Research on the Mechanism and Classification of Internal and External Lubricants in Plastic Processing

Introduction: Background and Significance of Plastic Lubricants Development

In the contemporary development process of the plastic industry, lubricants serve as important processing aids, with an application history dating back to the mid-20th century. With rapid advancements in polymer material processing technology, especially with the widespread use of efficient processing equipment such as extrusion and injection molding, higher demands have been placed on lubrication performance during plastic processing. Lubricants not only significantly improve production efficiency and reduce energy consumption but also enhance product surface smoothness while minimizing defects; they are one of the key factors ensuring product quality.

Traditional lubrication theory is primarily based on the fundamental principle of "polar similarity compatibility," which posits that the degree of polarity matching between lubricant molecules and resin matrices determines their lubrication performance. However, modern research indicates that the actual mechanisms by which lubricants operate are far more complex than this simple principle suggests. Factors such as functional group types within lubricant molecules, spatial configuration, molecular weight distribution, and processing conditions can all significantly impact final lubrication effectiveness. This complexity means that lubricant selection and application still largely depend on empirical knowledge.

Chapter 1: Study on Mechanisms of Plastic Lubricants

1.1 Mechanisms and Performance Characteristics of External Lubricants External lubricants typically refer to organic compounds where non-polar portions dominate their molecular structure. These substances exhibit lower surface tension with poor compatibility with polar resins; thus they tend to migrate to system interfaces during processing. Analyzing from a molecular perspective, external lubricating actions can be divided into two critical stages: before resin plastification occurs, external lubricant molecules physically adsorb onto resin particle surfaces forming isolation layers that effectively reduce inter-particle friction coefficients; during melting plastification phases, external lubricants mainly form a lubricating interface between melt materials and metal surfaces in processing equipment to minimize adhesion phenomena.

It is noteworthy that there are significant differences in performance among different types of external lubricants. Traditional non-polar external lubricants (such as paraffin) create weaker lubrication films prone to failure under high-temperature shear conditions. In contrast, those containing moderately polar groups (like lead stearate) demonstrate superior properties due to their ability to form coordination bonds through polar groups interacting with either resin molecules or metal surfaces—significantly enhancing interfacial bonding strength. Oxidized polyethylene wax (OPE wax) exemplifies these improved external lubricators; its carboxyl groups interact both with metal surfaces as well as polar groups within resins for notable enhancement in lubrication effects.

1.2 Mechanisms & Influencing Factors for Internal Lubrication Agents Internal lubes generally consist small-molecule compounds rich in strong polar functional groups whose operating mechanisms fundamentally differ from those found within exterior agents' functionality characteristics From a kinetic viewpoint regarding molecule movement dynamics internal lube particles infiltrate amidst chains comprising resin structures performing via two primary methods: firstly reversible coordination bonds formed by interactions between respective functional units alongside corresponding polymers yielding dynamic equilibrium reducing friction across segments Secondly steric hindrance induced through long-chain nonpolar sections promoting relative slippage amongst chains further optimizing flow characteristics The efficacy associated internal agents relies heavily upon three pivotal parameters namely polarity intensity melt viscosity melting point Amongst these indicators polarity serves core metric directly determining interaction strengths existing agent versus target matrix For instance common fatty acid esters function exceptionally compatible PVC-like resins maintaining stable operational performances elevated temperatures Comparatively although paraffinic materials showcase ideal thermal thresholds viscosities lacking requisite polarization limits reliance solely van der Waals forces often leads failures extreme heat levels underscoring significance related functionalities throughout processes involved .

Chapter 2: Systematic Classification Of Plastics’Lubrics

2..1 Classifications Based On Operating Principles: According exhibited various roles manifested throughout manufacturing procedures distinct classes emerge encompassing three principal categories interior-oriented formulations typified chiefly fatty-acid-esters alcohols focusing reduction intrinsic frictions present respectively Whereas outer-lubing products including metallic soaps higher fatty acids improving interactions observed melts against apparatus constituents Compounding mixtures represent crucial developmental trajectory recent years whereby multifaceted designs consolidate diverse functionalities singularly embodied like calcium-stearates demonstrating duality features spanning both inner/outer functions [3]This classification method advantageously reflects practical applications aiding operators selecting tailored solutions according specific requirements Nevertheless limitations persist many instances wherein actual workings simultaneously embody aspects relating internally externally hence merely differing emphases highlighted Example certain ester compositions reveal predominant outward functioning at low temps transitioning inward influences amid heightened shearing environments [4] 2..2 Chemical Structure-Based Classifications: Viewed structurally analyzing composition plastics-based additives yields seven overarching categories Hydrocarbon variants command substantial market share owing cost-effectiveness stability covering everything ranging liquid-paraffin derived synthetic polyethylenes Fatty-acids represented best known variant Stearic-Acid possessing unique hydrogen-bonded configurations imparting temperature-dependent behaviors Alcohol derivatives maintain excellent compatibilities prevalent transparent productions Similarly amides gain traction engineering thermoplastics exhibiting favorable release qualities Esters remain dominant type widely utilized modulating ratios allow precise control compatibilities across varied substrates Metal-soaps retain traditional relevance albeit facing competition newer compound varieties reflecting integrated multi-functional prospects driving forward innovations within sector[5]\r ### Chapter 3 : Analysis Of Typical Properties Found Within Commonly Used Additives 3..1 Performance Traits Associated Hydrocarbons Applications: Representing oldest category hydrocarbons comprise entirely carbon-hydrogen entities showcasing minimal polars Thus predominantly manifest inner-lubry properties vis-a-vis nonpolars e.g PE PP Conversely when interfacing PVC counterparts lean towards externals Polythylene-wax possesses advantageous traits akin general-purpose plastics rendering optimal choices across polyolefin workflows [6]Oxidized Polyethylene-Waxes notably address conventional limitations witnessed previous iterations facilitating robust adherence achieved metals whilst concurrently fostering moderate engagements respective reactive-resin counterparts thereby expanding applicability horizons Actual deployments usually restrict OPE concentrations maintained around percent threshold excess may provoke frosting anomalies observed atop finished goods [7]\r 3..2 Unique Attributes Exhibited By Fatty Acids Derivatives: Hard-Fatty Acid ranks most frequently employed representative offering distinctive characteristic profiles At ambient temperatures hydrogen-bonds enable dimerization establishing associative frameworks enabling pronounced exteriors When heated beyond designated ranges(typically exceeding degrees Celsius )bond ruptures liberating free-flow components initiating interiorized enhancements Hence temperature-responsive nature permits adaptability addressing varying phases encountered fabrications likewise prevailing standards guiding developments Fatty-Alcohol possess greater electronegativities leading better affinities compared standard-fatty counterpart polymers extensively utilized transparency providing remarkable results facilitating dispersions other adjunctive elements Worth noting some polyols(e.g pentaerythritol)-derived esters augment densities ultimately elevating overall interactive intensities established surrounding matrices created ### Chapter Four : Trends Future Directions Concerning Plastics-Lubrics Current trajectories witness transitions evolving simplistic blends towards intricate design methodologies While mechanical mixtures traditionally favored simplicity potential antagonistic effects arising componential mismatches could detrimentally affect end-performances Modern synthesis techniques facilitate amalgamations embedding multiple functional units consolidated single-frameworks producing multifunctional species inclusive ester-amide-carboxyl combinations meeting growing environmental expectations necessitating alternatives devoid heavy-metals typical soaps Biobased substitutes sourced vegetable oils illustrate promising avenues adhering sustainability principles targeting specialized engineered-plastics/new-age composites becoming paramount focal points ahead