Acrylic formula design is fully summarized

First, acrylic definition
: acrylic, methyl acrylates and styrene and other vinyl monomers as the main raw material synthesis of co-polymer called acrylic resin.
II, acrylic resin classification
1, according to the composition of the composition: propylene resin, phenyl resin, silicone propylene resin, acetate resin, fluorine resin, acrylic (schocarbonate-acrylic) resin and so on.
2, according to film-forming properties: thermoplastic acrylic resin and thermooensolated acrylic resin

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thermoplastic acrylic resin its film-forming mainly by solvent or dispersion medium (often water) volatile so that large molecules or large-molecule particles gathered into the film, film-forming process did not occur chemical reactions, the disadvantage is that the film resistance is poor solvent resistance;
thermocure acrylic resin is also known as reactive crosslinking resin, its film-forming process is accompanied by several parts of the reaction group cross-linking reaction, so the coating film has a mesh structure, so its solvent resistance, good chemical resistance, suitable for the preparation of anti-corrosion coatings.
, acrylic monosome
according to the effect of monosome on coating film performance is often classified as follows, to facilitate application.
single body name
function
methyl acrylates
methyl acrylates
styrene
propylene eye
improve hardness,
called hard monosome.
acetylene
acrylates
acrylic laurel
acrylic-2-ethyl hetamine
methyl acrylic laurel
methyl acrylates
improve flexibility, promote film,
called soft monosome.
acrylic-2-hydroxyethyl ethyl
acrylic-2-hydroxypropylate
methyl acrylic-2-hydroxyethyl
methyl acrylic-2-Hydroxypropyl
methyl acrylic shrinkage glycerides
acrylamide
N-hydroxymethylamide
N-butymethyl (meth) acrylamide
Diacetone acrylamide (DAAM)
methyl acrylic acetate (AAEM)
defyl benzene
vinyl trimethyl silane
vinyl triethyl Oxygen-based silane
vinyl trioxysilane
γ-methyl acrylamide propylene
introduced into the official energy group or cross-linking point,
increase adhesion,
called a cross-linking monosome.
alkylate
styrene
anti-pollution
methyl acrylates
styrene
methyl acrylic laurel
acrylic -2-ethyl hethyl
water resistance
acrylic
methyl acrylates
methyl acrylic laurel
solvent resistance
acrylates
Orthobutyl acrylic
acrylic-2-ethyl hetamine
methyl acrylates
methyl acrylates
-closed, color-protected
acrylic
methyl acrylic

methyl butyric acid
styrene sulfonate
Sodium vinyl sulfonate
AMPS
achieves water solubility and increases adhesion, which
calls water-soluble monosomes and
surfactant monosomes.
4, acrylic co-polymerization
1, co-polymer purpose: (1) improve the resin Tg (2) regulation of resin polarity, solubility, mechanical and mechanical properties, such as acrylic, methyl acrylic can improve the adhesion of paint film and substrate; The reactant reacts to form a cross-linked structure, the main functional monomers are: acrylic hydroxyethyl (hydroxypropylate), N-hydroxymethyl acrylamide, the introduction of -OH acrylic acid, methyl acrylic acid, the introduction of -COOH to make the co-polymer water-soluble, improve resin adhesion, and related crosslinker reaction. Therefore, according to the use of coating requirements, choose the appropriate monomer for co-polymer molecular design and through experiments, the development of resin to meet the requirements of the coating resin so that our research and development personnel pursue the goal.
2, co-polypric Tg calculation formula:
5, acrylic formula design principles
acrylic resin and its coating applications are very wide, so its formulation design is very complex. The basic principles mainly follow the following points:
1, for different substrates and products to determine the resin dosage form - solvent type or water dosage form;
2, according to performance requirements to determine the composition of the monoid, glass temperature (Tg), solvent composition, trigger type and dosage and polymerization process;
finally through experiments to test, correct, to determine the best product process and formulation. The choice of monosome is the core content of formula design.
6, the choice of monosome
1, monogam overview
for easy application, usually the aggregate monosome is divided into hard monosome, soft monosome and functional monosome three categories, specifically can refer to the table above.
methyl acrylates (MMA), styrene (ST), acrylic (AN) are the most commonly used hard monogs;
ethyl acrylates (EAs), acrylates (BA), acrylic isoenesters (2-EHA) are the most commonly used soft monogbodies.
long chain of acrylic and methyl acrylates (e.g. laurel, octane) have better alcohol and water resistance.
functional monogies are hydroxy acrylates and methyl acrylics, and the monoglycerides containing pyrethroids are acrylic and methyl acrylic. The introduction of hydroxyl can provide solvent-based resins with polyurethane curing agent, amino resin cross-linking the official energy group.
other functional monoliths are: acrylamide (AAM), hydroxymethyl acrylamide (NMA), diacetone acrylamide (DAAM) and acetylate (AAEM), methyl acrylic shrinkage glyceride (GMA), methamphetamine (DMA) and so on.
the amount of functional monosome is generally controlled at 1% to 6% mass, not too much, otherwise it may affect the storage stability of resin or paint. For more information on monosome selection, see: Summary of monosome selection principles during acrylic synthesis.
vinyl isopropyloxylsilane monosomyne due to isopropyl bit resistance effect, Si-O bond hydrolysing is slow, in the emulsion polymerization of its dosing can be increased to 10%, is conducive to improving the water resistance of emulsion, weather resistance and other properties, but its price is higher.
The introduction of niobine-based monosomes can improve the retouching and adhesion of resins to pigments, fillers and substrates, and are reactive to epoxy groups and catalytic to the curing of amino resins.
2, hydroxypropyl acrylic resin
when synthetic hydroxypropyl acrylic resin, the type and dosing of hydroxyl monoxyl has an important impact on resin performance.
hydroxypropylates of a two β-part polyurethane system are commonly used in hydroxypropyl monomers
: acrylic hydroxyethylate (HEA) or methyl acrylates β (HEMA); The high activity of the hydroxyl monolith is high, and when the hydroxypypyl composition of the ammonia-baked resin is used, the hydroxyl propylene monoglyceride can be selected.
In addition, hydroxy-type chain transfer agents (e.g. -based ethanol, -based propylene alcohol, -based propylene acid-2-hydroxyethylate) can be introduced at the polymer chain end, improving hydroxyl distribution, increasing hardness, and narrowing the molecular weight distribution, reducing the viscosity of the system.
3, other precautions
In order to improve ethanol resistance, we should introduce styrene, acrylic and methyl acrylic advanced alkyl esters to reduce the ester content. Both can be considered to balance weather and ethanol resistance. Methyl acrylic advanced alkyl esters have methyl acrylic laurel, methyl acrylic 18 alcohol esters and so on.
resins used in coatings are often co-polymers, and their co-polymer activity must be taken into account when selecting monomers. In practice, the composition of the copolymer is controlled by the "hungry state" feeding method of the monomer mixture (i.e., the single-body feeding rate also pay attention to the toxicity of the monoglyceride, the toxicity of acrylic in general is greater than the toxicity of the corresponding methyl acrylates, such as the toxicity of acrylates is greater than the toxicity of methyl acrylates, in addition to the toxicity of ethyl acrylates is also greater. In monomers used with acrylic monomers, acrylic eyes and acrylamide are highly toxic and should be protected.
, Tg design
glass temperature reflects the transformation of untype polymers from brittle glass to high-bounce temperature. The glassing temperature of the resin varies greatly from one coating to the other. The elastic emulsion used in exterior paint is generally lower than -10 degrees C, which should be lower in the north, while the resin used in the thermoplastic paint is generally higher than 60 degrees C. Crosslinked acrylic resins are generally at -20 to 400 degrees C. Glassing temperature design is commonly used FOX formula:
where, for the ith kind of monomer mass fraction, for the ith kind of monomer corresponding to the glass temperature of the oxide, in K. The glassed temperature of some monosomes can be checked.
the formula calculation value has some reference value, but its accuracy is related to the composition of the monosome, and it is not certain.
, the choice of
solvent-based acrylic resin, the trigger mainly has oxygen and acetone two kinds.
commonly used peroxygen triggers trigger activity can be seen in the table below:
wherein benzoyl peroxide (BPO) is one of the most commonly used peroxygen triggers, normal use temperature of 70 to 100 degrees C, peroxide triggers easy to induce decomposition reaction, and its primary free agent easy to seize hydrogen, chlorine and other atoms or groups in the large molecular chain, and then the introduction of a branch chain in the large molecular chain, so that the molecular distribution width. In recent years, benzoyl peroxide is an important application of the trigger, micro-yellow liquid, boiling point 124 degrees C, dissolved in most organic solvents, room temperature stability, insensitive to impact, convenient storage and transportation, it overcomes some shortcomings of peroxylic triggers, the synthetic resin molecular weight distribution is narrow, conducive to the improvement of solid composition.
varieties of acetylene triggers are few, and the main commonly used are acetylene (AIBN) and acetylene (ABVN). Among them, AIBN is the most commonly used variety of triggers, using a temperature of 60 to 80 degrees C, the trigger generally does not induce decomposition reaction, the resulting large molecule molecular weight distribution is narrow. Thermoplastic acrylic resins are often used as such triggers. Its trigger activity can be seen in the table below:
In order to make the polymerization smooth, solution polymerization often uses the process of mixing drops with monosomes, monogam drops are added, after a few hours of insulation, also need one or several additional drops to eliminate the trigger, in order to maximize the conversion rate, each trigger dosage of 10%-30% of the former.
9, solvent selection
used as a room temperature curing two-component polyurethane hydroxyl components of acrylic resin can not use alcohol, ether alcohol solvents, in order to prevent its reaction with isocyanate group, the water content of the solvent should be as low as possible, can be after polymerization, decompression out of part of the solvent, in order to bring out a small amount of water system. Commonly used solvents for toluene, xylene, can be appropriately added ethyl acetate, butyl acetate. Environmental protection paint solvents are not allowed to contain "tribenzene" - benzene, toluene, xylene, usually ethyl acetate, butyl acetate (BAC), propylene glycol methyl ether acetate (PMA) mixed solvents. There are also systems that use butyl acetate and heavy aromatics (e.g. heavy aromatic S-100, heavy aromatic s-150) as solvents.
acrylic resin with hydroxypropyl acrylic resin can be used as a mixture of xylene, butanol, sometimes spelled into some butyl soluble fiber (BCS, glycol butyl ether), S-100, PMA, ethylene glycol ether ethylate (CAC).
in addition to the above solvents, acetone, butyl (MEK), methyl isobutyl ketone (MIBK) and other ketone solvents, ethanol, isopropyl alcohol (IPA), butanol and other alcohol solvents can also be used.
In fact, resin use determines the composition of the unit and solvent selection, in order to make the polymer temperature system in the reflow state, solvent commonly used mixed solvents, low boiling point components reflow action, once the reflow solvent is determined, you can choose the trigger according to the reflow temperature, the solution polymerization, the main trigger at the polymerization temperature of the half-life is generally better between 0.5 and 2h. Sometimes a lower active trigger can be used in a compound, and its half-life is usually between 2 and 4h.
, molecular weight regulator
in order to regulate molecular weight, it is necessary to add molecular weight regulator (or viscosity regulator, chain transfer agent). Molecular weight regulators can be long-chain free-agents to seize atoms or groups, long-chain free-agents into a dead large molecule, and regenerate a free-agent with triggering, growth activity, so good molecular weight regulators only reduce polymerization or molecular weight, no effect on polymerization rate. Its dosage can be calculated using the average polymerization equation, but the polymer dynamics parameters of free-based polymerization are difficult to find, and even the chain transfer constant of the same regulator is a variable of the polymerization condition, so its dosage can only be determined by multiple sets of experiments. The most commonly used variety is thiol compounds. Such as positive twelve alkyl thiol, zhong twelve alkyl thiol, uncle twelve alkyl thiol, ethanol, acetic acid and so on. ethanol can be introduced into the polymer chain when transferred and then triggered, reducing the amount of hydroxyl monosome used in hydroxypropyl acrylic synthesis.
thiol generally has a bad smell, its residue will affect the sensory evaluation, so its dosage should be well controlled, at present, there are some low odor transfer agents to choose from, such as methyl styrene diamer. In addition, according to the principle of polymerization control, by increasing the amount of trigger can also play a certain regulatory role in molecular weight.
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