The Type of Lead Salt Stabilizer

Three basic lead sulfate, the formula is: 3PbO · PbSO4 · H2O, code TLS, white powder, density 6.4g / cm3. Three basic lead sulfate is a commonly used stabilizer varieties, generally with the two basic lead phosphite and use, due to non-lubricity and need to be equipped with lubricant. Mainly used for PVC rigid opaque products, the amount is generally 2 to 7 copies.

Two basic lead phosphite, the formula: 2PbO · PbHPO3 · 1 / 2H2O, code DL, white powder, density 6.1g / cm3. The thermal stability of the two basic lead phosphite is slightly lower than that of the three basic lead sulphates, but the weatherability is better than that of the three basic lead sulphates. Dibasic lead phosphite often used with three basic lead sulfate, the amount is generally about three basic lead sulfate lead.

Dibasic lead stearate, code-named DLS, not as three basic lead sulfate, two basic lead phosphite commonly used, with lubrication. Often with three basic lead sulfate, dibasic lead phosphite and the amount of 0.5 to 1.5 copies.

In order to prevent the toxic powder lead salt stabilizer scattering, serious pollution of the production environment, improve the dispersion effect of stabilizers, domestic and foreign has developed a dust-free composite lead salt heat stabilizer. The manufacturing process is:

Under the conditions of heating and mixing will have a synergistic effect of various lead salt stabilizer, auxiliary heat stabilizer and internal and external lubricants and other fully dispersed mixed into granular or flaky lead salt compound stabilizer. It will be added in a certain number of copies of PVC resin (no longer add other stabilizers and lubricants) that can achieve thermal stability and internal and external lubrication of the technical requirements.

There are information on the manufacture of clean lead salt composite stabilizer, the use of lead salt stabilizer particles fine, and thus the surface area with hydrogen chloride increased. And with the internal and external lubricant compound, so that the dispersion of good, heat stability efficiency is significantly improved, the amount can be reduced.

Effects of calcium stearate and stearic acid on the lubrication of paraffin and PE wax

Calcium stearate (CaSt₂) and stearic acid (HSt) in the formula in the presence of paraffin, PE wax conditions can effectively promote the resin plastic and reduce the melt viscosity, so they play from the internal lubrication, are internal lubricants. And in a certain range, the plasticizing time and the plasticizing torque decrease as the CaSt₂ and HSt additions increase.

In the absence of any additives to promote the plasticization of lubricants, only adding delayed plasticized paraffin, PE wax, according to common sense inferred that its plasticization time should be added to promote the plasticization of CaSt ₂ and HSt even longer, but the result is Than any addition to the internal lubricant CaSt ₂ and HSt plasticization time are shorter! It is recognized that the external lubricant mechanism of action: the external lubricant evenly coated outside the PVC particles, so that particles are easy to slide each other, reducing friction and delay the plasticization. But the question is whether it can be completely evenly coated on the PVC particles. Do not use the internal lubricant, only the use of external lubricants can not completely even cover all the RPVC particles, is due to paraffin, PE wax composition of the outer lubricating film tear strength and adhesion strength to the matrix is ​​too small, easy to heat And shear damage caused by. Reason: on the one hand paraffin, PE wax outside the lubricant itself is a non-polar material, between them there is only a small force of the dispersion force (non-polar molecules close to each other, their instantaneous dipole moment will produce very Weak attraction), because the anti-tear strength of the lubricating film is small; on the other hand, the interaction between the polar resin molecules is much greater than that between the non-polar paraffin and the resin (interfacial tension) Together, accumulate in the local part of the resin, and thus can not even wet all the resin particles, so that the role of lubrication.

If there are CaSt₂ and HSt in the system, the polar groups are interconnected with the polar nodes on the surface of the PVC particles, while the non-polar long-chain alkyl moieties are wetted and coated The paraffin liquid film on the surface of the resin particles is miscible (similar to each other), and the wetting layers of adjacent paraffin layers can be thinned and diffused with each other. Polar internal lubricants like "rivets" as paraffin, PE wax wetting film evenly fixed on the metal surface and PVC resin particles on the surface. This "rivet" effect improves the strength of the paraffin, PE wax outside the lubricating film against high shear, maintains the integrity of the lubricating film, thereby delaying the plasticizing time more effectively than using only the external lubricant , And reduced the plasticizing torque.

Therefore, the internal lubricant can not only promote the plasticization, reduce the melt viscosity, and in combination with the external lubricant, and the external lubricant has a better synergistic effect, it can enhance the role of late lubricant lubricant lubrication.

Added: calcium stearate lubrication is stronger than stearic acid.

CPE to price increases

Tension supply

The recent special material prices rose 500 yuan, up 600 yuan of chlorine, the main raw material cost increases more; in addition, CPE raw materials of anti caking agent, light calcium prices also rose more; affected by environmental factors, CPE raw materials of anti caking agent, light calcium, chlorine and so on not only rising prices, and tight supply, in the face of many CPE manufacturers of raw materials stock situation, due to limited raw material, individual manufacturers have not received single letter, resulting in CPE supply difficulties, promote the rise. Shandong area by environmental influence, a large number of CPE company production, according to industry through the leakage current operating companies are not more than 10, and the home Limit production, supply extreme tension

In summary

Between August and September, the CPE rally has become a foregone conclusion, and the increase will be slightly faster, not only price increases, supply is also unsustainable

Quality control of PVC profile and detection of PVC material

1、PVC inspection of raw materials

The quality of raw materials directly affects the performance of the profiles and the quality of the finished doors and windows，Therefore, the choice of raw materials、testing,、warehousing and use of such links should be checked

1-1、Selection of PVC raw materials

According to the requirement of product formulation，Production capacity of PVC raw material suppliers、Delivery capability、product quality、Reputation and quality assurance system for investigation、Analysis，Selection of large, quality assurance manufacturers

1-2、Inspection of raw materials

In accordance with national standards, industry standards, enterprise standards, various raw materials testing items and methods

1-2-1、Detection of PVC

PVC is the main raw material，Linking all kinds of PVC auxiliaries，And give the specific properties of PVC Profiles,Often choose PVC - SG5(SUPER GRADE), that is the average degree of satisfaction is about =1000, and the K value is 67,To make the parts glass temperature (Tg) moderate, hot forming processing suitable, good mechanical properties, low temperature resistance. The molecular weight, viscosity number, {(ml/g), (g/ml)}, resin particle size and distribution, residue, volatile content and impurity particle number of PVC resin were tested.

1-2-2、Detection of Titanium dioxide (TiO2)

Rutile titanium dioxide is the ideal coloring agent for white plastic windows，It also has the function of shielding ultraviolet rays (UV) and infrared rays，It can improve the weather resistance and heat resistance of parts，Rutile type titanium dioxide is a cube structure, titanium and oxygen atoms arranged closely, the crystal structure is stable, high density (4.26/cm3), refractive index, titanium dioxide particle size influence the surface quality of the products, mechanical impurities in titanium dioxide, during melt processing can accelerate the catalytic dehydrogenation, PVC. The dehydrogenation reaction caused by PVC degradation and discoloration. Therefore, the mechanical impurities, sieve residues, appearance and volatile content of titanium dioxide should be taken as important quality standards.

1-2-3、Detection of chlorinated polyethylene (CPE 135A)

CPE is a PVC impact modifier，The addition of CPE is designed to enhance the impact resistance of rigid PVC profiles and resist external force damage during the installation and use of doors and windows. CPE does not contain double bonds in its molecular structure. Good weatherability and good stability of light and heat for PVC profile. The presence of hydrogen atoms makes CPE polar and increases the compatibility with PVC. The miscibility depends on the chlorine content in the CPE and the distribution of chlorine atoms on the PE backbone (represented by residual crystallinity). As a modifier of PVC, CPE with chlorine content of 36%-38% is good. It not only has good elasticity and compatibility, but also has low crystallinity, low glass transition temperature and good comprehensive properties. The main test items are chlorine content and residual crystallinity, apparent density, tensile strength, volatile content, decomposition temperature, etc..

1-2-4、Determination of light calcium carbonate (CaCO3)

In order to reduce costs, improve rigidity and heat resistance, improve weather resistance, increase dimensional stability and be favorable for extrusion and molding, a certain amount of lightweight CaCO3 is often added. The content of CaCO3 in light calcium carbonate residue on sieve fineness, has an important influence on the physical and mechanical properties of products and product appearance, it is the main index, the second test appearance, volatile content, acid insoluble content have requirements.

Concluding remarks：Production enterprises must strengthen the management system, establish and improve the quality management system, strictly implement the relevant standards of the state or enterprises, and strive to improve product quality and achieve sustainable and healthy development of the industry

PVC Stabilizers Rise Rapidly, Have You Made the Stabilizer in Advance?

1、Lead price inflation，Stabilizer costs go higher

For nearly half a month，Lead price stability，Only a little increase，Hovering around 17500 RMB/TON,The price of lead went up sharply last week,First break through the 18000RMB/TON,Followed by day 550RMB/TON rose to 18600 RMB/TON,The price of lead continues to go up this Monday,The cost has gone up sharply,Is bound to drive up the price of PVC stabilizer

2、The price of Stearic Acid is soaring，It is also the reason why the cost of PVC stabilizer increases

The price of Stearic Acid has risen by nearly 1000RMB/TON in the past two months,As a necessary PVC composite stabilizer raw materials,Further drive up the price of PVC stabilizer

3、Environmental factors，Manufacturers operating rate is low

Due to environmental investigation，The overall industry operating rate is low，Causing tight supply throughout the industry，Further push up prices

In summary:

The price of Lead Salt PVC compound stabilizer and Hard Salt Stabilizer will be raised continuously in the near future,Demand customers must make inventory reserves in advance.

Brief Analysis of The Application of ACR and CPE to UPVC Tubular Product

In terms of the use, UPVC (unplasticized polyvinyl chloride) pipe can be mainly divided into water supply pipe, drainage pipe, pipe for chemical use and etc. The characteristics of structure divide them into solid-wall pipe, corrugated pipe, foamed pipe and etc. The fact that different pipe products need various product standard and technical index causes the unlike producing formula and technique. No matter which pipe product, all the materials within the cost of determined formula are expected to have anticipated mechanical strength ( strength of extension, anti-impact strength), a good outside finish, better weather resistance, wonderful thermal properties and less thermal deformation. All the above performance index are measured through hydraulic test, falling weight impact test, Vica softening test, longitude shrinkage test and etc. 

CPE and ACR are chiefly involved in the production of UPVC, so this article will talk the specific application effects on perspective of the effects of CPE and ACR to the improvement of performance index of UPVC pipe. ACR ( Acrylic copolymer) , a kind of acrylic emulsion copolymer with core shell structure , is a comprehensively excellent impact-resistant modifier of PVC.

Hydraulic test

In regard to the UPVC pipe for water supply and chemical use, the most different thing of the material product  can be whether the hydraulic test achieve the standard or not. In general, two situations will occur if the test fails to reach the expected standard. The first one is that the pipe materials crack without apparent deformation( increased diameter); The second one is the pipe cracks with apparent and visible deformation. The first situation is called brittle fracture that pipe experiences abrupt tearing fracture and the second one is ductile fracture that pipe materials firstly experience deformation of shape ( increased diameter), then gradually enlarged deformation and lastly crack to be a seemly shape of the vase and a certain period is remained between the deformation and the final fracture.

According to force analysis of plastics pipe under the static hydraulic pressure (P), a relational expression (referring to GB/T6111-2003) among the hoop stress of wall thickness (tensile strength) , external diameter and wall thickness:

In the relational expression, P (Mpa) stands for the hydraulic test pressure; δ means the determined hoop stress ( tensile strength, MPa); dmin（mm）is the measured mean outside diameter; emin（mm) is the minimum wall thickness of measured free length.

For the UPVC pipe of specified product standard and pressure rating, the dmin、emin in the above relational expression is known number, therefore, the hydraulic test pressure of pipe materials in the same size is determined. However the anti-pressure ability of pipe depends on δt which means the strength of extension of pipe materials. Namely, pipe will pass the hydraulic test if δt > δ, or it may crack. Pipe with brittle fracture reveals a lack of tenacity, which usually fails in the falling weight impact test. Here a question appears that which factor the strength of extension is related to?

(1) Firstly, the strength of extension relates to the molecular weight of PVC resin. More molecular weight the resin has, the stronger the strength of extension will be. Secondly, it closely connects with the molecular structure of PVC resin. Generally, the structure of PVC molecular chain mainly is “head-tail”, which is the most stable. Because of the process control, there are possibilities for the “head-head” and “tail-tail “structures which reveal less stability than “head-tail” structure. Besides, some branched chains with double linkage may appear due to disproportionation. These branched chains can easily experience decomposition and are called defect structure. The more defect molecular structure it has, the less strength of extension it indicates

(2) The materials included in the product formula of UPVC pipe such as the composite heat stabilizer, lubricating agent, impact modifier, filler (light calcium carbonate) and etc. will lower the strength of extension of PVC pipe materials at different degrees.

(3) The composition of various materials of UPVC pipe results in that only uniform mixing and gelatin and fusion of  all parts can generate excellent strength of extension. Only if the extruder obtains sufficient shear force can it be realized. Obviously, if the formula of PVC resin and UPVC is determined, the degree of plasticification of pipe materials may influence the strength of extension of pipe materials. Actually, it is the main reason of the unsuccessful hydraulic test for many manufactures.

 Admittedly, the improved technological conditions such as the reasonably raising technological temperature ,may occasionally contribute to the plasticification of PVC resin but it may lower shear force for extruder with bad plasticizing effect. Besides, because of the easily decomposition of PVC resin, raising processing temperature always lead to the decomposition of PVC materials and bring a series of problems such as process variations, increasing rejection rate, more demand for stabilizer. In fact it is not beneficial for the stable product quality and may increase the producing cost.

 In order to achieve the most desired plasticification of PVC resin, it is a best choice to add enough ACR processing agent (such as HF-100、HF-401) . To realize the improvement of PVC degree of plasticification at lower processing temperature, it can lift torsion and enlarge shear of force so as to further improve the strength of extension, perfect the degree of finish, and accelerate the mobility of melt. Moreover, it can lift the productivity and lower the rejection rate and better balance the process control. Comprehensively, supplement of sufficient ACR processing agent actually lessen the producing cost.

 There are several factors accounting for the failure of plasticification. More light calcium carbonate , filler and so on can both hinder the processing procedures. Hence , necessary lubricant are needed but more lubricant may produce the slipping of materials. Under this circumstance, PVC mixtures can hardly achieve the needed degree of plasticification without a certain amount of processing agent. In the meantime, adding of light calcium carbonate, fillers bring in the reducing of mobility, raising backpressure and lessening of productivity. In this situation, processing agent ACR can not only accelerate the plasticification of materials but also improve the mobility of materials at the same time. Degree of plasticification closely connects to the shear force of machines. The passing of service life may widen the gap of screw and charging barrel, bring down the shear force and degree of plasticification. At this time, it is needed to add more processing agent, adjust the degree of plasticification to a proper degree and perfect the mobility. Dichloromethane impregnating experiment can be conducted to test if the degree of plasticification achieves the standard.

Considering the information mentioned above, some other factor may influence the strength of extension of UPVC pipe materials. Impact modifier cannot be neglected.

CPE and ACR are the dominant members among all the impact modifiers in the application of pipe materials. Several experiences from many manufactures prove that with extrusion formula, adding of CPE reveals worse strength of extension than the adding of ACR. The results of experiments prove that using 6 portions of ACR instead of 10 portions of CPE may lift the strength of extension by 10% with the same or slightly higher impact strength.

Drop-weight test

Drop-weight test, an important index of the application of pipe products, intends to measure the impact resistance of pipe materials. The main reasons of the impact resistance below the mark are as follows:

①Degree of plasticification of UPVC pipe materials

 Degree of impact resistance also connects to the degree of plasticification just as the strength of extension does and displays more influence to the degree of impact strength. The pipe materials without better degree of plasticification are easily cracked and cannot pass the drop-weight test. Just as mentioned above, it is a vital choice to add sufficient amount of ACR processing agent (such as HF-100、HF-401) to improve the plasticification of materials.

 ②. the performance , amount and dispensability of impact modifier

Brittleness is the shared characteristic of PVC resin, hence some impact modifiers are expected to added to increase the degree of impact resistance. The efforts of impact modifiers greatly rely on its  the performance, amounts and dispensability. It is proved that ACR has better impact resistance than CPE. With the same basic formula, only more amounts of CPE can achieve the same degree but with less amount of ACR. Besides, there are different impact resistance mechanisms between CPE and ACR. ACR are globularly scattered in the PVC materials and depends on the shear zone and crazing to abort energy so as to realize the impact resistance. In order to achieve this goal, it also greatly depends on the dispensability of ACR besides the dependency on structure of ACR. ACR is made of countless spherical particles and can easily crack into smaller spherical particles and disperse in the basic materials with the working of high mixing machine and screw shearing. CPE particle consists of ten billion of linear CPE molecules twisting with each other, which cannot disperse evenly in the PVC. Foreign high extruder rarely adopts CPE as impact modifiers but adopts ACR. With the high efficient extruding condition, piling phenomenon of CPE in the PVC can influence the actual impact resistance efforts but also bring uneven basis materials and greatly reduce the tensile strength in some areas. It easily cracks in the hydraulic pressure test of UPVC and the application of pipe materials.

Obviously, ACR can use a slightly add to reach better degree of impact resistance and exerts less influence on the degree of impact resistance of PVC, which is the incomparable features for CPE.

Vica softening point

Vica softening point represents the thermal properties of plastic materials. Materials with high vica softening point reveal less thermal deformation and strength at a raising temperature than the materials with low vica softening point. Therefore, many plastic products all determine the vica softening standard of materials with the aim of guaranteeing that products won’t deform and lose its strength and then abandon its application performance within the determined application range.

With the determined PVC resin, impact modifier mainly influences the vica softening point. CPE and ACR of resistance all belong to rubber elastomer with a tendency to reduce the vica softening point of PVC products. CPE is of “sea-island” structure.  But the modular structure of ACR exerts difference with the linear CPE as the“core-shell” structure , which won’t have apparent impact on vica softening point as the CPE does. This is the reason why a majority of manufacturers primarily choose ACR as impact modifier.

 Longitudinal shrinkage rate represents the longitudinal size changes from a high temperature to a low temperature. If the longitudinal shrinkage rate exaggerates, pipe materials will produce great internal stress due to the lessening temperature. The internal stress overlays with other stresses may accelerate the destroy of materials. Long laying pipe lines may lead to the unplugged pipe line because of the phenomenon of “thermal expansion and contraction when cold” without backfilling. According to the experiments, less necessary amount of ACR in the UPVC pipe materials than the amount of CPE make it less influential to longitudinal shrinkage rate. Besides, longitudinal shrinkage rate is closely connected to mold matches and processing control.

Metachromasim and strength decrease property are two aspects of the weather resistance of UPVC pipe materials. It is obvious that the metachromasim closely relate to the outside appearance and the latter influences the service life of materials. There do exist the same problems in the door and window profiles and other products. In regrading to the current weather resistance tests and massive experiment results, ACR reveals unparalleled weather resistance and the application of ACR displays postponing potential economic benefits.

Melt strength

 During the processing, the melt strength of UPVC exerts apparent negative effects on the highly filled light calcium carbonate and other fillers. With more fillers , decreasing melt strength , the melt fracture phenomenon easily appear and form surface defects with the coordinate working of high shear and traction. It finally leads to the decreasing mechanical property of UPVC materials. Thanks to large amount of modular particles and good compatibility, ACR can contribute to the improvement of melt strength so as to get high strength UPVC products. In general, it is advised to add 1.5-3 portion of ACR to match 1-2 portions of ACR during the production of UPVC. Then a comprehensive excellent UPVC product can be get. With the people’s deep exploration of PVC on its toughening modification, more new method and thoughts will spring up to make PVC resin widely used among all the fields.

Strict Enviromental Supervison In China Effect the Chemical Enterprises

For the enviroment of the motherland, samll and medium-sized enterprises in Shandong: 317 are closed, 140 are moved, 54 enterprises signed a relocation agrement, 1,631 enterprises are power off. According to the plan, 2,577 unqualified enterprises will be closed next month.

In Beijing and Tianjin: 623 enterprises are closed, 265 are moved, 4,263 are powder off. According to the project, all unqualified enterprises will be closed before October.

Behind enviromental protection hiding the tide of rising prices will begin.

Under such struct enviromental supervion in China, please cherish the supplier who still deliver on time.

Shipping CPE, ACR and PVC Stabilizer

One 40GP Container is shipping to export. Including 16Tons CPE, 5 Tons PVC Stabilizer and 4 Tons ACR.

And recently we advise our client if you wonder to purchase the PVC Resin, you should place the order as soon as possible. The price of PVC Resin is stiil on the up trend.