Stone plactic composite (SPC) is a new type of environmentally friendly floor developed based on high-tech, with zero formaldehyde, mildew proof, moisture proof, fire, insect proof, easy installation and so on.SPC floor is by extruder combined with T-mold extrusion PVC substrate, with three or four or five roller calender respectively PVC wear-resistant layer, PVC color film and PVC substrate, one-time heating and laminating, embossing products, simple process, laminating by heat to complete, do not need glue.SPC floor materials use environmentally friendly formula, does not contain heavy metals, phthalates, methanol and other harmful substances, in line with EN14372, EN649-2011, IEC62321, GB4085-83 standards. It is widely popular in developed countries in Europe and the United States and the Asia-Pacific market. Stone plactic composite (SPC) is a new type of environmentally friendly floor developed based on high-tech, with zero formaldehyde, mildew proof, moisture proof, fire, insect proof, easy installation and so on.SPC floor is by extruder combined with T-mold extrusion PVC substrate, with three or four or five roller calender respectively PVC wear-resistant layer, PVC color film and PVC substrate, one-time heating and laminating, embossing products, simple process, laminating by heat to complete, do not need glue.SPC floor materials use environmentally friendly formula, does not contain heavy metals, phthalates, methanol and other harmful substances, in line with EN14372, EN649-2011, IEC62321, GB4085-83 standards. It is widely popular in developed countries in Europe and the United States and the Asia-Pacific market.

SPC地板的主要质量要求

SPC Main performance requirements of the floor

1. It has low shrinkage, warpage and good toughness.
2, to ensure that it is not easy to deform and better locking tension in various environments and a certain peeling force between the substrate and the film. The performance mainly depends on the material type component processing equipment capacity to determine.

Processing requirement

1, because the SPC floor production line extrusion volume is relatively large, and the need for online coating, so the stability of continuous production is very important.
2, because the SPC floor is high fill, screw wear is serious, screw value is high, so we must consider the impact of screw life on the total cost.
3, the floor is relatively thin, the thickness tolerance requirements are small, the extrusion speed is fast, so it requires better material dispersion, plasticizing performance and fluidity.

Processing equipment

1. High wear resistance, relatively low extrusion pressure and good plasticizing screw barrel;
2, design a reasonable and uniform discharge mold;
3. Multi-roll calender system with simple operation adjustment and precise thickness control;
4, the film guided expansion force control correction system is accurate and reliable;
5, and have enough cooling space and capacity;
6, cutting and moving can not have an adverse effect on the appearance of the plate and the degree of warping;
7, manufacturer selection: can not one-sided pursuit of output, but according to the thickness of their own plate to choose the size of the machine. 80/92/110 ADAPTS to the production of plates with different thickness ranges, and the general configuration of 1:2:1 or 1:3:1 is more reasonable.
(The size of the extruder and the thickness of the plate should be reasonably matched)

Recipe essentials
1, PVC resin: the use of ethylene method five type resin, strength toughness is better, environmental protection.
2, the fineness of calcium powder: because the addition proportion is large, it directly affects the formula cost, processing performance and wear and product performance of the screw barrel, so you can not choose too coarse calcium powder, calcium powder fineness to 400-800 mesh is appropriate.
3, internal and external lubrication: considering the high temperature residence time of the material in the extruder, as well as the performance of the material and the stripping force, it is recommended to use high-performance wax to control the smaller amount of use, and the use of different wax to meet the initial and medium - and long-term lubrication requirements.
4, ACR: Due to the high content of calcium powder on the SPC floor, high plasticization requirements, in addition to the control of screw type and processing technology, it is necessary to help plasticization by adding additives, and ensure that the melt has a certain strength, and has a certain ductility in the calendering process.
5, toughening agent: the floor not only needs low shrinkage rate, good rigidity, but also needs a certain toughness, rigidity and toughness need to balance each other, to ensure the firmness of the lock, not soft at high temperatures, and maintain a certain toughness at low temperatures. The toughness of CPE is good, but the addition of a large number of components reduces the rigidity of PVC, the softening temperature of Vica, and the shrinkage rate becomes larger.
6, dispersant: Because there are more components, and the proportion of calcium carbonate is relatively large, so the invasion and dispersion of calcium carbonate and the dispersion of each component are very important. The dispersion can not only improve the processing performance but also improve the performance of the product, improve the stripping cycle, reduce and delay the wear of the screw barrel.
PE wax is not only a lubricant, but also has a dispersion effect, but the amount of addition will affect the balance of internal and external lubrication and the deterioration of melt strength, and increase the shrinkage rate of the product and reduce the stripping force, and the product becomes brittle. Other dispersants: fluorinated compounds, isocyanate compounds, the amount is small, the effect is good, not only play a dispersive role and coupling lubrication, but the price is high.
7, return material: try to use the company's production and post-processing of recycled materials.
Note: Clean, not wet, batch crushing and blending after grinding. In particular, the recovered material of the segmented groove must be proportionally blended with the grinding powder to form a closed return cycle. It is necessary to adjust the process formula of the sample when the amount of return material is changed greatly.

Processing technology and control

1. Formula and weighing
Different kinds of weight materials, need to use the corresponding precision of the weighing instrument to ensure the accuracy of the weighing.
Material integration: convenient storage, weighing, flow and feeding, the need for sample review of components and accuracy. If it is an automatic weighing system, it should also be monitored and reviewed.

2, mixed storage

Order of feeding: Determine the order of feeding according to the way of feeding.
The automatic feeding mixing system can be set to: filler 90℃, treatment agent and PVC resin 95℃, stabilizer lubricant 105-110℃, processing aid reinforcement agent 115℃, and return material 120-125℃.
Artificial feeding: PVC resin + filler + small material +PVC resin + filler +PVC resin + return material; One-time feeding, 120-125℃ discharge.
Cold mix: must be fully and quickly cooled to prevent material deterioration, and has the ability to cool to 40-45 ° C.
Storage: In order to ensure the uniformity of the material, it is necessary to use a large storage tank for storage and shelving for a certain time before use.
Mixing materials that have been shelving for a certain period of time requires testing the dry flow properties of different batches of materials, and testing the rheological properties of logistics as a means of monitoring and providing a basis for analysis and improvement.

Note that there are differences in mixing effect, mixing temperature and time between different mixers.

3, extrusion process
The setting of processing technology not only affects the processing level, but also affects product quality and production efficiency. It is necessary to consider the equipment characteristics, material properties and formula together.
The relationship between the size of the extruder and the specifications of the product, and the size of the extruder has a certain relationship with the cross-section size of the product.
First of all, at a certain extrusion speed of the fb extruder, the production line speed is fast, the molding pressure is relatively high, and the requirements for plasticization and fluidity of the material are high. If the production depends on the open die gap, the longitudinal tensile is relatively large, and the melt strength is high, and the tensile orientation is easy to cause a large difference in the vertical and horizontal shrinkage rate, resulting in excessive shrinkage rate and sheet warping. At the same time, high speed production has high requirements for calendering and laminating cooling.
If the floor is produced using a 110/135 extrusion line, the formulation process should be carefully designed and set up.
According to the current situation: the die clearance is slightly greater than the floor thickness.

Fuselage: The temperature of Zone 1 and Zone 2 is very important, and it is necessary to ensure that plasticization is easy to vacuum. Too high, easy to accumulate material in the vacuum mouth, generally between 185-195 ° C, others can be slightly lower.
The temperature of the confluence core has a great influence on the back pressure, and the lower point is favorable for the melt to change from spiral motion to linear movement, generally at 165-175℃.
The mold temperature is relatively higher, which is conducive to the flow of small gap melt. Generally between 190-200℃, combined with the mold gap corresponding to adjust the thickness of the blank uniform.

Extruder main engine speed: generally controlled at the rated speed of 75-85%. The feeding speed is mainly determined by the main engine speed and the main engine (load) current.
Under the premise of determining the formula, the processing temperature, the main engine speed and the feeding speed match each other, so that the current is stable, the discharge is uniform and the surface is without defects, and there is a certain production speed.
Wear occurs when the screw is used for a certain time. First, the processing technology can be adjusted, such as reducing the extrusion speed, increasing the feeding speed, and appropriately increasing the processing temperature in the first and second zones to reduce the temperature of the confluence core. Adjust the formula appropriately to increase the amount of ACR. If necessary, re-adjust the clearance related to the screw barrel, polish and polish the damaged part, and then adjust the process formula. 4, rolling film process

Under the premise of stable extrusion.
Main control: roller clearance, temperature, speed, and the matching of front and rear speeds.
The clearance and speed of the first pair of rollers determine the basic thickness of the floor, which should be initially determined according to the linear speed of the extrusion. The speed of the back coated roller is slightly faster to ensure that there is a certain expansion force, and it is appropriate not to cause the film tensile narrowing. The traction speed is so that the plate does not deform. Some adjust slowly according to the actual situation. Embossing and film coating, mainly rely on roller gap, roller temperature, different plate thickness, film type, using different gap and temperature, and consider the influence of traction speed.
Roller temperature speed: should ensure normal rolling, clear embossing, film bonding, cutting edge is sufficient, film does not deformation.

Roller temperature: generally 165-185℃.
The gap between the two pairs of rollers is basically the same. The two need to be adjusted in combination.
80 unit 4mm floor reference Production process reference:

Heat mixing: 125℃

Cold mixing: ≤45℃

Die gap: 3.8 ~ 4.0 slightly smaller in the middle

Body:

Host speed: 20rpm

Main machine current; 75A
Feeding speed: 10rpm
Rolling clearance: 4mm
Roller temperature: 175℃
Roller and traction speed: 600 (table value)

5. Styling and others
Because the product in the production process has not been completely shaped, the cutting flow avoids stress, and the bearing tray needs to be strong and smooth. Product testing also requires the substrate and finished product to be placed for a certain time for sampling.

6, common problems analysis - poor product molding

A brief analysis of common problems

conclusion