Soft PVC foams: Study of the gelation,fusion, and foaming processes. II. Adipate,citrate and other types of plasticizers

Plasticized poly(vinyl chloride) (PVC) is one of the most useful polymeric materials on an industrial scale because of its processability, wide range of obtainable properties, and low cost. PVC plastisols are used in the production of flexible PVC foams. Phthalates are the most used plasticizers for PVC, and in a previous article (part I of this series), we discussed the influence of phthalate ester type plasticizers on the foaming process and on the quality of the foams obtained from the corresponding plastisols. Because the use of phthalate plasticizers has been questioned because of possible health implications, the objective of this work was to undertake a similar study with 11 commercial alternative plasticizers to phthalates. The evolution of the dynamic and extensional viscosity and the interactions and thermal transitions undergone by the plastisols during the heating process were studied. Foams were obtained by rotational molding and were characterized by the determination of their thermomechanical properties, density, and cell size distribution. Correlations were obtained between the molecular weight and structure of the plasticizer and the behavior of the corresponding plastisols. After the characterization of the final foamed product, we concluded that foams of relatively good quality could be prepared with alternative plasticizers for replacing phthalates. Several plasticizers {Mesamoll (alkylsulfonic phenyl ester), Eastman 168 [bis(2‐ethylhexyl)‐1,4‐benzenedicarboxylate], Hexamoll [di(isononyl) cyclohexane‐1,2‐dicarboxylate], Citroflex A4 acetyl tributyl citrate (ATBC), and Plastomoll (dihexyl adipate)} were found to be interesting alternatives in the production of soft PVC foams because they provided very good quality foams with properties similar to, or even better than, those obtained with phthalate plasticizers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Optimizing performance of benzoate and phthalate blends for vinyl applications

To achieve required performance, blends of plasticizers are commonly used in flexible vinyl applications. Typically, when fast fusion is required, high solvating phthalates have been utilized in plasticizer blends. Benzoate esters are high solvators and can also be used in these blends. However, even though benzoate plasticizers offer additional performance benefits that can complement general‐purpose phthalate performance, most of the literature does not include the use of benzoate plasticizers in blends with phthalates. The purpose of this article is to demonstrate the performance benefits of blending benzoate and phthalate plasticizers. The approach selected to accomplish this task was to develop performance data by utilizing a mixture design approach with DOE (design of experiments) software. A resilient flooring plastisol formulation was selected as the model. The following properties were obtained: degassing, low and high shear viscosity, viscosity stability of the plastisol, gel and fusion characteristics, tensile strength vs. temperature, vinyl heat stability, stain resistance, volatility, and UV stability. The data indicate how to utilize the advantage of benzoates as “process aids” to speed production rates and improve product quality. J. VINYL. ADDIT. TECHNOL. 11:150–154, 2005. © 2005 Society of Plastics Engineers     

Application of new oligomeric plasticizers based on waste poly(ethylene terephthalate) for poly(vinyl chloride) compositions

In this study, chemical recycling products of waste poly(ethylene terephthalate) with oligoesters were used as new plasticizers for poly(vinyl chloride) (PVC). The preparation conditions of the dry blend mixtures of the suspension PVC containing synthesised plasticizers were similar to the conditions of the preparing mixtures with commercial plasticizers. The plasticization efficiency of PVC plasticizers was then examined by analysis of the mechanical, physical and chemical properties, as well as the thermal resistance and migration of plasticizer molecules from polymer matrix. Test results proved that compositions with synthesised oligomeric plasticizers possessed similar or better properties than those containing commercial oligomeric plasticizers and much better properties than those having monomeric plasticizers. Thermal stabilities of the proposed plasticizers were higher than those of the commercial plasticizers either monomeric (bis(2-ethylhexyl)phthalate) or oligomeric, despite the fact that the synthesised oligoesters did not contain any antioxidant. The best properties, especially low volatility, very good mechanical properties, low migration were resulted of the transesterification of the waste PET with oligoesters based on adipic acid, triethylene glycol and 2-ethylhexanol which were selected as plasticizers synthesised on the technical scale. The tested plasticized PVC compositions possessed very good tear resistance, tensile strength, decrease of weight loss after 168 h at 80 °C and low migration. Processing properties of PVC compositions containing these synthesised plasticizers confirmed their effectiveness in these compositions for extrusion process.     

增塑剂在吸收片中迁移的研究

定量分析了邻苯二甲酸酯类增塑剂如邻苯二甲酸二正辛酯(DNOP)、邻苯二甲酸二辛酯(DOP)、邻苯二甲酸二甲酯(DMP)以及环保型增塑剂二丙二醇二苯甲酸酯(DPGDB)在吸收片中的迁移。结果表明,不同的吸收片,增塑剂的迁移量不同,在乙烯-乙酸乙烯酯共聚物(EVA)中发生的迁移最大,高密度聚乙烯(HDPE)最小。在压力为49N,温度70℃,试验时间为24h时,增塑剂DOP在吸收片EVA中的质量损失高达141.7mg,而在HDPE中仅有15mg。     

A monomeric plasticizer for high temperature applications

The results of this study demonstrate that high molecular weight and predominantly linear diundecyl phthalate (DUP) provide improved performance properties and cost savings when used as a partial or total replacement for trimellitate plasticizers in critical applications such as vinyl electrical insulations and crashpad covers. DUP is shown to be a permanent and stable plasticizer with a high efficiency in improving low-temperature flexibility of formulated vinyls.     

Low‐molecular‐weight glycerol esters as plasticizers for poly(vinyl chloride)

Phthalates are the most important plasticizers used in the polymer industry. However, their fossil origin and the results of recent tests showing their potential negative effect on human health have encouraged the polymer industry to turn toward non‐phthalate plasticizers. At the same time, the biodiesel industry produces a surplus of glycerol, thus leading the scientific community to seek new applications for this substance. This paper presents the performance of eight esters derived from glycerol as plasticizers for poly(vinyl chloride), including tests to evaluate their compatibility. Results show that glycerol esters obtained from propanoic, butanoic, isobutanoic, isopentanoic, and benzoic acids, while volatile, can be used as poly(vinyl chloride) plasticizers in certain applications. J. VINYL ADDIT. TECHNOL., 20:65–71, 2014. © 2014 Society of Plastics Engineers     

How about alternatives to phthalate plasticizers?

Phthalate plasticizers have historically served as the preferred plasticizers to impart flexibility to PVC and several other polar polymers. They provide a desirable balance of cost and performance properties. Their acceptable and safe use is unmatched in medical appliances, food processing, and packaging applications, as well as in many other end uses. Potential alternatives do not have the historical record of acceptable performance found with phthalate plasticizers. Nevertheless, the “Precautionary Principle” has caused certain segments of society to clamor for alternates to phthalate plasticizers. This paper reviews known “non‐phthalate” plasticizers and provides comparisons to the traditional “General Purpose” (GP) phthalate plasticizers; “General Purpose” plasticizers are those that impart optimum overall performance properties in PVC at lowest cost.     

Dialkyl furan‐2,5‐dicarboxylates,epoxidized fatty acid esters and their mixtures as bio‐based plasticizers for poly(VInylchloride)

Dialkyl furan‐2,5‐dicarboxylates and epoxidized fatty acid esters (EFAE) of varying molecular weights and volatilities, as well as their mixtures, were investigated as alternative plasticizers for poly(vinylchloride) (PVC). The EFAE utilized were epoxidized soybean oil (ESO) and epoxidized fatty acid methyl ester (e‐FAME). All plasticizers were compatible with PVC, with plasticization efficiencies usually increasing with decreasing molecular weights of the plasticizers (except in the case of ESO, which was remarkably effective at plasticizing PVC, in spite of its relatively high molecular weight). In comparison with phthalate and trimellitate plasticizers, the alternatives generally yielded improved balance of flexibility and retention of mechanical properties after heat aging, with particularly outstanding results obtained using 30?50 wt % e‐FAME in mixtures with diisotridecyl 2,5‐furandicarboxylate. Although heat aging characteristics of the plasticized polymer were often related to plasticizer volatilities, e‐FAME performed better than bis(2‐ethylhexyl) 2,5‐furandicarboxylate, and bis(2‐ethylhexyl) phthalate of comparatively higher molecular weights. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42382.     

Synthesis of bis(2,4-diphenylbutyl) phthalate and its application as a plasticizer for poly(vinyl chloride) from waste polystyrene

Bis(2,4-diphenylbutyl) phathalate, a plasticizer for poly(vinyl chloride) (PVC), was synthesized from 2,4-diphenyl-1-butene obtained by a thermal decomposition under reduced pressure of waster polystyrene. The heat stability of bis(2,4-diphenylbutyl) phthalate was determined by thermogravimetric analysis and compared with typical plasticizers. It was recognized that bis(2,4-diphenylbutyl) phthalate showed high heat resistant. A test sheet of plasticized PVC with bis(2,4-diphenylbutyl) phthalate and bis(2-ethylhexyl) phthalate was prepared. The test sheet was used for determination of the plasticizing performance of bis(2,4-diphenylbutyl) phthalate. Although the effect of bis(2,4-diphenylbutyl) phthalate imparting flexibility to PVC is poorer than that of bis(2-ethylehexyl) phthalate, the former phthalate is well compatible with PVC and exceedingly heat-resistant.     

Highly filled blends of a vinylic copolymer with plasticized lignin: Thermal and mechanical properties

The objective of this study was the development of new vinyl flooring formulations with increased resistance to attack by fungi and microorganisms, formulated with plasticizers having chemical compositions different from that of common dioctyl phthalate (DOP). Alkyl phthalate plasticizers are considered to be toxicological and ecotoxicological hazards, although this is still under debate. It is suspected that during the service life of poly(vinyl chloride) (PVC) flooring, the attack of fungi and microorganisms leads to the degradation of DOP and the release of some volatile organic compounds. For this reason, in the new flooring formulations, the vinyl chloride/vinyl acetate copolymer (VC–VAc) was partially replaced with lignin, a natural polymer and a major component of wood and vascular plants. Besides its other functions in wood, lignin imparts resistance to microorganisms. An organosolv lignin from Alcell Technologies, Inc. (AL), was used as a partial replacement of PVC. The influence of the new plasticizers, as well as the influence of the partial replacement of VC–VAc with lignin, on the morphology and thermal and mechanical properties of the composites was investigated with scanning electron microscopy, differential scanning calorimetry, and tensile testing. Butyl benzyl phthalate and diethylene glycol dibenzoate were used as plasticizers; both were compatible with PVC and AL. The results indicated that diethylene glycol dibenzoate was the best plasticizer for these blend composites. In these formulations, AL could replace up to 20 parts of the copolymer. At this level of replacement, the key mechanical properties of the new composites compared very favorably with those of the DOP control formulations. The obtained formulation will be tested further for resistance to fungi and microorganisms. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2000–2010, 2003     

Properties of a PVAc emulsion adhesive using a nonphthalate plasticizer obtained by condensation of 2-methylpropanal

The requirement to search for new plasticizers and coalescents for making water-based dispersion adhesives from poly(vinyl acetate) is of particular importance, especially now, after banning all kinds of toxic phthalates and restricting the use of glycol derivatives classified as volatile organic compounds. The poly(vinyl acetate) adhesive was synthesized using the eco-safe plasticizer – 3-hydroxy-2,2,4,-tri-methyl pentyl isobutyrate. The plasticizer was obtained by aldol condensation of 2-methylpropanal, byproduct of oxy synthesis from propylene. Its desirable properties were confirmed by comparing the composition of the adhesive comprising poly(vinyl acetate) as the principal component and the plasticizer as the additive. 3-hydroxy-2,2,4,-tri-methyl pentyl isobutyrate and commonly known plasticizers, such as: diisobutyl phthalate and diethylene glycol n-butyl ether acetate were used as the plasticizers in the experiment. The adhesives were compared in respect of the following parameters: dry weight, pH, viscosity, minimum film forming temperature, penetrability, setting time and stability in time. The test results indicate that 3-hydroxy-2,2,4,-tri-methyl pentyl isobutyrate can be used successfully as a plasticizer for making wood adhesives in the range from 2.0 to 2.5% of the adhesive formulation and for making bookbinding adhesives in the range from 4.7 to 5.6% of the adhesive formulation. This enables an about twofold reduction of the amount of the plasticizer, in comparison with the adhesive based on diisobutyl phthalate. 3-hydroxy-2,2,4,-tri-methyl pentyl isobutyrate can be used in dispersion adhesive formulations, thus replacing the undesirable, toxic phthalate esters and polyglycol derivatives classified as volatile organic compounds.     

The effects of plasticizers on the properties of poly(vinyl chloride) foams

The effects of plasticizers on poly(vinyl chloride) (PVC) plastisol mixtures were investigated. The investigations were carried out by determining the density of the PVC foam obtained by gelling the plastisol, as well as its elasticity and degree of expansion. Two series of experiments using different types of PVC were performed, using eight plasticizers, individually or as mixtures. Two-component plasticizer mixtures showed better properties than single-component plasticizers, and mixtures of di-iso-heptyl phthalate (DiHP) and butyl benzyl phthalate (BBP) proved to be the most appropriate. The effect of plasticizer amount also was investigated, and of the three parameters studied, the foam density, which steadily increased with plasticizer amount, was the critical one. It was also shown that in order to obtain consistent results, the foam expansion had to be precisely timed and the temperature carefully chosen.     

Preparation and evaluation of acetylated mixture of citrate ester plasticizers for poly(vinyl chloride)

Tributyl citrate (TBC) and acetyl tributyl citrate (ATBC), as phthalate alternative plasticizers, show limited application due to low migration resistance, high volatilization rate and intense respiratory irritation. Meanwhile, the developed pure citrates, such as butyryl trihexyl citrate (BTHC) due to its high cost, and triisooctyl citrate (TOC) and acetyl triisooctyl citrate (ATOC) due to their low absorption property, are not attractive plasticizers to manufacture phthalate-free poly(vinyl chloride)s (PVCs). In this study, we developed an effective method to synthesize acetylated mixture of citrate esters (ATMC) composed of acetyl (dibutyl-monoisooctyl) citrate, acetyl (monobutyl-diisooctyl) citrate, and a small amount of ATBC and ATOC, as an alternative for phthalate plasticizers. ATMC combines the advantages of ATBC in being easily absorbed and ATOC in having good migration resistance. Characterization results showed that the dynamic viscosity, absorption property and plasticizing efficiency of ATMC11 (1:1 molar ratio of n-butyl alcohol to 2-ethylhexanol) were similar to those of di(2-ethylhexyl) phthalate (DEHP). The thermal volatilization and migration of ATMC11 were less than those of ATBC, and were comparable to those of DEHP, which could be attributed to the improved compatibility with PVC. The performance of ATMC11 was improved compared with that of the mixture of ATBC and ATOC. As an environmental bio-based plasticizer, ATMC11 was demonstrated as a biologically safe plasticizer by biological safety evaluation tests. Therefore, ATMC11 with excellent comprehensive performances and low cost can be candidate as an ideal phthalate alternative for soft PVC formulations.     

Plasticizers derived from cardanol: synthesis and plasticization properties for polyvinyl chloride(PVC)

Two natural plasticizers derived from cardanol (CD), cardanol acetate (CA) and epoxidized cardanol acetate (ECA), were synthesized and characterized by ¹H NMR and ¹³C NMR. The plasticizing effects of the obtained plasticizers on semi-rigid polyvinylchloride (PVC) formulations were also investigated. Two commercial phthalate ester plasticizers, dioctyl terephthalate (DOTP) and diisononyl phthalate (DINP), were used as controls. Mechanical and thermal properties, compatibility, thermal stability, microstructure, and workability were assessed by dynamic mechanical analysis (DMA), mechanical analysis, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and dynamic stability analysis, respectively. Results indicated that the natural plasticizer ECA had overallsuperior flexibility, compatibility, thermal stability, and workability comparable to both controls. The obtained CA and ECA have lower volatility resistance and similar extraction and exudation resistance than that of DOTP and DINP. The CA was further blended with DOTP in soft PVC films. Results of DMA, TGA and mechanicalanalysis indicated that CA can serve as a secondary plasticizer to improve the related properties of soft PVC formulations. These CD derived plasticizers show promise as an alternative to fully or partially replace petroleum-based plasticizers.     

Effects of Plasticizers and Stabilizers on Thermal Stability of Polyvinyl Fluoride

The study was focused on the choosing of plasticizers and stabilizers for improving thermal stability of polyvinyl fluoride (PVF) during the thermoplastic processing. Five kinds of organic esters as plasticizers for PVF were evaluated. The results showed that dimethyl phthalate (DMP) had better compatibility with PVF and phase separation didn't occur up to a relatively high concentration level, and DMP significantly decreased the melting temperature of PVF and showed the good plasticized effect. The optimum DMP content, considering homogeneous compound, good melt fluidity, and dynamic thermal stabilization, can be determined from the melt flow index and torque measurements. Five kinds of additives as stabilizers for PVF/DMP system were evaluated by the color change during static ageing. It was found that pentaerythritol had remarkably positive effects on both thermal and color stability of PVF.     

增塑剂的热压力系数及新溶解度参数

实验测定了邻苯二甲酸二甲酯、丙二酸二乙酯、磷酸三乙酯、磷酸三丁酯、草酸二丁酯和癸二酸二丁酯等 6种增塑剂在 2 5～ 85℃温度范围的热压力系数和密度 ,并用推广的vanderWaals模型关联了这些实验数据 ,开发了一个能够预测增塑剂内压的方法 ,据此得到 30种常用增塑剂的新溶解度参数值     

Synthesis and evaluation of some fatty esters as plasticizers and fungicides for poly(vinyl acetate) emulsion

n-Fatty alcohols (average molecular weight 187), prepared from n-paraffins, were treated with a series of dibasic acids such as malonic, succinic, glutaric, adipic and phthalic anhydride to give the corresponding fatty esters. The prepared fatty esters were formulated with poly(vinyl acetate) emulsion and used as films or textile coatings. Tests such as rate of drying, mechanical properties and resistance to micro-organisms were carried out. Samples of poly(vinyl acetate) plasticized with dibutyl phthalate were also prepared and evaluated for the purpose of comparison. The antifungal activity of these compounds was studied. The results obtained indicate that the prepared fatty esters can be used not only as plasticizers but also as fungicides and in some respects they are better than the conventional dibutyl phthalate plasticizer.     

Formulation and mechanical characterization of PVC plastisols based on low‐toxicity additives

New formulations of plastisols based on low‐toxicity plasticizers were proposed and characterized. Traditional phthalate plasticizers were replaced in the plastisols studied in this research by polymeric plasticizers (i.e., saturated polyesters), produced by the reaction of a diol and a carboxylic acid. The main drawback for the use of these plasticizers in formulations of PVC plastisols is a significant increase of the paste viscosity, which decreases their processability; thus, the use of additional additives to reduce viscosity is recommended. This study also includes the optimization of the processing conditions (cure temperature and time) of the proposed plastisols: complete cure was obtained at 140°C and 10 min. It is reported that the final properties of plastisols are very sensitive with respect to the processing conditions; in fact, insufficient plasticization or degradation can affect the material when processed out of the optimum conditions. The influence of the plasticizer concentration on mechanical and optical properties, such as tensile strength, hardness, brightness, and the like, is also reported. In summary, the proposed plastisols, with low‐toxicity plasticizers, offer a valid alternative to traditional PVC plastisols based on phthalate plasticizers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1881–1890, 2001     

Soft PVC foams: Study of the gelation,fusion, and foaming processes. I. Phthalate ester plasticizers

The use of foamed plastics gains more and more interest every day. Flexible poly(vinyl chloride) (PVC) foams have excellent mechanical properties and low price, thus their application is extensive. Foams are produced from plastisols, which are based on the suspension of the PVC resin in a plasticizer. Phthalates are the most used plasticizers in flexible PVC foam formation. In this study, we have studied the influence of the phthalate ester‐type plasticizers on the foaming process and the quality of the foams obtained from the corresponding plastisols. For the plastisols prepared with the nine phthalate plasticizers considered, we have studied and discussed the complex and extensional viscosities; the thermal behavior (DSC) including the decomposition of the chemical blowing agent, and the foam production by rotational molding. In addition, we have characterized the foams obtained by thermomechanical analysis, density, and bubble size distribution. As expected, clear correlations have been obtained between the molecular weight and structure of the plasticizer with the rheological behavior of the plastisols. The knowledge of the gelation and fusion processes and evolution of the extensional viscosity of the plastisols combined with the study of the thermal decomposition of the blowing agent in each plastisol allows for better understanding of the complex dynamic behavior of these foaming systems. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Plasticizer structure/performance relationships

Plasticizers for poly(vinyl chloride) may be organized into eight chemical families and by seven key performance criteria. Cost-effective general-purpose phthalates provide a base line for comparing all other plasticizers. The wide range of performance characteristics associated with various phthalate isomers substantiates the large proportion of phthalate esters that are utilized as plasticizers. This article summarizes plasticizer structural/performance relationships using quantitative comparisons of cost, plasticizing efficiency, plastisol solvation characteristics, dryblending, volatility, and low temperature performance properties in PVC. Some generalizations are also made concerning structural effects of the alcohol isomers used in the syntheses of the various types of plasticizer esters.