Isophthalic resins

Norsodyne Resin, Isophthalic type (high resistance to hydrolysis and organic solvents) acid index, 13 styrene content, 50 wt % viscosity (Brookfield-type rotational viscometer) at 25 °C, 160 mPa s (cP) and volumetric shrinkage, 9%. 

Adipic acid dimethyi adipate (polyesters), acrylamide (acrylonitrile co-polymers), acrylonitrile (acrylamide co-polymers), acrylic acid (acrylic polymers), buta-1,3-dlene (PS co-polymers, elastomers), butan-1,4-diol (polyesters), 2,2-bis(4-hydroxyphenyl)butan-1-ol (polyesters), 1,1-bis(4-hydroxyphenyl)cyclohexane (polyesters), 4,4 -(propane-2,2-diyl)-dlphenol known as bisphenol A (polyesters), ethyleneglycol (polyestere), formaldehyde (phenol-formaldehyde resins), isophthalic acid (PET), caprolactame and C -C,2 aminocar-boxyllc acids and their lactames (polyamides), melamine (amino-formaldehyde resins), methacryllc acid and methyl methacrylate (acrylic polymers), methylstyrene (PS and co-polymers), propyleneglycol (polyesters), sebacic acid and dimethyl sebacate (polyesters), styrene (PS and co-polymers), terephthalic acid and dimethyl terephthalate (PET), vinyl acetate (vinyl acetate co-polymers), vinyl chloride (PVC and co-polymers), vinylldenechlorlde (PVdC and co-polymers)... 

Although phthalic anhydride is the most common dibasic acid for producing alkyd resins, isophthalic acid, terephthalic acid, trimellitic anhydride and maleic anhydride are also used. Isophthalic and terephthalic acid are often used in exterior coatings where improved hydrolitic stability is required. Maleic anhydride is used with other polybasic acids as a modifier to increase viscosity and film hardness. Trimellitic anhydride is used in making water soluble alkyds for specific applications. 

Some time earlier, Eastman-Kodak has been working on a novel polyester as an entry into the important polyester fiber market and had devised a new ahcychc diol, 1,4-cydohexanedimethanol [105-08-5] effectively made by exhaustive hydrogenation of dimethyl terephthalate. Reaction of the new diol with dimethyl terephthalate gave a crystalline polyester with a higher melting point than PET and it was introduced in the United States in 1954 as a new polyester fiber under the trade name Kodel (5). Much later the same polyester, now called PCT, and a cyclohexanedimethanol—terephthalate/isophthalate copolymer were introduced as mol ding resins and thermoforming materials (6). More recentiy stiU, copolymers of PET with CHDM units have been introduced for blow molded bottie resins (7). 

Fig. 7. Influence of copper naphthenate on exotherm temperature. Composition in pph isophthalic laminating resin is cobalt naphthenate (0.20), dimethylaniline (0.05), and copper naphthenate, A (0.00) B (0.01) C (0.015) orD (0.02).

Table 8. Strength Characteristics of Isophthalic Resin and Composite Derivatives...

Most polyesters (qv) are based on phthalates. They are referred to as aromatic-aHphatic or aromatic according to the copolymerized diol. Thus poly(ethylene terephthalate) [25038-59-9] (PET), poly(butyelene terephthalate) [24968-12-5] (PBT), and related polymers are termed aromatic-aHphatic polyester resins, whereas poly(bisphenol A phthalate)s are called aromatic polyester resins or polyarylates PET and PBT resins are the largest volume aromatic-aHphatic products. Other aromatic-aHphatic polyesters (65) include Eastman Kodak s Kodar resin, which is a PET resin modified with isophthalate and dimethylolcyclohexane. Polyarylate resins are lower volume specialty resins for high temperature (HDT) end uses (see HeaT-RESISTANT POLYAffiRS). 

A convenient method of compositional designation uses molar percentages of ester and carbonate linkages coupled with the molar percentages of iso- and terephthalate units in the polymer. A 70% ester, 30% carbonate polyester carbonate with 60 parts of isophthalate and 40 parts of terephthalate is designated 70(60/40)30. Similarly, a standard PC resin is 0(0/0)100, and a polyarjlate resin composed of a 1 1 molar ratio of iso- to terephthalate units esterfied with bisphenol A is designated 100(50/50)0. 

Isophthalic acid (m.p. 347°C), made by oxidation of /w-xylene, has also been introduced for resins. The resins have higher heat distortion temperatures and flexural moduli and better craze resistance. They are also useful in the preparation of resilient gel coats. 

Systems based on isophthalic acid often show better water and alkali resistance than those based on phthalic anhydride. This is not thought to be due to inherent differences between the phthalic and isophthalic structures but is ascribed to the fact that isophthalate resins have generally considerably higher viscosities which enable them to be diluted with greater amounts of styrene. It is the additional proportion of styrene which gives the improved water and alkali resistance. 

This monomer has been used as the basis of a laminating resin and as a reactive diluent in polyester laminating resins, but at the present time its principal value is in moulding compositions. It is possible to heat the monomer under carefully controlled conditions to give a soluble and stable partial polymer in the form of a white powder. The powder may then be blended with fillers, peroxide catalysts and other ingredients in the same manner as the polyester alkyds to form a moulding powder. Similar materials may be obtained from diallyl isophthalate. 

Maximum chemical resistance of polyester mortars is obtained from cements made from isophthalic or biphenol resins. The biphenolic resins are preferred for alkaline and hypochlorite solutions. 

Processes have been developed separating pure metaxylene from other Cj aromatics.Metaxylene is a raw material for the manufacture of isophthalic acid. The major outlets for the acid are in the synthesis of unsaturated polyester and alkyd resins, and for the production of isophthalic esters (plasticizers). 

In the characterization of alkyd resin formulations the palmitic acid to stearic acid (P/S) ratio, often used to identify the type of oil in a binder, cannot be applied as many different oils other than the traditional ones are commonly employed in industrial formulations. Moreover, they are often in mixtures, with the additional complication that fatty acids are also sometime added to the vegetable oils, thus making it impossible to rely on measured P/S values. In any case it is important to always derivatize the samples if Py-GC/MS is used and an alkyd is suspected. Phthalic anhydride will be detected also in an underivatized alkyd pyrogram however, isophthalic acid will not, leading to confusion and the possibility of uncorrected identification [92]. 

Isophthalic (m-phthalic) acid (IPA) 10 216, 20 96, 102-103 Isophthalic resin(s), 20 114 formulation of, 20 102-103 mechanical properties of, 20 111-112 strength characteristics of, 20 112t Isophthalonitrile, 17 245 Isophthaloyl chloride, polymers derived from, 23 730... 

Thermosensitive hydrogels, 13 743 THERMOSET Thermoset recycling pyramid, 13 780-781 Thermoset elastomers, 20 71 Thermoset epoxy resins, curing of, 10 421 Thermoset flexible polyurethane foams properties of, 25 461 Thermoset matrix composites, 21 456 Thermo set molding properties of diallyl isophthalate, 2 262t Thermoset polymers, 25 455 cured, 10 425... 

The isophthalic acid, maleic anhydride and glycol resins. These are generally referred to as isophthalic resins , or simply iso resins . 

This problem was solved by the introduction of a new improved resin. This major innovation in the UPR industry came after the introduction of isophthalic acid, and especially the pioneer work of its incorporation into UPRs by the Amoco Chemical group. This very significant and extremely logic development led to the so-called high-performance resins. 

The blending of DCPD resins has become an important practice. Typical blended resins include combinations of DCPD resins with isophthalic, orthoph-thalic or vinyl ester resins. Creating blends with higher-molecular-weight phthalic anhydride, isophthalic or vinyl ester resins can toughen neat DCPD resins, which are inherently brittle. In the case of vinyl ester and isophthalic and DCPD blends, a degree of improved chemical resistance and hydrolytic stability can be gained. 

Table 21.2 provides a general guide to the effect that chemical constituents can have on unsaturated polyester resin end-use performance. The routes to change an unsaturated polyester resin for a particular application is normally apparent and there can be several pathways available to achieve the desired properties. As the unsaturated polyester resin markets are highly competitive, raw material cost usually reduces the number of available routes available to the formulator. As noted previously, there are three main types or families of unsaturated polyesters, namely general purpose orthophthalic, isophthalic and DCPD resins. However, within each of these families, there are hundreds of variants that incorporate these various chemical constituents in different combinations and permutations to achieve the desired results. 

Tooling/molds anhydride resin blends Isophthalic... 

The unsaturated polyester resins used to produce gel-coat formulations can be classified into three categories, i.e. orthophthalic-, isophthalic- and neopentyl-glycol-based. The first two types are used in perhaps two thirds of all... 

Unsaturated polyesters are generally very brittle materials. The tensile elongation for most UPRs is in the range of 1 % for dicyclopentadiene (DCPD)-based polyester resin to about 2.5 % for isophthalic acid and propylene glycol resins. This 1 % elongation posts a problem for using DCPD resin in making a... 

Isophthalic acid is made by the same process as TPA, liquid phase air oxidation. Yields are about 80%. Isophthalic does have some unique redeeming value—it will enhance, to some extent, the mechanical and temperature sensitive properties of polyesters, alkyd resins, and glass reinforced plastics. 

Uses Preparation of phthalic acid, phthalic anhydride, terephthalic acid, isophthalic acid solvent for alkyd resins, lacquers, enamels, rubber cements manufacture of dyes, pharmaceuticals, and insecticides motor fuels. 

---