PVC stabilizers detection

1 hydrotalcite, organic auxiliary classes of organic compounds such as single-use type, the thermal stability is not good, often with a metal-containing heat stabilizer compound used. Currently used thermal stabilizers are organic polyols, phosphite, epoxidized soybean oil, 1,3 - dione. Polyhydric alcohol is the mechanism: generating a complex catalytic effect of chloride, thereby enhancing the effect of the thermal stability of metal. The most commonly used polyols are pentaerythritol, dipentaerythritol sorbic alcohol. WangMing other studies of pentaerythritol heat stabilizer for calcium zinc thermal stabilization, S.van E.Daan polyols and other studies on PVC processing performance. Organic phosphite heat stabilizer is the most important and the calcium stearate largest use one, when compounded with the metal soap is used, the effect is obvious. Commonly used are alkyl and aryl phosphites. Epoxy oils has attracted more and more people's attention, such compounds are characterized by a molecule containing one or more epoxy groups, PVC heat generated when hydrogen chloride, an epoxy group to quickly react with , blocking the hydrogen chloride from the catalyst for PVC, thereby improving the thermal stability of PVC. As the epoxy oils of PVC has a strong plasticizing action and non-toxic, in recent years, many such as food packaging for soft cork bottle plasticizers and heat stabilizers. Wu Maoying other studies β-diketone compound and zinc heat stabilizing effect, that the β-diketone complexes of zinc with excellent thermal stability performance. PVC heat stabilizers organic research is entering the 21st century one of the hotspots. As the representative of Egypt Sabaa researchers studied a variety of organic compounds and their derivatives stabilizing effect on PVC, typical substances vanillin - Schiff base, barbituric acid, etc. These organic compounds have excellent thermal stability. In addition to the calcium zinc stabilizer organic auxiliary heat stabilizers, thermal stability of the PVC industry, hydrotalcite, synthetic zeolites, and other inorganic perchlorate also used in supplemental heat stabilizers. Hydrotalcite layered inorganic metal material, its molecular formula is: Mg6Al2 (OH) 16CO3, while water of crystallization with a conventional synthesized by coprecipitation method. When a hydrotalcite is used as heat stabilizers for PVC, and PVC processing can be released during the degradation reaction of hydrogen chloride, when the hydrotalcite is used alone as heat stabilizers for PVC, the effect is not ideal, and a metal soap compound generally used. Hydrotalcite obvious disadvantage is poor compatibility with PVC, in recent years, different researchers by reducing the size of the hydrotalcite to improve their dispersion in PVC or molecular modification hydrotalcite enhance compatibility. Synthetic zeolite molecular sieves or more types of structure of the compound, usually containing oxides of silicon and aluminum composite, also contain water of crystallization, the molecule containing regular pore structure. In recent years, zeolite PVC industry as a heat stabilizer also been studied and used. Using an oil bath pot, built glycerin, will be tested PVC heat stabilizers mixed with the material after being loaded into a small test tube, so that the material becomes a slight concussion and firm, and then placed in an oil bath pot among glycerol oil bath pot set in advance a temperature of approximately 170 ℃, PVC material within the small tube and the upper surface of the upper surface level of glycerin, small tube top, with a thin tube inserted into the plug, the upper and lower transparent glass, the glass tube Congo red paper hit the bottom of the roll inserted so Congo red paper with the lower edge of the upper edge of the PVC material is located about 2 cm. After the start of the experiment, record the test tube to the test tube from Congo red paper turns blue start time is the thermal stabilization time. The basic theory of this experiment is that when the PVC at a temperature of about 170 ℃ when rapid decomposition, but with the addition of a heat stabilizer, suppresses the decomposition, with time, the heat stabilizer consumption occurs when the antimony oxide consumption is completed , PVC dramatically HCl gas decomposition in this case, the test tube as Congo Red reagent reacts easily with HCl and discoloration, will be immediately apparent, a note of the time determined by the length of time to heat stabilizer the effect of pros and cons. 2.2 Preparation of the static oven test in addition to thermal stability of PVC powder and other agents other processing aids (such as lubricants, impact modifiers, fillers, etc.) of the high-speed mixed sample. The sample must be taken, according to certain proportion of different thermal stabilizers, after mixing, add to the double-stick kneading machine for preparation of test pieces, generally without the addition of a plasticizer in the case, two roll temperature is set at 160 ~ 180 ℃, adding a plasticizer, the roller temperature is generally about 140 ℃. Tabletting using two stick repeatedly to obtain a uniform film after the backsheet, and clip, a certain size with different samples PVC heat stabilizer. Different PVC sheet placed in a test fixture, and then placed at constant temperature (180 ℃) of the oven at regular intervals (eg 10 min or 15 min), to record the color change of the test piece until the black so far. An oven aging test, can determine the thermal stability of PVC heat stabilizer effect to the merits, particularly ability to inhibit the color change is generally believed that, PVC heat, the color will occur white - yellow - brown - brown - black range from shallow deep changes, through a certain period of time to determine the color of PVC degradation. Torque rheometer torque rheometer is an imitation of the actual PVC processing of a typical small pilot-type apparatus. Outside of the instrument a closed processing tank, connected to the instrument by the computer can control the machining tank temperature, and within two roll speed, torque rheometer added quality of materials is generally 60 ~ 80 g, depending on the apparatus and different models. Experimental procedure is: be prepared in advance with different thermal stabilizer masterbatch, masterbatch formulations, in addition to base other than PVC general there ACR, CPE, 64 engineering applications 2011, Volume 39, No. 8 CaCO3, TiO2, lubrication agent. Torque Rheometer advance the set temperature, when the temperature rose to specify and steady speed, will be weighed mixture added processing chamber, quickly closed records on a computer connected to a variety of parameters, namely flow curve. After processing, you can also get different extrudate physical characteristics, such as whiteness, whether shaping, smoothness and so on. These parameters can determine the corresponding potential industrial heat stabilizers, heat stabilizers suitable shall have suitable torque and plasticizing time of the extrudate should be preferably molded and whiteness, surface smoothing. Torque rheometer in laboratory studies and between industrialized mass production to build a convenient bridge [24]. 2.5 blackened roll as a dynamic measurement test the effect of a thermal stabilizer class helper methods, dynamic rheometer double roll is used in the absence of experimental double-rolled sheet, select the instrument, which will be combined with high-speed mixed powder, pressed sheet forming, the resulting samples were subjected to repeated extrusion until the black test piece until completely black record time, the time is called blackening. Blackening by comparing the length of time to determine the type of thermal stabilizer effect of the thermal stability of PVC. 4 LDHs as PVC heat stabilizers research LDHs are a class of special structure and properties of inorganic crystalline materials, the typical structural features: ordered nanoscale laminates; has exchangeable interlayer anions; Shelf element according to the design requirements can be adjusted within a certain range; isomorphous substitution can also be introduced by other metal atoms, such as the host layer alkaline. Synthetic hydrotalcite with other thermal stabilizer compound as PVC heat stabilizer, can significantly increase the thermal stability of PVC, PVC material may also be given a number of other excellent properties, which is due to the hydrotalcite has a unique structure and properties. Huayou Qing [4] studied the Mg-Al hydrotalcite layered double hydroxides right through the base of PVC rigid and lightweight thermal stability, introduced the stabilizer coprecipitation synthesis method, and its X- ray diffraction analysis and thermal gravimetric analysis; results show that this kind of novel thermal stabilizer has important environmental value and economic benefits. Zhang Li [5] by colorimetry, pyrolysis studies hydrotalcite, lead salts, organic tin, as well as hydrotalcite and lead salts, organic tin compound stabilizers for PVC composite stabilizing effect, study the lead salt stabilizer system and hydrotalcite and organic tin compound stabilizer systems for PVC mechanical and rheological properties. The results showed that: hydrotalcite can not be the primary stabilizer of PVC, it should only be a secondary PVC stabilizer or stabilizer compounded with other compound stabilizers for use ratio of Mg 2 DLHs effect on the thermal stability of PVC most Jia, respectively, and lead salts hydrotalcite, organotin compound were carried out with good synergies and the latter better stability of PVC. Which, PVC, hydrotalcite and organic tin compound to 100:1.5:1.5 mass ratio of thermal stability of the composite system is not only superior to the conventional lead salt system, with good mechanical and rheological properties. Liu Zhiyuan [6] in the appropriate conditions, by coprecipitation synthesis of a series Mg-Al hydrotalcite products. Mg-Al-based hydrotalcite adjustable main characteristics of the chemical composition of shelves, first explores the Mg-Al-based hydrotalcite-doped calcium possibilities. The flame retardant and smoke suppression function of calcium into the main body of Mg-Al hydrotalcite chemical composition of laminates, laminates replace some or all of the magnesium ion, achieved through the experimental study of calcium magnesium aluminum layered product type three metaclasses and calcium aluminum hydrotalcite Bivariate Hydrotalcite synthesis. Using XRD, FT-IR on their composition and structure were characterized. XRD results that the samples are synthesized hydrotalcite layer structure, good crystal, high purity. IR analysis of samples tested synthetic interlayer anions are good symmetry of CO32-, further confirmed the Ca / Mg / Al Hydrotalcite successful synthesis. First studied as a flame retardant, heat stabilizer in PVC applications. Experimental results show that the Ca / Mg / Al hydrotalcite can improve the thermal stability of PVC. Under comparable conditions, MgAl-CO3-LDHs flame retardant and smoke suppression performance than Al (OH) 3 and Mg (OH) 2. At the same dosage (20phr) case, calcium magnesium aluminum type ternary Mg-Al hydrotalcite exhibited than hydrotalcite and hydrotalcite-type calcium aluminum better flame retardant and smoke suppression performance, indicating Ca2 + has improved materials flame retardant and smoke suppression effect.

PVC heat stabilizers thermal degradation and chemical principles

Thermal degradation of PVC industrial production mainly due to its molecular structure containing labile defects. Currently, the synthesis can not fundamentally improved methods and processes to avoid or reduce the generation of defects, so adding "thermal stabilizer" PVC improve thermal stability. In practical applications requiring heat stabilizers have a more comprehensive performance, any one of a single  Glycerol monostearate  component heat stabilizers are unable to meet. Thermal stabilizers actual synergistic effect on the development of composite system design principles, called compound heat stabilizer. Zinc-based composite thermal stability synergy: synergistic heat stabilizers "and in HCl", HCl and ZnCl2 concentration inhibiting growth weakened HCl catalytic thermal degradation of PVC, PVC to improve long-term stability; synergistic heat stabilizers and HCl protect the main stabilizing effect
Given agent, slowing consumption, thereby slowing the rate of PVC discoloration. Main effect of chlorine stabilizer instability suppression by replacing PVC heat
Degradation triggered not only suppressed discoloration of PVC, while also protecting the heat stabilizer synergist, slowing its consumption. PVC is one of the world's five common plastics in China, the first one of its consumption. China's economic development, especially the  azodicarbonamide development of urbanization and real estate, to make PVC building materials in China was a great opportunity for development, its demand substantial growth; addition, transportation, communications and other fields demand for PVC resin was rapid growth. PVC profile windows and doors for cold insulation, weather resistance and good corrosion resistance, environmental compliance, energy consumption than ordinary steel doors and windows can save 17%. China's total energy consumption of building energy consumption accounted for about 1/4, building insulation performance, energy consumption accounted for 50% of housing energy waste. Today's increasingly global concern for environmental issues to prevent climate warming, the application of different doors and windows will have new potential. Thermal stabilizer the  performance of the basic thermal stability, processing and weathering resistance. With the development of the plastics industry, and other performance additives accompanied exist, the optimized design of the "one package" of products are PVC heat stabilizers entered a mature stage of the landmark achievements. Balanced overall performance, cost-effective, environmentally friendly
Good, easy to customize and enhance production efficiency, "a pack" of composite stabilizer, is expected to be in the world
Generally welcomed, and become the future development trend.

plastic lubricant dispersant difference

 Lubricant is a broad concept. According to their different functions, the lubricant for the following three categories: (1) to reduce the friction between the particles to improve the  the materials, also known as  glidants); (2) to prevent the adhesion of raw materials to punch surface of the material, also known as anti-adhesion agent ); (3) to reduce the particle or tablet) with the friction between the die hole wall accessories, this is the real sense of the lubricant. An ideal lubricant should be both of the flow aid, anti-sticking and lubrication three roles, the  PVC heat stabilizer for window lubricant in the currently available yet no such ideal lubricant, are often one or two aspects of a relatively good performance, but other effects are relatively poor.
Type of dispersant fatty acids, fatty amides, and esters
Stearamide and used with higher alcohol can improve lubricity and thermal stability, the amount (mass fraction) 0.3% -0.8%, the slip agent may be polyolefin; hexenyl bis hard fat acid amides, also known as ethylene bis-stearamide (EBS), the lubricant is a high melting point, the amount of 0.5% to 2%; glyceryl monostearate (GMS), glyceryl tristearate (HTG); oleic acid 0.2% to 0.5% of the amount; hydrocarbon wax solid, mp 57 ~ 7
0 ℃, insoluble in water, soluble in an  azodicarbonamide organic solvent, the resin dispersibility, compatibility, poor thermal stability, the dosage is generally 0.5% or less paraffinic
Although the wax is external lubricant, but straight-chain non-polar hydrocarbon, not wet the metal surface, such as polyvinyl chloride resin that does not prevent adhesion of metal walls, only, and stearic acid, calcium stearate and used, in order to achieve synergy
(Nujol): Freezing Point -15 ¯ -35 ℃, the extrusion and injection molding processing, the compatibility with the resin
Poor, the amount added is generally 0.3% to 0.5%, too much time, but the processing performance deterioration
Microcrystalline wax: the petroleum refining process has been its relative molecular mass is large, and  there are many isomers, melting
Point 65-90 ℃, lubricity and thermal stability, but poor dispersion, the dosage is generally 0.1% to 0.2%, preferably butyl stearate, higher fatty acid and used
Metal soaps
Metal salts of higher fatty acids, called metal soaps such as barium stearate (BaSt) for a variety of plastics, an amount of about 0.5%; zinc stearate (ZnSt) for polyolefins, ABS, etc., the  Glycerol monostearate amount of was 0.3%; calcium stearate (CaSt) suitable for GE Plastics, external lubrication, the amount of 0.2% ¯ 1.5%; Other stearic acid soaps such as cadmium stearate (CdSt), stearic acid Magnesium (MgSt), copper stearate (CuSt) low molecular weight waxes
Based on a variety of low molecular weight polyethylene wax (homopolymer or copolymer), polypropylene, polystyrene or other polymer modified as raw material, by pyrolysis, oxidation from a range of performance of different oligomers
Its main products are: homopolymer, oxidized homopolymer, ethylene - acrylic acid copolymer, ethylene - vinyl acetate copolymer
Materials, low molecular weight ionomers five categories. Among the most commonly used polyethylene wax
Commonly used polyethylene wax average relative molecular mass of 1500-4000, the softening point of 102 ℃; Other specifications of polyethylene wax average relative molecular mass of 10,000 to 20,000, a softening point of 106 ℃; oxidized polyethylene wax of long-chain molecules with a certain amount of ester group or a soap, and thus the PVC, PE, PP, ABS and external lubrication more balanced, better, its transparency is good. As dispersing agent and its environment, many practical applications, selection of the appropriate dispersing agent is very important.

The synergistic effect of zinc borate

In the inorganic flame retardants, aluminum hydroxide flame retardant, smoke, filling three kinds of functions, because non-volatile, non-toxic, but also with a variety of substances produced synergistic effect, known as the inorganic pollution resistance flame retardants, but the use of aluminum hydroxide is usually necessary to add 50% (mass

Volume fraction) or more to show a good flame-retardant effect. Magnesium hydroxide and aluminum hydroxide in the case, this will add to the base resin due to the large deterioration of processability, mechanical properties losses. Antimony trioxide is an essential co-halogen flame retardant agent,

However, when used alone has little effect fire. Due to the higher zinc borate dehydration temperature (greater than 300 ℃), over most of the decomposition temperature of the polymer, antimony trioxide can be used in place of all or part of thermosetting polyester formulations, reduces the cost, but also

With aluminum hydroxide, magnesium hydroxide, and phosphorus-based flame retardants produce good synergistic effect, thereby reducing the amount of these additives, reducing their processing properties of the substrate.
In the study of zinc borate and magnesium hydroxide, aluminum hydroxide, antimony trioxide, chlorinated paraffin flame retardant in the low-density polyethylene Synergistion found zinc borate flame retardant flame retardant system with either complex or with the compound with halogen flame retardant system, can achieve good flame effect

Fruit, and reduce the amount of other flame retardants, to improve the processing properties of the material.

The basic purpose of zinc borate

Low-hydrated zinc borate according to its characteristics, mainly used in high-rise buildings of rubber parts, elevators, cables, wires, plastic sheath, temporary buildings, military products, plastics, TV housings and spare parts, marine coatings and synthetic fibers . In addition, boric acid

Zinc corrosion protection also has a unique and powerful cost-effective corrosion resistance, can be used as multi-functional inorganic anticorrosive pigment instead of toxic lead, chromium rust paint. It is released from the metal surface borate ion, ferrous metal surface adsorbed ions of oxygen in the air

Under the action of oxidation of iron ions, and borate ions form insoluble stable, dense, complex salts of the passivation film, to prevent rusting of metal. David M, Schuber also studied zinc borate flame retardant as a multifunctional mechanism of action of anti-corrosion paints and coatings in the various areas, as

The application domain. Study found that zinc borate flux can be used as a strong ceramic, suitable for low-temperature fast firing process. Billet, glaze slurry introducing zinc borate can improve the performance of the glaze firing temperature, significantly improve the quality of the product. In addition, prepared by high-temperature solid-phase reaction of boron

Zinc, the present study is more than can be used as the light emitting material Zn3 (BO3) 2. Therefore, zinc borate increasingly broad range of applications, along with its in new areas of research and development, some of the irreplaceable advantages have been demonstrated.

Low-hydrated zinc borate flame retardant mechanism

Into organic flame retardants and inorganic flame retardants organic flame retardants include halogen, phosphorus and halogen - phosphorus; inorganic flame retardants are aluminum hydroxide, antimony trioxide, magnesium hydroxide , zinc borate, etc. of the inorganic flame retardants, antimony trioxide greater consumption,

But because it can not smoke suppression also has some toxicity, and therefore its use is subject to certain restrictions. Currently, there has been non-flame retardant antimony technology trends, can replace some or all of antimony trioxide flame retardant mainly zinc borate, tin, zinc, molybdenum compounds, etc. According to statistics, the occurrence of

Deaths caused by fire, 80% of which is generated by combustion of materials caused by smoke and toxic gases, therefore, in addition to having excellent flame retardant effect, low toxicity, low smoke also its essential properties borate zinc as an environmentally friendly inorganic flame retardant, with

Non-toxic, pollution-free, flame retardant and smoke suppression of excellent performance, especially low-hydrated zinc borate (2ZnO3B2O33.5H2O) after the advent gradually been widely applied. Zinc borate and other flame retardants (antimony trioxide, aluminum hydroxide etc.) complex to use, can significantly improve their smoke suppression, resistance

Combustion performance, with good market prospects.
Low-hydrated zinc borate flame retardant mechanism
1.1 Physical Properties lower hydrated zinc borate as a white crystalline powder, melting point 980 ℃, density of 2.71 × 103kg/m3, refractive index 1.58, a molecular weight of 434.66, toxicity LD50 (oral, rat)>, no toxic inhalation and contact the skin, the eyes do not produce irritation, no

Corrosive; insoluble in water, soluble in hydrochloric acid, sulfuric acid and dimethyl sulfoxide, soluble complexes generate ammonia; insoluble in ethanol, n-butanol, benzene and other organic solvents; heated to about 290 ℃ begins to lose crystal water, to 600 ℃, completely lost crystal water.
1.2 retardant plastic pyrolysis release mechanism H, and R radicals, H and the active oxygen in the air to generate a great HO, the rapid expansion of the flame can, both the formation of chain reaction H (resulting pyrolysis) + O2 → HO + O CO (pyrolysis proceeds) + HO → CO2 + H Thus, flame retardants should reach

To flame purpose, you need to: ① to reduce the temperature of ignition, preventing polymer pyrolysis of H and R radicals; ② able to cut off the air; ③ able to capture the activity of great HO, prevent flame expansion.
zinc borate flame retardant as a flame retardant to satisfy the above requirements, the flame retardant mechanism is:
1 heat and diluted zinc borate can be higher than 300 ℃ crystallization of water, can play a role in the cooling heat. Zinc borate, about 38% of zinc oxide, zinc hydroxide, zinc or form into the gas phase, the combustible gas is diluted so that the combustion rate decreases.
(2) forming the cover layer generally halogen flame retardant zinc borate compound and use, contact with fire and heat, the reaction equation is 2ZnO 3B2O3 3.5H2O +22 RX → 2ZnX2 +6 BX3 + 11R2O +3.5 H2O ZnX2 high boiling point, is a solid substance that can combustible material covered on the table

Isolated from the air side, inhibiting combustible gases, and also to prevent oxidation and the action of heat; contribute PVC decomposes to form an aliphatic hydrocarbon, ultimately beneficial for the dehydration reaction; acid can promote the generation of large amounts of carbon of carbon increases means combustible material escapes reduction

Have a good smoke suppression effect.
3 to prevent chain reaction when added to the zinc borate halogen polymer material, in the combustion gas generated after entering BX3 encounter with water vapor to generate HX, the flame generated radicals halogen atom, to prevent free radical inter chain reaction.

Low practical application of hydrated zinc borate

In practical applications in the rubber ZB flame, to delay the ignition timing and the rubber a "self-extinguishing smoke" to prevent sustained combustion and spread of the plastic, resin production ZB retardant is added, can be made flame retardant plastic canvas, flame phenolics, unsaturated polyesters

Glass steel tile, plastic wire and cable protection cover, etc.. ZB retardants fine granularity, good dispersion, easy to grind modulated into paint, storage stability, in terms rust retardant additives have greater advantages than the existing [9] borate zinc and traditional flame retardant compound used can significantly raise

High performance flame-retardant and smoke suppression. zinc borate and antimony trioxide obtained when used PVC cable sheath, the oxygen index increased from the original 24 to 32 to 34. zinc borate flame retardant and antimony trioxide to (a ~ 3): 1 ratio to the halogen-containing resin, not only improve the flame resistance, and reduces with

Burning smoke halogen-free resin 25% of PVC containing 2ZnO3B2O3 3.5H2O carbides formed at 650 ℃ contains the original 80% boron, and 62% zinc, zinc catalytic dehydrochlorination of PVC, PVC cross-linked into the carbon layer, 2ZnO3B2O3 .5 H2O and halogen-containing materials such as bromine-containing polyesters,

Nylon, epoxy resins flame-retardant synergistic effect from [10]; it is in the non-halogen material such as ethylene - vinyl acetate copolymer, polyethylene, styrene, polyvinyl chloride, epoxy, acrylic, synthetic rubber and aluminum hydroxide can also play a synergistic flame retardant and smoke suppression effect, and

Filler can improve the performance of, inhibit dripping, to improve their mechanical properties .2 ZnO3B2O33.5H2O with Sb2O3 and Al (OH) 3 at the same time complex, can reduce the amount of Sb2O3, and better flame-retardant effect. Accordingly unsaturated polyester , epoxy resin, PBT, PET, PA, polysulfone,

Phenyl ether, ethylene - vinyl acetate copolymers, ethylene acrylate copolymers, polyethylene, ABS, polyurethane, polycarbonate, EPDM, acrylic very widely used in the silicone rubber, silicon-containing polymer in a single cable material 2ZnO3B2O33. 5H2O itself is an excellent

Retardant smoke suppressant