Question 2: filler introduction filler (English name filler) is also called filler, additive and filler (additive; Additives; Filler. A solid substance that can be added to a material to improve its performance, or to increase its capacity and weight and reduce its cost. Generally, organic, inorganic, metallic or nonmetallic powders which are neutral and have no adverse effect on the composition of materials can be used as fillers. Commonly used industrial fillers include kaolin, diatomite, talcum powder, graphite, carbon black, alumina powder, glass powder, asbestos powder, mica powder, quartz powder, carbon fiber, cork powder, emery and so on. Fillers are widely used in plastic processing, rubber processing, paper, coatings, pesticides, medicines and other products in chemical production, which not only improves the performance of these products, but also greatly reduces the production cost.
Question 3: What kind of filler calcium carbonate should be added to epoxy resin? If you want a better effect, you can use modified calcium carbonate, hydrophobic, or you can change it yourself. Aluminate is not very expensive to use.59980.999999989895
Question 4: Types of fillers What food additives can be divided into different types according to source classification, function classification and safety evaluation classification?
Internationally, food additives can be divided into three categories according to their sources: one is natural extract; Second, substances made by fermentation and other methods, such as citric acid, are chemically synthesized, but their structures are the same as natural compounds; The third is pure chemical compounds, such as sodium benzoate. At present, natural food additives are few in variety and high in price, and many low-priced synthetic food additives still occupy the mainstream of food additives application.
According to the function of food additives, food additives are divided into 20 categories, such as acidity regulator, anti-caking agent, defoamer and antioxidant, according to the Hygienic Standard for the Use of Food Additives GB2760- 1996. The application scope and uses of each food additive are described in detail. Because there are many kinds of spices, they are classified into another category separately.
According to the safety evaluation of food additives, CCFA divides them into three categories: A, B and C, and each category is divided into two categories, based on JECFA's discussion. The details are as follows:
Class A refers to people who have formulated ADI (Daily Allowable Intake) and provisional ADI by JECFA; Class A (1) refers to the person who thinks that the toxicological data is clear, the ADI value has been established or the toxicity is limited, and it is unnecessary to establish ADI; Class A (2) means that JECFA has tentatively set the ADI value, but the toxicological data is not perfect enough, so it is temporarily allowed to be used in food.
Class B means that JECFA has made safety evaluation, but has not established ADI value or made safety evaluation; Among them, Class B (1) refers to those whose safety evaluation has been made by JECFA, but ADI has not been established due to insufficient toxicological data; Category B(2) refers to those who have not been evaluated by JECFA.
Category C refers to those that JECFA considers unsafe for use in food or that should be strictly restricted for special use in certain foods: among them, Category C (1) refers to those that JECFA considers unsafe for use in food according to toxicological data; Class C (2) refers to substances that JECFA believes should be strictly restricted for special use in certain foods.
It should be noted that due to the continuous development of toxicology, analytical techniques and food safety evaluation, some foods considered safe by JECFA may change their safety evaluation results after re-evaluation.
The use of food additives shall meet the following requirements: (1) After food safety toxicology evaluation, it is proved that long-term use in * * * is safe and harmless to human body; (2) It does not affect the physical and chemical properties of food, and should not damage the nutritional components of food; (3) Food additives should have strict hygiene standards and quality standards, which were officially approved and published by People's Republic of China (PRC) and the Ministry of Health. (4) Food additives can be destroyed or allowed to have a small amount of residues after reaching a certain purpose and during processing, cooking or storage. (five) food additives shall not be used to cover up the defects of food or as a means of forgery; (6) Non-designated factories, unlicensed food additives and contaminated or deteriorated food additives shall not be used.
It is an indisputable fact that meat food additives can increase and maintain the original color, aroma and taste of meat products, which has been recognized and widely used by the food industry. Before an additive is put into use in national standards, it is necessary not only to analyze its composition and structure, but also to carry out a series of processes, such as hygiene investigation, toxicology test, determination of allowable daily intake (ADl), actual daily intake, and approval procedures for the production and use of new food additives. According to a series of use requirements of food additives, professional testing institutions have done a lot of tests, which prove that it is safe for human body in a certain range of use and under the conditions of * * * *. Some regular food production enterprises strictly implement the standards for adding food additives. The products they produce are inspected from the raw materials, and it is not allowed to use (or detect) the banned additives in the raw materials, so as to avoid the appearance of banned additives in the finished products. However, in the usual food supervision and spot checks, technical supervision departments often find that some additives allowed in some foods exceed the standard, and some even exceed the normal standard by several times or even dozens of times, and may also find that additives are not allowed. These are generally caused by informal manufacturers blindly pursuing benefits, not using raw and auxiliary materials according to regulations or using additives according to standards. In view of this phenomenon, we are strengthening national law enforcement ...
Question 5: What is white padding? It is a liquid to eliminate the white edge of tempered film. If you paint a little on the edge of the tempered film, it will penetrate into the white edge, and then the white edge will disappear. However, it has just come into the market. I wonder if this kind of thing will affect the screen of mobile phone. In addition, this kind of thing is more expensive now, and the film manufacturer will definitely give it away later.
Question 6: Classification and varieties of fillers There are many kinds and varieties of fillers, mainly the following: (1) Calcium carbonate: Calcium carbonate is the most common and cheapest filler, and calcium carbonate with different sources and properties is as follows: a common calcium carbonate (chalk): white crystal or powder, with a specific gravity of 2.70-2.95, soluble in acid but insoluble in water. Heated to 825℃ and decomposed into calcium oxide and carbon dioxide. Natural calcium carbonate minerals include limestone, calcite, lime and Datian stone. When they are ground into powder, they are called ordinary calcium carbonate. They are also different from dry grinding, and the particle size is between 1.5-44 microns. The particle size of dry grinding is more than 20 microns, and that of wet grinding is less than 20 microns. B precipitated calcium carbonate: powdered calcium carbonate generated by introducing carbon dioxide into limewater or precipitating sodium carbonate solution with limewater, generally divided into: light precipitated calcium carbonate; Heavy precipitated calcium carbonate with a specific gravity of 2.50-2.60; The specific gravity is 2.70-2.80; The particle size of precipitated calcium carbonate is 1.0- 16 micron, the specific surface area is 5-25 m/ g, and the refractive index is 65438. It is slightly hygroscopic. C active light calcium carbonate: this is a kind of light calcium carbonate with a layer of fatty acid soap adsorbed on the particle surface, tasteless and odorless white powder with a specific gravity of 1.99-2.438+0. The moisture content is less than 0.5%, the stearic acid content is 2-5%, the particle size is less than 0.65438 0 micron, the specific surface area is 25-28 m/g, and the refractive index is 65438 0.49. Insoluble in water and alcohol, it releases carbon dioxide when decomposed in acid, and it has no chemical change in air, only slightly hygroscopic. The activity is higher than that of ordinary calcium carbonate, and it has a slightly reinforcing effect. (2) Carbon black: This kind of filler includes all kinds of carbon black. Carbon black is the product of partial combustion or thermal decomposition of liquid or gaseous hydrocarbons in the absence of air. The elemental composition of carbon black is mainly carbon, containing only a small amount of hydrogen and oxygen. It is a black powdery substance with graphite-like crystal structure and colloidal particle size range. Due to different production processes, carbon black can be divided into many grades, but there are two commonly used in the plastic industry: a natural gas tank black: a black powdery substance with rough surface, which is easy to absorb moisture in the air. The average particle size is 23-30 nm, and the specific surface area is 130- 160m/ g. B mixed gas tank black: this is a kind of carbon black made by mixing anthracene oil and naphthalene in coal tar with natural gas after gasification. The so-called "structure" of carbon black refers to the tendency of carbon black to aggregate into strings, which plays an important role in the rheological properties of carbon black-polymer system. "High structure" carbon black promotes high viscosity, high elastic modulus, low flow rate and smooth and low swelling extrusion of polymers. Adding carbon black into polymer can not only protect photodegradation and thermal oxidation, but also improve the rigidity of plastic products. (3) Cellulose A shredded paper: kraft paper, white paper and colored paper can all be used as fillers. Generally, paper is soaked in resin, dried and sliced, and then pressed into plates. B wood flour: widely used in thermosetting resins, with high impact strength, low shrinkage, good electrical properties and low price. The particle size of wood flour should be uniform, and large particles such as sawdust and bark should be removed. C cotton scraps: cotton scraps are obtained by cutting or cleaning cotton. Plastic products filled with cotton scraps have improved impact resistance and large volume. D α- cellulose: α-cellulose is a colorless cellulose, which is the product of alkali treatment of wood pulp. Mainly used for light-colored urea-formaldehyde and melamine-formaldehyde resin formulations. The impact strength of products filled with α -cellulose is not as good as that filled with wood flour, and the hardness is high, which does not affect the specific gravity, while the molding shrinkage is low. E peanut shell: peanut shell is a cheap filler with high phenol content and rich sources. Peanut shell powder can improve the properties of HDPE, PS and PP and reduce the cost. The surface of peanut shell powder is generally nonpolar. Its water absorption is also smaller than that of wood flour. F Walnut shell: Walnut powder is the waste produced during walnut processing. Because it contains a lot of wood resin and keratin wax, it does not absorb water. G glass fiber; Mainly used for plastic reinforcement. (4) Silicate A asbestos: white to off-white fibrous substance. Stable chemical properties, strong alkali resistance, poor acid resistance, good electrical insulation and heat insulation. In the plastic industry, asbestos generally refers to chrysotile asbestos. The length of chrysotile fibers is different. The length of natural products is about 65438 0 inch, and the diameter is 0.025-0.035 micron, which needs to be shortened in industrial application. Fibers can be divided into fine fibers, soft fibers, silk fibers and coarse fibers. Rough fiber can't be bent, and it is easy to break when grinding; However, thin and soft filaments can be bent and not easily broken, but they have great strength and are widely used in plastic industry. & gt
Question 7: What is the purpose of using fillers in rubber compound? Using fillers in rubber compound can save a lot of raw rubber, thus reducing the cost of rubber. At the same time, the particle surface of general filler has certain chemical activity, which can reinforce the rubber compound and change the properties of vulcanized rubber in a large range. For example, in the rubber industry, carbon black is the second most important raw material, accounting for about 1/4- 1/3 of the tire weight. It can not only improve the strength of rubber products, but also improve the technological properties of rubber compounds, giving products various properties such as wear resistance, tear resistance, heat resistance, cold resistance and oil resistance, thus prolonging the service life of products. This filler is also called active filler or reinforcing agent. Another example is calcium carbonate, clay and so on. In some rubber compounds, the dosage is also large.
Question 8: What is the white filler? Very greasy. It is recommended to reattach the membrane nail. It is wrong to try.