Low-odor high-transparency ultrahigh flowability polypropylene as well as preparation device and method thereof

Abstract

The invention discloses low-odor high-transparency ultrahigh flowability polypropylene which comprises the following components in percentage by mass: 96-99.89% of a polypropylene resin, 0.1-2% of a free radical form initiator, 0-0.2% of a lubricant, 0.01-0.3% of an antioxidant and 0-1.5% of a compounded transparent nucleating agent. Due to adoption of the compounded transparent nucleating agent which is sufficiently reacted with the polypropylene resin, the initiator, the lubricant and the antioxidant synergistically, the ultrahigh flowability polypropylene which is high in transparency, lowin yellow index and low in haze is prepared. In addition, the invention further discloses a completely novel preparation device and process of the low-odor high-transparency ultrahigh flowability polypropylene. The transparency, the low odor and the low volatilization of the product in the preparation process can be further improved on the basis of a completely novel formula, the product can be prepared by using a one-step method, large-scale popularization and production in factories can be implemented, meanwhile, the problem of small molecule residues in the product is also solved to a largeextent, and aftertreatment processes of non-woven fabric manufacturing companies can be simplified.

Description

technical field [0001] The invention belongs to the technical field of modified plastics, and relates to a low-odor, high-transparency, super-fluidity polypropylene and a preparation device and method thereof. Background technique [0002] Ultra-high fluidity polypropylene generally refers to a polypropylene material with a very high melt index (MI≥500g / 10min), which is often used as the main material for non-woven fabrics in the melt-blown process. At present, there are generally three processes for preparing ultra-high fluidity polypropylene. One is the hydrogen control process in the polymerization process (that is, the hydrogen adjustment method). The polypropylene melt index prepared by this process has a limited range of adjustment, and it is difficult to adjust to a high level, and the molecular weight distribution is usually wide, which is not conducive to melt-blowing. The production and product performance of textiles; one is the synthesis of ultra-high fluidity p...

AI Technical Summary

Problems solved by technology

In the prior art, the ultra-high fluidity polypropylene products produced through the degradation of polypropylene by peroxide free radical initiators contain more initiator residues and small molecule by-products formed by free radical degradation reactions, resulting in product degradation. The content of volatile organic compounds (VOC) is high, and the odor level generally exceeds the hygienic requirements of the industry. Respiratory protective equipment carrying a large amount of organic small molecules and aromatic substances is bound to be inhaled into the body during use by consumers. affect the health of

With the diversification and high-end trend of people's aesthetic pursuit, the market demand for high-transparency non-woven products is developing rapidly. The demand is increasing, and the ultra-high fluidity polypropylene products produced by the existing technology often have poor transparency and high haze, which affects the promotion and use of non-woven fabrics in these fields

[0004] Chinese patent document CN103571039B discloses a high melting index polypropylene composition and a preparation method thereof, which is prepared by blending and extruding polypropylene, peroxide masterbatches, and nucleating agent masterbatches in a twin-screw extruder for melt granulation High-melting index, high-performance polypropylene resin, but this method needs to go through twin-screw granulation three times in order to obtain the final product material, which requires high energy consumption, time-consuming and laborious

Chinese patent CN1314745C discloses a high-flowability polypropylene manufacturing method, adding powdered polypropylene and a peroxide chemical degradation agent into a stirred reactor to prepare a polypropylene with a melt index of 40-3000g / 10min through solid-phase degradation reaction. Polypropylene, but the product obtained by this method has poor controllability of melt index, wide molecular weight distribution, and more residual chemical degradation agents

At present, most of the transparent nucleating agents used in the prior art are sorbitol or organic phosphates or abietic acid salts, etc., but they are generally used alone, and it is difficult to combine high transparency and low Odor, high melting index, low ash and other characteristics

The dispersibility of sorbitol-based transparent nucleating agents tends to be poor when used alone (melt-type nucleating agents rely on melting and dispersing into the matrix resin after reaching their melting point, but this type of nucleating agent usually has a higher melting point. It is difficult to completely melt at the processing temperature), the smell is large (contains a small amount of free aldehyde, mainly the residual aldehyde in the production process of sorbitol acetal and the aldehyde produced in the resin processing process) and poor heat resistance (through the acetal The chemical structure of the sorbitol transparent nucleating agent prepared by chemical reaction is poor in heat resistance); the products using the organic phosphate transparent nucleating agent are often difficult to disperse in the PP resin matrix because of their high melting point. And the single use of organic phosphates will cause higher ash content in the product, which will affect the production and processing technology of melt-spun non-woven fabrics; the products using rosin salts transparent nucleating agent alone will have low fluidity and poor dispersion effect. Poor resulting in less than ideal transparency

Therefore, the transparent nucleating agent used alone in the prior art lacks the dispersion uniformity of the transparent agent in PP, and it is difficult to effectively ensure its transparency while ensuring the flow performance, which will also have a corresponding impact on the mechanical properties of polypropylene. Adverse effects, such as increased brittleness, reduced aging resistance

Accordingly, for polypropylene materials, the influence of its components on transparency, odor control, fluidity, and mechanical properties makes it a relatively complex synergistic system, because the nucleation speed of different types of nucleating agents is Different, inappropriate use of nucleating agents is likely to be counterproductive and cause defects in other aspects of the resin. In the prior art, there is no polypropylene product that can maintain the above multiple advantages at the same time

Images