New polyvinylchloride plasticizers

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New polyvinylchloride plasticizers. by Mazitova A.K., Aminova G.K., Maskova A.R., Sabitov I.N. is licensed under a ...

P olyvinylchloride (PVC) is one of the most demanded large-capacity polymers made in Russia and abroad, following only polyethylene by production volume. The range of materials and products based on it continues to grow, because they meet the high requirements of modern processing and operating conditions [1–4].

Further development of polyvinylchloride production accompanied by continuous extention of scope first of all is determined by development of functional chemicals additives – stabilizers and plasticizers.

Stabilizers are introduced into composition of polymers to decelerate their ageing that caused mainly by destruction. A large number of chemical

SOLUTIONS FOR ECOLOGICAL PROBLEMS compounds are used as stabilizers: heat stabilizers reduce harmful effects of thermal and thermooxidizingdegradation of polymer; antiozonants protect polymers from effect of atmospheric oxygen and ozone; light stabilizers slow down aging of polymers under the influence of ultra-violet light; antirads protect polymers from destruction under the influence of high-energy radiations; passivators of polyvalent metals protect polymers from the destroying effect of metal «poisons»; antifatiguesprotect polymeric materials, mainly rubbers, from cracking at action of variable loadings [5–7].

The largest segment of the additives market is the market of plasticizer. Introduction of plasticizer into polymeric composition makes it possible to produce material with specified elasticity for the wide range of temperatures. The proper selection of polymer facilitates the polymer processing, greatly increases the frost resistance, flame resistance and improves many other properties of polymer soft products [8].

Various classes of chemical compounds are studied and used as plasticizers: esters ofterephthalic, aliphatic, dicarboxylic, trimellitic and pyromellitic acids; polyester and phosphoricesters; epoxidizedester of soy, palm oils, of tallow fatty acids and other compounds (for example, higher alcohols from C18, paraffin wax) [9, 10].

In recent years there has been a purposeful development of chemical additives. Thus complex stabilizers containing all necessary components, including lubricants have been already in use. Toxic cadmium, barium, leadcontaining heat stabilizers are replaced by non-toxic carboxylates of alkaline earth metals. New plasticizers, giving to plastic compound specific properties, are developed [11].

This paper presents the results of research on development of PVC films compositions with new oil and petrol-resistant plasticizers.

Preobtained calcium-zinc complex salts of oleic, stearic and alpha branched saturated monocarboxylic acids (VIC) were used as heat stabilizers [12, 13].

Phthalates of oxyalkylated alcohols (Fig. 1). Initial oxylated and hy-droxypropylated butanol and phenol obtained previously were used as plasticizers [14–17].

Conditions for obtaining the desired products are shown in Table 1, physicochemical parameters are given in the Table 2.

Obtained esters were tested as PVC plasticizers in compositions of PVC films.

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Ri

COO(CH3CHO)nR2

COO(CH3CHO)nR2

COO(CH3CHO)nR4

R3

where R1 = H, R2 = C4H9, R3 = H, R4 = C4H9 (I); R1 = CH3, R2 = C4H9, R3 = CH3, R4 = C4H9 (II); R1 = H, R2 = C6H5, R3 = H, R4 = C6H5 (III); R1 = CH3, R2 = C6H5, R3 = CH3, R4 = C6H5 (IV); R1 = H, R2 = C6H5, R3 = H, R4 = C4H9 (V); R1 = CH3, R2 = C6H5, R3 = CH3, R4 = C4H9 (VI); R1 = CH3, R2 = C6H5, R3 = H, R4 = C4H9 (VII); R1 = H, R2 = C6H5, R3 = CH3, R4 = C4H9 (VIII).

Fig. 1

Compositions of the films and the experiment result of obtained esters as plasticizers in commercial formulations of PVC films are shown in Table 3 (Formulation (wt parts): PVC – 100; plasticizer – 50; Ca–Zn complex stabilizer – 3.0).

Prepared compositions were milled in laboratory mill 320 PD at the temperature of 160–162оC for 10 minutes. There were no any difficulties during rolling of composition: the film didn’t stick to the rolls, holes, chips and cracks were absent in the obtained samples of plastic. Moreover, during the production of PVC compositions in the mixer and their processing on rollers technological difficulties did not arise.

Physical, physicochemical and physico-mechanical properties were determined in accordance with standard methods. The strength and elongation

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The optimum conditions for obtaining chemical additives

Physicochemical parameters of synthesized esters

Table 1

№	Reagent molecularratio		Temperature, оС	Note
1	alcohol : ethylene (propylene) oxide	1:1.3-2.2	110–180	amount of catalyst 0.5–3% (wt. by loading)
2	phthalic anhydride: oxyalkylated alcohol	1:2	121–170	amount of catalyst 0.1–2% (wt. by loading) + activated carbon in an amount of 1% (wt. of weight of the loaded components)

Table 2

Indicator name	Plasticizers
	I	II	III	IV	V	VI	VII	VIII
Oxyalkylation degree, n	2.0	2.2	1.0	2.1	2.0*	2.2*	2.0*	2.2*
Density, d204	1.4816	1.4745	1.1086	1.1002	1.1081	1.1050	1.1062	1.1060
Index of refraction, 20 nD	1.0757	1.02991	1.5194	1.4924	1.5183	1.5174	1.5178	1.5178
Acid number, mg КОН/g	0.1	0.4	0.1	0.1	0.2	0,2	0,2	0.2
Ether index, mg КОН/g	243	207	273	198	257	203	211	235
Molecular mass, found	461	541	411	566	436	553	514	476
Freezing temperature, о С	–50	–44	–40	–39	–40	–37	–39	–40
Weight fraction of volatile compound (100оС, 6 h ),%	0.25	0.25	0.10	0.15	0.10	0.10	0.12	0.10
Flash-point, оС	200	Higher than 200	200	199	200	200	200	200

* phenol ethoxylation degree = 1.0; phenol hydroxypropylation degree = 2.1

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Physicochemical parameters of synthesized esters

Table 3

Indicator name Test samples I II III IV V VI VII VIII Stress at elongation 100%, MPa 11.9 11.8 12.5 12.4 12.1 12.2 12.1 12.2 Breaking stress, MPa 22.6 22.4 23.1 23.0 22.9 23.0 22.8 23.1 Elongation at break, % 286 287 289 289 287 289 288 288 Frost resistance, оС –34 –34 –37 –39 –34 –34 –36 –37 Mass losses at 130оС, during 6 h., % 2.1 2.2 2.5 2.7 2.8 2.6 2.8 2.7 Extractibility by water, % 0.305 0.301 0.324 0.325 0.319 0.316 0.318 0.316 Water absorption ability, % 0.472 0.469 0.484 0.486 0.474 0.478 0.479 0.477 Extractibility by petrol, % 3.15 4.27 1.48 1.47 1.44 1.44 1.45 1.44 Extractibility by oil, % 12.8 13.1 10.5 10.6 10.7 10.8 10.8 10.9 Melt flow index, g/10 min. 39.8 39.6 40.4 40.2 40.0 40.3 40.1 40.0 Heat stability at 175оС 169 167 175 173 170 173 172 172 Longterm film storage at 25оС during 4 month Films are good at break was determined according to GOST (Standard-Setting Authority) 11262-80 at temperature (23±2)оC on preconditioned (GOST 12423-66) samples; a melt flow rate (MFR) according to GOST 11645-73 on extrusion type plastometer brand IIRT-5; while measurement of the brittleness temperature of PVC compounds were performed by express method in accordance with GOST 16782-92 in three samples which size is 130x10 mm and thickness is 1±0,1 mm; the thermal resistance of PVC compositions were evaluated according to GOST 14041-91 in terms of «time of heat stability». Time of heat stability was determined by time of an inductive discoloration of the «congo red» indicator at a temperature of 180оC and selections of HCl during polyvinylchloride destruction. Assessment of the technological properties of the developed PVC compounds was carried out with Brabender plastograph, rollers, twin-screw extruder MD 30-19, plastometer MMFT.

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All tested samples of synthesized esters provided PVC films with relevant technical properties. Important technological parameters, such as time of heat stability, melt flow rate, in all cases of the use of test plasticizer samples were much higher, that indicates facilitated processing of the PVC compositions. It should be also noted that the PVC films have improved oil and petrol resistance. In addition, preliminary tests showed that obtained esters belong to the 3 hazard class. As it is known, DOP is a toxic plasticizer, which belongs to the 2 hazard class.

Thus, PVC compounds that contain the new plasticizers by all characteristics meet the existing standards and are recommended for further testing.