{"id":16473,"date":"2026-08-28T11:00:05","date_gmt":"2026-08-28T11:00:05","guid":{"rendered":"https:\/\/www.ruydelacerda.pt\/?p=16473"},"modified":"2026-08-28T09:23:53","modified_gmt":"2026-08-28T09:23:53","slug":"black-specks-in-recycled-plastic-pellets-what-causes-them","status":"publish","type":"post","link":"https:\/\/www.ruydelacerda.pt\/en\/black-specks-in-recycled-plastic-pellets-what-causes-them\/","title":{"rendered":"Black specks in recycled plastic pellets: what causes them?"},"content":{"rendered":"\t\t
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(English Below) \ud83c\uddf5\ud83c\uddf9<\/p>\n

Os pontos negros, as bolhas, os odores e as altera\u00e7\u00f5es de cor s\u00e3o problemas frequentes na produ\u00e7\u00e3o de granulado reciclado. Al\u00e9m de prejudicarem o aspeto, podem afetar o desempenho do material e limitar a sua utiliza\u00e7\u00e3o em produtos mais exigentes.<\/p>\n

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\ud83d\udca7 Lavagem insuficiente<\/strong>
Restos de gorduras, colas, etiquetas, papel e outras impurezas podem permanecer no pl\u00e1stico. Ao entrarem na extrusora, estes contaminantes degradam-se com o calor e transformam-se em part\u00edculas escuras.<\/p>\n

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\ud83c\udf2c\ufe0f Humidade no material<\/strong>
Quando o pl\u00e1stico n\u00e3o \u00e9 corretamente seco, a humidade pode provocar bolhas, poros e irregularidades. Em alguns pol\u00edmeros, tamb\u00e9m acelera a degrada\u00e7\u00e3o e reduz as propriedades do granulado.<\/p>\n

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\u2699\ufe0f Extrus\u00e3o desregulada<\/strong>
Temperaturas demasiado elevadas, varia\u00e7\u00f5es de press\u00e3o ou um tempo de perman\u00eancia excessivo podem queimar o pl\u00e1stico. O material retido em determinadas zonas da extrusora tamb\u00e9m pode carbonizar e contaminar os lotes seguintes.<\/p>\n

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\ud83d\udd0d Filtragem inadequada<\/strong>
Filtros saturados, danificados ou com uma malha pouco adequada deixam passar part\u00edculas e outras impurezas. A filtragem deve ser ajustada ao n\u00edvel de contamina\u00e7\u00e3o da mat\u00e9ria-prima.<\/p>\n

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\ud83e\uddf9 Falta de limpeza dos equipamentos<\/strong>
Res\u00edduos acumulados no fuso, cilindro, cabe\u00e7a ou fieira degradam-se e podem desprender-se durante a produ\u00e7\u00e3o. A limpeza e a manuten\u00e7\u00e3o preventiva s\u00e3o fundamentais, sobretudo nas mudan\u00e7as de material ou de cor.<\/p>\n

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Na Ruy de Lacerda<\/strong>, conhecemos os desafios associados ao processamento de pl\u00e1stico reciclado. Controlar a lavagem, a secagem, a extrus\u00e3o, a filtragem e a limpeza ajuda a reduzir imperfei\u00e7\u00f5es e a obter um granulado mais uniforme e consistente. \u267b\ufe0f<\/p>\n

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E na sua ind\u00fastria? Que medidas utiliza para garantir a qualidade do seu granulado reciclado?<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t

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\ud83c\uddec\ud83c\udde7<\/p>\n

\u267b\ufe0f Black specks in recycled plastic pellets: what causes them?<\/strong><\/h5>\n

Black specks, bubbles, odours and colour variations are common problems in the production of recycled plastic pellets. Besides affecting their appearance, these defects can compromise the material\u2019s performance and limit its use in more demanding applications.<\/p>\n

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\ud83d\udca7<\/strong> Insufficient washing<\/strong><\/p>\n

Traces of grease, adhesives, labels, paper and other impurities may remain on the plastic. When they enter the extruder, these contaminants degrade under heat and turn into dark particles.<\/p>\n

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\ud83c\udf2c\ufe0f<\/strong> Moisture in the material<\/strong><\/p>\n

When the plastic is not properly dried, moisture can cause bubbles, pores and irregularities. In some polymers, it can also accelerate degradation and reduce the pellet\u2019s properties.<\/p>\n

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\u2699<\/strong>\ufe0f<\/strong> Incorrect extrusion settings<\/strong><\/p>\n

Excessively high temperatures, pressure variations or prolonged residence times can burn the plastic. Material trapped in certain areas of the extruder may also carbonise and contaminate subsequent batches.<\/p>\n

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\ud83d\udd0d<\/strong> Inadequate filtration<\/strong><\/p>\n

Saturated or damaged filters, or filters with an unsuitable mesh size, allow particles and other impurities to pass through. Filtration must be adjusted according to the contamination level of the raw material.<\/p>\n

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\ud83e\uddf9<\/strong> Insufficient equipment cleaning<\/strong><\/p>\n

Residues accumulated on the screw, barrel, die head or die can degrade and break loose during production. Cleaning and preventive maintenance are essential, particularly when changing materials or colours.<\/p>\n

At Ruy de Lacerda, we understand the challenges associated with processing recycled plastics. Controlling washing, drying, extrusion, filtration and cleaning helps reduce imperfections and produce more uniform and consistent pellets. \u267b\ufe0f<\/p>\n

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And in your industry? What measures do you use to ensure the quality of your recycled plastic pellets?<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"

Black specks, bubbles, odours and colour variations are common problems in the production of recycled plastic pellets. Besides affecting their appearance, they can also compromise the material\u2019s performance…<\/p>\n","protected":false},"author":2,"featured_media":16468,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_joinchat":[],"footnotes":""},"categories":[183],"tags":[],"class_list":["post-16473","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-circular-economy"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.ruydelacerda.pt\/en\/wp-json\/wp\/v2\/posts\/16473","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ruydelacerda.pt\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ruydelacerda.pt\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ruydelacerda.pt\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ruydelacerda.pt\/en\/wp-json\/wp\/v2\/comments?post=16473"}],"version-history":[{"count":1,"href":"https:\/\/www.ruydelacerda.pt\/en\/wp-json\/wp\/v2\/posts\/16473\/revisions"}],"predecessor-version":[{"id":16474,"href":"https:\/\/www.ruydelacerda.pt\/en\/wp-json\/wp\/v2\/posts\/16473\/revisions\/16474"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ruydelacerda.pt\/en\/wp-json\/wp\/v2\/media\/16468"}],"wp:attachment":[{"href":"https:\/\/www.ruydelacerda.pt\/en\/wp-json\/wp\/v2\/media?parent=16473"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ruydelacerda.pt\/en\/wp-json\/wp\/v2\/categories?post=16473"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ruydelacerda.pt\/en\/wp-json\/wp\/v2\/tags?post=16473"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}