Plastic profile products are mostly used:Window frame、Stair handrail, trunking, skirting board, profiled pipe, etc.raw materialMainly hard PVC, a few semi hard PVC, soft PVCpolyurethaneLow foaming and other materials.
Plastic profileDue to the huge market demand and broad development prospects, products have developed rapidly in China in recent years. Due to the fierce market competitionPlastic machineryAll manufacturers consider how to improve the productivity and qualification rate of plastic profile products under the premise of ensuring product quality, so as to give full play to the maximum capacity of equipment and reduce the production cost of products.
With the growing competition in the plastic profile industry, mergers and acquisitions and capital operations among large plastic profile enterprises are becoming increasingly frequent. The domestic outstanding plastic profile manufacturers are paying more and more attention to the research on the industry market, especially the in-depth research on the change of enterprise development environment and customer demand trends.Because of this, a large number of domestic excellent plastic profile brands have risen rapidly, and gradually become the leaders in the plastic profile industry!
Plastic profiles are mostly used:Window frame、Stair handrail, trunking, skirting board, profiled pipe, furniture, building materials and other accessories.The raw materials are mainly hard PVC, and a few are semi hard PVC, soft PVC, polyurethane low foaming and other materials.
For rigid PVC plastic profiles, there is a disadvantage of poor impact resistance. They are often modified by adding ACR, CPE, EVA, MBS, etc. to improveImpact strength。CPE（chlorinated polyethylene ）EVA (ethylene vinyl acetate copolymer), ACR (acrylic ester), MBS（Methyl methacrylate-Butadiene styrene graft copolymer) is generally added 6%~10%.MBS is mainly used in transparent plastic profile products, EVA should notLead stabilizerSharing, when sharing, the forming processability is poor, and the powder spot is easy to form. It is better not to share CPE with zinc stabilizer, and the low temperature property of CPE is not very good.
When producing plastic profile products, process conditions such as temperatureScrew speed, traction speed, etc.
Introduction to additives
Announce
edit
Plastic profiles are listed as one of the key building materials in China due to their excellent thermal insulation performance.stayPlastic Profile In the production process, what problems should be paid attention to to ensure the quality and process of the profile.Now let's know what plastic profile additives are?
Impact modifier
If not added in the production of plastic profilesImpact modifierThe plastic profile will be very brittle and hard, and will be easily broken with slight impact.The impact modifier commonly used in the production of plastic profiles mainly includes the following three categories:chlorinated polyethylene , polyacrylateEthylene vinyl acetate copolymer。
heat stabilizer
Plastic profiles are heat sensitive plastics, so heat stabilizers are essential in the production and processing of plastic profiles.The metal salt in the heat stabilizer can absorb HCL decomposed from PVC, so it can slow down the decomposition rate of plastics and extend the decomposition time. The most commonly used compound lead salts in the production of plastic profiles have high heat stability efficiency and low price.
lubricant
The main function of lubricant is to reduce the mutual friction between polymer and processing equipment and between polymer internal molecules, prevent resin degradation caused by excessive friction heat, and improve the efficiency of heat stabilizer.
Processing aids
Processing aids are mainly used to improve the processing properties of plastics.The processing temperature of plastic profile is close to the decomposition temperature, and the fluidity is poor, so it is easy to stick to the equipment for coking. Therefore, a certain amount of processing aids need to be added in the production of plastic profile to overcome the defects of the plastic profile itself.
Light stabilizer
Light stabilizerIt can inhibit the photooxidative degradation reaction of polymers by shielding and absorbing ultraviolet rays, quenching excitation energy to capture free radicals, etc., so as to give products good light stability effect and extend their service life.
Filler
Filler is a solid additive different from plastics in composition and structure, also called filler.It has obvious effect and economic value on improving some physical and mechanical properties of plastics and reducing the cost of plastics.Adding filler in the production formula of plastic profile can reduce the size change rate of plastic profile after heating,Impact strengthIncrease the rigidity and reduce the production cost.
Causes of nonconforming products
Announce
edit
In the production process of plastic profiles, due to improper formula or unreasonable plastic processing technology, the plastic profiles become brittle. The main characteristics are: chipping and cold punching fracture during blanking.Qingdao Plastic Machinery provides the reasons for the poor physical and mechanical properties of plastic profile products.
The first reason for the brittleness of plastic profiles: the formula and process are unreasonable during the production of plastic profiles
Excessive packing
Because the price of plastic profile is reduced and the price of raw materials is increased, many manufacturers reduce the quality of plastic profile products while reducing costs. Due to the composition of the formula, the most direct and effective way is to increase the filler. The filler commonly used in the production of PVC-U plastic profile is calcium carbonate.With the development of technology, most of them use superfine light activated calcium carbonate, or even nanometer calcium carbonate, which not only plays the role of increasing rigidity and filling, but also has the role of modification, but its filling amount is not unlimited, and its proportion should be controlled.Nowadays, some manufacturers add calcium carbonate to 20-50 parts of mass to reduce costs, which greatly reduces the physical and mechanical properties of plastic profiles, resulting in brittle plastic profiles.
Add type and quantity
Impact modifierIt can improvepolyvinyl chlorideOne kind of total rupture energyPolymer。The main varieties of impact modifiers for rigid PVC include CPE, ACR, MBS, ABS, EVA, etc. Among them, the molecular structure of CPE, EVA, ACR modifiers does not contain double bonds, and the weather resistance is good. They are suitable for outdoor building materials. They can be effectively improved by blending with PVCUPVCThe impact resistance, workability, weather resistance and the strength of weld corner can be improved within a certain range.The experiment demonstrates that the impact strength of ACR is about 30% higher than that of CPE.Therefore, PVC/ACR blend system should be used as much as possible in the formula, and when CPE is used for modification and the dosage is less than 8 parts by mass, the plastic profile will be brittle.
Too much or too little stabilizer
The amount of stabilizer varies according to the type of plastic profile, but on the whole, excessive amount will delay the plasticizing time of the material, so that the material will not be plasticized when it is exported to the mold, and the molecules in the formula system are not fully dissolved, resulting in the unstable intermolecular structure.When the dosage is too small, the relatively low molecular substances in the formula system will be degraded or decomposed (also known as superplasticization), and the stability of the intermolecular structure of each component will be damaged.Therefore, the amount of stabilizer will also affect the impact strength of plastic profiles. Too much or too little will reduce the strength of plastic profiles and cause brittle plastic profiles.
Too much
The external lubricant has low solubility with the resin, which can promote the sliding between resin particles, thus reducing the friction heat and delaying the melting process. This effect of the lubricant is greatest in the early stage of the processing process.External lubricants are divided into early lubrication and late lubrication. Materials with excessive lubrication show poor appearance under various conditions. If the amount of lubricant is inappropriate, flow marks, low output, turbidity, poor impact, rough surface, adhesion, poor plasticization, etc. may be caused.Especially when the amount is too much, it will cause poor compactness and plasticization of plastic profiles, resulting in poor impact performance and brittle plastic profiles.
Use and maintenance
Announce
edit
Plastic profile extrusion die is the core part of extrusion production. The technical status of plastic profile extrusion die is directly related to the stability of extrusion production, the quality of extruded products, the extrusion production efficiency and the service life of the die itself.Therefore, the correct use and maintenance of plastic profile extrusion die is very important.
1. Unpacking inspection after arrival of plastic profile extrusion die
Unpacking inspection: take out the packing list, instruction manual and other technical documents after unpacking, and count the whole mold, accessories, special tools, etc. according to the contents of the packing list.
2. Half technical requirements and status of plastic profile extrusion die
The plastic profile extrusion die, especially when the extrusion material is modified PVC, is generally made of stainless steel and other corrosion-resistant materials, and tempered to HRC24 or above to ensure a certain service life.
The working surface of the die, setting die and its parts shall be smooth and free from such defects as bumps, scratches, burrs, attachments and rust.
The flow channel system of the die head should be gentle along the melt flow direction, and try to avoid abrupt changes in the cross section and stagnation zone.
Each formwork shall be positioned reliably, and the repeatability error of loading and unloading of corresponding positions between formworks shall not be greater than 0.03mm;Each joint surface and splicing surface of plastic profile extrusion die head shall be well sealed, and its local clearance shall not be greater than 0.02mm.
The cooling system and vacuum system of the sizing die should be smooth and leak free. Generally, the water and gas systems should not be interconnected.The water pipe joint and vacuum pipe joint of the plastic profile extrusion die shall have obvious marks and shall not affect the connection of the pipeline.
The setting die of plastic profile extrusion die shall be flexible in opening and closing, and the setting die of each section and the block in the water tank shall ensure a certain coaxiality.
Development status
Announce
edit
In recent years, China's plastic profile industry has accelerated the pace of research, development, promotion and application, and its production and sales volume has ranked first in the world.Among them,Plastic pipe、Plastic sheetSuch products have entered a stable and mature growth period, and are the most mature varieties of plastic profiles.
The main products of the plastic profile industry include: plastic doors and windows, plastic pipes, plastic plates, plastic waterproof rolls and plastic profiled materials.Among them,Plastic Profile , plastic pipes, plastic plates and other products have formed a hugeChemical building materialsIn the industrial chain, plastic profiles alone have an annual production capacity of 2.8 million tons, and China has entered the ranks of the largest plastic country.
Today,Plastic building materialsSuch products have developed from interior decoration parts to structural parts and functional parts.Plastic floor. The sales volume of interior wall decorative parts has maintained a steady growthWaterproof material, external wall supportExterior wall insulation board, plastic reinforced bricks, etc. are being used more and more, and their growth rate has exceededPlastic pipe。
It is expected that in the next 5-15 years, under the guidance of various national building energy conservation policies, the market of plastic building materials is expected to develop more rapidly.By 2015, all kinds ofbuilding plasticsThe average market share of pipes and plastic doors and windows will reach 50% and 30% respectively.In terms of demand, various building plastic pipes and plastic doors and windows, together with polymer waterproof materials, decoration materialsThermal insulation materialAnd othersBuilding plasticsThe total demand for products is expected to reach 10 million tons.
The rapid development of the industry and the continuous expansion of production capacity have intensified the competition among plastic profile enterprises.In addition, the domestic market has gradually become saturated, and many profile enterprises have begun to look for development opportunities in the international market.In the future, the competition among plastic profile enterprises will depend more on the mastery of core technologies among enterprises. In addition to constantly improving the comprehensive level of products, enterprises need to adapt to industry standards in different countries and obtain relevant international certification or access permits.
