Phosphites, stabilizer for

Tris nonylphenyl phosphite is one of the oldest and most often used phosphite stabilizers for polymeric materials. In liquid form, it is economical to use even at over twice the loading of alternative dry phosphites, and its hquid form has advantages in handling and metering. It is used in LLDPE bags and food packaging and HOPE blow-molded dmms and box wrapping film [3-5, 3-6]. 

Cost bilizers. In most cases the alkyl tin stabilizets ate particularly efficient heat stabilizers for PVC without the addition of costabilizers. Many of the traditional coadditives, such as antioxidants, epoxy compounds, and phosphites, used with the mixed metal stabilizer systems, afford only minimal benefits when used with the alkyl tin mercaptides. Mercaptans are quite effective costabilizets for some of the alkyl tin mercaptides, particularly those based on mercaptoethyl ester technology (23). Combinations of mercaptan and alkyl tin mercaptide ate currendy the most efficient stabilizers for PVC extmsion processes. The level of tin metal in the stabilizer composition can be reduced by up to 50% while maintaining equivalent performance. Figure 2 shows the two-roU mill performance of some methyl tin stabilizers in a PVC pipe formulation as a function of the tin content and the mercaptide groups at 200°C. 

The basic metal salts and soaps tend to be less cosdy than the alkyl tin stabilizers for example, in the United States, the market price in 1993 for calcium stearate was about 1.30— 1.60, zinc stearate was 1.70— 2.00, and barium stearate was 2.40— 2.80/kg. Not all of the coadditives are necessary in every PVC compound. Typically, commercial mixed metal stabilizers contain most of the necessary coadditives and usually an epoxy compound and a phosphite are the only additional products that may be added by the processor. The requited costabilizers, however, significantly add to the stabilization costs. Typical phosphites, used in most flexible PVC formulations, are sold for 4.00— 7.50/kg. Typical antioxidants are bisphenol A, selling at 2.00/kg Nnonylphenol at 1.25/kg and BHT at 3.50/kg, respectively. Pricing for ESO is about 2.00— 2.50/kg. Polyols, such as pentaerythritol, used with the barium—cadmium systems, sells at 2.00, whereas the derivative dipentaerythritol costs over three times as much. The P-diketones and specialized dihydropyridines, which are powerful costabilizers for calcium—zinc and barium—zinc systems, are very cosdy. These additives are 10.00 and 20.00/kg, respectively, contributing significantly to the overall stabilizer costs. Hydrotalcites are sold for about 5.00— 7.00/kg. 

Phosphite esters are frequently employed as peroxide decomposers they act by reducing hydroperoxides to alcohols (equation 5). The phosphite esters can be used in combination with phenolic antioxidants when synergism may be observed. They are important stabilizers for polyenes, rubbers and poly(vinyl chloride). Among compounds known to be active are the cyclic esters (5) and (6) (B-80MI11503). 

A number of ortho hindered alkyl-substituted phenyl phosphites and phosphonites were found to be effective process stabilizers for polypropylene and high density polyethylene combining more effective stabilization activity at high temperatures with good storage stability at relatively elevated humidity and ambient temperature, as well as resistance to discoloration. 

The mechanism of stabilisation of PVC by calcium/zinc stabilisers is briefly discussed and the development of highly efficient, solid and liquid calcium/zinc stabilisers based on novel types of calcium, zinc, calcium-zinc or calcium-zinc-phosphite intermediates for PVC is reported. These new stabilisers are capable of providing PVC compounds having equivalent or improved static heat stability when compared with commercial barium-zinc stabilisers even without the addition of high cost costabilisers. Data in graph form on PVC compounds containing these stabilisers are included. 33 refs. 

Other Plastics Uses. The plasticizer range alcohols have a number of other uses in plastics liexanol and 2-ethylliexanol are used as part of the catalyst system in the polymerization of acrylates, ethylene, and propylene (55) the peroxydicarbonate of 2-ethylliexanol is utilized as a polymerization initiator for vinyl chloride various trialkyl phosphites find usage as heat and light stabilizers for plastics organotin derivatives are used as heat stabilizers for PVC octanol improves the compatibility of calcium carbonate filler in various plastics 2-ethylliexanol is used to make expanded polystyrene beads (56) and acrylate esters serve as pressure sensitive adhesives. 

Phosphorous acid, H3PO3, is generated by hydrolysis of PCI3 - industrially this is carried out by spraying the chloride into steam at 190 °C. Esters of the acid, both the triaUcyl esters [P(OR)3] and the diaUcyl esters [(RO)2P(0)H], can be produced directly by substituting the appropriate acid for the water. The esters find much use thus, triphenyl phosphite is most widely used in the manufacture of polyvinyl chloride, while trinonylphenyl phosphite is an excellent stabilizer for the same polymer. 

Various polyesters derived from phosphorous or phosphoric acids were prepared. Efiicient polyphosphites were synthesised in the early 196(. Polyphosphite prepared from 152 and 4,4 -isopropylidenebis(cyclohexanol) was tested as a thermal stabilizer for PC [199] or as secondary AO for radiation sterilized EPM [200]. Built-in phosphites obtained by transesterification of triallcylphosphite with 4,4 -isopro-pylidenebisphenol or 4,4 -thiobisphenol possess antioxidant properties in polyolefins. Stabilizer containing phosphite moiety 153 was prepared from tris(2-hydroxy-ethyl)isocyanate, decyl alcohol and triphenylphosphite [201]. Various phosphites were derived firom polynuclear phenols or dihydric phenols. For example, a polycondensate prepared by reaction of phosphorus trichloride with 2,5-di-rert-butylhydroquinone was tested as heat and light stabilizer for PP [202], A linear polyester with a built-in phenolic moiety was synthesised from (2,6-di-tm-butyl-4-methylphenyl)bis(6-hydroxyhexyl)phosphite and dimethyl terephthalate [203]. 

Phosphite processing stabilizer for polypropylene, polyethylene, and adhesives. 

An optimized blend of liquid phenolic antioxidant and liquid aromatic amine antioxidant with a small amount of a phosphite stabilizer. This blend was specifically developed for use as a heat and color stabilizer for polyols used for making flexible polyurethane foam. 

Catalytic cyclopropanation of alkenes with diazomalonates is sometimes carried out with copper powder, but it appears that copper(I) halide/trialkyl phosphite complexes (for a procedure see Houben-Weyl Vol. E19b, p 1113), bis(acetylacetonato)copper(II), " ° and tet-raacetatodirhodium can be employed more advantageously (Table 13, entries 7-9). For the cyclopropanation of styrene with dicyclohexyl diazomalonate, however, copper(I) triflate was the catalyst of choice, while intramolecular C —H insertion at the cyclohexyl ring took place in the presence of tetraacetatodirhodium. A detailed comparison of copper catalysts for the cyclopropanation of cyclohexene, 1-methyl- and 1,2-dimethylcyclohexene, (Z)- and ( )-hept-2-ene with dimethyl diazomalonate, including competitive reaction pathways such as allylic C-H insertion and carbene dimer formation, is available. The catalyzed interaction between diazomalonic esters and enol ethers leads to cyclopropanes in some cases (e.g. ethoxymethylenecyclohexane to dimethyl 2-ethoxyspiro[2.5]octane-l,l-dicarboxylate ) and to different products in other cases (e.g. 1-methoxycyclohexene, 2-methoxy-3,4-dihydro-2/7-pyran ). This behavior is attributed to the occurence of stabilized dipolar intermediates in these reactions. 

In a previous paper, the effectiveness of certain hindered mono phosphites and phosphonites as processing stabilizers for polyolefinsC1) was discussed. 

Wytox L [Uniroyal] Phosphites or hindered phenols antioxidant stabilizer for plastics and rubber. 

Doverphos DPIOP DPIOP EINECS 247-658-7 Isooctyl diphenyl phosphite Phosphorous acid, isooctyl diphenyl ester Weston ODPP. Color stabilizer for ABC, PC stabilizer for PVC antioxidant... 

EINECS 246-614-4 Isooctyl phosphite ((C8H170)3P) Phosphorous acid, triisooctyl ester Triisooctyl phosphite Weston TIOP. Intermediate insecticides lubricant additive specialty solvents stabilizer for acrylics, nylon, unsaturated polyester, PVC improves antiwear and antifriction properties. Stabilizer tor hot-melt adhesives. PU, polyesters used in molding, extrusion, and film applications in PP, HOPE, LDPE, PVC, and polyesters also useful for PP fiber applications and calendering of PVC. Oil d = 0.891. Albright i Wilson Americas Inc. GE Specialities Stave. 

Both yellowing and embrittlement of polypropylene are dose dependent but are significant at or around 25 kGy (the customary compendial dose for sterilizing medical devices). The extent of radiation-induced discoloration can be relieved by use of phosphite stabilizers. Stability against embrittlement may be improved by adding antioxidants, but these may in turn create problems such as surface blooms. ... 

The transesterification reactions in PBT/PC melt blends could be suppressed by using organo-phosphites and phosphonates which probably function by deactivating the titanium or antimony type polymerization catalyst residues present in PBT [Golovoy et al., 1989]. Even in the presence of phosphite stabilizers, PBT/PC blends showed dual phase behavior. However, a partial miscibility was evident since the T of PC phase was still reduced from the normal 150°C to about 140°C. This partial miscibility between PBT and PC which occurs even in the absence of an exchange reaction is responsible for the good compatibility and interfacial strength of the blend. 

It should be remembered that additives used for one type of resin may have detrimental effects on another resin and/or on its additives. It was reported that the interfacial properties in PA/PO blends can be seriously affected by incorporation of unsuitable additive into a blend. When PA scrap was mixed with PO containing phosphite stabilizers, a rigid membrane was formed at the interface by a chemical reaction between -NH groups of PA and phosphite acidic functionality [Luciani et al., 1997]. The membrane has two serious effects it increases the melt viscosity (thus, it reduces the throughput), and it makes dispersing the PO in PA much more difficult (what reduces the performance). The detrimental effects are most likely when heat and light stabilizers are present in the recyclates. 

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