Study on the preparation and performance of water-based uncle fluoropropylate coatings

Water-based acrylic coating preparation and performance research
Gao Xiaohui
1
, Li Yufeng
2
,
Peng Ruihong
3
, Zhu Jingjing
1
, Zhou Mao
1
(1.
Qiqihar University School of Chemistry and Chemical Engineering
,
Heilongjiang Qiqihar
161006
;
2.
Qiqihar University School of Materials Science and Engineering
,
Heilongjiang Qiqihar
161006; 3. Qiqihar North Chemistry Co., Ltd., Heilongjiang Qiqihar 161002
acrylic coatings are applied to high-grade architectural coatings with the advantages of good film-forming, good color preservation, acid and alkaline resistance, water resistance, good scrub resistance, etc.

. However, there are also disadvantages such as high film temperature and low coating strength
the quality of
. Fluoropolymers have special surface energy, with fluorocarbon monomer modified acrylic coating performance is more excellent
(4-6)
, uncle carbon monomer has good shielding performance and film-forming properties, with fluorocarbons and uncle Carbon co-modified acrylic coatings have good weather resistance, durability, adhesion resistance, chemical resistance, acid and alkaline resistance, water resistance, wear resistance and corrosion resistance
China
. Paint fillers can provide the decorative color required by the coating, cover the ground floor, improve the performance of the paint film, improve the mechanical strength and corrosion resistance of the paint film, reduce the breathability and water permeability of the paint film. Coating additives mainly include wetting dispersants,
pH
regulators, antifreeze, film-forming additives, leveling agents, thickeners and so on. Together, these additives can improve film-forming properties and give the coating good stability
a good
. In this paper, the preparation method of hydrofluoropropylate coating is studied with the homemade acrylic emulsion as a film substance, and the effects of dispersive wetting agent, thickener,
pH
regulator, yanki ratio, solid content, emulsion type, etc. on coating performance are discussed. And the stability of the paint, paint film impact resistance, gloss, contact angle, water absorption rate and a series of performance is indicated.
1
1
Test Part
1.1
Test Raw Materials
Emulsion: Homemade; Wetting Agents: Industrial Grade, Shandong Rite Chemical Group Co., Ltd.; Sodium polychloride dispersants, polyacrylic pigment dispersants, hydrophobic Modified alkali-soluble thickener, polyurethane fluidization modifier: industrial grade, Dalian Jindingxiang Chemical Co., Ltd.;
1.2
coating preparation method
coating preparation process is divided into grinding, high-speed dispersion and painting.
1
) Grinding according to the formulation standard said to take the appropriate amount of wetting agents, dispersants, antifreeze and other additives dispersed in the water, add pigments, defrosting agents, fully stirred well, and then in
600 r/min
conditions grinding for half an hour to make slurry.
2
) Dispersedmoved to a high-speed dispersion machine, at a speed of
800 r/min
to add emulsion, film-forming additives, high-speed dispersion
10min
According to the example, the water solution with the appropriate amount of thickener is dispersed at high speed
10min
, so that the pigment particles are dispersed into primary particles at the high shear rate of the high-speed mixer and are dispersed and stabilized under the action of the dispersion aid.
3
) paint
moulation
pH
to moderate, low-speed stirring
10 min
to dispersion evenly, stirring process drops add the appropriate amount of defystant, completely eliminate bubbles, filter, material, get the final coating.
1.
3
test of coating performance
pours prepared paint dispersion into a
10ml
measuring barrel, sits
3h
, measures the sedation height of

, determines the volume of the coating, and uses static dithering to determine the volume of the coating at the contact angle (
JY-82
() the contact angle of water and glycol on the surface of the coating is determined, and according to the formula
X
s
(m
1
-

0
)/m
0
×100
% to determine the absorption rate of the coating,
X-
absorption rate;
m
1
-
quality of the film after immersion
/g
;
m
0
-
quality of the film before immersion
/g
, observe the shape of the coating on the scanning electron microscope
(S4300)
, determine the other properties of the coating according to national standards: solid content,
GB/T6751-1986
;
GB/6753.3-86
; Construction,
GB/T9755-2001
; Water resistance,
GB/T1733-1993
; alkaline resistance,
GB/T9265
; organic solvent resistance,
GB/T9274-88
; Glossy,
GB/T 9754-1988
; Pencil Hardness,
GB/T6739
; Flexible,
GB/T6742
; Adhesive,
GB/T9286-1998
, paint film shock resistance,
GB/T1732-1993
;Drying time,
GB/T1728-1979
(
1989
)
.11
.
2
results and discussion
2.1
the effect of film-forming substances on coating performance
As can be seen from Table
1
, from pure propylene coatings, fluorocarbon acrylates coatings to acrylic coatings, their water resistance, alkaline resistance, resistance to organic solvents and other properties have been significantly improved, contact angle and water absorption rate has also been significantly improved, indicating that the paint weather resistance, adhesion resistance has been improved. This is due to the positive correlation between the performance of the coating and the performance of the substing when the coating formulation is the same. After the introduction of fluorocarbon monosomals in pure propylene emulsions, the performance of emulsions has been improved, and the water resistance of coatings has been improved, and the performance of the coating has been further improved by the continued introduction of uncle carbon monosomes, indicating that the coatings prepared with fluorocarbon monotons and uncle carbon monosomes are the best for coating preparation as film-forming substances.2.2
Effect of the amount of wetting dispersant on coating performance
Wetting dispersant is gradually adsorbed to the surface of solid particles by ionizing in the coating system, resulting in a dual-layer structure with a certain
(ζ

)
. When the amount of wetting dispersant is insufficient, it is not enough to wet the surface of the particles, so that the solid particles are not fully dispersed, the system is viscous, and has a certain degree of tentacles, the section volume is large, fast, the dispersion effect is not good;
ζ
of the particles gradually increases, the rebuke produced by the double layer formed on the surface of the particles increases, and the joint action of the charge refring force and spatial resistance slows the collision between the solid particles, making the particles more easily dispersed and the system sticky. Degree decreases, sedation volume decreases, velocity decreases, when the concentration of wetting dispersant reaches the optimal value, the dispersion stability is the greatest, wetting is the best, the system is similar to Newtonian fluid, and can achieve short-term stability, and the continued increase of wetting dispersant will be due to Supersaturation adsorption causes the hydromassivity of the solid surface to decrease, which is not conducive to wetting and dispersion, and may even cause the double-layer's likeness to decrease due to the increase of cation
concentration, resulting in the reunion of particles
As shown
table
2, the optimal dosage for wetting the dispersant is
0.8%
.the degree of dispersion of pigment fillers can also be indicated by the gloss of the coating film

As can be seen from Figure
1
, when the amount of wetting dispersant reaches
0.8%
, the gloss is the highest, reaching
14.31
, and the amount of wetting dispersant continues to increase, which has little effect on gloss. It is shown that when the dispersant
0.8%
, the pigment has achieved a good dispersion effect.2.3
effect of pH
coating
pH has an effect on the molecular morphology and desociation of dispersants. As shown in Table
3
, when the
pH
is low, the wetting dispersant is almost non-dissoquent, at this time the wetting dispersant is present in a curly winding manner on the solid-liquid interface, and the adsorption layer is very Thin, almost bitless resistance, so the suspension viscosity and subsidence volume is larger, with the increase of
pH
, wetting the dispersant's dissociation increased, the static refruff between the chain sections makes it gradually stretch out, can be Static resistance is provided over a longer range, so the suspension has a small viscosity and a sethering volume of
,10 ,
, when the
pH
increases to
8
At the same time, the dispersion effect is more obvious, and from the change of gloss in Figure
2
, it can be seen that when the
pH
is
8
, the dispersion effect is better. 2.4
Effects of the type of thickener on coating performance
Cellulose ether thickeners (
HEC
) and acrylic-alkali-soluble thickeners (
HASE
) thicken water mainly through hydrogen bonds and chain windings between molecules. Polyurethane-connected thickeners (
HEUR
) thicken water and form a three-dimensional network structure by combining latex particles and pigment particles. However, due to the low molecular weight of the tangent-type thickener, the effective volume increase after hydration is less, and the entanglement between the molecules in the water phase
is limited, so the thickening multiplle is lower
As shown in
4
, the
HASE
(
203
) and
HEUR
(
003
) are best used. Thickener simultaneously thickens the water phase and contracts emulsion particles and pigment particles, which can make the system reach a long-term stable state, so that the system reaches a medium-low shear viscosity, which is conducive to leveling and preventing flow hanging. 2.5
The effect of thickener on coating performance
some table
5
shows that the amount of thickener directly affects the stability of the coating and coating performance. When the amount of thickener is small, the system viscosity is low, there is a slight flow, the stability is not ideal, with the increase of thickener, the molecular chain winding strengthens, forming a stable network structure, latex particles further expand, and pigment particles closely connected, the system viscosity increases, often Temperature stability and high temperature stability gradually improved, when the amount of thickener increased to
0.8%
of the system, coating performance and coating performance reached the best, continue to increase the amount of thickener, the system is very viscous, resulting in flocculation within the system. 2.6
Effect of the paint base ratio on paint performance
By scanning the electron microscope photo (Figure
3
), it can be seen that when the pigment is large, the base material is not sufficient to fill and moisturize solid particles, This results in tightly connected solid particles, uneven dispersion, poor coating performance (Figure
a
), when the face base ratio is less than hours, the free volume is not fully filled, the coating is a poor dryness, forming a trace crack
16)
(figure
c
); only the pigment ratio can be equal when near the critical volume concentration of the pigment (
CPVC
), so that the paint film performance is good (Figure
b
). In this paper, the method of pigment ratio is used to explore the determination of the amount and ratio of emulsions, pigments
and
. Yanji ratio has a greater impact on the performance of the coating, as can be seen from Figure
4
: With the increase of Yanjibi contact angle first increased and then decreased, water absorption first decreased, and then tend to stabilize, in Yanjibi