The resin of claim 2 wherein the at least one polyol is a polyester polyol and the at least one saturated linear ether alcohol is a saturated linear ether monoalcohol containing fewer than 18 carbon atoms per molecule.
The resin of claims 1, 2, 3, 4, or 5 wherein the viscosity is below 12 poise. The resin of claims 1, 2, 3, 4, or 5 wherein the resin contains from 1. The resin of claims 1, 2, 3, 4, or 5 wherein the dibasic acid is selected from maleic acid, maleic anhydride, phthalic acid, phthalic anhydride, fumaric acid, fumaric anhydride, or mixtures thereof.
A preimpregnated unsaturated polyester resin material comprising the unsaturated polyester resin of claims 1, 2, 3, 4, or 5 and a cross-linking agent having a minimum maturation time of less than 48 hours. The process for the manufacture of an unsaturated polyester comprising condensing at least one dibasic acid or corresponding anhydride, at least one of which is unsaturated, with at least one alcohol, at least one of which is a polyol and at least one of which is a saturated linear ether alcohol containing at least one ether group, said saturated linear ether alcohol being used in an amount sufficient to provide the resin upon completion of condensation with from about 1.
The process of claim 10 wherein the at least one saturated linear ether alcohol is a monoalcohol or polyalcohol containing from 1 to 6 hydroxyl groups per molecule which is capable of esterification with an unsaturated dibasic acid.
The process of claim 10 or 11 wherein the viscosity is below 12 poise and the resin contains from 1. The process of claim 10 or 11 wherein the at least one saturated linear ether alcohol is a glycol alkoxylated by a C 2 -C 4 alkylene oxide.
The process of claim 10 wherein the at least one polyol is a polyester polyol and the at least one saturated linear ether alcohol is a monoalcohol or polyalcohol containing from 1 to 6 hydroxyl groups per molecule which is capable of esterification with an unsaturated dibasic acid.
The process of claim 10 wherein the at least one polyol and at least one saturated linear ether alcohol is a saturated linear ether polyol selected from diethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, or mixtures thereof. USA en. BEA en. CAA en. CHA5 en. DEC2 en.
DKA en. ESA1 en. FRB1 en. GBB en. ITB en. LUA1 en. Still more undesirable is the emission of poten- tially toxic compounds. There are several approaches to achieving products with low emission rates.
In the case of glass powder, aluminum hydroxide, and The earliest approach has been the use of a barium sulfate the translucency is imparted on curing suppressant which reduces the loss of volatile organic [67]. Common fillers are listed in Table 1. Fillers compounds. The suppressants are often waxes. The reduce the cost and change certain mechanical prop- wax-based products are of a limited comparability erties of the cured materials.
The wax-based suppressants separate from the system during polymerization or 1. Ca-bentonite is used in the formu- rier to volatile emissions. Waxes with a different melting point of composites. Maximum values of compressive from this temperature will not perform adequately at strength, hardness, and thermal conductivity of com- the low concentrations necessary to maintain good posites are observed at about The waxy surface layer must mum at a styrene content of Sodium montmorillonite and interlaminar adhesion bond strength of laminating organically modifiedmontmorillonite MMT were layers.
Montmorillonite inc- Suppressants selected from polyethers, polyether reases the glass transition temperatures. Unsaturated polyesters that contain the impact strength exhibited a minimum.
Instead of styrene, 2-hydroxypropyl acrylate as a 1. The functionalization of MMT can be sulfate, silica powder, glass powder, glass beads, mica, achieved with polymerizable cationic surfactants, aluminum hydroxide, cellulose yarn, silica sand, river e.
Polymerizable resin. This composite material proved to be smooth organophilic clays have been prepared by exchanging and equally distributed. No aggregation of the parti- the sodium ions of MMT with these polymeriz- cles of the marble powder was observed. With an unsaturated polyester, nanocomposites consisting of UP and clay Silica. In contrast, UP resins can be used for the were prepared.
The dispersion of organoclays in UP consolidation of marble-based natural rocks that are caused gel formation. A nanosilica filler, i. The improve- ties, such as the tensile strength, the impact strength, ment is traced back to the formation of a network the heat resistance, and the swelling resistance of between the nanosilica and the resin matrix which the hybrid, are enhanced. The properties are better results in an increased stiffness and toughness of the than those of composites prepared with pristine or cured UP composite [75].
UP, the surface of the silica particles was modified with vinyltrimethoxysilane and methacrylic acid. Fur- Rectorite. Rectorite is a layered silicate. Organi- ther the compatibility between silica and the polyester cally modified layered silicate clay composites, which resin can be improved by the addition of a block are glass fiber reinforced, are suitable to tailor the copolymer [76].
The addition of organi- cally modified rectorite increases the gel time and the viscosity [71]. Fly ash is an inexpensive material that can ers are utilized because of their low density, and their reduce the overall cost of the composite if used as relatively good mechanical properties and reactive filler for unsaturated polyester resin.
A fly ash-filled surface. The main disadvantage is the hygroscopic- resin was found to have a higher flexural modulus than ity [77] and the difficulties in achieving acceptable those of a calcium carbonate-filled polyester resin and dispersion in a polymeric matrix. Fly ash was found to have poor chem- Surface modification of these materials can help ical resistances but good saltwater, alkali, weathering, reduce these problems.
Wood flour can be chemically and freeze—thaw resistances [60]. This ral strength, and impact strength is observed when treatment decreases the hygroscopicity, but excessive the fly ash is surface-treated with silane coupling esterification has to be avoided, because it leads to the agents [72]. Fly ash-filled polymer composites The incorporation of wood flour into the resin do not show very high damping and this limits their increases the compression modulus and the yield fields of application.
However, the presence of latex stress but decreases the ultimate deformation and particles significantly enhances the damping proper- toughness in all cases.
Alkaline treatment reduces Marble. For a gray composite material, powdered the thermal stability of the wood flour and produces marble was used as filler [74].
The optimum amount a large char yield. In composites a thermal interac- of marble powder that was added was 2 g per g of UP tion between fillers and matrix is observed. They Titanium Dioxide. Titanium dioxide nanoparticles act also as low-profile additives.
A low-profile addi- with 36 nm average diameter have been investigated. The presence of the nanoparticles has a significant effect on the quasi-static fracture toughness. Even at small volume fractions an increase Toughening. Rubbers with functional groups have in toughness is observed. The changes in quasi- been tested in blends of unsaturated polyesters with static material properties in tension and compression respect to improving the mechanical properties.
The dynamic frac- ber, hydroxy-terminated natural rubber, and maleated ture toughness is higher than quasi-static fracture nitrile rubber were tested. The performance of a toughness. Quite similar experimental results have maleic anhydride grafted nitrile rubber is superior to been presented by another group [83].
Titanium diox- those of all other rubbers studied. The improvement ide nanoparticles can also be bound by chemical reac- in toughness, impact resistance, and tensile strength is tion to the polyester itself [84]. Aluminum Oxide. It was observed that the addi- Rubber as Low-profile Additive. A low-profile tion of untreated Al2 O3 particles does not result in additive consisting of a styrene butadiene rubber solu- an enhanced fracture toughness.
Instead, the frac- tion is prepared by heating styrene with hydroquinone ture toughness decreases [64,65]. This solution is taken as a low-profile ing particle dispersion process leads to a significant additive [81]. Structural composite latex particles have been For example, the addition of 4. This substance is an aluminosilicate These structural rubber particles with various shell clay mineral with the formula Al2 Si2 O5 OH 4. It structures have been used to toughen UP resins.
Halloysite is formed by the hydrother- improve considerably the impact fracture energy of mal alteration of aluminosilicates. Halloysite nano- the material. The toughening efficiency of the rubber tubes can be used as fillers in polymers, both particles is highly dependent on their content of MMA in thermoplastic polymers [85,86] and in ther- moieties [82].
For a complete list of references cf. Nanocomposite materials are increasingly commer- Therefore it has a low compatibility with hydropho- cially available but these materials are still very expen- bic polymers. Layered silicates, such as mont- sive. Table 1. Glass fibers More promising is to modify the surface of hal- Jute [93] loysite with certain coupling agents. Silane-based Sisal [94] chemicals, such as triethoxyvinylsilane and amino- Hemp [95] propyltriethoxysilane, have been proposed as cou- Wollastonite [94] Barium titanate [96] pling agents [89].
These chemicals are shown in Figure 1. The thus treated halloysite has been used as fillers in UP resins. The compositions have been characterized in several ways. It has been shown that the modifica- tion by halloysite does not result in a change of the H2N curing behavior. On the other hand, the glass transition tempera- ture of the final materials changes significantly. Therefore, expensive fibers, such as car- The addition of a nanoclay in amounts of 0. Also the gel time with unsaturated polyester resins.
If the fiber is expen- and the degree of shrinking are decreased. In the sive and has superior properties, then the matrix resin cured composites, improved thermal properties are should have superior properties.
On the other hand, the glass transition temperature is not affected. Furthermore, the impact strength is improved and a good adhesion to the sur- 1. Because of the unavoidable shrinking 1.
The growth of the nanotube surface modified. Silane coupling agents such as 3- network was shown to be dependent on the concen- methacryloxypropyl trimethoxysilane and 3-amino- tration and crossover parameters could be established propyl triethoxysilane are preferably used.
From these master curves, the rheological per- oxysilane the pendant double bonds may take part in colation was found to occur at around 0. The surface free energy and the mechanical interfa- cial properties especially showed the maximum value 1. Suitable reinforcing materials are shown in Table 1. In such a Kenaf fiber 0. The flex- Hemp fiber 1. Most synthetic resins are, however, more 1. Carbon fibers have mainly been used in Therefore, for sisal fibers naturally occurring resol- aerospace with epoxide resins or high-temperature type resins, cashew nut shell liquid is an attractive thermoplastics, whereas polyesters have found appli- alternative [].
The com- treatment of sisal fibers is done with neopentyl bination of carbon fibers and polyester matrix is diallyl oxy tri dioctyl pyrophosphatotitanate as the becoming more attractive as the cost of carbon fibers coupling agent [94,].
In comparison to epoxide resins, unsatu- forcing system for unsaturated polyester resins, the rated polyester exhibits a relatively low viscosity. This tensile strength and the flexural strength drop with property makes them well suited for the manufacture increasing sisal content. Sisal composites with unsaturated polyesters can The interfacial shear strength with untreated car- be formulated to be flame retarded using decabro- bon fibers increases with increasing degree of unsat- modiphenyloxide and antimony trioxide to reach a uration of the polyester.
The unsaturation is adjusted satisfactory high state of flame retardancy []. This is explained by a contribution of chemical bonding Kenaf Bast. Kenaf is related to jute and has sim- of the double bonds in the polymer to the functional ilar properties.
The plant occurs in southern Asia. Nowadays, Kenaf is cultivated for the sake of its fiber in southern Asia, e. The density of Kenaf fiber in comparison to other Agrowastes and biomass materials, e. These ing agents. The sodium ions in montmorillonite were fillers have very good mechanical properties and low modified to ammonium ions by ion exchange with density, and are loaded into polymeric resin matrices cetyltrimethylammonium bromide.
The composites to make useful structural composite materials [77]. Jute as reinforcing fiber is particularly signif- and fiber []. On a weight Base UP resins based on palm oil have been pre- and cost basis, bleached jute fibers are claimed to pared from the monoglyceride and maleic anhy- have better reinforcement properties than other fibers dride MA using 2-methylimidazole as catalyst. The [93]. Sisal fiber is a vegetable fiber having specific lar transesterification []. The reaction is shown in strength and stiffness that compare well with those of Figure 1.
N,N-Dimethylaminopropyl methacrylate 2-Butylaminoethyl methacrylate 2-Vinylpyridine 4-Vinylpyridine Vinylimidazole To these bio-based resins, Kenaf fibers are added as reinforcing agent. This indicates good wet- The mixture stabilizing additives should not reduce ting between the fiber and matrix [].
So, for this purpose, Sesam Husks. Sesame husks were used as rein- block copolymers based on ethylenically unsaturated forcing filler materials. The sesame husk particles monomers are added to UP resin mixtures []. Examples of monomers suitable for such additives The flexural strength, flexural modulus, and impact are shown in Table 1.
Moreover, the increase in flexural strength prop- tor. Poly propylene glycol is used as a solvent []. There are two Applications classes of mold release agents: Molding compositions based on UP resin systems are widely used in the form of []: 1.
This is costly and time consuming. For such formulations, the resins are treated with Internal mold release agents are added directly into inert fillers and with fibrous reinforcing materials. Since they do not have to When the moldings are compressed, the resin cures be continuously reapplied to the mold, internal mold by a polymerization reaction. Zinc as low-profile additives. In particular, binary copoly- stearate acts by exuding to the surface of the molding mers from methyl methacrylate and n-butyl acrylate, compound, thereby contacting the mold and provid- and ternary copolymers from methyl methacrylate, n- ing lubrication at the mold surface to permit release.
The volume fraction of microvoids phosphate esters and higher fatty acid amines []. A good vol- ume shrinkage control can be achieved by raising the 1. The surface quality is influenced mostly Dilatometric studies in the course of curing of a by dimensional changes in the process of curing. This effect both volume and morphological changes in the course results in a poor surface finish. The thermoplastics start to be effective on The shrinkage of the resin can be measured by both shrinkage control at the first transition point when the volumetric and non-volumetric methods.
Volumetric low-profile additive-rich phase and the unsaturated methods use a dilatometer design. In contrast, non- polyester resin-rich phase become co-continuous. At volumetric methods measure simply the linear amount the second transition point when the fusion among the of shrinkage. A simple method has been developed to particulate structures is severe, the shrinkage control estimate the surface finish quality of panels caused effect vanishes.
Instead of poly vinyl acetate a copolymer with of the cured products. Shrinking causes internal voids acrylic acid or itaconic acid should have better prop- and reduced surface quality. Thermoplastic resins are erties as a low-profile additive. This is based on the added to reduce shrinking, e. When the temperature is increased in the promoter, and therefore the relative reaction rate in course of curing, the styrene eventually evaporates the thermoplastic-rich and the unsaturated polyester and consequently a counter pressure is formed which resin-rich phases during polymerization.
Itaconic acid is about twice as acidic as acrylic acid The successful performance of low-profile addi- and more reactive than maleic acid or fumaric acid. Section 1. The monoester of 2-hydroxyethyl co-vinyl acetate-co-maleic anhydride have been acrylate and tetrachlorophthalic anhydride also has studied [,].
The curing rate decreases with an been proposed as a comonomer. The acidity of tetra- increase of the molecular weight of the low-profile chlorophthalic anhydride is much stronger than that of additive which causes the chain entanglement effect. Samples with an acid-modified low-profile addi- Low-profile additives with higher molecular weight tive showed an earlier volume expansion during cur- and lower content of additive seem to work better ing, as a result of faster reaction in the low-profile under low-temperature curing conditions [].
Even when added in small quantities, be controlled in addition to the selectivity control some internal mold release agents may provoke the by the low-profile additive in a reverse manner, i. Secondary monomers, such as Organically modified clay nanocomposites have divinylbenzene and trimethylol propane trimethacry- been tested as low-profile additives []. The shrink- late, were added to the formulation. On the other hand, 2,4-pentandione increased the reaction rate in the low- some other mechanical properties are improved sig- profile rich phase.
Methyl methacrylate was tested as a secondary monomer []. At a low ratio of methyl methacry- 1. However, at a high ratio of An interpenetrating polymer network is a mixture methyl methacrylate to styrene, the amount of residual of two or more polymers that are not necessarily styrene can be substantially reduced.
This advanta- independently crosslinked. If another polymer that is geous behavior occurs because of the monomer reac- capable of crosslinking separately is added to an tivity ratios. However, the study of shrinkage shows unsaturated polyester resin, the physical properties that methyl methacrylate has a negative effect on the can be enhanced dramatically. Other special types of shrinkage control.
There- 1. The performance of compounds that simultaneously form a crosslinkable a low-profile additive becomes less effective when poly urethane are added, such as polyglycols and the molar ratio of methyl methacrylate to styrene diisocyanates []. The rate of reaction of one component might be A dual initiator system, i. However, during free- in combination with cobalt octoate as promoter.
When the poly- the proper progress of the reaction. On the other merizing bulk becomes more viscous as the concen- hand, tert-butylperoxybenzoate is more active com- tration of polymer increases, the mutual deactivation pared to methylethylketone peroxide at high tem- of the growing radicals is hindered, whereas the other peratures, because the latter completely decomposes.
For an unsaturated polyester resin-poly urethane Volume shrinkage measurements of the resin sys- system, the rate of the curing process increased sub- tem initiated with dual initiators revealed that a good stantially in comparison to the pure homopolymers.
Moisture, which does not influence the curing cumene hydroperoxide and tetrahydrophthalic anhy- reaction of the unsaturated polyester resin, would also dride, or BPO and tetrahydrophthalic anhydride []. The incorporation of bis- ponents, acrylonitrile, and an unsaturated polyester maleimide into epoxy resin improved both mechani- resin the main component was synthesized in order cal strength and thermal behavior of the epoxy resin. By incor- porating the urethane and acrylonitrile structures, the 1.
The introduction of vinylester Maleated castor oil has been used as a biomodifier oligomer and bismaleimide into an unsaturated in composites from UP resins and fly ash []. The polyester resin improves thermomechanical proper- maleated castor oil is polymerized and crosslinked ties []. For this reason, an IPN is formed. This causes a significant enhancement in the properties. The addi- 1. Also, resin not only improves heat resistance but also helps the glass transition temperature shifts to a higher to suppress the smoke, toxic gas, and heat release dur- temperature.
Since a single glass transition temperature for prepared using an unsaturated polyester and sil- each interpenetrating polymer network is observed, it ica gel. First an unsaturated polyester is prepared. On To this polyester the silica gel precursor is added, the other hand, an interlock between the two grow- i. A network interlock is indicated by a lower total using HCl catalyst in the presence of the unsaturated exothermic reaction during simultaneous polymeriza- polyester resin.
It was confirmed by nuclear mag- tion in comparison to the reaction of the homopoly- netic resonance spectroscopy that the polyester did mers []. Finally, the inter- The thermal and dynamic mechanical properties of penetrating network was formed by photopolymer- interpenetrating networks formed from unsaturated ization of the unsaturated polyester resin []. It is polyester resin and epoxy resins were investigated.
It was shown that both the content of epoxy resin and the curing system influence the properties. The polyester is prepared with an excess of diol and UV Absorbers Type Manufacturer diluted with styrene as usual.
Suitable peroxides Fumed silica Inorganic are added to initiate the radical curing. The curing starts with the reaction between the iso- cyanates and the hydroxyl groups, thus forming the poly urethane linkage. Then the crosslinking reac- tion takes place [].
The mechanical properties of the hybrid networks Table 1. Hybrid networks with Melamine cyanurate [] EG as the chain extender are stiffer. Ammonium polyphosphate [] Nanoclays [] 1. The UV stability is improved by the addition of light stabilizers and UV absorbers.
A special class of light stabilizers are hindered amine light stabilizers HALS. These stabilizers oxidize and scavenge rad- components, and by flame retardant vinyl monomers. On the other Halogenated compounds are still common, but there hand, UV absorbers shield the polymer by absorbing is a trend toward substituting these compounds with UV and dissipating the energy as heat.
Combinations halogen-free compositions. In halogenated systems, of these classes of compounds can be readily used. On the other hand, a disposal used as additives are summarized in Table 1. Flame retardants are summarized in 1. The major drawback of UP resins is their flamma- In general, bromine compounds are more effec- bility.
For example, a general grade UP made with tive than chlorine compounds. Antimony trioxide is synergistic to halo- Flame retardant compositions can be achieved by genated flame retardants. It acts also as a smoke flame retardant additives, by flame retardant polyester suppressant in various systems []. Some improvement of the mechanical properties can be achieved by adding acrylonitrile to the polyester [].
Decabromodiphenyloxide with Figure 1. Aluminum Hydroxide. Fillers, such as aluminum hydroxide, yield crystallization water at higher tem- effect of the polyacrylates is also effective in those peratures, thus achieving a certain flame retardancy.
Preferred polyacrylates are those parts of aluminum hydroxide per parts of having backbones of a type that is known to contribute unsaturated polyester resin, it is possible to achieve to char formation, for example those having alkylene self-extinguishing and a low smoke density.
A disad- or oxyalkylene backbones []. The density can be reduced if hollow Reactive Phosphor Compound. Oxaphospho- filler is used for reinforcement []. Certain derivatives Lower amounts of aluminum hydroxide are suffi- are reactive to alcohols and can be incorporated in a cient if red phosphorus and melamine or melamine polyester backbone. Due to their phosphor content cyanurate are admixed [].
Magnesium hydroxide they also act as flame retardants, with the advantage acts in a similar way to aluminum hydroxide. The ring opening reaction of 2-methyl-2,5-dioxo Ammonium Polyphosphate. Ammonium poly- oxaphospholane is shown in Figure 1.
As a side phosphate is a halogen-free flame retardant for unsat- effect, phosphoric compounds increase the adhesion urated polyester resin composites []. Commonly of the final products, without toughening too much. This compound melamine salts, e.
The The effect of aluminum trihydroxide in combina- synthesis is shown in Figure 1. Thermogravimetric experiments revealed an ied by thermogravimetric analysis both in air and in improved thermal stability in the range of — nitrogen [].
The fire retardant polyacrylate component should Expandable Graphite. The flammability of cross be distinguished from the unsaturated monomers that linked unsaturated polyester resins is reduced by the may be included as crosslinkers in the resin systems. It addition of EG even at levels as low as 7 phr. Expand- cannot be ruled out that the polyacrylate may become able graphite is particularly useful when used in com- involved in the crosslinking reactions of such systems.
The bromine content decreases the flamma- CH 2 bility of the final products. The resins can be photocured in a system con- sisting of mono- or diazide and hydroxy alkylphenone []. Flame retardant polyester resin polymers wherein the ability of the polyester resin to transmit light is not significantly affected can be formulated using, O P O instead of antimony trioxide, organic antimony CH 2 compounds together with halogen flame retardants.
Antimony ethylene glycoxide i. Antimony tri-alloxide and antimony hydroxycarbonyl propyl]phosphaphenanthrene- methacrylate are vinyl monomers [].
The anti- oxide []. Polymer-layered silicate nanoclays corresponding alcohol in an inert solvent, e. The antimony acylates are prepared by mix- While the incorporation of condensed-phase ing stoichiometric amounts of saturated or unsaturated flame retardants, such as ammonium polyphosphate, acid and antimony alkoxide.
The best results formulations using antimony trioxide is sufficient to are observed with ammonium polyphosphate and retain the self-extinguishing properties. Examples are HET acid, tetrachlorophthalic anhydride, and tetra- 1. The mechanical properties decrease with increasing halogen content in the back- Curing is achieved in general with a radical initiator bone [].
HET acid is used for fireproof applica- and a promoter. A promoter assists the decomposition tions, e. Promoters are also addressed as Monomers accelerators. Dibromostyrene is a suitable brominated vinyl monomer []. However, it is not commonly used. Coatings of unsaturated polyester resins are Both monomers act effectively against inhibition by cured with light-sensitive materials. Functional perox- Monomer Mill. Year Reference ides based on pyromellitic dianhydride, PEG, and tert- Metric butyl hydroperoxide contain two types of functional Tons groups: Methyl methacrylate 2 [] Styrene 21 [] Phthalic anhydride 3.
Carboxylic groups that can participate in ionic Isophthalic acid 0. Peroxide groups that can initiate certain radical Adipic acid 2 [] reactions. Bisphenol A 2 [] Maleic anhydride 1. Unsaturated polyester resins 1. Some common photoinitiators are listed in Table 1.
A common problem is yellowing dur- Peroxide Type Example ing curing. Such derivatives are Acetyl acetone peroxide used in thin layers. Hydroperoxides Cumene hydroperoxide Diacyl peroxides Dibenzoyl peroxide Although suitable initiators for clear systems have Dialkyl peroxides Dicumyl peroxide become available only in the last few years, photoini- tert-Butylcumyl peroxide tiators for pigmented systems have been developed Alkyl peresters tert-Butylperoxyethylhexanoate for some time.
Problems with regard to the absorb- tert-Butylperoxybenzoate tion of ultraviolet light, needed for curing, arise when tert-Amylperoxybenzoate the coating is pigmented or when it is UV stabilized tert-Hexylperoxybenzoate Percarbonates Bis 4-tert-butylcyclohexyl - for outdoor applications. Ultraviolet stabilizers con- peroxydicarbonate sist of ultraviolet absorbers or hindered amine light stabilizers.
In a 2-liter 4-necked flask equipped with a thermometer. While nitrogen gas was passed through the flask. When a methanol tolerance reached 2. To the reaction product of stage A were added parts of maleic anhydride. The mixture was heated to C to effect reaction. The progress of the reaction was checked by measurement of the acid number and viscosity of the reaction mixture.
The reaction product of stage B was dissolved in parts of styrene to produce a light yellow, transpar ent unsaturated polyester resin with the characteristic properties as shown in Table l.
The effect of using hydroquinone alone or pbenzoquinone alone in lieu of a combination of hydroquinone and triphenyl phosphite at stage A in this ex ample is also shown in Table l as Experiment 2 or 3. In the case of Experiment 2. In the case of Experiment 3. Table l hxperimem l 2 3 Starting Dimcthyl tcrcphthalatc Additional Malcic anhydride 0 Acld number 9.
Although the and finished at the time when the methanol tolerance viscosity was increased and white turbidity appeared. To the reaction product of stage A were added on storage. At the time the acid number of the reaction mixture became A. The reaction product of stage B was dissolved in nol tolerance of 2. To the reaction product of stage A were added properties shown in Table 2. The reacsingly in place ofthc combination of hydroquinone and tion was carried out according to the procedure detriphenyl phosphite used at the A stage of this example.
When the acid number of the re- Howevensatisfactory results were not obtained in all of action mixture became l7 and the viscosity of a soluthe cases. For example, when using 2,5-dition containing styrene reached 2. The reaction product of stage B was dissolved in took place during the B stage reaction.
When using 2. Moreproperties shown in Table 3. This resin was lightly colover, the product was obtained in virtual gelled state ored but its stability on storage was good. The were repeated. Moreover, the automotive industry is employing UPRs to produce high-performance components, including fenders, closure and body panels on cars, bumpers, off-highway bonnets, etc.
This, in turn, is anticipated to bolster the market growth in the coming years. In case you need any specific business requirements, you can mention the same. We can customize the report based on the specific needs of the client. Note: As the novel coronavirus COVID crisis takes over the world, we are continuously tracking the changes in the markets, as well as the industry behaviors of the consumers globally, and our estimates about the latest market trends and forecasts, are being done after considering the impact of this pandemic.
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