Application of polyurethane coatings in colored anti-slip pavement

summary

Color anti-slip pavement plays a vital role in beautifying the city, inducing traffic, alleviating road congestion and other fields, and the performance of the paint used directly affects the quality of the pavement, so it is of great significance
to study the application of polyurethane coatings in the color anti-slip pavement.
The effects of polyol types, functionality, hydroxyl values and viscosity on cement concrete bonding strength are discussed, and the properties
of three major types of resin coatings are compared.
The results show that aromatic polyols, high-functional polyols, polyols with high hydroxyl value and polyols with viscosity greater than 900cps (25°C) can enhance the adhesion strength of polyurethane coatings and cement concrete, and the comprehensive performance of polyurethane coatings is best coatingol.
com
on-line.

keyword

Polyurethane coating, color non-slip pavement; Ceramic granules; Polyols

introduction

The performance of resin coatings directly affects the road performance and life of color anti-slip pavement, while the performance of polyols is directly related to the properties of polyurethane coatings, so this paper studies the effect of polyol properties on the bonding strength of polyurethane coatings and cement consolidates, and compares the performance
of three major types of resin coatings.

1 Experiment

1.
1 Main raw materials and specifications

Polyols Sovermol 1140, Sovermol 908, Sovermol 818, Sovermol 810, Sovermol 815, Sovermol 1106, Sovermol 1102, Industrial Grade, BASF; Modified castor oil polyol A4812, AN2020, AN2010, AP-10, AP11, industrial grade, Shanghai Jingri New Material Technology Co.
, Ltd.
; Polyether ternyl alcohol MN-1000, industrial grade, Shandong Lanxing Dongda Co.
, Ltd.
; Heavy calcium carbonate (800 mesh), industrial grade, Guangxi Xin Calcium Mining Co.
, Ltd.
; Silane coupling agent KH-560, industrial grade, Hubei New Blue Sky New Materials Co.
, Ltd.
; Polyphenyl polymethylene polyisocyanate PM-200, industrial grade, Wanhua Chemical Group Co.
, Ltd.
; Various additives (defoamers, anti-settling agents, etc.
), industrial grade, domestic; Acrylic coatings, Shuangzhou brand, Changsha Shuangzhou Anticorrosion Materials Co.
, Ltd.
; Polyurethane coatings, CR-351, Guangzhou Jibisheng Technology Industrial Co.
, Ltd.
; Epoxy coatings, EP-402, Guangzhou Jibisheng Technology Industrial Co.
, Ltd.

1.
Preparation of 2-component polyurethane adhesive

The polyol, filler, etc.
are added to the 500ml four-mouth flask, heated to 120 °C for 3h, cooled to 50 ~ 70 °C, and a certain amount of defoamer, anti-settling agent and other additives are added to improve the stirring speed and mix evenly
.
A component of the polyurethane adhesive can be prepared
.
According to the R value to calculate the mass of the isocyanate (B component) required for complete curing of the A component, the B component obtained by weighing is added to the A component, stirred so that it is mixed evenly, and it can be used
.

1.
3 Performance test

The cement concrete bonding strength test is carried out
according to the method of GB/T16777-2008.

Adhesion strength test: cement concrete size (70×70×20)mm, with resin paint to the tensile fixture and the paint surface pasted together, carefully remove the surrounding overflowing paint, under standard test conditions horizontally placed cured for 24h
.
Then cut the film to the base layer with a knife along the edge of the upper fixture to make the test area (40×40)mm, and test the adhesion strength
according to GB/T16777-2008.

2 Results and discussion

2.
1 Effect of polyol type on cement concrete bonding strength

Result analysis: It can be seen from Table 1 that the adhesion strength of polyester polyols to cement concrete is stronger than that of polyether polyols, which is because the cohesion formed by ester bonds is stronger than that of ether bonds.
The adhesion strength of aromatic polyester polyols to cement concrete is stronger than that of aliphatic polyester polyols, which is because aromatic polyester polyols contain benzene rings, which have greater cohesion and stronger
adhesion strength than aliphatic polyester polyols.

2.
2 Effect of polyol functionality on cement concrete bonding strength

Result analysis: It can be seen from the figure that with the increase of polyol functionality, the adhesion strength of polyurethane coatings to cement concrete increases, this is because the greater the polyol functionality, the easier it is to react to form a body network structure, the greater the crosslinking density, the tighter the structure of the prepared polyurethane coating, the stronger the cohesion, and the greater
the bonding strength.
Polyols with a functional degree of 2 have the lowest adhesion strength to cement concrete because the resulting product is linear, the reaction forms a low crosslinking density and a small
adhesion force.

2.
3 Effect of polyol hydroxyl value on cement concrete bonding strength

Result analysis: As can be seen from Figure 2, in the range of hydroxyl value (45~210mgKOH/g), the adhesion strength of polyurethane coating to cement concrete is enhanced
with the increase of hydroxyl value.
This is because with the increase of the hydroxyl value, the more isocyanate is required, the larger the hard segment contained in the polyurethane structure, the more polar group content, the intermolecular force is enhanced, that is, the wetting performance of the polyurethane on the surface of the cement concrete is improved, and the cohesion of the polyurethane itself is increased, so the stronger the adhesion strength of the cement consolid
.

2.
4 Effect of polyol viscosity on cement concrete bonding strength

Result analysis: It can be seen from Figure 3 that the viscosity of polyols has a great influence on the bonding strength of cement concrete, and with the increase of polyol viscosity, the bonding strength of cement concrete is first enhanced, and then stabilized
.
This is because when the polyol viscosity is too low, when the polyurethane coating is coated on the cement concrete, the polyol can easily penetrate into the porous cement concrete, resulting in only the powder of the polyurethane coating remaining on the surface of the cement concrete, which seriously affects the adhesion strength
of the cement concrete.
When the viscosity of the polyol is above 900MPa·s (25 °C), the polyol basically no longer penetrates into the interior of the cement concrete, and the bonding strength of the cement concrete is greatly enhanced
.

2.
5 Comparison of acrylic coatings, polyurethane coatings and epoxy coatings

Result analysis: It can be seen from Table 2 that the low viscosity of acrylic coatings leads to easy delamination, weak adhesion, and cannot meet the standard JT/T712-2008 requirements for binder adhesion (≤ 4 grade), so when used in colored anti-slip pavement, it is necessary to increase the covering process
.
However, the drying time of non-stick tires is short, which shortens the sealing time
.
Epoxy coatings have strong adhesion and reach grade 1, but the low temperature resistance is poor, and cracks appear in the coating
.
Polyurethane coatings have the best low temperature resistance and strong adhesion, and the comprehensive performance is the best
in these three major types of coatings.

3 Conclusion

(1) The bonding strength of polyester polyols is stronger than that of polyether polyols, and the bonding strength of aromatic polyester polyols is stronger than that of aliphatic polyester polyols
.

(2) When the same polyol is of the same species, with the increase of the functionality of the polyol, the adhesion strength of the polyurethane coating to the cement concrete increases
.

(3) In the range of a certain hydroxyl value, the adhesion strength of the polyurethane coating to cement concrete is enhanced
with the increase of the hydroxyl value.

(4) The viscosity of polyols has a great influence on the bonding strength of cement concrete, and with the increase of polyol viscosity, the bonding strength of cement concrete is first enhanced, and then stabilized
.

(5) Acrylic coatings have low viscosity, weak adhesion and short initial solidification time; Epoxy coatings have strong adhesion and poor low temperature resistance; Polyurethane coatings have strong adhesion, good low temperature resistance and the best
comprehensive performance.