The Influence of Co/Sr and Fe/Sr Driers on Film Formation of High Solid Alkyd Coatings

W2085476263 · 수집 2026-10-04 18:12:19

T10409 Fuel Cells and Related Materials

CoT 라벨링

라벨링 전

PDF 파일

자동 다운로드한 PDF PDF 보기

기본 정보

DOI 제목 발행년도 저널 URL 페이지 열기 PDF URL PDF 열기 발행기관 피인용수 라이선스

추가 정보 초록

High solid (HS) alkyd resins with low amount of volatile organic compounds (VOC) were developed as the result of new VOC solvent directive that limit the amount of VOC in decorative paints. Due to specific chemical structure of HS alkyd resins and possible deterioration of some applicative properties the optimal combination of driers is an important subject of research. In our present work we studied the influence of iron (Fe) and cobalt (Co) surface driers with strontium (Sr) through drier on the film formation of HS alkyd coatings. The kinetics of autoxidation was analysed using FT-IR spectroscopy. Further, applicative properties like drying time and film hardness were examined. In the end, electrochemical impedance spectroscopy (EIS) was used to evaluate the quality of cured HS alkyd coating films after exposure in the humidity chamber. It was established that the addition of the Sr drier to surface driers accelerates the film formation process. As higher amounts of the Sr drier were added, final drying times were reduced and film hardness increased. The highest quality of cured films were observed for Co/Sr and Fe/Sr drier combination at 1:1 concentration ratio.

본문

52 _Acta Chim. Slov._ 2015, _62,_ 52–59

DOI: 10.17344/acsi.2014.708

_Scientific paper_

# The Influence Of Co/Sr and Fe/Sr Driers on Film Formation of High Solid Alkyd Coatings
## Barbara Pir{, 1, * Bogdan Znoj, 1 Sa{a Skale, 2 Jo`efa Zabret, 1 Jerneja Godnjavec, 3 Peter Berce 1 and Peter Venturini 2

1 _Helios TBLUS, d.o.o., Kolicevo 65, 1230 Dom`ale, Slovenia._

2 _Helios Dom`ale d.d., Koli~evo 2, 1230 Dom`ale, Slovenia._

3 _Center of Excellence for Polymer Materials and Technologies, Tehnoloski park 24, 1000 Ljubljana, Slovenia._

_* Corresponding author: E-mail: barbara.pirs2_ _@_ _helios.si_

_Received: 04-06-2014_

## Abstract

High solid (HS) alkyd resins with low amount of volatile organic compounds (VOC) were developed as the result of
new VOC solvent directive that limit the amount of VOC in decorative paints. Due to specific chemical structure of HS
alkyd resins and possible deterioration of some applicative properties the optimal combination of driers is an important
subject of research. In our present work we studied the influence of Fe bispidon (Fe drier) and Co ethylhexanoate (Co
drier) surface driers with Sr carboxylate (Sr drier) through drier on the film formation of HS alkyd coatings. The kinetics of autoxidation was analysed using FT-IR spectroscopy. Further, applicative properties like drying time and film
hardness were examined. In the end, electrochemical impedance spectroscopy (EIS) was used to evaluate the quality of
cured HS alkyd coating films after exposure in the humidity chamber. It was established that the addition of the Sr drier to surface driers accelerates the autoxidation process. As higher amounts of the Sr drier were added, final drying
times were reduced and film hardness increased. The lowest diffusivity of ions through cured HS alkyd coating films
was observed for Co/Sr and Fe/Sr drier combination at 1:1 concentration ratio.

Keywords: HS alkyd coatings, drier, Sr, FT-IR, EIS

## 1. Introduction

Alkyd coatings are complex mixtures based on
alkyd polymers, which have both a decorative and a protective function. The term coating describes a liquid material that is applied to a substrate, after application of
which a formed solid coating film results. The formation
of a film is a process where physical and chemical
changes occur. 1,2 Chemical changes are the consequence
of a free-radical reactions known also as autoxidation.
The reactions are usually catalysed using a combination
of organic metal salts known as driers. Driers are typically classified by function as surface, through and auxiliary
driers. 3,4 Surface driers exert a catalytic effect and accelerate surface drying. Through driers promote curing beneath the surface of the coating and improve the stability
of the surface driers. They form oxygen-metal-oxygen
crosslinks by reacting hydroxyl and carboxyl groups with

polymer molecules, which contribute to the through-drying process. 4,5 Auxiliary driers inhibit phase separation
from the coating surface. 4 To assure optimal film formation, coatings usually contain a mixture of all three types
of driers. 5 The amount of driers needed is system specific
and should be kept to the minimum possible level. 3,6

Alkyd polymers are used in alkyd coating formulations due to their low cost and versatility. They belong to a
group of environmentally friendly resins whereas most of
the constituents belong to renewable raw materials, except
for phthalic anhydride which is of petrochemical origin. 7

Recently HS alkyd resins with reduced contents of organic solvent were developed in the face of new requirements
in EU environmental legislation. 1,2 The introduction of
new or modified polymers is often associated with the deterioration of several applicative and performance coating
properties. In the case of HS alkyd coatings, deterioration
exhibits as poorer drying performance. This is manifested

_Acta Chim. Slov._ 2015, _62,_ 52–59 53

in prolonged Set-to-Touch Times, poor Through Drying,
and as a consequence lower film hardness. 7 For this reason most research until now has been focused on the testing of alternative surface dryers and combination with
through driers. 8 It has been found that drier combinations
in HS alkyd resins behave differently than in conventional
alkyd resins. 1 Hein R.W for HS coatings has recommended that concentration levels of the through drier should be
increased. Further, he suggested avoiding the combination
Co/Ca driers due to Ca’s promotion of Co activity and the
resulting premature top drying. He also proposed the use
of through driers neodymium (Nd) and aluminium (Al)
since they exhibit better performance in HS coatings than
zirconium (Zr). 7 Muizebelt W. J. et. al. determined that the
addition of Al complexes in HS alkyd coatings provides
enhanced drying, grater hardness and better gloss; on the
downside, however, the coatings become brittle when exposed outdoor weathering. 8 Hein R. W. indicates a combination of Co/Nd + bipyridine (bpy) as the best combination
of HS alkyd resins. 1

Interesting catalytic properties can also be observed
with Fe surface drier. It reacts on the surface and through
the coating, which makes it interesting for use in HS alkyd
coatings. 9

In our work we made a comparative study of the influence of Fe/Sr and Co/Sr driers on the autoxidation curing process of HS alkyd coatings. Later we evaluate drying performance, hardness and finally the characteristics
of cured coating film by EIS.

## 2. Experimental

2. 1. Materials and Sample Preparation
We used the following components in the preparation of coatings: resin, driers, anti-skinning agents and a
solvent. Synolac 4047 WD 90, a long oil alkyd resin with
low VOC was used as a resin, supplied by Cray Valley (90
wt. % of solid content based on orto-phthalic acid anhydride, polyol-pentaerythritol and linoleic rich fatty acids).

As driers we used a commercially available Fe drier
(Fe bispidon) (Figure 1), supplied by OMG (Borchi Oxy
Coat with 1 wt. % of Fe complex in 1,2-propylene glycol)
and a commercially available Co drier also obtained from
OMG (Co bis (2-ethylhexanoate) with 10 wt. % of Co).

As a through drier we used a Sr drier (Sr carboxylate with
18% Sr) supplied by ROCKWOOD.
An anti-skinning agent (Methyl Ethyl Ketoxime –
MEKO) was added to prevent the skinning of coatings in
closed containers.

Samples were prepared by adding individual components (driers, anti-skinning agent and solvent) to an
alkyd resin and mixed with a propeller stirrer for 10 minutes at room temperature. The amount of used resin was
83 wt. %. The addition of MEKO was 0.7 wt. %. The rest
of the mixture consisted of non-aromatic solvent Shellsol
D-40 that was added to adjust the viscosity of the coating
between 0.7–1.0 Pas.

Surface driers were added in accordance with producer recommendations. Therefore we used 0.78 wt. % of
Fe drier and 1 wt. % of Co drier on resin solid content. A
Sr through drier was added in three different ratios (1:1,
1:3.5 and 1:10) to the Co and Fe driers. Tests were performed after 24 hours of sample storage. The sample
names are composed from the combination of surface/through drier and their ratio (e.g. Fe/Sr (1:3.5).

2. 2. Analytical Methods

The influence of Co and Fe driers on HS alkyd coating
characteristics was analysed by different analytical methods.

Time-resolved FT-IR spectra were obtained using a
Thermo Nicolet 6700 spectrometer and the transmission
technique (KBr crystal, range 400–4000 cm –1, resolution
4 cm –1 ). Coating samples were applied on a KBr crystal
plate with 7 μm spiral film applicator. A FT-IR spectrum
was measured every 30 minutes. In the meantime samples
were placed in the conditioner at 23 °C and 50 % humidity. We monitored the peaks at 3007 cm –1 ( _cis_ -C=C-H
stretching) and 3450 cm –1 (-O-H stretching) normalized
against the ester peak at 1272 cm –1 (-COOC stretching)
versus time. Relative reaction rates of radical initiated
crosslinking were calculated after the induction period
with a linear regression as ln (At/A0*100) versus time.

Drying performance was determined by BYK drying recorder according to ASTM D5895-03. Coating samples were applied to plain glass of approx. 60 μm wet film
thickness. The instrument included needles that travel on
the plain glass with coating test strip within a chosen
range of time – in our case 6 h. Different trace formations
on the coating film were evaluated to define different
stages of the film formation process.

To determine hardness of a coating surface film the
standard König method was used according to ISO 1522.
Coating samples were applied to plate glass with an applicator (wet film thickness of 60 μm). Successive measurements were taken after 1, 3, 7, 14, 21 and 28 days of drying. The results were determined as glass standard hardness and expressed as relative hardness.

Electrochemical impedance spectroscopy (EIS) is
Figure 1. Ligand bispidon. 9 an established quantitative method for anticorrosion ex

54 _Acta Chim. Slov._ 2015, _62,_ 52–59

amination of coating films. In our research we used EIS to
evaluate the quality of the HS alkyd coatings after curing
process with different combinations of driers. Coating
samples were applied on metal plates by spraying in three
layers over three consecutive days. The final cured film
thickness was measured with an Elcometer 456 (F1 magnetic induction probe from Elcometer Ltd.) and average
determined values were between 72 μm and 88 μm. For
each sample 15 measurements were taken in compliance
with the ISO 2178 standard. Prepared samples remained
in the conditioner for 5 days at 23 °C and 50% humidity.
The samples were then placed in humidity chamber
Ericssen HIGROTHERUS 519 for 4 h (T was 40 ± 0.5 °C
and relative humidity was maintained at 95 ± 0.5%) after
which they were measured by EIS. All EIS measurements
were carried out in duplicate.

EIS measurements were performed using a Parstat
2273 potenciostat. The measuring cell was a standard
three-electrode Tait-cell, consisting of a working electrode of 32 cm 2 immersed in 0.1M NaCl solution, a
Hastelloy counter electrode and a standard calomel reference electrode (SCE). The potential difference between
the working and counter electrode was – 0.6 V versus
SCE with signal amplitude of 30 mV. Data were collected
and analysed using Electrochemistry Power Suite and
PowerSINE software (Princeton Applied Research, USA).
Impedance spectra analysis was performed after numerical fitting using an equivalent electrical circuit, presented
in Figure 2.

Figure 2. Assumed equivalent electrical circuit for HS alkyd coatings with different drier combinations.

## 3. Results and Discussion

3. 1. Time Resolved FT-IR Experiment:
Evaluation of Chemical Curing

Chemical curing of HS alkyd coatings as a part of
film formation process was monitored by FT-IR spectroscopy. From the FT-IR spectra of HS alkyd coating
shown in Fig. 3 we can observe different band assignments that belong to chemical groups or bonds. 9 Our research was focused on peaks at 3450 cm –1, 3007 cm –1 987
cm –1, 970 cm –1 and 948 cm –1, which were changing during the autoxidation curing process of HS alkyd coatings .

Generally, autoxidation is a process in which atmospheric oxygen reacts with double bonds of unsaturated

Figure 3. FT-IR spectra of HS alkyd coatings with Fe surface driers
versus time.

fatty acid from alkyd resins. 1,3 The reactions of autoxidative curing process can be seen from Fig. 4. Important
chemical changes are related to unsaturated double bonds.
We used HS alkyd resin with linoleic acid that contain isolated _cis_ double bonds what can be seen in FT-IR spectra
from band at 3007 cm –1 ( _cis_ -C=C-H stretching).

Film formation of alkyd coatings starts with an induction period where evaporation of solvent and oxygen
absorption takes place. Further delocalization of isolated
_cis_ double bonds occurs due to hydrogen abstraction,
which induces the reaction with oxygen and the formation
of hydroperoxides (-OH band at 3450 cm –1 ). During the
reaction isolated cis double bonds (band at 3007 cm –1 )
transform to conjugated _trans_ double bonds (band at 987
cm –1 and 948 cm –1 ). Hydroperoxides (band at 3450 cm –1 )
then decompose into alkoxy and hydroxy radicals. 9

Crosslinking reactions further occur when conjugated
_trans_ double bonds transform to isolated _trans_ double
bonds (band at ∼ 970 cm –1 ). During the process intermolecular linkages are formed, which lead to a network formation and increased viscosity. Byproducts of decomposition like aldehydes, ketones and carboxylic acids are also formed by side reactions. 3,4,9,16

In our study of HS alkyd curing it was initially observed that surface driers have significant influence on formation of hydroperoxides what is evident from –OH group
changes (Fig. 5). However, –OH groups are present also in
the coating from the start of curing because the driers are
diluted in different alcohol-based solvents. In order to evaluate the formation of hydroperoxide during the autoxidation process the –OH groups from solvents were considered as the initial value of –OH group in Equation 1:

( _At – At=_ 0)/ _A_ 0 (1)

_At_ = area of –OH groups versus time

(band at 3450 cm –1 )

_At=_ 0 = initial value of area of –OH

groups (band at 3450 cm –1 )

_A_ 0= normalized peak (band at 1272 cm –1 )

_Acta Chim. Slov._ 2015, _62,_ 52–59 55

Figure 4. Shematic presentation of the autooxidative curing process in alkyd coatings. 9,16

The most intensive formation of hydroperoxides
was observed for HS alkyd coatings with Co drier, what
can be attributed to higher catalytic activity of Co. 4,6 The
diffusion of oxygen in the coating film start at the end of
the induction period and declines with the outset of coating film solidification (Fig. 5). 21 In all tested samples hydroperoxides start to form after induction time. Once the
formation of hydroperoxide ends the coating surface solidifies and the concentration of –OH groups remain
constant.

When using surface driers alone, the HS alkyd samples achieve higher hydroperoxide concentrations in com

Figure 5. Monitoring of -OH group (band at 3450 cm –1 ) during autoxidation process of HS alkyd coatings with different drier combinations.

parison with Co/Sr and Fe/Sr drier combinations. Higher
Sr drier ratios result in less hydroperoxide formation.
With Co/Sr and Fe/Sr drier combinations hydroperoxides
start to decompose earlier and faster than in cases using
only surface driers. Co/Sr drier combinations exhibit
faster hydroperoxide decomposition than Fe/Sr drier combinations.

The chemical curing of HS alkyd coatings was
further analysed from transformation of _cis_ -C=C-H
double bonds (band at 3007 cm –1 ). 10,22,23 FT-IR spectra
of HS alkyd coatings were recorded after different
times. Relative reaction rates have been calculated with
linear regression of the ln (At/A0*100) versus time after
the induction period. The changes during chemical curing of HS alkyd coatings are quantitatively presented in
Table 1.

Induction time is the period during which the peak
at 3007 cm –1 remains unchanged. 21 For samples with only
surface Co driers induction times lasted ≈ 1 h and for surface Fe drier ≈ 3 h. With the addition of a Sr drier induction times were reduced considerably (Table 1).

Relative reaction rates were higher with Co than
with Fe surface drier. The addition of Sr to the Co drier increases the reaction rate. An adverse effect of Sr drier was
observed in combination with a Fe drier, where reaction
rates were similar to the samples with only Fe drier.
However in the case of Fe/Sr (1:10) driers the reaction
rate slows down considerably.

56 _Acta Chim. Slov._ 2015, _62,_ 52–59

Table 1. FT-IR related data.

Reaction rate (h –1 ) Increase of Increase of
Coating Induction time

(Isolated cis- conjugated _trans-_ isolated _trans_ samples (h)
double bonds) double bonds (h) double bonds (h)

Co 1.0 ± 0.3 1.039 ± 0.051 2.5 ± 0.3 3 ± 0.3
Co/Sr (1:1) 0.5 ± 0.3 1.123 ± 0.029 2.0 ± 0.3 2.75–3 ± 0.3
Co/Sr (1:3.5) 0.5 ± 0.3 1.156 ± 0.043 1.5 ± 0.3 2.5–2.75 ± 0.3
Co/Sr (1:10) 0.5 ± 0.3 1.178 ± 0.026 1.5 ± 0.3 2.5 ± 0.3
Fe 3.0 ± 0.3 0.272 ± 0.015 5.0 ± 0.3 >7 ± 0.3
Fe/Sr (1:1) 2.0 ± 0.3 0.275 ± 0.009 5.0 ± 0.3 >7 ± 0.3
Fe/Sr (1:3.5) 2.0 ± 0.3 0.267 ± 0.003 4.5 ± 0.3 >7 ± 0.3
Fe/Sr (1:10) 2.0 ± 0.3 0.174 ± 0.005 5.5–6.5 ± 0.3 >7 ± 0.3

Further chemical changes due to the autoxidation
mechanism can be traced along the FT-IR peaks of conjugated _trans_ -C=C-H double bonds and isolated _trans_ -C=CH double bonds. The band of conjugated _trans_ -C=C-H
double bonds (at 987 cm –1 and 948 cm –1 ) increases for a
few hours, after which it starts to decrease. However, isolated _trans_ -C=C-H increases over the entire chemical curing process, what indicates that crosslinking is taking
place (Fig. 6). 9

Faster conversion of conjugated to isolated _trans_   C=C-H double bonds can be observed (Table 1) by addi

Figure 6. Detailed and shifted FT-IR spectra of HS alkyd coatings
with Co/Sr (1:10) drier- combinations versus time.

tion of Sr drier to the Co drier. On the other hand the starting times for formation of conjugated and isolated _trans_ C=C-H double bonds are similar for HS alkyd coatings
with Fe/Sr drier combinations. The only exception is the
combination of driers Fe/Sr (1:10) where the formation of
conjugated and isolated _trans_ -C=C-H double bonds was
starting later.

It was also seen that isolated _trans_ -C=C-H bonds increase after the induction period what can be a consequence of crosslinking via direct addition of radicals to
double bonds according to Oyman. 3

From these results we can confirm that the addition
of Sr as a through drier reduces induction time and accelerates the autoxidation process.

3. 2. Drying Time

Drying time is a process of different drying stages
by which we monitor transformation of the applied liquid
coating into a solid coating film. 1 Drying performance of
HS alkyd coatings was determined using a BYK drying
recorder according to ASTM D5895-03. 24 In our case we
focused on Set-to-Touch Time and Final Drying Time
stages. The results are presented in Table 2.

Set-to-Touch Times decreases with the increased ratio of Sr through drier compared to the HS alkyd coatings
where only a surface drier was used (Table 2). Co/Sr and
Fe/Sr (1:10 ratio) drier combinations exhibited the short

Table 2. Set-to-Touch Time, Final Drying Time values and Relative film coating hardness after 28
days for HS alkyd coatings using different drier combinations.

Coating Set-to-Touch Time Final Drying Time Film hardness after
samples (h) (h) 28 days (%)

Co 2.7 ± 0.2 - 6 ± 0.2 104 ± 3
Co/Sr (1:1) 2.7 ± 0.2 5.8 ± 0.2 132 ± 3
Co/Sr (1:3.5) 1.6 ± 0.2 5.1 ± 0.2 137 ± 3
Co/Sr (1:10) 1.2 ± 0.2 4.7 ± 0.2 150 ± 3
Fe 3.5 ± 0.2 5.5 ± 0.2 45 ± 3
Fe/Sr (1:1) 2.6 ± 0.2 4.3 ± 0.2 46 ± 3
Fe/Sr (1:3.5) 1.5 ± 0.2 4.3 ± 0.2 49 ± 3
Fe/Sr (1:10) 1.1 ± 0.2 3.8 ± 0.2 67 ± 3

_Acta Chim. Slov._ 2015, _62,_ 52–59 57

est Set-to-Touch Times. Final Drying Times were reduced
with the addition of a Sr through drier. The shortest Final
Drying Times were observed for Fe/Sr (1:10) combination. Due to reduced curing rate, we assume that the faster
drying time was a consequence of faster skin layer
growth. 19

3. 3. Hardness

Hardness values for HS alkyd coatings were measured by König method that evaluates the surface hardness
of dried coating film. Higher Sr concentration in combination with surface driers enables higher hardness values of
coatings than those using only surface driers (Table 2).
Hardness values for the samples with Co drier combinations were significantly higher than with Fe drier. Boer at.
al. in his paper stated reduction in hardness, in case of use
Fe-bispidon drier in HS alkyds.The addition of a Sr drier
improves film hardness in combination with a Co drier.
However, in combination with a Fe drier has less impact
on surface film hardness.

The differences between Co/Sr and Fe/Sr drier combinations are due to differences of surface drier activity. In
the literature it was confirmed that Co drier does not
crosslink homogeneously along the depth of an alkyd film
due to the very high catalytic activity on the surfaces. 3 For
Fe drier it is also known, that poses through drying effect. 4

Electrochemical impedance spectroscopy (EIS)
In order to evaluate the influence of different Co/Sr
and Fe/Sr drier combinations on curing of HS alkyd coatings, impedance spectra of dried coating films were measured after exposure in the humidity chamber. A Nyquist
plot of impedance spectra along with fitting curves is displayed in Fig. 7. By comparing the inclination and the
shape of the impedance curves it can be concluded that the
addition of Sr drier generally has an adverse effect on barrier properties of the coatings as determined by EIS.
However, by examining individual elements of the equivalent circuit a more profound understanding of Sr drier influence on coating properties can be attained.

Figure 7. Nyquist plot of EIS measurements and equivalent circuit
model for HS alkyd coatings of different drier combinations.

In order to reduce the effect of coating thickness
variation, characteristic properties of the equivalent circuit elements were converted to thickness independent
quantities. Coating capacitance, Warburg coefficient,
pore resistance and coating thickness were thus used to
obtain dielectric constant εc, the product of Warburg
diffusion coefficient with film thickness σc · dc and specific pore resistance ρpo. 25 Results are presented in
Table 3.

Exposure in the humidity chamber resulted in an increase of the dielectric constants for all coating samples,
which is an indication of water absorption. 25 Dielectric
constants can be used to estimate the amount of absorbed
water. 26 In the case of investigated samples water absorption was estimated to be about 1–2 vol %. Larger increases were observed in samples which contained only surface
Fe and Co driers. Samples with Fe/Sr drier combinations
displayed lower values of dielectric constants than samples with Co/Sr combinations (Table 3).

Table 3. EIS parameters after 4 h after exposure in the humidity chamber.

Coating σ c*dc ρ po
ε c (/)
samples (10 –6 Ω –1 rad –1/2 s 1/2 μm) (10 3 Ω /μm)

Co 7.1 ± 0.3 0.95 ± 0.08 2669 ± 249
Co/Sr (1:1) 6.3 ± 0.3 0.41 ± 0.03 763 ±53
Co/Sr (1:3.5) 6.0 ± 0.2 0.57 ± 0.03 328 ± 16
Co/Sr (1:10) 6.3 ± 0.5 19.11 ± 2.02 16 ± 1
Fe 7.2 ± 0.4 0.35 ± 0.05 1551 ± 267
Fe/Sr (1:1) 4.5 ± 0.3 0.19 ± 0.02 357 ± 24
Fe/Sr (1:3.5) 4.6 ± 0.2 0.30 ± 0.02 184 ± 7
Fe/Sr (1:10) 4.6 ± 0.2 0.51 ± 0.02 55 ± 2

- ε c = relative dielectric constant, σ c* d c = product of Warburg coefficient and film tickness, ρ po =
pore resistance

58 _Acta Chim. Slov._ 2015, _62,_ 52–59

The product σc - dc represents diffusion of ions of
the supporting electrolyte through the coating film.
Higher values of σc · dc correspond to higher diffusivity of
ions through the polymer matrix. 27 Differences in
Warburg diffusion were observed between coatings with
different drier combinations (Table 3). The addition of Sr
through drier to surface driers at ration 1:1 induces lower
diffusivity of ions through the cured coating film however
further increase of Sr through drier result in increased
Warburg diffusion. The lowest diffusivity of ions was determined also for Fe drier what can be explained by homogeneous crosslinking through the depth of the coating
film. 28 Pore resistance comparison shows that higher concentrations of Sr through drier correspond to higher film
porosity.

## 4. Conclusions

HS alkyd resins have specific chemical structures
that influence also on physical and chemical changes of
HS alkyd coatings during curing process; however, they
can be optimised with the combination of surface and
through driers. In our case we studied Co and Fe surface
driers in combination with a Sr through drier and their impact on alkyd coating film formation properties.

Chemical changes in HS alkyd coatings were observed by FT-IR according to the autoxidation mechanism. Due to changes in FT-IR spectra it was established
that the formation of hydroperoxides is slower in HS coatings with Fe surface drier compared to Co surface driers.
The addition of a Sr through drier increases the decomposition of hydroperoxides in combination with both surface
driers. Similar behaviour was also observed by comparing
induction drying times. Further we established that the
transformation of _cis_ -C=C-H double bond was higher in
HS coatings with Co drier combinations. Sr through drier
in combination with a Co surface drier increases the transformation reaction rates. The same behaviour was observed with higher ratio of Sr through drier. On the other
side, lower concentrations of Sr through drier in combination with Fe drier did not have significant effect on transformation of _cis_ -C=C-H reaction rates. The exception is
only Fe/Sr (1:10) combination where important decrease
of transformation reaction rate was observed.

In terms of physical changes higher values of König
hardness were determined for HS alkyd coatings with a
Co surface drier compared to Fe surface driers. The addition of a Sr through drier increases hardness values and reduces film formation drying times.

Cured coating film characteristics were finally evaluated by comparing EIS overall equivalent circuit parameters. HS alkyd samples with Co/Sr and Fe/Sr drier combinations exhibited comparable water absorption levels.
Low ratio of Sr driers to surface driers decreases the diffusion of ions through the coating film. The lowest diffusion

of ions was achieved with 1:1 ratio of Fe/Sr driers, which
confirm higher through drying activity of Fe drier. All
measured samples developed pores.

## 5. Acknowledgements

“Operation part financed by the European Union,
European Social Found. Operation implemented in the
framework of the Operational Program for Human
Resources Development for the Period 2007-2013,
Priority axis 1: Promoting entrepreneurship and adaptability, Main type of activity 1.1: Experts and researchers for
competitive enterprises.”

## 6. References

1. Z. W. Wicks Jr., F. N. Jones, S. P. Pappas, D. A. Wicks,
Organic coatings: Science and technology, 3 rd. WileyInterscience, Hoboken, New Jersey, 2007 .

http://dx.doi.org/10.1002/047007907X
2. A. Overbeek, F. Bückmann, E. Martin, P. Steenwinkel, T.
Annable, _Prog. Org. Coat._ 2003, _48_, 125–139.

http://dx.doi.org/10.1016/S0300-9440(03)00101-2
3. Z. O. Oyman, PhD thesis, _Technische Universiteit Eindho-_
_ven, Eindhoven, Netherlands_, 2005 .
4. M. D. Soucek, T. Khattab, J. Wu, _Prog. Org. Coat._ 2012, _73_,
435–454.
http://dx.doi.org/10.1016/j.porgcoat.2011.08.021
5. R.W. Hein, _J. Coat. Technol. Res._ 1998, _70 (886)_, 19–22.
http://dx.doi.org/10.1007/BF02697848
6. J. Lindeboom, _Prog. Org. Coat._ 1998, _34_, 147–151.
http://dx.doi.org/10.1016/S0300-9440(98)00034-4
7. A. Hofland, _Prog. Org. Coat._ 2012, _73_, 274–282.
http://dx.doi.org/10.1016/j.porgcoat.2011.01.014
8. C. Pilemand, E. Wallström, P. B. Poulsen, _Eur. coat._ 2005, _2_,
7–20.
9. J. W. de Boer, P. V. Wesenhagen, E. C. M. Wenker, K.
Maaijen, F. Gol, H. Gibbs, R. Hage, _Eur. J. Inorg. Chem._
2013, 3581–3591.
http://dx.doi.org/10.1002/ejic.201300205
10. Z. Liu, H. Kooijman, A. L. Spek, E. Bouwman, _Prog. Org._
_Coat._ 2007, _60_, 343–349.

http://dx.doi.org/10.1016/j.porgcoat.2007.08.003
11. S. T. Warzeska, M. Zonneveld, R. Van Gorkum, W. J.
Muizebelt, E. Bouwman, J. Reedijk, _Prog. Org. Coat._ 2002,
_44_, 243–248.
http://dx.doi.org/10.1016/S0300-9440(02)00057-7
12. J. Z. Wu, E. Bouwman, J. Reedijk, _Prog. Org. Coat._ 2004,
_49_, 103–108.
http://dx.doi.org/10.1016/j.porgcoat.2003.08.019
13. M. Erben, D. Veselý, J. Vinklárek, J. Honzí~ek, _J. Mol._
_Catal. A: Chem._ 2012, _353–354_ 13–21.

http://dx.doi.org/10.1016/j.molcata.2011.10.024
14. V. Stava, M. Erben, D. Vesely, P. Kalenda, _J. Phys. Chem._

_Acta Chim. Slov._ 2015, _62,_ 52–59 59

_Solids._ 2007, _68_, 799–802.

http://dx.doi.org/10.1016/j.jpcs.2006.11.019
15. O. Preininger, J. Honzí~ek, J. Vinklárek, M. Erben, _Prog._
_Org. Coat._ 2014, _77_, 292–297.

http://dx.doi.org/10.1016/j.porgcoat.2013.10.001
16. R. Van Gorkum, E. Bouwman, _Coord. Chem. Rev._ 2005, _249_,
1709–1728.
http://dx.doi.org/10.1016/j.ccr.2005.02.002
17. R.W. Hein, _J. Coat. Technol. Res._ 1999, _71(898)_, 21–25.
http://dx.doi.org/10.1007/BF02698429
18. W. J. Muizebelt, J. C. Hubert, R. A. M. Venderbosch, A. J. H.
Lansberger, R. P. Klaasen, K. H. Zabel, _J. Coat. Technol._
Res. 1998, _70 (882)_, 53–59.

http://dx.doi.org/10.1007/BF02720515
19. S. J. F. Erich, PhD thesis, _Technische Universiteit Eind-_
_hoven, Eindhoven, Netherlands_, 2006 .
20. S. M. P. Meneghetti, R. F. de Souza, A. L. Monteiro, M.O de
Souza, _Prog. Org. Coat._ 1998, _33_, 219–224.

http://dx.doi.org/10.1016/S0300-9440(98)00058-7
21. P. Mischke, Film Formation in Modern Paint Systems,
Vincentz, Hannover, Germany, 2010 .

## Povzetek

22. G. Ye, F.Courtecuisse, X. Allonas, C. Ley, C. CroutxeBarghorn, P. Raja, P. Taylor, G. Bescond, _Prog. Org. Coat._
2012, _73_, 366-373.
http://dx.doi.org/10.1016/j.porgcoat.2011.03.015
23. E. Bouwman, R. Van Gorkum, _J. Coat. Technol. Res_ . 2007, _4_
_(4)_, 491–503.

http://dx.doi.org/10.1007/s11998-007-9041-0
24. ASTM international, Standard test methods for evaluating
drying or curing during film formation of organic coatings
using mechanical recorders, Designation: D 5895 – 03, 1–4.
25. S. Skale, V. Dole~ek, M. Slemnik, _Prog. Org. Coat._ 2008,
_62_, 387–392.
http://dx.doi.org/10.1016/j.porgcoat.2008.02.003
26. A.S. Castela, A.M. Simoes, _Corros. Sci._ 2003, 45, 1631–
1646.
http://dx.doi.org/10.1016/S0010-938X(03)00014-3
27. S. Skale, V. Dole~ek, M. Slemnik, _Corros. Sci._ 2007, _49_,
1045–1055.
http://dx.doi.org/10.1016/j.corsci.2006.06.027
28. N. A. Swartz, L.T Clare, _Electrochim. Acta._ 2012, _62_, 199–206.
http://dx.doi.org/10.1016/j.electacta.2011.12.015

Zaradi nove direktive, ki omejuje vsebnost hlapnih organskih snovi (HOS) v dekorativnih premazih, so bila razvita
alkidna veziva z visoko vsebnostjo suhe snovi. Zaradi specifi~ne kemijske strukture novih alkidnih veziv z visoko vsebnostjo suhe snovi in posledi~no spremenjenih aplikativnih lastnosti, je zelo pomembna naloga dolo~itev optimalne kombinacije in koncentracije su{ilcev v premazu. Preu~evali smo vpliv povr{inskih su{ilcev; Fe su{ilca (Fe bispidon) in Co
su{ilca (Co ethylhexanoate) v kombinaciji z globinskim Sr su{ilcem (Sr karboksilat) na su{enje in utrjevanje alkidnih
premazov z visoko vsebnostjo suhe snovi. Z infrarde~o spektroskopijo s Fourierjevo transformacijo (FT-IR) smo analizirali proces avtooksidacije. Preu~evali smo aplikativne lastnosti kot so: ~as su{enja in trdoto utrjenega premaznega filma. Z elektrokemi~no impedan~no spektroskopijo (EIS) smo po izpostavi v vla`ni komori ovrednotili kvaliteto utrjenega premaznega filma. Raziskava je pokazala, da dodatek Sr su{ilca k povr{inskima su{ilcema (Co, Fe) pospe{i avtooksidacijski proces utrjevanja. Z dodatkom vi{jih koncentracij Sr su{ilca so bili kon~ni ~asi su{enja kraj{i in vrednosti trdot premaznih filmov vi{je. Najni`ja difuzivnost ionov skozi utrjen premazni film je bila opa`ena pri kombinaciji Co/Sr
in Fe/Sr v koncentracijskem razmerju 1:1.

본문 출처 PDF: PDF 보기 · 다른 PDF는 위 [PDF 업로드]로 올릴 수 있습니다.

활용가능성

이력 0건

아직 편집 이력이 없습니다. 저장할 때마다 이전 내용이 여기에 백업됩니다.