ultra-fine-denier fiber manufacturing technology is a high-tech that all countries have paid attention to in recent years.

The diameter of fine-denier fiber and ultra-fine-denier fiber is much thinner than that of conventional chemical fiber (single filament size is generally about 3-6 denier), and the technical difficulty of manufacturing this type of chemical fiber is quite large - it is necessary to select appropriate spinning raw materials and auxiliary materials. In addition, it is also necessary to reasonably select the technical scheme of spinning and strictly control the production processes such as spinning and drafting. In recent years, the fine-denier fiber manufacturing technology of large varieties of chemical fibers such as polyester fiber and polyamide fiber has been successfully developed, and many commercial brands of fine-denier polyester and fine-denier polyamide fibers have been sold in various countries. However, the manufacturing technology of fine denier polypropylene fiber is still under development. From the patent reports published in recent years, it can be seen that the technical routes and product specifications for the development of fine denier polypropylene in various countries are different, and their common feature is that polypropylene resin with a relatively high melt flow index is used as the spinning material. special material. Some patents claim that the melt flow index of the special resin for fine denier yarn needs to be as high as 300-500 (measured according to ASTM D-1238 method, 230°C, 2.16kg). Some patents say that chemically degraded polypropylene resins with special specifications can be spun into fine denier fibers at relatively high spinning speeds, while other patents say that polypropylene resins with a high melt flow index can be spun into fibers Non-woven fabrics with a finer diameter (Ribita et al., JK, 1984, 59-94610; dry Sawa et al., JK, 1985, 60-17111; Ikeda et al., JK, 1988, 63-6107; Shikura et al., JK, 1988, 63-256714). Judging from the trend of new grades of fiber-grade polypropylene resin introduced abroad in recent years and some of the above-mentioned patent reports, many people believe that the manufacture of fine denier and ultra-fine denier polypropylene fibers requires that the raw material resin has good melt fluidity, Lower molecular weight and narrow molecular weight distribution ( Mw/ Mn<4). In addition, there are also individual patents saying that mixing polypropylenes with different molecular weights in a certain proportion can be used to make polypropylene fibers (R.L.Hudson, 1981, USP 4,296,022). In these patent reports, it is about how to use conventional melt spinning and drawing equipment to manufacture fine denier and ultrafine denier polypropylene fibers with excellent mechanical properties, and about which specification of polypropylene resin to use for spinning. Reports are still lacking. Therefore, the manufacturing technology of fine denier and ultrafine denier polypropylene fiber needs to be further developed.

The purpose of the present invention is to develop a new process for spinning polypropylene fine denier fibers and super fine denier fibers suitable for the existing general melt spinning equipment in my country and fine denier and super fine denier polypropylene fibers with excellent mechanical properties. The results of a large number of spinning experiments show that many commercial polypropylene resins cannot meet the requirements of "stable spinning" either because of their high impurity content and poor melt fluidity, or because of their molecular weight, molecular weight distribution, and isotacticity. The two basic requirements are the fine denier coiled yarn and the smooth drafting of it into a finished fiber with excellent mechanical properties. Generally speaking, the spinnability of polypropylene fine denier fibers is poor when using polymer grade isotactic polypropylene resins. Even those with fairly narrow molecular weight distribution ( Mw/ Mn is about 4-4.5), the molecular weight is small (about 160,000-170,000), and the melt fluidity is quite good for fiber-grade resins to be spun, and it is difficult to spin high-quality fine-denier polypropylene fibers smoothly, because If the spinning temperature of this type of resin is controlled below the temperature at which polypropylene degrades (the spinning temperature must be controlled below 270-280°C), the spun filaments will be very It is difficult to draw and cannot be made into fine-denier fibers with excellent mechanical properties. If the spinning temperature is raised above 270-280°C, polypropylene will degrade rapidly during the spinning process, and it is difficult to control fine-denier polypropylene fiber spinning. Process uniformity and long-term stability.

In recent decades, although great progress has been made in the research of blending and modifying polymers with different properties to make various new polymer materials, it is still difficult to develop materials by blending and modifying the same polymer with different specifications. The practice of new polymer materials seems to have not attracted enough attention. Whether the blending of different specifications of polypropylene can improve the spinning performance and performance of polypropylene fiber has not yet been unified.

During the process of developing the manufacturing technology of polypropylene fine and ultrafine fibers, we realized that the spinnability of polymer grade polypropylene resins made with various catalysts to spin fine fibers or ultrafine fibers cannot be achieved. satisfactory. Although the high-fluidity polypropylene resin made by modifying the polymerization-grade polypropylene produced by conventional catalysts by controlled chemical degradation can improve the spinnability of fine denier yarns, the effect is still not ideal (it should be pointed out that Many published research reports on fine-denier polypropylene manufacturing technology often use this type of polypropylene resin as spinning raw material). Through a large number of comparative experiments, we found that the polymer-grade polypropylene resin made with a carrier-type high-efficiency catalyst was chemically degraded and modified, and the resin with a higher melt flow index and a narrower molecular weight distribution was better than the first two polypropylene resins. The resin has good spinning performance (the MI of this resin is about 40, the molecular weight distribution index Q is 1.1-1.5, and the Q value is determined by the method suggested by Zhao Delu et al., Polymer Communications, (3), 234, 1983,) . And the spinning performance of the polypropylene resin composition having the molecular weight and the molecular weight distribution varied widely by polymer grade polypropylene and chemically degraded polypropylene is also very good. On the basis of a large number of spinning contrast experiments, we have invented a A new process for stable spinning of ultrafine denier polypropylene fiber.

Basic design and main technology of the present invention constitute as follows:

The purpose of the present invention is to provide a new stable spinning process with good spinning effect for the technical difficulties in the manufacture of polypropylene fine denier fibers and ultrafine denier fibers, and the fine denier and ultrafine denier fibers produced by this method. Denier polypropylene fiber products. It is characterized by trying to reduce the fluctuation of various process parameters in the spinning process, suppressing the unstable factors in the polypropylene fiber manufacturing process as much as possible, so that the high-strength drawing process of the spinning melt and fine denier winding yarn can be continued It goes on and on and on. In order to suppress the inhomogeneity of melt viscosity caused by the degradation of polypropylene in the spinning process and make the polypropylene resin fully melt and uniform during spinning, the melt temperature of polypropylene during spinning should be controlled below 280°C and Above 200°C, preferably between 260°C and 220°C. The selected polypropylene resin should have good thermal stability, that is, it is necessary to add a sufficient amount of stabilizer to the polypropylene resin without a degradation accelerator, so as to inhibit excessive thermal degradation of the polypropylene melt during the spinning process And chemical degradation makes the spinning process difficult to carry out stably. The selected polypropylene resin should also have fairly good melt fluidity and stretchability, and its melt flow index should be controlled between 12-100. This high-fluidity polypropylene resin can be a chemically degraded polypropylene resin with a narrow molecular weight distribution, and its molecular weight distribution index Q value ranges from 1.2 to 1.8. Degradation of modified raw materials. That is to say, the polypropylene resin special material for spinning fine denier fibers needs to be produced by controlled degradation of the polymer grade polypropylene produced by the carrier-type high-efficiency catalyst with a chemical degradation agent. However, it is also possible to use a polypropylene resin composition with good melt fluidity and a wide molecular weight distribution (the control range of the melt flow index is between 12-100, and the control range of the molecular weight distribution index Q value is between 1.3-4.0 ) as a special spinning material for spinning fine denier fibers and ultrafine denier fibers.

Polypropylene fiber is usually colored by the dope coloring method, and the colorant used in spinning is usually mixed with polypropylene resin in the form of color masterbatch for spinning. This can also be done in the manufacture of polypropylene fine denier fibers and ultrafine fibers, but it is best to choose a suitable color masterbatch, mix it with polypropylene resin, and mix and granulate it to make uniform colored chips. Spinning with colored chips can reduce the color difference of polypropylene fine denier fibers and ultrafine fibers and improve their spinning and drawing properties.

The invention is a stable spinning process suitable for general melt spinning equipment. The range of the winding speed selected is 300-1500 m/min, and the hot drawing temperature range of the winding wire is 50-160°C. The thermal drafting of winding yarn depends on the raw materials selected for spinning, spinning conditions and the requirements for finished fibers. The drafting ratio can generally be controlled between 2.5-6 times, preferably 3-4 times. about.

The method of the present invention can be spun into coiled filaments with a monofilament fineness of 7-0.9 denier, and can be made into finished fibers with a monofilament fineness of 2-0.2 denier through hot drawing. The tensile strength of the finished fiber is 4-8 g/denier, and the elongation at break is 15-70%.

The present invention intends to briefly illustrate the advantages and characteristics of the present invention through the following examples and comparative examples. It should be noted, however, that the present invention cannot be considered limited to the contents of the Examples.

Example 1

Select the polypropylene resin composition (MI=26, Q=2.0) of the following formula (see Table 1) for melt spinning, the spinning temperature needs to make the resin fully melted and uniform (controlled at 260°C), and the winding speed is 400 meters /min is wound into silk, and the monofilament fineness of the spun wound silk is 3.6 denier and 1.7 denier respectively. They were respectively drawn into finished fibers with a monofilament fineness of 1.1 denier and 0.56 denier by hot drawing. The tensile strength of the finished fiber is 5.3 g/denier and 5.7 g/denier respectively, and the elongation at break 70% and 25%. Under the same (or similar) spinning and drawing conditions, the polymer grade polypropylene resin (commonly known as fiber grade polypropylene resin, MI=12.8 g/denier, Q=1.43, Mw/ Mn≈4-4.5) Although it can be wound into filaments, it cannot be drawn smoothly and cannot be made into finished fibers with good mechanical properties.

Table 1 The formula of polypropylene resin composition

Support type high-efficiency catalysis

Polymer grade polypropylene (MI=12.8, Q=1.43) 50 parts

Chemically degraded modified polypropylene (MI=43, Q=1.27) 50 parts

Calcium stearate 0.1 part

2,6-di-tert-butyl-4-methylphenol (BHT) 0.2 parts

Irganox 1010 0.2 parts

(Tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester)

HALS Tin 944 (Ciba-Geigy) 0.2 parts

Example 2

The polypropylene resin compositions of the following three formulations (see Table 2-1) were selected for melt spinning, the spinning temperature was 260°C, and the winding speed was 400 m/min. These three kinds of polypropylene resins can all be successfully spun into winding yarns with a monofilament fineness of about 1.7 denier, and can be smoothly drawn into finished fibers with a monofilament fineness of <0.6 denier. The maximum draw ratios of these wound filaments and the mechanical properties of the finished fibers are listed in Table 2-2.

Table 2-1 Formula of polypropylene resin composition*

No. Supported high-efficiency catalytic polymerization grade polypropylene chemically degraded modified polypropylene

(MI=12.8, Q=1.43) (MI=43, Q=1.27)

2-1 90 copies 10 copies

2-2 80 copies 20 copies

2-3 70 copies 30 copies

* Other processing aids added in this series of polypropylene resin compositions are the same as those in Example 1.

Table 2-2 Properties of polypropylene winding yarn and finished yarn

Properties of the most finished fibers of polypropylene tree wound filaments

Grease number Maximum draft multiple

Monofilament Denier Tensile Strength Elongation at Break

(denier) (gram/denier) (%)

2-1 4.5 0.54 5.9 50

2-2 4.5 0.60 5.9 30

2-3 4.4 0.55 5.2 20

Example 3

It is made of high-viscosity polymer grade polypropylene (MI=1.4) and high fluidity chemical degradation The polypropylene resin composition made of polypropylene is a special material for spinning (see Table 3-1 for the formulation of this series of polypropylene compositions), and it is spun at a spinning temperature of 230-260°C, at a rate of 400 m/ The winding speed is divided into filaments. The spun winding yarns can be smoothly drawn into fine denier yarns, and the specifications of the finished yarns are listed in Table 3-2. The result of the spinning comparison experiment shows that the spinnability of the polymer grade polypropylene resin is obviously lower than that of the polypropylene resin composition selected in the present invention. For example, if the spinning temperature of a polymer grade resin with a melt flow index of 1.4 is gradually increased from 230°C to 280°C, it cannot be spun smoothly; while the aforementioned high-efficiency catalytic polymerization grade polypropylene resin (fiber grade resin) although the molecular weight The distribution is narrow (Q=1.43), and it can be wound into filaments, but it is difficult to draw, and its mechanical properties are far from reaching the very wide molecular weight distribution of the present invention (Q=2.8) and the melt flow index is similar to it (MI =12) The quality index of the fine denier fiber spun from the polypropylene resin composition (see Table 3-1 and 3-2).

Table 3-1 Formula of polypropylene resin composition*

Polypropylene Polymerization Grade Polypropylene Chemical Degradation Modified Polypropylene Resin Composition

Resin Propylene Component Polypropylene Component

Number (MI=1.4, Q=1.3) (MI=43, Q=1.27) MI Q

3-1 2 parts 98 parts 45 1.3

3-2 5 parts 95 parts 35 1.4

3-3 10 parts 90 parts 30 1.45

3-4 50 parts 50 parts 12 2.8

*The other additives added in this series of polypropylene resin compositions are the same as those in Example 1.

Table 3-2 Properties of polypropylene winding yarn and finished yarn

Polypropylene tree Spinning temperature Winding yarn Properties of finished fiber

Fat No. Degree (℃) Denier

(Dan) Monofilament Denier Tensile Strength Elongation at Break

(denier) (gram/denier) (%)

3-1 235 2.4 0.67 5.4 15

3-2 255 1.7 0.43 7.8 21

3-3 235 2.5 - - - -

3-4 260 2.4 0.82 5.6 75

3-4 260 1.7 0.53 5.7 80

Example 4

The polymer grade polypropylene produced by the carrier-type high-efficiency catalyst is selected as the raw material, and the high-fluidity polypropylene resin (MI=43, Q=1.27 is made by organic peroxide controlled degradation treatment, and a sufficient amount of Stabilizers, flow improvers and other additives). This chemically modified high-fluidity polypropylene resin is used for spinning, the spinning temperature is 235 °C, the winding speed is 400 m/min, and it is spun into winding yarn with a single fiber fineness of 1.8 denier, and then heated The fine denier fiber of 0.53 denier is made by drafting. The finished yarn had a tensile strength of 8.0 g/denier and an elongation at break of 25%.

Example 5

Select No. 3-2 polypropylene resin composition used in the embodiment of the present invention 3 as spinning The material is spun at 230°C, and the winding speeds are 500, 600, 800 and 1000 m/min, respectively, and wound into coiled filaments with single filament deniers of 4.5, 4.2, 2.8 and 2.2 deniers respectively. All the yarns have good drawing performance, and the maximum drawing ratios are 6.4, 5.7, 5.3 and 4.8 times respectively.

Example 6

In order to manufacture dope-colored polypropylene fine denier fibers, the No. 3-2 polypropylene resin composition used in Example 3 of the present invention was selected as the raw material resin for spinning. Mix 100 parts of resin with 2 parts of yellow masterbatch, 2 parts of red masterbatch and 2 parts of blue masterbatch respectively to make colored polypropylene chips. These colored chips can all be spun into winding yarns with a single fiber size of 2.1-6.9 denier at a spinning temperature of 245° C. and a winding speed of 400 m/min. These winding yarns all have good drawability. The maximum draft ratios are 4.4-6.5 times respectively (see Table 4 for details)

Table 4

Polypropylene resin Monofilament fineness of winding yarn Maximum draft ratio

(dawn)

Yellow polypropylene resin 6.9 6.1

Composition 4.3 5.6

3.2 5.1

2.1 4.9

Red polypropylene resin 6.9 6.1

Composition 3.5 5.0

2.1 4.4

Blue polypropylene resin 6.9 6.5

Composition 2.1 4.7

Claims (5)

1, the manufacture method of thin dawn and superfine denier polypropylene fibers, it is characterized in that using the spinning PP Pipe Compound, the melt temperature of spinning PP Pipe Compound is 200-280 ℃ during spinning, wire winding speed be 300-1500 rice/minute, making filament number is the thin dawn undrawn yarn at 0.9-7 dawn, and thin dawn undrawn yarn is carried out hot drawing-off, and hot drawing temperature is 50-160 ℃, drafting multiple is 2.5-6 times, and making filament number is the thin dawn and the superfine denier polypropylene fibers at 0.2-2 dawn.

2, the manufacture method of thin dawn as claimed in claim 1 and superfine denier polypropylene fibers, the spinning PP Pipe Compound of using is the polypropylene resin composite that chemical degradation polypropylene, polymer grade polypropylene and processing aid (comprising stabilizing agent, flow improving agent, antistatic additive etc.) with high fluidity combine, its melt flow index is that 12-100(is preferably 30-50), polyacrylic molecular weight distributing index Q value is 1.3-4.0.

3, the manufacture method of thin dawn as claimed in claim 1 and superfine denier polypropylene fibers, the spinning PP Pipe Compound of using is the polypropylene resin composite made from chemical degradation of polypropylene resin and processing aid (comprising stabilizing agent, flow improving agent, antistatic additive etc.), its melt flow index is that 30-100(is preferably 30-50), polyacrylic molecular weight distributing index Q value is 1.1-1.5, used chemical degradation of polypropylene resin is to be raw material with the efficient catalytic polymer grade polypropylene resin, it is carried out chemical degradation and gets with a certain amount of organic peroxide.

4, the manufacture method of thin dawn as claimed in claim 1 and superfine denier polypropylene fibers, its thin dawn and superfine denier polypropylene fibers are to use as claim 2 or the described spinning PP Pipe Compound of claim 3, filament number is the 0.2-2 dawn, tensile strength is the 4-8 gram/dawn, elongation at break is 15-70%, the melt flow index of this polypropylene fibre is 12-100, and polyacrylic molecular weight distributing index Q value is 1.1-4.0.

5, the manufacture method of thin dawn as claimed in claim 1 and superfine denier polypropylene fibers, used spinning PP Pipe Compound is the polypropylene resin composite that is mixed with colouring agent, it is to form with the spinning PP Pipe Compound mixing granulation described in polypropylene Masterbatch and claim 2 or the claim 3, the filament number of making thin dawn and superfine denier polypropylene fibers is the 0.2-2 dawn, tensile strength is the 4-8 gram/dawn, and elongation at break is 15-70%.