The main component is polyvinyl chloride, and other ingredients are added to enhance its heat resistance, toughness, ductility, etc. The top layer of this surface film is paint, the main component in the middle is polyvinyl chloride, and the bottom layer is back-coated adhesive. It is a synthetic material that is well-loved, popular and widely used in the world today.

Basic Introduction

Business Card

PVC, the full name is Polyvinylchlorid, and its global usage ranks second among various synthetic materials. According to statistics, in 1995 alone, the production of PVC in Europe was about 5 million tons, and its consumption was 5.3 million tons. In Germany, the production and consumption of PVC averaged 1.4 million tons.

Overview PVC pipe (UPVC pipe) is a rigid polyvinyl chloride pipe, which is made of polyvinyl chloride resin, stabilizer, lubricant, etc. and then extruded by hot pressing. It is the earliest plastic pipe to be developed and applied. UPVC pipes have strong corrosion resistance, are easy to bond, low price, and hard texture. However, due to the leakage of UPVC monomers and additives, they are only suitable for water supply systems with a delivery temperature not exceeding 45¡ãC. Current situation and development of PVC Since the early 1980s, the country has vigorously promoted the application of UPVC pipes, formulated a series of policies, systems, and standards, and accumulated a lot of experience. Today, it has developed to a complete product standard, test method standards and test methods, construction engineering technical specifications, etc., thereby unifying the specifications and quality indicators of the products and realizing the interchangeability of the products. This shows that the development of PVC water supply pipes has entered a mature stage, and both product quality and construction quality are guaranteed, thereby ensuring the use effect of PVC water supply pipes.

PVC size and specifications

Hard PVC pipes have a nominal outer diameter of 50CM, but the largest soft PVC pipe is generally 50mm.

Hard PVC pipe specifications: GB/T13020-1991

Soft PVC pipe specifications: GB/T13527.1-1992

Hard PVC pipes have nominal outer diameters: (unit: mm)

2.5, 3, 4, 5, 6, ..... 355, 400, 450, 500, 560, 630, 710, 800, 900, 1000, etc.

Injection mold process conditions

Drying treatment: Drying treatment is usually not required. Melting temperature: 185~205C Mold temperature: 20~50C

Injection pressure: up to 1500bar Holding pressure: up to 1000bar Injection speed: to avoid material degradation, generally use a corresponding injection speed. Runners and gates: all conventional gates can be used. If processing smaller parts, it is best to use a pinpoint gate or a submerged gate; for thicker parts, it is best to use a fan gate. The minimum diameter of the pinpoint gate or the submerged gate should be 1mm; the thickness of the fan gate cannot be less than 1mm. Typical uses: water supply pipes, household pipes, house wall panels, commercial machine housings, electronic product packaging, medical equipment, food packaging, etc.

PVC development history

PVC profile products have experienced an introduction period and a high-speed development period, which can be defined as the 1980s-mid-1990s and around 1995-2002 respectively. After 2003, the PVC profile industry entered a period of transformation. During the introduction period of the product: manufacturers generally pursued low costs, simplified the cross-section of door and window profiles, and filled a large amount of calcium carbonate in the formula, resulting in low product performance. The emergence of many quality problems affected the promotion of the product.

Since 1995, a group of powerful enterprises have begun to digest and absorb the technical essence of foreign European profiles, developed their own door and window series, and became the leader of China's plastic doors and windows, promoting the technological update and development of doors and windows, and also making the entire industry unprecedentedly developed and growing at a high speed. After entering the mature stage of the product, that is, since 2003, many drawbacks began to emerge. Excessive profit margins led to excessive blind investment, making the industry's comprehensive production capacity nearly 3 million tons, far higher than market demand; many new investors did not start with product innovation and technological innovation, but simply imitated, even cut corners, counterfeited and made inferior products, and the industry market competition was in an unhealthy state. The continuous rise in the price of the raw material market has aggravated this unhealthy competition, causing some companies to be in a difficult situation and stop production or semi-stop production.

Current situation of PVC profile industry

There are many manufacturers in this industry (nearly 400), small output and large production capacity (2.8 million tons), small demand (1.2 million tons of profiles were sold nationwide in 2003), and the contradiction that the production capacity cannot be fully utilized. There are less than 10 companies with an annual output of more than 20,000 tons. The product quality level is uneven, and inferior products still have a market. The industry's quality and technical standards are too low, which is not conducive to technological progress, resulting in the comeback of substitute aluminum. The high-end market (30%) is occupied by foreign brands, and the low-end market is unprofitable and competitive. The final pattern has not yet been formed. From the perspective of factory distribution, among the 392 profile manufacturers, 37% are in the southeast region, 12% in Shandong, 17% in the central region, 19% in the northeast region, and 15% in the western region. From the perspective of the distribution of production capacity, the national production capacity in 2003 was 2.8 million tons, 9% in Shandong, 1% in the central region, 32% in the northeast region, 7% in the western region, and 39% in the southeast region.

Prospects for the development of PVC profiles

During the "Ninth Five-Year Plan", China achieved an average annual economic growth rate of 8%. In the "Tenth Five-Year Plan", it was clearly pointed out that further strengthening infrastructure construction and implementing urbanization strategies would provide broad space for the development of the national building materials industry.

Current situation of the PVC pipe industry

As one of the products of scientific and technological development, PVC pipes are visible in daily life. In Europe, the growth rate of plastic pipes from 1980 to 1990 was 8%, and the output reached 3.5 million tons in 2001, of which PVC pipes accounted for 60%. In 1985, the output of plastic pipes in the United States was 1.6 million tons, and in 1999, the output was about 3.6 million tons, of which PVC pipes accounted for 78%. The first UPVV expanded pipe in China was born in 1983 in Shenyang Plastic Factory (the predecessor of Shenyang Jiuli). Since then, mainland China has the production capacity of PVC water supply and drainage pipes. The late 1990s was a period of rapid development of PVC pipes in mainland China. During this period, some factories with an annual production capacity of more than 50,000 tons were built and put into production, and there were more than 30 PVC pipe factories with a production scale of more than 10,000 tons. At present, the annual production capacity of plastic pipes is 2 million tons.

How to buy

How to buy PVC pipes

1: First look at the surface finish and whiteness.

2: Take the sample and break it. Those that are easy to break are generally high-calcium products. Of course, if they meet your requirements and the price is right, it is okay.

3: Take the sample and step on the edge of the pipe with your feet to see if it can be cracked, or the elongation at break after cracking. (Generally, you have to put the pipeline first to try it, haha, otherwise people will not let you step on it)

4: Weather resistance. The most direct way is to put it in a high temperature and high light place for a few days to see the surface change rate, but it is too time-consuming. Just look at the first 3 items. PVC pipe price

The price of PVC pipes on the market is generally five or six yuan more expensive per meter than ordinary pipes, but the prices of PVC pipes from different manufacturers are different. Big brands such as Jinde, Weixing, and Zhongcai are definitely more expensive, while Wuhan Jinniu, Shifeng, and Baidie are medium-priced. PVC pipes produced by small workshops in Zhejiang are cheap, but the quality cannot be guaranteed.

PVC pipe brand

PVC pipe--Rifeng

Rifeng PVC pipe has a large network coverage, and its influence in the pipe market cannot be underestimated. However, in recent years, due to its low-key behavior, Rifeng PVC pipe has slow market progress and has fallen behind a little. It mainly does engineering, with excellent quality and slightly higher prices.

PVC pipe--Weixing

Weixing PVC pipe has a large brand reputation and basically covers all areas. In 2010, it invested a lot in advertising to rush to go public. It is also a famous Chinese brand. A well-known Chinese trademark. Retail and engineering.

PVC pipes--Jinniu

Jinniu is a relatively down-to-earth enterprise, mainly engaged in engineering, with less retail of PVC pipes, and the quality is not bad. From the establishment of the factory to now, it has developed steadily, without arrogance or impatience.

PVC pipes--Zhejiang Deao

Zhejiang Deao PVC pipes have a good brand image, good quality, and a price much lower than Weixing. It is a new generation of potential stocks in the pipe market. Its main focus is safety. In the reality that home decoration pipes pay more and more attention to safety, Deao PVC pipes¡¯ main safety pipes can indeed win the recognition of many consumers, thus making it quickly jump to the first-line brand.

PVC pipes--Sobong-Pirsa

Sobong-Pirsa PVC pipes are Shanghai brands, with good quality and after-sales service, medium to high-end prices, and a mid-to-high-end brand. It is a designated product for China's North and South Pole expeditions and has reliable quality.

Existing problems

China's PVC pipes have developed rapidly in recent years, with an annual growth rate of 8%, while the annual demand growth rate is 2%. Among plastic pipes, the use of PVC pipes has always been far ahead.

Due to the relatively mature technology, the investment in product innovation of PVC water supply pipes in recent years is not large, and there are relatively few new products. There are many ordinary products on the market, and few high-tech and high-value-added products. Similar general products and medium and low-end products account for the majority, and there are few high-end products. The impact of the lead ban on PVC-U pipes should be faced. The regulation that PVC-U drinking water pipes must use non-lead salt heat stabilizers has a greater negative impact on the PVC pipe industry. Although relevant departments, industry associations and some manufacturers have made a lot of efforts, held a special press conference, and used the media for publicity, the overall situation has gradually become rational, but because some users still do not know the real situation very well, the growth rate of PVC-U drinking water pipes is lower than the average growth level, and there is also a potential negative impact on the application of other PVC-U pipes. The work of expanding the application field and market promotion needs to be improved, and the application and supporting technologies need to be further improved. The work of industry and product publicity, popular science and other aspects is not in place, which affects the reasonable use of plastic pipes and the expansion of the application field. The relevant work of the industry association needs to be improved, and the promotion and publicity efforts need to be strengthened. At present, the application market of products is still concentrated in a limited number of fields, and there is still an opportunity to open up new application markets. The supporting technologies for the application of some products are not yet complete, and the standardization work of the design, construction, acceptance and other work of some products is relatively lagging behind. The market is not standardized, and the product quality of some enterprises is poor, which affects the healthy development of the industry. Because the plastic pipe market is not standardized, some buyers are not the end users of the products, and do not pay attention to the brand and quality, resulting in the coexistence of products of different qualities in the market, and even in some places, products with low quality and low price are better sold, and PVC-U pipes are still more serious. It is understood that there are more than 500 PVC-U production enterprises in a certain county-level area, and most of them are family workshops, and the quality situation can be imagined. The price of raw materials accounts for about 70% of the cost of PVC-U pipes. Some enterprises reduce product costs by reducing wall thickness and adding a large amount of calcium carbonate, resulting in poor product quality. Some enterprises use more than two different quality trademarks, use low-grade processing equipment, and use lead salt stabilizers to produce drinking water pipes to reduce costs, which damages the rights and interests of consumers and undermines the reputation of the industry. The quality of engineering construction should be further improved. The quality of PVC-U pipeline projects depends largely on the construction level. Good products and good construction can ensure the smooth operation of pipeline system projects. In some projects, technical personnel lack professional training. In actual operation, they follow the method of metal pipes for design and construction. There are situations such as non-standard construction and barbaric construction. The technical and economic performance of PVC-U pipelines is not fully utilized, and even pipeline damage is caused. Some users still do not understand the knowledge that should be popularized such as how to construct and supervise plastic pipelines according to regulations. PVC resin, additives, etc. restrict the development of the industry. In recent years, plastic pipelines have driven the development of related industries, but some PVC resin manufacturers in the upstream industry still have unstable PVC resin quality. Some PVC resin particles have poor regularity, some resins have high residual VCM content, and there are few special materials for pipelines. Some processing aids cannot be domestically produced at present, and some quality is not very stable. Some technical performance does not meet the requirements, which restricts the further improvement of the performance of pipeline products.

The difference between the two

The difference between PVC-U and UPVC

PVC-U and UPVC are what we usually call PVC pipes, but the order of writing is different.

During the PVC production process, in order to increase the plasticizing properties of PVC and improve production efficiency, plasticizers (such as DOP, DBP, DINP, etc.) will be added, and PVC products with added plasticizers will be softer.

Generally, we refer to PVC products that do not add plasticizers during processing as UPVC, which can also be written as PVC-U.

Construction and maintenance

There are three main ways to connect PVC pipes: sealing rubber ring, bonding and flange connection. Pipes with a diameter greater than or equal to 100 mm generally use rubber ring interfaces; pipes with a diameter less than 100 mm generally use bonding joints, and some use live joints. When the pipeline crosses the sewer or other pipelines, metal pipes are generally used. At this time, the plastic pipe and the metal pipe are connected by flanges. The connection between the valve and the pipeline before and after is also flanged.

1 When solvent bonding is used for small-diameter pipes, the sockets must be chamfered to form a bevel, and the fracture must be flat and perpendicular to the axis, so that the bonding can be firm and water leakage can be avoided.

2 Generally, PVC pipes with a diameter greater than or equal to 100 mm use rubber ring interfaces. Before installation, personnel must be arranged to chamfer the pipe sockets and check whether the quality of the rubber rings is qualified. The sockets, rubber rings, etc. must be wiped clean during installation.

3 The trench excavation for traditional pipeline installation only requires that the pipes can be placed in the trench and sealed. When the original soil layer is not loosened, there is no need to pressurize and compact the cushion layer.

4 Generally, PVC pipe branches can be split with tees or vertical water stop plugs. During construction, a saddle-shaped accessory and half a two-in-one tee can be added and clamped with U-shaped bolts, which thickens the pipe wall, and then holes are drilled directly on it, and then connected with external threaded plastic parts. The test shows that the pressure test acceptance after construction using this method can fully meet the requirements of the specification. In addition, thrust piers should be set at the locations where the water flow in the pipe generates thrust, such as elbows, tees and pipe end sealing plates, to withstand the thrust of the water flow.

5 PVC pipes are a new type of non-metallic pipes. The existing metal pipe detection equipment cannot detect their specific locations. However, if an electric wire is buried on the pipe during the pipeline burial construction, this problem can be easily solved.

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