Diisononyl Adipate Research Articles

Comprehensive survey on the use of plastic additives in toy products used in Japan.

Plastic additives have adverse effects on human health. Children frequently use toys that contain various substances found in paints, plasticizers, and other materials, which heighten the risk of specific chemical exposure. Infants are particularly prone to chemical exposure through the "mouthing" behavior because of the possibility of placing toys in their mouths. Thus, this vulnerability should be considered during risk assessments of chemical exposure. This study performed a comprehensive analysis of the chemical components in various 84 plastic toys including "designated toys" (toys that may be harmful to infant health if in contact with their mouths: Article 78 of the Enforcement Regulations of the Food Sanitation Law by the Minister of Health, Labor and Welfare) such as dolls, balls, blocks, bathing toys, toy vehicles, pacifiers, and household items, purchased in the Japanese market by nontargeted and targeted analysis. Plasticizers, flame retardants, and fragrances were the main compounds in almost all the toy products. The results showed that plastic products made in China tended to contain high levels of phthalate esters. In particular, hazardous plasticizers, such as diisodecyl, di-n-octyl, and diisononyl phthalates were detected above the regulatory limit (0.1%) in used products manufactured before regulations were passed in Japan. Furthermore, we detected alternative plasticizers, such as acetyl tributyl citrate (ATBC; 52%), diisononyl adipate (DINA; 50%), and di(2-ethylhexyl) terephthalate (DEHT; 40%). ATBC was detected at high concentrations in numerous toy products. Thus, infants with free access to indoor plastic toys might be exposed to these chemicals. This study observed that the chemical profiles of toy products were dependent on the year of manufacture. Furthermore, the detection of currently regulated plasticizers in secondhand products manufactured before regulations were enforced, along with the increasing trend of using alternative substances to regulated phthalate esters in products, suggests the potential exposure of infants to these plasticizers through the use of toys. Therefore, regular fact-finding surveys should continue to be conducted for the risk assessment and safety management of domestic toy products.

Exposure to airborne PM<sub>2.5</sub> chemical exposome increases heart rate of middle- and old-aged populations

<p>Previous studies have rarely focused on the effects of industrial chemicals on heart rate. There is also a lack of epidemiological investigations to elucidate the mixture effects of complex components of fine particulate matter (PM<sub>2.5</sub>) on cardiovascular health and identify the key toxic components. Here, a population health-oriented methodology is established to quantify mixed effects of airborne PM<sub>2.5</sub> chemical exposome and identify key components. This methodology was applied to a cross-sectional study to elucidate the mixture effect of industrial chemical components of PM<sub>2.5</sub> on the heart rate of middle- and old-aged populations (including 373 people from seven Chinese cities) and further identify key chemical components for the effect. Exposure to seven groups of industrial chemicals, including phthalate esters (PAEs), adipate esters (AEs), benzothiazoles and benzotriazoles (BTHs & BTRs), benzophenones and benzoates (BZPs & BZAs), bisphenols (BPs), alkyl organophosphate esters (alkyl-OPEs) and aryl organophosphate esters (aryl-OPEs), was observed to significantly increase the heart rate of study participants. Seven chemicals, including dimethyl isophthalate (DMiP), di-iso-nonyl adipate (DiNA), 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV-328), ethyl-4-aminobenzoate (EAB), bisphenol F (BPF), triethyl phosphate (TEP) and tricresyl phosphate (TCrP), were identified as the key components driving the adverse effect on heart rate. Our study highlights the cardiovascular hazards of airborne PM<sub>2.5</sub> chemical exposome.</p>

Quantitative investigation of the urinary excretion of three specific monoester metabolites of the plasticizer diisononyl adipate (DINA).

Diisononyl adipate (DINA) is a plasticizer used in PVC products as an alternative for restricted phthalate plasticizers. With this study, we provide first data on human DINA metabolism and excretion. We postulated mono(hydroxy-isononyl) adipate (OH-MINA), mono(oxo-isononyl) adipate (oxo-MINA), and mono(carboxy-isooctyl) adipate (cx-MIOA) as specific DINA metabolites based on the known human metabolism of structurally similar adipates and phthalates. Urinary excretion was quantitatively investigated after a single oral dose (113 to 145 µg/kg body weight) to three healthy volunteers using a newly developed online-SPE-LC-MS/MS method with isotope dilution and LOQs between 0.3 - 0.6 µg/L. OH-MINA turned out to be the major of the three metabolites with consistent urinary excretion fractions (FUEs) of 0.020-0.023 % among all volunteers. Oxo-MINA and cx-MIOA were excreted with lower shares (mean: 0.003 % and 0.009 %, respectively). For all three metabolites, urinary concentrations peaked quickly between 1.4 and 2.3 h post dose with maximum concentrations of 23.1 (OH-MINA), 2.87 (oxo-MINA) and 9.83 µg/L (cx-MIOA). Thus, FUEs and urinary concentrations were rather low for these specific metabolites, with the major share of the dose presumably being excreted as non-specific metabolites such as adipic acid. In a pilot population (n=35) of German adults without known DINA exposure, we could not detect any of the three metabolites, contrary to the dosage study, indicating to population exposures lower than 50 µg/kg body weight/day. The new HBM method in conjunction with the new FUEs can be used for objective DINA exposure and risk assessment especially in populations with potentially higher DINA exposures.

Impact study of new formulations based on plasticized polyvinyl chloride (PVC)

The aim of this paper is the determination of the migration and biodegradation of the PVC additives in the soil. Epoxidized Sunflower Oil (ESO) was used as a thermal organic co-stabilizer for PVC; it was obtained by epoxidation of commercial sunflower oil. Two plasticizers were used: dioctyl phthalate (DOP) and diisononyl adipate (DINA). A natural aging test on site in a garden soil (Tizi Ouzou, Algeria) of the PVC samples was investigated for 6 months. The samples were characterized by Fourier transform infrared (FTIR).The morphological changes were followed by scanning electron microscopy (SEM). The evolution of the bacterial growth, identification using biochemical tests, variation of pH and variation of mass were investigated. The results showed that the nature of the plasticizer and heat stabilizer affects the properties of PVC as well as the phenomena of migration and biodegradation.

Preparation of diisononyl adipate in a solvent-free system via an immobilized lipase-catalyzed esterification

Diisononyl adipate is a plasticizer which has excellent property of low temperature resistance and is permitted in food contact materials. In this study, diisononyl adipate was synthesized from adipic acid and isononyl alcohol in a solvent-free system via immobilized lipase-catalyzed esterification. Liquid Eversa lipase from Thermomyces lanuginosus was immobilized on Lewatit VP OC 1600 carrier. The effects of temperature, substrate molar ratio, water activity of enzyme, vacuum, and enzyme loading on the reaction efficiency were investigated. Application of vacuum played a key role to achieve a 100% conversion. The optimal temperature, molar ratio (adipic acid to isononyl alcohol), water activity of enzyme, vacuum were 50 °C, 1:3, 0.75, 13.3 kPa, and 10% (based on weight of total substrate). Under these conditions, 100% conversion was achieved within 6 h.

Migration of nonylphenol and plasticizers from polyvinyl chloride stretch film into food simulants, rapeseed oil, and foods.

Nonylphenol (NP) has been suspected as an endocrine‐disrupting chemical. Japanese polyvinyl chloride (PVC) stretch films contained 0.5–3.3 mg/g of NP and 100–400 mg/g of plasticizers such as diisononyl adipate (DINA), di‐n‐alkyl adipate (DAA), and diacetyllauroyl glycerol (DALG). Migration of NP and plasticizers from PVC stretch films into food simulants (water; 4% acetic acid; 20%, 50%, and 95% ethanol; and heptane), rapeseed oil, and foods was investigated. Plasticizers migrated only in small amounts into aqueous simulants and foods, although they migrated at much higher levels into 50% and 95% ethanol, heptane, rapeseed oil, and fatty foods, whereas NP more easily migrated into aqueous simulants and foods. At 5°C for 24 hr, migration of NP into vegetable and fruit was 2.9%–6.4% of their contents, and that of DINA and DAA was 0.1%–0.3%. The migration ratios of NP into aqueous foods were much higher than those of DINA and DAA. The migration ratio of NP into fatty foods, such as minced tuna and pork, was 33% and 24%, which was almost similar to that of DINA and DAA. The estimated daily intakes of NP and DINA for Japanese individuals of those days were 35 and 1,050 μg, respectively, and should not be associated with any safety concerns.

Effect of inert plasticizers on mechanical, thermal, and sensitivity properties of polyurethane‐based plastic bonded explosives

ABSTRACTMechanical, thermal, and sensitivity properties of plastic bonded explosives (PBX) depend on the type of ingredients in their formulation. Aim of the work is to develop aluminized cast PBX formulations and process conditions by using alternative inert plasticizers to have similar or better properties than PBXN‐109 without compromising sensitivity properties. Although very small portion of total production of plasticizers is used for solid rocket propellant and explosive formulations, they play very significant role in that area. Both inert and energetic plasticizers have involved propellant and explosive formulations to improve process parameters, mechanical properties, and even insensitivity properties of them. Isodecyl pelargonate and dioctyl adipate are the most preferred inert plasticizers in polyurethane based thermoset propellant and explosive formulations. In addition to them, diisononyl adipate and diisononyl phthalate were used and screened as inert plasticizer candidates for aluminized cast PBX formulations. Mechanical, thermal, and sensitivity properties of PBX formulations were studied and compared in detail. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40907.

Soil burial degradation of new bio-based additives. Part II. plasticized poly(vinyl chloride) films

Commercial sunflower oil was epoxidized, and the epoxidized oil (ESO) was used as a new thermal stabilizer for poly(vinyl chloride) (PVC). Plasticized formulations stabilized with ESO and epoxidized soya bean oil as a commercial stabilizer were evaluated for comparison. Two plasticizers were used, dioctyl phthalate and diisononyl adipate. The aging of the PVC samples was investigated in landfill soil for 24 months. The modifications of the structure of the polymer were followed by Fourier, transform infrared spectroscopy. Furthermore, the variations of density and mechanical properties (tensile and Shore D hardness) were considered, and the variations of the mass of the samples, the glass transition temperature (T-g), the molar mass distribution, and the weight loss were followed as a function of duration of soil burial. The morphological changes were tracked by scanning electron microscopy. Results showed that the nature of the plasticizer and heat stabilizer affects the properties of PVC as well as the phenomena of migration and biodegradation.

Migration of new bio-based additives from rigid and plasticized PVC stabilized with epoxidized sunflower oil in soil

Commercial sunflower oil was epoxidized and the epoxidized sunflower oil (ESO) was used as a thermal stabilizer for poly(vinyl chloride) (PVC). Rigid and plasticized formulations stabilized with ESO as a new biodegradable stabilizer and epoxidized soya bean oil (ESBO) as a commercial stabiliser were compared. Two plasticizers were used: dioctyl phthalate (DOP) and diisononyl adipate (DINA). The artificial aging of the PVC samples was investigated under uncontrolled temperature in the laboratory for 4 months. The modifications of the structure of the polymer were followed by Fourier transform infrared spectroscopy (FTIR). The morphological changes were followed by scanning electron microscopy (SEM). Furthermore, the evolution of the bacterial growth, variation of pH and variation of mass were considered.

Estimated daily intake of plasticizers in 1-week duplicate diet samples following regulation of DEHP-containing PVC gloves in Japan

Duplicate hospital diet samples obtained over 1 week in 2001 were analysed to estimate the daily intake of plasticizers and the results were compared with those obtained in 1999. The plasticizers quantified in this study were: dibutyl phthalate, butylbenzyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), di(2-ethylhexyl) adipate (DEHA), diisononyl adipate (DINA) and O-acetyl tributyl citrate (ATBC). Dipropyl, dipentyl, dihexyl and dicyclohexyl phthalate were also analysed but not detected. The analytical procedure for this follow-up study was essentially the same as in the previous one. Detection limits were 0.1–15.6 ng g-1 for each plasticizer. One-week duplicate diet samples provided by three hospitals in three remote prefectures of Japan were analysed as individual meals. DEHP was detected at 6–675 ng g-1 in 62 of 63 meals, significantly lower levels compared with those detected in 1999. Levels of DEHA and DINP also decreased. The mean intake of plasticizers estimated from all samples was 160 μg DEHP day-1, 12.5 μg DEHA day-1, 4.7 μg DINP day-1 and 3.4 μg BBP day-1. Levels of DINA were relatively high in meals from one hospital: in those meals, the average daily intake was 1338 μg day-1. Those of ATBC were also higher in meals from another hospital: the average daily intake was 1228 μg day-1. The sources of DINA and ATBC can be cling-film or sausage packaging.

Material labeling of soft plastic toys and plasticizers in polyvinyl chloride products

We investigated the labeling and content of plasticizers of soft plastic toys. First, we investigated material labeling in 96 products purchased in fiscal years 2000 and 2001. Among these products, 43% of those purchased in fiscal 2000 and 68% of those purchased in fiscal 2001 were labeled. We then investigated the kinds and amounts of plasticizers in 73 soft polyvinyl chloride (PVC) toys. Three kinds of phthalates and six other kinds of plasticizers were detected in the soft PVC toys. Diisononyl phthalate, di(2-ethylhexyl) phthalate, diisononyl adipate, and O-acetyl tributyl citrate were detected at high frequency, and in large amounts. The average total content of all plasticizers was 280 mg/g for the products purchased in fiscal 2000 and 227 mg/g for those in fiscal 2001. In fiscal 2001, antioxidants, 4-nonylphenol, and bisphenol A were investigated in addition to plasticizers.

Levels of phthalates and adipates in processed foods and migration of di-isononyl adipate from polyvinyl chloride film into foods

The levels of dibutyl phthalate (DBP), butylbenzyl phthalate (BBP), di-(2-ethylhexyl) phthalate (DEPHP), di-isononyl phthalate (DINP), di-(2-ethylhexyl) adipate (DEHA) and di-isononyl adipate (DINA) were determined in 50 processed foods (ham and sausage, fried dumpling and shao-mai, fish paste products, croquette and fried fish, bread, noodle, pickles, etc.). DBP, BBP, DEHP, DINP, DEHA, and DINA were contained at nd approximately 47.7, nd approximately 16.6, nd approximately 749, nd approximately 358, nd approximately 57.2 and nd approximately 20,200 ppb, respectively. High-level contamination of DINA was found in fish paste products, croquette and shao-mai, presumably because of migration from plasticized wrapping film using for food packaging. We studied the relationship between DINA migration from wrapped PVC film into fried croquette and its standing time after frying. When the croquette was wrapped immediately after frying, the migration from wrapping film into the croquette was highest (36,400 ng/g). On wrapping after standing for 5 min and 30 min, the migration level was reduced to 1/3.5 and 1/14 of the highest level, respectively.

Phthalates, Adipates, Citrate and Some of the Other Plasticizers Detected in Japanese Retail Foods: A survey.

Plasticizers in Japanese retail foods were determined by gas chromatography/mass spectrometry (GC/MS) (SIM). The plasticizers tested were as follows: dibutyl phthalate, butylbenzyl phthalate, di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate, di(2-ethylhexyl) adipate, diisononyl adipate (DINA), dialkyl adipate, dibutyl sebacate, Oacetyl tributyl citrate (ATBC) and diacetyllauroyl glycerol (DALG). A total of 93 samples were analyzed. For the analysis, each sample was extracted by a method suitable to its nature and cleaned using Florisil ® and Bondesil PSA ® dual layer columns. The recovery of plasticizers from fortified food samples was 62.0‐131.0%, except in the case of DINA. The limit of detection (LOD) was different for each sample species and plasticizers. For example, the LOD for plasticizers in retort-pouched baby food was 0.0004‐0.037 µg/g. A retort-pouched baby food sample was found to be contaminated by DEHP at the Japanese tolerable daily intake (TDI) level, 40 µg/kg/day. The source of contamination was presumed to be disposable gloves because the baby food was produced before the prohibition of DEHPcontaining poly vinyl chloride (PVC) gloves by the Japanese government. After that prohibition, products generally contained much lower levels of DEHP. A higher level of DALG was detected in the other baby food samples, although it became clear that DALG did not originate as contamination from plastics but was added as a food additive. ATBC was detected in bottled sake samples at levels of around 3‐7 µg/g, having migrated from the gasket of the bottle cap. ATBC and DALG levels in the above foods were quite low compared with their no observed adverse effect level (NOAEL) or guideline levels as food additives.

Identification of unknown substances in polyvinyl chloride gloves containing non-phthalate plasticizers

The use of polyvinyl chloride gloves containing di(2-ethylhexyl) phthalate for food contact applications is restricted. In their place, polyvinyl chloride gloves containing non-phthalate plasticizers (PVC-NP) have been introduced. They contained unknown substances, so they were studied by GC/MS, HR-MS and NMR. The chemical structures of the unknown substances were confirmed to be diethylene glycol dibenzoate, triethylene glycol dibenzoate, dipropylene glycol dibenzoate, and alkylsulfonic acid phenyl ester, which are plasticizers. Including di-isononyl adipate, the contents of the plasticizers were 37.5-48.9% in the PVC-NP gloves, and their migration levels were 1,010-1,390 ppm into n-heptane. These are very high levels. These plasticizers are not widely used for food contact polyvinyl chloride throughout the world, and they have also not been registered as self-standards by Japanese manufacturers. Careful consideration will be necessary for the selection of a suitable plasticizer substitute.

Additives in Polyvinyl Chloride and Polyvinylidene Chloride Products

The residue of 89 kinds of additives including plasticizers in polyvinyl chloride (PVC) and polyvinylidene chloride (PVDC) products were investigated. PVC wrapping films contained 14-38% of plasticizers, most of which were adipates, especially diisononyl adipate. However, few additives were observed in PVC containers. PVC gloves contained 34-55% of plasticizers, mostly di-2-ethylhexyl phthalate and di-2-ethylhexyl adipate, in all samples. The levels of plasticizers in toys were 8.7-45%, consisting mainly of diisononyl phthalate and di-2-ethylhexyl phthalate. On the other hand, the levels of plasticizers in PVDC wrapping films were only 2.7-7.8% (O-acetyl tributyl citrate and dibutyl sebacate). Nonylphenol was found in some PVC wrapping films, gloves and toys at concentrations of about 530-5, 500μg/g sample.

Decomposition of Adipate Plasticizers by Fresh Vegetables.

In our previous paper, we reported a phenomenon that adipate (AAE) utilized as the plasticizer for polyvinyl chloride cling films was hydrolyzed to alcohols and adipic acid when they were kept in contact with non-cooked foods. In this paper, the decomposition of adipates by fresh vegetables was investigated using di-2-ethylhexyl adipate (DEHA) and diisononyl adipate. AAE added to various fresh vegetables was decomposed after incubating at 35°C for 1 h to yield alcohols, which were undetected in the original vegetables. In the cases of fruit, cucumbers, tomatos and red peppers, it was found that the rate of the decomposion of AAE decreased as they were ripening. The AAE hydrolyzing component in cucumbers was extracted with 50 mM Tris-HCl buffer (pH 7.5) and only when 1% triton X-100 was added to the buffer the extraction was most efficient. The AAE decomposing activities of the extract showed the best result under the conditions of pH 7-7.5 and 35°C and were lost in the case of heating at 100°C for 5 min. This suggests that the decomposition of AAE is an enzymatic hydrolysis reaction. Other aliphatic dicarboxylic acid esters such as DEHA, di-2-ethylhexyl azelate, di-2-ethylhexyl sebacate and di-2-ethylhexyl dodecanediocate were also hydrolyzed by the cucumber extract, but as the carbon number of these acids increases, the rate of hydrolysis diminished. The molecular weight of the putative enzyme in the cucumber extract catalyzing the hydrolysis of AAE was estimated to be 25000-45000 by gel filtration chromatography on Sephadex G-100.

Migration of Adipate Plasticizers from Polyvinyl Chloride Films into Foods and Their Decomposition.

The migration of adipate plasticizers from polyvinyl chloride (PVC) films into foods, their decomposition and acute toxicity were investigated. Adipates were detected in many kinds of foods wrapped by using PVC films. They tended to migrate from the PVC films much more into foods cooked with oil, like croquettes, than into raw fish, meat and fresh vegetables. Adipates contained in PVC films were hydrolyzed to adipic acid and alcohol when allowed to keep in contact with non-cooked foods, especially swordfish and lotus roots for several days. And diisononyl adipate added to various foods was also cleaved into isononyl alcohol and adipic acid on standing at 30°C. A few kinds of bacteria which can hydrolyze adipates were isolated from the PVC films used to wrap various foods. It was suggested that the decomposition was mainly caused by bacteria. LD50 of diisononyl adipate and plasticizers (di-n-alkyl adipate 89%, acetyltributyl citrate 11%) which was extracted from PVC films were 36.3 g/kg and >48.0 g/kg, respectively.

An evaluation of the genotoxic potential of di-isononyl adipate.

Di-isononyl adipate (DINA) is one of a group of adipates used primarily as plasticizers. Concern over the mutagenic and carcinogenic potential of these materials was stimulated by the finding that one member of this class, di-(2-ethylhexyl) adipate (DEHA), induced liver tumors in female mice in a chronic feeding study. Accordingly, the genotoxic potential of DINA was evaluated in a battery of in vitro tests including the Salmonella/mammalian microsome mutagenicity assay, the mouse lymphoma TK +/-assay, and two tests of morphologic transforming ability, the BALB 3T3 and the Syrian hamster embryo in vitro transformation assays. DINA did not exhibit any evidence of mutagenic or transforming potential in any of the assays utilized.

Identification and Determination of Adipic Acid Esters in Polyvinyl Chloride Films

Two kinds of plasticizers were identified in polyvinyl chloride (PVC) films used for food packaging. One of them was diisononyl adipate, and the other was a mixture of di-n-hexyl adipate, n-hexyl-n-octyl adipate, n-hexyl-n-decyl adipate, di-n-octyl adipate, n-octyl-n-decyl adipate, di-n-decyl adipate and acetyl tributyl citrate.A method for determination of these adipates was developed as follows: adipates extracted from PVC with n-hexane were converted to dimethyl adipate (DMA) by treatment with boron trifluoride methanol complex. After methyl esterification, 10% sodium sulfate solution was added to the reacted solution and the DMA and constituent alcohols formed were extracted with n-hexane and determined by gas chromatography. DMA and constituent alcohols could be analyzed simultaneously on a single column of 15% PEG-1000.The value of adipates was calculated from that of DMA and alcohols.The yields of DMA from various adipates were above 90%. The amounts of adipates in PVC films were 12.0-22.0%.