Learn more about fiberglass

Learn more about fiberglass

Glass fiber is an inorganic non-metallic material with excellent properties. This material has very high insulation, heat resistance, corrosion resistance and mechanical strength. It is often used as reinforcement materials in composite materials, electrical insulation materials, thermal insulation materials, circuit substrates and other fields of the national economy. It is a national priority to encourage development. new materials industry. It is widely used in petroleum, chemical industry, construction, environmental protection, aviation, national defense and other fields.

The Ministry of Industry and Information Technology has issued the "Standardized Conditions for the Glass Fiber Industry". The "Standardized Conditions" cover construction layout, process technology and equipment, product quality and technological innovation, environmental protection, energy consumption, production safety, occupational health and social responsibility, supervision and management, etc. The fiberglass industry was regulated. In the next two years, a new round of stable growth window for glass fiber will begin to open.

Glass fiber production process flow chart

1. Raw material processing

The production of glass fiber is inseparable from the participation of non-metallic minerals. It mainly uses six kinds of ores as pyrophyllite, quartz sand, limestone, dolomite, boronite and boronite as raw materials. According to the national mineral resource reserve summary table (Ministry of Land and Resources, May 2016), as of the end of 2015, the identified resources of pyrophyllite ore nationwide were 99.9897 million tons, mainly distributed in Fujian, Zhejiang, and Jiangxi provinces. It is self-evident that quartz sand resources and production companies are in Qichun, Hubei, Donghai, Jiangsu, and Fengyang, Anhui, which are important places for quartz sand processing and application. It is rich in mineral resources such as limestone, dolomite, boronite and boronite.

What issues should we pay attention to when choosing raw materials?

1. Homogenization of raw material powder

The homogenization of powder can be carried out in various ways. There are three commonly used methods: ① mechanical homogenization ② gravity homogenization ③ pneumatic homogenization.

2. The raw material powder needs to control the following factors:

① Uniformity; ② Chemical composition; ③ Moisture content

2. Preparation of batch materials

1. Ingredients process

E glass powder is characterized by dry micro-powder with good fluidity. The preparation requires fully sealed operation to prevent dust from flying. Material transportation adopts pneumatic system; weighing adopts electronic scale; most mixing adopts pneumatic mixing and mixing conveying equipment. The conveying, weighing, mixing and sending of materials to the kiln head warehouse can be completed continuously and automatically. The ingredient production process mainly consists of three parts: feeding, weighing and mixing, and transportation.

2. Main ingredients and main equipment

① Pneumatic sending tank (single chamber pump); ② Screw feeder; ③ Pneumatic mixing tank; ④ Two-way distributor; ⑤ Electronic scale.

In addition, batch material preparation also involves quality testing (uniformity performance testing, COD value control), batch material control systems and other issues.

3. Melting of glass fiber

The melting process of glass fiber refers to the process in which the batch materials react with silicate at high temperature, melt and then transform into homogeneous glass liquid.

Melting refers to the process of solid phase melting after the batch reaction; clarification refers to the process of removing bubbles from the molten glass; and homogenization refers to the process of reducing defects such as lines, stripes, and nodules to an acceptable level. It is also The process of homogenizing the chemical composition of glass. These processes are carried out in stages.

4. Sizing agent for glass fiber

During the glass fiber drawing process, the surface of the glass fiber needs to be coated with a special surface treatment agent with a multi-phase structure based on organic emulsion or solution.

Function: Effectively lubricate the surface of glass fiber; integrate hundreds or even thousands of glass fiber monofilaments into a bundle; improve the surface condition of glass fiber; provide the characteristics required for further processing and application; make the glass fiber have good compatibility with the base material properties and interfacial chemical adsorption properties.

1. Classification of sizing agents

Enhanced sizing agent, textile sizing agent, enhanced textile sizing agent

2. Components of sizing agent

Wetting agent is a system composed of a variety of organic and inorganic substances. From the appearance, it can be deep liquid, emulsion, thixotropic colloid or paste. Because of its diverse functions and properties, its components are quite complex. Its formula contains the following main components and auxiliary components:

The main components are: ① coupling agent; ② film-forming agent; ③ lubricant; ④ antistatic agent

The auxiliary components are: ① wetting agent; ② pH adjuster; ③ plasticizer; ④ cross-linking agent; ⑤ preservative or bactericide; ⑥ defoaming agent; ⑦ pigment

5. Molding of glass fiber

After the high-temperature viscous glass liquid flows out from the leaking nozzle in drop form, it is drawn and solidified into continuous glass fibers of a certain diameter by the wire drawing machine below at a certain constant speed. At the lower part of the leak outlet, due to the balance of the surface tension and drafting force of the glass liquid, a crescent-shaped part with a gradually tapering diameter is formed, which is called the wire root. The distance from the leak outlet to the fiber with constant diameter is called the fiber forming line. The area containing this fiber forming line is called the fiber forming area. The distance from the leak outlet to the fiber winding point on the drawing machine is called the drawing line. This distance can be artificially longer or shorter depending on the process requirements.

6. Raw silk drying

In order to reduce the contact friction between the fiber and the bundler and cable organizer, protect the original shape of the fiber, and give the fiber some special properties, the outer surface of the fiber must be coated and wetted with an oiled roller or grooved wheel during the drawing and forming process. agent. This kind of sizing agent can be divided into two categories: starch type and reinforced type. The former is used for textile sand, and the latter is used for reinforced products. They are usually water emulsions. In addition to the main components such as lubrication and bonding, more than 80% of the liquid is water. Generally, the moisture contained in a raw silk cake is about 8% to 14% of its total weight. This moisture has adverse effects on subsequent processing steps and products, so it must be removed.

For non-reinforced ordinary glass fiber raw filaments, the moisture content of the raw filaments is allowed to be larger, and the raw filaments go through various processes such as drawing, unwinding, warping, and weaving for a long time, so only natural drying is sufficient. According to the production process and product requirements, the specific method is to hang the raw silk on a trolley and place it in a room at room temperature for 1 to 2 days to let it dry naturally. The raw yarn can also be dried with hot air (30~40℃) during unbundling.

The moisture content of reinforced glass fiber strands must be controlled within a certain range. Generally, the moisture content is around 0.1%, and some are as low as 0.07%. It is difficult to achieve the above requirements with natural drying, so special drying equipment must be used for artificial drying.

1. There are two main purposes for drying reinforced glass fiber strands:

① Remove the moisture in the raw silk cake to make the moisture content reach the specified index; ② After the binder in the sizing agent is heated and melted, it converts to polymerization, cross-linking, and film formation, so that the properties of the raw silk are improved.

2. Raw silk drying process

The drying process of glass fiber raw yarn in the drying oven can be roughly divided into two stages:

(1) Preheating: The preheating temperature is set to 105~120℃, and the preheating time is 1.5~3h.

(2) Drying: The drying temperature and time are determined by the requirements of various types of reinforced glass fiber strands and their corresponding sizing agents. The drying temperature is in the range of 120~135℃, and the drying time is in the range of 8~18h.

3. Factors affecting the drying of glass fiber strands include:

Temperature, air volume, relative humidity, thickness and arrangement of raw silk cakes, sizing agent, raw silk Tex, drying method

4. Types of drying ovens

(1) Batch furnace; (2) Steam tunnel furnace; (3) Microwave tunnel furnace

5. Composition of drying oven

(1) Heat source part; (2) Furnace structure; (3) Hot air circulation system; (4) Temperature control system; (5) Exhaust system; (6) Large tunnel drying furnace and transmission device