Polyurethane spraying construction technology

Polyurethane is widely used in external wall insulation, roof insulation, cold storage, grain depot, archives, pipes, doors and windows and other special parts because of its good thermal insulation and excellent waterproof performance. Today, we will learn about polyurethane spraying construction technology and polyurethane spraying construction technology together, hoping to help everyone.

Polyurethane spraying construction technology

First, the construction points

1, construction preparation

The wall at the grass-roots level shall meet the requirements of the Code for Acceptance of Construction Quality of Concrete Structure Engineering (GB50204-2002) and the Code for Acceptance of Construction Quality of Masonry Engineering (GB50203-2002) and the corresponding code for acceptance of the wall at the grass-roots level and pass the acceptance. The performance index of polyurethane should meet the requirements of JC/T998-2006 "Spray Polyurethane Rigid Foam Insulation Material". The wall should be clean, free of oil stains and floating ash. Construction holes, scaffolding holes, balcony slabs and wall defects shall be repaired neatly with mortar; Loose and weathered parts of the wall should be removed. The flatness error of the foundation wall shall not exceed 3mm.

2, the system structure flow chart

3. Environmental requirements:

A. Meteorology during construction operation shall meet the following conditions: the ambient temperature during on-site spraying operation shall be 15℃-40℃, but it shall not be lower than 10℃ or higher than 40℃; The moisture content of the wall should be 9%, the wind force should not be greater than 5m/s (level 3 wind), and the relative humidity should be less than 80%. Construction is not allowed in rainy days. When the ambient temperature is lower than 10℃ during construction, reliable technical measures should be taken to ensure the spraying quality. It is forbidden to work in high humidity or exposure.

B, external wall thermal insulation construction and operation technical conditions are as follows:

Single-row or double-row steel pipe scaffold along the outer edge, steel pipe portal scaffold; The distance from the decorative surface of the wall shall be (00-2.5m), and the maximum point shall not exceed 5m; It shall be equipped with a fence railing not exceeding1.2m; Its construction must conform to the current national safety technical regulations. Scaffolding should meet the requirements of spraying progress.

C, polyurethane white and black materials should be sealed and stored in a dry, ventilated and cool place. The storage temperature of white materials should be 15℃ ~ 20℃, and should not exceed 30℃, and should not be exposed to sunlight. The storage temperature of black materials should be 15℃ ~ 35℃, which should not exceed 35℃, and the minimum storage temperature should not be lower than 5℃. The storage period of polyurethane white material and polyurethane black material is 6 months. Polyurethane white materials and black materials should have sun protection measures during storage and transportation.

Second, grassroots treatment.

The wall surface should be cleaned up, and the oil stain and floating ash should be removed. Loose and weathered parts of the wall should be removed. The flatness of the wall should be controlled below 3 mm, and the deviation at the grass-roots level is too large, so it should be leveled with mortar. Remove all defects such as external wall attachments, oil stains, concrete beam bulging, etc., and the repair is qualified, and the protruding height is _6_. The gap between masonry and beam-column is treated with steel mesh, and the steel mesh is widened by _200_ on both sides of the joint. Doors and windows have been installed and partially filled.

Three, hanging vertical, elastic control line

Under the top wall and bottom wall, use expansion bolts as hanging points for hanging wires on the big wall. High-rise buildings use theodolite to hang wires, and multi-storey buildings use large wires to hang thin wires. The tightening device is used to tighten the steel vertical line at the large yin and yang angle of the wall. The distance between the steel vertical line and the wall is the total thickness of the insulation layer. After hanging up the line, first check the flatness of the wall with a 2m ruler, and then check the verticality of the wall with a 2m line supporting plate. Only when the flatness requirements are met can the construction begin.

Fourth, the construction process

1, doors and windows blocked, etc.

After the bonding of polyurethane prefabricated parts is completed, shielding work should be fully done before spraying rigid foam polyurethane. Doors and windows are generally covered with plastic sheets, which are cut into pieces with the same area as the doors and windows. For shelf tube, wrought iron and other irregular parts that need to be protected, they should be wrapped with plastic film for protection.

2. Spray polyurethane moisture-proof primer

Spray polyurethane moisture-proof primer evenly with a spray gun or roller brush for two times, with an interval of 2 hours. In wet weather, the time interval shall be appropriately extended, subject to the first time.

3. Spray rigid foam polyurethane insulation layer.

Start the polyurethane spraying machine to spray hard polyurethane evenly on the wall. Multi-layer spraying method: start spraying along the top corner of the wall, the top and bottom layers are 0.5mm first, and then spray several times, each layer is 20mm thick, forming polyurethane foam multi-layer foaming. Therefore, the thermal insulation effect of the cold storage is better, the strength of polyurethane foam is higher, and it will not crack and fall off.

4. Spray polyurethane interface mortar

After the polyurethane insulation layer is fully cured for 24-48h, the construction process of polyurethane interface mortar is carried out, and the polyurethane interface mortar is evenly sprayed on the surface of rigid foam polyurethane insulation layer with a spray bucket or roller brush. For uniform coverage, there shall be no splashing or brush leakage. After spraying polyurethane interface mortar 12-24h, the next process should be started. Be careful not to spray polyurethane interface mortar in rainy days.

5, hanging vertical line

At a distance of about 100mm from the top surface of the floor slab and about 100mm from the bottom surface of the floor slab, and at the same time at a distance of about 100mm from the internal or external angle of the big wall, vertical ash cakes (which should be completed by two people when the floor is high) are made as reference ash cakes, and then according to the connection line between the two vertical reference ash cakes,

Make the ash cake with the thickness of the wall leveling layer, and paste it every1.5m. The ash cake can be pasted with rubber powder polystyrene particle slurry or cut into small pieces of 50 mm× 50 mm.. After the vertical ash cake is fixed, pull the horizontal control line between two horizontal ash cakes. The specific method is to insert the small round nail with small thread into the ash cake, straighten the small thread, so that the control of the small thread is slightly higher than that of the ash cake 1mm, and paste some ash cakes or screed horizontally between the two ash cakes at an interval of about1.5m..

After each layer of ash cake paste construction is completed, check the consistency of ash cake with 5m string in horizontal direction, and check the verticality with 2m support plate in vertical direction, and measure the thickness of ash cake. The thickness of screed should be consistent with the thickness of ash cake. Check the consistency of leveling layer thickness with 5m string and make records.

6, leveling layer with rubber powder polystyrene particles

When plastering with rubber powder polystyrene particles thermal insulation slurry, the flatness deviation should not be greater than 4 mm, and the plastering thickness is slightly higher than that of ash cake. Thermal insulation mortar plastering should be carried out from top to bottom and from left to right. After plastering the whole wall, wipe it back and forth on the wall with a ruler to remove the high and make up the low. Finally, press it again with an iron trowel to make the surface smooth and the thickness consistent. The concave part of the insulation surface shall be leveled with dilute cement slurry, and the convex part shall be leveled with trowel. After plastering the thermal insulation surface for 30 minutes, it shall be plastered with a trowel, first horizontally and then vertically, and the acceptance standard shall be reached after inspection with a supporting ruler. During the construction of thermal insulation slurry, attention should be paid to cleaning the ground ash, and the ground ash should be re-stirred several times in a small amount in time.

7, laying galvanized steel wire mesh

After 72 hours, the insulation layer of rubber powder polystyrene particles was laid with galvanized steel wire mesh, and compacted with expansion nails and tablets. The pressing force of each nail should be uniform, and the steel mesh should be butted. The local gap between the steel mesh and the insulation layer shall not be too large. The butt joint of steel fabric shall be fastened with 200-250 pairs of 22# galvanized wires. The steel mesh butt joint at the external corner shall be bound with double-stranded 22# galvanized binding wire at the interval of 100- 150_, and the edge of the external corner shall be pressed firmly with expansion nails (note: the butt joint of steel mesh must be staggered by not less than 50mm). ) laying galvanized steel wire mesh anchor nail.

8. Crack-resistant gypsum

Use a trowel to smooth the prepared anti-crack plastering mortar from the center of the steel wire mesh to all sides. Steel wire mesh is immersed in mortar for leveling, and the construction is completed for 3-7 days. After the construction quality of insulation layer is qualified, the anti-crack layer construction can be carried out.

9. Allowable deviation items and inspection methods.