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How to prevent PVC products from compaction? What are the methods?

Although the factors affecting the PVC product compaction are very complex, but in the long-term processing practice. People also summed up some basic rules to prevent the concrete measures to reduce the pressure out as far as possible. What are the methods to prevent PVC products from compaction?

1, the addition of some pressure out prevention agent can prevent the phenomenon of pressure out. The addition of cationic or anionic surfactants often helps to reduce or reduce the pressure; The addition of stearic acid or zinc stearate based stabilizer, especially the liquid zinc stabilizer, can effectively reduce the crush. The addition of alumina, silica gel, triphenyl phosphite and so on can inhibit the action of pressure.

2, organotin stabilizer, whether used in a formula, no matter what kind of processing method, will not cause compression.

3. The surface state of the roller or screw has a subtle relationship with the compaction, so the surface of the roller should be kept smooth, and attention should be paid to preventing various foreign bodies and corrosive substances from damaging the surface of the roller or screw. When changing the formula, the processing equipment should be cleaned.

4. The formation speed of scale depends on the production speed of PVC products, the percentage of metal in the formula and the chemical form of the added metal.

5. Adjust the concentration of alkali earth metal stabilizer is an effective method to control the production of compaction. The dosage should be reduced to a lower limit under the premise of meeting the needs of stabilization. The partial or total substitution of alkali earth metals with alkali salt is beneficial to reduce the pressure out.

6, the use of stabilizer can reduce the pressure out. Barium stearate, calcium stearate, etc., can be used in conjunction with zinc stearate, cadmium stearate, etc., to effectively reduce the compression. In addition to zinc stearate and cadmium stearate, lead stearate and aluminum stearate can also be used.

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Do you know the method to make PVC pipe hardness better

Made of PVC pipe hardness is not up to, how to improve? Mainly from raw materials, formula consideration. See below for details:

1. The precipitation volume of the filling material (calcium powder) is best within 2.6-3.0. To give consideration to both hardness and tear strength, calcium powder as far as possible not more than 25. In addition, an appropriate amount of nano-calcium can be added to improve the strength.

2. The choice of stabilizer is very important. Stabilizer (lead salt stabilizer, calcium zinc stabilizer, etc.) should have good thermal stability, and internal and external lubrication balance and stability. Do not use too cheap stabilizer;

3. If the stability is not enough, a small amount of metal soap can be compensated;

4, the amount of CPE should not be too large, the amount of CPE will affect the hardness of the pipe; CPE should be selected with high molecular weight, standard chlorine content, no more than 35%, and no residue;

5, lubricant can not be used too bad, must be good, the worst use of PE wax. The total amount is about 1.5, not too much, so that when the product is deformed when the external force is encountered, the PVC molecular chain connection is not easy to be damaged;

6. CPE+ACR system, ACR+MABS system or CPE+MABS system can be selected for modification.

7, titanium dioxide will affect the tear strength, to choose fine.

According to the general dosage of calcium and zinc compound stabilizer in 100 parts (mass) PVC resin is 2.5 parts ~ 5 parts (mass) and the possible usage ratio of hydrotalcite in the compound system is 5% ~ 50%, the design investigates the influence of the dosage of hydrotalcite on the stability of PVC, it can be seen: The highest stable efficiency can be achieved when the amount of hydrotalcite in the calcium zinc complex system is 40% ~ 50% and the amount of hydrotalcite in PVC is about 3 parts (mass).

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Stabilization mechanism of PVC calcium zinc stabilizer

PVC degradation of various causes

1) thermal oxidation decomposition;

2) Increasing the cross-linking of large free radicals in the absence of oxygen;

3) the effect of structural planning on degradation;

4) Photodegradation;

5) Oxidation of HCl;

6) Radiation degradation;

7) Molecular chain breaking caused by the critical stress introduced in the processing process;

8) the impact of branching points in PVC molecules on degradation, etc.

Degradation of HCl from PVC

1) There are activated groups on the PVC chain, which is usually prone to the degradation reaction of HCl removal at more than 100℃;

2) The process of HCl removal is an autocatalytic process, which leads to chain decomposition and removal of HCl in macromolecular chains.

3) When 6 or 7 polyenes are present in a conjugated system, PVC molecules absorb ultraviolet light and thus appear yellow;

4) As the process of HCl removal continues, the double bond increases, the color of PVC continues to darken and even coking, crosslinking, and finally chain is broken.

PVC stabilizer should have the function

1) can replace the active and unstable chlorine atoms in the molecule, inhibit the dehydrochlorination reaction;

2) can absorb or neutralize HCl released in the process of processing and use, and terminate its automatic catalytic effect;

3) can double bond addition reaction with polyene structure, eliminate or slow down the discoloration of products;

4) capture free radicals and adsorption of ionic impurities, improve the activation energy of PVC HCl removal.

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Types of PVC processing auxiliaries and the causes of production upsurge

What are PVC processing auxiliaries? It is well known that for thermoplastic resins, the mechanical properties of the final product are closely related to the homogeneity of the polymer melt during the conversion process. Unlike most other thermoplastic resins, rigid PVC cannot be processed directly due to its inherent particle structure. It requires a long processing time at high temperatures, which often leads to thermal degradation. Processing AIDS bring many benefits to PVC resins, the main {HotTag} is related to the melting process and melt rheology during processing. Processing AIDS can improve the bonding force and homogeneity of melt, enhance melt strength, melt ductility and melt elasticity. The composition of the processing aid and its polymer structure will affect the compatibility of the aid with PVC and will change some properties, such as fluxing and lubrication properties. On the other hand, the molecular weight and molecular weight distribution of the processing AIDS play a key role in controlling the rheological properties of the melt. The most common processing AIDS are polymers of the methacrylate group. Polymethyl methacrylate (PMMA) type polymers have high glass transition temperature (Tg), and it has excellent compatibility with PVC materials, these properties are conducive to the generation and transfer of local shear heat, thereby promoting the melting of PVC during the melting phase.

In addition to the rheological properties of the melt, the main direction and goal of the research and development of the new processing auxiliaries are to improve the dispersion properties, improve the processing efficiency, and enhance the overall balance of various properties (especially the melt strength corresponding to viscosity). On the one hand, this development trend requires that processing AIDS can achieve the same effect with less amount, and on the other hand, in the application of uniform and transparent materials, it also requires that the materials are more easily dispersed and more uniform and transparent.

The global plastics industry is developing very fast, with an average annual growth rate of 4%~6%, which exceeds the growth level of global GDP. The main reason for this growth is that plastic materials continue to replace traditional materials such as metals, wood, and minerals. In fact, the various additives added to the resin are also very helpful for the successful application of plastic materials. Among the various types of additives used, polymer impact modifiers and processing AIDS provide the polymer with the most unique and valuable superior performance, while also improving the processing performance of the product. Toughening, rheological control, aesthetic appearance, machinability and economic factors are all important properties. A variety of these additives have been used for many years, after a long period of development derived from a wide range of varieties. One of the main reasons for this is the variety of emulsion polymerization processes, which allows scientists to continuously design suitable polymer components, polymer structure, polymer morphology, and polymer molecular weight/molecular weight distribution. Emulsion polymerization is very attractive for commercial production because of its low production cost and the ease of separation of the resulting emulsion products.

In 1956, the first polymer additive for emulsion polymerization technology was developed, which was a core-shell structure impact modifier prepared from methacrylate butadiene-styrene (MBS). Then came various acrylic processing AIDS and acrylic impact modifiers. Initially, these additives were used to improve the processability and toughness of polyvinyl chloride (PVC). The processing additives used for PVC are mainly {TODAYHOT} in order to promote the melting of PVC, improve the melt strength, improve the dispersion performance and surface quality. Ultra-high molecular weight processing aid is an important part of foamed PVC. With the help of processing AIDS, PVC foam can obtain a more uniform foaming structure, reduce the burst of closed foam and the foam density will be lower. Lubricating processing AIDS can effectively prevent molten plastic from bonding on the metal surface, improve the surface quality of products, and improve production efficiency.

There are many plastic materials that have very limited applications because they either do not have the required physical properties or because they have very poor processability. Processing AIDS are used to enhance the melt processability of plastics, increase production, reduce downtime and maintenance, and provide better product quality. In the 1950s, Rohm and Haas pioneered the development of the first commercially produced processing aid product for use in the production of rigid PVC. After this, this unprecedented technology was soon known by the industry, and thus triggered a boom in the production of PVC industry. Since the 1980s, such research and development has been carried out for other thermoplastic materials and polymer blends. The majority of processing AIDS are usually added to PVC, while very few are used in other thermoplastics (only 0.5%~5%). However, these processing AIDS can significantly improve the processing performance without significantly affecting other application properties. According to different functions, processing AIDS can be divided into fluxes, melt rheological modifiers, lubricants and dispersion accelerators. In fact, each kind of processing aid has more than one kind of effect. The function and application effect of any kind of processing aid depends on its chemical composition, polymer structure, polymer molecular weight and polymer matrix type.

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Detailed explanation of plasticization degree of PVC production process

1. Influence of plasticizing degree on product performance:

The performance of PVC products is closely related to the degree of plasticization, poor plasticization, brittle products, mechanical properties can not meet the requirements; Plasticization is too high, the product will appear yellow line, mechanical properties are not qualified, plasticization degree is very important in the process of PVC products.

1. When the plasticization degree is 60%, the tensile strength is the highest;

2, when the plasticization degree of 65%, the impact strength is the highest;

3. When the plasticizing degree is 70%, the elongation at break is the highest;

For the production of water supply pipe material plasticization degree of 60-65% is the most appropriate. Because in this range it can reflect the tensile strength and impact strength of the two properties.

2. The influence of temperature on plasticization degree:

The polymer material can not melt at less than 80℃ and is glassy. The material in the glassy state is hard and brittle, and the material can not be processed in the glassy state. When the temperature rises to 160℃, the material is in a high elastic state, but the material still cannot flow in this area, which can only make the material become soft and viscoelastic. Really can achieve PVC melt processing, and have mobility, the temperature should be between 160-200℃, but for any stabilizer, at a temperature higher than 200℃, long-term heat, the material and decomposition

So in the control of plasticization degree, the temperature can only be controlled between 160-200℃. In the temperature range of 40 ° C, PVC temperature set between 170-180 ° C, plasticizing is better.

3, improve the method of plasticizing degree:

1. By increasing the temperature of the fuselage and screw.

2. When the screw speed is normal, increase the feeding speed of the feeder to improve the plasticization degree

3. Increase the speed of the extruder when the rated speed of the extruder is satisfied with the feeding condition.

4. Give dry powder a good ripening period (12-48h)

Function of ripening period:

1, eliminate static electricity, reduce pollution

2, increase the apparent density

3, improve the plasticization degree

4, low molecular polymerization evenly dispersed, prevent extrusion instability.

5, by reducing the temperature of the confluence core to improve part of the plasticization.

4, how to judge the plasticization degree:

1, through the host current to determine the plasticization degree to (65/132 production line as an example, the host current to 46-52A is appropriate, because our company is low calcium products, to 45-50A is appropriate. The premise is that the screw speed is 16~22r/min, the feeding material is full and matched with the screw speed, the temperature setting is matched with the screw speed and the host current);

2, through the host vacuum exhaust hole to observe the plasticization degree of the material (that is, the material is filled with more than 60% in the middle of the screw edge and groove, the powder in the groove is in the state of bean curd residue and the bottom of the groove material is flattened);

3. The plasticization degree is determined by the viscoelasticity of the melt material of the die mouth (this method is more suitable for the start-up);

4. Determine the plasticization degree by the melt pressure and melt temperature of the confluence core (its disadvantage is that if the instrument fails or the confluence core sensor is pasting dead coke and other factors will affect the accuracy of the test results)

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Introduction to the role of PVC processing assistant ACR

Item description: ACR

ACR is an acrylicester copolymer, a core-shell copolymer. Compared with PVC molecules, its molecular weight is higher, generally about 1 million ~ 8 million (weight average molecular weight), true density is 1.05g /cm3 ~ 1.20g /cm3. It is prepared by various kinds of acrylic acid, crosslinking agent, emulsifier, initiator, molecular weight regulator and other raw materials, through multiple emulsion polymerization to produce white fine non-toxic, non-corrosive powder. For example,ACR-201 is a graft copolymer of MMA with an acrylate; ACR-301 is composed of MMA with EA and BA(butyl acrylate); ACR-401 is composed of MMA with BA, BMA(butyl methacrylate) and EMA(ethyl methacrylate).

Alias: PVC processing agent

Main ingredients: methacrylate, acrylate, etc

Properties: white powder, viscosity 0.2-13.5,40 mesh sieving rate > 99.0, apparent density 0.35-0.55, volatile < 1.5

The characteristics of

(1) Significant impact modification effect: higher impact strength at normal temperature and low temperature can be obtained by adding fewer copies.

(2) has a wide range of processing temperature.

(3) Low film expansion :ACR/PVC blend system export expansion is small, the product thermal shrinkage rate is low, the size is stable, suitable for high speed extrusion of profile.

Function:

PVC should be added in the process of processing PVC resin 1 % ~ 5 % of the processing aid,ACR is the most used processing aid, it is in extrusion, injection molding, blow molding, blister and calendering PVC main processing methods have been extremely widely used. For as processing aid ACR modified PVC mechanism, the consensus view is ACR via a long molecular chains in the PVC resin particles, pass the external heat and shearing force to resin, promote its melting and plasticizing, reduces the processing temperature, increase the melt strength, improve the quality of the appearance of the products, at the same time don't reduce the rigidity of rigid polyvinyl chloride (PVC).

1, with PVC has good compatibility, good dispersion, and PVC molecular chain entwined together, promote PVC melt plasticizing, effectively reduce PVC melt processing temperature, on the basis of small energy saving at the same time improve the weatherability of products;

2, can change the rheological behavior of PVC material melt, improve the fluidity of PVC material, so that it is easier to molding and extrusion, to ensure the stability of long time processing;

3, can improve the PVC material melt strength, avoid melt rupture, can solve such as sharkskin and other surface problems, improve the internal quality of products and surface gloss;

4. It can effectively prevent the pressure fluctuation and flow scars caused by extrusion and injection molding, and effectively avoid the surface problems such as ripple and zebra crossing.

5, can improve the surface gloss of products, due to the uniformity of plasticizing, and can help improve the tensile strength of products, impact strength, elongation at break and other mechanical properties;

6, can significantly reduce the PVC products of various additives such as stabilizer, pigment, calcium powder and other deposition on the surface of the products.

7, foaming regulator can effectively adjust the density and size of the bubble hole, can greatly improve the melt strength of PVC material, so as to effectively wrap the foaming gas, form a uniform honeycomb structure, prevent gas escape, make the product density drop;

8, good metal stripping, because it is a polymer material, not like a lubricant caused by precipitation and other problems.

9, improve the consistency of PVC product quality, such as appearance gloss, tensile strength, impact strength and elongation at break, etc

10. Effectively prevent surface defects such as silver wire due to pressure fluctuation and flow scars caused by extrusion and injection molding.

11, significantly reduce the deposition of various additives such as stabilizers, pigments, etc., on the surface of processing machinery.

Classification:

According to the different viscosity can also be divided into: low viscosity, medium viscosity, high viscosity; Low viscosity is 0.2-4.0 generally used with transparent films, sheets, etc.; Medium viscosity from above 4.0 to 11.0, generally used in profiles, pipes, pipe fittings, etc.; High viscosity of the general viscosity of 11.0-13.5, generally used for foamed board, foamed wood plastic, etc.

According to the role of different can be divided into: ordinary processing additives (such as HF-401, 175, 20, 801, etc.) and foaming regulator (such as HF-90, 901, 922, 921, etc.); In the domestic foaming regulator generally refers to the viscosity is higher than 10.0 or even higher than 11.0 acrylate processing AIDS, the reference dosage of 4.0-12.0 or more; Common processing AIDS include foaming regulator, lubricating processing AIDS and general processing AIDS. Reference dosage is 0.5-2.5 parts.

Interaction: can be used with stabilizers, internal and external lubricants, fillers, pigments, etc., better synergistic effect, and no adverse reactions.

Adverse reactions: the performance of the product was improved significantly when the product was used according to the dosage

Excessive use, the effect is not significantly improved, and even cause the melt strength is too large, the processing fluidity becomes worse, and the products become yellow.

Expiration date: one year (longer time can also be used, some performance slightly reduced)

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Types of PVC lubricants

 The main properties of commonly used PVC lubricants are as follows:

  (1) Calcium stearate

  White powder, melting point 148-155℃, non-toxic, excellent lubricity and processability, no vulcanization pollution, combined with basic lead salt and lead soap, can increase the gelation speed, the dosage is generally 0.1-0.4PHR.

  (2) Oxidized polyethylene wax

  White or light yellow powder or particles. Although oxidized polyethylene wax contains a small amount of polar groups, it is still incompatible with PVC, but it has high lubrication efficiency, which can improve the lubricity between polymer and metal, increase extrusion efficiency, and improve The dispersibility of the colorant gives the product good transparency and gloss. The dosage is 0.1-0.5PHR.

  (3) Stearic acid

  White or light yellow particles, melting point 70-71°C. Slowly volatilize at 90-100℃, used as external lubricant in hard PVC processing, the dosage is generally 0.2-0.5PHR, and has the effect of preventing chromatographic fouling, but if the dosage is too large, it is easy to bloom.

  (4) Glyceryl stearate

  Powder, melting point 85-87℃, has excellent heat resistance and fluidity, can increase the amount of filler, and can promote plasticization. Used together with waxes can improve the thermal stability of PVC-U. The general dosage is 0.2-0.6PHR.

  In practice, people have found that when two or more lubricants are used in combination, they have different effects from when they are used alone. In the formula of profiled materials, most of them adopt the compounding method

  (5) Paraffin

  It has a melting point of 57-63°C and does not contain polar groups. It is a typical external lubricant. Because of its low melting point, easy evaporation and low melt viscosity, it can only provide lubrication in a narrow range. It is suitable for single and twin screw extruders. The general dosage is 0.1-0.8PHR. This product has poor transparency and whitening easily.

  (6) Polyethylene wax

  White powder with a softening point of about 100-117°C. Due to its relatively large molecular weight, high melting point, and low volatility, it also shows obvious lubricating effects at higher temperatures and shear rates. It is suitable for single and twin screw extrusion of rigid PVC, the usual amount is 0.1-0.5PHR.

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How to eliminate bubbles

 (1) Physical methods

  From the perspective of physics, the methods to eliminate foam mainly include placing baffles or filters, mechanical stirring, static electricity, freezing, heating, steam, radiation, high-speed centrifugation, pressure and decompression, high-frequency vibration, instantaneous discharge and ultrasonic (acoustic) Liquid control), etc., these methods promote the gas permeation rate at both ends of the liquid film and the drainage of the bubble film to varying degrees, so that the stability factor of the foam is smaller than the attenuation factor, and the number of foams is gradually reduced. However, the common shortcomings of these methods are that the use is highly restricted by environmental factors, the defoaming rate is not high, etc., and the advantages are environmental protection and high recycling rate.

  (2) Chemical methods

  The method of eliminating foam from a chemical point of view mainly includes the chemical reaction method and the method of adding defoamer.

  The chemical reaction method is to add some reagents to chemically react with the foaming agent to produce water-insoluble substances, thereby reducing the concentration of surfactants in the liquid film and promoting the collapse of the foam, but this method has foaming The composition of the agent is uncertain, and the production of insoluble substances is harmful to the system equipment and other shortcomings. Nowadays, the most widely used defoaming method in all walks of life is the method of adding defoaming agent. The biggest advantage of this method is high foam breaking efficiency and convenient use. However, finding a suitable and efficient defoaming agent is the key.

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Union lubricants series product introduction

After molten polymers are usually has high viscosity, in the process of machining, the molten polymer through the slit, sprue runner, the polymer melt is bound to surface friction and processing machinery, some friction in polymer processing is bad, the friction melt fluidity is reduced, at the same time serious friction can make the film surface becomes rough, Lack of luster or streaking. Therefore, it is necessary to add additives for the purpose of improving lubricity, reducing friction and reducing interface adhesion. This is the lubricant. Lubricants in addition to improve the flow, but also can play a melt accelerator, anti-adhesion and anti-static agent, smooth agent and other roles.

Lubricants can be divided into external lubricants and internal lubricants. The role of external lubricants is mainly to improve the friction between polymer melt and the hot metal surface of processing equipment. It is less compatible with the polymer, easy to migrate from the melt to the outside, so it can form a thin layer of lubrication at the interface between the plastic melt and the metal. Internal lubricant and polymer have good compatibility, it plays a role in the polymer to reduce the cohesion between polymer molecules, so as to improve the internal friction heat generation of plastic melt and melt fluidity. Commonly used external lubricants are stearic acid and its salts; Internal lubricants are polymers of low molecular weight. Some lubricants have other functions. In fact, each lubricant has a role that can achieve a certain requirement, always internal and external lubrication, but in a certain aspect is more prominent. The same lubricant in different polymers or under different processing conditions will show different lubrication, such as high temperature, high pressure, the internal lubricant will be extruded out to become the external lubricant.

In the production of plastic film, we will also encounter some adhesion phenomenon, such as in the production of plastic film, two layers of film is not easy to separate, which brings difficulties to automatic high-speed packaging. In order to overcome it, a small amount of additives can be added to the resin to increase the surface lubricity to increase the external lubricity, commonly known as anti-adhesion agents or smoothing agents. In the molecular structure of general lubricants, there will be a long chain of non-polar and polar groups of two parts, their compatibility in different polymers is not the same, so as to show different internal and external lubrication role. According to the chemical composition, the commonly used lubricants can be divided into the following categories: fatty acids and their esters, fatty acid amides, metallic soaps, hydrocarbons, silicone compounds, etc.

Lubricants in the actual processing of plastics have a variety of performance, such as in mixing, calendering processing, can prevent the polymer stick to the cylinder, inhibit friction heat generation, reduce mixing torque and load, so as to prevent the thermal deterioration of polymer materials. In the extrusion molding, it can improve the fluidity, improve the adhesion between the polymer material and the cylinder and the mold, and prevent and reduce the retention. In addition, it can improve the appearance and gloss of the film.

From the point of view of processing machinery, the external lubricant plays an important role in mixing, rolling and enameling molding, and the internal lubricant is more effective in extrusion and injection molding.

The amount of lubricant is generally 0.5%~1%, and attention should be paid to the selection:

1. The flow performance of the polymer has met the needs of the molding process, then the main consideration of the role of external lubrication, to ensure internal and external balance;

2. Whether the external lubrication is effective should be based on whether it can form a complete liquid film on the plastic surface layer at the forming temperature, so the melting point of the external lubricant should be close to the forming temperature, but the difference between 10℃~30℃ can form a complete film;

3. Do not reduce the mechanical strength and other physical properties of the polymer.

When choosing lubricants in production, they should meet the following requirements:

4. High lubrication efficiency and lasting;

5. The compatibility with resin is moderate, the balance of internal and external lubrication; No frost spray, not easy to scale;

6. Small surface gravity, low viscosity, good expansibility at the interface, easy to form the interface layer;

7. Try not to reduce the excellent properties of the polymer, does not affect the secondary processing properties of plastics;

8. Excellent heat resistance and chemical stability, no decomposition, no volatilization in the processing;

9. Do not corrode the equipment, do not pollute the film, no toxicity.

However, the use of a single lubricant is often difficult to achieve the purpose, and several lubricants are needed in combination. In recent years, the development of composite lubrication is rapid. When choosing, the role of lubricants can be viewed from multiple angles.

Commonly used lubricants are stearic acid, butyl stearate, oleamide, ethyl bisstearamide and so on.

Many paraffin substances can be used as lubricants, such as natural paraffin, liquid paraffin (white oil), microcrystalline paraffin, etc., but their effects are different. Natural paraffin wax is used for external lubrication, can be used as a variety of plastic lubricant, release agent, the general dosage of 0.2~1phr, but its compatibility, thermal stability and dispersion is not very good, the dosage can not be too large, and the best with the internal lubricant; White oil is more used as internal lubricant of PVC and PS, with good lubrication performance and good thermal stability. The general dosage is 0.5 PHR. They are drug-free and can be used in food packaging. Another kind of microcrystalline wax: in plastic processing it is also used as a lubricant, the amount of 1~2Phr, thermal stability and lubricity than ordinary paraffin wax.

Low molecular weight polymers are also widely used as lubricants, such as polyethylene wax and low molecular weight polypropylene, which have good internal and external lubricity and are non-toxic. Polyethylene wax is suitable for PVC and other materials extrusion, calendering processing, the dosage is generally 0.1~1phr, can improve the processing efficiency, prevent film adhesion, improve the dispersion of filler or pigment, compatibility and transparency is not very good; Irregular structure low molecular weight polypropylene can be used as lubricant of hard PVC and PE. It has good performance and can improve the dispersibility of other additives. The dosage is 0.05~0.5 PHR.

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What are the differences between UPVC and PVC pipes?

Although both types are widely used, there are significant differences between UPVC and PVC.

Manufacturing process

In most cases, both types are made from the polymer polyvinyl chloride. However, manufacturers of these pipes can also mix various plasticizers into the mixture to make them easier to use. When these plasticizers are not used, the tubes are called UPVC.

attribute

The difference between UPVC and PVC piping also extends to attributes. Plasticizer used in PVC piping, phthalates are the most common. This and other plasticizers are odorless and colorless esters. When placed in PVC, they make the pipe produced easier to bend and more flexible by enhancing the overall flexibility. UPVC does not contain plasticizer and UPVC does not contain PVC BPA.

A plasticizer is produced when an acid reacts with an alcohol. Common acids include phthalic anhydride and adipic acid. Different combinations of alcohols, acids, and alcohols are used to determine the types of esters and plasticizers that can be made.

PVC is widely used to replace old iron and cement pipes in irrigation systems, waste water pipes and sink systems. Glue can be used to fix it, easy construction. UPVC is known for its resistance to chemical corrosion. It also helps to ensure an adequate flow of water, as the inner wall is smoother. It is harder than PVC, but is considered stronger, making it resistant to a variety of operating pressures and temperatures.

To deal with

The treatment of both types of pipes is roughly similar. Certain power tools for cutting PVC and plastic cutting hacksaw blades are suitable for both types of pipes. The difference between the two has to do with dimensional flexibility. For example, if the PVC is not precisely cut, its flexibility allows it to still fit well. However, in the case of UPVC, it must be cut to precise measurements, or it will not be used for the intended application. This is because it is rigid and does not stretch as lightly as PVC.

In construction, both types of plastic are used to make a series of pipes. For example, larger PVC pipes can be used to help move non-potable water. Another common use is in cables, where most PVC provides an additional layer of insulation.

In architecture, UPVC is an ideal alternative to wood in many cases. For example, it could be used to make window frames that are more durable and can hold components better than wood. Regular PVC cannot be used to create window frames. This is because UPVC does not decompose, but ordinary PVC does. Ordinary PVC is also not as resistant to skin as UPVC. For certain heavy drains and pipes, those engaged in construction work may also use this material instead of cast iron.

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What is the relationship between PVC film performance and plasticizer?

PVC film properties due to the use of plasticizer and different changes, and film properties and plasticizer chemical structure of the relationship. When a film is required to have a particular property, determining the formulation of the film is very complex, and some of the requirements for the film are sometimes contradictory. It is very difficult to make a film with good cold resistance and non-flammability. If oil resistance is required at the same time, the use of various plasticizers known at present cannot meet the requirements. Therefore, it is necessary to choose a proper proportion of plasticizer to make up the defects of various plasticizers by learning from each other so as to meet the application requirements.

In general, the plasticizer content of PVC soft film is 18 ~ 45%. When the plasticizer as a processing agent, adding less than 18%, we can see a strange phenomenon, that is, the content of this film is not soft than pure PVC hard film but more brittle. Its impact strength and cold resistance than pure PVC hard film is poor. This phenomenon may be due to the small amount of plasticizer, it is not possible to "eliminate" the polarity of the PVC molecules.

Films with plasticizer content less than 18 to 20% are mostly not made of pure PVC, but are often impache-resistant PVC, which is not brittle.

Films containing more than 45% plasticizer are difficult to manufacture because of their low strength, high elongation, and stickiness, so they are rarely produced.

The higher the plasticizer content of the film, the more obvious the influence on the film properties. In order to achieve the same softness, if the use of different plasticizers, the amount of the added is not the same. Contrast test in different films, often with the same hardness of the film as a benchmark, and not to the same plasticizer content of the film as a benchmark.

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How to choose each type of rubber plasticizer?

Polyol plasticizer

1. SBR vulcanized glue contains about 30% of the low molecular weight part which is not related to vulcanization. With the appropriate viscosity of rubber plasticizer to participate in the high relative molecular weight of SBR to replace the low molecular weight part, not only can adhere to the physical function of SBR vulcanized rubber, but also improve the processing function of rubber, together with the decrease in the cost of rubber production, increase the output of SBR. According to the material similar compatibility principle and the use and use of different occasions to choose rubber plasticizer, such as tire requirements excellent physical function, and do not contact with the human body for a long time, so it can be filled with aromatic rubber plasticizer.

2. BR, as the primary component of automobile tire compound, can also be used for the production of rubber tape, hose, etc. Generally, BR and NR can be used together to make rubber products have better physical function. Oil-filled BR not only has the characteristics of BR, but also improves the processing function and physical function of rubber material, and reduces the cost. The oil-filled BR used in the manufacture of tires can extend the service life of tires and advance the anti-skid function of tires. Naphthenic and aromatic rubber plasticizers can be used for BR oil filling. Generally, the oil filling mass fraction is 0.27 ~ 0.33, and the oil filling process is similar to SBR.

Paraffin-based plasticizer

3. The influence of rubber plasticizer on EPDM varies with the viscosity of the polymer and the type and dosage of the third monomer. Because the aromatic ring in the aromatic rubber plasticizer will absorb free radicals, it has an impact on the peroxide vulcanization, and is not easy to be used in the rapid vulcanization; The processing function of white wax base and high saturation naphthenic rubber plasticizer is excellent, which can give the vulcanized rubber higher tensile strength. Therefore, EPDM preferred to use white or naphthenic rubber plasticizer.

Naphthenic rubber plasticizer

4, the general viscosity of CR filled rubber plasticizer is to improve the processing function of rubber material. Due to the small amount of rubber plasticizer, there is no need to excessively choose the type of rubber plasticizer, generally use naphthenic rubber plasticizer. Cr is often used to make products resistant to oil or hydrocarbon solvents. Therefore, if a rubber plasticizer is filled with the same rate of increase in volume as an oil (or solvent) reaches swelling equilibrium in Cr, the volume of the resulting product will not change in contact with the oil (or solvent). High viscosity Cr can be added to a large number of fillers and rubber plasticizers, but the tensile strength and elongation at break of vulcanized rubber will decrease. Due to the large filling amount of rubber plasticizer, it is advisable to choose rubber plasticizer which is not easy to exudate and which has a large share of aromatic hydrocarbon carbon atoms.

5, NR has the following characteristics after filling oil: good softness, easy mixing processing; Good anti-wet slip function, can advance the wear resistance of the tire; However, the tear resistance function is decreased, and the permanent deformation is large. It is mainly used in the manufacture of snow non-skid tires. The physical function of NR vulcanizates with large oil content is obviously lower than that of general NR vulcanizates. The physical function of carbon black reinforced oil-filled NR vulcanizates after aging is better. For crystalline rubber like NR, assuming that the rubber plasticizer with large content of thick cyclic aromatic hydrocarbons is filled, it is possible to damage the crystallinity of the rubber molecular chain, so that the physical function of the vulcanized rubber is decreased; The use of rubber plasticizer with larger volume and smaller content of thick cyclic aromatic hydrocarbons has little effect on the crystallinity of rubber molecular chain, and the addition amount of rubber plasticizer can be increased. Therefore, aromatic or naphthenic rubber plasticizer is the primary choice for rubber plasticizer filled with NR.

As the composition of rubber monomer is different, and the type of rubber plasticizer corresponding to it is different. Using rubber plasticizer matching with rubber can make oil-filled rubber get the best physical function and reduce the production cost to the maximum limit. But along with the people to the health, the environmental protection request further advance, gradually changes to the high-grade, the pollution-free rubber plasticizer product is the rubber product production plant pays more and more attention to the problem.

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What are the advantages of foaming agent products?

There are two types of foaming agents, chemical foaming agents and physical foaming agents. Chemical foaming agent is decomposed at high temperature to form gaseous decomposition products (N2, CO2, NH3, etc.) organic and inorganic substances.

This decomposition process is usually exothermic and irreversible. Physical blowing agents can be liquids or substances that are normally vaporized. Physical blowing agents include aliphatic, hydrocarbons (pentane, hexane, decane, etc.). Chlorinated hydrocarbons (monochloromethane, dichloromethane, etc.). Chloro-fluorocarbons (trichlorofluoromethane, dichlorodifluoromethane, etc.), N2, CO2 noble gases and air.

Conventional physical foaming refers to the process of uniformly mixing the physical foaming agent with the resin matrix, and by changing the conditions during the operation, according to the principle of thermodynamic instability, the foaming agent is physically changed, and then the process of generating bubbles.

Chemical foaming agent is a gas generated by thermal decomposition or chemical reaction between raw material components. The gas released by chemical foaming agent when heated includes carbon dioxide, nitrogen, ammonia, etc.

The advantages of foam wood plastic panels

1. The loss is lower than that of wood: the use of wood-plastic board is less than the amount of ordinary wood used in the same situation. Moreover, wood-plastic panels are mostly hollow specifications, which can save more production materials. At the same time, the cost of hollow plates is also lower, and the price will be more favorable. Another advantage of the hollow profile is that it reduces its own weight and also reduces the carrying capacity of the load. These are the unique advantages of wood plastic panels, which cannot be achieved by ordinary wood panels.

2. Low maintenance cost: Ordinary solid wood panels need to be painted for protection, and some protective paint will be applied in subsequent use, otherwise the service life will be affected. The wood-plastic board does not need this process, it can be used after processing, no need to paint, and the waterproof performance is also very good. Maintenance costs are much lower than wood products.

3. Long service life: The service life of wood-plastic panels is three to four times longer than that of ordinary wood panels, that is, it can be used for 10 to 50 years more. The longer the service cycle is, the more cost-effective the wood-plastic board will be.

4. The product is environmentally friendly and can be reprocessed: wood-plastic board is ecological wood, environmentally friendly wood, renewable, and does not contain toxic substances. It can be processed. The product can be sawed, planed, bonded, fixed with nails or screws, etc. , the installation is very convenient.

5. Various colors of appearance: It has the natural texture of wood, and can also realize personalized modeling. The color of the product is diverse, and the use will not produce cracks, warping, deformation, and no knots of wood.

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What is wood plastic floor material?

Wood-plastic floor is a new type of green and environmentally friendly composite board that is mainly made of wood cellulose and plant cellulose as basic materials,thermoplastic polymer materials and processing aids, etc., and then heated and extruded by mold equipment,is a substitute for solid wood flooring, very suitable for garden landscape and other outdoor platform floor decoration.

What is the purpose of wood plastic floor?

Wood-plastic panels have good rigidity and toughness, and are the first choice for green and environmentally friendly panels in the furniture industry, interior decoration industry, packaging industry, vehicle and ship interior industry, and the future wooden house construction industry.

The advantages of wood plastic floor

1. Waterproof and moisture-proof: Wood floors are very sensitive to water and moisture. Excessive moisture may rot, expand and deform, while plastic wood floors are more prominent in waterproof and moisture-proof performance.

2. Anti-insect and anti-termite: Relatively speaking, the service life will be longer than that of traditional wooden floors.

3. Strong plasticity: Due to the variety of styles and colors of plastic wood flooring, it is suitable for various decoration styles and personalized modeling design.

4. Fire resistance: The plastic wood floor can effectively flame retardant, its fire rating reaches B1 level, it can self-extinguish in case of fire, and does not produce any toxic gas.

Disadvantages of WPC Flooring

1. Expansion and contraction are prone to occur: if the external temperature changes too much, the surface and interior of the plastic wood floor may expand, contract, and shape.

2. Wet and slippery: The plastic wood floor is easy to slippery in rainy and snowy weather.

3. The amount of antioxidants is too low and it is easy to fade: When purchasing wood-plastic flooring, please pay attention to the choice of the manufacturer.

The above is the relevant knowledge about wood plastic floor materials brought to you by Kunshan Union, I hope it will be helpful to you~

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What is the specific function of pvc plasticizer?

The processing of PVC products is inseparable from the participation of plasticizers. As an indispensable processing aid for PVC products, what is its specific role?

The role and performance of plasticizers in PVC: the performance of plasticizers in PVC, including compatibility with PVC, plasticizing temperature, plasticization rate, durability, etc.

PVC plasticizer

(1) Compatibility with PVC As the plasticizer of PVC, it must have good compatibility with PVC. Plasticizers with poor compatibility are prone to migration and precipitation from the surface of the product, which not only loses plasticizing effect, but also affects the appearance of the product.

(2) Plasticizing temperature The plasticizing of soft PVC refers to the process of forming a uniform material by melting with PVC. The plasticizing temperature is related to the type of PVC resin, the type and amount of plasticizer, and other additives in the formula. There are relationships. Generally speaking, plasticizers with good compatibility and strong solvation ability have lower plasticizing temperature.

(3) Plasticization rate, different types of plasticizers, in order to make PVC materials achieve the same hardness, the amount required is different. Based on the amount of DOP, other types of plasticizers need to achieve the same hardness. The amount is called the plasticization rate of the plasticizer.

(4) Durability, the durability of plasticizers includes volatility resistance, migration resistance, and extraction resistance. Generally speaking, the volatilization of the plasticizer is mainly determined by the molecular weight, and the migration is related to the compatibility of the plasticizer and PVC.

(5) Other properties, plasticizer properties, also include cold resistance, electrical properties, flame retardancy, mold resistance, etc.

Environmentally friendly plasticizer

The four-step plasticization theory of PVC: in the first step, the plasticizer enters the pores of the PVC resin particles; in the second step, the surface of the resin particle is swelled by the plasticizer, and at the same time, strain occurs inside the particle; in the third step, the first particle is swelled by the plasticizer Swelling, the plasticizer is dispersed among the macromolecules.

The first three steps of the plasticization process should be completed as far as possible during the powdering process. In the fourth step, the mixture of PVC, plasticizer and other additives is heated to a molten state to form a uniform soft PVC material, and the plasticization process is finally completed.

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Do you want to know the function and usage skills of foaming agent?

Foaming agent is a combination of aerosol technology and polyurethane foam technology. This adhesive usually needs to be stored in a dry and ventilated environment, as long as it is stored in a reasonable shelf life of up to 6 months. Excuse me, what is the function of foaming agent? What are the skills to use?

What is the function of foaming agent?

The foaming agent can decompose and form pores on the object of use, and different types of foaming agents have different specific effects. For example, glass foaming agent can reduce the glass brand design coefficient, enhance the mechanical strength of glass, and improve the use value.

Cement foaming agent can make cement have good air permeability and increase thermal insulation function. The plastic foaming agent can reduce the density of plastic and increase the thermal insulation of plastic products.

Polyurethane foaming agent can be used in construction, electrical appliance manufacturing and other fields. This foaming agent is a more environmentally friendly, energy-saving and low-cost adhesive. After use, it can play a better sealing performance, can also block water intrusion, good quality sound insulation, good flame retardant effect. Because the electrical appliance manufacturing industry has high requirements on the performance of foaming agents, it can cooperate with brand companies, such as Cosmore, to focus on the research of foaming agents, and provide customized foaming agent application solutions, which are widely used and can be applied to new Energy, military, medical, aviation, shipbuilding, electronics, automobiles, instruments, power supplies, high-speed rail and other industries.

What are the tips for using foaming agents?

1. Pay attention to the injection volume. The foaming agent has expansion characteristics. Pay attention to the amount used during the use phase. It can fill half of the required volume at one time. After curing, the edge can be supplemented with a larger foaming agent. Spray the required amount at one time, and after the foaming agent is cured, excess parts will overflow, and these excess parts need to be removed. It not only increases the cost input but also prolongs the construction time.

2, to prevent falling. When the foaming agent fills the gap, it should be noted that the uncured foam may fall and flow. Just after the foam is applied, it can be supported by wood, plastic, etc., and can be evacuated when it is semi-cured.

3. If it is a two-component foaming agent, it should be noted that the ratio is the weight ratio, and it needs to be fully stirred evenly.

The functions and usage skills of the foaming agent are the above. The construction of the foaming agent is more convenient, and it can be constructed manually or by machine. When the machine is under construction, you can buy products of the same brand, which can reduce machine wear and tear.

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What does calcium zinc composite stabilizer look at?

Calcium-zinc composite stabilizer is a common and commonly used heat stabilizer, so what aspects should calcium-zinc composite stabilizer see whether it is good or not? What kind of composition can make it play a big role? Where is this composite stabilizer suitable for?

What is calcium zinc composite stabilizer?

Calcium-zinc composite stabilizer is a composite heat stabilizer with calcium and zinc compounds as the basic components, and its appearance is powder, granular or flake. Manufacturing of PVC products, including food packaging materials, children's toys, medical products, etc.

Auxiliary reagents included

With the continuous advancement of technology and the development of one package, the composition of calcium-zinc composite stabilizer includes a certain amount of auxiliary heat stabilizer, lubricant, etc. in addition to calcium soap and zinc soap components. Among them, auxiliary heat stabilizers include: polyols, hindered phenol antioxidants, phosphites, epoxy compounds, β-diketones, nitrogen-containing compounds, certain inorganic compounds (such as hydrotalcite, zeolite, basic calcium aluminum phosphite, etc. ), etc.; lubricants include: hydrocarbon compounds, fatty acids, fatty acid esters, fatty acid alcohols, fatty acid amides, and the like.

Wide range of heat stabilizers applicable to the market

Calcium-zinc composite stabilizers have been widely used in the production of soft and semi-rigid PVC products for various processing processes including extrusion, calendering, injection molding, blow molding and plastisol. In recent years, due to the improvement of the application technology of auxiliary heat stabilizers, calcium-zinc heat stabilizers have been developed, and they are more and more widely used in occasions with high technical requirements. At present, calcium-zinc heat stabilizer can be used as a substitute for lead salt heat stabilizer in the production of wires and cables, pipes, pipe fittings, profiles, plates, etc.

Kunshan Union is an enterprise specializing in the research, production, sales and technical services of PVC processing auxiliaries, calcium zinc stabilizers, and rubber and plastic auxiliaries. The main products are: SPC processing aids, calcium zinc stabilizers, defoaming agents, foaming regulators, plasticizers, PVC lubricants, WPC processing aids. If you need it, you can pay attention to contact us to buy~