1. What is phenolic resin?
Phenolic resin is also called bakelite powder.
Originally a colorless or yellowish-brown transparent substance, it is often sold in the market in colors such as red, yellow, black, green, brown, blue, etc., with colorants added, and in the form of granules and powder. Resistant to weak acids and weak alkali, will decompose when exposed to strong acid and corrode when exposed to strong alkali.
Insoluble in water, soluble in acetone, alcohol and other organic solvents. Phenolic resin is a general term for resinous substances obtained by the condensation polymerization of phenol and its homologues or substituted phenols and aldehydes.
Among them, phenolic resin obtained by the condensation polymerization of phenol and formaldehyde is the most important. It includes: novolac resin, thermosetting phenolic resin and oil-soluble phenolic resin.
Mainly used to produce compression molding powder and laminated plastics; manufacture varnish or insulation and corrosion-resistant coatings; manufacture daily necessities and decorations; manufacture sound insulation and heat insulation materials, etc.
2. The historical development of synthetic resin
The secretions of some trees often form resin, but amber is the fossil of resin. Although shellac is also regarded as resin, it is Sediments secreted by lac bugs on trees.
Shellac paint, made from shellac, was originally only used as a wood preservative, but with the invention of the motor it became the earliest insulating paint used. However, after entering the 20th century, natural products can no longer meet the needs of electrification, prompting people to find new cheap substitutes.
As early as 1872, German chemist A. Bayer first discovered that phenol and formaldehyde could quickly form reddish-brown hard lumps or viscous substances when heated under acidic conditions. However, they could not be dissolved by classic methods. The experiment was stopped for purification. After the 20th century, phenol can be obtained in large quantities from coal tar, and formaldehyde is also produced in large quantities as a preservative. Therefore, the reaction products of the two have attracted more attention, and it is hoped to develop useful products, although many people have spent a lot of labor on it. , but none of them achieved the expected results.
In 1904, Baekeland and his assistants also carried out this research. The original purpose was just to make an insulating paint that could replace natural resin. After three years of hard work, finally in the summer of 1907, Not only insulating paint was produced, but also a truly synthetic plastic material - Bakelite, which is known as "Bakelite", "Bakelite" or phenolic resin. Once Bakelite came out, manufacturers soon discovered that it could not only make a variety of electrical insulation products, but also daily necessities. T. Edison used it to make records, and soon announced in an advertisement that thousands of products had been made with Bakelite. product, Baekeland's invention was immediately hailed as the "alchemy" of the 20th century.
Before 1940, phenolic resins based on coal tar as raw particles had always ranked first in the output of various synthetic resins, reaching more than 200,000 tons per year. However, with the development of petrochemical industry since then, polymeric resins have The output of synthetic resins such as polyethylene, polypropylene, polyvinyl chloride and polystyrene has also continued to expand. With the establishment of many large-scale factories with an annual output of more than 100,000 tons of such products, they have become the four categories with the largest output today. Synthetic resin. Today, synthetic resins are added with additives, and plastic products are obtained through various molding methods. There are dozens of varieties of plastics. The world's annual output is about 120 million tons, and our country's is also more than 5 million tons. They have become a production, Basic materials for daily life and national defense construction.
. 3. What is the history of the discovery of vanadium?
Vanadium was discovered twice.
It was first discovered in 1801 by the mineralogy professor Jie Leriva in Mexico City. He found it in the vanadate sample. The vanadium ore sample was Pb5(VO4)3Cl. Because the salt solution of this new element showed a bright red color when heated, it was named "Elitrone". That means "red" and sent him to Paris.
However, French chemists concluded that it was a contaminated chromium ore, so it was not recognized.
The second discovery was made in 1830 by Swedish chemist Sefstrom NG (1787-1845.)
While studying the iron ore in the Smaland mining area, he used acid to dissolve iron and found it in the residue. Vanadium was discovered. Because the colors of vanadium compounds are colorful and very beautiful, this new element was named "Vanadium" after a beautiful goddess named Vanadis in ancient Greek mythology.
The Chinese name is vanadium according to its transliteration. Sefstrom, Weller, Berzelius and others have all studied vanadium and confirmed its existence, but they have never isolated elemental vanadium.
Later in 1830, the Buddhist monk Thelemu discovered it in iron extracted from Swedish iron ore and determined that it was a new element called vanadium. He was able to prove that it was a He discovered a new element and thus defeated a competing chemist, Friedrich W?hler from Cimapán (Mexico), who was also working on another vanadium ore. More than thirty years after Sefstr?m discovered vanadium, in 1869 the British chemist Roscoe HE (1833-1915) reduced vanadium dioxide with hydrogen and produced pure metallic vanadium for the first time, and he proved The previous metal sample was actually vanadium nitride (VN).
. 4. Is the first artificial polymer in human history a phenolic resin?
It seems not.
In April 1997, Frank Baker, an emergency medicine expert from the Chicago area Baker, is participating in a clinical trial testing the form of artificial skin suitable for people with insulin-dependent diabetes who are being treated for tissue degeneration due to the side effects of chronic high blood sugar. Baker himself has been diabetic for 40 years and is in danger of losing a foot due to incurable skin ulcers. For him, the results of the experiment were nothing short of miraculous: The skin grown in the lab not only covered and protected his wounds, it also released a chemical that caused his own tissue to heal much faster. The speed begins to recover. In Dr. Baker's own words: Artificial skin saved my feet.
The substance that makes this medical miracle work is synthesized from polymers, which are actually long molecular chains of many different small molecules chemically combined together.
The first synthetic skin was invented by Baker, head of the trauma department at Massachusetts General Hospital, and Janos, a professor of chemistry at MIT. 5. What are the types of phenolic resin?
A type of paint made with phenolic resin or modified phenolic resin as the main film-forming substance is called phenolic paint.
Phenolic resin is one of the earliest synthetic resins developed and has been used in the manufacture of coatings for nearly 70 years. Although synthetic resin is currently quite developed, it still occupies a large proportion in the coating industry and is widely used due to its low cost and the ability to impart certain hardness, gloss, quickness, water resistance, acid and alkali resistance, and insulation properties to the coating. In wood, construction, shipbuilding, machinery, electrical and anti-chemical corrosion coatings, etc.
Phenolic resin is a resin produced by the polycondensation reaction of phenol and aldehyde. The main raw materials are phenol and formaldehyde. In addition, other phenols can also be used, such as cresol, xylenol, benzene and other aldehydes such as furfural. Sometimes the condensation polymerization of aniline, phenol and formaldehyde is also used. A common reaction to generate phenolic condensates is formaldehyde and phenol to generate hydroxymethyl phenol, which is then further condensed to remove water and produce a condensate to form a methylene bridge. The reaction formula is as follows:
According to the raw materials used Depending on the chemical structure, the molar ratio of phenol to aldehyde, and the properties of the catalyst, the phenolic resins produced have different properties. Types of phenolic resins used in coatings, phenolic resin coatings and their applications are discussed below.
1. Types of phenolic resins for coatings
There are three types of phenolic resins for coatings: alcohol-soluble phenolic resins, modified phenolic resins and oil-soluble phenolic resins.
Among these three resins, the paint made from 100 oil-soluble pure phenolic resin and tung oil has the best performance, but the source of the resin is scarce and the cost is high, so it is not used in large quantities; rosin-modified phenolic resin has a wide range of sources , low cost, easy to operate during refining, and the paint refined with tung oil still partially retains the chemical resistance, weather resistance, water resistance, and insulation properties of the phenolic resin. The paint film is bright and hard, and can be dried or dried in the phenolic resin. Resin paints account for a large proportion; alcohol-soluble phenolics are not widely used.
2. Uses of phenolic resin paint
1) Alcohol-soluble phenolic resin paint
This type of paint is made from alcohol-soluble phenolic resin dissolved in alcohol solvents Generally, they are thermosetting phenolic varnishes. They are a type of paint that does not require grease. After baking and drying, the paint film is tough and has good adhesion. It has good oil resistance, water resistance, heat resistance, acid and alkali resistance and solvent resistance. It also has good insulation and a certain bonding strength, and is mostly used for bonding laminates, surface treatment of electrical insulation parts, and coating of the interior of cans and bottom lids. For example, F01 6 phenolic fermentation varnish has good moisture resistance and insulation properties and is used for adhesive layer products and insulating parts.
2) Modified phenolic resin
Unmodified phenolic resin is immiscible with oils and other resins. If the paint is made separately, the paint film will be brittle, so Fewer applications. In phenolic paints, most of the phenolic resins used are modified phenolic resins. After modification, the phenolic resins improve the oil solubility and miscibility of some other resins. They are widely used in phenolic paints and other paints. application. There are generally two methods for modifying phenolic resin: rosin modification and butanol modification.
① Rosin-modified phenolic resin paint: This type of paint is a paint of various oiliness made by refining rosin-modified phenolic resin and drying oil, and then adding driers, solvents, Pigments are prepared by grinding and grinding. The products include various varnishes, enamels, primers and putties.
The paint film of rosin-modified phenolic resin paint is hard and durable, has good drying properties, has certain water resistance, acid and alkali resistance, and insulation properties. It is also cheap and has many varieties. It plays an important role in phenolic paints. The disadvantage is that the paint film is prone to yellowing. This type of paint is widely used in wood furniture, construction, general machinery products, ships, insulating paint, etc.
②Butanol-modified phenolic resin paint: This type of paint is made of butanol-modified phenolic resin dissolved in benzene solvent as the main film-forming substance. The paint film has good water resistance and acid resistance. , but it is brittle and needs to be baked and dried at high temperature. Therefore, it is generally used in combination with oil or other resins. The paint film produced has good corrosion resistance and flexibility, such as F23-2 phenolic can paint, F52 1 phenolic anti-corrosion baking paint, etc., all belong to this type of paint.
3) Oil-soluble pure phenolic resin paint
This type of paint is made of oil-soluble phenolic resin and dry oil thermal refining products.
According to the different proportions of pure phenolic resin and oil, paint can also be divided into three types: short, medium and long oil, and can be made into primers, enamels and varnishes.
Pure phenolic resin has good water resistance, acid resistance, solvent resistance and electrical insulation properties. The paint film produced after being heated with dry oil, especially with tung oil, is hard. It has toughness, fast drying, good adhesion, and weather resistance slightly inferior to alkyd resin paint, but its water resistance and chemical corrosion resistance are better than alkyd paint. Therefore, pure phenolic resin paint is suitable for underwater and outdoor anti-corrosion coatings. , it has a relatively prominent position in coatings used in ships, chemical equipment, and electrical insulation, and can be matched with various topcoats. Like epoxy primer, it is an important type of metal primer and has been widely used.
However, all types of phenolic paints have varying degrees of yellowing, so there is generally no white enamel paint variety among the phenolic paints.
3. Key points for phenolic resin paint construction
Pay attention to the following points when constructing phenolic resin paint:
① Alcohol-soluble phenolic resin paint uses ethanol as a diluent.
The modified phenolic resin paint uses No. 200 solvent gasoline or turpentine as the diluent, the oil-soluble pure phenolic short oil paint uses xylene as the diluent, and the medium oil paint uses xylene and No. 2∞ solvent gasoline
A mixture of 50% each is used as a thinner. The thinner for long oil paint is No. 200 solvent gasoline or turpentine.
②This type of paint can be applied by brushing or spraying. Working viscosity: 20s~30s for spraying and 70s~110s for brushing.
③Drying conditions: It takes 18h to dry at room temperature F.
④Drying paint must be baked according to technical requirements. 6. Who can talk about the history of plastics
1. The development history of plastics
The use of natural resin can be traced back to ancient times, but the modern plastics industry was formed in 1930. In the past 40 years, Has achieved rapid development.
The name resin comes from the lipids secreted by trees. The earliest natural resins used by humans were rosin, shellac, etc. The production of natural resin is limited by the region, so the output is not large, the quality is not high, and the use is restricted. In order to seek a substitute for natural resin, people used cellulose (cotton) and nitric acid to prepare nitrocellulose in 1846. They mixed moist nitrocellulose and camphor to make a substitute for shellac, and a factory was built in 1872 for production. Although it has been more than a hundred years since its discovery, it is still widely used. The common name is celluloid, such as table tennis balls, toys, combs, buttons, etc. With the growth of human demand for plastic materials and the improvement of science and technology, people have developed synthetic resins that are much more versatile than natural resins. Synthetic resin is a high-molecular-weight resinous substance produced by chemical reactions of low-molecular-weight compounds. It is generally solid at normal temperatures and pressures, and may also be a viscous liquid. The first synthetic resin variety was thermosetting phenolic resin (commonly known as Bakelite), which was produced from phenol and formaldehyde under the action of a catalyst. Starting from the establishment of the first phenolic resin factory in 1907, the period of synthetic polymers began. In 1931, the industrial production of the first thermoplastic resin polyvinyl chloride resin began. Since then, the synthetic polymer industry has developed rapidly, and polystyrene Ethylene, polyvinyl acetate, polymethylmethacrylate, etc. are gradually produced industrially. There are currently about 30 major categories of resins produced industrially. Among the three major synthetic materials (synthetic resins and plastics, synthetic rubber, and synthetic fibers), synthetic resin is the earliest produced, has the largest output, and is the most widely used. According to statistics, the world's synthetic resin output in 1995 was about 120 million tons, and the synthetic resin output in mainland my country was about 4.4 million tons. 7. History of the discovery of molecules
History of plastics industry (Volume title: Chemical Industry) History of plastics industry Since the birth of the first plastic product, celluloid, the plastics industry has a history of 120 years.
Its development history can be divided into three stages. Natural polymer processing stage This stage is characterized by the modification and processing of natural polymers, mainly cellulose.
In 1869, American J. W.
Hyatt discovered that adding camphor and a small amount of alcohol to nitrocellulose can produce a plastic substance that can be shaped into plastic products under hot pressure, named celluloid. A factory was built in Newark, USA in 1872.
In addition to being used as ivory substitutes, it was also processed into windshields for carriages and cars, and film films. Since then, the plastics industry has been created, and molding technology has been developed accordingly. In 1903 German A.
Eichengreen invented non-flammable cellulose acetate and the injection molding method. In 1905, the German Bayer AG started industrial production.
During this period, some chemists synthesized a variety of polymers in the laboratory, such as novolac resin, polymethyl methacrylate, polyvinyl chloride, etc., laying the foundation for the subsequent development of the plastics industry. foundation. In 1904, the world's plastic production was only 10kt, and an independent industrial sector had not yet formed.
Synthetic resin stage This period is characterized by the production of plastics using synthetic resin as the basic raw material. In 1909 American L.
H. Baekeland made breakthrough progress in using phenol and formaldehyde to synthesize resin, and obtained the patent for the first thermosetting resin, phenolic resin.
After adding fillers to phenolic resin, it is hot-pressed to make molded products, laminates, coatings, adhesives, etc. This is the first completely synthetic plastic.
In 1910, the General Phenolic Resin Company was established in the Rügers factory in Berlin for production. Before the 1940s, phenolic plastics were the most important type of plastic, accounting for about 2/3 of plastic production.
Mainly used in electrical appliances, instruments, machinery and automobile industries. After 1920, the plastics industry developed rapidly.
The main reason is first of all the German chemist Н. Staudinger proposed the theory that polymer chains are composed of repeating units with the same structure connected by ***valent bonds and the theory of cross-linked network structure of infusible and insoluble thermosetting resins. In 1929, American chemist W.
H. Carothers proposed the theory of condensation polymerization, which laid the foundation for the development of polymer chemistry and plastics industry.
At the same time, due to the rapid development of the general chemical industry at that time, a variety of polymer monomers and other raw materials were provided for the plastics industry. Germany, which had the most developed chemical industry at that time, was eager to get rid of its heavy reliance on natural products to meet its various needs.
These factors have strongly promoted the development of synthetic resin preparation technology and processing industry. The first colorless resin was urea-formaldehyde resin.
In 1928, it was put into industrial production by the British Cyanamid Company. In 1911, British F.
E. Matthews made polystyrene, but there were problems such as complex processes and aging of the resin.
In 1930, the German Farben Company solved the above problems and carried out industrial production using bulk polymerization in Ludwigshafen. In the research and production process of polystyrene modification, styrenic resins based on styrene and polymerized with other monomers have gradually been formed, expanding its application scope.
In 1931, the American Rohm-Haas Company produced polymethylmethacrylate using the bulk method to create organic glass. In 1926, the United States W.
L. Simon dissolved polyvinyl chloride powder that had not yet found a use in a high-boiling solvent under heating. After cooling, he unexpectedly obtained plasticized polyvinyl chloride that was soft, easy to process, and elastic.
This accidental discovery opened the door to the industrial production of polyvinyl chloride. In 1931, the German company Farben used the emulsion method to produce polyvinyl chloride in Bitterfeld.
In 1941, the United States developed the technology of suspension production of polyvinyl chloride. Since then, polyvinyl chloride has been an important plastic variety, and it is also one of the main chlorine-consuming products, affecting the production of the chlor-alkali industry to a certain extent.
In 1939, the American Cyanamid Company began producing melamine-formaldehyde resin molding powders, laminates and coatings. In 1933, while conducting experiments on the high-pressure reaction of ethylene and benzaldehyde by the British Burnemann Chemical Industry Company, they discovered the presence of waxy solids on the walls of the polymerization kettle, thus inventing polyethylene.
In 1939, the company used the high-pressure gas phase bulk method to produce low-density polyethylene. In 1953 the Federal Republic of Germany K.
Ziegler used alkyl aluminum and titanium tetrachloride as catalysts to make ethylene into high-density polyethylene under low pressure. In 1955, the Hoechst Company of the Federal Republic of Germany first industrialized it. Soon, the Italian G.
Natta invented polypropylene, which was first industrially produced by the Italian Montecatini Company in 1957. Since the mid-1940s, polyester, silicone resin, fluororesin, epoxy resin, polyurethane, etc. have been put into industrial production.
The total world output of plastics surged from 10kt in 1904 to 600kt in 1944, and reached 3 in 1956. 4Mt.
With the development of general-purpose plastics such as polyethylene, polyvinyl chloride and polystyrene, the raw materials have also shifted from coal to petroleum. This not only ensures an adequate supply of polymer chemical raw materials, but also promotes It has promoted the development of petrochemical industry, enabled the multi-level utilization of raw materials, and created higher economic value. Great Development Stage During this period, the output of general plastics increased rapidly. In the 1970s, polyolefin plastics such as poly-1-butene and poly-4-methyl-1-pentene were put into production.
Forming the world's largest polyolefin plastic series. At the same time, many varieties of high-performance engineering plastics have emerged.
In the 16 years from 1958 to 1973, the plastics industry was in a period of rapid development. In 1970, the output was 30Mt. In addition to the rapid increase in output, its characteristics are: ① From a single large variety to a series of varieties through polymerization or polymerization modification.
For example, in addition to producing various brands of polyvinyl chloride, we have also developed chlorinated polyvinyl chloride, vinyl chloride-vinyl acetate polymer, and vinyl chloride-vinylidene chloride polymer. , mixed or grafted polymer-modified impact-resistant polyvinyl chloride, etc. ② Developed a series of new varieties of high-performance engineering plastics.
Such as polyformaldehyde, polycarbonate, ABS resin, polyphenylene ether, polyimide, etc. ③ New technologies such as reinforcement, compounding and hybrid mixing are widely used to give plastics better comprehensive properties and expand their application scope.
In the 10 years after 1973, the energy crisis affected the development speed of the plastics industry. In the late 1970s, the world's annual total production of major plastic varieties was: polyolefin 19Mt, polyvinyl chloride more than 100kt, polystyrene close to 80kt, and the total plastic production was 63.
6Mt. 8. The development history of the plastics industry
Counting from the birth of the first plastic product, celluloid, the plastics industry has a history of 120 years. Its development history can be divided into three stages.
Natural polymer processing stage This period is characterized by the modification and processing of natural polymers, mainly cellulose. In 1869, American J.W. Hyatt discovered that adding camphor and a small amount of alcohol to nitrocellulose can produce a plastic substance that can be shaped into plastic products under hot pressure, named celluloid. In 1872, a factory was built in Newark, USA. At that time, in addition to being used as ivory substitutes, it was also processed into windshields for carriages and cars, and film films. Since then, the plastics industry has been created, and molding technology has been developed accordingly.
In 1903, German A. Eichengreen invented non-combustible cellulose acetate and the injection molding method. In 1905, the German Bayer AG started industrial production. During this period, some chemists synthesized a variety of polymers in the laboratory, such as novolac resin, polymethyl methacrylate, polyvinyl chloride, etc., which laid the foundation for the subsequent development of the plastics industry. In 1904, the world's plastic output was only 10kt, and an independent industrial sector had not yet formed.
Synthetic resin stage This period is characterized by the production of plastics using synthetic resin as the basic raw material. In 1909, American L.H. Baekeland made a breakthrough in using phenol and formaldehyde to synthesize resin, and obtained the patent for the first thermosetting resin, phenolic resin. After adding fillers to phenolic resin, it is hot-pressed to make molded products. 9. Brief history of PVC resin
PVC resin is a polar amorphous polymer with strong interaction between molecules. It is a hard and brittle material; its impact strength is low.
After adding impact modifier, the elastomer particles of the impact modifier can reduce the total craze-induced stress, and use the deformation and shear band of the particles themselves to prevent the expansion and growth of craze. Absorb the impact energy passed into the body of the material to achieve the purpose of impact resistance. The particles of the modifier are very small, which facilitates increasing the amount of the modifier per unit weight or unit volume, increasing its effective volume fraction, thereby enhancing the ability to disperse stress.
Currently, organic impact modifiers are widely used.
I suggest you go to DaChem.com to look for articles about PVC resin, which will be helpful to you. 1. The development history of vinyl ester resin
Vinyl ester resin is produced by the chemical reaction of epoxy resin and methacrylic acid through ring-opening addition. It retains the basic chain segments of epoxy resin and has the good process properties of unsaturated polyester resin. After curing under appropriate conditions, it shows some special excellent properties. Therefore, it has developed rapidly since the 1960s. First, the Epocrgl brand was launched by Shell Chemical of the United States, and then the Derakane brand was launched by Dow Chemical of the United States in 1966, followed closely by the Hetron brand of Ashland Chemical. , as well as the Ripoxy brand of Japan's Showa Polymer Co., Ltd., other foreign brands or manufacturers include AOC, Interplastics, etc., and China has also developed its own vinyl ester resin, such as Shanghai Fuchen FUCHEM, Huachang MFE, Shanwei SWANCOR et al. With the development of vinyl resin, more and more companies are producing vinyl ester resin, so there are currently many brands and varieties on the domestic and foreign markets. The main manufacturers and brands are as follows:
Table 2.1 List of domestic and foreign vinyl ester resin brands Company Dow Chemical Ashland Chemical Showa Polymers DSM Company Shanwei Enterprise Shanghai Fuchen Reichhold Country United States United States Japan Netherlands Taiwan China Shanghai Norwegian brand Derakane Hetron Ripoxy Atlac Swancor Fuchem Norpol Dion Standard bisphenol A epoxy vinyl ester 411 922 806 430 901 854 9100 Flame retardant epoxy vinyl ester 510 992 550 750 905 892 9300 Novolac epoxy vinyl ester 470 980 630 590 907 890 9400 High cross-linking density epoxy vinyl ester — 970 600 — 977 898 9700 Flexible epoxy vinyl ester 8084 — — — 980 810 — PU modified epoxy vinyl ester — — — 580 — 820 9800