I: Material overview
Plant staple fiber - bio-based composites is a new type of material emerging in recent years, the main raw materials taken from crop straw staple fiber, bamboo staple fiber, hemp staple fiber and so on.
By compounding with bio-based resins such as modified starch, soy protein glue, polylactic acid, etc., molding, injection molding, 3D printing can be made into disposable food and beverage containers and utensils, controllable degradation containers, handicrafts, daily necessities, construction panels, industrial packaging and other items.
Plant staple fiber - bio-based composite material products have high strength, natural surface texture, rustic, bright colors, novel texture and other characteristics, can replace some of the plastic, glass, ceramic, porcelain and other products, can be biodegradable after disposal, is a new type of environmentally friendly materials.
Plant staple fiber - bio-based composites (in terms of product composition) is the use of short hemp fiber, bamboo fiber or rice hulls, rice straw, straw, corn stalks, cotton stalks, bamboo shavings, and other crop stalks or stalks of other plants, crushed into 10 ~ 100 mesh of plant fibers or bundles of flakes, and then mixed with modified natural adhesive (matrix) to conform to the raw material, and then molded or injection molding;
The natural components of bio-based composites can reach 60%~90% or more; they can be made into disposable catering tableware, controllable degradable containers, handicrafts, daily necessities, construction plates, industrial packaging and other items.
Short Fibers - Bio-based composites can be classified by molding method, type of basic material, and type of plant short fiber.
As far as physical properties are concerned, plant staple fibers - bio-based composites have high strength, natural surface texture, rusticity, bright colors, novel texture, and are suitable for making many times and repeated use of items. After nearly a decade of research and development, the products made now can replace some of the plastics, glass, pottery, porcelain and other products.
Physical index of a certain product: density 1.1~1.4, static flexural strength -25Mpa, tensile strength -2MPa, modulus of elasticity 2700MPa.
Short fiber composites with plant short fibers as reinforcing materials, bio-based resin as the matrix material, two materials with different properties after the composite overall performance has been greatly improved. According to the different ways of composite can be divided into homogeneous composites and laminated composites.
Homogeneous composites
Reinforcing fiber: plant short fiber such as straw, reed, cotton stalks, production methods: mechanical crushing, blasting separation, soft wire
Base resins: starch-modified, bio-based polyurethane (microfoam), bio-based epoxy
Laminated composites
Reinforcing fibers: bio-based resin nonwoven fabrics, woven reed fabrics, waste chemical fiber fabrics
Matrix resin: starch-modified, bio-based polyurethane, bio-based epoxy
II: Development history and process introduction
1. Development history and downstream applications
Plant short fibers - bio-based composites began to mature from this century, downstream products were initially mainly disposable biodegradable tableware, with the development of technology, plant fibers and other materials for composite became mainstream. Products both in terms of appearance and quality than before have made great strides to improve.
Phase I:
Plant fiber biodegradable materials, disposable biodegradable tableware at the time of the main product (1995-2001)
Phase II:
Plant fiber environmentally friendly materials and series of products; the main products are disposable tableware, containers, handicrafts, daily necessities and product packaging. (2002-2005)
Phase III:
Starch-based (other polymers such as gelatin) natural fiber composites (straw fiber) 2005-2007
Phase IV:
Bio-based materials (2007-present - national standards development for bio-based materials)
2. Manufacturing process
Substrate material:
Modification of bio-based polymers, starch derivatives, or other natural polymers, and setting up of reaction plants in factories to produce body consultants and colloidal materials.
Material Mixing:
Setting up a mixing plant in the factory and mixing and cross-linking the materials with special mixing machines.
Molding:
Set up the main workshop in the factory, the equipment is a hot press, mixed raw materials added to different shapes of abrasives, high temperature and high pressure molding, each molding cycle of about 2 to 3 minutes
Injection molding:
Lassie test
Stereotypes:
Bio-based materials contain high moisture, in the molding process at the end of the extreme exclusion of part of the water, after the mold still has high moisture, optional natural drying requirements of the environment humidity is not greater than 60%, the product output is larger when the drying machine drying.
3. Relevant technologies
Mixing and reaction technology for the formulation of materials with a high content of natural ingredients
The proportion of natural plant fiber and natural polymer such as starch in the material is 60%~98%, and the remaining 2%~40% is natural polymer modifier, and the modifier selects environmentally friendly water-soluble synthetic polymer material, which is made into biobased material through mixing reaction.
Natural Fiber Production, Screening and Surface Treatment Technology
The main raw materials are all kinds of straw, which need to be crushed, separated, sorted and surface treated to improve strength, temperature resistance, waterproof and other properties.
High moisture content material crosslinking curing molding process control technology
Traditional polymer material molding requirements of the material moisture content of less than 1%, in order not to affect the material processing performance, our materials in the processing and molding process moisture content of 10% to 25%, its molding process is the key to the whole set of technology.
