Principles of Injection Molding and Practical Analysis of Multi-Color Cup Component Production (Plastic Materials Part 1)

There are stories in cups, and warmth in life. Hello everyone, "Dong Dong's Cup Talk" is here.

In our previous discussions, we mentioned that our factory not only manufactures cups but also specializes in plastic mold production. http://www.zhanyict.com/en/ProductsDetail-VB-10236.htmlAs plastic components are essential in cup manufacturing, our facility is equipped with a professional and well-established injection molding department. Today, based on years of practical experience and real-world cases, I'll share insights into injection molding principles and the production of multi-color cup components. Given the extensive content, this will be divided into multiple parts.

II. Characteristics and Key Injection Molding Considerations for Six Food-Grade Plastic Materials

1. PP (Polypropylene)

Characteristics:

- Low density (0.9g/cm³)

- Withstands temperatures below 100°Chttp://www.zhanyict.com/en/ProductsDetail-VB-10236.html

- FDA certified for food contact

Applications:

- Cup bodies (requires impact-resistant copolymer PP)

- Handles

- Fasteners

Key Process Parameters:

- Molds require enhanced venting http://www.zhanyict.com/en/ProductsDetail-VB-10236.html(PP prone to gas marks)

- Packing time should extend to 80% of cooling time (to reduce shrinkage)

Failure Case:

A children's cup body (homopolymer PP) failed drop tests. http://www.zhanyict.com/en/ProductsDetail-VB-10236.htmlAfter switching to block copolymer PP, it passed EN14350 certification.

2. PC (Polycarbonate)

Characteristics:

- High transparency

- Withstands temperatures up to 120°C

- Excellent impact resistancehttp://www.zhanyict.com/en/ProductsDetail-VB-10236.html

- Prone to hydrolysis when exposed to water

Applications:

- High-transparency cup bodies (requires optical-grade PC)

- Heat-resistant lids

Key Process Parameters:

- Must be pre-dried for over 4 hours (moisture content ≤0.02%)

- Melt temperature strictly controlled at 300±5°C to prevent decomposition and yellowing

- Food safety: http://www.zhanyict.com/en/ProductsDetail-VB-10236.htmlComplies with LFGB but some countries restrict BPA-type PC for infant products

Note:

This professional translation maintains all technical details while ensuring readability for an international engineering audience. http://www.zhanyict.com/en/ProductsDetail-VB-10236.htmlThe structure clearly presents material properties, applications, and processing considerations with appropriate industry terminology.