Main applications of dioctyl phthalate_Kain Industrial Additives

Background and overview^[1]

Dioctyl phthalate is a colorless or light yellow transparent liquid with a special odor. Its boiling point is 386°C and its relative density is 0.980~0.983 (20/4°C). Insoluble in water, soluble in organic solvents such as ethanol and ether. It is prepared by the esterification reaction of phthalic anhydride and 2-ethylhexanol. It is one of the most widely used plasticizers in plastic processing. It has good comprehensive properties, high growth efficiency, low volatility, UV resistance, and cold resistance, which improves the softness and electrical properties of the product. It is an ideal main plasticizer. It has low toxicity, with a half-lethal dose greater than 30 g/kg body weight. The French Institute of Cancer Research fed four generations of rats with feed containing 0.05% of it, proving that it is non-toxic and non-carcinogenic. However, whether large doses have carcinogenic effects remains to be further studied. Britain, France, Japan, the Netherlands, Germany and other countries allow it to be used in plastic products that come into contact with food (except fatty foods), and the U.S. Food and Drug Administration allows it to be used in cellophane, coatings, adhesives and rubber products for food packaging. . It can also be used as a standard sample in chromatographic quantitative analysis. .

Apply^[2-5]

Dioctyl phthalate is widely used as a plasticizer for polyvinyl chloride, vinyl chloride copolymer, fiber resin acrylic resin and synthetic rubber. Using it in nitrocellulose paint can enhance the elasticity and tensile strength of the paint film. It can also be used as a softener for synthetic rubber (such as nitrile rubber) to improve the resilience of the product.

1) Prepare a solar cell conductive mixed slurry containing dioctyl phthalate, which is prepared from the following raw materials by weight: A material 52-56, B material 18-20, C material 22 -25, silane coupling agent KH602-2-3, silicone oil 1-2, polyamide wax 1-2, dioctyl phthalate 1-2. The conductive slurry obtained by the present invention does not contain lead, fully meets environmental protection requirements, and can be used in the production of solar cells. It can form strong adhesion on the surface of solar cells and have high photoelectric conversion efficiency. At the same time, silver powder and gold powder of different particle sizes are selected. Aluminum powder increases the contact area between particles, thereby improving the conductivity of the silver paste.

2) Prepare a protective coating against metal corrosion, which is prepared from the following raw materials by weight: sodium hexametaphosphate, 20 to 30 parts; sodium silicate, 5 to 15 parts; Shuangfei powder, 10 to 20 parts parts; chlorinated paraffin, 6 to 8 parts; water-based styrene acrylic resin, 15 to 25 parts; water-based polyurethane resin, 5 to 15 parts; silane coupling agent methyl tributyl ketone oxime silane, 15 to 25 parts; triphosphate Butyl ester, 8 to 12 parts; isobutyl acrylate, 4 to 6 parts; succinic acid, 1 to 3 parts; water, 60 to 70 parts; dioctyl phthalate and isothiazolinone, a total of 7 to 9 parts , the weight ratio of dioctyl phthalate and isothiazolinone is 6~8:1. The protective coating against metal rust provided by the present invention can significantly improve the corrosion resistance, water resistance, heat resistance and fingerprint resistance of the metal surface, which may be related to the weight of dioctyl phthalate and isothiazolinone in the raw materials. It is related to the ratio of parts by weight. When the ratio by weight of dioctyl phthalate and isothiazolinone is 6 to 8:1, the protective effect on the metal surface is the best.

3) Prepare an artificial leather without base fabric, which includes a surface layer, a foam layer and a back layer from top to bottom. The surface layer is prepared by including the following parts by weight of raw materials: 100 parts of polyvinyl chloride resin, 50-60 parts of dioctyl phthalate and 1-2 parts of heat stabilizer. The foaming layer is prepared by including the following weight parts of raw materials: 100 parts of polyvinyl chloride resin, 70-70 parts of dioctyl phthalate. 90 parts, 50-70 parts of filler, 2-3 parts of stabilizer and 3-4 parts of foaming agent. The back layer is prepared by including the following parts by weight of raw materials: 100 parts of polyvinyl chloride resin, 100 parts of diphthalate 50-60 parts of octyl ester and 1-2 parts of stabilizer. The invention also relates to a method for preparing artificial leather without base cloth. The base cloth-free artificial leather and its preparation method of the present invention can effectively enhance the tear strength of the leather; the tear strength is tested using a tensile machine, and the tear strength reaches 2.0Kg.

4) Prepare a polyvinyl chloride plastic and electric vehicle charging pile connection cable sheath material. PVC plastics include PVC resin, dioctyl phthalate, dioctyl sebacate, calcium zinc composite stabilizer, nitrile rubber, and SEBS rubber. SEBS rubber is a linear or star-shaped triembedded copolymer with styrene as the terminal segment and an ethylene-butene copolymer obtained by hydrogenating butadiene as the middle elastic block. PVC plastic uses SEBS rubber and nitrile rubber as auxiliary plasticizers, 100 parts of PVC resin, 10-30 parts of dioctyl phthalate, 1-20 parts of dioctyl sebacate, calcium and zinc composite Stabilizer 2-10 parts, nitrile rubber 0-25 parts, SEBS rubber 5-25 parts, calcium carbonate 0-50 parts. The invention also discloses an electric vehicle charging pile connecting cable sheath material made of the polyvinyl chloride plastic.

Preparation^[6]

A preparation method of dioctyl phthalate, comprising the following steps:

(1), esterification process

Put the prepared isooctyl alcohol into the reaction kettle first, then turn on the fan and add phthalic anhydride while stirring. In terms of mole fraction, isooctyl alcohol: phthalic anhydride = 2.5:1; add concentrated sulfuric acid, the dosage is by weight. In percentage terms, it is 0.2% to 1% of the amount of raw material isooctyl alcohol. In order to gradually proceed the esterification reaction to the end, the present invention uses excess alcohol as the water-carrying agent; then stirs and controls the temperature in the reaction kettle at 100 to 250°C. , reaction takes about 16-20 hours;

(2) Neutralization process

Add alkali solution into the reaction kettle, its concentration is 4% to 6% in terms of mass fraction, and its dosage is 2% to 4% of the amount of raw material benzene in terms of weight percentage.%; At this time, the temperature is controlled at 60-90°C, the stirring speed is controlled at 50-70 revolutions per minute, and the acid value is controlled at 0.05 mgKOH/g at the end of neutralization. After neutralization and washing, distillation under reduced pressure gives o-benzene. Crude dioctyl dicarboxylate;

(3), dealcoholization process

Dealcoholization under vacuum requires the system vacuum to be greater than 620mmHg column, the temperature is controlled at 80~140℃, dealcoholization under reduced pressure until there is no split; add adsorbent and filter aid, the adsorbent components are SiO2, AL2O3, Fe2O3 , MgO, etc., the composition of the filter aid (diatomite) is SiO2, AL2O3, Fe2O3, CaO, MgO; press filtration to obtain the qualified finished product of dioctyl phthalate; the main purpose of this process is to pass the adsorbent and aid The adsorption and decolorization effect of the filter agent ensures the color and volume resistivity of the product DOP, and at the same time removes trace amounts of catalyst and other mechanical impurities remaining in the DOP. Finally, high-quality DOP is obtained.

(4), isooctyl alcohol recovery process

Heat the wastewater to continuously maintain the azeotropic state, so that the isooctyl alcohol vapor is condensed and stratified. The upper layer of isooctyl alcohol is continuously separated from the system, while the lower layer of water is continuously refluxed into the tower to continue distillation until no isooctyl alcohol is distilled out. So far, the recovery has used hypergravity bed recovery.