In outdoor engineering materials, HDPE high density polyethylene sheet has gradually replaced traditional wood, steel, PVC plate, and become the mainstream sheet material for outdoor use. The core issues that many procurement personnel and engineering leaders are most concerned about are always concentrated on three points: How long is the real outdoor service life of HDPE sheets? Why do some of the same plates take a few years, and some use more than ten years? How to extend outdoor use cycle from root cause? This article will focus on depth analysis of HDPE sheet outdoor service life, core factors, selection of outdoor HDPE sheet program.
What is high density polyethylene sheet?
HDPE sheet, referred to as HDPE sheet, is the most widely used environmentally friendly thermoplastic engineering plastic sheet in industrial engineering, municipal gardening, aquaculture and outdoor construction. It is made of high density polyethylene resin particles as the core raw material, after high temperature melting, homogeneous extrusion, pressure molding, constant temperature cooling, precision cutting and other automatic processing, is a solid plastic plate with dense structure, stable performance and strong comprehensive practicability. Different from ordinary low-density soft plastic, PVC hard board, acrylic sheet. Its biggest material characteristics are rigid and ductile balance, not only enough hardness is not easy to deform, but also has excellent toughness is not easy to brittle crack, will not be like ordinary plastic cold cracking, hot soft, also will not be like metal materials heavy, easy to rust, more will not be like wood plate easy to rot moldy, is suitable for outdoor complex conditions of high-quality engineering materials.
The advantages of HDPE sheet are very prominent. The board has extremely low water absorption, almost zero water absorption, excellent waterproof and moisture-proof performance; stable chemical properties, and can withstand corrosion of weak acid, weak base, salt water, rain water, and wet salt spray at normal temperature; excellent wear resistance, impact resistance, and compression resistance, and can withstand long-term equipment rolling, heavy impact, and repeated friction; wide temperature range, and can maintain structural stability under high and low temperature environments, and is not easy to deform and crack.
Outdoor special plates will add anti-ultraviolet stabilizers and antioxidants to improve weather resistance and anti-aging ability; special plates for coastal and chemical scenes will increase salt spray resistance and acid and alkali resistance additives to further improve corrosion resistance. At the same time, the plate supports full size customization, thickness, length, width and color can be processed on demand to meet the pavement requirements of different projects.
Why HDPE sheets are used outdoors？
Outdoor environment is subject to sun, rain, temperature change, salt fog corrosion and mechanical wear all the year round, which requires extremely high weather resistance and stability of building materials.Traditional wood perishes easily, steel plate rusts easily, ordinary plastic embrittles easily and ages easily, and it is difficult to use it stably in the open air for a long time.In contrast, HDPE sheet has excellent comprehensive properties and is very suitable for various outdoor scenes.
HDPE sheet water absorption rate is very low, waterproof and moisture-proof performance outstanding, long-term rain soaking will not expand, moldy, rotten, completely solve the disadvantages of wood sheet outdoor afraid of water.At the same time, the material has stable chemical properties, acid and alkali resistance, salt spray corrosion resistance, and will not rust and corrode like steel in complex outdoor environments such as coastal areas, factories, gardens, etc., without frequent anti-corrosion maintenance.
In terms of weather resistance, HDPE sheet has balanced high and low temperature resistance, high temperature exposure does not deform, low temperature environment does not crack, and can adapt to temperature difference climate all over the country.After modification with anti-UV additives, it can effectively resist UV damage, greatly delay fading, powdering and aging problems, and meet the needs of long-term outdoor use.
In addition, HDPE sheet has strong toughness, wear resistance and impact resistance, can withstand outdoor personnel stepping, equipment rolling and friction loss, and is not easy to damage and deform.And the material is environmentally friendly, non-toxic, light weight, convenient installation and cutting, low construction cost, comprehensive adaptation to all outdoor engineering use scenarios.
Universal life of HDPE sheets
The outdoor service life of HDPE sheet has no fixed uniform value, and its service life mainly depends on multiple factors such as raw material quality, production formula, whether to add anti-UV additives, use environment and bearing load.HDPE sheets of different material grades have great differences in aging speed and service cycle in outdoor environment.Combined with long-term outdoor measured data in different regions of the country, the service life of HDPE sheet can be divided into three clear grades, which is also the most authentic and authoritative reference standard for engineering material selection at present.
HDPE sheet recycling
This kind of plate has low cost, recycled from waste plastics, with many internal impurities, incomplete molecular chains, unstable structure, no anti-aging and anti-UV additives added in the production process, and poor overall weather resistance. It is only suitable for indoor temporary bedding, and is completely unsuitable for long-term outdoor conditions.In the year-round non-sheltered exposure environment, the service life of recycled materials is only 1 to 2 years. After one year of use, large-area fading, whitening, powdering, slag dropping and other aging phenomena will occur, and the toughness of the plate will be greatly reduced. Minor impact and rolling will crack and damage.Even if placed in eaves, shade and other semi-sheltered outdoor environment, the limit service life is only 3 to 5 years, and it is easy to brittle deformation in the later stage and lose its use value.
New material Ordinary HDPE sheet
This kind of plate is made of 100% new original polyethylene particles, pure material, stable structure, good wear resistance, waterproof, impact resistance, but no anti-ultraviolet additives added, sunscreen aging resistance is limited.In a completely open environment, the new material ordinary plate can be used stably for 5 to 8 years, the early use of good condition, the later will slowly fade, slightly powdered, but the overall structure will not be damaged.If it is used in semi-outdoor scenes such as building shadows and green plants, the ultraviolet radiation is reduced, the aging speed is greatly reduced, the service life can reach 8 to 12 years, and the cost performance is very outstanding.
Outdoor special material UV resistant HDPE sheet
This kind of plate adds high content of ultraviolet absorber and antioxidant on the basis of new raw materials, and the weather resistance is greatly improved.In the inland mild urban conventional open air environment, the service life can reach 10 to 20 years; in high temperature exposure, coastal salt fog, plateau strong ultraviolet and other harsh conditions, it can still be used stably for 10 to 15 years.High-end thickened marine UV resistant sheet, the longest service life of up to 25 to 30 years, can meet the needs of permanent outdoor engineering.
Factors affecting the service life of HDPE sheet
Many customers purchase the same HDPE sheet, used in different outdoor sites, there is a huge gap in service life, the core is the outdoor environment, the sheet itself, the construction of the three dimensions of the existence of differentiated variables, five core factors directly determine the aging speed of the sheet and the actual service life, each factor will have a key impact on the life of the sheet.
UV light intensity
The medium and short wave ultraviolet rays in the sun are the main culprit that destroys the molecular structure of HDPE. The molecular chain of polyethylene will be oxidized and broken under the continuous irradiation of ultraviolet rays, which will directly cause the fading of the board, the powdering of the surface layer, the decrease of toughness and the brittle cracking, which is the root cause of all outdoor board aging.
The higher the light intensity, the faster the aging speed: the tropical cities in South China have long sunshine hours and high ultraviolet intensity throughout the year, and the aging speed of the board is 1.8 times that of the mild inland cities in the north; the air in the plateau and northwest Gobi regions is thin, the ultraviolet penetration is stronger, and the aging speed is doubled; the reflection of ultraviolet rays on the sea surface in the coastal areas will be reflected twice, and double irradiation accelerates the loss of the board.
Whether the plate is added with anti-UV additives is the key dividing line to resist ultraviolet rays: the plate without UV additives cannot neutralize ultraviolet rays, and the molecular chain continues to be damaged and aged; the outdoor special plate with sufficient UV stabilizers can absorb more than 90% of harmful ultraviolet rays, greatly delay the oxidation aging process, and directly increase the service life by more than 3 times.At the same time, the color of the plate will also affect the sun resistance, dark color (black, dark green, dark blue) itself has natural ultraviolet absorption capacity, the same amount of additives added, dark plate outdoor weather life is better than white, light yellow and other light plates, white plate outdoor exposure yellow, fading speed is the fastest.
Raw material purity and formulation process
The purity of raw materials directly determines the upper limit of the basic weather resistance of the plate. There are a lot of impurities and broken molecular chains in the recycled miscellaneous material plate. There are structural defects in the factory itself. The defects will expand rapidly in the outdoor environment, and the service life will be greatly reduced. 100% of the new virgin material plate molecules are complete and uniform, and the basic weather resistance is full. The same outdoor environment life is 2~3 times that of the recycled material plate.
In addition to raw materials, the amount of functional additives added during production is the second key variable: ordinary plates with only color master added only solve the problem of appearance coloring without any anti-aging ability; outdoor special plates will accurately match ultraviolet absorbers, antioxidants and anti-hydrolysis additives. The higher the additive ratio, the stronger the outdoor weather resistance; Some low-cost manufacturers will reduce the amount of anti-UV additives, in order to reduce the production cost, the plate nominal “outdoor weather resistance”, the actual open-air 3 years on the occurrence of serious aging, procurement needs to focus on screening formula technology.
At the same time, the extrusion molding process will also affect the life: constant temperature uniform extrusion, fully melted homogeneous plate, uniform internal density without bubbles, no stress stratification; inferior high-speed extrusion plate internal pores, delamination, outdoor temperature difference alternating internal stress release, rapid warping, cracking damage.
climatic environment difference
The outdoor climate environment varies greatly in different regions of the country. Temperature, humidity, salt fog and rainwater pH will continue to lose plates, which are divided into four typical climate scenarios
High temperature and rainy areas in the south: long-term high temperature exposure in summer, abundant rainfall throughout the year, high probability of acid rain, high temperature will accelerate the ultraviolet oxidation reaction, rain continues to wash away surface additives, plate aging speed accelerated;
Northern low temperature difference area
the temperature difference of the four seasons exceeds 40℃, the freezing and thawing cycle of ice and snow in winter, the repeated pulling of the plate by day and night thermal expansion and contraction, and the surface cracking of the plate without anti-low temperature additives;
Coastal salt fog area
sea wind carries high concentration of chloride ion salt fog, adhering to the surface of the plate for continuous penetration corrosion, accelerating the surface oxidation, and putting forward higher requirements for the dual performance of weather resistance and corrosion resistance of the plate.
Inland dry plateau area
dry air without rain buffer, ultraviolet intensity is extremely high, surface moisture loss rapidly, plate easy to dry powder.
The same batch of anti-UV HDPE sheets, placed in coastal docks and inland shade sites, the actual service life difference can be more than doubled, and the selection needs to be customized according to the climate of the project location.
Sheet thickness and daily load
The thickness of the plate determines the physical allowance of wear resistance and deformation resistance. In outdoor long-term heavy-duty scenes, the wear rate of the thin plate surface is faster. Under the same working conditions, the wear life of 30mm thick plate is twice that of 10mm thin plate.Thin plate internal structure allowance is small, long-term heavy pressure, friction surface rapid wear, internal substrate exposure, accelerated aging; thick plate has sufficient substrate buffer layer, internal complete substrate can still be used stably after surface wear.
Daily use load will also greatly affect the service life: long-term traffic heavy excavators, concrete mixers, fully loaded forklift heavy load sites, the plate continues to withstand high pressure, drag friction, surface wear rate greatly increased; only light equipment for personnel to pass garden trails, load is extremely low, plate wear is slow, service life is significantly extended.Sharp metal corners and gravel repeatedly drag the surface of the plate for a long time, which will scratch the surface anti-UV protective layer. After the protective layer is damaged, the internal substrate is directly exposed to ultraviolet rays and rainwater environment, and the aging speed is doubled.
Installation and routine maintenance
Non-standard installation will directly shorten the service life of the plate, HDPE plate with thermal expansion and contraction physical characteristics, high temperature environment plate will slightly expand, low temperature environment contraction, if the laying of the plate completely close fit, no standard expansion gap reserved, high temperature expansion in summer after the plate extrusion, arch, warp, corner cracking damage; fixed bolts completely locked without movement allowance, will also limit the plate expansion, internal stress cracking, greatly shorten the service life.
Daily maintenance also affects the life: long-term adhesion of cement slurry, chemical oil, saline-alkali sediment on the surface of the plate, rainwater can not be washed clean, the sediment will continue to corrode the surface anti-UV protective layer, regular clean water simple rinse to remove stains, can completely retain the surface protective layer, delay aging; long-term do not clean stains of the plate, the protective layer damaged in advance, aging speed accelerated by more than 30%.At the same time, long-term accumulation of accumulated water in outdoor sites soaked in the corners of the board, continuous soaking and oxidation of the corners, will gradually expand the damage range from local, do a good job of site drainage, avoid long-term ponding immersion, but also effectively extend the service life of the board.
How to prolong the service life of HDPE sheet
HDPE sheet itself has excellent characteristics such as wear resistance, corrosion resistance, impact resistance, etc, but the outdoor environment has strong ultraviolet rays, large temperature difference, and many corrosion factors. If the material is improperly selected, the installation is not standardized, and the daily maintenance is lacking, the sheet will still have fading, powdering, deformation, cracking and other aging problems, shortening the overall service life.In order to maximize the outdoor service life of HDPE sheets, scientific management is needed from scientific material selection, standardized installation, and regular simple maintenance.
Scientific material selection
In long-term outdoor scenes, it is necessary to give priority to the use of new raw materials with UV resistance and weather resistance, and avoid the use of recycled materials with many impurities and poor performance.New material sheet molecular structure stability, with anti-ultraviolet, antioxidant additives, can greatly resist outdoor sun aging.In the south high temperature, plateau strong light, coastal salt fog and other harsh areas, it is recommended to give priority to the selection of dark plate, dark itself absorbs light, fading slower, weather resistance is better than light-colored plate.At the same time, according to the bearing conditions of the site, the thickness of the plate is reasonably selected, and the thickened plate is selected for the heavy-duty site to improve the wear and compression allowance and delay the aging of the surface wear.
standardized mounting
HDPE sheets have thermal expansion and contraction characteristics, and reasonable expansion gaps must be reserved between sheets during laying to prevent high temperature expansion in summer from squeezing each other, causing arching, curling and cracking.Fixed bolts should not be locked too tight, keep a small amount of expansion space, avoid internal stress caused by temperature change caused by plate damage.Before laying, it is necessary to level the ground, clean sharp stones and sundries, drain the site well, prevent the bottom of the plate from being pressed by hard objects, soak the corners for a long time, and reduce structural damage from the construction level.
Standardized use and simple maintenance
During outdoor use, minimize sharp metals, gravel, and heavy equipment dragging friction plates in place to avoid damaging the surface anti-UV protective layer.Regularly wash the surface of the plate with clean water, remove salt mist, oil, dust, acid and alkali deposits, keep the plate clean, and prevent impurities from adhering to the corrosion plate for a long time.In case of local slight scratches and damages, repair them in time to prevent ultraviolet rays and rainwater from penetrating from the damaged position and avoid the continuous expansion of aging range.
HDPE sheet and other materials comparison
In the process of outdoor engineering material selection, wood, PVC sheet, aluminum alloy, carbon steel are more common traditional materials, but limited by their own material characteristics, there are generally short life, maintenance cumbersome, poor weather resistance and other problems.HDPE sheet, with its balanced comprehensive performance, has gradually become the mainstream alternative material for outdoor construction, landscape, plant protection and coastal engineering.By comparing with various traditional outdoor building materials, the comprehensive advantages of HDPE sheet in outdoor use can be more intuitively seen.
solid wood board
Solid wood panels are the most commonly used outdoor materials in the early days. The advantage lies in their natural appearance and cheap cost, but their outdoor practicality is extremely poor.Wood water absorption is strong, long-term rain easy moldy rot, moth-eaten deformation, after ultraviolet exposure will appear cracking, warping, fading and other problems.In order to maintain use, anti-corrosive paint and insect-repellent agents need to be applied every year. The maintenance cost is high, and the overall outdoor service life is only 2 to 5 years. The replacement frequency is high, and the comprehensive cost performance is extremely low.
PVC plastic sheet
PVC plastic sheet low cost, good waterproof, but weather resistance is seriously insufficient.It is easy to embrittle, peel, crack, age and fall off after long-term exposure in the open air. The toughness becomes poor under low temperature environment, and it is easy to break under crushing and impact.The overall outdoor service life is only 3 to 6 years, and the wear resistance is poor, so it cannot be used for heavy-duty outdoor venues, and is only suitable for simple temporary enclosure use.
Aluminum alloy sheet lightweight, not easy to rust, good appearance texture, service life of 8 to 15 years.However, aluminum alloy is expensive, wear resistance is general, heavy load scene is easy to sag deformation, oxidation whitening occurs in coastal salt fog environment, anti-oxidation treatment needs to be done regularly, maintenance is difficult, not suitable for large-area, high-load outdoor engineering use.
carbon steel plates
Carbon steel plate has high hardness and strong load-bearing capacity, which is a common material for heavy-duty sites, but outdoor defects are very obvious.Steel is easy to rust when it meets water. It needs rust removal and painting after half a year of open-air use. The maintenance process is complicated and the cost is high. The long-term corrosion will cause problems such as thinning, perforation and fracture. The overall outdoor service life is only 3 to 8 years. The comprehensive investment in the later period is much higher than that of plastic plate.
Compared with the above materials, UV resistant HDPE sheet has the most comprehensive advantages.Waterproof corrosion resistance, rust resistance, corrosion resistance, UV resistance, high and low temperature resistance, wear resistance, impact resistance, conventional outdoor service life of up to 10 to 20 years, harsh environment can also be stable use for more than ten years.At the same time, no paint, no corrosion, almost zero maintenance, light construction, moderate cost, can be recycled.Whether it is short-term engineering, medium-and long-term pavement or permanent outdoor projects, the comprehensive performance and cost performance of HDPE sheets are far superior to traditional outdoor building materials.
What are the applications of HDPE sheets outdoors?
With the continuous improvement of weather resistance, wear resistance and corrosion resistance in outdoor engineering, the application range of HDPE sheet is becoming wider and wider, covering almost all outdoor construction and outdoor protection fields.In engineering construction scenarios, HDPE sheets are often used as temporary paving pads, which can disperse heavy mechanical pressure and protect the original pavement from crushing damage.
In the field of municipal gardens, the plates are mostly used in park trails, landscape platforms, tree pool baffles, outdoor boardwalks and other scenes, which are anti-skid and wear-resistant, not easy to fade, do not need frequent maintenance, and are beautiful and durable as a whole.In aquaculture and water environment engineering, HDPE sheet is waterproof and impervious to seawater corrosion. It is often used to make culture pond bottom plate, beach protection plate and pool impervious plate. It will not deform and rot in long-term soaking.
In the outdoor scene of the factory, it can be used as a forklift passage pad, equipment bearing plate, and outdoor cargo bedding. It is resistant to rolling, oil, acid and alkali corrosion.Coastal docks and port areas rely on excellent salt fog resistance to effectively resist sea wind erosion, and their service life far exceeds that of wood and steel plates.In addition, it is also widely used in outdoor enclosures, water conservancy projects, camping bases, scenic spots and other outdoor scenes.
How to choose HDPE sheet correctly
Outdoor use of HDPE sheet, the purchase method directly determines the later service life.First of all, it is necessary to distinguish the grade of raw materials. The brand-new raw material plate has good toughness and strong weather resistance, which is suitable for long-term outdoor use; the recycled material has many impurities and is easy to age. It is only suitable for indoor temporary use. It is strictly prohibited to use it for outdoor long-term projects.
Secondly, according to the use of environmental selection formula, year-round exposure, high temperature, coastal areas must choose with anti-UV, anti-salt spray formula outdoor special plate, delay fading and powdering aging; low temperature areas priority to choose toughened plate, prevent brittle crack.
At the same time, the thickness is matched according to the load-bearing conditions. Conventional thin plates are used for pedestrians and light vehicles, and thickened plates must be used for forklifts, excavators, and heavy trucks to improve wear and compression resistance.When purchasing, try to choose dark plates for open-air scenes, and the sun-resistant effect is better.Finally, observe the texture of the plate surface, the surface of the high-quality plate is flat, no particle impurities, no bubble delamination, uniform toughness, which can effectively avoid problems such as cracking, deformation and aging in advance.
Common problem frequently asked
Q: The thicker the plate, the longer the life?
Thickness only improves wear resistance, UV resistant raw material formula is the key to determine outdoor life.
Q: Can outdoor HDPE board fade and still be used?
Only slight fading does not affect the load-bearing and anti-corrosion performance, no powder cracking can be used normally.
Q: Will the cold plate be brittle in winter?
The new UV plate is not easy to crack at low temperature, and the recycled inferior material is easy to embrittle in winter.
Q: Why do light-colored sheets age faster?
Light color UV absorption weak, the same additives, exposure fading, powdering speed higher than dark plate.
conclusion
HDPE sheet weather resistance, wear resistance, corrosion resistance and durability, suitable for all kinds of outdoor scenes, comprehensive advantages far more than traditional building materials.Xinxing plastics support specifications, formula customization, provide professional selection solutions, procurement needs, please feel free to contact us for quotation.
